summaryrefslogtreecommitdiff
path: root/tools/resolver-visualize/Main.hs
blob: 61ceab3295316d9b15c7ffbca54f112f8521a845 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
#!/usr/bin/env runhaskell

module Main where

import Control.Monad.Reader
import qualified Control.Monad.State as State
import Control.Monad.Trans(liftIO)
import Data.ByteString.Char8 as ByteString(ByteString, empty, hGet, pack, unpack)
import Data.List(intersperse)
import Dot
import Graphics.UI.Gtk
import Graphics.UI.Gtk.Glade
import Graphics.UI.Gtk.SourceView
import Numeric
import System.Environment(getArgs)
import System.Glib.MainLoop
import System.Glib.Types
import Data.IORef
import Data.List
import Data.Maybe
import qualified Data.Map as Map
import qualified Data.Set as Set
import Data.Tree
import Resolver.Log
import Resolver.Types
import Resolver.Util
import System.IO
import System.Time
import Text.Printf

xmlFilename = "resolver-visualize.glade"

data MainLoopContext = MainLoopContext { mainLoop :: MainLoop,
                                         numMainWindows :: IORef Integer }

type MainM = ReaderT MainLoopContext IO

runMain :: (MainM a) -> MainLoopContext -> IO a
runMain = runReaderT

mainWindowClosed :: MainM ()
mainWindowClosed = do ctx <- ask
                      liftIO $ do modifyIORef (numMainWindows ctx) (+(-1))
                                  num <- readIORef (numMainWindows ctx)
                                  when (num == 0) (mainLoopQuit (mainLoop ctx))

mainWindowOpened :: MainM ()
mainWindowOpened = do ctx <- ask
                      liftIO $ modifyIORef (numMainWindows ctx) (+1)

-- | Information about a loaded log file.
data LoadedLogFile =
    LoadedLogFile { logFile :: LogFile }

data TextColumnInfo = TextColumnInfo { textColumn   :: TreeViewColumn,
                                       textRenderer :: CellRendererText }

textColumnNew :: String -> IO TextColumnInfo
textColumnNew name = do col      <- treeViewColumnNew
                        treeViewColumnSetTitle col name
                        renderer <- cellRendererTextNew
                        cellLayoutPackEnd col renderer True
                        return TextColumnInfo { textColumn   = col,
                                                textRenderer = renderer }

-- | Information about the columns and renderers of the tree display.
data TreeViewColumnInfo =
    TreeViewColumnInfo { treeViewText        :: TextColumnInfo,
                         treeViewNumChoices  :: TextColumnInfo,
                         treeViewBrokenDeps  :: TextColumnInfo,
                         treeViewStepNum     :: TextColumnInfo,
                         treeViewChildren    :: TextColumnInfo,
                         treeViewHeight      :: TextColumnInfo,
                         treeViewSubtreeSize :: TextColumnInfo,
                         treeViewTier        :: TextColumnInfo,
                         treeViewScore       :: TextColumnInfo }

treeViewColumnInfoRenderers :: TreeViewColumnInfo -> [CellRenderer]
treeViewColumnInfoRenderers inf =
    [ toCellRenderer $ textRenderer $ treeViewText inf,
      toCellRenderer $ textRenderer $ treeViewNumChoices inf,
      toCellRenderer $ textRenderer $ treeViewBrokenDeps inf,
      toCellRenderer $ textRenderer $ treeViewStepNum inf,
      toCellRenderer $ textRenderer $ treeViewChildren inf,
      toCellRenderer $ textRenderer $ treeViewHeight inf,
      toCellRenderer $ textRenderer $ treeViewSubtreeSize inf,
      toCellRenderer $ textRenderer $ treeViewTier inf,
      toCellRenderer $ textRenderer $ treeViewScore inf ]

treeViewColumnInfoColumns :: TreeViewColumnInfo -> [TreeViewColumn]
treeViewColumnInfoColumns inf =
    [ textColumn $ treeViewText inf,
      textColumn $ treeViewNumChoices inf,
      textColumn $ treeViewBrokenDeps inf,
      textColumn $ treeViewStepNum inf,
      textColumn $ treeViewChildren inf,
      textColumn $ treeViewHeight inf,
      textColumn $ treeViewSubtreeSize inf,
      textColumn $ treeViewTier inf,
      textColumn $ treeViewScore inf ]

-- | Discard attribute bindings for the tree view.
treeViewColumnInfoClear :: TreeViewColumnInfo -> IO ()
treeViewColumnInfoClear inf = let cols = treeViewColumnInfoColumns inf in
                              mapM_ cellLayoutClear cols

newTreeViewColumns :: IO TreeViewColumnInfo
newTreeViewColumns =
    do text              <- textColumnNew "Description"
       numChoices        <- textColumnNew "Choices"
       brokenDeps        <- textColumnNew "Broken Deps"
       stepNum           <- textColumnNew "Order"
       children          <- textColumnNew "Children"
       height            <- textColumnNew "Height"
       subtreeSize       <- textColumnNew "Size"
       tier              <- textColumnNew "Tier"
       score             <- textColumnNew "Score"
       return TreeViewColumnInfo { treeViewText          = text,
                                   treeViewNumChoices    = numChoices,
                                   treeViewBrokenDeps    = brokenDeps,
                                   treeViewStepNum       = stepNum,
                                   treeViewChildren      = children,
                                   treeViewHeight        = height,
                                   treeViewSubtreeSize   = subtreeSize,
                                   treeViewTier          = tier,
                                   treeViewScore         = score }

-- | Information about the columns and renderers of the chronological
-- display.
data ChronologicalViewColumnInfo =
    ChronologicalViewColumnInfo { chronViewNumChoices  :: TextColumnInfo,
                                  chronViewBrokenDeps  :: TextColumnInfo,
                                  chronViewStepNum     :: TextColumnInfo,
                                  chronViewChildren    :: TextColumnInfo,
                                  chronViewHeight      :: TextColumnInfo,
                                  chronViewSubtreeSize :: TextColumnInfo,
                                  chronViewTier        :: TextColumnInfo,
                                  chronViewScore       :: TextColumnInfo }

chronViewColumnInfoRenderers :: ChronologicalViewColumnInfo -> [CellRenderer]
chronViewColumnInfoRenderers inf =
    [ toCellRenderer $ textRenderer $ chronViewNumChoices inf,
      toCellRenderer $ textRenderer $ chronViewBrokenDeps inf,
      toCellRenderer $ textRenderer $ chronViewStepNum inf,
      toCellRenderer $ textRenderer $ chronViewChildren inf,
      toCellRenderer $ textRenderer $ chronViewHeight inf,
      toCellRenderer $ textRenderer $ chronViewSubtreeSize inf,
      toCellRenderer $ textRenderer $ chronViewTier inf,
      toCellRenderer $ textRenderer $ chronViewScore inf ]

chronViewColumnInfoColumns :: ChronologicalViewColumnInfo -> [TreeViewColumn]
chronViewColumnInfoColumns inf =
    [ textColumn $ chronViewNumChoices inf,
      textColumn $ chronViewBrokenDeps inf,
      textColumn $ chronViewStepNum inf,
      textColumn $ chronViewChildren inf,
      textColumn $ chronViewHeight inf,
      textColumn $ chronViewSubtreeSize inf,
      textColumn $ chronViewTier inf,
      textColumn $ chronViewScore inf ]

-- | Discard attribute bindings for the chronological view.
chronViewColumnInfoClear :: ChronologicalViewColumnInfo -> IO ()
chronViewColumnInfoClear inf = let cols = chronViewColumnInfoColumns inf in
                               mapM_ cellLayoutClear cols

newChronViewColumns :: IO ChronologicalViewColumnInfo
newChronViewColumns =
    do numChoices        <- textColumnNew "Choices"
       brokenDeps        <- textColumnNew "Broken Deps"
       stepNum           <- textColumnNew "Order"
       children          <- textColumnNew "Children"
       height            <- textColumnNew "Height"
       subtreeSize       <- textColumnNew "Size"
       tier              <- textColumnNew "Tier"
       score             <- textColumnNew "Score"
       return ChronologicalViewColumnInfo {
                    chronViewNumChoices   = numChoices,
                    chronViewBrokenDeps   = brokenDeps,
                    chronViewStepNum      = stepNum,
                    chronViewChildren     = children,
                    chronViewHeight       = height,
                    chronViewSubtreeSize  = subtreeSize,
                    chronViewTier         = tier,
                    chronViewScore        = score
                  }

-- | Information about the columns and renderers of the run list.
data RunListColumnInfo =
    RunListColumnInfo { runListNumber :: TextColumnInfo,
                        runListLength :: TextColumnInfo }

runListInfoRenderers :: RunListColumnInfo -> [CellRenderer]
runListInfoRenderers inf =
    [ toCellRenderer $ textRenderer $ runListNumber inf,
      toCellRenderer $ textRenderer $ runListLength inf ]

runListInfoColumns :: RunListColumnInfo -> [TreeViewColumn]
runListInfoColumns inf =
    [ textColumn $ runListNumber inf,
      textColumn $ runListLength inf ]

-- | Discard attribute bindings for the run list.
runListColumnInfoClear :: RunListColumnInfo -> IO ()
runListColumnInfoClear inf = let cols = runListInfoColumns inf in
                             mapM_ cellLayoutClear cols

newRunListColumns :: IO RunListColumnInfo
newRunListColumns =
    do number     <- textColumnNew "Run Number"
       len        <- textColumnNew "Run Length"
       return RunListColumnInfo {
                    runListNumber = number,
                    runListLength = len
                  }

type TreeViewStore  = TreeStore TreeViewEntry
type ChronViewStore = ListStore ChronViewEntry
type RunListStore   = ListStore (Integer, [ProcessingStep])

-- | Parameters the user can set at the command-line.
data Params =
    Params {
      -- | The maximum number of steps to visualize (the whole file is
      -- always loaded, but only this many are rendered).
      maxSteps :: Maybe Integer,
      -- | The first step to start rendering.
      firstStep :: Maybe Integer,
      -- | Where and whether to send dot output.
      dotOutput :: Maybe String
    } deriving(Eq, Ord, Show)
defaultParams = Params { maxSteps  = Nothing,
                         firstStep = Nothing,
                         dotOutput = Nothing }

-- | Shared context for the visualizer.
data VisualizeContext =
    VisualizeContext { treeView :: TreeView,
                       treeViewColumnInfo :: TreeViewColumnInfo,
                       treeViewStore :: TreeViewStore,
                       chronologicalView :: TreeView,
                       chronologicalViewColumnInfo :: ChronologicalViewColumnInfo,
                       chronologicalViewStore :: ChronViewStore,
                       runList :: TreeView,
                       runListColumnInfo :: RunListColumnInfo,
                       runListStore :: RunListStore,
                       logView :: SourceView,
                       mainContext :: MainLoopContext,
                       params :: Params,
                       loadedFile :: IORef (Maybe LoadedLogFile),
                       activeRun  :: IORef (Maybe (Integer, [ProcessingStep])) }

-- | State monad for the visualizer.
type VisM = ReaderT VisualizeContext IO

-- Accessors for state.
runVis :: (VisM a) -> VisualizeContext -> IO a
runVis = runReaderT

getTreeView :: VisM TreeView
getTreeView = do ctx <- ask; return $ treeView ctx

getTreeViewStore :: VisM TreeViewStore
getTreeViewStore = do ctx <- ask; return $ treeViewStore ctx

getTreeViewColumnInfo :: VisM TreeViewColumnInfo
getTreeViewColumnInfo = do ctx <- ask; return $ treeViewColumnInfo ctx

getChronologicalView :: VisM TreeView
getChronologicalView = do ctx <- ask; return $ chronologicalView ctx

getChronologicalViewColumnInfo :: VisM ChronologicalViewColumnInfo
getChronologicalViewColumnInfo = do ctx <- ask; return $ chronologicalViewColumnInfo ctx

getChronologicalViewStore :: VisM ChronViewStore
getChronologicalViewStore = do ctx <- ask; return $ chronologicalViewStore ctx

getRunList :: VisM TreeView
getRunList = do ctx <- ask; return $ runList ctx

getRunListColumnInfo :: VisM RunListColumnInfo
getRunListColumnInfo = do ctx <- ask; return $ runListColumnInfo ctx

getRunListStore :: VisM RunListStore
getRunListStore = do ctx <- ask; return $ runListStore ctx

getLogView :: VisM SourceView
getLogView = do ctx <- ask; return $ logView ctx

getMainCtx :: VisM MainLoopContext
getMainCtx = do ctx <- ask; return $ mainContext ctx

getParams :: VisM Params
getParams = do ctx <- ask; return $ params ctx


getLog :: VisM (Maybe LogFile)
getLog = do ctx <- ask
            maybeInf <- liftIO $ readIORef $ loadedFile ctx
            return $ fmap logFile maybeInf

getRunNumber :: VisM (Maybe Integer)
getRunNumber = do ctx <- ask
                  runInf <- liftIO $ readIORef $ activeRun ctx
                  return $ fmap fst runInf

isActiveRun :: Integer -> VisM Bool
isActiveRun n = do current <- getRunNumber
                   case current of
                     Nothing   -> return False
                     (Just n') -> return (n == n')

--getTreeViewStore :: VisM (Maybe (TreeStore TreeViewEntry))
--getTreeViewStore = do ctx <- ask
--                      maybeInf <- liftIO $ readIORef $ loadedFile ctx
--                      return $ fmap treeViewStore maybeInf

-- | Stores tree-structure information about an entry.
data EntryTreeInfo = EntryTreeInfo {
      treeInfoChildren    :: Integer,
      treeInfoHeight      :: Integer,
      treeInfoSubtreeSize :: Integer
    } deriving(Ord, Eq, Show)

getTreeInfo :: ProcessingStep -> EntryTreeInfo
getTreeInfo (ProcessingStep { stepSuccessors = steps,
                              stepDepth      = height,
                              stepBranchSize = branchSize }) = EntryTreeInfo { treeInfoChildren    = toInteger $ length steps,
                                                                               treeInfoHeight      = height,
                                                                               treeInfoSubtreeSize = branchSize }

-- Each row in the tree display is either the root of the search, a
-- processing step (possibly with no parent!), a solution that was
-- enqueued but never visited, or a note about a problem rendering the
-- tree.
data TreeViewEntry =
    Root {
      entryStep         :: ProcessingStep,
      entryNumChoices   :: Integer,
      entryBrokenDeps   :: Integer,
      entryStepNum      :: Integer,
      entryTreeInfo     :: EntryTreeInfo
    }
  | Step {
      entryStep         :: ProcessingStep,
      entryChoice       :: LinkChoice,
      entryNumChoices   :: Integer,
      entryBrokenDeps   :: Integer,
      entryStepNum      :: Integer,
      entryTreeInfo     :: EntryTreeInfo
    }
  -- | The maximum number of search nodes was rendered.
  | Horizon {
      entryChoice       :: LinkChoice,
      entryStepNum      :: Integer,
      entryTreeInfo     :: EntryTreeInfo
    }
  -- | A Step node would have been produced, but the
  -- same solution was already generated as a Step
  -- node.  The attached Solution node could be used
  -- to, e.g., look up the tree node associated with
  -- the link.
  | AlreadyGeneratedStep {
      entrySol          :: Solution,
      entryChoice       :: LinkChoice,
      entryNumChoices   :: Integer,
      entryStepNum      :: Integer,
      entryBrokenDeps   :: Integer,
      entryTextStart    :: Integer,
      entryTextLength   :: Integer
    }
  | NoStep {
      entrySol          :: Solution,
      entryChoice       :: LinkChoice,
      entryBrokenDeps   :: Integer,
      entryNumChoices   :: Integer
    }
  | Error {
      entryErrorText    :: String,
      entryStepNum      :: Integer
    }

forceList :: [a] -> [a]
forceList = foldr (\a b -> a `seq` (a:b)) []

-- Each node in the tree refers either to a node's successor or to a
-- number of nodes below that node (precomputed).
data SuccessorOrHorizon = NodeSuccessor Successor
                        | NodeHorizon TreeViewEntry

-- | The tree-view building monad contains local state remembering
-- which nodes have already been incorporated into the tree, so we
-- don't display them more than once.
type BuildTreeView = State.State (Set.Set Solution)
unfoldSuccessor :: Params -> SuccessorOrHorizon -> BuildTreeView (TreeViewEntry, [SuccessorOrHorizon])
unfoldSuccessor params (NodeHorizon entry) =
    return (entry, [])
unfoldSuccessor params (NodeSuccessor (Successor step choice forced)) =
    do seen <- State.get
       let sol        = stepSol step
           stepNum    = stepOrder step
       case undefined of
         _ | maybe False (stepNum>=) (maxSteps params) ->
               let numChoices     = toInteger $ Map.size $ solChoices $ stepSol step
                   brokenDeps     = toInteger $ Set.size $ solBrokenDeps $ stepSol step
                   treeInfo       = getTreeInfo step
                   horizon        = Horizon { entryChoice     = choice,
                                              entryStepNum    = stepNum,
                                              entryTreeInfo   = treeInfo } in
               step `seq` choice `seq` stepNum `seq` treeInfo `seq`
               do return (Step { entryStep       = step,
                                 entryChoice     = choice,
                                 entryStepNum    = stepNum,
                                 entryNumChoices = numChoices,
                                 entryBrokenDeps = brokenDeps,
                                 entryTreeInfo   = treeInfo },
                          [NodeHorizon horizon])
           | sol `Set.member` seen ->
               let numChoices = toInteger $ Map.size $ solChoices sol
                   brokenDeps = toInteger $ Set.size $ solBrokenDeps sol
                   textStart  = stepTextStart step
                   textLength = stepTextLength step in
               return $ sol `seq` choice `seq` stepNum `seq` textStart `seq`
               textLength `seq` numChoices `seq` brokenDeps `seq`
               (AlreadyGeneratedStep { entrySol        = sol,
                                       entryChoice     = choice,
                                       entryStepNum    = stepNum,
                                       entryNumChoices = numChoices,
                                       entryBrokenDeps = brokenDeps,
                                       entryTextStart  = textStart,
                                       entryTextLength = textLength },
                [])
           | otherwise ->
               let newState       = Set.insert sol seen
                   numChoices     = toInteger $ Map.size $ solChoices $ stepSol step
                   brokenDeps     = toInteger $ Set.size $ solBrokenDeps $ stepSol step
                   treeInfo       = getTreeInfo step in
               step `seq` choice `seq` stepNum `seq` newState `seq`
               numChoices `seq` brokenDeps `seq` treeInfo `seq`
               do State.put newState
                  return (Step { entryStep       = step,
                                 entryChoice     = choice,
                                 entryStepNum    = stepNum,
                                 entryNumChoices = numChoices,
                                 entryBrokenDeps = brokenDeps,
                                 entryTreeInfo   = treeInfo },
                          forceList $ map NodeSuccessor $ stepSuccessors step)
unfoldSuccessor _ (NodeSuccessor (Unprocessed sol choice forced)) =
    let brokenDeps = toInteger $ Set.size $ solBrokenDeps sol
        numChoices = toInteger $ Map.size $ solChoices sol in
    sol `seq` choice `seq` brokenDeps `seq` numChoices `seq`
    return (NoStep { entrySol = sol,
                     entryChoice = choice,
                     entryBrokenDeps = brokenDeps,
                     entryNumChoices = numChoices },
            [])

runToForest :: Params -> [ProcessingStep] -> Forest TreeViewEntry
runToForest params steps =
    case steps of
      [] -> [Node (Error { entryErrorText = "No steps in this run.",
                           entryStepNum = 0 }) []]
      (first:rest) -> let hasRoot        = maybe False (==0) (firstStep params)
                          root           = if hasRoot then Just first else Nothing
                          droppedSteps   = maybe steps (\n -> genericDrop n steps) (firstStep params)
                          droppedRest    = if hasRoot then drop 1 droppedSteps else droppedSteps
                          truncatedRest  = maybe droppedRest (\n -> genericTake n droppedRest) (maxSteps params) in
                      State.evalState (makeWholeTree root truncatedRest) Set.empty
    where makeTree :: (ProcessingStep -> TreeViewEntry) -> ProcessingStep -> BuildTreeView (Maybe (Tree TreeViewEntry))
          makeTree f root =
              do seen <- State.get
                 let rootSol = stepSol root
                 (if rootSol `Set.member` seen
                  then return $ Nothing
                  else do State.put $ Set.insert rootSol seen
                          let rootSucc = stepSuccessors root
                          succ <- unfoldForestM (unfoldSuccessor params) (map NodeSuccessor rootSucc)
                          return $ f `seq` root `seq` forceList succ `seq` Just $ Node (f root) succ)
          makeWholeTree :: Maybe ProcessingStep -> [ProcessingStep] -> BuildTreeView (Forest TreeViewEntry)
          makeWholeTree root rest =
              do first <- maybe (return Nothing) (makeTree makeRootTree) root
                 rest' <- sequence $ map (makeTree makeOrphanedTree) rest
                 return $ catMaybes (first:rest')
          makeRootTree     root = let numChoices = toInteger $ Map.size $ solChoices $ stepSol root
                                      brokenDeps = toInteger $ Set.size $ solBrokenDeps $ stepSol root
                                      stepNum = stepOrder root
                                      treeInfo = getTreeInfo root in
                                  root `seq` numChoices `seq` brokenDeps `seq` stepNum `seq` treeInfo `seq`
                                  Root { entryStep       = root,
                                         entryNumChoices = numChoices,
                                         entryBrokenDeps = brokenDeps,
                                         entryStepNum    = stepOrder root,
                                         entryTreeInfo   = getTreeInfo root }
          makeOrphanedTree root = let numChoices = toInteger $ Map.size $ solChoices $ stepSol root
                                      brokenDeps = toInteger $ Set.size $ solBrokenDeps $ stepSol root
                                      stepNum = stepOrder root
                                      treeInfo = getTreeInfo root in
                                  root `seq` numChoices `seq` brokenDeps `seq` stepNum `seq` treeInfo `seq`
                                  Step { entryStep       = root,
                                         entryChoice     = Unknown,
                                         entryNumChoices = numChoices,
                                         entryBrokenDeps = brokenDeps,
                                         entryStepNum    = stepNum,
                                         entryTreeInfo   = treeInfo }

class PP a where
    ppS :: a -> ShowS

instance PP Version where
    ppS (Version pkg verName) = ppS pkg . (' ':) . (unpack verName++)

instance PP Package where
    ppS (Package pkgName) = (unpack pkgName++)

instance PP Dep where
    ppS (Dep src solvers isSoft) = let arrow = if isSoft
                                               then " -S> {"
                                               else " -> {" in
                                   ppS src . (arrow++) . (\x -> foldr (++) x $ intersperse ", " $ map pp solvers) . ('}':)

pp x = ppS x ""

choiceText :: LinkChoice -> String
choiceText (LinkChoice (InstallVersion ver _ _)) = "Install " ++ pp ver
choiceText (LinkChoice (BreakSoftDep d)) = "Break " ++ pp d
choiceText Unknown = "(...)"

-- Column definitions for tree view entries.
entryColumnText :: TreeViewEntry -> String
entryColumnText (Root {}) = "Root"
entryColumnText (Step { entryChoice = choice}) = choiceText choice
entryColumnText (Horizon { entryTreeInfo = inf }) = (show $ treeInfoChildren inf) ++ " search nodes..."
entryColumnText (AlreadyGeneratedStep { entryChoice = choice }) = "Already seen: " ++ choiceText choice
entryColumnText (NoStep { entryChoice = choice }) = "Never visited: " ++ choiceText choice
entryColumnText (Error { entryErrorText = err }) = err

entryColumnNumChoices :: TreeViewEntry -> String
entryColumnNumChoices (Root { entryNumChoices = n })                    = show n
entryColumnNumChoices (Step { entryNumChoices = n })                    = show n
entryColumnNumChoices (Horizon {})                                      = ""
entryColumnNumChoices (AlreadyGeneratedStep { entryNumChoices = n })    = show n
entryColumnNumChoices (NoStep { entryNumChoices = n })                  = show n
entryColumnNumChoices (Error {})                                        = ""

entryColumnBrokenDeps :: TreeViewEntry -> String
entryColumnBrokenDeps (Root { entryBrokenDeps = n })                    = show n
entryColumnBrokenDeps (Step { entryBrokenDeps = n })                    = show n
entryColumnBrokenDeps (Horizon {})                                      = ""
entryColumnBrokenDeps (AlreadyGeneratedStep { entryBrokenDeps = n })    = show n
entryColumnBrokenDeps (NoStep { entryBrokenDeps = n })                  = show n
entryColumnBrokenDeps (Error {})                                        = ""

entryColumnStepNum :: TreeViewEntry -> String
entryColumnStepNum (Root { entryStepNum = n })                          = show n
entryColumnStepNum (Step { entryStepNum = n })                          = show n
entryColumnStepNum (Horizon { entryStepNum = n })                       = show n
entryColumnStepNum (AlreadyGeneratedStep { entryStepNum = n })          = show n
entryColumnStepNum (NoStep {})                                          = ""
entryColumnStepNum (Error {})                                           = ""

entryColumnChildren :: TreeViewEntry -> String
entryColumnChildren (Root { entryTreeInfo = inf })                      = show $ treeInfoChildren inf
entryColumnChildren (Step { entryTreeInfo = inf })                      = show $ treeInfoChildren inf
entryColumnChildren (Horizon { entryTreeInfo = inf })                   = show $ treeInfoChildren inf
entryColumnChildren (AlreadyGeneratedStep {})                           = ""
entryColumnChildren (NoStep { })                                        = ""
entryColumnChildren (Error {})                                          = ""


entryColumnHeight :: TreeViewEntry -> String
entryColumnHeight (Root { entryTreeInfo = inf })                        = show $ treeInfoHeight inf
entryColumnHeight (Step { entryTreeInfo = inf })                        = show $ treeInfoHeight inf
entryColumnHeight (Horizon { entryTreeInfo = inf })                     = show $ treeInfoHeight inf
entryColumnHeight (AlreadyGeneratedStep { })                            = ""
entryColumnHeight (NoStep { })                                          = ""
entryColumnHeight (Error {})                                            = ""

entryColumnSubtreeSize :: TreeViewEntry -> String
entryColumnSubtreeSize (Root { entryTreeInfo = inf })                   = show $ treeInfoSubtreeSize inf
entryColumnSubtreeSize (Step { entryTreeInfo = inf })                   = show $ treeInfoSubtreeSize inf
entryColumnSubtreeSize (Horizon { entryTreeInfo = inf })                = show $ treeInfoSubtreeSize inf
entryColumnSubtreeSize (AlreadyGeneratedStep { })                       = ""
entryColumnSubtreeSize (NoStep { })                                     = ""
entryColumnSubtreeSize (Error {})                                       = ""

entryColumnTier :: TreeViewEntry -> String
entryColumnTier (Root { entryStep = step })                             = show $ solTier $ stepSol step
entryColumnTier (Step { entryStep = step })                             = show $ solTier $ stepSol step
entryColumnTier (Horizon {})                                            = ""
entryColumnTier (AlreadyGeneratedStep { entrySol = sol })               = show $ solTier sol
entryColumnTier (NoStep { entrySol = sol })                             = show $ solTier sol
entryColumnTier (Error {})                                              = ""

entryColumnScore :: TreeViewEntry -> String
entryColumnScore (Root { entryStep = step })                            = show $ solScore $ stepSol step
entryColumnScore (Step { entryStep = step })                            = show $ solScore $ stepSol step
entryColumnScore (Horizon {})                                           = ""
entryColumnScore (AlreadyGeneratedStep { entrySol = sol })              = show $ solScore sol
entryColumnScore (NoStep { entrySol = sol })                            = show $ solScore sol
entryColumnScore (Error {})                                             = ""

renderTreeView :: Params -> [ProcessingStep] -> TreeViewStore -> IO ()
renderTreeView params steps model =
    do let forest = runToForest params steps
           taggedForest = zip [0..] forest
       treeStoreClear model
       mapM_ (\(n, tree) -> treeStoreInsertTree model [] n tree)
             taggedForest

data ChronViewEntry =
    ChronStep { chronNumChoices   :: Integer,
                chronBrokenDeps   :: Integer,
                chronStepNum      :: Integer,
                chronChildren     :: Integer,
                chronHeight       :: Integer,
                chronSubtreeSize  :: Integer,
                chronTier         :: Tier,
                chronScore        :: Integer,
                chronStep         :: ProcessingStep }

makeChronStep :: ProcessingStep -> ChronViewEntry
makeChronStep step =
    let numChoices  = toInteger $ Map.size $ solChoices $ stepSol step
        brokenDeps  = toInteger $ Set.size $ solBrokenDeps $ stepSol step
        stepNum     = stepOrder step
        children    = toInteger $ length $ stepSuccessors step
        height      = stepDepth step
        subtreeSize = stepBranchSize step
        tier        = solTier $ stepSol step
        score       = solScore $ stepSol step in
    numChoices `seq` brokenDeps `seq` stepNum `seq` children `seq` height `seq` subtreeSize `seq` step `seq` tier `seq` score `seq`
    ChronStep { chronNumChoices  = numChoices,
                chronBrokenDeps  = brokenDeps,
                chronStepNum     = stepNum,
                chronChildren    = children,
                chronHeight      = height,
                chronSubtreeSize = subtreeSize,
                chronStep        = step,
                chronTier        = tier,
                chronScore       = score }

renderChronView :: Params -> [ProcessingStep] -> ChronViewStore -> IO ()
renderChronView params steps model =
    do let stepsAdvanced  = maybe steps (\n -> genericDrop n steps) (firstStep params)
           stepsTruncated = maybe stepsAdvanced (\n -> genericTake n stepsAdvanced) (maxSteps params)
           list           = [ makeChronStep step | step <- stepsTruncated ]
       listStoreClear model
       mapM_ (listStoreAppend model) list

showText :: Integer -> Integer -> VisM ()
showText start len =
    do log      <- getLog
       logView  <- getLogView
       liftIO $ do
         logBuffer <- textViewGetBuffer logView
         (case log of
            Nothing -> textBufferSetText logBuffer ""
            Just f  -> do let h = logFileH f
                          hSeek h AbsoluteSeek start
                          s <- ByteString.hGet h (fromInteger len)
                          textBufferSetText logBuffer $ unpack s)

stepSelected :: Maybe ProcessingStep -> VisM ()
stepSelected Nothing = return () -- Clear the log view?
stepSelected (Just step) = showText (stepTextStart step) (stepTextLength step)

setupTextColumn inf model ops =
    cellLayoutSetAttributes (textColumn inf) (textRenderer inf) model ops

setRun :: Maybe (Integer, [ProcessingStep]) -> VisM ()
setRun Nothing =
    do treeView         <- getTreeView
       chronView        <- getChronologicalView

       treeStore        <- getTreeViewStore
       chronStore       <- getChronologicalViewStore

       treeViewColInfo  <- getTreeViewColumnInfo
       chronViewColInfo <- getChronologicalViewColumnInfo

       liftIO $ do treeStoreClear treeStore
                   listStoreClear chronStore

setRun (Just (n, steps)) =
    do isActive <- isActiveRun n
       unless isActive $
            do ctx <- ask
               treeView         <- getTreeView
               chronView        <- getChronologicalView

               treeStore        <- getTreeViewStore
               chronStore       <- getChronologicalViewStore

               treeViewColInfo  <- getTreeViewColumnInfo
               chronViewColInfo <- getChronologicalViewColumnInfo

               params           <- getParams

               logView <- getLogView
               liftIO $ do -- Update the UI for the new log file.
                 rawLogViewBuffer <- textViewGetBuffer logView
                 textBufferSetText rawLogViewBuffer ""

                 renderTreeView  params steps treeStore
                 renderChronView params steps chronStore

setLog :: LogFile -> VisM ()
setLog lf =
    do runModel <- getRunListStore
       runView  <- getRunList
       ctx      <- ask
       liftIO $ do listStoreClear runModel
                   mapM_ (listStoreAppend runModel) $ (zip [1..] $ runs lf)
                   -- Make sure the first iterator is selected.
                   firstIter <- treeModelGetIterFirst runModel
                   selection <- treeViewGetSelection runView
                   (case firstIter of
                      Nothing -> return ()
                      Just i  -> treeSelectionSelectIter selection i)
                   writeIORef (loadedFile ctx) $ Just LoadedLogFile { logFile = lf }
       return ()

-- | Load a widget from the Glade file by name.
loadXmlWidget :: WidgetClass a => String -> (GObject -> a) -> IO (GladeXML, a)
loadXmlWidget widgetName cast =
    do x <- xmlNewWithRootAndDomain xmlFilename (Just widgetName) Nothing
       case x of
         Nothing -> error ("Can't load " ++ (show xmlFilename))
         Just xml -> do w <- xmlGetWidget xml cast widgetName
                        return (xml, w)

-- | Load the main window from the Glade file.
loadMainWindowXML :: IO (GladeXML, Window)
loadMainWindowXML = loadXmlWidget "main_window" castToWindow

-- | Load the About box from the Glade file.
loadAboutBoxXML :: IO (GladeXML, AboutDialog)
loadAboutBoxXML = loadXmlWidget "about_box" castToAboutDialog

-- | Load the loading progress window from the Glade file.
loadLoadingProgressXML :: IO (GladeXML, Window)
loadLoadingProgressXML = loadXmlWidget "window_load_progress" castToWindow

setupMainWindow :: GladeXML -> IO SourceView
setupMainWindow xml =
    do sourceViewHolder <- xmlGetWidget xml castToScrolledWindow "scrolledwindow_sourceview"
       sourceView <- sourceViewNew
       sourceViewSetShowLineNumbers sourceView True
       textViewSetEditable sourceView False
       containerAdd sourceViewHolder sourceView
       return sourceView

createMainWindowColumns :: GladeXML -> MainM (TreeViewColumnInfo, ChronologicalViewColumnInfo, RunListColumnInfo)
createMainWindowColumns xml =
    liftIO $ do treeViewCols  <- newTreeViewColumns
                chronViewCols <- newChronViewColumns
                runListCols   <- newRunListColumns
                return (treeViewCols, chronViewCols, runListCols)

createMainWindowStores :: TreeViewColumnInfo -> ChronologicalViewColumnInfo -> RunListColumnInfo -> IO (TreeViewStore, ChronViewStore, RunListStore)
createMainWindowStores treeViewInf chronViewInf runListInf = do
  treeModel    <- treeStoreNew []
  chronModel   <- listStoreNew []
  runModel     <- listStoreNew []
  -- Set up column bindings.
  let makeCol info model (getCol, getText) =
          setupTextColumn (getCol info) model
                          (\row -> [cellText := getText row])
      treeCols   = [(treeViewText,         entryColumnText),
                    (treeViewNumChoices,   entryColumnNumChoices),
                    (treeViewBrokenDeps,   entryColumnBrokenDeps),
                    (treeViewStepNum,      entryColumnStepNum),
                    (treeViewChildren,     entryColumnChildren),
                    (treeViewHeight,       entryColumnHeight),
                    (treeViewSubtreeSize,  entryColumnSubtreeSize),
                    (treeViewTier,         entryColumnTier),
                    (treeViewScore,        entryColumnScore)]
      chronCols  = [(chronViewNumChoices,  show . chronNumChoices),
                    (chronViewBrokenDeps,  show . chronBrokenDeps),
                    (chronViewStepNum,     show . chronStepNum),
                    (chronViewChildren,    show . chronChildren),
                    (chronViewHeight,      show . chronHeight),
                    (chronViewSubtreeSize, show . chronSubtreeSize),
                    (chronViewTier,        show . chronTier),
                    (chronViewScore,       show . chronScore)]
      runCols = [(runListNumber,     show . fst),
                 (runListLength,     show . length . snd)]
  mapM_ (makeCol treeViewInf treeModel) treeCols
  mapM_ (makeCol chronViewInf chronModel) chronCols
  mapM_ (makeCol runListInf runModel) runCols
  return (treeModel, chronModel, runModel)

treeSelectionChanged :: VisualizeContext -> TreeSelection -> TreeViewStore -> IO ()
treeSelectionChanged ctx selection model = do
  num <- treeSelectionCountSelectedRows selection
  (if num /= 1
   then runVis (stepSelected Nothing) ctx
   else do (Just selected) <- treeSelectionGetSelected selection
           path            <- treeModelGetPath model selected
           node            <- treeStoreLookup model path
           (case node of
              Nothing   -> runVis (stepSelected Nothing) ctx
              Just (Node {rootLabel = Root {entryStep = step}}) -> runVis (stepSelected (Just step)) ctx
              Just (Node {rootLabel = Step {entryStep = step}}) -> runVis (stepSelected (Just step)) ctx
              Just (Node {rootLabel = AlreadyGeneratedStep { entryTextStart  = start,
                                                             entryTextLength = len }})
                  -> runVis (showText start len) ctx
              _ -> runVis (stepSelected Nothing) ctx))

chronSelectionChanged :: VisualizeContext -> TreeSelection -> ChronViewStore -> IO ()
chronSelectionChanged ctx selection model = do
  num <- treeSelectionCountSelectedRows selection
  (if num /= 1
   then runVis (stepSelected Nothing) ctx
   else do (Just selected) <- treeSelectionGetSelected selection
           (i:_)           <- treeModelGetPath model selected
           entry           <- listStoreGetValue model i
           runVis (stepSelected $ Just $ chronStep entry) ctx)

runSelectionChanged :: VisualizeContext -> TreeSelection -> RunListStore -> IO ()
runSelectionChanged ctx selection model = do
  num <- treeSelectionCountSelectedRows selection
  (if num /= 1
   then runVis (setRun Nothing) ctx
   else do (Just selected) <- treeSelectionGetSelected selection
           (i:_) <- treeModelGetPath model selected
           run <- listStoreGetValue model  i
           runVis (setRun (Just run)) ctx)

newCtx :: GladeXML -> Params -> MainM VisualizeContext
newCtx xml params =
    do mainCtx <- ask
       (treeViewColInf, chronViewColumnInf, runListColumnInf) <- createMainWindowColumns xml
       liftIO $ do sourceView <- setupMainWindow xml
                   treeView <- xmlGetWidget xml castToTreeView "tree_view_search_tree"
                   chronView <- xmlGetWidget xml castToTreeView "tree_view_search_history"
                   runView <- xmlGetWidget xml castToTreeView "tree_view_run_list"
                   mapM_ (treeViewAppendColumn treeView)      (treeViewColumnInfoColumns treeViewColInf)
                   mapM_ (treeViewAppendColumn chronView)     (chronViewColumnInfoColumns chronViewColumnInf)
                   mapM_ (treeViewAppendColumn runView)   (runListInfoColumns runListColumnInf)
                   (treeModel, chronModel, runModel) <-
                       createMainWindowStores treeViewColInf chronViewColumnInf runListColumnInf

                   lf <- newIORef Nothing
                   runRef <- newIORef Nothing

                   let ctx = VisualizeContext { treeView = treeView,
                                                treeViewColumnInfo = treeViewColInf,
                                                treeViewStore = treeModel,
                                                chronologicalView = chronView,
                                                chronologicalViewColumnInfo = chronViewColumnInf,
                                                chronologicalViewStore = chronModel,
                                                runList = runView,
                                                runListColumnInfo = runListColumnInf,
                                                runListStore = runModel,
                                                logView = sourceView,
                                                loadedFile = lf,
                                                params = params,
                                                activeRun = runRef,
                                                mainContext = mainCtx }

                   treeSelection <- treeViewGetSelection treeView
                   treeSelectionSetMode treeSelection SelectionSingle
                   afterSelectionChanged treeSelection (treeSelectionChanged ctx treeSelection treeModel)

                   chronSelection <- treeViewGetSelection chronView
                   treeSelectionSetMode chronSelection SelectionSingle
                   afterSelectionChanged chronSelection (chronSelectionChanged ctx chronSelection chronModel)

                   runSelection <- treeViewGetSelection runView
                   treeSelectionSetMode runSelection SelectionSingle
                   afterSelectionChanged runSelection (runSelectionChanged ctx runSelection runModel)

                   treeViewSetModel treeView treeModel
                   treeViewSetModel chronView chronModel
                   treeViewSetModel runView runModel
                   return ctx



newMainWindow :: Params -> MainM (GladeXML, VisualizeContext)
newMainWindow params =
    do mainContext <- ask
       (xml, mainWindow) <- liftIO $ loadMainWindowXML
       ctx <- newCtx xml params
       mainWindowOpened
       liftIO $ on mainWindow deleteEvent (liftIO $ doMainWindowClosed mainContext)
       return (xml, ctx)
    where doMainWindowClosed mainContext = do runMain mainWindowClosed mainContext
                                              return True

milliToPicoseconds n = n * 1000000000

-- | Load the given log file in a background thread, displaying the
-- progress in the foreground thread.  When it's done, pop up a new
-- main window.
--
-- TODO: support displaying in an existing main window.
load :: Params -> FilePath -> MainM ()
load params fn =
    do loadedFile <- liftIO $ do (xml, win)  <- loadLoadingProgressXML
                                 title       <- xmlGetWidget xml castToLabel "label_title"
                                 progressBar <- xmlGetWidget xml castToProgressBar "load_progress"
                                 status      <- xmlGetWidget xml castToLabel "label_statistics"
                                 -- Should be done in a separate thread but GHC/Gtk2HS
                                 -- suck for threaded GUI programming.  See
                                 --
                                 -- http://haskell.org/gtk2hs/archives/2005/07/24/writing-multi-threaded-guis/1/
                                 --
                                 -- for (very gory) details.
                                 labelSetText title ("Loading " ++ fn ++ "...")
                                 widgetShow win
                                 h   <- openFile fn ReadMode
                                 lastTime <- newIORef Nothing
                                 log <- loadLogFile h fn (showProgress progressBar lastTime)
                                 widgetDestroy win
                                 return log
       (xml, ctx) <- newMainWindow params
       liftIO $ runVis (setLog loadedFile) ctx
       liftIO $ xmlGetWidget xml castToWindow "main_window" >>= widgetShowAll
       return ()
    where showProgress :: ProgressBar -> IORef (Maybe ClockTime) -> Integer -> Integer -> IO ()
          showProgress pb lastTime cur max =
              do oldf     <- progressBarGetFraction pb
                 currTime <- getClockTime
                 last     <- readIORef lastTime
                 writeIORef lastTime (Just currTime)
                 let updateInterval = TimeDiff { tdYear = 0,
                                                 tdMonth = 0,
                                                 tdDay = 0,
                                                 tdHour = 0,
                                                 tdMin = 0,
                                                 tdSec = 0,
                                                 tdPicosec = milliToPicoseconds 100 }
                     newf           = if max == 0 then 0 else ((fromInteger cur) / (fromInteger max))
                     longUpdate     = case last of
                                        Nothing -> True
                                        Just time -> diffClockTimes currTime time >= updateInterval
                     shouldUpdate   = longUpdate || newf == 1
                 when shouldUpdate (do progressBarSetFraction pb newf
                                       progressBarSetText pb (showFFloat (Just 1) (100 * newf) "" ++ "%")
                                       while (mainContextIteration mainContextDefault False) (return ()) ()
                                       return ())

filterUserParams :: [String] -> Params -> ([String], Params)
filterUserParams [] params = ([], params)
filterUserParams ("--max-steps":(n:args)) params = let params' = params { maxSteps = Just $ read n } in
                                                   filterUserParams args params'
filterUserParams ("--first-step":(n:args)) params = let params' = params { firstStep = Just $ read n } in
                                                    filterUserParams args params'
filterUserParams ("--dot-output":(fn:args)) params = let params' = params { dotOutput = Just $ fn } in
                                                     filterUserParams args params'
filterUserParams (arg:args) params = let (args', params') = filterUserParams args params in
                                     (arg:args', params')

textProgress :: IORef Integer -> Integer -> Integer -> IO ()
textProgress ref cur max =
    do lastPercent <- readIORef ref
       (if cur >= (max * (lastPercent + 10) `div` 100)
        then do let newPercent = lastPercent + 10
                print newPercent
                writeIORef ref newPercent
        else return ())

makeTextProgress :: IO (Integer -> Integer -> IO ())
makeTextProgress = do ref <- newIORef 0
                      return $ textProgress ref

inBounds :: Params -> Integer -> Bool
inBounds params n = let first = maybe 0 id (firstStep params) in
                    n >= first && maybe True (\max -> n < first + max) (maxSteps params)

dotChoiceLabel :: LinkChoice -> String
dotChoiceLabel lc@(LinkChoice c) = choiceText lc
dotChoiceLabel Unknown           = ""

dotStepNode :: Params -> ProcessingStep -> Node
dotStepNode params step = let n = node (name $ printf "step%d" (stepOrder step))
                                  ..= ("label", printf "Step: %d\nScore: %d\nTier: %s"
                                                  (stepOrder step)
                                                  (solScore $ stepSol step)
                                                  (show $ solTier $ stepSol step)) in
                          if Set.null $ solBrokenDeps (stepSol step)
                          then n ..= ("style", "filled")
                                 ..= ("fillecolor", "lightgrey")
                          else n

-- Generate nodes for any successors that were not processed in the
-- render.
dotUnprocessedSuccs :: Params -> ProcessingStep -> [Node]
dotUnprocessedSuccs params step = unprocessed ++ excluded
    where unprocessed = [ let n = node (name $ printf "step%dunproc%d" (stepOrder step) stepNum)
                                  ..= ("label", printf "Unprocessed\nScore: %d\nTier: %s"
                                                  (solScore succSol)
                                                  (show $ solTier succSol)) in
                          if Set.null $ solBrokenDeps (stepSol step)
                          then n ..= ("style", "dashed,filled")
                                 ..= ("fillcolor", "lightgrey")
                          else n ..= ("style", "dashed")
                          | ((Unprocessed { successorChoice    = succChoice,
                                            successorSolution  = succSol }),
                             stepNum)
                          <- zip (stepSuccessors step) ([0..] :: [Integer]) ]
          excluded    = [ node (name $ printf "step%d" (stepOrder step))
                                   ..= ("label", printf "%d nodes..." (stepBranchSize step))
                                   ..= ("shape", "plaintext")
                                   ..= ("image", "cloud.png")
                          | (Successor { successorStep = step }) <- stepSuccessors step,
                            not $ inBounds params (stepOrder step) ]

dotEdges params step = processed ++ unprocessed
    where processed   = [ edge (node (name $ printf "step%d" (stepOrder step)))
                               (node (name $ printf "step%d" (stepOrder step')))
                          ..= ("label", dotChoiceLabel succChoice)
                          | Successor { successorStep   = step',
                                        successorChoice = succChoice } <- stepSuccessors step ]
          unprocessed = [ edge (node (name $ printf "step%d" (stepOrder step)))
                               (node (name $ printf "step%dunproc%d" (stepOrder step) stepNum))
                          ..= ("label", dotChoiceLabel succChoice)
                          | ((Unprocessed { successorChoice = succChoice }), stepNum)
                              <- zip (stepSuccessors step) ([0..] :: [Integer]) ]

renderDot :: Params -> [ProcessingStep] -> Digraph
renderDot params steps =
    let droppedSteps   = maybe steps (\n -> genericDrop n steps) (firstStep params)
        truncatedSteps = maybe steps (\n -> genericTake n steps) (maxSteps params) in
    if null truncatedSteps
    then error "No steps to render."
    else let stepNodes          = map (dotStepNode params) truncatedSteps
             unprocessed        = concat $ map (dotUnprocessedSuccs params) truncatedSteps
             edges              = concat $ map (dotEdges params) truncatedSteps in
         digraph (stepNodes ++ unprocessed) edges

writeDotRun params steps outputFile =
    do let dot = renderDot params steps
       withFile outputFile WriteMode $ \h ->
           hPutStrLn h (show dot)

writeDotOutput params logFile outputFile =
    -- TODO: show progress better.
    do progress <- makeTextProgress
       withFile logFile ReadMode $ \h ->
           do log <- loadLogFile h logFile progress
              (if null $ runs log
               then return ()
               else if (null (drop 1 $ runs log))
                    then writeDotRun params (head $ runs log) outputFile
                    else sequence_ [ writeDotRun params steps (printf "%s-%d" outputFile n)
                                         | (steps, n) <- zip (runs log) ([1..] :: [Integer]) ])

main :: IO ()
main = do -- Gtk2Hs whines loudly if it gets loaded into a threaded
          -- runtime, but runhaskell always loads a threaded runtime,
          -- so we have to call this to be a script:
          unsafeInitGUIForThreadedRTS
          mainWindows <- newIORef 0
          mainLoop <- mainLoopNew Nothing False
          let mainLoopContext = MainLoopContext { numMainWindows = mainWindows,
                                                  mainLoop = mainLoop }
          args <- getArgs
          let (args', params) = filterUserParams args defaultParams
          case args' of
            [] -> do (xml, ctx) <- runMain (newMainWindow params) mainLoopContext
                     mainWin <- xmlGetWidget xml castToWindow "main_window"
                     widgetShow (toWidget mainWin)
                     mainLoopRun mainLoop
            [filename] ->
                case params of
                  Params { dotOutput = Just output } -> writeDotOutput params filename output
                  _ -> runMain (load params filename) mainLoopContext >> mainLoopRun mainLoop
            otherwise -> error "Too many arguments; expected at most one (the log file to load)."