import { watch, readFileSync } from 'fs';
import { readdir, readFile, stat } from 'fs/promises';
import { resolve, basename, extname, join, dirname } from 'path';
import { fileURLToPath } from 'url';

// --- Configuration ---

const __dirname = dirname(fileURLToPath(import.meta.url));

function loadEnv() {
    const envPath = resolve(__dirname, '.env');
    try {
        const envFileContent = readFileSync(envPath, 'utf-8');
        envFileContent.split(/\r?\n/).forEach(line => {
            const trimmedLine = line.trim();
            if (trimmedLine && !trimmedLine.startsWith('#')) {
                const parts = trimmedLine.split('=', 2);
                if (parts.length === 2) {
                    const [key, value] = parts;
                    process.env[key.trim()] = value.trim().replace(/^"|"$/g, '');
                }
            }
        });
        console.log('Successfully loaded configuration from .env file.');
    } catch (error) {
        console.error('FATAL: Could not find or read the .env file. Please ensure it exists in the same directory as this script.');
        process.exit(1);
    }
}

loadEnv();

const { WEBHOOK_BASE_URL, BASIC_AUTH_USERNAME, BASIC_AUTH_PASSWORD } = process.env;

if (!WEBHOOK_BASE_URL || !BASIC_AUTH_USERNAME || !BASIC_AUTH_PASSWORD) {
    console.error('FATAL: Please define WEBHOOK_BASE_URL, BASIC_AUTH_USERNAME, and BASIC_AUTH_PASSWORD in your .env file.');
    process.exit(1);
}

const WATCH_PATH = resolve(__dirname, '..', '..', '..', 'script-output', 'signal_export');
const DEBOUNCE_DELAY_MS = 250;
const debounceTimers = new Map<string, NodeJS.Timeout>();

// --- Core Logic ---

async function sendToWebhook(filePath: string) {
    try {
        const combinatorName = basename(filePath, extname(filePath));
        const url = `${WEBHOOK_BASE_URL}/${encodeURIComponent(combinatorName)}`;
        const content = await readFile(filePath, 'utf-8');
        
        // Silently ignore empty files, which can occur during file writing.
        if (!content.trim()) return;
        JSON.parse(content);

        const authHeader = 'Basic ' + Buffer.from(`${BASIC_AUTH_USERNAME}:${BASIC_AUTH_PASSWORD}`).toString('base64');
        
        console.log(`Sending data for '${combinatorName}'...`);

        const response = await fetch(url, {
            method: 'POST', // Using POST to send a request body, as is standard for webhooks.
            headers: {
                'Content-Type': 'application/json',
                'Authorization': authHeader,
            },
            body: content,
        });

        if (!response.ok) {
            throw new Error(`HTTP Error: ${response.status} ${response.statusText}`);
        }

        console.log(`Successfully sent data for '${combinatorName}'. Server responded with ${response.status}.`);
    } catch (err: any) {
        const fileName = basename(filePath);
        if (err instanceof SyntaxError) {
             console.error(`Skipping ${fileName}: Invalid JSON content. The file might be incomplete.`);
        } else {
             console.error(`Error sending webhook for ${fileName}:`, err.message);
        }
    }
}

function handleFileChange(filename: string | null) {
    if (!filename || !filename.endsWith('.json')) return;

    if (debounceTimers.has(filename)) {
        clearTimeout(debounceTimers.get(filename)!);
    }

    const newTimer = setTimeout(async () => {
        const fullPath = join(WATCH_PATH, filename);
        try {
            const stats = await stat(fullPath);
            if (stats.isFile()) {
                await sendToWebhook(fullPath);
            }
        } catch {
            // Error (e.g., file deleted before processing), ignore.
        } finally {
            debounceTimers.delete(filename);
        }
    }, DEBOUNCE_DELAY_MS);

    debounceTimers.set(filename, newTimer);
}

async function initialScanAndProcess() {
    console.log(`Performing initial scan of directory: ${WATCH_PATH}`);
    try {
        const files = await readdir(WATCH_PATH);
        const jsonFiles = files.filter(f => f.endsWith('.json'));
        console.log(`Found ${jsonFiles.length} existing JSON file(s). Processing...`);
        for (const file of jsonFiles) {
            await sendToWebhook(join(WATCH_PATH, file));
        }
    } catch (err: any) {
        console.error(`Error during initial scan: ${err.message}. Ensure the directory exists.`);
    }
}

// --- Script Execution ---

(async () => {
    await initialScanAndProcess();
    
    console.log(`\nWatching for file changes in: ${WATCH_PATH}`);
    try {
        watch(WATCH_PATH, (eventType, filename) => {
            if (filename) {
                console.log(`[${new Date().toLocaleTimeString()}] Event '${eventType}' on '${filename}'`);
                handleFileChange(filename);
            }
        });
        console.log("Watcher is now running. Press Ctrl+C to stop.");
    } catch (err: any) {
         console.error(`FATAL: Failed to start watcher. Please check if the path is correct. Error: ${err.message}`);
         process.exit(1);
    }
})();