/*
* Copyright (C) 2023 Carlos Maniero
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
#define MUNIT_ENABLE_ASSERT_ALIASES
#include "ast.h"
#include "lexer.h"
#include "munit.h"
#include "parser.h"
#include "string.h"
#include "vector.h"

void assert_string_view_equal(char *expected, string_view_t actual);

void
make_lexer_from_static_src(lexer_t *lexer, char *src)
{
  lexer->filepath = "test.pipa";
  lexer->srclen   = 0;
  lexer->cur      = 0;
  lexer->row      = 0;
  lexer->bol      = 0;
  lexer->src      = src;
  lexer->srclen   = strlen(src);
}

void
assert_parser_error(char* src, char* error_msg) {
  parser_t parser;
  lexer_t lexer;

  make_lexer_from_static_src(&lexer, src);
  parser_init(&parser, &lexer);

  ast_node_t *ast_function = ast_node_new();

  bool parsed = parser_parse_function_declaration(&parser, ast_function);
  assert_false(parsed);
  assert_int(1, ==, parser.errors_len);
  assert_string_equal(error_msg, parser.errors[0].message);

  ast_node_destroy(ast_function);
}

static MunitResult
test_parse_function(const MunitParameter params[],
                    void *user_data_or_fixture)
{
  parser_t parser;
  lexer_t lexer;

  make_lexer_from_static_src(&lexer, "main(): i32 { \nreturn 42;\n }");
  parser_init(&parser, &lexer);
  ast_node_t *ast_function = ast_node_new();

  bool parsed = parser_parse_function_declaration(&parser, ast_function);
  assert_true(parsed);

  char actual[5];

  string_view_to_str(&ast_function->data.function.name, actual);
  assert_string_equal("main", actual);
  assert_int(AST_FUNCTION_DECLARATION, ==, ast_function->kind);

  ast_node_t *ast_return = vector_at(ast_function->data.function.body, 0);

  assert_int(AST_RETURN_STMT, ==, ast_return->kind);

  ast_node_t *ast_literal = ast_return->data.return_stmt.argument;

  assert_int(AST_LITERAL, ==, ast_literal->kind);
  assert_int(42, ==, ast_literal->data.literal.value.integer);

  ast_node_destroy(ast_function);

  return MUNIT_OK;
}

static MunitResult
test_parse_variable_definition(const MunitParameter params[],
                               void *user_data_or_fixture)
{
  parser_t parser;
  lexer_t lexer;

  make_lexer_from_static_src(&lexer, "main(): i32 { \nvariable : i32 = 42; \nreturn variable;\n }");
  parser_init(&parser, &lexer);
  ast_node_t *ast_function = ast_node_new();

  bool parsed = parser_parse_function_declaration(&parser, ast_function);

  assert_true(parsed);

  char actual[5];

  string_view_to_str(&ast_function->data.function.name, actual);
  assert_string_equal("main", actual);
  assert_int(AST_FUNCTION_DECLARATION, ==, ast_function->kind);

  ast_node_t *ast_variable = vector_at(ast_function->data.function.body, 0);

  assert_int(AST_VARIABLE_DECLARATION, ==, ast_variable->kind);
  assert_string_view_equal("variable", ast_variable->data.variable.name);

  ast_node_t *ast_return = vector_at(ast_function->data.function.body, 1);

  assert_int(AST_RETURN_STMT, ==, ast_return->kind);

  ast_node_t *ast_literal = ast_return->data.return_stmt.argument;

  assert_int(AST_IDENTIFIER, ==, ast_literal->kind);
  assert_string_view_equal("variable", ast_literal->data.identifier.name);

  ast_node_destroy(ast_function);

  return MUNIT_OK;
}

static MunitResult
test_parse_arithmetic_expression(const MunitParameter params[],
                                 void *user_data_or_fixture)
{
  parser_t parser;
  lexer_t lexer;

  make_lexer_from_static_src(&lexer, "1 + 3 * 3 / 2 - 1");
  parser_init(&parser, &lexer);

  ast_node_t *ast_expression = ast_node_new();
  bool parsed = parser_parse_expression(&parser, ast_expression);
  assert_true(parsed);

  ast_node_t *exp1 = ast_expression;
  {

    assert_int(AST_BINARY_OPERATION, ==, exp1->kind);
    assert_string_view_equal("-", exp1->data.binary_operation.op);

    ast_node_t *exp2 = exp1->data.binary_operation.left;
    {

      assert_int(AST_BINARY_OPERATION, ==, exp2->kind);
      assert_string_view_equal("+", exp2->data.binary_operation.op);

      assert_int(AST_LITERAL, ==, exp2->data.binary_operation.left->kind);
      assert_int(exp2->data.binary_operation.left->data.literal.value.integer, ==, 1);

      ast_node_t *exp3 = exp2->data.binary_operation.right;
      {

        assert_int(AST_BINARY_OPERATION, ==, exp3->kind);
        assert_string_view_equal("/", exp3->data.binary_operation.op);

        ast_node_t *exp4 = exp3->data.binary_operation.left;
        {
          assert_int(AST_BINARY_OPERATION, ==, exp4->kind);
          assert_string_view_equal("*", exp4->data.binary_operation.op);

          assert_int(AST_LITERAL, ==, exp4->data.binary_operation.left->kind);
          assert_int(exp4->data.binary_operation.left->data.literal.value.integer, ==, 3);

          assert_int(AST_LITERAL, ==, exp4->data.binary_operation.right->kind);
          assert_int(exp4->data.binary_operation.right->data.literal.value.integer, ==, 3);
        }

        assert_int(AST_LITERAL, ==, exp3->data.binary_operation.right->kind);
        assert_int(exp3->data.binary_operation.right->data.literal.value.integer, ==, 2);
      }
    }

    assert_int(AST_LITERAL, ==, exp1->data.binary_operation.right->kind);
    assert_int(exp1->data.binary_operation.right->data.literal.value.integer, ==, 1);
  }

  ast_node_destroy(ast_expression);

  return MUNIT_OK;
}

void assert_string_view_equal(char *expected, string_view_t actual)
{
  size_t expected_len = strlen(expected);
  assert_int(expected_len, ==, actual.size);
  assert_memory_equal(expected_len, expected, actual.str);
}

static MunitResult
test_parse_basic_syntax_errors(const MunitParameter params[],
                               void *user_data_or_fixture)
{
  assert_parser_error("(): i32 { return 42; }"      , "expected 'TOKEN_NAME' but got '('");
  assert_parser_error("main): i32 { return 42; }"   , "expected '(' but got ')'");
  assert_parser_error("main(: i32 { return 42; }"   , "expected ')' but got ':'");
  assert_parser_error("main() i32 { return 42; }"   , "expected ':' but got 'TOKEN_NAME'");
  assert_parser_error("main(): { return 42; }"      , "expected 'TOKEN_NAME' but got '{'");
  assert_parser_error("main(): i32 return 42; }"    , "expected '{' but got 'TOKEN_NAME'");
  assert_parser_error("main(): i32 { 42; }"         , "expected 'TOKEN_NAME' but got 'TOKEN_NUMBER'");
  assert_parser_error("main(): i32 { return; }"     , "unexpected '; (;)' token");
  assert_parser_error("main(): i32 { return 42;"    , "expected '}' but got end of file");
  assert_parser_error("main(): beff { return 42; }" , "type 'beff' is not defined");
  // FIXME: once function calls are implemented, this error should inform that
  // neither a variable or function call was found.
  assert_parser_error("main(): i32 { oxi 42; }"     , "expected ':' but got 'TOKEN_NUMBER'");

  return MUNIT_OK;
}

static MunitTest tests[] = {
  { "/test_parse_function", test_parse_function, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
  { "/test_parse_function", test_parse_function, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
  { "/test_parse_basic_syntax_errors", test_parse_basic_syntax_errors, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
  { "/test_parse_arithmetic_expression", test_parse_arithmetic_expression, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
  { "/test_parse_arithmetic_expression", test_parse_arithmetic_expression, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
  { "/test_parse_variable_definition", test_parse_variable_definition, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
  { NULL, NULL, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL }
};

static const MunitSuite suite = {
  "/parser", tests, NULL, 1, MUNIT_SUITE_OPTION_NONE
};

int
main(int argc, char *argv[])
{
  return munit_suite_main(&suite, NULL, argc, argv);
  return EXIT_SUCCESS;
}