// PROCITY CityGen — the OSM plan source (Lane A, round 6). Second producer behind the same
// CityPlan contract as plan.js, so Lanes B–F consume it unchanged. Selected via ?plansrc=osm
// (default stays 'synthetic', byte-identical — see index.js `generatePlanFor`).
//
// Input: a CHECKED-IN fixture of real inner-Melbourne secondhand/charity/music/book/toy/antique
// shops (osm_fixture.js, extracted from thriftgod's Overpass cache). ZERO network at runtime.
//
// How real data drives the plan (documented simplification — the honest "cut"): a shop's real
// LATITUDE picks which east–west avenue it lands on, and its real LONGITUDE sets its order along
// that avenue. Avenue spacing and per-lot frontage are regularized (marched) so the result is a
// clean, non-overlapping, valid CityPlan — the geography is real in row+order, stylized in metres.
// A future pass can honour exact projected positions; this lands a booting, invariants-green seam.

import { rng, seedFor, mulberry32, pick, frange } from '../core/prng.js';
import { SHOP_TYPES } from '../core/registry.js';
import { OSM_TOWNS, DEFAULT_TOWN } from './osm_fixture.js';

const r2 = v => Math.round(v * 100) / 100;
const r4 = v => Math.round(v * 10000) / 10000;
const clampHour = h => Math.max(0, Math.min(23, h | 0));
const LATE_HOUR = 22;                       // matches plan.js: exactly one shop closes ≥ this

const EARTH_M = 111320;                      // metres per degree latitude (equirectangular)
const ROWS = 8;                              // latitude bands → avenues
const ROW_DZ = 54;                           // metres between avenues (> avenue depth ⇒ blocks disjoint)
const AV_W = 12, SPINE_W = 24;               // corridor widths
const SPINE_CLEAR = 16;                      // lots start this far east of the spine (no lot on the road)
const GAP = 2, DEPTH = 14;                   // lot gap + depth along/into the avenue

// Short signboard form from a real shop name: drop a leading "The", take words up to ~15 chars.
function signOf(name) {
  const words = String(name).replace(/^the\s+/i, '').split(/\s+/);
  let s = '';
  for (const w of words) { if ((s + ' ' + w).trim().length > 15) break; s = (s + ' ' + w).trim(); }
  return (s || String(name).slice(0, 15)).toUpperCase();
}

// ── the TOWN-CACHE CONTRACT (ROUND17 ledger #6, Lane A owns it) ─────────────────────────────────────
// What `plan_osm` accepts. E's pipeline (build_towns.py) produces one JSON per real town under
// web/assets/towns/<key>.json in THIS shape; plan_osm marches it exactly like the checked-in fixtures —
// the scout proves the EXISTING contract eats real data, no new plan fields, no new geometry.
//
//   { schema:"procity-town-cache/1", key, town, source:"osm",
//     license, attribution,                     // ODbL — REQUIRED on shipped real caches (+ SOURCES.md, E)
//     center:{lat,lon},                         // REQUIRED — equirectangular projection origin
//     bbox?, counts?, fetchedAt?,               // optional provenance/metadata (geometry ignores these)
//     shops:[ { id, name, type, lat, lon, suburb? } ] }   // REQUIRED, >= MIN_TOWN_SHOPS
//
// `type` SHOULD be a registry SHOP_TYPE; an unknown OSM kind remaps to 'opshop' (a warning, absorbed —
// same as the fixtures). A blank name defaults to the type label. `suburb` is optional.
export const TOWN_CACHE_SCHEMA = 'procity-town-cache/1';
export const MIN_TOWN_SHOPS = 6;   // functional floor: up to 4 venues + the one openLate landmark + a spare
export const MAX_TOWN_SPAN_M = 5000; // a cache should be ONE compact town, not a region (see R17 risk note)
const isNum = v => typeof v === 'number' && Number.isFinite(v);

// Validate a cache against the contract. { ok, errors[], warnings[] } — errors mean plan_osm would not
// boot a valid district; warnings are absorbed (remapped type, defaulted name, missing licence).
export function validateTownCache(cache) {
  const errors = [], warnings = [];
  if (!cache || typeof cache !== 'object') return { ok: false, errors: ['cache is not an object'], warnings };
  if (cache.schema && cache.schema !== TOWN_CACHE_SCHEMA) warnings.push(`schema '${cache.schema}' != '${TOWN_CACHE_SCHEMA}'`);
  const c = cache.center;
  if (!c || !isNum(c.lat) || !isNum(c.lon)) errors.push('center.{lat,lon} must be finite numbers');
  if (!Array.isArray(cache.shops)) errors.push('shops must be an array');
  else {
    if (cache.shops.length < MIN_TOWN_SHOPS) errors.push(`>= ${MIN_TOWN_SHOPS} shops required (got ${cache.shops.length})`);
    let badCoord = 0, blankName = 0, unknownType = 0, dupId = 0; const ids = new Set();
    for (const s of cache.shops) {
      if (!s || !isNum(s.lat) || !isNum(s.lon)) badCoord++;
      if (!s || !(typeof s.name === 'string' && s.name.trim())) blankName++;
      if (!s || !SHOP_TYPES[s.type]) unknownType++;
      if (s) { if (ids.has(s.id)) dupId++; else ids.add(s.id); }
    }
    if (badCoord) errors.push(`${badCoord} shop(s) with non-finite lat/lon`);
    if (blankName) warnings.push(`${blankName} blank shop name(s) → defaulted to type label`);
    if (unknownType) warnings.push(`${unknownType} unknown shop type(s) → remapped to opshop`);
    if (dupId) warnings.push(`${dupId} duplicate shop id(s)`);
    // wide-spread warning: an over-broad Overpass bbox marches into an unusable multi-km strip (the R17
    // real-data risk). Metadata only — plan_osm still boots a valid plan; it just isn't a coherent town.
    let mnLat = Infinity, mxLat = -Infinity, mnLon = Infinity, mxLon = -Infinity;
    for (const s of cache.shops) if (s && isNum(s.lat) && isNum(s.lon)) {
      mnLat = Math.min(mnLat, s.lat); mxLat = Math.max(mxLat, s.lat);
      mnLon = Math.min(mnLon, s.lon); mxLon = Math.max(mxLon, s.lon);
    }
    if (mxLat > mnLat) {
      const latM = (mxLat - mnLat) * 111320, lonM = (mxLon - mnLon) * 111320 * Math.cos((c && c.lat || 0) * Math.PI / 180);
      if (Math.max(latM, lonM) > MAX_TOWN_SPAN_M) warnings.push(`shops span ${(Math.max(latM, lonM) / 1000).toFixed(1)} km — likely more than one town (bound the query tighter)`);
    }
  }
  if (!cache.license || !cache.attribution) warnings.push('missing license/attribution (ODbL required for shipped real caches)');
  return { ok: errors.length === 0, errors, warnings };
}

// A runtime registry of validated town caches (E's real caches; the selfcheck + shell register them).
// generatePlanOSM resolves a town from opts.cache, then this registry, then the checked-in fixtures.
const TOWN_CACHES = {};
export function registerTownCache(key, cache) {
  const v = validateTownCache(cache);
  if (!v.ok) throw new Error(`town cache '${key}' invalid: ${v.errors.join('; ')}`);
  TOWN_CACHES[key] = cache;
  return v;
}

export function generatePlanOSM(citySeed, town = DEFAULT_TOWN, opts = {}) {
  citySeed = (citySeed >>> 0);
  const fx = opts.cache || TOWN_CACHES[town] || OSM_TOWNS[town] || OSM_TOWNS[DEFAULT_TOWN];
  // Normalization log: what the importer had to bend to fit the CityPlan contracts (real OSM data
  // "doesn't bend the contract"). Surfaced via opts.report (selfcheck prints it) — never on the plan.
  const norm = { town: fx.town, source: 'osm', shops: fx.shops.length, typesRemapped: 0, hoursClamped: 0, openLate: 'video' };

  const nodes = [], edges = [], districts = [], blocks = [], lots = [], shops = [];
  let nid = 0, eid = 0, did = 0, bid = 0, lid = 0, sid = 0;
  const addNode = (x, z) => { const n = { id: nid++, x: r2(x), z: r2(z) }; nodes.push(n); return n; };
  const addEdge = (a, b, width, kind) => { const id = eid++; edges.push({ id, a, b, width, kind }); return id; };
  const addDistrict = (kind, cx, cz) => { const id = did++; districts.push({ id, kind, cx: r2(cx), cz: r2(cz) }); return id; };
  const addBlock = (district, kind, poly) => { const id = bid++; blocks.push({ id, district, kind, poly: poly.map(p => [r2(p[0]), r2(p[1])]) }); return id; };
  const addLot = (block, x, z, w, d, ry, frontEdge, use) => {
    const id = lid++;
    lots.push({ id, block, x: r2(x), z: r2(z), w: r2(w), d: r2(d), ry: r4(ry), frontEdge, use });
    return id;
  };

  // Create a shop record from a real fixture entry (real name; seeded facade/hours/storeys).
  function addShop(lotId, fixtureShop) {
    const id = sid++;
    const type = SHOP_TYPES[fixtureShop.type] ? fixtureShop.type : 'opshop';
    if (type !== fixtureShop.type) norm.typesRemapped++; // unknown OSM kind → opshop (normalization)
    const reg = SHOP_TYPES[type];
    const seed = seedFor(citySeed, 'osmshop', fixtureShop.id);
    const sr = mulberry32(seed);
    const facadeSkin = pick(sr, reg.facades);
    const storeys = reg.storeys[0] + ((sr() * (reg.storeys[1] - reg.storeys[0] + 1)) | 0);
    let open = reg.hours.open, close = reg.hours.close;
    if (sr() < 0.3) open = clampHour(open + (sr() < 0.5 ? -1 : 1));
    if (sr() < 0.3) close = clampHour(close + (sr() < 0.5 ? -1 : 1));
    if (close <= open) close = clampHour(open + 2);
    if (close > LATE_HOUR - 1) norm.hoursClamped++;
    close = Math.min(close, LATE_HOUR - 1);   // only the openLate landmark reaches ≥ LATE_HOUR
    // real OSM data has the odd unnamed shop — default a blank name to the registry label so the sign
    // never renders "undefined" (build_towns.py filters most, but plan_osm must not trust its input).
    const nm = (typeof fixtureShop.name === 'string' && fixtureShop.name.trim()) ? fixtureShop.name : (reg.label || type);
    if (nm !== fixtureShop.name) norm.namesDefaulted = (norm.namesDefaulted || 0) + 1;
    shops.push({ id, lot: lotId, type, name: nm, sign: signOf(nm),
      seed, facadeSkin, storeys, hours: [open, close] });
    return id;
  }

  // ── project real shops → local metres; bin by latitude into avenue rows, order by longitude ──
  const cosLat = Math.cos(fx.center.lat * Math.PI / 180);
  const pts = fx.shops.map(s => ({
    s, x: (s.lon - fx.center.lon) * EARTH_M * cosLat, z: (s.lat - fx.center.lat) * EARTH_M,
  }));
  const zMin = Math.min(...pts.map(p => p.z)), zMax = Math.max(...pts.map(p => p.z));
  const span = (zMax - zMin) || 1;
  const rowsArr = Array.from({ length: ROWS }, () => []);
  for (const p of pts) {
    const row = Math.min(ROWS - 1, Math.max(0, Math.floor((p.z - zMin) / span * ROWS)));
    rowsArr[row].push(p);
  }

  const district = addDistrict('mainstreet', 0, 0);
  // spine: one main street running S→N through the origin, a node per (occupied) row
  const spineNodes = [];
  const usedRows = rowsArr.map((r, i) => ({ r, i })).filter(o => o.r.length);
  usedRows.forEach((o, k) => { o.zPos = (k - (usedRows.length - 1) / 2) * ROW_DZ; spineNodes.push(addNode(0, o.zPos)); });
  const spineEdges = [];
  for (let k = 0; k < spineNodes.length - 1; k++) spineEdges.push(addEdge(spineNodes[k].id, spineNodes[k + 1].id, SPINE_W, 'main'));

  // ── each row → an east–west avenue off the spine; its shops march into non-overlapping lots ──
  usedRows.forEach((o, k) => {
    const rowShops = o.r.slice().sort((a, b) => a.x - b.x || a.s.id - b.s.id); // real longitude order, id tiebreak
    const zPos = o.zPos;
    // frontages from each shop's registry footprint (deterministic mid-band, no rng needed here)
    const fr = rowShops.map(p => { const fp = SHOP_TYPES[p.s.type]?.footprint || { fmin: 7, fmax: 10 }; return (fp.fmin + fp.fmax) / 2; });
    const avLen = SPINE_CLEAR + fr.reduce((s, f) => s + f + GAP, 0) + 6;
    const west = addNode(0, zPos), east = addNode(avLen, zPos);
    const avEdge = addEdge(west.id, east.id, AV_W, 'side');
    // block = the frontage strip on the south side of the avenue
    const half = AV_W / 2, sd = DEPTH + 2;
    const block = addBlock(district, 'mainstreet',
      [[SPINE_CLEAR, zPos - half], [avLen, zPos - half], [avLen, zPos - half - sd], [SPINE_CLEAR, zPos - half - sd]]);
    const ry = Math.atan2(0, -1); // outward normal (street→lot) points south (0,-1) ⇒ facade faces +z (north) to the avenue
    let t = SPINE_CLEAR;
    rowShops.forEach((p, j) => {
      const f = fr[j];
      const cx = t + f / 2;
      const cz = zPos - (half + DEPTH / 2);
      const lot = addLot(block, cx, cz, f, DEPTH, ry, avEdge, 'shop');
      addShop(lot, p.s);
      t += f + GAP;
    });
  });

  // ── exactly one late-night landmark: a video rental, closes ≥ LATE_HOUR (matches synthetic) ──
  if (shops.length) {
    const videos = shops.filter(s => s.type === 'video');
    const pool = videos.length ? videos : shops.filter(s => s.type !== 'stall');
    norm.openLate = videos.length ? 'video' : (pool.length ? pool[0].type + ' (no video in town)' : 'none');
    if (pool.length) {
      const lr = rng(citySeed, 'osm-openlate', 0);
      const chosen = pick(lr, pool);
      chosen.openLate = true;
      chosen.hours = [chosen.hours[0], LATE_HOUR + ((lr() * 2) | 0)];
    }
  }

  // Centre the imported town on the origin and report its true bounding box as `size` (rigid
  // translation ⇒ all invariants preserved; gives the map a framed view and Lane B the real extent).
  let minx = Infinity, maxx = -Infinity, minz = Infinity, maxz = -Infinity;
  for (const l of lots) {
    minx = Math.min(minx, l.x - l.w); maxx = Math.max(maxx, l.x + l.w);
    minz = Math.min(minz, l.z - l.d); maxz = Math.max(maxz, l.z + l.d);
  }
  for (const n of nodes) { minx = Math.min(minx, n.x); maxx = Math.max(maxx, n.x); minz = Math.min(minz, n.z); maxz = Math.max(maxz, n.z); }
  const shx = -r2((minx + maxx) / 2), shz = -r2((minz + maxz) / 2);
  for (const n of nodes) { n.x = r2(n.x + shx); n.z = r2(n.z + shz); }
  for (const l of lots) { l.x = r2(l.x + shx); l.z = r2(l.z + shz); }
  for (const b of blocks) b.poly = b.poly.map(p => [r2(p[0] + shx), r2(p[1] + shz)]);
  for (const d of districts) { d.cx = r2(d.cx + shx); d.cz = r2(d.cz + shz); }
  const M = 40;
  const size = { w: Math.max(256, Math.ceil((maxx - minx) + 2 * M)), d: Math.max(256, Math.ceil((maxz - minz) + 2 * M)) };

  if (opts.report) Object.assign(opts.report, norm); // caller-supplied log sink (selfcheck prints it)

  return {
    version: 1,
    citySeed,
    source: 'osm',            // town key stays OFF the plan (keeps the Melbourne golden frozen); the
    name: fx.town || 'Melbourne', // display name + the selector arg convey which town this is.
    size,
    districts,
    streets: { nodes, edges },
    blocks,
    lots,
    shops,
  };
}

// The catalogue of available OSM town keys (for the shell/map selector + selfcheck iteration).
export function osmTownKeys() { return [...new Set([...Object.keys(OSM_TOWNS), ...Object.keys(TOWN_CACHES)])]; }