import { tileBounds } from '../../../src/layers/streetLevel/tileMath.js';
import { metresApart, photoJpeg } from './mapillaryGraph.mjs';

/**
 * KartaView's API, image proxy and photo storage answered from fixtures, so
 * the gate's KartaView steps need no network. One drive runs north along
 * KV_LINE; every tenth photo is a 360° one. Photos live on storage2 while
 * their `fileurl*` name storage1, as KartaView's API does, so the gate also
 * proves the provider builds addresses from `storage`. Every odd-indexed
 * photo is archived (storage answers 409, the image proxy still serves it),
 * so the nearest photo opened is even and › must skip the one after it. The
 * first nearest-photo lookup is rate-limited (429, Retry-After: 0), as
 * KartaView does under load.
 */

export const KV_SEQUENCE_ID = '900001';
export const KV_LINE = Object.freeze({
  lon: -121.4931,
  south: 38.5795,
  north: 38.5875,
});
const KV_SPACING_M = 25;
const METRES_PER_DEG_LAT = 110_540;
const SHOT = '2024-05-02 16:20:00.000';

const CORS = Object.freeze({ 'Access-Control-Allow-Origin': '*' });

/** Lookups answered so far: the first one is rate-limited. */
let nearestLookups = 0;

/** Forget the lookups answered, so the next one is rate-limited again. */
export function resetKartaViewFixture() {
  nearestLookups = 0;
}

/** The drive's photos, south to north; every tenth is 360°, every odd one archived. */
export function kartaViewPhotos() {
  const step = KV_SPACING_M / METRES_PER_DEG_LAT;
  const count = Math.floor((KV_LINE.north - KV_LINE.south) / step) + 1;
  return Array.from({ length: count }, (_, i) => ({
    id: String(77_000_000 + i),
    index: i,
    lon: KV_LINE.lon,
    lat: Number((KV_LINE.south + i * step).toFixed(7)),
    isPano: i % 10 === 5,
    archived: i % 2 === 1,
  }));
}

function record(photo) {
  const name = `${KV_SEQUENCE_ID}_${photo.id}.jpg`;
  const folder = photo.isPano ? 'wrapped_proc' : 'proc';
  const path = (prefix) => `2024/5/2/${prefix}/${name}`;
  const storage1 = (prefix) =>
    `https://storage1.openstreetcam.org/files/photo/${path(prefix)}`;
  return {
    id: photo.id,
    sequenceId: KV_SEQUENCE_ID,
    sequenceIndex: String(photo.index),
    lat: String(photo.lat),
    lng: String(photo.lon),
    matchLat: String(photo.lat),
    matchLng: String(photo.lon),
    heading: '0',
    fieldOfView: photo.isPano ? '360' : '0',
    projection: photo.isPano ? 'SPHERE' : 'PLANE',
    shotDate: SHOT,
    dateAdded: SHOT,
    storage: 'storage2',
    filepath: path('{{sizeprefix}}'),
    filepathLTh: path('lth'),
    filepathProc: path(folder),
    fileurl: storage1('{{sizeprefix}}'),
    fileurlLTh: storage1('lth'),
    fileurlProc: storage1(folder),
  };
}

const ok = (result) => ({
  status: 200,
  contentType: 'application/json',
  headers: CORS,
  body: JSON.stringify({ status: { apiCode: 600, httpCode: 200 }, result }),
});
const raw = (status, body) => ({
  status,
  contentType: 'application/json',
  headers: CORS,
  body: JSON.stringify(body),
});

/** The drive's track inside tile `z/x/y` (with a small margin), as KartaView's JSON tile. */
function tileLines(z, x, y) {
  const { west, east, south, north } = tileBounds(x, y, z);
  if (KV_LINE.lon < west || KV_LINE.lon > east) return [];
  const from = Math.max(KV_LINE.south, south);
  const to = Math.min(KV_LINE.north, north);
  if (from >= to) return [];
  // Two segments meeting end to start, as KartaView splits ways.
  const mid = (from + to) / 2;
  const at = (lat) => ({ lat: String(lat), lng: String(KV_LINE.lon) });
  return [
    { track: [at(from), at(mid)], matched: '1' },
    { track: [at(mid), at(to)], matched: '1' },
  ];
}

/** A call named by host, path shape and parameter names. */
export function describeKartaViewCall(method, url) {
  const keys = [...url.searchParams.keys()].sort();
  const path = url.pathname
    .replace(/\/tiles\/\d+\/\d+\/\d+\.json$/, '/tiles/{x}/{y}/{z}.json')
    .replace(/\/photo\/\d+$/, '/photo/{id}')
    .replace(/\/sequence\/\d+\/photos$/, '/sequence/{id}/photos')
    .replace(/^\/files\/photo\/.*$/, '/files/photo/{path}')
    .replace(
      /^\/pr:sharp\/rs:fit:\d+:\d+\/.*$/,
      '/pr:sharp/rs:fit:{w}:{h}/{address}',
    );
  return `${method} ${url.hostname}${path}${keys.length ? `?${keys.join('&')}` : ''}`;
}

/**
 * Answer one KartaView request; `known` is false for a call no fixture
 * covers, so the gate fails on a new one instead of missing it.
 */
export function answerKartaViewRequest({ method, url }) {
  const address = new URL(url);
  const photos = kartaViewPhotos();
  if (method === 'OPTIONS')
    return { status: 204, headers: CORS, body: '', known: true };
  const image = {
    status: 200,
    contentType: 'image/jpeg',
    headers: CORS,
    body: photoJpeg(),
    known: true,
  };
  if (address.hostname === 'cdn.kartaview.org')
    return /^\/pr:sharp\/rs:fit:\d+:\d+\/[\w-]+$/.test(address.pathname)
      ? image
      : { ...raw(404, {}), known: false };
  if (address.hostname === 'storage2.openstreetcam.org') {
    if (!address.pathname.includes(KV_SEQUENCE_ID))
      return { ...raw(404, {}), known: false };
    const archived = photos.some(
      (photo) =>
        photo.archived && address.pathname.endsWith(`_${photo.id}.jpg`),
    );
    // An archived photo's file is gone from storage: KartaView answers 409.
    return archived ? { ...raw(409, {}), known: true } : image;
  }
  if (/^storage\d+\.openstreetcam\.org$/.test(address.hostname))
    // The wrong host the API names: KartaView answers 404 there.
    return { ...raw(404, {}), known: false };
  if (address.hostname !== 'api.kartaview.org')
    return { ...raw(404, {}), known: false };
  const path = address.pathname;
  const tile = path.match(
    /^\/2\.0\/sequence\/tiles\/(\d+)\/(\d+)\/(\d+)\.json$/,
  );
  if (tile)
    return {
      ...raw(200, {
        lines: tileLines(Number(tile[3]), Number(tile[1]), Number(tile[2])),
      }),
      known: true,
    };
  if (path === '/2.0/photo/') {
    if (nearestLookups++ === 0)
      return {
        ...raw(429, {}),
        headers: {
          ...CORS,
          'Retry-After': '0',
          'Access-Control-Expose-Headers': 'Retry-After',
        },
        known: true,
      };
    const q = address.searchParams;
    const at = { lat: Number(q.get('lat')), lon: Number(q.get('lng')) };
    const near = photos
      .map((photo) => ({ photo, metres: metresApart(at, photo) }))
      .filter(({ metres }) => metres < 200)
      .sort((a, b) => a.metres - b.metres)
      .slice(0, Number(q.get('itemsPerPage')) || 10)
      .map(({ photo, metres }) => ({
        ...record(photo),
        distance: metres.toFixed(2),
      }));
    return { ...ok({ data: near, hasMoreData: false }), known: true };
  }
  const one = path.match(/^\/2\.0\/photo\/(\d+)$/);
  if (one) {
    const photo = photos.find((p) => p.id === one[1]);
    return photo
      ? { ...ok({ data: record(photo) }), known: true }
      : { ...raw(200, { status: { apiCode: 601 }, result: {} }), known: true };
  }
  const page = path.match(/^\/2\.0\/sequence\/(\d+)\/photos$/);
  if (page) {
    const q = address.searchParams;
    const size = Number(q.get('itemsPerPage')) || 100;
    const number = Number(q.get('page')) || 1;
    const rows = page[1] === KV_SEQUENCE_ID ? photos : [];
    return {
      ...ok({
        data: rows.slice((number - 1) * size, number * size).map(record),
        hasMoreData: number * size < rows.length,
      }),
      known: true,
    };
  }
  return { ...raw(404, {}), known: false };
}