/**
 * ─────────────────────────────────────────────
 *  SPB Git — Personal Git Platform
 * ─────────────────────────────────────────────
 *  Author  : Simon-Pierre Boucher
 *  Contact : contact@spboucher.ai
 *  File    : src/lib/store.mjs
 *  Purpose : meta.json repo index + activity feed (filesystem is the database)
 *  License : MIT © Simon-Pierre Boucher
 * ─────────────────────────────────────────────
 */

import { readFileSync, appendFileSync, existsSync, mkdirSync } from 'node:fs';
import { join } from 'node:path';
import { atomicWriteJSON } from './util.mjs';

const META_FILE = 'meta.json';
const ACTIVITY_FILE = 'activity.jsonl';
const ACTIVITY_MAX_READ = 500;

/**
 * Repo metadata store backed by `data/meta.json`.
 * Shape: { version: 1, repos: { [name]: { description, topics, homepage, pinned, created, defaultBranch } } }
 */
export class MetaStore {
  /** @param {string} dataDir */
  constructor(dataDir) {
    this.dataDir = dataDir;
    this.path = join(dataDir, META_FILE);
  }

  /** @returns {{version: number, repos: Record<string, object>}} */
  load() {
    if (!existsSync(this.path)) return { version: 1, repos: {} };
    try {
      const parsed = JSON.parse(readFileSync(this.path, 'utf8'));
      if (parsed && typeof parsed.repos === 'object') return parsed;
    } catch {
      /* corrupted meta falls back to empty — bare repos remain the truth */
    }
    return { version: 1, repos: {} };
  }

  /** @param {object} meta */
  save(meta) {
    atomicWriteJSON(this.path, meta);
  }

  /**
   * @param {string} name
   * @returns {object|null}
   */
  get(name) {
    return this.load().repos[name] ?? null;
  }

  /**
   * Create or merge a repo entry.
   * @param {string} name
   * @param {object} fields
   * @returns {object} the updated entry
   */
  upsert(name, fields = {}) {
    const meta = this.load();
    const existing = meta.repos[name] ?? {
      description: '',
      topics: [],
      homepage: '',
      pinned: false,
      created: new Date().toISOString(),
      defaultBranch: 'main',
    };
    meta.repos[name] = { ...existing, ...fields };
    this.save(meta);
    return meta.repos[name];
  }

  /** @param {string} name */
  remove(name) {
    const meta = this.load();
    delete meta.repos[name];
    this.save(meta);
  }
}

/**
 * Append-only push activity feed backed by `data/activity.jsonl`.
 */
export class ActivityFeed {
  /** @param {string} dataDir */
  constructor(dataDir) {
    this.path = join(dataDir, ACTIVITY_FILE);
    this.dataDir = dataDir;
  }

  /**
   * @param {{repo: string, ref: string, commits: number, sha: string}} event
   */
  append(event) {
    mkdirSync(this.dataDir, { recursive: true });
    const record = { ...event, at: new Date().toISOString() };
    appendFileSync(this.path, JSON.stringify(record) + '\n');
  }

  /**
   * @param {number} [limit]
   * @returns {object[]} newest-first events
   */
  recent(limit = 15) {
    if (!existsSync(this.path)) return [];
    const lines = readFileSync(this.path, 'utf8').trim().split('\n');
    const slice = lines.slice(-ACTIVITY_MAX_READ);
    const events = [];
    for (const line of slice) {
      try {
        events.push(JSON.parse(line));
      } catch {
        /* skip torn line */
      }
    }
    return events.reverse().slice(0, limit);
  }
}