// api/server.js
const express = require('express');
const cors = require('cors');
const fs = require('fs/promises');
const path = require('path');
const {
    detectMode,
    executeEzoCommand
} = require('./ezo-command-service');
const app = express();
const PORT = Number(process.env.PORT || 3000);
const HISTORY_FILES = {
    temperature: 'timestamp,temperature\n',
    ph: 'timestamp,ph\n',
    do: 'timestamp,do\n',
    ec: 'timestamp,ec\n'
};
const LOGS_DIRECTORY = process.env.LOGS_DIRECTORY
    ? path.resolve(process.env.LOGS_DIRECTORY)
    : path.join(__dirname, '..', 'logs');

app.use(cors());
app.use(express.json());
app.use('/frontend', express.static(path.join(__dirname, '..', 'frontend')));
app.use('/data', express.static(path.join(__dirname, '..', 'data'), {
    etag: false,
    maxAge: 0
}));
app.use('/logs', express.static(LOGS_DIRECTORY, {
    etag: false,
    maxAge: 0
}));
app.use('/config', express.static(path.join(__dirname, '..', 'config'), {
    etag: false,
    maxAge: 0
}));

app.get('/', (req, res) => {
    res.redirect('/frontend/index.html');
});

app.get('/api/system/ezo', (req, res) => {
    const mode = detectMode();
    res.json({
        mode: mode.mode,
        message: mode.message
    });
});

// Función auxiliar para simular latencia
const delay = (ms) => new Promise(resolve => setTimeout(resolve, ms));

// Endpoint principal para obtener datos de los sensores (MOCK)
app.get('/api/sensors/:type', async (req, res) => {
    const sensorType = req.params.type;
    console.log(`[GET] Petición recibida para sensor: ${sensorType}`);

    // Simulación de latencia I2C y procesamiento (400ms)
    await delay(400);

    const data = [];
    const now = new Date();

    // Generamos 60 registros simulados
    for (let i = 60; i >= 0; i--) {
        const timestamp = new Date(now.getTime() - i * 1000).toISOString();

        // Simulación de valores con ruido térmico/químico
        const mockValues = {
            rtd: (25.0 + (Math.random() * 0.1 - 0.05)).toFixed(2),
            ph: (7.2 + (Math.random() * 0.04 - 0.02)).toFixed(2),
            do: (8.5 + (Math.random() * 0.1 - 0.05)).toFixed(2),
            ec: (1050 + (Math.random() * 10 - 5)).toFixed(0)
        };

        if (sensorType === 'all') {
            data.push({
                Timestamp: timestamp,
                Temperatura_C: mockValues.rtd,
                pH: mockValues.ph,
                DO_mgL: mockValues.do,
                EC_uS: mockValues.ec
            });
        } else if (mockValues[sensorType]) {
            data.push({
                Timestamp: timestamp,
                Sensor: sensorType.toUpperCase(),
                Valor: mockValues[sensorType]
            });
        } else {
            return res.status(400).json({ error: "Sensor no válido" });
        }
    }

    res.json(data);
});

// Consola EZO: usa I2C real en Raspberry Pi y modo demo en otros equipos.
app.post('/api/sensors/:type/command', async (req, res) => {
    try {
        const result = await executeEzoCommand(
            req.params.type.toLowerCase(),
            req.body.command,
            { dangerousConfirmed: req.body.dangerousConfirmed === true }
        );
        res.json(result);
    } catch (error) {
        res.status(error.status || 500).json({
            success: false,
            error: error.message
        });
    }
});

// --- RUTAS DE GESTIÓN DE ALMACENAMIENTO ---

// Variable global para simular la configuración de escritura del demonio C++
let loggingRateSeconds = 1;

app.post('/api/config/logging', (req, res) => {
    const requestedRate = Number(req.body.rate);
    const allowedRates = new Set([1, 5, 10, 60]);

    if (!allowedRates.has(requestedRate)) {
        return res.status(400).json({ success: false, error: 'Frecuencia no válida' });
    }

    loggingRateSeconds = requestedRate;
    console.log(`[SIMULACIÓN] Frecuencia configurada a: 1 registro cada ${loggingRateSeconds}s`);
    res.json({
        success: true,
        simulated: true,
        rate: loggingRateSeconds,
        message: 'Configuración aplicada únicamente al backend simulado.'
    });
});

app.post('/api/history/clear', async (req, res) => {
    try {
        await Promise.all(
            Object.entries(HISTORY_FILES).map(([name, header]) =>
                fs.writeFile(path.join(LOGS_DIRECTORY, `${name}.csv`), header, 'utf8')
            )
        );

        console.log('[SISTEMA] Archivos CSV históricos truncados.');
        res.json({
            success: true,
            message: 'Archivos de registro truncados correctamente.'
        });
    } catch (error) {
        console.error('[ERROR] No se pudieron truncar los historiales:', error);
        res.status(500).json({
            success: false,
            error: 'No se pudieron borrar los archivos históricos.'
        });
    }
});

if (require.main === module) {
    app.listen(PORT, () => {
        console.log(`[MOCK SERVER] Backend Node.js corriendo en http://localhost:${PORT}`);
    });
}

module.exports = {
    app,
    HISTORY_FILES
};