const fs = require("fs");
const path = require("path");

const metadata = require("../tool_info.json");

function defaults() {
  return Object.fromEntries(
    Object.entries(metadata.settings_schema).map(([key, field]) => [key, structuredClone(field.default)])
  );
}

function readSettings(dataDir) {
  const fallback = defaults();
  try {
    const stored = JSON.parse(fs.readFileSync(settingsPath(dataDir), "utf8"));
    return normalizeSettings({ ...fallback, ...stored });
  } catch {
    return normalizeSettings(fallback);
  }
}

function writeSettings(dataDir, value) {
  const normalized = normalizeSettings({ ...defaults(), ...value });
  fs.mkdirSync(dataDir, { recursive: true });
  const file = settingsPath(dataDir);
  const temporary = `${file}.${process.pid}.tmp`;
  fs.writeFileSync(temporary, `${JSON.stringify(normalized, null, 2)}\n`, { mode: 0o600 });
  try { fs.chmodSync(temporary, 0o600); } catch {}
  fs.renameSync(temporary, file);
  return normalized;
}

function normalizeSettings(value) {
  const mode = value.policy_mode === "blacklist" ? "blacklist" : "whitelist";
  const adapter = value.provider_adapter === "generic_json" ? "generic_json" : "searxng_json";
  const safeSearch = ["off", "moderate", "strict"].includes(value.safe_search) ? value.safe_search : "strict";
  return {
    enabled: value.enabled === true,
    policy_mode: mode,
    url_rules: stringList(value.url_rules, 200),
    max_results: integer(value.max_results, 1, 10, 5),
    search_timeout_ms: integer(value.search_timeout_ms, 1000, 30000, 8000),
    cache_ttl_seconds: integer(value.cache_ttl_seconds, 0, 3600, 300),
    safe_search: safeSearch,
    allowed_origins: stringList(value.allowed_origins, 6)
      .filter((origin) => ["webui", "discord", "twitch", "youtube", "kick", "other"].includes(origin)),
    webui_output_chars: integer(value.webui_output_chars, 300, 12000, 4000),
    discord_output_chars: integer(value.discord_output_chars, 200, 4000, 1200),
    twitch_output_chars: integer(value.twitch_output_chars, 120, 1000, 350),
    youtube_output_chars: integer(value.youtube_output_chars, 120, 1500, 500),
    kick_output_chars: integer(value.kick_output_chars, 120, 1000, 350),
    other_output_chars: integer(value.other_output_chars, 120, 2000, 500),
    provider_adapter: adapter,
    provider_endpoint: String(value.provider_endpoint || "").trim(),
    provider_api_key: String(value.provider_api_key || "").trim(),
    provider_api_key_header: value.provider_api_key_header === "Authorization" ? "Authorization" : "X-API-Key",
    provider_api_key_prefix: String(value.provider_api_key_prefix || "").trim().slice(0, 32),
    provider_query_parameter: /^[A-Za-z][A-Za-z0-9_.-]{0,63}$/.test(String(value.provider_query_parameter || ""))
      ? String(value.provider_query_parameter)
      : "q",
    show_source_links: value.show_source_links !== false,
    allow_full_page_fetch: value.allow_full_page_fetch === true,
    requests_per_minute: integer(value.requests_per_minute, 1, 60, 6)
  };
}

function settingsPath(dataDir) {
  return path.join(dataDir, "settings.json");
}

function integer(value, minimum, maximum, fallback) {
  const number = Number.parseInt(value, 10);
  return Number.isFinite(number) ? Math.max(minimum, Math.min(maximum, number)) : fallback;
}

function stringList(value, limit) {
  const rows = Array.isArray(value) ? value : String(value || "").split(/\r?\n|,/);
  return [...new Set(rows.map((entry) => String(entry).trim()).filter(Boolean))].slice(0, limit);
}

module.exports = {
  defaults,
  normalizeSettings,
  readSettings,
  settingsPath,
  writeSettings
};