// PROCITY CityGen — v3 GIG LAYER (?gigs=1). Post-hoc augmentation: takes a finished CityPlan and adds
// the town's VENUES (2–4: pub / band_room / rsl), the week's gig schedule (`plan.gigs`), and poster
// assignments (`plan.posters`). Applied ONLY when the flag is on (selector: generatePlanFor(..,{gigs:true})),
// so the base plan stays byte-identical and the frozen goldens don't move (CITY_SPEC prime flag law).
//
// Source-agnostic: works on synthetic AND osm plans (it only reads shops/lots/blocks/edges). Deterministic
// from citySeed (+ optional custom band names). NO THREE, no network — pure data (CITY_SPEC law).
//
// ROUND13 (v3.0-beta, the district): one venue → 2–4; one genre → three (by kind); one night's poster run
// → town-wide. See LANE_A_NOTES §Round 13 for the interface C/D/B/F hang off.

import { rng, seedFor, mulberry32, pick, shuffle, irange } from '../core/prng.js';
import { SHOP_TYPES, poleOffset, roadWidth } from '../core/registry.js';
import { shopName, bandName } from './names.js';

const r2 = v => Math.round(v * 100) / 100;
const r4 = v => Math.round(v * 10000) / 10000;

// A venue's own frontage poster seats on the +Z street facade, `d/2 + FACADE_PROUD` out from the lot
// centre (shared by pickVenues' clearance test and buildPosters). ROUND16 (ledger #6): band_room/rsl
// selection prefers a lot whose facade clears every carriageway by ≥ POSTER_CLEAR, so the poster can
// never sit on a back-street's bitumen (a narrow through-lot otherwise abuts the block's other street).
// selfcheck asserts the same floor — import POSTER_CLEAR there, don't re-guess it.
export const POSTER_CLEAR = 0.5;
const FACADE_PROUD = 0.06;
// ROUND20 poster cap: the spine pole run is "2 per main edge", which on a sparse REAL town (few shops, big
// edge graph) reads busy (katoomba: 438). Cap it SCALED BY SHOP COUNT — a seeded subsample of the run. On
// the synthetic town the shop count is in the hundreds, so the cap never binds and the gig golden is frozen.
const POSTER_PER_SHOP = 1.5, POSTER_SPINE_FLOOR = 12;
// nearest point on segment AB to P (same helper the selfcheck uses; kept local so gigs.js stays pure).
const nearestSeg = (px, pz, ax, az, bx, bz) => {
  const dx = bx - ax, dz = bz - az, L2 = dx * dx + dz * dz || 1;
  let t = ((px - ax) * dx + (pz - az) * dz) / L2; t = Math.max(0, Math.min(1, t));
  return [ax + dx * t, az + dz * t];
};

// A night gig: doors at DUSK (seg4), on during NIGHT (seg5) — see lighting.js segment→hour map.
const NIGHTS = 7;
const GIG_START_SEG = 5; // NIGHT (22:00) — gig is "on"
const GIG_END_SEG = 5;   // single coarse night segment; F does doors at startSeg−1 (DUSK)

const VENUES_PER_TOWN = [2, 4];   // seeded count (charter: 2–4 venues per town)
const GIGS_PER_VENUE = [4, 6];    // per week — the rest are dark nights, which read true
// Kind order as venues are added. A town of 4 gets a second pub at the far end of the spine —
// two pubs and a footy club is the most Australian town there is.
const VENUE_SEQUENCE = ['pub', 'band_room', 'rsl', 'pub'];
// ROUND21 (D's relocation finding): a venue 1 km from the retail cluster is a gig with no passing crowd
// (katoomba's pub had 1 shop within 160 m; the RSL had 13). Venue candidates prefer cluster adjacency.
const CLUSTER_R = 160, CLUSTER_MIN = 3;

// Cover law (ROUND13 §A2): ~half free town-wide; the RSL skews CHEAP (it's a club, the bistro pays the
// bills), the band room skews FREE (the door is a hat on a milk crate). `cover` stays an integer in
// {0} ∪ [2,10] for every kind, so F's wallet seam and the selfcheck assert are unchanged.
const COVER_BY_KIND = {
  pub:       { free: 0.50, min: 2, max: 10 },
  band_room: { free: 0.70, min: 2, max: 6 },
  rsl:       { free: 0.45, min: 2, max: 5 },
};

// ── THE gigKey CONTRACT (ROUND13 debt #1) ─────────────────────────────────────────────
// The audio manifest key for a genre IS the gigKey, and it is ALWAYS `gig-<genreKey>`. There is no
// mapping table anywhere: C emits `audio.gigKey`, E names the manifest bed, B's spill reads it and F
// resolves it — all through this one function. R12 lost a gig bed to a private rename (C asked for
// `gig-pubrock`, E shipped `pubrock-live`, and because audio fails soft the band just mimed). One key,
// zero mapping — import this rather than building the string yourself.
export const gigKeyFor = genreKey => `gig-${genreKey}`;

// ── venue selection ───────────────────────────────────────────────────────────────────
// Placement rules (charter + ROUND13 §A1): pub at a spine END (a destination you follow the sound to),
// band_room on the warehouse fringe, RSL off-spine. Each pick converts a plain shop IN PLACE (keeps the
// lot id + geometry ⇒ enterable, no overlap) and never takes the openLate landmark (the video survives).
// Every rule degrades to "any remaining plain shop" so an osm town — which has no warehouse fringe and
// may have no spine at all — still gets its venues.
function pickVenues(plan, citySeed) {
  const lotById = new Map(plan.lots.map(l => [l.id, l]));
  const blockById = new Map(plan.blocks.map(b => [b.id, b]));
  const mainEdges = new Set(plan.streets.edges.filter(e => e.kind === 'main').map(e => e.id));

  const nodeById = new Map(plan.streets.nodes.map(n => [n.id, n]));
  const lotOf = s => lotById.get(s.lot);
  const blockKindOf = s => { const l = lotOf(s), b = l && blockById.get(l.block); return b ? b.kind : null; };
  const onMain = s => { const l = lotOf(s); return !!l && mainEdges.has(l.frontEdge); };
  const dist2 = s => { const l = lotOf(s); return l ? l.x * l.x + l.z * l.z : 0; };
  const farthestFirst = arr => arr.slice().sort((a, b) => dist2(b) - dist2(a) || a.id - b.id);
  // clearance of a shop's +Z frontage-poster point to the nearest carriageway (ROUND16 ledger #6).
  const facadeClear = s => {
    const l = lotOf(s); if (!l) return Infinity;
    const off = l.d / 2 + FACADE_PROUD;
    const px = l.x + Math.sin(l.ry) * off, pz = l.z + Math.cos(l.ry) * off;
    let best = Infinity;
    for (const e of plan.streets.edges) {
      const a = nodeById.get(e.a), b = nodeById.get(e.b); if (!a || !b) continue;
      const [nx, nz] = nearestSeg(px, pz, a.x, a.z, b.x, b.z);
      best = Math.min(best, Math.hypot(px - nx, pz - nz) - roadWidth(e) / 2);
    }
    return best;
  };
  // ROUND21: how many OTHER shops sit within CLUSTER_R of this candidate — its retail-cluster adjacency.
  // Real-data plans only: `plan.source === 'osm'` is undefined on the synthetic generator, so the bias
  // below can never touch the frozen synthetic goldens BY CONSTRUCTION (not by luck — measured: 4
  // synthetic candidates per seed sit under CLUSTER_MIN, so a blanket filter WOULD have moved them).
  const realData = plan.source === 'osm';
  const shopLots = realData ? plan.shops.map(lotOf).filter(Boolean) : [];
  const clusterCount = s => {
    const l = lotOf(s); if (!l) return 0;
    let n = 0;
    for (const o of shopLots) if (o !== l && Math.hypot(o.x - l.x, o.z - l.z) <= CLUSTER_R) n++;
    return n;
  };

  const base = plan.shops.filter(s => {
    if (s.openLate) return false;                 // must not displace the night landmark
    const l = lotOf(s);
    return !!l && l.use === 'shop';               // a plain shop → keeps SOLID + geometry
  });

  const taken = new Set();
  const out = [];
  const n = irange(rng(citySeed, 'venueN', 0), VENUES_PER_TOWN[0], VENUES_PER_TOWN[1]);

  for (let i = 0; i < n; i++) {
    const kind = VENUE_SEQUENCE[i] || 'pub';
    const pool = base.filter(s => !taken.has(s.id));
    if (!pool.length) break;                      // degenerate town — fewer venues, still valid

    // ROUND21 ledger #1: prefer CLUSTER-ADJACENT candidates (the retail heart), then let the kind flavors
    // bias WITHIN that set rather than override it — a fringe band_room in the cluster beats a fringe
    // band_room a kilometre from anyone. A town with no cluster at all falls back to the whole pool.
    let field = pool;
    if (realData) {
      const clustered = pool.filter(s => clusterCount(s) >= CLUSTER_MIN);
      if (clustered.length) field = clustered;
      else {
        // ROUND22 (pack scale): a genuinely thin town can have NO candidate at the floor — ballarat,
        // toowoomba and newtown_godverse top out at 2 shops within 160 m. Rather than drop the bias
        // entirely (which stranded venues at 0), fall back to the DENSEST available: the venue still
        // lands on what little crowd the town has. Only fires where the floor is unreachable, so no
        // already-pinned town moves.
        let best = 0; for (const s of pool) { const n = clusterCount(s); if (n > best) best = n; }
        if (best > 0) field = pool.filter(s => clusterCount(s) >= best);
      }
    }

    let cand;
    if (kind === 'band_room') {
      cand = field.filter(s => blockKindOf(s) === 'warehouse');
      if (!cand.length) cand = field.filter(s => !onMain(s));           // osm: no warehouse district
    } else if (kind === 'rsl') {
      cand = field.filter(s => !onMain(s) && blockKindOf(s) !== 'warehouse');
      if (!cand.length) cand = field.filter(s => !onMain(s));
    } else {
      cand = field.filter(onMain);
      // a SECOND pub belongs at the other end of the spine, not next door to the first
      const firstPub = out.find(v => v.kind === 'pub');
      if (firstPub) {
        const pz = (lotOf(firstPub.shop) || {}).z || 0;
        const far = cand.filter(s => Math.sign((lotOf(s) || {}).z || 0) !== Math.sign(pz));
        if (far.length) cand = far;
      }
    }
    // ROUND16 ledger #6 (widened ROUND20): keep a venue's frontage poster off a crossing street's bitumen.
    // Prefer candidates whose +Z facade clears every carriageway by ≥ POSTER_CLEAR; if the primary set has
    // none, broaden to any off-spine clear lot before falling back. R16 exempted `pub` because on the
    // synthetic/marched towns its +Z is always open — but on a REAL road graph at density the pub can land
    // where its facade overhangs a cross street (newtown, R20). The filter now covers every venue kind: on
    // the synthetic town every pub/rsl candidate already clears, so it stays a no-op there (golden frozen).
    {
      let clear = cand.filter(s => facadeClear(s) >= POSTER_CLEAR);
      if (!clear.length) clear = field.filter(s => !onMain(s) && facadeClear(s) >= POSTER_CLEAR); // stay in the cluster
      if (clear.length) cand = clear;
    }
    if (!cand.length) cand = field;                                      // last resort: anything cluster-adjacent
    if (!cand.length) cand = pool;                                       // truly degenerate: anything left
    const shortlist = farthestFirst(cand).slice(0, Math.min(5, cand.length));
    const shop = pick(rng(citySeed, 'venuepick', i), shortlist);
    if (!shop) break;
    taken.add(shop.id);
    out.push({ shop, kind });
  }
  return out;
}

// Convert a chosen shop into a venue of `kind`, in place.
function convertVenue(citySeed, shop, kind) {
  const reg = SHOP_TYPES[kind];
  const vseed = seedFor(citySeed, 'venue', shop.id);
  const vr = mulberry32(vseed);
  shop.type = kind;
  shop.facadeSkin = pick(vr, reg.facades);
  const nm = shopName(vseed, kind);
  shop.name = nm.name; shop.sign = nm.sign;
  // clamp into the kind's registry band (the shop may have been a 3-storey corner anchor; a band room
  // is a single-storey shed). A pub reads as a ≥2-storey corner hotel.
  shop.storeys = Math.min(Math.max(shop.storeys | 0, reg.storeys[0]), reg.storeys[1]);
  if (kind === 'pub') shop.storeys = Math.max(shop.storeys, 2);
  shop.hours = [reg.hours.open, reg.hours.close];  // open into NIGHT so the gig runs
  shop.venue = true;                               // easy lookup alongside venueKind
  shop.venueKind = kind;
  shop.genreKey = reg.genre;                       // ⇒ gigKeyFor(genreKey) is the audio bed
  return shop;
}

// ── the week's schedule ───────────────────────────────────────────────────────────────
// 7 nights × every venue, but not every venue plays every night: each takes a seeded 4–6 of the 7 and
// goes dark the rest. Slots are walked NIGHT-MAJOR so John's custom band names spread across the whole
// week rather than filling one venue's residency.
function buildSchedule(plan, citySeed, venues, customBands) {
  const playing = venues.map((v) => {
    const k = irange(rng(citySeed, 'gignights', v.shop.id), GIGS_PER_VENUE[0], GIGS_PER_VENUE[1]);
    const order = shuffle(rng(citySeed, 'gigwhich', v.shop.id), [0, 1, 2, 3, 4, 5, 6]);
    return new Set(order.slice(0, k));
  });

  // John's OPTIONAL custom names (web/assets/custom_bands.json via opts.customBands) get PRIORITY —
  // deduped, shuffled deterministically, filled first. Absent/empty ⇒ pure generator (?noassets path).
  const seen = new Set();
  const custom = (Array.isArray(customBands) ? customBands : [])
    .filter(b => typeof b === 'string' && b.trim())
    .map(b => b.trim())
    .filter(b => (seen.has(b) ? false : (seen.add(b), true)));
  const queue = custom.length ? shuffle(rng(citySeed, 'bands', 0), custom.slice()) : [];

  const gigs = [];
  const usedByNight = new Map();
  let ci = 0, gi = 0;

  for (let night = 0; night < NIGHTS; night++) {
    let used = usedByNight.get(night);
    if (!used) usedByNight.set(night, used = new Set());
    for (let vi = 0; vi < venues.length; vi++) {
      if (!playing[vi].has(night)) continue;                 // dark tonight
      const v = venues[vi];

      // No band plays two venues at once. Custom names are deduped and used at most once each, so they
      // can never clash; a GENERATED name can collide with anything already booked tonight, so advance
      // the generator stream until it doesn't (deterministic: `gi` only ever moves forward).
      let band;
      if (ci < queue.length) band = queue[ci++];
      else do { band = bandName(seedFor(citySeed, 'band', gi++)); } while (used.has(band));
      used.add(band);

      const cv = COVER_BY_KIND[v.kind] || COVER_BY_KIND.pub;
      const gr = mulberry32(seedFor(citySeed, 'gig', v.shop.id * 8 + night));
      const cover = gr() < cv.free ? 0 : cv.min + ((gr() * (cv.max - cv.min + 1)) | 0);

      gigs.push({
        gigId: gigs.length, venueShopId: v.shop.id, bandName: band, genreKey: v.shop.genreKey,
        night, startSeg: GIG_START_SEG, endSeg: GIG_END_SEG, cover,
      });
    }
  }
  return gigs;
}

// ── posters, town-wide ────────────────────────────────────────────────────────────────
// Each venue playing TONIGHT (night 0) gets a poster on its own frontage plus a seeded run along the
// spine. Different venues' posters share the same pole runs — that IS the district reading.
//
// `ry` follows the ONE house convention, the same one lot.ry uses and selfcheck enforces: it is the
// Y-rotation of a thing whose FRONT/outward normal is local −Z at ry=0, i.e. world facing
// (−sin ry, −cos ry). A poster faces the people who read it.
//
// ROUND13 debt #5 — R12 put spine posters at `node.x + 2`, i.e. 2m from an intersection's CENTRELINE,
// which is mid-bitumen on a 28m corridor. They now seat on the verge via registry.poleOffset(edge)
// (just behind the kerb), and the venue's own poster sits on its FACADE rather than at the lot centre,
// which is inside the building shell.
function buildPosters(plan, citySeed, venues, gigs) {
  const posters = [];
  const add = (x, z, ry, gigId) => posters.push({ id: posters.length, gigId, x: r2(x), z: r2(z), ry: r4(ry) });
  const lotById = new Map(plan.lots.map(l => [l.id, l]));
  const nodeById = new Map(plan.streets.nodes.map(n => [n.id, n]));

  const tonight = new Map();                       // venueShopId → tonight's gig
  for (const g of gigs) if (g.night === 0 && !tonight.has(g.venueShopId)) tonight.set(g.venueShopId, g);
  if (!tonight.size) return posters;               // every venue dark tonight — no posters, reads true

  // 1. one on each playing venue's own frontage
  for (const v of venues) {
    const gig = tonight.get(v.shop.id);
    const lot = gig && lotById.get(v.shop.lot);
    if (!lot) continue;
    // ROUND15 (ledger #1): B's buildings put the street facade on local +Z (frontage/queue seat on
    // (sin ry, cos ry)); this once used −Z, so the poster sat ~16 m BEHIND the building, invisible from
    // the street — it's why queue_night framed no poster. Seat it on the +Z street face, AND turn it to
    // read FROM the street: venue.js renders a poster's printed face along (−sin ry, −cos ry) = A's
    // outward normal, so ry = lot.ry + π points that face outward (else DoubleSide shows a mirrored name).
    const fx = Math.sin(lot.ry), fz = Math.cos(lot.ry);     // +Z: the street facade (B's canon)
    const off = lot.d / 2 + FACADE_PROUD;                   // out onto the facade plane, proud of it
    add(lot.x + fx * off, lot.z + fz * off, lot.ry + Math.PI, gig.gigId);
  }

  // 2. the spine run — seeded pole positions along main edges, on the verge, facing the footpath.
  const spine = plan.streets.edges.filter(e => e.kind === 'main');
  const runs = spine.length ? spine : plan.streets.edges.slice();
  const bill = [...tonight.values()];
  if (!runs.length || !bill.length) return posters;

  // ROUND19 (E's finding): on a REAL street graph a spine edge is crossed by side streets, so a pole
  // placed on the spine verge can overhang a crossing carriageway. Skip any candidate that lands on a
  // carriageway — measured EXACTLY as the selfcheck's floor (nearest edge, `roadWidth/2`). This is a
  // no-op on the synthetic town (its spine posters already clear every carriageway, so nothing skips and
  // the gig golden is frozen); it only drops the overhanging ones on real graphs. `pr()` is consumed
  // before the check, so the rng stream — hence the synthetic output — is unchanged.
  const onCarriageway = (x, z) => {
    let best = Infinity, bestE = null;
    for (const e2 of plan.streets.edges) {
      const a2 = nodeById.get(e2.a), b2 = nodeById.get(e2.b); if (!a2 || !b2) continue;
      const ex = b2.x - a2.x, ez = b2.z - a2.z, L2 = ex * ex + ez * ez || 1;
      let tt = ((x - a2.x) * ex + (z - a2.z) * ez) / L2; tt = Math.max(0, Math.min(1, tt));
      const d = Math.hypot(x - (a2.x + ex * tt), z - (a2.z + ez * tt));
      if (d < best) { best = d; bestE = e2; }
    }
    return bestE && best < roadWidth(bestE) / 2 - 1e-6;
  };
  const pr = rng(citySeed, 'posters', 0);
  const PER_EDGE = 2;
  const spineCands = [];
  for (const e of runs) {
    const a = nodeById.get(e.a), b = nodeById.get(e.b);
    if (!a || !b) continue;
    const dx = b.x - a.x, dz = b.z - a.z, len = Math.hypot(dx, dz);
    if (len < 8) continue;
    const ux = dx / len, uz = dz / len;
    const off = poleOffset(e);                     // verge, just behind the kerb — never bitumen
    for (let i = 0; i < PER_EDGE; i++) {
      const t = 0.2 + 0.6 * pr();                  // somewhere along the block, not on the corner
      const side = pr() < 0.5 ? 1 : -1;
      // outward normal (road → pole), exactly marchStrip's convention: a pole is a tiny lot, its front
      // faces back across its own footpath, so ry = atan2(nx, nz).
      const nx = side > 0 ? -uz : uz, nz = side > 0 ? ux : -ux;
      const x = a.x + ux * len * t + nx * off, z = a.z + uz * len * t + nz * off;
      if (onCarriageway(r2(x), r2(z))) continue;   // check the r2-rounded position `add` stores — overhangs a crossing → skip (E's R18 finding)
      spineCands.push({ x, z, ry: Math.atan2(nx, nz) });
    }
  }
  // ROUND20 poster cap: thin the pole run to ~POSTER_PER_SHOP × shops (a seeded subsample), so a sparse
  // real town reads like a main street, not a poster wall. cap ≫ candidates on synthetic ⇒ no-op ⇒ frozen.
  const cap = Math.max(POSTER_SPINE_FLOOR, Math.round(POSTER_PER_SHOP * plan.shops.length));
  const chosen = spineCands.length > cap ? shuffle(rng(citySeed, 'postercap', 0), spineCands.slice()).slice(0, cap) : spineCands;
  let k = 0;
  for (const c of chosen) add(c.x, c.z, c.ry, bill[k++ % bill.length].gigId);
  return posters;
}

// ── public: augment a finished plan with the gig layer ─────────────────────────────────
// Mutates + returns `plan` (caller passes a fresh plan). Adds `plan.gigs` + `plan.posters` and converts
// 2–4 shops into venues in place.
export function withGigs(plan, citySeed, opts = {}) {
  citySeed = citySeed >>> 0;
  const venues = pickVenues(plan, citySeed);
  if (!venues.length) { plan.gigs = []; plan.posters = []; return plan; }  // no plain shops at all

  for (const v of venues) convertVenue(citySeed, v.shop, v.kind);
  plan.gigs = buildSchedule(plan, citySeed, venues, opts.customBands);
  plan.posters = buildPosters(plan, citySeed, venues, plan.gigs);
  return plan;
}