import { readFileSync, readdirSync } from 'node:fs';
import { resolve, dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';
import { createHash, randomUUID } from 'node:crypto';
import { getDb } from '../db/index.js';

const __dirname = dirname(fileURLToPath(import.meta.url));
const SEED_DIR = resolve(__dirname, '../../data/seed');

// Deterministic UUID v5-style derived from slug; stable across DB rebuilds.
function uuidFromSlug(slug) {
    const h = createHash('sha1').update('oradio:' + slug).digest('hex');
    return [
        h.slice(0, 8),
        h.slice(8, 12),
        '5' + h.slice(13, 16),
        '8' + h.slice(17, 20),
        h.slice(20, 32)
    ].join('-');
}

function loadAllSeedFiles() {
    const files = readdirSync(SEED_DIR)
        .filter((f) => f.startsWith('stations') && f.endsWith('.json'))
        .sort();
    const all = [];
    for (const f of files) {
        try {
            const data = JSON.parse(readFileSync(join(SEED_DIR, f), 'utf8'));
            if (Array.isArray(data)) all.push(...data);
        } catch (err) {
            console.warn(`[seed] failed to load ${f}:`, err.message);
        }
    }
    return all;
}

export function loadSeedFile() {
    return loadAllSeedFiles();
}

export function loadCategoriesFile() {
    try {
        const txt = readFileSync(join(SEED_DIR, 'categories.json'), 'utf8');
        return JSON.parse(txt);
    } catch {
        return [];
    }
}

/**
 * Merge-by-UUID seeder. Inserts stations and streams whose UUIDs are not yet in
 * the database. Existing stations are left untouched (admin edits are preserved).
 */
export function applySeed() {
    const db = getDb();

    const stationByUuid = db.prepare('SELECT id FROM stations WHERE uuid = ?');
    const streamByUuid = db.prepare('SELECT id FROM streams WHERE uuid = ?');

    const insertStation = db.prepare(`
    INSERT INTO stations (uuid, name, slug, homepage, country, genres, description, image_url, category, source, source_ref)
    VALUES (@uuid, @name, @slug, @homepage, @country, @genres, @description, @image_url, @category, 'seed', @slug)
  `);
    const insertStream = db.prepare(`
    INSERT INTO streams (uuid, station_id, url, format, bitrate, label, priority)
    VALUES (@uuid, @station_id, @url, @format, @bitrate, @label, @priority)
  `);

    const entries = loadAllSeedFiles();
    let inserted = 0;
    let streamsInserted = 0;
    let skipped = 0;

    const tx = db.transaction((list) => {
        for (const s of list) {
            const uuid = s.uuid || uuidFromSlug(s.slug);
            const existing = stationByUuid.get(uuid);
            if (existing) {
                skipped++;
                continue;
            }
            const info = insertStation.run({
                uuid,
                name: s.name,
                slug: s.slug,
                homepage: s.homepage ?? null,
                country: s.country ?? null,
                genres: JSON.stringify(s.genres ?? []),
                description: s.description ?? null,
                image_url: s.image_url ?? null,
                category: s.category ?? null
            });
            const stationId = info.lastInsertRowid;
            let priority = 0;
            for (const st of s.streams ?? []) {
                const streamUuid = st.uuid || randomUUID();
                if (streamByUuid.get(streamUuid)) continue;
                insertStream.run({
                    uuid: streamUuid,
                    station_id: stationId,
                    url: st.url,
                    format: st.format ?? 'unknown',
                    bitrate: st.bitrate ?? null,
                    label: st.label ?? null,
                    priority: st.priority ?? priority
                });
                streamsInserted++;
                priority++;
            }
            inserted++;
        }
    });
    tx(entries);

    return { inserted, streamsInserted, skipped, total: entries.length };
}

// Back-compat shim: bootstrap and reseed call applySeedIfEmpty(); now always merges.
export function applySeedIfEmpty() {
    return applySeed();
}