import { BitByBitOCCT, OccStateEnum } from '@bitbybit-dev/occt-worker'
import type { Inputs } from '@bitbybit-dev/occt'
import type { ApplyPlacementInput, BooleanCutInput, BooleanIntersectionInput, BooleanUnionInput, CreateBoxInput, CreateConeInput, CreateCylinderInput, CreateSphereInput, GeometryCapabilities, GeometryDocumentContext, LinearFeatureParameters, MeshAsset, PadInput, PlanarProfile, PocketInput, Point3, RevolutionInput, ShapeHandle, SubshapeRef } from './types'
import { createSubshapeRefs } from './topologyNaming'

type KernelShapeReference = Inputs.OCCT.TopoDSShapePointer
type KernelMesh = Inputs.OCCT.DecomposedMeshDto
type ShapeEntry = { handle: ShapeHandle; reference: KernelShapeReference }
type KernelReferenceEntry = { count: number; reference: KernelShapeReference }

const unavailableCapabilities = (): GeometryCapabilities => ({
  provider: 'Bitbybit OCCT',
  version: '1.1.1',
  status: typeof Worker === 'undefined' ? 'unavailable' : 'idle',
  worker: typeof Worker !== 'undefined',
  wasm: typeof WebAssembly !== 'undefined',
  reason: typeof Worker === 'undefined' ? 'Web Workers are not available in this runtime.' : undefined,
})

const finitePositive = (value: number, name: string) => {
  if (!Number.isFinite(value) || value <= 0) throw new RangeError(`${name} must be a finite number greater than zero.`)
}

const finiteNonNegative = (value: number, name: string) => {
  if (!Number.isFinite(value) || value < 0) throw new RangeError(`${name} must be a finite non-negative number.`)
}

const validateDocumentContext = (input: GeometryDocumentContext) => {
  if (!input.documentId.trim()) throw new RangeError('documentId must be a non-empty string.')
  if (!Number.isSafeInteger(input.documentVersion) || input.documentVersion < 0) throw new RangeError('documentVersion must be a non-negative safe integer.')
}

const validateVector = (value: [number, number, number], name: string, allowZero = true) => {
  if (value.length !== 3 || value.some((coordinate) => !Number.isFinite(coordinate))) throw new RangeError(`${name} must contain three finite coordinates.`)
  if (!allowZero && value.every((coordinate) => coordinate === 0)) throw new RangeError(`${name} must not be the zero vector.`)
}

const validateAngle = (value: number, name: string, allowZero = false) => {
  if (!Number.isFinite(value) || value > 360 || value < (allowZero ? 0 : Number.EPSILON)) throw new RangeError(`${name} must be between ${allowZero ? '0' : '0 (exclusive)'} and 360 degrees.`)
}

export const validateBoxInput = (input: CreateBoxInput) => {
  finitePositive(input.width, 'width')
  finitePositive(input.length, 'length')
  finitePositive(input.height, 'height')
  validateDocumentContext(input)
  const center = input.center ?? [0, 0, 0]
  validateVector(center, 'center')
}

export const validateCylinderInput = (input: CreateCylinderInput) => {
  finitePositive(input.radius, 'radius')
  finitePositive(input.height, 'height')
  validateVector(input.center ?? [0, 0, 0], 'center')
  validateVector(input.direction ?? [0, 1, 0], 'direction', false)
  validateAngle(input.angle ?? 360, 'angle')
  validateDocumentContext(input)
}

export const validateSphereInput = (input: CreateSphereInput) => {
  finitePositive(input.radius, 'radius')
  validateVector(input.center ?? [0, 0, 0], 'center')
  validateDocumentContext(input)
}

export const validateConeInput = (input: CreateConeInput) => {
  finiteNonNegative(input.radius1, 'radius1')
  finiteNonNegative(input.radius2, 'radius2')
  if (input.radius1 === 0 && input.radius2 === 0) throw new RangeError('At least one cone radius must be greater than zero.')
  finitePositive(input.height, 'height')
  validateVector(input.center ?? [0, 0, 0], 'center')
  validateVector(input.direction ?? [0, 1, 0], 'direction', false)
  validateAngle(input.angle ?? 360, 'angle')
  validateDocumentContext(input)
}

export const validatePlacementInput = (input: ApplyPlacementInput) => {
  validateVector(input.placement.translation, 'translation')
  validateVector(input.placement.rotationAxis, 'rotationAxis', false)
  validateAngle(input.placement.rotationAngle, 'rotationAngle', true)
  validateDocumentContext(input)
  validateShapeContext(input, input.shape)
}

const validateShapeContext = (input: GeometryDocumentContext, shape: ShapeHandle) => {
  if (shape.documentId !== input.documentId) throw new Error(`Shape belongs to another document: ${shape.id}`)
  if (shape.documentVersion > input.documentVersion) throw new Error(`Shape version is newer than the result context: ${shape.id}`)
}

const validateBooleanShapes = (input: GeometryDocumentContext, shapes: ShapeHandle[], minimum: number) => {
  validateDocumentContext(input)
  if (shapes.length < minimum) throw new RangeError(`Boolean operation requires at least ${minimum} shape${minimum === 1 ? '' : 's'}.`)
  for (const shape of shapes) validateShapeContext(input, shape)
}

export const validateBooleanUnionInput = (input: BooleanUnionInput) => validateBooleanShapes(input, input.shapes, 2)

export const validateBooleanCutInput = (input: BooleanCutInput) => {
  validateBooleanShapes(input, [input.base, ...input.tools], 2)
  if (input.tools.length === 0) throw new RangeError('Boolean cut requires at least one tool shape.')
}

export const validateBooleanIntersectionInput = (input: BooleanIntersectionInput) => validateBooleanShapes(input, input.shapes, 2)

const samePoint = (left: Point3, right: Point3, tolerance = 1e-9) => left.every((coordinate, axis) => Math.abs(coordinate - right[axis]) <= tolerance)
const subtract = (left: Point3, right: Point3): Point3 => [left[0] - right[0], left[1] - right[1], left[2] - right[2]]
const cross = (left: Point3, right: Point3): Point3 => [left[1] * right[2] - left[2] * right[1], left[2] * right[0] - left[0] * right[2], left[0] * right[1] - left[1] * right[0]]
const dot = (left: Point3, right: Point3) => left[0] * right[0] + left[1] * right[1] + left[2] * right[2]
const magnitude = (value: Point3) => Math.hypot(value[0], value[1], value[2])

const normalizedRing = (ring: Point3[]) => ring.length > 1 && samePoint(ring[0], ring.at(-1) as Point3) ? ring.slice(0, -1) : [...ring]

const ringNormal = (ring: Point3[]): Point3 | null => {
  const origin = ring[0]
  for (let index = 1; index < ring.length - 1; index += 1) {
    const candidate = cross(subtract(ring[index], origin), subtract(ring[index + 1], origin))
    if (magnitude(candidate) > 1e-9) return candidate
  }
  return null
}

export const validatePlanarProfile = (profile: PlanarProfile) => {
  const rings = [normalizedRing(profile.outer), ...(profile.holes ?? []).map(normalizedRing)]
  for (const [ringIndex, ring] of rings.entries()) {
    if (ring.length < 3) throw new RangeError(`Profile ring ${ringIndex} requires at least three distinct points.`)
    ring.forEach((point, pointIndex) => {
      validateVector(point, `profile ring ${ringIndex} point ${pointIndex}`)
      if (samePoint(point, ring[(pointIndex + 1) % ring.length])) throw new RangeError(`Profile ring ${ringIndex} contains consecutive duplicate points.`)
    })
  }
  const origin = rings[0][0]
  const normal = ringNormal(rings[0])
  if (!normal) throw new RangeError('Profile ring 0 is collinear.')
  const normalLength = magnitude(normal)
  for (const [ringIndex, ring] of rings.entries()) {
    if (!ringNormal(ring)) throw new RangeError(`Profile ring ${ringIndex} is collinear.`)
    for (const point of ring) if (Math.abs(dot(normal, subtract(point, origin))) / normalLength > 1e-7) throw new RangeError(`Profile ring ${ringIndex} is not coplanar with the outer ring.`)
  }
}

const validateLinearFeature = (input: GeometryDocumentContext & LinearFeatureParameters) => {
  validateDocumentContext(input)
  validatePlanarProfile(input.profile)
  finitePositive(input.length, 'length')
  validateVector(input.direction ?? [0, 1, 0], 'direction', false)
}

export const validatePadInput = (input: PadInput) => validateLinearFeature(input)

export const validatePocketInput = (input: PocketInput) => {
  validateLinearFeature(input)
  validateShapeContext(input, input.base)
}

export const validateRevolutionInput = (input: RevolutionInput) => {
  validateDocumentContext(input)
  validatePlanarProfile(input.profile)
  validateVector(input.axisOrigin ?? [0, 0, 0], 'axisOrigin')
  validateVector(input.axisDirection ?? [0, 1, 0], 'axisDirection', false)
  validateAngle(input.angle ?? 360, 'angle')
}

export const assertShapeHandleIntegrity = (actual: ShapeHandle, expected: ShapeHandle) => {
  if (actual.id !== expected.id || actual.kernel !== expected.kernel || actual.kind !== expected.kind || actual.documentId !== expected.documentId || actual.documentVersion !== expected.documentVersion) throw new Error(`Shape handle integrity check failed: ${actual.id}`)
}

const appendFace = (face: Inputs.OCCT.DecomposedFaceDto, positions: number[], normals: number[], indices: number[]) => {
  if (face.vertexCoord.length % 3 !== 0 || face.triIndexes.length % 3 !== 0) throw new Error(`Bitbybit OCCT returned malformed arrays for face ${face.faceIndex}.`)
  if (face.vertexCoord.some((coordinate) => !Number.isFinite(coordinate)) || face.normalCoord.some((coordinate) => !Number.isFinite(coordinate))) throw new Error(`Bitbybit OCCT returned non-finite coordinates for face ${face.faceIndex}.`)
  if (face.normalCoord.length !== 0 && face.normalCoord.length !== face.vertexCoord.length) throw new Error(`Bitbybit OCCT returned mismatched normals for face ${face.faceIndex}.`)
  const faceVertexCount = face.vertexCoord.length / 3
  if (face.triIndexes.some((index) => !Number.isSafeInteger(index) || index < 0 || index >= faceVertexCount)) throw new Error(`Bitbybit OCCT returned an out-of-range triangle index for face ${face.faceIndex}.`)
  const vertexOffset = positions.length / 3
  positions.push(...face.vertexCoord)
  if (face.normalCoord.length === face.vertexCoord.length) normals.push(...face.normalCoord)
  else for (let index = 0; index < face.vertexCoord.length; index += 3) normals.push(0, 0, 0)
  for (const index of face.triIndexes) indices.push(vertexOffset + index)
}

export const normalizeBitbybitMesh = (shape: ShapeHandle, mesh: KernelMesh, tolerance = 1e-5): MeshAsset => {
  const positions: number[] = []
  const normals: number[] = []
  const indices: number[] = []
  mesh.faceList.forEach((face) => appendFace(face, positions, normals, indices))
  if (positions.length === 0 || indices.length === 0) throw new Error('Bitbybit OCCT returned an empty mesh for the shape.')

  const min: [number, number, number] = [Infinity, Infinity, Infinity]
  const max: [number, number, number] = [-Infinity, -Infinity, -Infinity]
  for (let index = 0; index < positions.length; index += 3) {
    for (let axis = 0; axis < 3; axis += 1) {
      min[axis] = Math.min(min[axis], positions[index + axis])
      max[axis] = Math.max(max[axis], positions[index + axis])
    }
  }
  const subshapes: SubshapeRef[] = createSubshapeRefs(shape.id, shape.documentVersion, mesh.faceList.map((face) => ({ vertexCoord: face.vertexCoord, normalCoord: face.normalCoord, triIndexes: face.triIndexes })), tolerance).refs
  return {
    shapeId: shape.id,
    topologyVersion: shape.documentVersion,
    positions: new Float32Array(positions),
    normals: new Float32Array(normals),
    indices: new Uint32Array(indices),
    subshapes,
    bounds: { min, max },
  }
}

export class BitbybitGeometryRuntime {
  private capabilitiesState = unavailableCapabilities()
  private client: BitByBitOCCT | null = null
  private worker: Worker | null = null
  private initialization: Promise<GeometryCapabilities> | null = null
  private cancelInitialization: (() => void) | null = null
  private sequence = 0
  private readonly shapes = new Map<string, ShapeEntry>()
  private readonly kernelReferences = new Map<number, KernelReferenceEntry>()

  capabilities(): GeometryCapabilities { return { ...this.capabilitiesState } }

  initialize(): Promise<GeometryCapabilities> {
    if (this.capabilitiesState.status === 'ready') return Promise.resolve(this.capabilities())
    if (this.initialization) return this.initialization
    if (typeof Worker === 'undefined' || typeof WebAssembly === 'undefined') {
      this.capabilitiesState = { ...unavailableCapabilities(), status: 'unavailable', reason: 'WebAssembly and Web Workers are required for Bitbybit OCCT.' }
      return Promise.resolve(this.capabilities())
    }

    this.capabilitiesState = { ...this.capabilitiesState, status: 'initializing', reason: undefined }
    this.initialization = new Promise<GeometryCapabilities>((resolve, reject) => {
      let settled = false
      const client = new BitByBitOCCT()
      const worker = new Worker(new URL('./geometryWorker.ts', import.meta.url), { type: 'module', name: 'bitbybit-occt' })
      this.client = client
      this.worker = worker
      const timeout = window.setTimeout(() => fail(new Error('Bitbybit OCCT initialization timed out.')), 120_000)
      const subscription = client.occtWorkerManager.occWorkerState$.subscribe(({ state }) => {
        if (state !== OccStateEnum.initialised || settled) return
        settled = true
        window.clearTimeout(timeout)
        subscription.unsubscribe()
        this.cancelInitialization = null
        this.capabilitiesState = { ...this.capabilitiesState, status: 'ready', worker: true, wasm: true }
        resolve(this.capabilities())
      })
      const fail = (error: Error) => {
        const wasSettled = settled
        settled = true
        window.clearTimeout(timeout)
        subscription.unsubscribe()
        worker.terminate()
        this.shapes.clear()
        this.kernelReferences.clear()
        this.worker = null
        this.client = null
        this.initialization = null
        this.cancelInitialization = null
        this.capabilitiesState = { ...this.capabilitiesState, status: 'failed', reason: error.message }
        if (!wasSettled) reject(error)
      }
      this.cancelInitialization = () => fail(new Error('Bitbybit OCCT initialization was cancelled.'))
      worker.addEventListener('error', (event) => fail(new Error(event.message || 'Bitbybit OCCT worker failed.')), { once: true })
      worker.addEventListener('message', ({ data }) => {
        if (data?.type === 'occ-initialization-failed') fail(new Error(data.error || 'Bitbybit OCCT initialization failed.'))
      })
      client.occtWorkerManager.errorCallback = (error) => { this.capabilitiesState = { ...this.capabilitiesState, reason: error } }
      client.init(worker)
    })
    return this.initialization
  }

  async createBox(input: CreateBoxInput): Promise<ShapeHandle> {
    validateBoxInput(input)
    const client = await this.readyClient()
    const kernelShape = await client.occt.shapes.solid.createBox({
      width: input.width,
      length: input.length,
      height: input.height,
      center: input.center ?? [0, 0, 0],
      originOnCenter: input.originOnCenter ?? true,
    })
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async createCylinder(input: CreateCylinderInput): Promise<ShapeHandle> {
    validateCylinderInput(input)
    const client = await this.readyClient()
    const kernelShape = await client.occt.shapes.solid.createCylinder({
      radius: input.radius,
      height: input.height,
      center: input.center ?? [0, 0, 0],
      direction: input.direction ?? [0, 1, 0],
      angle: input.angle ?? 360,
      originOnCenter: input.originOnCenter ?? false,
    })
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async createSphere(input: CreateSphereInput): Promise<ShapeHandle> {
    validateSphereInput(input)
    const client = await this.readyClient()
    const kernelShape = await client.occt.shapes.solid.createSphere({ radius: input.radius, center: input.center ?? [0, 0, 0] })
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async createCone(input: CreateConeInput): Promise<ShapeHandle> {
    validateConeInput(input)
    const client = await this.readyClient()
    const kernelShape = await client.occt.shapes.solid.createCone({
      radius1: input.radius1,
      radius2: input.radius2,
      height: input.height,
      angle: input.angle ?? 360,
      center: input.center ?? [0, 0, 0],
      direction: input.direction ?? [0, 1, 0],
    })
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async applyPlacement(input: ApplyPlacementInput): Promise<ShapeHandle> {
    validatePlacementInput(input)
    const source = this.resolveShape(input.shape)
    const client = await this.readyClient()
    const kernelShape = await client.occt.transforms.transform({
      shape: source.reference,
      translation: input.placement.translation,
      rotationAxis: input.placement.rotationAxis,
      rotationAngle: input.placement.rotationAngle,
      scaleFactor: 1,
    })
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async union(input: BooleanUnionInput): Promise<ShapeHandle> {
    validateBooleanUnionInput(input)
    const shapes = input.shapes.map((shape) => this.resolveShape(shape).reference)
    const client = await this.readyClient()
    const kernelShape = await client.occt.booleans.union({ shapes, keepEdges: input.keepEdges ?? false })
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async cut(input: BooleanCutInput): Promise<ShapeHandle> {
    validateBooleanCutInput(input)
    const base = this.resolveShape(input.base).reference
    const tools = input.tools.map((shape) => this.resolveShape(shape).reference)
    const client = await this.readyClient()
    const kernelShape = await client.occt.booleans.difference({ shape: base, shapes: tools, keepEdges: input.keepEdges ?? false })
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async intersection(input: BooleanIntersectionInput): Promise<ShapeHandle> {
    validateBooleanIntersectionInput(input)
    const shapes = input.shapes.map((shape) => this.resolveShape(shape).reference)
    const client = await this.readyClient()
    const kernelShape = await client.occtWorkerManager.genericCallToWorkerPromise('plugins.boolean.intersection', { shapes, keepEdges: input.keepEdges ?? false }) as KernelShapeReference
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async pad(input: PadInput): Promise<ShapeHandle> {
    validatePadInput(input)
    const client = await this.readyClient()
    const kernelShape = await this.createExtrusion(client, input)
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async pocket(input: PocketInput): Promise<ShapeHandle> {
    validatePocketInput(input)
    const base = this.resolveShape(input.base).reference
    const client = await this.readyClient()
    const tool = await this.createExtrusion(client, input)
    const kernelShape = await client.occt.booleans.difference({ shape: base, shapes: [tool], keepEdges: false })
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async revolution(input: RevolutionInput): Promise<ShapeHandle> {
    validateRevolutionInput(input)
    const client = await this.readyClient()
    const face = await this.createProfileFace(client, input.profile)
    const kernelShape = await client.occtWorkerManager.genericCallToWorkerPromise('plugins.feature.revolution', {
      shape: face,
      axisOrigin: input.axisOrigin ?? [0, 0, 0],
      axisDirection: input.axisDirection ?? [0, 1, 0],
      angle: input.angle ?? 360,
    }) as KernelShapeReference
    return this.registerShape(kernelShape, input.documentId, input.documentVersion)
  }

  async mesh(shape: ShapeHandle, precision = 0.05): Promise<MeshAsset> {
    finitePositive(precision, 'precision')
    const entry = this.resolveShape(shape)
    const client = await this.readyClient()
    const mesh = await client.occt.shapeToMesh({ shape: entry.reference, precision, adjustYtoZ: false })
    return normalizeBitbybitMesh(entry.handle, mesh, Math.max(1e-5, precision * 0.1))
  }

  async subshapes(shape: ShapeHandle, precision = 0.05): Promise<SubshapeRef[]> {
    return (await this.mesh(shape, precision)).subshapes ?? []
  }

  async release(shape: ShapeHandle): Promise<void> {
    const entry = this.shapes.get(shape.id)
    if (!entry) return
    this.assertHandle(shape, entry.handle)
    this.shapes.delete(shape.id)
    const kernelReference = this.kernelReferences.get(entry.reference.hash)
    if (kernelReference && kernelReference.count > 1) {
      kernelReference.count -= 1
      return
    }
    this.kernelReferences.delete(entry.reference.hash)
    const client = this.client
    if (client && this.capabilitiesState.status === 'ready' && this.shapes.size === 0) await client.occt.cleanAllCache()
  }

  dispose() {
    this.cancelInitialization?.()
    this.shapes.clear()
    this.kernelReferences.clear()
    this.client?.occtWorkerManager.cleanPromisesMade()
    this.worker?.terminate()
    this.client = null
    this.worker = null
    this.initialization = null
    this.cancelInitialization = null
    this.capabilitiesState = unavailableCapabilities()
  }

  private async readyClient() {
    const capabilities = await this.initialize()
    if (capabilities.status !== 'ready' || !this.client) throw new Error(capabilities.reason || 'Bitbybit OCCT is unavailable.')
    return this.client
  }

  private async createProfileFace(client: BitByBitOCCT, profile: PlanarProfile): Promise<KernelShapeReference> {
    const rings = [normalizedRing(profile.outer), ...(profile.holes ?? []).map(normalizedRing)]
    const outerNormal = ringNormal(rings[0]) as Point3
    const orientedRings = rings.map((ring, index) => index > 0 && dot(outerNormal, ringNormal(ring) as Point3) > 0 ? [...ring].reverse() : ring)
    const wires = await Promise.all(orientedRings.map((points) => client.occt.shapes.wire.createPolygonWire({ points })))
    return client.occt.shapes.face.createFaceFromWires({ shapes: wires, planar: true })
  }

  private async createExtrusion(client: BitByBitOCCT, input: LinearFeatureParameters): Promise<KernelShapeReference> {
    const direction = input.direction ?? [0, 1, 0]
    const directionLength = magnitude(direction)
    const sign = input.reversed ? -1 : 1
    const extrusion: Point3 = direction.map((coordinate) => coordinate / directionLength * input.length * sign) as Point3
    let face = await this.createProfileFace(client, input.profile)
    if (input.symmetricToPlane) {
      const translation = extrusion.map((coordinate) => -coordinate / 2) as Point3
      face = await client.occt.transforms.translate({ shape: face, translation })
    }
    return client.occt.operations.extrude({ shape: face, direction: extrusion })
  }

  private registerShape(reference: KernelShapeReference, documentId: string, documentVersion: number) {
    const handle: ShapeHandle = {
      id: `shape-${Date.now().toString(36)}-${(++this.sequence).toString(36)}`,
      kernel: 'bitbybit-occt',
      kind: 'solid',
      documentId,
      documentVersion,
    }
    const kernelReference = this.kernelReferences.get(reference.hash)
    if (kernelReference) kernelReference.count += 1
    else this.kernelReferences.set(reference.hash, { count: 1, reference })
    this.shapes.set(handle.id, { handle, reference })
    return handle
  }

  private resolveShape(shape: ShapeHandle) {
    if (shape.kernel !== 'bitbybit-occt') throw new Error(`Unsupported geometry kernel: ${shape.kernel}`)
    const entry = this.shapes.get(shape.id)
    if (!entry) throw new Error(`Shape handle is unknown or has been released: ${shape.id}`)
    this.assertHandle(shape, entry.handle)
    return entry
  }

  private assertHandle(actual: ShapeHandle, expected: ShapeHandle) {
    assertShapeHandleIntegrity(actual, expected)
  }
}