import express from 'express';
import multer from 'multer';
import { spawn } from 'child_process';
import { writeFile, unlink, readFile } from 'fs/promises';
import { createReadStream } from 'fs';
import path from 'path';
import { v4 as uuidv4 } from 'uuid';
import fetch from 'node-fetch';
import { startCleanupJob } from './cleanup.js';

const TEMP_DIR = '/tmp';
const app = express();
const PORT = process.env.PORT || 7860;

export const tasks = {};

app.use(express.json());
app.use(express.urlencoded({ extended: true }));

const storage = multer.memoryStorage();
const upload = multer({ storage: storage });

const downloadFile = async (url) => {
    const response = await fetch(url);
    if (!response.ok) {
        throw new Error(`Failed to download file: ${response.statusText}`);
    }
    const arrayBuffer = await response.arrayBuffer();
    return Buffer.from(arrayBuffer);
};

// --- "УМНЫЙ" ЭНДПОИНТ ДЛЯ ПОТОКОВОЙ ОБРАБОТКИ ---
app.post('/api/run/stream', upload.single('file'), async (req, res) => {
    try {
        const { command, args: argsJson, file_url } = req.body;
        const file = req.file;

        if (!command) return res.status(400).json({ error: 'Parameter "command" is required.' });
        
        let args;
        try {
           args = argsJson ? JSON.parse(argsJson) : [];
        } catch(e) {
           return res.status(400).json({ error: 'Parameter "args" must be a valid JSON array.' });
        }

        let inputBuffer;
        if (file) {
            inputBuffer = file.buffer;
        } else if (file_url) {
            inputBuffer = await downloadFile(file_url);
        } else {
            return res.status(400).json({ error: 'A file must be provided via "file" or "file_url".' });
        }
        
        // --- СПЕЦИАЛЬНАЯ ЛОГИКА ДЛЯ FFMPEG ---
        if (command === 'ffmpeg') {
            const inputFilePath = path.join(TEMP_DIR, `${uuidv4()}-input`);
            const outputFilePath = path.join(TEMP_DIR, `${uuidv4()}-output`);
            
            try {
                await writeFile(inputFilePath, inputBuffer);

                const processedArgs = args.map(arg => 
                    arg.replace('{INPUT_FILE}', inputFilePath)
                       .replace('{OUTPUT_FILE}', outputFilePath)
                );

                const process = spawn(command, processedArgs);
                let stderrChunks = [];
                process.stderr.on('data', (data) => stderrChunks.push(data));

                process.on('close', async (code) => {
                    if (code === 0) {
                        try {
                            const outputBuffer = await readFile(outputFilePath);
                            res.setHeader('Content-Type', 'application/octet-stream');
                            res.send(outputBuffer);
                        } catch (readError) {
                            res.status(500).json({ error: "Command succeeded, but failed to read output file.", message: readError.message });
                        }
                    } else {
                        const stderr = Buffer.concat(stderrChunks).toString('utf8');
                        res.status(500).json({ error: 'Command execution failed.', code: code, stderr: stderr });
                    }
                    // Очистка
                    await unlink(inputFilePath).catch(()=>{});
                    await unlink(outputFilePath).catch(()=>{});
                });
            } catch (execError) {
                 res.status(500).json({ error: "Failed during ffmpeg file operations.", message: execError.message });
                 await unlink(inputFilePath).catch(()=>{});
                 await unlink(outputFilePath).catch(()=>{});
            }
        // --- ОБЫЧНАЯ ЛОГИКА ДЛЯ ДРУГИХ КОМАНД ---
        } else {
            const process = spawn(command, args);
            let stdoutChunks = [];
            let stderrChunks = [];
            
            process.stdout.on('data', (data) => stdoutChunks.push(data));
            process.stderr.on('data', (data) => stderrChunks.push(data));

            process.on('close', (code) => {
                if (code === 0) {
                    res.setHeader('Content-Type', 'application/octet-stream');
                    res.send(Buffer.concat(stdoutChunks));
                } else {
                    const stderr = Buffer.concat(stderrChunks).toString('utf8');
                    res.status(500).json({ error: 'Command execution failed.', code: code, stderr: stderr });
                }
            });

            process.stdin.write(inputBuffer);
            process.stdin.end();
        }

    } catch (error) {
        res.status(500).json({ error: 'Server error during stream processing.', message: error.message });
    }
});


// --- СИСТЕМА АСИНХРОННЫХ ЗАДАЧ (ОСТАЕТСЯ КАК АЛЬТЕРНАТИВА) ---
// ... (остальной код для /api/task/* и /api/download/* без изменений) ...

const executeTask = async (taskId) => {
    const task = tasks[taskId];
    const { command, args, inputBuffer, outputFilename } = task.payload;
    const tempFiles = [];

    try {
        tasks[taskId].status = 'processing';
        tasks[taskId].startTime = Date.now();
        const originalName = task.payload.originalName?.replace(/[^a-zA-Z0-9._-]/g, '') || 'input';
        const inputFilePath = path.join(TEMP_DIR, `${uuidv4()}-${originalName}`);
        const outputFilePath = path.join(TEMP_DIR, `${uuidv4()}-${outputFilename || 'output'}`);
        tempFiles.push(inputFilePath, outputFilePath);
        task.outputFilePath = outputFilePath;
        const processedArgs = args.map(arg => arg.replace('{INPUT_FILE}', inputFilePath).replace('{OUTPUT_FILE}', outputFilePath));
        await writeFile(inputFilePath, inputBuffer);
        const process = spawn(command, processedArgs);
        let stderrOutput = '';
        let totalDuration = 0;
        process.stderr.on('data', (data) => {
            const stderrLine = data.toString();
            stderrOutput += stderrLine;
            if (!totalDuration) {
                const durationMatch = stderrLine.match(/Duration: (\d{2}):(\d{2}):(\d{2})\.\d{2}/);
                if (durationMatch) {
                    totalDuration = parseInt(durationMatch[1]) * 3600 + parseInt(durationMatch[2]) * 60 + parseInt(durationMatch[3]);
                    task.estimatedTotalTime = totalDuration;
                }
            }
            const timeMatch = stderrLine.match(/time=(\d{2}):(\d{2}):(\d{2})\.\d{2}/);
            if (timeMatch && totalDuration) {
                const currentTime = parseInt(timeMatch[1]) * 3600 + parseInt(timeMatch[2]) * 60 + parseInt(timeMatch[3]);
                task.progress = Math.min(100, Math.round((currentTime / totalDuration) * 100));
            }
        });
        await new Promise((resolve, reject) => {
            process.on('close', (code) => {
                task.endTime = Date.now();
                task.stderr = stderrOutput;
                if (code === 0) {
                    task.status = 'completed';
                    task.result = { download_url: `/api/download/${path.basename(outputFilePath)}` };
                    resolve();
                } else {
                    const error = new Error(`Process exited with code ${code}`);
                    error.code = code;
                    reject(error);
                }
            });
            process.on('error', reject);
        });
    } catch (error) {
        tasks[taskId].status = 'failed';
        tasks[taskId].endTime = Date.now();
        tasks[taskId].error = { message: error.message, code: error.code };
        for (const filePath of tempFiles) { unlink(filePath).catch(() => {}); }
    }
};

app.get('/', (req, res) => { res.send('Task-based remote execution server is ready.'); });

app.post('/api/task/create', upload.single('file'), async (req, res) => {
    try {
        const { command, args: argsJson, file_url, output_filename } = req.body;
        const file = req.file;
        if (!command) return res.status(400).json({ error: 'Parameter "command" is required.' });
        let args;
        try { args = argsJson ? JSON.parse(argsJson) : []; } catch(e) { return res.status(400).json({ error: 'Parameter "args" must be a valid JSON array.' }); }
        let inputBuffer;
        if (file) { inputBuffer = file.buffer; } else if (file_url) { inputBuffer = await downloadFile(file_url); } else { return res.status(400).json({ error: 'A file must be provided via "file" or "file_url".' }); }
        const taskId = uuidv4();
        tasks[taskId] = { id: taskId, status: 'queued', progress: 0, submittedAt: Date.now(), payload: { command, args, outputFilename: output_filename, originalName: file?.originalname, inputBuffer, } };
        executeTask(taskId);
        res.status(202).json({ message: "Task accepted.", taskId: taskId, status_url: `/api/task/status/${taskId}` });
    } catch (error) {
        res.status(500).json({ error: 'Failed to create task.', message: error.message });
    }
});

app.get('/api/task/status/:taskId', (req, res) => {
    const { taskId } = req.params;
    const task = tasks[taskId];
    if (!task) { return res.status(404).json({ error: 'Task not found.' }); }
    const response = { id: task.id, status: task.status };
    if (task.startTime) {
        const endTime = task.endTime || Date.now();
        response.elapsedTimeSeconds = Math.round((endTime - task.startTime) / 1000);
    }
    if (task.status === 'processing') {
        response.progress = task.progress;
        if (task.estimatedTotalTime && response.elapsedTimeSeconds) {
            const remaining = task.estimatedTotalTime - response.elapsedTimeSeconds;
            response.estimatedTimeLeftSeconds = Math.max(0, remaining);
        }
    }
    if (task.status === 'completed') { response.result = task.result; }
    if (task.status === 'failed') { response.error = task.error; }
    res.status(200).json(response);
});

app.get('/api/download/:fileId', (req, res) => {
    const { fileId } = req.params;
    if (fileId.includes('..')) { return res.status(400).send('Invalid file ID.'); }
    const filePath = path.join(TEMP_DIR, fileId);
    const stream = createReadStream(filePath);
    stream.on('error', (err) => {
        if (err.code === 'ENOENT') { res.status(404).send('File not found or has been cleaned up.'); } else { res.status(500).send('Server error.'); }
    });
    res.setHeader('Content-Type', 'application/octet-stream');
    stream.pipe(res);
});

app.listen(PORT, () => { startCleanupJob(); });