#define _POSIX_C_SOURCE 200809L
#include "parser.h"
#include <stdlib.h>
#include <string.h>

extern void _rava_parser_advance(RavaParser_t *parser);
extern bool _rava_parser_check(RavaParser_t *parser, RavaTokenType_e type);
extern bool _rava_parser_match(RavaParser_t *parser, RavaTokenType_e type);
extern bool _rava_parser_expect(RavaParser_t *parser, RavaTokenType_e type, const char *message);
extern RavaASTNode_t* _rava_parser_parse_type(RavaParser_t *parser);
extern RavaASTNode_t* _rava_parser_parse_expression(RavaParser_t *parser);
extern RavaASTNode_t* _rava_parser_parse_block(RavaParser_t *parser);
extern void _rava_parser_parse_modifiers(RavaParser_t *parser, RavaModifier_e **modifiers, size_t *count);

static RavaASTNode_t* _rava_parser_parse_method_declaration(RavaParser_t *parser,
                                                            RavaModifier_e *modifiers,
                                                            size_t modifiers_count,
                                                            RavaASTNode_t *return_type) {
    RavaASTNode_t *method = rava_ast_node_create(RAVA_AST_METHOD_DECL,
                                                 parser->current_token->line,
                                                 parser->current_token->column);

    method->data.method_decl.modifiers = modifiers;
    method->data.method_decl.modifiers_count = modifiers_count;
    method->data.method_decl.return_type = return_type;

    if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
        method->data.method_decl.name = strdup(parser->current_token->lexeme);
        _rava_parser_advance(parser);
    }

    _rava_parser_expect(parser, RAVA_TOKEN_LPAREN, "Expected '(' after method name");

    while (!_rava_parser_check(parser, RAVA_TOKEN_RPAREN) &&
           !_rava_parser_check(parser, RAVA_TOKEN_EOF)) {
        RavaASTNode_t *param_type = _rava_parser_parse_type(parser);
        RavaASTNode_t *param = rava_ast_node_create(RAVA_AST_PARAM_DECL,
                                                    parser->current_token->line,
                                                    parser->current_token->column);
        param->data.var_decl.type = param_type;

        if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
            param->data.var_decl.name = strdup(parser->current_token->lexeme);
            _rava_parser_advance(parser);
        }

        rava_ast_node_add_child(method, param);

        if (!_rava_parser_match(parser, RAVA_TOKEN_COMMA)) {
            break;
        }
    }

    _rava_parser_expect(parser, RAVA_TOKEN_RPAREN, "Expected ')' after parameters");

    if (_rava_parser_check(parser, RAVA_TOKEN_LBRACE)) {
        RavaASTNode_t *body = _rava_parser_parse_block(parser);
        rava_ast_node_add_child(method, body);
    } else {
        _rava_parser_expect(parser, RAVA_TOKEN_SEMICOLON, "Expected ';' or '{' after method declaration");
    }

    return method;
}

RavaASTNode_t* _rava_parser_parse_class_declaration(RavaParser_t *parser) {
    RavaModifier_e *modifiers = NULL;
    size_t modifiers_count = 0;

    _rava_parser_parse_modifiers(parser, &modifiers, &modifiers_count);

    _rava_parser_expect(parser, RAVA_TOKEN_KEYWORD_CLASS, "Expected 'class' keyword");

    RavaASTNode_t *class_decl = rava_ast_node_create(RAVA_AST_CLASS_DECL,
                                                     parser->current_token->line,
                                                     parser->current_token->column);

    class_decl->data.class_decl.modifiers = modifiers;
    class_decl->data.class_decl.modifiers_count = modifiers_count;
    class_decl->data.class_decl.superclass = NULL;
    class_decl->data.class_decl.interfaces = NULL;
    class_decl->data.class_decl.interfaces_count = 0;

    if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
        class_decl->data.class_decl.name = strdup(parser->current_token->lexeme);
        _rava_parser_advance(parser);
    }

    if (_rava_parser_match(parser, RAVA_TOKEN_KEYWORD_EXTENDS)) {
        if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
            class_decl->data.class_decl.superclass = strdup(parser->current_token->lexeme);
            _rava_parser_advance(parser);
        }
    }

    if (_rava_parser_match(parser, RAVA_TOKEN_KEYWORD_IMPLEMENTS)) {
        size_t capacity = 4;
        class_decl->data.class_decl.interfaces = malloc(capacity * sizeof(char*));
        do {
            if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
                if (class_decl->data.class_decl.interfaces_count >= capacity) {
                    capacity *= 2;
                    class_decl->data.class_decl.interfaces = realloc(
                        class_decl->data.class_decl.interfaces,
                        capacity * sizeof(char*));
                }
                class_decl->data.class_decl.interfaces[class_decl->data.class_decl.interfaces_count++] =
                    strdup(parser->current_token->lexeme);
                _rava_parser_advance(parser);
            }
        } while (_rava_parser_match(parser, RAVA_TOKEN_COMMA));
    }

    _rava_parser_expect(parser, RAVA_TOKEN_LBRACE, "Expected '{' after class name");

    while (!_rava_parser_check(parser, RAVA_TOKEN_RBRACE) &&
           !_rava_parser_check(parser, RAVA_TOKEN_EOF)) {

        RavaModifier_e *member_modifiers = NULL;
        size_t member_modifiers_count = 0;

        _rava_parser_parse_modifiers(parser, &member_modifiers, &member_modifiers_count);

        if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER) &&
            strcmp(parser->current_token->lexeme, class_decl->data.class_decl.name) == 0) {

            RavaASTNode_t *constructor = rava_ast_node_create(RAVA_AST_CONSTRUCTOR_DECL,
                                                              parser->current_token->line,
                                                              parser->current_token->column);
            _rava_parser_advance(parser);

            _rava_parser_expect(parser, RAVA_TOKEN_LPAREN, "Expected '(' after constructor name");

            while (!_rava_parser_check(parser, RAVA_TOKEN_RPAREN) &&
                   !_rava_parser_check(parser, RAVA_TOKEN_EOF)) {
                RavaASTNode_t *param_type = _rava_parser_parse_type(parser);
                RavaASTNode_t *param = rava_ast_node_create(RAVA_AST_PARAM_DECL,
                                                            parser->current_token->line,
                                                            parser->current_token->column);
                param->data.var_decl.type = param_type;

                if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
                    param->data.var_decl.name = strdup(parser->current_token->lexeme);
                    _rava_parser_advance(parser);
                }

                rava_ast_node_add_child(constructor, param);

                if (!_rava_parser_match(parser, RAVA_TOKEN_COMMA)) {
                    break;
                }
            }

            _rava_parser_expect(parser, RAVA_TOKEN_RPAREN, "Expected ')' after constructor parameters");

            if (_rava_parser_check(parser, RAVA_TOKEN_LBRACE)) {
                RavaASTNode_t *body = _rava_parser_parse_block(parser);
                rava_ast_node_add_child(constructor, body);
            }

            rava_ast_node_add_child(class_decl, constructor);
            free(member_modifiers);
            continue;
        }

        RavaASTNode_t *member_type = _rava_parser_parse_type(parser);

        if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
            char *name = strdup(parser->current_token->lexeme);
            _rava_parser_advance(parser);

            if (_rava_parser_check(parser, RAVA_TOKEN_LPAREN)) {
                RavaASTNode_t *method = _rava_parser_parse_method_declaration(parser,
                                                                              member_modifiers,
                                                                              member_modifiers_count,
                                                                              member_type);
                method->data.method_decl.name = name;
                rava_ast_node_add_child(class_decl, method);
            } else {
                RavaASTNode_t *field = rava_ast_node_create(RAVA_AST_FIELD_DECL,
                                                           parser->current_token->line,
                                                           parser->current_token->column);
                field->data.field_decl.type = member_type;
                field->data.field_decl.name = name;
                field->data.field_decl.modifiers = member_modifiers;
                field->data.field_decl.modifiers_count = member_modifiers_count;
                if (_rava_parser_match(parser, RAVA_TOKEN_ASSIGN)) {
                    field->data.field_decl.initializer = _rava_parser_parse_expression(parser);
                } else {
                    field->data.field_decl.initializer = NULL;
                }
                _rava_parser_expect(parser, RAVA_TOKEN_SEMICOLON, "Expected ';' after field declaration");
                rava_ast_node_add_child(class_decl, field);
                member_modifiers = NULL;
            }
        }
    }

    _rava_parser_expect(parser, RAVA_TOKEN_RBRACE, "Expected '}' after class body");

    return class_decl;
}

static RavaASTNode_t* _rava_parser_parse_interface_declaration(RavaParser_t *parser) {
    RavaModifier_e *modifiers = NULL;
    size_t modifiers_count = 0;

    _rava_parser_parse_modifiers(parser, &modifiers, &modifiers_count);

    _rava_parser_expect(parser, RAVA_TOKEN_KEYWORD_INTERFACE, "Expected 'interface' keyword");

    RavaASTNode_t *interface_decl = rava_ast_node_create(RAVA_AST_INTERFACE_DECL,
                                                         parser->current_token->line,
                                                         parser->current_token->column);

    interface_decl->data.interface_decl.modifiers = modifiers;
    interface_decl->data.interface_decl.modifiers_count = modifiers_count;

    if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
        interface_decl->data.interface_decl.name = strdup(parser->current_token->lexeme);
        _rava_parser_advance(parser);
    }

    _rava_parser_expect(parser, RAVA_TOKEN_LBRACE, "Expected '{' after interface name");

    while (!_rava_parser_check(parser, RAVA_TOKEN_RBRACE) &&
           !_rava_parser_check(parser, RAVA_TOKEN_EOF)) {

        RavaModifier_e *member_modifiers = NULL;
        size_t member_modifiers_count = 0;

        _rava_parser_parse_modifiers(parser, &member_modifiers, &member_modifiers_count);

        RavaASTNode_t *member_type = _rava_parser_parse_type(parser);

        if (_rava_parser_check(parser, RAVA_TOKEN_IDENTIFIER)) {
            char *name = strdup(parser->current_token->lexeme);
            _rava_parser_advance(parser);

            if (_rava_parser_check(parser, RAVA_TOKEN_LPAREN)) {
                RavaASTNode_t *method = _rava_parser_parse_method_declaration(parser,
                                                                              member_modifiers,
                                                                              member_modifiers_count,
                                                                              member_type);
                method->data.method_decl.name = name;
                rava_ast_node_add_child(interface_decl, method);
            } else {
                free(name);
                free(member_modifiers);
            }
        } else {
            free(member_modifiers);
        }
    }

    _rava_parser_expect(parser, RAVA_TOKEN_RBRACE, "Expected '}' after interface body");

    return interface_decl;
}

RavaASTNode_t* rava_parser_parse(RavaParser_t *parser) {
    RavaASTNode_t *root = rava_ast_node_create(RAVA_AST_COMPILATION_UNIT, 1, 1);

    while (!_rava_parser_check(parser, RAVA_TOKEN_EOF)) {
        if (parser->had_error) {
            break;
        }

        RavaModifier_e *modifiers = NULL;
        size_t modifiers_count = 0;
        _rava_parser_parse_modifiers(parser, &modifiers, &modifiers_count);

        RavaASTNode_t *decl = NULL;

        if (_rava_parser_check(parser, RAVA_TOKEN_KEYWORD_INTERFACE)) {
            RavaToken_t *saved = parser->current_token;
            parser->current_token = saved;
            free(modifiers);
            decl = _rava_parser_parse_interface_declaration(parser);
        } else if (_rava_parser_check(parser, RAVA_TOKEN_KEYWORD_CLASS)) {
            RavaToken_t *saved = parser->current_token;
            parser->current_token = saved;
            free(modifiers);
            decl = _rava_parser_parse_class_declaration(parser);
        } else {
            free(modifiers);
            break;
        }

        if (decl) {
            rava_ast_node_add_child(root, decl);
        }
    }

    return root;
}