import fs from 'fs';
import path from 'path';
import { Database } from 'bun:sqlite';
import dotenv from 'dotenv';

dotenv.config({ path: '../.env' });
const jsonFolder = path.resolve(process.env.STREAM_JSON_LOCATION);
const dbName = 'strimserve.db';
const db = new Database(dbName);

// Map JSON attribute names to database column names
// Not needed today, but makes schema changes easier
const lookup = {
    id: 'id',
    date: 'stream_date',
    filename: 'filename',
    format: 'format',
    title: 'title',
    tags: 'tags',
    description: 'description',
    length_seconds: 'length_seconds',
    tracks: 'tracks'
};

const existingRow = db.prepare('SELECT * FROM Stream WHERE id = ?');

// Overwrite differing streams without asking
const shouldOverwrite = process.argv.includes('--overwrite');

// Process JSON files and insert data into Stream
const files = fs.readdirSync(jsonFolder);
console.log(`Found ${files.length} JSON file(s) in ${jsonFolder}.`);

for (const file of files) {
    if (!file.endsWith('.json')) continue;
    if (file.endsWith('.sideload.json')) continue;

    const jsonString = fs.readFileSync(path.join(jsonFolder, file), 'utf8');
    let jsonData = JSON.parse(jsonString);

    const sideloadPath = path.join(jsonFolder, file.slice(0, -5) + '.sideload.json');
    if (fs.existsSync(sideloadPath)) {
        const sideloadData = JSON.parse(fs.readFileSync(sideloadPath));
        jsonData = { ...jsonData, ...sideloadData };
    }

    // A key with no column would otherwise reach the query as `undefined`
    const unknown = Object.keys(jsonData).filter((key) => !(key in lookup));
    if (unknown.length > 0)
        console.log(`Ignored unknown key(s) in ${file}: ${unknown.join(', ')}.`);

    // Prepare attributes for insertion
    const fields = Object.entries(jsonData)
        .filter(([key]) => key in lookup)
        // Serialize value if array
        .map(([key, value]) => [lookup[key], Array.isArray(value) ? JSON.stringify(value) : value]);

    const row = existingRow.get(jsonData.id);
    if (row) {
        const changed = fields
            .filter(([column, value]) => String(row[column] ?? '') !== String(value ?? ''))
            .map(([column]) => column);

        if (changed.length === 0) {
            console.log(`Unchanged data for ID ${jsonData.id}.`);
            continue;
        }

        console.log(`ID ${jsonData.id} differs from the database in: ${changed.join(', ')}.`);
        if (!shouldOverwrite && !confirm(`Overwrite ID ${jsonData.id}?`)) {
            console.log(`Kept database version of ID ${jsonData.id}.`);
            continue;
        }
    }

    const columns = fields.map(([column]) => column);
    const sql = `INSERT OR REPLACE INTO Stream (${columns.join(', ')}) VALUES (${columns.map(() => '?').join(', ')})`;
    db.prepare(sql).run(...fields.map(([, value]) => value));
    console.log(`Inserted data for ID ${jsonData.id}.`);
}