/**
 * agent-helm daemon ("klienten") + hook-läge.
 *
 * Underkommandon:
 *   agent-helm connect [--server URL] [--name N] [--new] [--login]
 *       Loggar in mot servern via device-flödet första gången (skriver ut en
 *       URL att öppna + godkänna i webben), sparar ett klient-token lokalt, och
 *       kör sedan agenten i en pty och strömmar den över WS. Nästa start är tyst.
 *       --new  -> starta en ny parallell session istället för att återuppta.
 *       --login -> tvinga ny inloggning (t.ex. byt användare/server).
 *   agent-helm logout       -> radera sparat klient-token.
 *   agent-helm whoami       -> visa sparad inloggning.
 *   agent-helm hook         -> internt: anropas av agentens BeforeTool-hook.
 *
 * Klient-token + senaste session sparas i ~/.config/agent-helm/credentials.json.
 */
import { spawn, type IPty } from "@homebridge/node-pty-prebuilt-multiarch";
import { WebSocket } from "ws";
import http from "node:http";
import fs from "node:fs";
import path from "node:path";
import os from "node:os";
import { randomUUID } from "node:crypto";
import type { DaemonMessage, DeviceCodeResponse, DeviceTokenResponse } from "@agent-helm/shared";
import { parseMessage } from "@agent-helm/shared";

type Decision = { decision: "allow" | "deny"; reason?: string };

const HOOK_PORT = Number(process.env.AGENT_HELM_HOOK_PORT ?? 8788);
const AGENT_CMD = process.env.AGENT_CMD ?? "gemini";

/* ------------------------------ creds-hantering ---------------------------- */

interface Creds {
  server: string;
  token: string;
  clientName: string;
  user: string;
  lastSessionId?: string;
}

const CONFIG_DIR = process.env.AGENT_HELM_CONFIG_DIR || path.join(os.homedir(), ".config", "agent-helm");
const CRED_FILE = path.join(CONFIG_DIR, "credentials.json");

function loadCreds(): Creds | null {
  try {
    return JSON.parse(fs.readFileSync(CRED_FILE, "utf8")) as Creds;
  } catch {
    return null;
  }
}
function saveCreds(c: Creds): void {
  fs.mkdirSync(CONFIG_DIR, { recursive: true });
  fs.writeFileSync(CRED_FILE, JSON.stringify(c, null, 2), { mode: 0o600 });
}
function logout(): void {
  try {
    fs.unlinkSync(CRED_FILE);
    console.log("Utloggad — klient-token raderat.");
  } catch {
    console.log("Inget sparat token.");
  }
  process.exit(0);
}
function whoami(): void {
  const c = loadCreds();
  if (!c) {
    console.log("Ej inloggad.");
  } else {
    console.log(`Inloggad som ${c.user} mot ${c.server} (klient: ${c.clientName})`);
  }
  process.exit(0);
}

/* ------------------------------ CLI-argument ------------------------------- */

function flag(name: string): string | undefined {
  const i = process.argv.indexOf(name);
  return i >= 0 ? process.argv[i + 1] : undefined;
}
function has(name: string): boolean {
  return process.argv.includes(name);
}

function deriveUrls(input: string): { http: string; ws: string } {
  const u = input.replace(/\/$/, "");
  if (u.startsWith("ws://")) return { ws: u, http: "http://" + u.slice(5) };
  if (u.startsWith("wss://")) return { ws: u, http: "https://" + u.slice(6) };
  if (u.startsWith("http://")) return { http: u, ws: "ws://" + u.slice(7) };
  if (u.startsWith("https://")) return { http: u, ws: "wss://" + u.slice(8) };
  return { http: "https://" + u, ws: "wss://" + u }; // bara host angiven -> anta TLS
}

const sleep = (ms: number) => new Promise((r) => setTimeout(r, ms));

/* -------------------------------- device-flöde ----------------------------- */

async function deviceFlow(
  httpBase: string,
  clientName: string,
): Promise<{ token: string; sessionId: string; clientName: string; user: string }> {
  const codeRes = await fetch(`${httpBase}/api/device/code`, {
    method: "POST",
    headers: { "content-type": "application/json" },
    body: JSON.stringify({ clientName }),
  });
  if (!codeRes.ok) throw new Error(`device/code misslyckades (HTTP ${codeRes.status})`);
  const code = (await codeRes.json()) as DeviceCodeResponse;

  console.log("\n  ┌─────────────────────────────────────────────────────────────");
  console.log("  │  Öppna i webbläsaren, logga in och godkänn klienten:");
  console.log("  │");
  console.log(`  │    ${code.verificationUriComplete}`);
  console.log("  │");
  console.log(`  │  Kod: ${code.userCode}   (väntar på godkännande …)`);
  console.log("  └─────────────────────────────────────────────────────────────\n");

  const interval = Math.max(2, code.interval) * 1000;
  const deadline = Date.now() + code.expiresIn * 1000;
  while (Date.now() < deadline) {
    await sleep(interval);
    const tRes = await fetch(`${httpBase}/api/device/token`, {
      method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify({ deviceCode: code.deviceCode }),
    });
    const t = (await tRes.json()) as DeviceTokenResponse;
    if (t.status === "ready" && t.token && t.sessionId) {
      return { token: t.token, sessionId: t.sessionId, clientName: t.clientName ?? clientName, user: t.user ?? "?" };
    }
    if (t.status === "denied") throw new Error("godkännandet nekades i webben");
    if (t.status === "expired") throw new Error("koden gick ut innan godkännande");
    // pending / slow_down -> fortsätt polla
  }
  throw new Error("tidsgräns nådd utan godkännande");
}

/* --------------------------------- connect --------------------------------- */

async function runConnect(): Promise<void> {
  const input = flag("--server") || process.env.SERVER_URL || loadCreds()?.server;
  if (!input) {
    console.error("Ingen server angiven. Kör:  agent-helm connect --server https://din-helm-server");
    process.exit(1);
  }
  const { http: httpBase, ws: wsBase } = deriveUrls(input);
  const clientName = flag("--name") || process.env.AGENT_TITLE || `${AGENT_CMD} @ ${os.hostname()}`;

  let creds = loadCreds();
  const sameServer = creds && deriveUrls(creds.server).ws === wsBase;
  if (!creds || !sameServer || has("--login")) {
    console.log(`[daemon] loggar in mot ${httpBase} …`);
    try {
      const r = await deviceFlow(httpBase, clientName);
      creds = { server: input, token: r.token, clientName: r.clientName, user: r.user, lastSessionId: r.sessionId };
      saveCreds(creds);
      console.log(`[daemon] ✓ ansluten som ${r.user}.`);
    } catch (e) {
      console.error(`[daemon] inloggning misslyckades: ${(e as Error).message}`);
      process.exit(1);
    }
  }

  // Sessionsval: --new -> ny parallell session; annars återuppta den senaste.
  const isNew = has("--new") || !creds!.lastSessionId;
  const sessionId = isNew ? randomUUID() : creds!.lastSessionId!;
  creds!.lastSessionId = sessionId;
  saveCreds(creds!);

  console.log(`[daemon] ${isNew ? "ny" : "återupptar"} session ${sessionId.slice(0, 8)} (${clientName})`);
  runAgent(wsBase, creds!.token, sessionId, clientName);
}

/* ----------------------------- agent + WS-loop ----------------------------- */

function runAgent(wsUrl: string, token: string, sessionId: string, clientName: string): void {
  const AGENT_ARGS = process.env.AGENT_ARGS ? process.env.AGENT_ARGS.split(" ").filter(Boolean) : [];
  const AGENT_CWD = process.env.AGENT_CWD ?? process.cwd();
  const HOOK_DEFAULT: "allow" | "deny" = process.env.AGENT_HELM_HOOK_DEFAULT === "deny" ? "deny" : "allow";
  const HOOK_TIMEOUT = Number(process.env.AGENT_HELM_HOOK_TIMEOUT ?? 120000);
  // Explicit hook-port om satt; annars en ledig (ephemeral) port så flera
  // instanser på samma host inte krockar. Faktiska porten skickas till agenten.
  const explicitHookPort = process.env.AGENT_HELM_HOOK_PORT ? Number(process.env.AGENT_HELM_HOOK_PORT) : 0;
  const COLS = 100;
  const ROWS = 30;

  let ws: WebSocket | null = null;
  let reconnectTimer: ReturnType<typeof setTimeout> | null = null;
  let authFailed = false;
  let pty: IPty | null = null;
  let started = false;
  const pending = new Map<string, (d: Decision) => void>();

  function send(msg: DaemonMessage): void {
    if (ws && ws.readyState === WebSocket.OPEN) ws.send(JSON.stringify(msg));
  }

  function connect(): void {
    console.log(`[daemon] ansluter till ${wsUrl} …`);
    ws = new WebSocket(wsUrl);
    ws.on("open", () => {
      send({ type: "daemon:hello", token, sessionId, clientName, cols: COLS, rows: ROWS });
    });
    ws.on("message", (raw) => {
      const msg = parseMessage<{ type: string; [k: string]: any }>(raw.toString());
      if (!msg) return;
      if (msg.type === "server:input") {
        pty?.write(msg.data);
      } else if (msg.type === "server:approval-decision") {
        const resolve = pending.get(msg.approvalId);
        if (resolve) {
          pending.delete(msg.approvalId);
          resolve({ decision: msg.decision, reason: msg.reason });
        }
      } else if (msg.type === "server:error") {
        console.error(`[daemon] server: ${msg.message}`);
        if (String(msg.message).toLowerCase().includes("token") || String(msg.message).includes("inloggad")) {
          authFailed = true;
          console.error("[daemon] klient-token avvisat — kör 'agent-helm connect --login' för att logga in på nytt.");
        }
      }
    });
    ws.on("close", () => {
      if (authFailed) {
        pty?.kill();
        process.exit(1);
      }
      console.log("[daemon] anslutning stängd — återansluter om 2s");
      scheduleReconnect();
    });
    ws.on("error", (err: Error) => console.error("[daemon] ws-fel:", err.message));
  }

  function scheduleReconnect(): void {
    if (reconnectTimer || authFailed) return;
    reconnectTimer = setTimeout(() => {
      reconnectTimer = null;
      connect();
    }, 2000);
  }

  function startPty(hookPort: number): void {
    if (started) return;
    started = true;
    pty = spawn(AGENT_CMD, AGENT_ARGS, {
      name: "xterm-256color",
      cols: COLS,
      rows: ROWS,
      cwd: AGENT_CWD,
      env: { ...process.env, AGENT_HELM_HOOK_PORT: String(hookPort) } as Record<string, string>,
    });
    console.log(`[daemon] startade '${AGENT_CMD}' (pid ${pty.pid})`);
    pty.onData((data) => send({ type: "daemon:output", data }));
    pty.onExit(({ exitCode }) => {
      console.log(`[daemon] agenten avslutades (kod ${exitCode})`);
      send({ type: "daemon:exit", code: exitCode });
      setTimeout(() => process.exit(exitCode), 200);
    });
    process.on("SIGINT", shutdown);
    process.on("SIGTERM", shutdown);
    connect();
  }

  function shutdown(): void {
    pty?.kill();
    process.exit(0);
  }

  // Lokal hook-endpoint (endast 127.0.0.1). Binds FÖRST så agenten får porten.
  const hookServer = http.createServer((req, res) => {
    if (req.method !== "POST" || req.url !== "/approve") {
      res.writeHead(404);
      res.end();
      return;
    }
    let body = "";
    req.on("data", (c) => (body += c));
    req.on("end", () => {
      let parsed: { toolName?: string; toolInput?: unknown } = {};
      try {
        parsed = JSON.parse(body);
      } catch {
        /* tom */
      }
      const toolName = parsed.toolName ?? "okänt verktyg";
      const approvalId = randomUUID();
      const finish = (d: Decision) => {
        if (res.writableEnded) return;
        res.writeHead(200, { "content-type": "application/json" });
        res.end(JSON.stringify(d));
      };
      if (!ws || ws.readyState !== WebSocket.OPEN) {
        finish({ decision: HOOK_DEFAULT });
        return;
      }
      const timer = setTimeout(() => {
        if (pending.delete(approvalId)) finish({ decision: HOOK_DEFAULT, reason: "timeout" });
      }, HOOK_TIMEOUT);
      pending.set(approvalId, (d) => {
        clearTimeout(timer);
        finish(d);
      });
      send({ type: "daemon:approval", approvalId, toolName, toolInput: parsed.toolInput });
    });
  });
  hookServer.on("error", (e: NodeJS.ErrnoException) => {
    console.error(`[daemon] kunde inte binda hook-porten (${e.code ?? e.message}) — kör utan hook (default: ${HOOK_DEFAULT}).`);
    startPty(explicitHookPort || HOOK_PORT);
  });
  hookServer.listen(explicitHookPort, "127.0.0.1", () => {
    const addr = hookServer.address();
    const port = typeof addr === "object" && addr ? addr.port : explicitHookPort;
    console.log(`[daemon] hook-endpoint på 127.0.0.1:${port} (default vid ingen UI: ${HOOK_DEFAULT})`);
    startPty(port);
  });
}

/* --------------------------------- hook-läge ------------------------------- */

function readStdin(): Promise<string> {
  return new Promise((resolve) => {
    let data = "";
    process.stdin.setEncoding("utf8");
    process.stdin.on("data", (c) => (data += c));
    process.stdin.on("end", () => resolve(data));
    setTimeout(() => resolve(data), 1500);
  });
}

async function runHookMode(): Promise<void> {
  const raw = await readStdin();
  let payload: Record<string, unknown> = {};
  try {
    payload = raw ? (JSON.parse(raw) as Record<string, unknown>) : {};
  } catch {
    payload = {};
  }
  const p = payload as Record<string, any>;
  const toolName: string = p.tool_name ?? p.toolName ?? p.tool?.name ?? p.name ?? "okänt verktyg";
  const toolInput: unknown = p.tool_input ?? p.toolInput ?? p.tool?.input ?? p.arguments ?? p.args ?? payload;

  const decision = await askDaemon(toolName, toolInput);
  if (decision.decision === "deny") {
    process.stdout.write(JSON.stringify({ decision: "deny", reason: decision.reason ?? "Nekat via agent-helm" }));
  } else {
    process.stdout.write(JSON.stringify({ decision: "allow" }));
  }
  process.exit(0);
}

function askDaemon(toolName: string, toolInput: unknown): Promise<Decision> {
  return new Promise((resolve) => {
    const body = JSON.stringify({ toolName, toolInput });
    const req = http.request(
      {
        host: "127.0.0.1",
        port: HOOK_PORT,
        path: "/approve",
        method: "POST",
        headers: { "content-type": "application/json", "content-length": Buffer.byteLength(body) },
      },
      (res) => {
        let out = "";
        res.on("data", (c) => (out += c));
        res.on("end", () => {
          try {
            resolve(JSON.parse(out) as Decision);
          } catch {
            resolve({ decision: "allow" });
          }
        });
      },
    );
    req.on("error", () => resolve({ decision: "allow" }));
    req.setTimeout(180000, () => {
      req.destroy();
      resolve({ decision: "allow" });
    });
    req.write(body);
    req.end();
  });
}

/* --------------------------------- dispatch -------------------------------- */
// VIKTIGT: körs sist, efter att alla module-level const (CONFIG_DIR/CRED_FILE …)
// och funktioner initierats. Annars skulle runConnect:s synkrona del (fram till
// första await) köras under modul-init och läsa dessa const i TDZ → loadCreds()
// får en undefined path → returnerar null → onödigt nytt device-flöde.
const cmd = process.argv[2];
if (cmd === "hook") void runHookMode();
else if (cmd === "logout") logout();
else if (cmd === "whoami") whoami();
else void runConnect();