import {
  emitter,
  type GridEvent,
  ItemNode,
  sceneRegistry,
  useScene,
  useSpatialQuery,
  type WallEvent,
  type WallNode,
} from '@pascal-app/core'
import { useViewer } from '@pascal-app/viewer'
import { useFrame } from '@react-three/fiber'
import { useEffect, useRef } from 'react'
import { BoxGeometry, type Mesh, type MeshStandardMaterial, Vector3 } from 'three'
import useEditor from '@/store/use-editor'
import { resolveLevelId } from '../../../../../packages/core/src/hooks/spatial-grid/spatial-grid-sync'

/**
 * Snaps a position to 0.5 grid, with an offset to align item edges to grid lines.
 * For items with dimensions like 2.5, the center would be at 1.25 from the edge,
 * which doesn't align with 0.5 grid. This adds an offset so edges align instead.
 */
function snapToGrid(position: number, dimension: number): number {
  // Check if half the dimension has a 0.25 remainder (odd multiple of 0.5)
  const halfDim = dimension / 2
  const needsOffset = Math.abs(((halfDim * 2) % 1) - 0.5) < 0.01
  const offset = needsOffset ? 0.25 : 0
  // Snap to 0.5 grid with offset
  return Math.round((position - offset) * 2) / 2 + offset
}

export const ItemTool: React.FC = () => {
  const cursorRef = useRef<Mesh>(null!)
  const draftItem = useRef<ItemNode | null>(null)
  const gridPosition = useRef(new Vector3(0, 0, 0))
  const selectedItem = useEditor((state) => state.selectedItem)
  const { canPlaceOnFloor, canPlaceOnWall } = useSpatialQuery()
  const isOnWall = useRef(false)

  useEffect(() => {
    if (!selectedItem) {
      return
    }

    let currentWallId: string | null = null

    const checkCanPlace = () => {
      const currentLevelId = useViewer.getState().selection.levelId
      if (currentLevelId && draftItem.current) {
        let placeable = true
        if (draftItem.current.asset.attachTo) {
          if (!isOnWall.current || !currentWallId) {
            placeable = false
          } else {
            const result = canPlaceOnWall(
              currentLevelId,
              currentWallId as WallNode['id'],
              gridPosition.current.x,
              gridPosition.current.y,
              draftItem.current.asset.dimensions,
              [draftItem.current.id],
            )
            placeable = result.valid
          }
        } else {
          placeable = canPlaceOnFloor(
            currentLevelId,
            [gridPosition.current.x, 0, gridPosition.current.z],
            draftItem.current.asset.dimensions,
            [0, 0, 0],
            [draftItem.current.id],
          ).valid
        }
        if (placeable) {
          ;(cursorRef.current.material as MeshStandardMaterial).color.set('green')
          return true
        } else {
          ;(cursorRef.current.material as MeshStandardMaterial).color.set('red')
          return false
        }
      }
    }
    const createDraftItem = () => {
      const currentLevelId = useViewer.getState().selection.levelId
      if (!currentLevelId) {
        return null
      }
      useScene.temporal.getState().pause()
      draftItem.current = ItemNode.parse({
        position: [gridPosition.current.x, gridPosition.current.y, gridPosition.current.z],
        name: selectedItem.name,
        asset: selectedItem,
      })
      useScene.getState().createNode(draftItem.current, currentLevelId)
      checkCanPlace()
    }
    createDraftItem()

    const onGridMove = (event: GridEvent) => {
      if (!cursorRef.current) return

      if (isOnWall.current) return

      const [dimX, , dimZ] = selectedItem.dimensions
      gridPosition.current.set(
        snapToGrid(event.position[0], dimX),
        0,
        snapToGrid(event.position[2], dimZ),
      )
      cursorRef.current.position.set(
        gridPosition.current.x,
        event.position[1],
        gridPosition.current.z,
      )
      checkCanPlace()
      if (draftItem.current) {
        draftItem.current.position = [gridPosition.current.x, 0, gridPosition.current.z]
      }
    }
    const onGridClick = (event: GridEvent) => {
      const currentLevelId = useViewer.getState().selection.levelId
      if (isOnWall.current) return

      if (!currentLevelId || !draftItem.current || !checkCanPlace()) return

      useScene.temporal.getState().resume()
      useScene.getState().updateNode(draftItem.current.id, {
        position: [gridPosition.current.x, 0, gridPosition.current.z],
      })
      draftItem.current = null

      useScene.temporal.getState().pause()
      createDraftItem()
    }

    const onWallEnter = (event: WallEvent) => {
      if (
        useViewer.getState().selection.levelId !==
        resolveLevelId(event.node, useScene.getState().nodes)
      ) {
        return
      }
      if (
        draftItem.current?.asset.attachTo === 'wall' ||
        draftItem.current?.asset.attachTo === 'wall-side'
      ) {
        event.stopPropagation()
        isOnWall.current = true
        currentWallId = event.node.id
        gridPosition.current.set(
          Math.round(event.localPosition[0] * 2) / 2,
          Math.round(event.localPosition[1] * 2) / 2,
          Math.round(event.localPosition[2] * 2) / 2,
        )
        draftItem.current.parentId = event.node.id
        useScene.getState().updateNode(draftItem.current.id, {
          position: [gridPosition.current.x, gridPosition.current.y, gridPosition.current.z],
          parentId: event.node.id,
        })
        checkCanPlace()
      }
    }

    const onWallLeave = (event: WallEvent) => {
      if (!isOnWall.current) return
      isOnWall.current = false
      currentWallId = null
      event.stopPropagation()
      if (!draftItem.current) return
      const currentLevelId = useViewer.getState().selection.levelId
      draftItem.current.parentId = currentLevelId
      useScene.getState().updateNode(draftItem.current.id, {
        position: [gridPosition.current.x, gridPosition.current.y, gridPosition.current.z],
        parentId: currentLevelId,
      })
      checkCanPlace()
    }

    const onWallClick = (event: WallEvent) => {
      event.stopPropagation()
      if (!isOnWall.current) return

      const currentLevelId = useViewer.getState().selection.levelId
      if (!currentLevelId || !draftItem.current || !checkCanPlace()) return

      useScene.temporal.getState().resume()
      useScene.getState().updateNode(draftItem.current.id, {
        position: [gridPosition.current.x, gridPosition.current.y, gridPosition.current.z],
        parentId: event.node.id,
      })
      useScene.getState().dirtyNodes.add(event.node.id)
      draftItem.current = null

      useScene.temporal.getState().pause()
      createDraftItem()
      checkCanPlace()
    }

    const onWallMove = (event: WallEvent) => {
      if (isOnWall.current === false) return
      event.stopPropagation()
      if (!draftItem.current) return
      gridPosition.current.set(
        Math.round(event.localPosition[0] * 2) / 2,
        Math.round(event.localPosition[1] * 2) / 2,
        Math.round(event.localPosition[2] * 2) / 2,
      )
      cursorRef.current.position.set(
        Math.round(event.position[0] * 2) / 2,
        Math.round(event.position[1] * 2) / 2,
        Math.round(event.position[2] * 2) / 2,
      )

      const {
        node: { start, end },
      } = event
      const dx = end[0] - start[0]
      const dz = end[1] - start[1]
      const { normal } = event
      const wallAngle = Math.atan2(dx, dz)

      cursorRef.current.rotation.y = wallAngle + Math.PI / 2
      const canPlace = checkCanPlace()
      if (draftItem.current && canPlace) {
        draftItem.current.position = [
          gridPosition.current.x,
          gridPosition.current.y,
          gridPosition.current.z,
        ]
        const draftItemMesh = sceneRegistry.nodes.get(draftItem.current.id)
        if (draftItemMesh) {
          draftItemMesh.position.copy(gridPosition.current)
        }

        useScene.getState().dirtyNodes.add(event.node.id)
      }
    }

    emitter.on('grid:move', onGridMove)
    emitter.on('grid:click', onGridClick)
    emitter.on('wall:enter', onWallEnter)
    emitter.on('wall:move', onWallMove)
    emitter.on('wall:click', onWallClick)
    emitter.on('wall:leave', onWallLeave)

    const setupBoundingBox = () => {
      const boxGeometry = new BoxGeometry(
        selectedItem.dimensions[0],
        selectedItem.dimensions[1],
        selectedItem.dimensions[2],
      )
      boxGeometry.translate(0, selectedItem.dimensions[1] / 2, 0)
      cursorRef.current.geometry = boxGeometry
    }
    setupBoundingBox()

    return () => {
      if (draftItem.current) {
        useScene.getState().deleteNode(draftItem.current.id)
      }
      useScene.temporal.getState().resume()
      emitter.off('grid:move', onGridMove)
      emitter.off('grid:click', onGridClick)
      emitter.off('wall:enter', onWallEnter)
      emitter.off('wall:leave', onWallLeave)
      emitter.off('wall:click', onWallClick)
      emitter.off('wall:move', onWallMove)
    }
  }, [selectedItem, canPlaceOnFloor, canPlaceOnWall])

  useFrame((_, delta) => {
    if (draftItem.current && !isOnWall.current) {
      const draftItemMesh = sceneRegistry.nodes.get(draftItem.current.id)
      if (draftItemMesh) {
        draftItemMesh.position.lerp(gridPosition.current, delta * 20)
      }
    }
  })

  return (
    <group>
      <mesh ref={cursorRef}>
        <boxGeometry args={[0.1, 0.1, 0.1]} />
        <meshStandardMaterial color="red" wireframe />
      </mesh>
    </group>
  )
}