// Sample data matching the API contract. Timestamps are relative to page load so it always looks "live".
const now = Date.now();
const MIN = 60_000;
const HR = 60 * MIN;
const DAY = 24 * HR;
const iso = (offsetMs) => new Date(now + offsetMs).toISOString();

// every_h drives the generated run history; it isn't part of the API.
const JOBS = [
  {
    id: 1, company_name: 'Acme Corp', job_name: 'File Server – Nightly', status: 'success', every_h: 24,
    last_run_at: iso(-6 * HR), next_run_at: iso(18 * HR),
    message: 'Job completed successfully. 1,284 files processed.',
    source_system: 'Veeam B&R', duration_seconds: 2840, size_bytes: 128_849_018_880,
  },
  {
    id: 2, company_name: 'Acme Corp', job_name: 'SQL01 – Transaction Logs', status: 'warning', every_h: 1,
    last_run_at: iso(-25 * MIN), next_run_at: iso(35 * MIN),
    message: 'Processing SQL01 Warning:\nFailed to truncate transaction logs for database "ERP_PROD".\nLog backup completed but truncation was skipped.',
    source_system: 'Veeam B&R', duration_seconds: 312, size_bytes: 2_147_483_648,
    details: { retry_count: 0, repository: 'REPO-ONSITE-01' },
  },
  {
    // Running now; "last run" is still the previous completion
    id: 7, company_name: 'Acme Corp', job_name: 'Hyper-V Hosts – Daily', status: 'running', every_h: 24,
    running_since: iso(-12 * MIN), last_status: 'success',
    last_run_at: iso(-DAY + 40 * MIN), next_run_at: iso(DAY - 12 * MIN),
    message: 'Completed successfully. 6 VMs processed.',
    source_system: 'Veeam B&R', duration_seconds: 3120, size_bytes: 412_316_860_416,
  },
  {
    id: 3, company_name: 'Bluewater Dental', job_name: 'Workstations – Daily', status: 'failed', every_h: 24,
    last_run_at: iso(-3 * HR), next_run_at: iso(21 * HR),
    message: 'Error: Unable to connect to backup repository \\\\NAS02\\Backups.\nThe network path was not found. (0x80070035)\nJob terminated after 3 retries.',
    source_system: 'Datto', duration_seconds: 95,
    details: { retry_count: 3, target: '\\\\NAS02\\Backups' },
  },
  {
    id: 4, company_name: 'Bluewater Dental', job_name: 'Imaging Server – Hourly', status: 'success', every_h: 1,
    last_run_at: iso(-50 * MIN), next_run_at: iso(10 * MIN),
    message: 'Completed.', source_system: 'Datto', duration_seconds: 420, size_bytes: 8_589_934_592,
  },
  {
    // Green status but next run is in the past → should show as Overdue
    id: 5, company_name: 'Northfield Logistics', job_name: 'Exchange – Nightly', status: 'success', every_h: 24,
    last_run_at: iso(-30 * HR), next_run_at: iso(-6 * HR),
    message: 'Completed successfully.', source_system: 'Acronis', duration_seconds: 5400,
  },
  {
    // Never run / unrecognised status → rendered as Unknown
    id: 6, company_name: 'Northfield Logistics', job_name: 'New NAS – Weekly', status: null,
    last_run_at: null, next_run_at: iso(2 * DAY),
    message: '', source_system: 'Synology Hyper Backup',
  },
];

const MESSAGES = {
  success: 'Job completed successfully.',
  warning: 'Completed with warnings: 1 file skipped (file in use).',
  failed: 'Error: Target repository unreachable. Job terminated.',
};

// Deterministic pseudo-random so history doesn't reshuffle on every modal open
function rng(seed) {
  let x = seed;
  return () => ((x = (x * 1_103_515_245 + 12_345) % 2_147_483_648) / 2_147_483_648);
}

const RUNS = new Map(); // job id → runs, newest first
for (const job of JOBS) {
  const runs = [];
  if (job.running_since) {
    runs.push({ id: `${job.id}-r`, status: 'running', started_at: job.running_since, finished_at: null, message: 'In progress…' });
  }
  if (job.last_run_at && job.every_h) {
    const rand = rng(job.id * 7919);
    const dur = (job.duration_seconds ?? 600) * 1000;
    let end = Date.parse(job.last_run_at);
    for (let i = 0; end - dur > now - 30 * DAY; i++, end -= job.every_h * HR) {
      const r = rand();
      const status = i === 0 ? (job.last_status ?? job.status) : r < 0.03 ? 'failed' : r < 0.1 ? 'warning' : 'success';
      const thisDur = dur * (0.8 + rand() * 0.4);
      runs.push({
        id: `${job.id}-${i}`,
        status,
        started_at: new Date(end - thisDur).toISOString(),
        finished_at: new Date(end).toISOString(),
        duration_seconds: Math.round(thisDur / 1000),
        size_bytes: status === 'failed' ? null : job.size_bytes,
        message: i === 0 ? job.message : MESSAGES[status],
        details: i === 0 ? job.details ?? {} : {},
      });
    }
  }
  RUNS.set(String(job.id), runs);
}

const delay = (ms) => new Promise((r) => setTimeout(r, ms));
const summary = ({ details, every_h, last_status, duration_seconds, size_bytes, ...rest }) => rest;

export const mockApi = {
  async listJobs() {
    await delay(250);
    return { generated_at: new Date().toISOString(), jobs: JOBS.map(summary) };
  },
  async getJob(id) {
    await delay(200);
    const job = JOBS.find((j) => String(j.id) === String(id));
    if (!job) throw new Error('Job not found');
    const { every_h, ...rest } = job;
    return { last_status: job.status === 'running' ? null : job.status, ...rest, details: job.details ?? {} };
  },
  async listRuns(id, days) {
    await delay(300);
    const since = now - days * DAY;
    const runs = (RUNS.get(String(id)) ?? [])
      .filter((r) => Date.parse(r.started_at) >= since)
      .map(({ message, details, ...r }) => r);
    return { job_id: id, since: new Date(since).toISOString(), runs };
  },
  async getRun(id) {
    await delay(150);
    for (const runs of RUNS.values()) {
      const run = runs.find((r) => r.id === id);
      if (run) return { details: {}, ...run };
    }
    throw new Error('Run not found');
  },
};