const jobs = {};
const MAX_LOG_LINES = 120;

function listJobs() {
  return Object.values(jobs)
    .sort((a, b) => String(b.startedAt || "").localeCompare(String(a.startedAt || "")));
}

function getJob(jobId) {
  return jobs[jobId] || null;
}

function canStartJob(shop) {
  if (!shop) {
    return false;
  }

  const existing = jobs[shop];
  return !existing || existing.status === "done" || existing.status === "error";
}

function createJob(payload = {}) {
  const id = String(payload.shop || "").trim();
  if (!id) {
    throw new Error("Shop is required to create a job.");
  }

  jobs[id] = {
    id,
    status: "queued",
    step: "queued",
    stepIndex: 0,
    totalSteps: 6,
    detail: null,
    summary: null,
    error: null,
    logs: [],
    liveStats: {},
    payload,
    startedAt: new Date().toISOString(),
    updatedAt: new Date().toISOString(),
  };
  return jobs[id];
}

function updateJob(jobId, patch) {
  const current = jobs[jobId];
  if (!current) {
    return null;
  }

  jobs[jobId] = {
    ...current,
    ...patch,
    liveStats: {
      ...(current.liveStats || {}),
      ...(patch.liveStats || {}),
    },
    updatedAt: new Date().toISOString(),
  };

  return jobs[jobId];
}

function appendJobLog(jobId, line, extraPatch = {}) {
  const current = jobs[jobId];
  if (!current) {
    return null;
  }

  const nextLogs = [...(current.logs || []), {
    at: new Date().toISOString(),
    line,
  }].slice(-MAX_LOG_LINES);

  jobs[jobId] = {
    ...current,
    ...extraPatch,
    liveStats: {
      ...(current.liveStats || {}),
      ...(extraPatch.liveStats || {}),
    },
    logs: nextLogs,
    updatedAt: new Date().toISOString(),
  };

  return jobs[jobId];
}

module.exports = {
  listJobs,
  getJob,
  canStartJob,
  createJob,
  updateJob,
  appendJobLog,
};