import * as fs from "node:fs";
import * as path from "node:path";
import { emitChannelEvent, type ChannelEvent } from "./channel.js";

export type MissionHeartbeatStatus = "idle" | "working" | "blocked" | "done" | "error";

export interface MissionHeartbeatOptions {
  id: string;
  name?: string;
  status: MissionHeartbeatStatus;
  currentTask?: string;
  tasksCompleted?: number;
  totalCost?: number;
  runId?: string;
  channelRoot?: string;
  url?: string;
  secret?: string;
  out?: string;
  now?: Date;
  fetcher?: (url: string, init: { method: string; headers: Record<string, string>; body: string }) => Promise<{ status: number }>;
}

export interface MissionHeartbeatReceipt {
  created_at: string;
  payload: {
    id: string;
    name?: string;
    status: MissionHeartbeatStatus;
    currentTask?: string;
    tasksCompleted: number;
    totalCost: number;
  };
  channel_event: ChannelEvent;
  remote_attempted: boolean;
  remote_status?: number;
  remote_ok: boolean;
  reason?: string;
}

export async function sendMissionHeartbeat(opts: MissionHeartbeatOptions): Promise<MissionHeartbeatReceipt> {
  const payload = {
    id: opts.id,
    name: opts.name,
    status: opts.status,
    currentTask: opts.currentTask,
    tasksCompleted: opts.tasksCompleted ?? 0,
    totalCost: opts.totalCost ?? 0,
  };
  const now = opts.now ?? new Date();
  const event = emitChannelEvent(opts.runId ?? opts.id, { source: "mission", type: "output", data: payload }, opts.channelRoot, now);
  const receipt: MissionHeartbeatReceipt = { created_at: now.toISOString(), payload, channel_event: event, remote_attempted: false, remote_ok: false };

  if (opts.url && opts.secret) {
    receipt.remote_attempted = true;
    try {
      const res = await (opts.fetcher ?? fetchStatus)(opts.url, {
        method: "POST",
        headers: { "Content-Type": "application/json", Authorization: `Bearer ${opts.secret}` },
        body: JSON.stringify(payload),
      });
      receipt.remote_status = res.status;
      receipt.remote_ok = res.status >= 200 && res.status < 300;
      if (!receipt.remote_ok) receipt.reason = `HTTP ${res.status}`;
    } catch (error) {
      receipt.reason = error instanceof Error ? error.message : String(error);
    }
  } else {
    receipt.reason = "remote skipped: missing url or secret";
  }

  if (opts.out) writeMissionHeartbeatReceipt(opts.out, receipt);
  return receipt;
}

export function writeMissionHeartbeatReceipt(file: string, receipt: MissionHeartbeatReceipt): void {
  fs.mkdirSync(path.dirname(file), { recursive: true });
  fs.writeFileSync(file, `${JSON.stringify(receipt, null, 2)}\n`);
}

async function fetchStatus(url: string, init: { method: string; headers: Record<string, string>; body: string }) {
  return fetch(url, init);
}