/**
 * Translation aggregation script.
 *
 * Scans all `translations.json` files alongside components/widgets/views
 * in apps/web/src, merges them with the shared common messages, and writes
 * a combined per-locale message file to apps/web/messages/<locale>.json.
 *
 * Usage:
 *   pnpm i18n:aggregate
 *
 * During development, run this after adding new translation keys.
 * A watch-mode version should be wired into the dev workflow (future work).
 */

import { readFileSync, writeFileSync, readdirSync, statSync, existsSync } from 'fs';
import { join, dirname, relative } from 'path';
import { fileURLToPath } from 'url';

const __dirname = dirname(fileURLToPath(import.meta.url));
const repoRoot = join(__dirname, '..');
const webSrc = join(repoRoot, 'apps/web/src');
const messagesDir = join(repoRoot, 'apps/web/messages');
const locales = ['en'];

type TranslationTree = Record<string, unknown>;

/**
 * Recursively finds all `translations.json` files within a directory.
 */
function findTranslationFiles(dir: string): string[] {
    const results: string[] = [];
    for (const entry of readdirSync(dir)) {
        const full = join(dir, entry);
        const stat = statSync(full);
        if (stat.isDirectory()) {
            results.push(...findTranslationFiles(full));
        } else if (entry === 'translations.json') {
            results.push(full);
        }
    }
    return results;
}

/**
 * Deep-merges two translation trees. Conflicts are overwritten by `source`.
 */
function merge(target: TranslationTree, source: TranslationTree): TranslationTree {
    const result = { ...target };
    for (const [key, value] of Object.entries(source)) {
        if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
            result[key] = merge(
                (result[key] as TranslationTree | undefined) ?? {},
                value as TranslationTree,
            );
        } else {
            result[key] = value;
        }
    }
    return result;
}

for (const locale of locales) {
    const baseFile = join(messagesDir, `${locale}.json`);
    let base: TranslationTree = existsSync(baseFile)
        ? (JSON.parse(readFileSync(baseFile, 'utf-8')) as TranslationTree)
        : {};

    const translationFiles = findTranslationFiles(webSrc);
    for (const file of translationFiles) {
        const raw = JSON.parse(readFileSync(file, 'utf-8')) as TranslationTree;
        const localeData = (raw[locale] ?? raw) as TranslationTree;
        base = merge(base, localeData);

        const rel = relative(repoRoot, file);
        console.log(`  merged: ${rel}`);
    }

    writeFileSync(baseFile, JSON.stringify(base, null, 2) + '\n', 'utf-8');
    console.log(`✓ ${locale}: wrote ${baseFile}`);
}

console.log('Translation aggregation complete.');