/**
 * INTEGRATION SEAM — owned by integration, not by lanes.
 * The playable slice: a blob + paint + buffs, the shared race loop, and a
 * COURSE. The flagship "Breakfast Rush" is hand-built (buildBreakfastRush — it
 * carries a lot of integration tuning); extra courses are data (see course/spec)
 * and load with `?course=<name>`.
 */
import * as THREE from 'three'
import type { World } from './contracts'
import { buildGreybox } from './course/greybox'
import { createBlob, type BlobHandle } from './blob/createBlob'
import { createBlobController } from './blob/controller'
import { createBlobFeel } from './blob/feel'
import { createFollowCamera } from './blob/camera'
import { PaintSkin, PaintCannon, BuffSystem, PaintHUD, installPaint } from './paint/index'
import {
  createBucketDump, createBubbleArch, createConveyorBelt, createPaintMine, createColorGate,
  createPaintBubbles, SURFACES, applySurface,
} from './machine/index'
import { installZones } from './course/zones'
import { buildCourseFromSpec, COURSES, COURSE_META, type FinishBox } from './course/spec'
import { installCheckpoints, type CheckpointList } from './course/checkpoints'
import { assets } from './assets/registry'
import { hasOverrides } from './assets/idb'
import { installAudio } from './audio/index'
import { installGhost } from './ghost/index'
import { installTitle } from './ui/title'

/** Breakfast Rush spawn — matches buildGreybox()'s recommended spawn plateau. */
const BREAKFAST_SPAWN = new THREE.Vector3(0, 3.5, 30)

/** Breakfast Rush checkpoints: landing shelf, slope bottom, fork entrance.
 *  y is the local floor top at that spot (posts stand on it; respawn is +0.8). */
const BREAKFAST_CHECKPOINTS: CheckpointList = [
  // Two, both on dry open ground. No mid-course one: the slope's volume would
  // eject a respawner and the river's rinse strips the paint a checkpoint is
  // supposed to preserve — a fall there honestly costs you the river re-run.
  [0, 3.5, -6],   // gap-jump landing shelf
  [0, 0.24, -42], // machine district / fork entrance
]

/**
 * Build the hand-tuned flagship course onto the world and return its finish box.
 * (Everything here used to live inline in installGame; it is course-specific.)
 */
function buildBreakfastRush(world: World, blob: BlobHandle, skin: PaintSkin): FinishBox {
  buildGreybox(world)

  // ---- paint economy (Lane G): puddles + colour zones + MEGA/MINI fork ----
  const zones = installZones(world, blob, skin)
  for (const spec of zones.cannonConfigs) {
    world.addSystem(new PaintCannon({
      world,
      position: new THREE.Vector3(...spec.position),
      color: spec.color,
      target: blob.mesh,
      paint: skin,
      targetRadius: blob.radius,
      triggerId: spec.triggerId,
      interval: spec.interval,
      muzzleSpeed: 26, // default 16 caps ballistic range at ~18u — course distances need ~26
      splatRadius: 0.45,
    }))
  }

  // ---- centre-lane machine garnish (Lane C) ----
  // The fork owns plate/boot now (zones.ts). The belt+bucket moved to the
  // CENTRE lane: un-forked runners get slow-carried under a purple dump —
  // a free taste of MEGA with no roof above (never dump grow-juice inside
  // the MINI tunnel: growing under the roof would wedge you).
  createBucketDump(world, {
    id: 'bucket-1', position: [-1.4, 6, -50],
    color: 'purple', radius: 0.8,
    // Shallow catch just upstream of the spout (bucket.x+1.4 = belt centre x=0):
    // observed teeter drift is 0.4-2u depending on speed.
    trigger: { size: [3, 2, 1.6], offset: [1.4, -5.2, 0.75] },
  })
  createConveyorBelt(world, {
    id: 'belt-1', position: [0, 0.0, -50], // sunk flush with the machine pad — a proud belt face curbed the racing line
    size: [3, 0.5, 10], velocity: [0, 0, -3],
  })
  createBubbleArch(world, {
    id: 'arch-1', position: [-4.5, 0.12, -56], fraction: 0.6, // purple-lane exit: cleansing punishes a failed MEGA attempt
  })

  // ---- paint bubbles: blue soap bubbles drifting over the milk-river approach.
  // Pop one mid-run → SLICK/waterproof → your paint survives the rinse. The
  // bubble colour teaches the counter to the hazard it floats above. ----
  createPaintBubbles(world, {
    id: 'bubbles-river', position: [0, 1.4, -24], color: 'blue', radius: 0.6,
    splats: 2, count: 6, area: [5, 1.0, 2.5], drift: [0, 0.3, 0], bubbleRadius: 0.6,
  })

  // ---- paint-mines: first-through floor panels on the centre line ----
  // REWARD: roll over it and it launches you forward + coats you GREEN (GRIP) —
  // a shortcut booster for the runner who takes the middle. HAZARD: further down,
  // dumps heavy PURPLE (MEGA) and shoves you toward the pink tunnel lane where a
  // grown blob bonks the roof — the greedy straight-liner pays for it. Both
  // re-arm each run (race:respawn) so the time-trial stays repeatable.
  createPaintMine(world, {
    id: 'mine-reward', position: [0, 0.06, -34], color: 'green', radius: 0.9, splats: 5,
    impulse: 8, direction: [0, 1, -0.6], size: [3.4, 3.4],
  })
  createPaintMine(world, {
    id: 'mine-hazard', position: [0, 0.24, -44], color: 'purple', radius: 0.8, splats: 4,
    impulse: 7, direction: [0.8, 0.5, 0], size: [3, 3],
  })

  // ---- oil slick: a slippery patch on the flat approach. applySurface gives
  // it oil friction with a Min combine rule, so it stays slick under ANY blob
  // (even a grippy green one), and the userData tag lets the controller throttle
  // steering + add drag → you luge across it. Demo of the surface framework. ----
  {
    const oilMat = new THREE.MeshStandardMaterial({
      color: SURFACES.oil.color, roughness: 0.12, metalness: 0.35,
    })
    const oil = new THREE.Mesh(new THREE.BoxGeometry(6, 0.08, 4), oilMat)
    oil.position.set(0, 0.28, -40) // machine-pad centre lane (top y0.24), clear of the fork exits + hazard mine
    oil.receiveShadow = true
    world.scene.add(oil)
    const oilCol = world.physics.createCollider(
      world.rapier.ColliderDesc.cuboid(3, 0.04, 2).setTranslation(0, 0.28, -40))
    applySurface(world.rapier, oilCol, 'oil')
    ;(oilCol as unknown as { userData?: unknown }).userData = { surface: 'oil' }
  }

  // ---- colour-keyed gate: a GREEN shortcut through the centre lane, just
  // before the finish. Roll over the green reward mine upstream and you arrive
  // green enough for the gate to sink into the floor — a straight blast to the
  // line. Arrive un-green and it stays shut, so you steer around the short
  // flank walls (a detour). Closes the core loop solo: paint decides your route.
  // Walls only cover the centre (|x|<4) so the fork exits (boot x-6, tunnel
  // x6.5) are untouched. ----
  {
    const gz = -59
    const wallMat = new THREE.MeshStandardMaterial({ color: '#5b6b7a', roughness: 0.85 })
    for (const x of [-3, 3] as const) { // flank the centre gate gap (gate is x[-2,2])
      const wall = new THREE.Mesh(new THREE.BoxGeometry(2, 3, 0.8), wallMat)
      wall.position.set(x, 1.5, gz)
      wall.castShadow = true
      wall.receiveShadow = true
      world.scene.add(wall)
      world.physics.createCollider(
        world.rapier.ColliderDesc.cuboid(1, 1.5, 0.4).setTranslation(x, 1.5, gz))
    }
    createColorGate(world, {
      id: 'gate-green', position: [0, 0.02, gz], color: 'green', size: [4, 3, 0.6],
      qualifies: () => skin.coverage().byColor.green >= 0.4,
    })
  }

  // ---- gap-recovery trampoline: falling in the gap jump must cost time, not
  // soft-lock you under the green slope (straight-line drivers wedged at z≈-16.6).
  // A deterministic launcher bounces fallers back to shelf height. ----
  {
    const tramp = new THREE.Mesh(
      new THREE.BoxGeometry(12, 0.5, 4),
      new THREE.MeshStandardMaterial({ color: '#FF9500', roughness: 0.6 }))
    tramp.position.set(0, 0.25, 0) // exactly the open slot between the shelves
    tramp.receiveShadow = true
    world.scene.add(tramp)
    world.physics.createCollider(
      world.rapier.ColliderDesc.cuboid(6, 0.25, 2).setTranslation(0, 0.25, 0))
    // course.tramp slot: hide the MATERIAL, not the mesh — the custom model is
    // parented as a child, so hiding the mesh would hide it too. The collider
    // above is untouched, so the bounce is identical whatever the pad looks like.
    assets().attachSlot('course.tramp', tramp, {
      onSwap: () => { (tramp.material as THREE.Material).visible = false },
    })
    // Fill BOTH under-shelf volumes solid: the front-face plinth stopped
    // overshooters, but lane-huggers rolled in from the open x±7 sides and
    // wedged (observed at (-4.1,-7.9)). Under-shelf space serves no gameplay —
    // make the shelves read as solid blocks down to the floor.
    const plinthMat = new THREE.MeshStandardMaterial({ color: '#0A5FCB', roughness: 0.8 })
    // Central fill only (x±5.2): observed wedges are all |x|<4.5; full-width
    // fills walled off the floor-level side corridors lane-hug routes use.
    for (const [zc, hz] of [[6, 4], [-6, 4]] as const) {
      const fill = new THREE.Mesh(new THREE.BoxGeometry(10.4, 2.8, hz * 2), plinthMat)
      fill.position.set(0, 1.4, zc)
      world.scene.add(fill)
      world.physics.createCollider(
        world.rapier.ColliderDesc.cuboid(5.2, 1.4, hz).setTranslation(0, 1.4, zc))
    }
    // Deterministic launcher, not restitution: raw bounciness pachinkos off the
    // shelf's front edge and can still slip underneath. Catch a falling blob on
    // the pad and set a clean arc onto the landing shelf.
    let bounceCooldown = 0
    world.addSystem({
      update(dt) {
        bounceCooldown = Math.max(0, bounceCooldown - dt)
        const t = blob.body.translation()
        const v = blob.body.linvel()
        const onPad = Math.abs(t.x) < 7.2 && t.z > -2.2 && t.z < 2.2 && t.y < 1.4 // full gap width — lane-huggers fall at |x|≈7
        if (onPad && v.y < 0.5 && bounceCooldown === 0) {
          // High + centered: held-W air control (~24 u/s²) flattens shallow arcs
          // into the shelf face, so go UP hard and pull toward the slot center;
          // forward drift only wins after the arc clears the shelf top.
          const vz = Math.max(-3, Math.min(3, (0.5 - t.z) * 1.5))
          const vx = Math.max(-3, Math.min(3, (0 - t.x) * 1.5)) // center x too — cannon impacts drift racers sideways
          blob.body.setLinvel({ x: vx, y: 14, z: vz }, true)
          bounceCooldown = 0.6
          world.events.emit('blob:jumped', {}) // reuse the stretch feel
        }
      },
    })
  }

  // Finish pad volume, extended to z -57.2 so a blob bonking the pad's front
  // face (a 1.2-high podium, unclimbable from the floor) still counts as a
  // finish. Mid-air crossings count too — the boot is a legit finisher.
  return { xMin: -9, xMax: 9, zMin: -70, zMax: -57.2, yMax: 4 }
}

export function installGame(world: World) {
  // ---- course selection: default = hand-built Breakfast Rush; ?course=<name>
  // loads a data-driven course from COURSES. Spawn is known before geometry. ----
  const which = new URLSearchParams(location.search).get('course')
  const spec = which ? COURSES[which] : undefined
  const spawn = spec ? new THREE.Vector3(...spec.spawn) : BREAKFAST_SPAWN.clone()

  // ---- blob (Lane A) ----
  const blob = createBlob(world, { position: spawn })
  blob.paint = new PaintSkin(blob.mesh, { size: 256 })
  world.blob = blob

  world.addSystem(createBlobController(world, blob))

  const feel = createBlobFeel(blob)
  world.events.on('blob:jumped', () => feel.onJump())
  world.events.on('blob:landed', (p: { impact: number }) => feel.onLand(p.impact))
  world.onFrame((dt) => feel.update(dt))

  const camera = createFollowCamera(world, blob)
  world.onFrame((dt) => camera.update(dt))

  const skin = blob.paint as PaintSkin

  // ---- build the selected course, get its finish box ----
  const finish = spec
    ? buildCourseFromSpec(world, spec, { blob, skin }).finish
    : buildBreakfastRush(world, blob, skin)

  // ---- checkpoints: a fall costs time, not the run (see course/checkpoints) ----
  const cps = installCheckpoints(world, blob, spec ? spec.checkpoints ?? [] : BREAKFAST_CHECKPOINTS)

  world.addSystem(new BuffSystem(world, { mesh: blob.mesh, modifiers: blob.modifiers, paint: skin }))
  installPaint(world, { mesh: blob.mesh, paint: skin })

  const hud = new PaintHUD()
  world.onFrame(() => {
    hud.update(skin.coverage(), blob.modifiers) // coverage() self-caches at 250ms
  })

  // ---- race loop: first movement starts the clock, the finish box ends it ----
  // Per-course best time so switching courses doesn't compare apples to oranges.
  const bestKey = `blobbo:best${spec ? ':' + which : ''}`
  let raceState: 'idle' | 'running' | 'finished' = 'idle'
  let raceT = 0
  let best: number | null = Number(localStorage.getItem(bestKey)) || null

  const raceUI = document.createElement('div')
  raceUI.style.cssText =
    'position:fixed;top:12px;right:14px;font:700 20px ui-monospace,Menlo,monospace;' +
    'color:#0a2540;background:rgba(255,255,255,.82);padding:8px 14px;border-radius:10px;' +
    'z-index:15;text-align:right;pointer-events:none'
  document.body.appendChild(raceUI)
  const banner = document.createElement('div')
  banner.style.cssText =
    'position:fixed;inset:0;display:none;align-items:center;justify-content:center;' +
    'flex-direction:column;gap:12px;font:800 42px ui-monospace,Menlo,monospace;color:#fff;' +
    'background:rgba(20,24,34,.72);z-index:30;text-align:center'
  document.body.appendChild(banner)
  const fmt = (s: number) => s.toFixed(2) + 's'

  let finishHold = 0
  world.addSystem({
    update(dt) {
      const t = blob.body.translation()
      const v = blob.body.linvel()
      if (raceState === 'idle') {
        if (Math.hypot(v.x, v.z) > 0.6) {
          raceState = 'running'
          raceT = 0
          world.events.emit('race:started', {})
        }
      } else if (raceState === 'running') {
        raceT += dt
        const inFinish =
          t.x >= finish.xMin && t.x <= finish.xMax &&
          t.z >= finish.zMin && t.z <= finish.zMax && t.y <= finish.yMax
        if (inFinish) {
          raceState = 'finished'
          const isBest = best === null || raceT < best
          if (isBest) {
            best = raceT
            localStorage.setItem(bestKey, String(raceT))
          }
          banner.innerHTML =
            `<div>🏁 FINISH — ${fmt(raceT)}</div>` +
            `<div style="font-size:22px">${isBest ? 'NEW BEST!' : 'best ' + fmt(best!)}</div>` +
            `<div style="font-size:16px;opacity:.85">R / Start to race again — auto in 6s</div>`
          banner.style.display = 'flex'
          world.events.emit('race:finished', { time: raceT, best })
          finishHold = 6
        }
      } else {
        finishHold -= dt
        if (finishHold <= 0) respawn()
      }
      raceUI.textContent =
        (raceState === 'running' ? '⏱ ' + fmt(raceT) : raceState === 'idle' ? '⏱ ready' : '🏁 ' + fmt(raceT)) +
        (best !== null ? '  ·  best ' + fmt(best) : '')
    },
  })

  // ---- fall respawn + debug ----
  const respawn = () => {
    blob.body.setTranslation({ x: spawn.x, y: spawn.y, z: spawn.z }, true)
    blob.body.setLinvel({ x: 0, y: 0, z: 0 }, true)
    world.events.emit('paint:request-cleanse', { fraction: 1 })
    raceState = 'idle'
    raceT = 0
    banner.style.display = 'none'
    world.events.emit('race:respawn', {})
  }
  // Fixed-step, not onFrame: the fall check GATES gameplay, and onFrame stalls
  // in hidden tabs (same lesson as telegraph/bucket — found at integration).
  world.addSystem({
    update() {
      if (blob.body.translation().y < -25) {
        // Mid-run with a checkpoint lit → soft respawn there: clock keeps running
        // (the fall's cost is time) and paint stays (progress already earned).
        // Otherwise it's a full restart to the line.
        const cp = raceState === 'running' ? cps.last() : null
        if (cp) {
          blob.body.setTranslation({ x: cp.x, y: cp.y + 0.8, z: cp.z }, true)
          blob.body.setLinvel({ x: 0, y: 0, z: 0 }, true)
        } else {
          respawn()
        }
      }
    },
  })
  addEventListener('keydown', (e) => {
    if (e.code === 'KeyR') respawn()
    if (e.code === 'KeyC') world.events.emit('paint:request-cleanse', { fraction: 0.5 })
  })

  // ---- gamepad niceties (movement/jump live in the blob controller) ----
  let startHeld = false
  world.addSystem({
    update() {
      const pads = navigator.getGamepads?.()
      if (!pads) return
      for (const p of pads) {
        if (!p || !p.connected) continue
        const s = !!p.buttons[9]?.pressed // Start/Options = respawn
        if (s && !startHeld) respawn()
        startHeld = s
        break
      }
    },
  })
  addEventListener('gamepadconnected', (e) => {
    const toast = document.createElement('div')
    toast.textContent = `🎮 ${(e as GamepadEvent).gamepad.id.slice(0, 40)} connected — stick to roll, A to jump, Start to respawn`
    toast.style.cssText =
      'position:fixed;bottom:16px;left:50%;transform:translateX(-50%);' +
      'font:13px ui-monospace,Menlo,monospace;color:#fff;background:rgba(20,24,34,.88);' +
      'padding:9px 14px;border-radius:9px;z-index:20;pointer-events:none'
    document.body.appendChild(toast)
    setTimeout(() => toast.remove(), 3200)
  })

  // ---- course switcher: cycles through COURSE_META's rotation (shared with
  // the title's course select). Labs/unknown courses cycle home. ----
  {
    const i = COURSE_META.findIndex((c) => c.course === (which ?? undefined))
    const other = COURSE_META[(i + 1) % COURSE_META.length] ?? COURSE_META[0]
    const link = document.createElement('a')
    link.href = other.href
    link.textContent = `▸ course: ${other.emoji} ${other.label}`
    link.style.cssText =
      'position:fixed;top:56px;right:14px;font:12px ui-monospace,Menlo,monospace;' +
      'color:#0a2540;background:rgba(255,255,255,.82);padding:6px 11px;border-radius:9px;' +
      'text-decoration:none;z-index:15;box-shadow:0 1px 6px rgba(0,0,0,.14)'
    document.body.appendChild(link)
  }

  // ---- custom-assets pill: a forgotten Workshop swap otherwise reads as a
  // broken game ("why is the boot a weird cylinder?"), with no way back. ----
  void hasOverrides().then((on) => {
    if (!on) return
    const pill = document.createElement('a')
    pill.href = 'editor.html'
    pill.textContent = '🎨 your custom models are on — open the Workshop'
    pill.style.cssText =
      'position:fixed;bottom:14px;left:14px;font:12px ui-monospace,Menlo,monospace;' +
      'color:#0a2540;background:rgba(255,255,255,.86);padding:7px 12px;border-radius:999px;' +
      'text-decoration:none;z-index:18;box-shadow:0 1px 6px rgba(0,0,0,.18)'
    document.body.appendChild(pill)
  })

  // ---- wave 2: audio, ghost, title ----
  installAudio(world)
  installGhost(world, blob, { radius: blob.radius, course: which ?? undefined })
  installTitle(world)

  // debug handle (dev builds are the only builds right now)
  ;(window as unknown as { BLOBBO: unknown }).BLOBBO = { world, blob, skin, spawn, finish }

  return { blob, spawn, finish }
}