/**
 */
#include "ast_iterate.hpp"
#include "../ast/ast.hpp"

void CASTIterator::handle_path(AST::Path& path, CASTIterator::PathMode pm)
{
}
void CASTIterator::handle_type(TypeRef& type)
{
    //DEBUG("type = " << type);
    if( type.is_path() )
    {
        handle_path(type.path(), MODE_TYPE);
    }
    else
    {
        for(auto& subtype : type.sub_types())
            handle_type(subtype);
    }
}
void CASTIterator::handle_expr(AST::ExprNode& node)
{
}
void CASTIterator::handle_params(AST::TypeParams& params)
{
    DEBUG("params");
    for( auto& param : params.ty_params() )
    {
        handle_type(param.get_default());
        local_type( param.name(), TypeRef(TypeRef::TagArg(), param.name(), params) );
    }
    DEBUG("Bounds");
    for( auto& bound : params.bounds() )
    {
        handle_type(bound.test());
        if( !bound.is_trait() )
            DEBUG("namecheck lifetime bounds?");
        else
            handle_path(bound.bound(), CASTIterator::MODE_TYPE);
    }
}


void CASTIterator::start_scope()
{
    INDENT();
}
void CASTIterator::local_type(::std::string name, TypeRef type)
{
    DEBUG("type " << name << " = " << type);
}
void CASTIterator::local_variable(bool is_mut, ::std::string name, const TypeRef& type)
{
    DEBUG( (is_mut ? "mut " : "") << name << " : " << type );
}
void CASTIterator::local_use(::std::string name, AST::Path path)
{
    DEBUG( name << " = " << path );
}
void CASTIterator::end_scope()
{
    UNINDENT();
}

void CASTIterator::handle_pattern(AST::Pattern& pat, const TypeRef& type_hint)
{
    //DEBUG("pat = " << pat);
    // Resolve names
    switch(pat.data().tag())
    {
    case AST::Pattern::Data::Any:
        // Wildcard, nothing to do
        break;
    case AST::Pattern::Data::Ref: {
        auto& v = pat.data().as_Ref();
        if( type_hint.is_wildcard() )
            handle_pattern(*v.sub, (const TypeRef&)TypeRef());
        else if( !type_hint.is_reference() )
            throw ::std::runtime_error( FMT("Ref pattern on non-ref value: " << type_hint) );
        else
            handle_pattern(*v.sub, type_hint.sub_types()[0]);
        break; }
    case AST::Pattern::Data::MaybeBind:
        throw ::std::runtime_error("Calling CASTIterator::handle_pattern on MAYBE_BIND, not valid");
    case AST::Pattern::Data::Value: {
        auto& v = pat.data().as_Value();
        handle_expr( *v.start );
        if( v.end.get() )
            handle_expr( *v.end );
        break; }
    case AST::Pattern::Data::Tuple: {
        auto& v = pat.data().as_Tuple();
        // Tuple is handled by subpattern code
        if( type_hint.is_wildcard() )
        {
            for( auto& sp : v.sub_patterns )
                handle_pattern(sp, (const TypeRef&)TypeRef());
        }
        else if( !type_hint.is_tuple() )
        {
            throw ::std::runtime_error("Tuple pattern on non-tuple value");
        }
        else
        {
            if( type_hint.sub_types().size() != v.sub_patterns.size() )
            {
                throw ::std::runtime_error("Tuple pattern count doesn't match");
            }
            for( unsigned int i = 0; i < v.sub_patterns.size(); i ++ )
            {
                handle_pattern(v.sub_patterns[i], type_hint.sub_types()[i]);
            }
        }
        break; }
    case AST::Pattern::Data::Struct: {
        auto& v = pat.data().as_Struct();
        handle_path( v.path, CASTIterator::MODE_TYPE );
        if( type_hint.is_wildcard() )
        {
            for( auto& sp : v.sub_patterns )
                handle_pattern(sp.second, (const TypeRef&)TypeRef());
        }
        else if( !type_hint.is_path() )
        {
            throw ::std::runtime_error("Tuple struct pattern on non-tuple value");
        }
        else
        {
            throw ::std::runtime_error("TODO: Struct typecheck/iterate");
        }
        break; }
    case AST::Pattern::Data::StructTuple: {
        auto& v = pat.data().as_StructTuple();
        // Resolve the path!
        handle_path( v.path, CASTIterator::MODE_TYPE );
        // Handle sub-patterns
        if( type_hint.is_wildcard() )
        {
            for( auto& sp : v.sub_patterns )
                handle_pattern(sp, (const TypeRef&)TypeRef());
        }
        else if( !type_hint.is_path() )
        {
            throw ::std::runtime_error("Tuple struct pattern on non-tuple value");
        }
        else
        {
            auto& hint_path = type_hint.path();
            auto& pat_path = v.path;
            const auto& hint_binding = hint_path.binding();
            const auto& pat_binding = pat_path.binding();
            DEBUG("Pat: " << pat_path << ", Type: " << type_hint.path());
            switch( hint_binding.type() )
            {
            case AST::PathBinding::UNBOUND:
                throw ::std::runtime_error("Unbound path in pattern");
            case AST::PathBinding::ENUM: {
                // The pattern's path must refer to a variant of the hint path
                // - Actual type params are checked by the 'handle_pattern_enum' code
                if( pat_binding.type() != AST::PathBinding::ENUM_VAR )
                    throw ::std::runtime_error(FMT("Paths in pattern are invalid"));
                if( pat_binding.bound_enumvar().enum_ != &hint_binding.bound_enum() )
                    throw ::std::runtime_error(FMT("Paths in pattern are invalid"));
                const auto& enm = *pat_binding.bound_enumvar().enum_;
                auto idx = pat_binding.bound_enumvar().idx;
                auto& var = enm.variants().at(idx);
                handle_pattern_enum(pat_path[-2].args(), hint_path[-1].args(), enm.params(), var, v.sub_patterns);
                break; }
            default:
                throw ::std::runtime_error(FMT("Bad type in tuple struct pattern : " << type_hint.path()));
            }
        }
        break; }
    }
    // Extract bindings and add to namespace
    if( pat.binding().size() > 0 )
    {
        // TODO: Mutable bindings
        if(pat.binding() != "_")
        {
            local_variable( false, pat.binding(), type_hint );
        }
    }
}
void CASTIterator::handle_pattern_enum(
        ::std::vector<TypeRef>& pat_args, const ::std::vector<TypeRef>& hint_args,
        const AST::TypeParams& enum_params, const AST::EnumVariant& var,
        ::std::vector<AST::Pattern>& sub_patterns
        )
{
    // This implementation doesn't attempt to do anything with types, just propagates _
    for( auto& sp : sub_patterns )
        handle_pattern(sp, (const TypeRef&)TypeRef());
}

void CASTIterator::handle_module(AST::Path path, AST::Module& mod)
{
    INDENT();
    start_scope();
    
    for( auto& item : mod.structs() )
    {
        DEBUG("Handling struct " << item.name);
        handle_struct(path + item.name, item.data);
    }
    for( auto& item : mod.enums() )
    {
        DEBUG("Handling enum " << item.name);
        handle_enum(path + item.name, item.data);
    }
    for( auto& item : mod.traits() )
    {
        DEBUG("Handling trait " << item.name);
        handle_trait(path + item.name, item.data);
    }
    for( auto& item : mod.type_aliases() )
    {
        DEBUG("Handling alias " << item.name);
        handle_alias(path + item.name, item.data);
    }
    for( auto& stat : mod.statics() )
    {
        DEBUG("handling static " << stat.name);
        handle_type(stat.data.type());
        handle_expr(stat.data.value().node());
    }
    
    for( auto& fcn : mod.functions() )
    {
        DEBUG("Handling function '" << fcn.name << "'");
        handle_function(path + fcn.name, fcn.data);
    }
    for( auto& impl : mod.impls() )
    {
        DEBUG("Handling 'impl' " << impl);
        handle_impl(path, impl);
    }
    
    // End scope before handling sub-modules
    end_scope(); 
 
    for( auto& submod : mod.submods() )
    {
        DEBUG("Handling submod '" << submod.first.name() << "'");
        handle_module(path + submod.first.name(), submod.first);
    }
    UNINDENT();
}
void CASTIterator::handle_function(AST::Path path, AST::Function& fcn)
{
    TRACE_FUNCTION_F("path = " << path << ", fcn.params() = " << fcn.params());
    start_scope();
    
    DEBUG("params");
    handle_params(fcn.params());
    
    DEBUG("ret type");
    handle_type(fcn.rettype());
    
    DEBUG("args");
    for( auto& arg : fcn.args() )
    {
        handle_type(arg.second);
        // TODO: Check if pattern is irrefutable?
        handle_pattern( arg.first, arg.second );
    }

    DEBUG("code");
    if( fcn.code().is_valid() )
    {
        INDENT();
        handle_expr( fcn.code().node() );
        UNINDENT();
    }
    
    end_scope();
}

void CASTIterator::handle_impl_def(AST::ImplDef& impl)
{
    // First, so that handle_params can use it
    local_type("Self", impl.type());
    
    // Generic params
    handle_params( impl.params() );
    
    // Trait
    if( impl.trait() != AST::Path() )
        handle_path( impl.trait(), MODE_TYPE );
    // Type
    handle_type( impl.type() );
}

void CASTIterator::handle_impl(AST::Path modpath, AST::Impl& impl)
{
    start_scope();
    
    handle_impl_def(impl.def());   
    
    // Associated types
    for( auto& at : impl.types() )
    {
        DEBUG("- Type '" << at.name << "'");
        handle_type( at.data );
    }
    
    // Functions
    for( auto& fcn : impl.functions() )
    {
        DEBUG("- Function '" << fcn.name << "'");
        handle_function(AST::Path() + fcn.name, fcn.data);
    }
    
    end_scope();
}

void CASTIterator::handle_struct(AST::Path path, AST::Struct& str)
{
    start_scope();
    handle_params( str.params() );
    for( auto& f : str.fields() )
        handle_type( f.data );
    end_scope();
}
void CASTIterator::handle_enum(AST::Path path, AST::Enum& enm)
{
    start_scope();
    handle_params( enm.params() );
    for( auto& f : enm.variants() )
    {
        for( auto& t : f.m_sub_types )
            handle_type(t);
    }
    end_scope();
}
void CASTIterator::handle_trait(AST::Path path, AST::Trait& trait)
{
    start_scope();
    local_type("Self", TypeRef(TypeRef::TagArg(), "Self"));
    handle_params( trait.params() );
    
    //local_type("Self", TypeRef(path));
    //local_type("Self", TypeRef(TypeRef::TagArg(), "Self"));
    
    for( auto& fcn : trait.functions() )
        handle_function( path + fcn.name, fcn.data );
    end_scope();
}
void CASTIterator::handle_alias(AST::Path path, AST::TypeAlias& alias)
{
    start_scope();
    handle_params( alias.params() );
    handle_type( alias.type() );
    end_scope();
}