<?php

namespace App\Services;

use Illuminate\Support\Collection;
use Illuminate\Support\Facades\File;

class CodeContextService
{
    private int $contextLines = 10;

    public function __construct(
        private readonly ConfigService $configService,
        private readonly EnvService $envService
    ) {}

    /**
     * 根据 app_name 获取代码仓库路径
     *
     * @param string $appName
     * @return string|null
     */
    public function getRepoPath(string $appName): ?string
    {
        $appEnvMap = $this->configService->get('log_analysis.app_env_map', []);

        if (!isset($appEnvMap[$appName])) {
            return null;
        }

        $mapping = $appEnvMap[$appName];
        $project = $mapping['project'] ?? null;
        $env = $mapping['env'] ?? null;

        if (!$project || !$env) {
            return null;
        }

        try {
            $envContent = $this->envService->getEnvContent($project, $env);
            $repoPath = $this->parseEnvValue($envContent, 'LOG_ANALYSIS_CODE_REPO_PATH');

            if ($repoPath && is_dir($repoPath)) {
                return $repoPath;
            }
        } catch (\Exception $e) {
            // 忽略错误，返回 null
        }

        return null;
    }

    /**
     * 从日志中提取相关代码片段
     *
     * @param string $repoPath 代码仓库路径
     * @param Collection $logs 日志集合
     * @return string|null 代码上下文
     */
    public function extractRelevantCode(string $repoPath, Collection $logs): ?string
    {
        $codeSnippets = [];
        $processedFiles = [];

        foreach ($logs as $log) {
            $file = $log['file'] ?? null;
            $line = $log['line'] ?? null;

            if (!$file || !$line) {
                // 尝试从 trace 中提取
                $extracted = $this->extractFileLineFromTrace($log['trace'] ?? '');
                if ($extracted) {
                    $file = $extracted['file'];
                    $line = $extracted['line'];
                }
            }

            if (!$file || !$line) {
                continue;
            }

            // 构建完整路径
            $fullPath = $this->resolveFilePath($repoPath, $file);
            if (!$fullPath || !File::exists($fullPath)) {
                continue;
            }

            // 避免重复处理同一文件的同一位置
            $key = "{$fullPath}:{$line}";
            if (isset($processedFiles[$key])) {
                continue;
            }
            $processedFiles[$key] = true;

            // 提取代码片段
            $snippet = $this->extractCodeSnippet($fullPath, (int) $line);
            if ($snippet) {
                $codeSnippets[] = $snippet;
            }

            // 限制代码片段数量
            if (count($codeSnippets) >= 5) {
                break;
            }
        }

        if (empty($codeSnippets)) {
            return null;
        }

        return implode("\n\n---\n\n", $codeSnippets);
    }

    /**
     * 提取指定文件指定行附近的代码
     *
     * @param string $filePath 文件路径
     * @param int $line 行号
     * @return string|null
     */
    public function extractCodeSnippet(string $filePath, int $line): ?string
    {
        if (!File::exists($filePath)) {
            return null;
        }

        $content = File::get($filePath);
        $lines = explode("\n", $content);
        $totalLines = count($lines);

        $startLine = max(1, $line - $this->contextLines);
        $endLine = min($totalLines, $line + $this->contextLines);

        $snippet = [];
        $snippet[] = "// File: " . basename($filePath);
        $snippet[] = "// Lines: {$startLine}-{$endLine} (target: {$line})";
        $snippet[] = "";

        for ($i = $startLine - 1; $i < $endLine; $i++) {
            $lineNum = $i + 1;
            $marker = ($lineNum === $line) ? '>>>' : '   ';
            $snippet[] = sprintf("%s %4d | %s", $marker, $lineNum, $lines[$i] ?? '');
        }

        return implode("\n", $snippet);
    }

    /**
     * 从堆栈跟踪中提取文件和行号
     *
     * @param string $trace
     * @return array|null ['file' => string, 'line' => int]
     */
    private function extractFileLineFromTrace(string $trace): ?array
    {
        // 匹配常见的堆栈跟踪格式
        // PHP: at /path/to/file.php:123
        // PHP: #0 /path/to/file.php(123): function()
        // Java: at com.example.Class.method(File.java:123)

        $patterns = [
            '/at\s+([^\s:]+):(\d+)/',
            '/#\d+\s+([^\s(]+)\((\d+)\)/',
            '/([^\s:]+\.php):(\d+)/',
            '/\(([^:]+):(\d+)\)/',
        ];

        foreach ($patterns as $pattern) {
            if (preg_match($pattern, $trace, $matches)) {
                return [
                    'file' => $matches[1],
                    'line' => (int) $matches[2],
                ];
            }
        }

        return null;
    }

    /**
     * 解析文件路径
     *
     * @param string $repoPath 仓库根路径
     * @param string $file 文件路径（可能是相对路径或绝对路径）
     * @return string|null
     */
    private function resolveFilePath(string $repoPath, string $file): ?string
    {
        // 如果是绝对路径且存在
        if (str_starts_with($file, '/') && File::exists($file)) {
            return $file;
        }

        // 尝试作为相对路径
        $fullPath = rtrim($repoPath, '/') . '/' . ltrim($file, '/');
        if (File::exists($fullPath)) {
            return $fullPath;
        }

        // 尝试在仓库中搜索文件名
        $filename = basename($file);
        $found = $this->findFileInRepo($repoPath, $filename);

        return $found;
    }

    /**
     * 在仓库中搜索文件
     *
     * @param string $repoPath
     * @param string $filename
     * @return string|null
     */
    private function findFileInRepo(string $repoPath, string $filename): ?string
    {
        $iterator = new \RecursiveIteratorIterator(
            new \RecursiveDirectoryIterator($repoPath, \RecursiveDirectoryIterator::SKIP_DOTS),
            \RecursiveIteratorIterator::SELF_FIRST
        );

        foreach ($iterator as $file) {
            if ($file->isFile() && $file->getFilename() === $filename) {
                return $file->getPathname();
            }
        }

        return null;
    }

    /**
     * 从 .env 内容中解析指定键的值
     *
     * @param string $envContent
     * @param string $key
     * @return string|null
     */
    private function parseEnvValue(string $envContent, string $key): ?string
    {
        $lines = explode("\n", $envContent);

        foreach ($lines as $line) {
            $line = trim($line);

            // 跳过注释和空行
            if (empty($line) || str_starts_with($line, '#')) {
                continue;
            }

            if (str_starts_with($line, "{$key}=")) {
                $value = substr($line, strlen($key) + 1);
                // 移除引号
                $value = trim($value, '"\'');
                return $value ?: null;
            }
        }

        return null;
    }

    /**
     * 设置上下文行数
     */
    public function setContextLines(int $lines): void
    {
        $this->contextLines = $lines;
    }
}