<?php

final class LegacyFunctionsTest extends PHPUnit\Framework\TestCase
{
    public function testOnlySelectedTopLevelFunctionIsExtracted(): void
    {
        $source = <<<'SOURCE'
<?php
file_put_contents('/never-execute', 'startup');
// function wanted() { wrong }
class Example { function wanted() { return 'method'; } }
function unwanted() { return '}'; }
function wanted($name) { /* } */ return "{$name}: }"; }
SOURCE;
        $found = LegacyFunctions::extract($source, ['wanted']);
        self::assertSame(['wanted'], array_keys($found));
        self::assertSame('function wanted($name) { /* } */ return "{$name}: }"; }', $found['wanted']['code']);
        self::assertSame(6, $found['wanted']['line']);
    }

    public function testMissingFunctionFailsClosed(): void
    {
        $this->expectException(RuntimeException::class);
        LegacyFunctions::extract('<?php function different() {}', ['wanted']);
    }

    public function testNestedFunctionCannotBeMistakenForGlobalDeclaration(): void
    {
        $this->expectException(RuntimeException::class);
        LegacyFunctions::extract('<?php function outer() { function wanted() {} }', ['wanted']);
    }

    public function testIncludesCannotLoadApplicationBootstrap(): void
    {
        $this->expectException(RuntimeException::class);
        LegacyFunctions::extract('<?php function wanted() { require "db.php"; }', ['wanted']);
    }

    public function testDuplicateDefinitionsFailClosed(): void
    {
        $this->expectException(RuntimeException::class);
        LegacyFunctions::extract('<?php function wanted() {} function wanted() {}', ['wanted']);
    }
}