import path from "node:path";
import { config as dotenvConfig } from "dotenv";

// Chargement du .env : d'abord le .env du paquet serveur, puis celui de la racine du repo.
// Les variables déjà présentes dans l'environnement ne sont jamais écrasées.
dotenvConfig({ path: [".env", "../.env"] });

export interface Config {
  port: number;
  host: string;
  dataDir: string;
  sessionTtlMs: number;
  sessionAbsoluteTtlMs: number;
  maxLoginAttemptsPerMinute: number;
  cookieSecure: boolean;
  trustProxy: boolean;
  publicDir: string | null;
  external: {
    adapter: "example" | "http";
    baseUrl: string;
    apiKey: string;
    healthPath: string;
    listPath: string;
    timeoutMs: number;
    retries: number;
    cacheTtlMs: number;
  };
}

function envStr(name: string, fallback: string): string {
  const value = process.env[name];
  return value === undefined || value === "" ? fallback : value;
}

function envInt(name: string, fallback: number): number {
  const raw = process.env[name];
  if (raw === undefined || raw === "") return fallback;
  const value = Number.parseInt(raw, 10);
  if (Number.isNaN(value) || value <= 0) {
    throw new Error(`Variable d'environnement ${name} invalide : ${raw} (entier positif attendu)`);
  }
  return value;
}

function envBool(name: string, fallback: boolean): boolean {
  const raw = process.env[name];
  if (raw === undefined || raw === "") return fallback;
  return raw === "1" || raw.toLowerCase() === "true";
}

export function loadConfig(): Config {
  const dataDir = path.resolve(process.cwd(), envStr("SEICHE_DATA_DIR", "./data"));
  return {
    port: envInt("SEICHE_PORT", 8787),
    host: envStr("SEICHE_HOST", "127.0.0.1"),
    dataDir,
    sessionTtlMs: envInt("SEICHE_SESSION_TTL_MS", 8 * 60 * 60 * 1000),
    sessionAbsoluteTtlMs: envInt("SEICHE_SESSION_ABSOLUTE_TTL_MS", 7 * 24 * 60 * 60 * 1000),
    maxLoginAttemptsPerMinute: envInt("SEICHE_MAX_LOGIN_ATTEMPTS_PER_MINUTE", 5),
    cookieSecure: envBool("SEICHE_COOKIE_SECURE", false),
    trustProxy: envBool("SEICHE_TRUST_PROXY", false),
    publicDir: process.env.SEICHE_PUBLIC_DIR ?? null,
    external: {
      adapter: (process.env.SEICHE_EXTERNAL_ADAPTER ?? "example") as "example" | "http",
      baseUrl: envStr("SEICHE_EXTERNAL_BASE_URL", ""),
      apiKey: envStr("SEICHE_EXTERNAL_API_KEY", ""),
      healthPath: envStr("SEICHE_EXTERNAL_HEALTH_PATH", "/health"),
      listPath: envStr("SEICHE_EXTERNAL_LIST_PATH", "/items"),
      timeoutMs: envInt("SEICHE_EXTERNAL_TIMEOUT_MS", 10_000),
      retries: envInt("SEICHE_EXTERNAL_RETRIES", 2),
      cacheTtlMs: envInt("SEICHE_EXTERNAL_CACHE_TTL_MS", 30_000),
    },
  };
}