<?php

namespace UbsCsvTransformer\Tests;

use PHPUnit\Framework\TestCase;
use UbsCsvTransformer\ConfigurationLoader;

class ConfigurationLoaderTest extends TestCase
{
    private string $tempFile = '';

    protected function setUp(): void
    {
        // uniqid gives a unique name; .json extension satisfies the loader's check
        $this->tempFile = sys_get_temp_dir() . '/cfgloader_test_' . uniqid() . '.json';
    }

    protected function tearDown(): void
    {
        if (file_exists($this->tempFile)) {
            unlink($this->tempFile);
        }
    }

    private function writeJson(array $data): void
    {
        file_put_contents($this->tempFile, json_encode($data));
    }

    /**
     * Minimal valid configuration that passes all validation checks.
     */
    private function validConfig(): array
    {
        return [
            'metadata' => [
                'extractionRules' => [
                    ['name' => 'account_iban', 'lineNumber' => 1, 'regex' => '(.+)'],
                ],
            ],
            'csvStructure' => [
                'headerLine' => 1,
                'inputDelimiter'  => ';',
                'encoding'   => 'UTF-8',
            ],
            'columnTransformations' => [
                ['sourceColumn' => 'A', 'outputColumn' => 'B', 'type' => 'map'],
            ],
        ];
    }

    // -------------------------------------------------------------------------
    // Happy path
    // -------------------------------------------------------------------------

    public function testLoadValidConfigReturnsArray(): void
    {
        $this->writeJson($this->validConfig());
        $loader = new ConfigurationLoader($this->tempFile);
        $config = $loader->load();
        $this->assertIsArray($config);
        $this->assertArrayHasKey('metadata', $config);
        $this->assertArrayHasKey('csvStructure', $config);
        $this->assertArrayHasKey('columnTransformations', $config);
    }

    public function testGetAllReturnsFullConfig(): void
    {
        $this->writeJson($this->validConfig());
        $loader = new ConfigurationLoader($this->tempFile);
        $loader->load();
        $all = $loader->getAll();
        $this->assertSame(1, $all['csvStructure']['headerLine']);
    }

    // -------------------------------------------------------------------------
    // get() dot-notation accessor
    // -------------------------------------------------------------------------

    public function testGetDotNotationReturnsValue(): void
    {
        $this->writeJson($this->validConfig());
        $loader = new ConfigurationLoader($this->tempFile);
        $loader->load();
        $this->assertSame(1, $loader->get('csvStructure.headerLine'));
        $this->assertSame(';', $loader->get('csvStructure.inputDelimiter'));
    }

    public function testGetNonExistentKeyReturnsNull(): void
    {
        $this->writeJson($this->validConfig());
        $loader = new ConfigurationLoader($this->tempFile);
        $loader->load();
        $this->assertNull($loader->get('nonexistent.key'));
    }

    public function testGetNonExistentKeyReturnsDefault(): void
    {
        $this->writeJson($this->validConfig());
        $loader = new ConfigurationLoader($this->tempFile);
        $loader->load();
        $this->assertSame('fallback', $loader->get('nonexistent', 'fallback'));
    }

    // -------------------------------------------------------------------------
    // File not found / bad extension
    // -------------------------------------------------------------------------

    public function testFileNotFoundThrows(): void
    {
        $this->expectException(\RuntimeException::class);
        $loader = new ConfigurationLoader('/nonexistent/path/config.json');
        $loader->load();
    }

    public function testNonJsonExtensionThrows(): void
    {
        $yamlPath = sys_get_temp_dir() . '/test_config_' . uniqid() . '.yaml';
        file_put_contents($yamlPath, 'key: value');
        try {
            $loader = new ConfigurationLoader($yamlPath);
            $this->expectException(\RuntimeException::class);
            $loader->load();
        } finally {
            if (file_exists($yamlPath)) {
                unlink($yamlPath);
            }
        }
    }

    public function testInvalidJsonThrows(): void
    {
        file_put_contents($this->tempFile, '{invalid json content}');
        $this->expectException(\RuntimeException::class);
        (new ConfigurationLoader($this->tempFile))->load();
    }

    // -------------------------------------------------------------------------
    // Required top-level sections
    // -------------------------------------------------------------------------

    public function testMissingMetadataSectionThrows(): void
    {
        $config = $this->validConfig();
        unset($config['metadata']);
        $this->writeJson($config);
        $this->expectException(\RuntimeException::class);
        (new ConfigurationLoader($this->tempFile))->load();
    }

    public function testMissingExtractionRulesThrows(): void
    {
        $config = $this->validConfig();
        unset($config['metadata']['extractionRules']);
        $this->writeJson($config);
        $this->expectException(\RuntimeException::class);
        (new ConfigurationLoader($this->tempFile))->load();
    }

    public function testMissingCsvStructureSectionThrows(): void
    {
        $config = $this->validConfig();
        unset($config['csvStructure']);
        $this->writeJson($config);
        $this->expectException(\RuntimeException::class);
        (new ConfigurationLoader($this->tempFile))->load();
    }

    public function testMissingHeaderLineThrows(): void
    {
        $config = $this->validConfig();
        unset($config['csvStructure']['headerLine']);
        $this->writeJson($config);
        $this->expectException(\RuntimeException::class);
        (new ConfigurationLoader($this->tempFile))->load();
    }

    public function testMissingColumnTransformationsThrows(): void
    {
        $config = $this->validConfig();
        unset($config['columnTransformations']);
        $this->writeJson($config);
        $this->expectException(\RuntimeException::class);
        (new ConfigurationLoader($this->tempFile))->load();
    }

    // -------------------------------------------------------------------------
    // csvStructure value validation
    // -------------------------------------------------------------------------

    public function testInvalidEncodingThrows(): void
    {
        $config = $this->validConfig();
        $config['csvStructure']['encoding'] = 'LATIN1';
        $this->writeJson($config);
        $this->expectException(\Exception::class);
        (new ConfigurationLoader($this->tempFile))->load();
    }

    public function testSupportedEncodingsPass(): void
    {
        foreach (['UTF-8', 'ISO-8859-1', 'CP1252'] as $encoding) {
            $config = $this->validConfig();
            $config['csvStructure']['encoding'] = $encoding;
            $this->writeJson($config);
            $loader = new ConfigurationLoader($this->tempFile);
            $result = $loader->load();
            $this->assertSame($encoding, $result['csvStructure']['encoding']);
        }
    }

    // -------------------------------------------------------------------------
    // directories validation
    // -------------------------------------------------------------------------

    public function testDirectoriesAllKeysPass(): void
    {
        $config = $this->validConfig();
        $config['directories'] = [
            'source'  => '/tmp/source',
            'output'  => '/tmp/output',
            'archive' => '/tmp/archive',
            'error'   => '/tmp/error',
        ];
        $this->writeJson($config);
        $result = (new ConfigurationLoader($this->tempFile))->load();
        $this->assertArrayHasKey('directories', $result);
    }

    public function testDirectoriesMissingSubkeyThrows(): void
    {
        $config = $this->validConfig();
        $config['directories'] = [
            'source' => '/tmp/source',
            'output' => '/tmp/output',
            // 'archive' and 'error' intentionally missing
        ];
        $this->writeJson($config);
        $this->expectException(\RuntimeException::class);
        (new ConfigurationLoader($this->tempFile))->load();
    }

    // -------------------------------------------------------------------------
    // Absent optional 'directories' key does not trigger validation
    // -------------------------------------------------------------------------

    public function testAbsentDirectoriesKeyDoesNotThrow(): void
    {
        $config = $this->validConfig();
        $this->assertArrayNotHasKey('directories', $config);
        $this->writeJson($config);
        $result = (new ConfigurationLoader($this->tempFile))->load();
        $this->assertArrayNotHasKey('directories', $result);
    }
}