import React, { useEffect, useRef, useState } from 'react'
import { useThree, useFrame } from 'react-three-fiber'
import {
  Geometry,
  Event,
  Group,
  PerspectiveCamera,
  Vector3,
  Raycaster,
  Mesh,
  CircleGeometry,
} from 'three'
import WorldCollisions from './models/WorldCollisions'

import useStore from '../store'
import { MeshBasicMaterial } from 'three/src/materials/MeshBasicMaterial'

const SPEED = 1
const HEIGHT = 1.5
const CIRCLE_RADIUS = 1.0
const CIRCLE_SEGMENTS = 8

const keys: Record<string, string> = {
  KeyW: 'forward',
  KeyS: 'backward',
  KeyA: 'left',
  KeyD: 'right',
  ArrowUp: 'forward',
  ArrowDown: 'backward',
  ArrowLeft: 'left',
  ArrowRight: 'right',
  ShiftLeft: 'run',
  Space: 'jump',
}
const moveFieldByKey = (key: string) => keys[key]

function FirstPersonCamera(props: JSX.IntrinsicElements['perspectiveCamera']) {
  const ref = useRef<PerspectiveCamera>()
  const { setDefaultCamera } = useThree()
  // Make the camera known to the system
  useEffect(() => {
    if (ref.current) setDefaultCamera(ref.current)
  }, [ref.current])
  // Update it every frame
  useFrame(() => ref.current?.updateMatrixWorld())
  return <perspectiveCamera ref={ref} {...props} />
}

const usePlayerControls = () => {
  const [movement, setMovement] = useState({
    forward: false,
    backward: false,
    left: false,
    right: false,
    run: false,
    jump: false,
  })
  useEffect(() => {
    const handleKeyDown = (e: Event) => {
      setMovement((m) => ({ ...m, [moveFieldByKey(e.code)]: true }))
    }
    const handleKeyUp = (e: Event) => {
      setMovement((m) => ({ ...m, [moveFieldByKey(e.code)]: false }))
    }
    document.addEventListener('keydown', handleKeyDown)
    document.addEventListener('keyup', handleKeyUp)
    return () => {
      document.removeEventListener('keydown', handleKeyDown)
      document.removeEventListener('keyup', handleKeyUp)
    }
  }, [])
  return movement
}

// TODO Improve physics in player
const Player = () => {
  const socket = useStore((state) => state.socket)
  const pointerLocked = useStore((state) => state.pointerLocked)
  const { forward, backward, left, right, run } = usePlayerControls()
  const { camera } = useThree()

  const groupRef = useRef<Group>()
  const collisionsRef = useRef<Mesh<CircleGeometry, MeshBasicMaterial>>(null)
  const velocity = useRef<Vector3>(new Vector3())
  const direction = useRef<Vector3>(new Vector3())
  const worldOrigin = useRef<Vector3>(new Vector3())
  const currentPositionClone = useRef<Vector3>(new Vector3())

  const bottomRaycaster = useRef(
    new Raycaster(new Vector3(), new Vector3(0, -1, 0), 0, HEIGHT + 0.5),
  )

  const collisionCircle = useRef<Mesh>()
  const collisionCircleGeometry = new CircleGeometry(CIRCLE_RADIUS, CIRCLE_SEGMENTS)
  collisionCircleGeometry.rotateX(Math.PI / 2)
  const collisionCircleMaterial = new MeshBasicMaterial({
    color: 0xff0000,
    wireframe: true,
  })

  const wallRaycasters = useRef<Raycaster[]>(
    Array(CIRCLE_SEGMENTS)
      .fill(undefined)
      .map((_, i) => {
        const vert = collisionCircleGeometry.vertices[i + 1].clone()
        const direction = vert.sub(collisionCircleGeometry.vertices[0]).normalize()

        return new Raycaster(new Vector3(), direction, 0, CIRCLE_RADIUS)
      }),
  )

  useEffect(() => {
    const socketEmitTransformInterval = setInterval(() => {
      if (socket && groupRef.current && camera) {
        const cameraRotation = camera.rotation.toArray()
        socket.emit('transform', {
          position: [
            groupRef.current?.position.x,
            groupRef.current?.position.y,
            groupRef.current?.position.z,
          ],
          rotation: [cameraRotation[0], cameraRotation[1], cameraRotation[2]],
        })
      }
    }, 50)

    return () => {
      clearInterval(socketEmitTransformInterval)
    }
  }, [])

  const moveForward = (distance: number) => {
    if (groupRef.current) {
      worldOrigin.current.setFromMatrixColumn(camera.matrix, 0)
      worldOrigin.current.crossVectors(camera.up, worldOrigin.current)
      groupRef.current.position.addScaledVector(worldOrigin.current, distance)
    }
  }

  const moveRight = (distance: number) => {
    if (groupRef.current) {
      worldOrigin.current.setFromMatrixColumn(camera.matrix, 0)
      groupRef.current.position.addScaledVector(worldOrigin.current, distance)
    }
  }

  useFrame((_, delta) => {
    if (!groupRef.current || !collisionsRef.current || !collisionCircle.current) return

    if (pointerLocked) {
      // Slowdown
      velocity.current.x -= velocity.current.x * 10.0 * delta
      velocity.current.z -= velocity.current.z * 10.0 * delta

      // Fall
      bottomRaycaster.current.ray.origin.copy(groupRef.current.position)

      let intersections = []
      intersections = bottomRaycaster.current.intersectObject(
        collisionsRef.current,
        false,
      )

      if (intersections.length < 1) {
        velocity.current.y -= 9.8 * 10 * delta
      } else {
        velocity.current.y = 0
        groupRef.current.position.y = intersections[0].point.y + HEIGHT
      }

      // Direction
      direction.current.z = Number(forward) - Number(backward)
      direction.current.x = Number(left) - Number(right)
      direction.current.normalize()

      // Running
      const speed = run ? 1.5 : 1

      // Move
      if (forward || backward)
        velocity.current.z -= direction.current.z * SPEED * delta * speed
      if (left || right) velocity.current.x -= direction.current.x * SPEED * delta * speed

      // Wall collisions
      const collisionCircleGeometry = collisionCircle.current.geometry as Geometry

      if (collisionCircleGeometry.vertices) {
        for (let i = 0; i < CIRCLE_SEGMENTS; i++) {
          wallRaycasters.current[i].ray.origin.copy(groupRef.current.position)

          let wallIntersections = []
          wallIntersections = wallRaycasters.current[i].intersectObject(
            collisionsRef.current,
            false,
          )

          if (
            wallIntersections.length > 0 &&
            wallIntersections[0].distance < CIRCLE_RADIUS
          ) {
            const distance = CIRCLE_RADIUS - wallIntersections[0].distance

            currentPositionClone.current.copy(groupRef.current.position)
            const direction = wallIntersections[0].point
              .sub(currentPositionClone.current)
              .normalize()
              .multiplyScalar(distance)

            groupRef.current.position.sub(direction)
          }
        }
      }

      // Apply speed
      moveForward(-velocity.current.x * speed)
      moveRight(-velocity.current.z * speed)
      groupRef.current.position.y += velocity.current.y * delta
    }

    // TODO enable jump if cheating
    //if (jump && Math.abs(parseFloat(velocity.current[1].toFixed(2))) < 0.05)
    //  api.velocity.set(velocity.current[0], 10, velocity.current[2])
  })
  return (
    <>
      <group ref={groupRef} position={[0, 5, 0]} rotation={[0, -Math.PI / 2, 0]}>
        <FirstPersonCamera rotation={[0, Math.PI / 2, 0]} />
        <mesh
          ref={collisionCircle}
          position={[0, -HEIGHT / 2, 0]}
          geometry={collisionCircleGeometry}
          material={collisionCircleMaterial}
          visible={false}
        />
      </group>
      <WorldCollisions ref={collisionsRef} visible={false} />
    </>
  )
}

export default Player
