/*
 * Copyright (c) 2025 Quinn Stephens and the OSMORA team.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdarg.h>
#include <stdio.h>
#include "lexer.h"
#include "log.h"
#include "parser.h"
#include "parser/ast.h"
#include "parser/types.h"

static void
tok_error(struct token *tok, const char *fmt, ...)
{
    va_list args;

    fprintf(stderr, "\033[1;97m%d:%d: \033[1;91merror: \033[0m", tok->line, tok->col);
    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);
}

static bool
parse_func_decl(struct lexer *lexer, struct token *tok, struct ast_node *func)
{
    /*
     * TODO: Parse parameters.
     */
    lexer_next(lexer, tok);
    if (tok->kind != TOK_RPAREN) {
        tok_error(tok, "expected \")\" after \"(\"\n");
        free(func);
        return false;
    }

    /*
     * TODO: Parse body.
     */
    lexer_next(lexer, tok);
    if (tok->kind != TOK_SEMICOLON) {
        tok_error(tok, "expected \";\" after \")\"\n");
        free(func);
        return false;
    }

    /*
     * TODO: Keep track of nodes.
     */
    log_debug("Parsed function \"%.*s\" (return type %s)\n", func->name_len, func->name, func->type->name);
    free(func);

    lexer_next(lexer, tok);
    return true;
}

static bool
parse_decl(struct lexer *lexer, struct token *tok)
{
    struct type *type;
    struct ast_node *node;

    /*
     * TODO: Parse custom types.
     */
    if (!(tok->flags & TF_BUILTIN_TYPE)) {
        tok_error(tok, "expected type\n");
        return false;
    }

    type = types_find_builtin(tok->kind);
    if (type == NULL) {
        return false;
    }

    lexer_next(lexer, tok);
    if (tok->kind != TOK_IDENTIFIER) {
        tok_error(tok, "expected identifier after type\n");
        return false;
    }

    node = malloc(sizeof(struct ast_node));
    if (node == NULL) {
        log_error("failed to allocate memory for AST node\n");
        return false;
    }

    node->kind = NOK_UNKNOWN;
    node->name = tok->pos;
    node->name_len = tok->len;
    node->type = type;
    node->ptr_levels = 0;

    lexer_next(lexer, tok);
    if (tok->kind == TOK_LPAREN) {
        return parse_func_decl(lexer, tok, node);
    }

    /*
     * TODO: Parse variable declarations.
     */
    tok_error(tok, "expected \"(\" after identifier\n");
    free(node);
    return false;
}

bool
parser_parse(struct lexer *lexer)
{
    struct token tok;
    bool success;

    log_debug("parsing...\n");

    if (!lexer_next(lexer, &tok)) {
        log_error("failed to get first token\n");
        return false;
    }

    while (tok.kind != TOK_EOF) {
        if (tok.kind == TOK_UNKNOWN) {
            tok_error(&tok, "unrecognized token\n");
            return false;
        }

        if ((tok.flags & TF_BUILTIN_TYPE) || tok.kind == TOK_IDENTIFIER) {
            success = parse_decl(lexer, &tok);
        }

        if (!success) {
            return false;
        }
    }

    return true;
}