/**
 * ─────────────────────────────────────────────
 *  SPB Git — Personal Git Platform
 * ─────────────────────────────────────────────
 *  Author  : Simon-Pierre Boucher
 *  Contact : contact@spboucher.ai
 *  File    : src/config.mjs
 *  Purpose : Environment loading + zod-validated configuration
 *  License : MIT © Simon-Pierre Boucher
 * ─────────────────────────────────────────────
 */

import { readFileSync, mkdirSync, existsSync } from 'node:fs';
import { resolve, join, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';
import process from 'node:process';
import { z } from 'zod';

export const PROJECT_ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '..');

/** The sole owner of this platform. Hard-coded on purpose — see CLAUDE.md §0. */
export const OWNER = Object.freeze({
  name: 'Simon-Pierre Boucher',
  email: 'contact@spboucher.ai',
  username: 'spb',
  site: 'https://spboucher.ai',
  tagline: 'Builder of models, clusters, and the tools that run them.',
});

const schema = z.object({
  SPBGIT_PORT: z.coerce.number().int().min(1).max(65535).default(7420),
  SPBGIT_HOST: z.string().min(1).default('127.0.0.1'),
  SPBGIT_PUBLIC_URL: z.string().url().default('https://git.spboucher.ai'),
  SPBGIT_GIT_ROOT: z.string().min(1).default('/srv/git'),
  SPBGIT_DATA_DIR: z.string().min(1).default('/srv/spbgit/data'),
  SPBGIT_CACHE_DIR: z.string().min(1).default('/srv/spbgit/cache'),
  SPBGIT_LOG_LEVEL: z.enum(['trace', 'debug', 'info', 'warn', 'error', 'fatal']).default('info'),
  SPBGIT_ENV: z.enum(['development', 'production', 'test']).default('production'),
});

/**
 * Parse a `.env`-style file into key/value pairs. Tiny on purpose — no dep.
 * @param {string} path
 * @returns {Record<string, string>}
 */
function parseEnvFile(path) {
  const out = {};
  let raw;
  try {
    raw = readFileSync(path, 'utf8');
  } catch {
    return out;
  }
  for (const line of raw.split('\n')) {
    const trimmed = line.trim();
    if (!trimmed || trimmed.startsWith('#')) continue;
    const eq = trimmed.indexOf('=');
    if (eq === -1) continue;
    const key = trimmed.slice(0, eq).trim();
    let value = trimmed.slice(eq + 1).trim();
    if ((value.startsWith('"') && value.endsWith('"')) || (value.startsWith("'") && value.endsWith("'"))) {
      value = value.slice(1, -1);
    }
    out[key] = value;
  }
  return out;
}

/**
 * Load, validate and freeze the runtime configuration.
 * Values in the real environment win over `.env` file values.
 * @param {Record<string, string|undefined>} [overrides] test-only overrides (highest precedence)
 * @returns {Readonly<object>} resolved config
 */
export function loadConfig(overrides = {}) {
  const fileEnv = parseEnvFile(join(PROJECT_ROOT, '.env'));
  const merged = { ...fileEnv, ...process.env, ...overrides };
  const parsed = schema.safeParse(merged);
  if (!parsed.success) {
    const issues = parsed.error.issues.map((i) => `  ${i.path.join('.')}: ${i.message}`).join('\n');
    throw new Error(`Invalid configuration:\n${issues}`);
  }
  const env = parsed.data;
  const abs = (p) => resolve(PROJECT_ROOT, p);
  const config = Object.freeze({
    env: env.SPBGIT_ENV,
    isDev: env.SPBGIT_ENV === 'development',
    port: env.SPBGIT_PORT,
    host: env.SPBGIT_HOST,
    publicUrl: env.SPBGIT_PUBLIC_URL.replace(/\/+$/, ''),
    logLevel: env.SPBGIT_LOG_LEVEL,
    gitRoot: abs(env.SPBGIT_GIT_ROOT),
    trashDir: join(abs(env.SPBGIT_GIT_ROOT), '.trash'),
    dataDir: abs(env.SPBGIT_DATA_DIR),
    cacheDir: abs(env.SPBGIT_CACHE_DIR),
    owner: OWNER,
  });
  return config;
}

/**
 * Create every directory the platform needs. Idempotent, fails loudly.
 * @param {ReturnType<typeof loadConfig>} config
 */
export function ensureDirs(config) {
  for (const dir of [config.gitRoot, config.trashDir, config.dataDir, config.cacheDir]) {
    if (!existsSync(dir)) {
      try {
        mkdirSync(dir, { recursive: true });
      } catch (err) {
        throw new Error(`Cannot create required directory ${dir}: ${err.message}`);
      }
    }
  }
}