#include "../include/ast.h"
#include "../include/parser.h"
#include "../include/std/log.h"
#include "../include/std/hash.h"
#include <assert.h>

#define throw(result) do { longjmp(context->env, (result)); } while(0)
#define throw_if_error(result) \
do { \
    int return_if_result; \
    return_if_result = (result); \
    if((return_if_result) != 0) \
        throw(return_if_result); \
} while(0)

static void ast_resolve(Ast *self, AstCompilerContext *context);

Ast ast_none() {
    Ast ast;
    ast.value.func_decl = NULL;
    ast.type = AST_NONE;
    ast.resolve_status = AST_NOT_RESOLVED;
    ast.resolved_type = NULL;
    return ast;
}

void ast_init(Ast *self, void *value, AstType type) {
    self->value.data = value;
    self->type = type;
    self->resolve_status = AST_NOT_RESOLVED;
    self->resolved_type = NULL;
}

BufferView ast_get_name(Ast *self) {
    BufferView name;
    switch(self->type) {
        case AST_NONE:
        case AST_FUNCTION_DECL:
        case AST_STRUCT_DECL:
        case AST_IMPORT:
        case AST_STRING:
        case AST_NUMBER:
        case AST_BINOP:
            name = create_buffer_view_null();
            break;
        case AST_LHS:
            name = self->value.lhs_expr->var_name;
            break;
        case AST_FUNCTION_CALL:
            name = self->value.func_call->func.name;
            break;
        case AST_VARIABLE:
            name = self->value.variable->name;
            break;
        case AST_STRUCT_FIELD:
            name = self->value.struct_field->name;
            break;
    }
    return name;
}

static BufferView ast_get_code_reference(Ast *self) {
    return ast_get_name(self);
}

int funcdecl_init(FunctionDecl *self, Scope *parent, ScopedAllocator *allocator) {
    self->ssa_func_index = 0;
    return scope_init(&self->body, parent, allocator);
}

int funccall_init(FunctionCall *self, BufferView name, ScopedAllocator *allocator) {
    variable_init(&self->func, name);
    return buffer_init(&self->args, allocator);
}

int structdecl_init(StructDecl *self, Scope *parent, ScopedAllocator *allocator) {
    return scope_init(&self->body, parent, allocator);
}

void structfield_init(StructField *self, BufferView name, BufferView type_name) {
    self->name = name;
    variable_init(&self->type, type_name);
}

void lhsexpr_init(LhsExpr *self, bool is_pub, bool is_const, BufferView var_name) {
    self->is_pub = is_pub;
    self->is_const = is_const;
    variable_init(&self->type, create_buffer_view_null());
    self->var_name = var_name;
    self->rhs_expr = ast_none();
}

void import_init(Import *self, BufferView path) {
    self->path = path;
    self->file_scope = NULL;
}

int string_init(String *self, BufferView str) {
    /* TODO: Convert special characters. For example \n should be converted to binary newline etc */
    self->str = str;
    return 0;
}

void number_init(Number *self, i64 value, bool is_integer) {
    self->value.integer = value;
    self->is_integer = is_integer;
}

void variable_init(Variable *self, BufferView name) {
    self->name = name;
}

void binop_init(Binop *self) {
    self->lhs = ast_none();
    self->rhs = ast_none();
    self->type = BINOP_ADD;
    self->grouped = bool_false;
}

int scope_init(Scope *self, Scope *parent, ScopedAllocator *allocator) {
    return_if_error(buffer_init(&self->ast_objects, allocator));
    return_if_error(hash_map_init(&self->named_objects, allocator, sizeof(Ast), hash_compare_string, amal_hash_string));
    self->parent = parent;
    return 0;
}

int file_scope_reference_init(FileScopeReference *self, BufferView canonical_path, ScopedAllocator *allocator) {
    char null_terminator;
    null_terminator = '\0';
    self->scope = NULL;

    return_if_error(buffer_init(&self->canonical_path, allocator));
    return_if_error(buffer_append(&self->canonical_path, canonical_path.data, canonical_path.size));
    return_if_error(buffer_append(&self->canonical_path, &null_terminator, 1));
    /* To exclude null-terminator character from size but not from data */
    self->canonical_path.size -= 1;
    return 0;
}

int scope_add_child(Scope *self, Ast *child) {
    Ast existing_child;
    bool child_already_exists;

    /* TODO: Implement for parameter */
    if(child->type == AST_LHS) {
        BufferView var_name;
        var_name = child->value.lhs_expr->var_name;
        child_already_exists = hash_map_get(&self->named_objects, var_name, &existing_child);
        if(child_already_exists)
            return AST_ERR_DEF_DUP;

        cleanup_if_error(hash_map_insert(&self->named_objects, var_name, child));
    }
    cleanup_if_error(buffer_append(&self->ast_objects, child, sizeof(Ast)));
    return 0;

    cleanup:
    return AST_ERR;
}

void scope_resolve(Scope *self, AstCompilerContext *context) {
    Ast *ast;
    Ast *ast_end;

    ast = buffer_start(&self->ast_objects);
    ast_end = buffer_end(&self->ast_objects);
    context->scope = self;
    for(; ast != ast_end; ++ast) {
        ast_resolve(ast, context);
    }
    context->scope = self->parent;
}

static LhsExpr* scope_get_resolved_variable(Scope *self, AstCompilerContext *context, BufferView name) {
    Ast result;
    bool exists;
    Scope *prev_scope;

    assert(self);
    exists = hash_map_get(&self->named_objects, name, &result);
    if(!exists) {
        if(self->parent)
            return scope_get_resolved_variable(self->parent, context, name);

        tokenizer_print_error(&context->parser->tokenizer,
                              tokenizer_get_code_reference_index(&context->parser->tokenizer, name.data),
                              "Undefined reference to variable \"%.*s\"", name.size, name.data);
        throw(AST_ERR);
    }

    /*
    Need to change scope here because we are changing the visible scope
    and the ast object may be in another scope than the current 
    resolving ast.
    */
    prev_scope = context->scope;
    context->scope = self;
    ast_resolve(&result, context);
    context->scope = prev_scope;

    assert(result.type == AST_LHS);
    return result.value.lhs_expr;
}

/* @resolved_type is the same field as the ast resolved_type for the variable @self */
static void variable_resolve(Variable *self, AstCompilerContext *context, LhsExpr **resolved_type) {
    /* TODO: Verify this is correct in all cases */
    *resolved_type = scope_get_resolved_variable(context->scope, context, self->name);
}

static void lhs_resolve(Ast *self, AstCompilerContext *context) {
    LhsExpr *lhs_expr;
    lhs_expr = self->value.lhs_expr;

    if(lhs_expr->type.name.data)
        variable_resolve(&lhs_expr->type, context, &self->resolved_type);
    self->resolve_status = AST_RESOLVED;
    ast_resolve(&lhs_expr->rhs_expr, context);

    if(self->resolved_type &&
       lhs_expr->rhs_expr.type != AST_NONE &&
       self->resolved_type != lhs_expr->rhs_expr.resolved_type) {
        tokenizer_print_error(&context->parser->tokenizer,
                              tokenizer_get_code_reference_index(&context->parser->tokenizer, ast_get_code_reference(self).data),
                              "Variable type and variable assignment type (right-hand side) do not match");
        throw(AST_ERR);
    }
    self->resolved_type = lhs_expr->rhs_expr.resolved_type;
}

static void import_resolve(Ast *self, AstCompilerContext *context) {
    Import *import;
    import = self->value.import;
    (void)import;
    (void)self;
    (void)context;
    /* TODO: Convert all scopes to structs and set import->resolved_type to import->file_scope->scope; */
}

static void funcdecl_resolve(Ast *self, AstCompilerContext *context) {
    /* TODO: Implement */
    FunctionDecl *func_decl;
    assert(self->type == AST_FUNCTION_DECL);
    func_decl = self->value.func_decl;
    self->resolve_status = AST_RESOLVED;
    scope_resolve(&func_decl->body, context);
}

static void funccall_resolve(Ast *self, AstCompilerContext *context) {
    FunctionCall *func_call;
    Ast *ast;
    Ast *ast_end;

    func_call = self->value.func_call;
    variable_resolve(&func_call->func, context, &self->resolved_type);

    ast = buffer_start(&func_call->args);
    ast_end = buffer_end(&func_call->args);
    for(; ast != ast_end; ++ast) {
        ast_resolve(ast, context);
    }
}

static void structdecl_resolve(Ast *self, AstCompilerContext *context) {
    /* TODO: What to do with resolved_type? */
    StructDecl *struct_decl;
    struct_decl = self->value.struct_decl;
    scope_resolve(&struct_decl->body, context);
}

static void structfield_resolve(Ast *self, AstCompilerContext *context) {
    /* TODO: Implement */
    StructField *struct_field;
    struct_field = self->value.struct_field;
    variable_resolve(&struct_field->type, context, &self->resolved_type);
}

static void binop_resolve(Binop *self, AstCompilerContext *context) {
    /* TODO: Implement */
    ast_resolve(&self->lhs, context);
    ast_resolve(&self->rhs, context);
}

void ast_resolve(Ast *self, AstCompilerContext *context) {
    /* 
    TODO: Move these to the types that need checks for recursive dependency (function declaration, struct declaration)
    For function declaration, it should be marked as resolved when the signature has been resolved
    instead of the whole function declaration including the body
    because the body can have function call that calls functions that are resolving
    or even recursive function call, which should be allowed.
    */
    if(self->resolve_status == AST_RESOLVED) {
        return;
    } else if(self->resolve_status == AST_RESOLVING) {
        tokenizer_print_error(&context->parser->tokenizer,
                              tokenizer_get_code_reference_index(&context->parser->tokenizer, ast_get_code_reference(self).data),
                              "Found recursive dependency");
        throw(AST_ERR);
    }

    self->resolve_status = AST_RESOLVING;
    switch(self->type) {
        case AST_NONE:
        case AST_NUMBER:
            /* Nothing to resolve for numbers */
            break;
        case AST_FUNCTION_DECL:
            funcdecl_resolve(self, context);
            break;
        case AST_FUNCTION_CALL:
            funccall_resolve(self, context);
            break;
        case AST_STRUCT_DECL:
            structdecl_resolve(self, context);
            break;
        case AST_STRUCT_FIELD:
            structfield_resolve(self, context);
            break;
        case AST_LHS:
            lhs_resolve(self, context);
            break;
        case AST_IMPORT:
            /* TODO: When @import(...).data syntax is added, implement the resolve for it */
            import_resolve(self, context);
            break;
        case AST_STRING:
            /* TODO: Convert special combinations. For example \n to newline */
            break;
        case AST_VARIABLE:
            variable_resolve(self->value.variable, context, &self->resolved_type);
            break;
        case AST_BINOP:
            binop_resolve(self->value.binop, context);
            break;
    }
    /* TODO: See comment at the top of this function */
    self->resolve_status = AST_RESOLVED;
}