'use client'

import {
  type AnyNodeId,
  emitter,
  type GridEvent,
  pauseSceneHistory,
  resumeSceneHistory,
  useScene,
  type WallNode,
} from '@pascal-app/core'
import { useViewer } from '@pascal-app/viewer'
import { Html } from '@react-three/drei'
import { useCallback, useEffect, useRef, useState } from 'react'
import { markToolCancelConsumed } from '../../../hooks/use-keyboard'
import { sfxEmitter } from '../../../lib/sfx-bus'
import useEditor, { type MovingWallEndpoint } from '../../../store/use-editor'
import { CursorSphere } from '../shared/cursor-sphere'
import {
  formatAngleRadians,
  getAngleToSegmentReference,
  getSegmentAngleReferenceAtPoint,
} from '../shared/segment-angle'
import { isWallLongEnough, snapWallDraftPoint, type WallPlanPoint } from './wall-drafting'

function samePoint(a: WallPlanPoint, b: WallPlanPoint) {
  return a[0] === b[0] && a[1] === b[1]
}

type WallSegmentLike = {
  id: WallNode['id']
  start: WallPlanPoint
  end: WallPlanPoint
  curveOffset?: number
}

type AngleLabelState = {
  label: string
  position: [number, number, number]
} | null

function getEndpointAngleLabel(args: {
  preview: { start: WallPlanPoint; end: WallPlanPoint; curveOffset?: number }
  walls: WallSegmentLike[]
  nodeId: WallNode['id']
}): AngleLabelState {
  const { preview, walls, nodeId } = args
  const endpoints = [
    {
      point: preview.start,
    },
    {
      point: preview.end,
    },
  ]
  const targetSegment: WallSegmentLike = {
    id: nodeId,
    start: preview.start,
    end: preview.end,
    curveOffset: preview.curveOffset,
  }

  for (const endpoint of endpoints) {
    const targetReference = getSegmentAngleReferenceAtPoint(endpoint.point, targetSegment)
    if (!targetReference) continue

    const connectedWall = walls.find(
      (wall) =>
        wall.id !== nodeId && Boolean(getSegmentAngleReferenceAtPoint(endpoint.point, wall)),
    )
    if (!connectedWall) continue

    const connectedReference = getSegmentAngleReferenceAtPoint(endpoint.point, connectedWall)
    if (!connectedReference) continue

    const angle = getAngleToSegmentReference(targetReference.vector, connectedReference)
    if (angle === null) continue

    return {
      label: formatAngleRadians(angle),
      position: [endpoint.point[0], 0.34, endpoint.point[1]],
    }
  }

  return null
}

type LinkedWallSnapshot = {
  id: WallNode['id']
  start: WallPlanPoint
  end: WallPlanPoint
  curveOffset?: number
}

function getLinkedWallSnapshots(args: {
  wallId: WallNode['id']
  wallParentId: string | null
  originalStart: WallPlanPoint
  originalEnd: WallPlanPoint
}) {
  const { wallId, wallParentId, originalStart, originalEnd } = args
  const { nodes } = useScene.getState()
  const snapshots: LinkedWallSnapshot[] = []

  for (const node of Object.values(nodes)) {
    if (!(node?.type === 'wall' && node.id !== wallId)) {
      continue
    }

    if ((node.parentId ?? null) !== wallParentId) {
      continue
    }

    if (
      !(
        samePoint(node.start, originalStart) ||
        samePoint(node.start, originalEnd) ||
        samePoint(node.end, originalStart) ||
        samePoint(node.end, originalEnd)
      )
    ) {
      continue
    }

    snapshots.push({
      id: node.id,
      start: [...node.start] as WallPlanPoint,
      end: [...node.end] as WallPlanPoint,
      curveOffset: node.curveOffset,
    })
  }

  return snapshots
}

function getLinkedWallUpdates(
  linkedWalls: LinkedWallSnapshot[],
  originalStart: WallPlanPoint,
  originalEnd: WallPlanPoint,
  nextStart: WallPlanPoint,
  nextEnd: WallPlanPoint,
) {
  return linkedWalls.map((wall) => ({
    id: wall.id,
    curveOffset: wall.curveOffset,
    start: samePoint(wall.start, originalStart)
      ? nextStart
      : samePoint(wall.start, originalEnd)
        ? nextEnd
        : wall.start,
    end: samePoint(wall.end, originalStart)
      ? nextStart
      : samePoint(wall.end, originalEnd)
        ? nextEnd
        : wall.end,
  }))
}

export const MoveWallEndpointTool: React.FC<{ target: MovingWallEndpoint }> = ({ target }) => {
  const activatedAtRef = useRef<number>(Date.now())
  const previousGridPosRef = useRef<WallPlanPoint | null>(null)
  const shiftPressedRef = useRef(false)
  const altPressedRef = useRef(false)
  const nodeIdRef = useRef(target.wall.id)
  const originalStartRef = useRef<WallPlanPoint>([...target.wall.start] as WallPlanPoint)
  const originalEndRef = useRef<WallPlanPoint>([...target.wall.end] as WallPlanPoint)
  const fixedPointRef = useRef<WallPlanPoint>(
    target.endpoint === 'start'
      ? ([...target.wall.end] as WallPlanPoint)
      : ([...target.wall.start] as WallPlanPoint),
  )
  const linkedOriginalsRef = useRef(
    getLinkedWallSnapshots({
      wallId: target.wall.id,
      wallParentId: target.wall.parentId ?? null,
      originalStart: target.wall.start,
      originalEnd: target.wall.end,
    }),
  )
  const previewRef = useRef<{ start: WallPlanPoint; end: WallPlanPoint } | null>(null)
  const [angleLabel, setAngleLabel] = useState<AngleLabelState>(null)

  const [cursorLocalPos, setCursorLocalPos] = useState<[number, number, number]>(() => {
    const point = target.endpoint === 'start' ? target.wall.start : target.wall.end
    return [point[0], 0, point[1]]
  })
  const [altPressed, setAltPressed] = useState(false)

  const exitMoveMode = useCallback(() => {
    useEditor.getState().setMovingWallEndpoint(null)
  }, [])

  useEffect(() => {
    const nodeId = nodeIdRef.current
    const originalStart = originalStartRef.current
    const originalEnd = originalEndRef.current
    const fixedPoint = fixedPointRef.current
    const levelWalls = Object.values(useScene.getState().nodes).filter(
      (node): node is WallNode =>
        node?.type === 'wall' && (node.parentId ?? null) === (target.wall.parentId ?? null),
    )

    pauseSceneHistory(useScene)
    let wasCommitted = false

    const applyNodePreview = (
      updates: Array<{ id: WallNode['id']; start: WallPlanPoint; end: WallPlanPoint }>,
    ) => {
      useScene.getState().updateNodes(
        updates.map((entry) => ({
          id: entry.id as AnyNodeId,
          data: { start: entry.start, end: entry.end },
        })),
      )
      for (const entry of updates) {
        useScene.getState().markDirty(entry.id as AnyNodeId)
      }
    }

    const applyPreview = (movingPoint: WallPlanPoint, detachLinkedWalls = false) => {
      const nextStart = target.endpoint === 'start' ? movingPoint : fixedPoint
      const nextEnd = target.endpoint === 'end' ? movingPoint : fixedPoint
      const linkedUpdates = detachLinkedWalls
        ? []
        : getLinkedWallUpdates(
            linkedOriginalsRef.current,
            originalStart,
            originalEnd,
            nextStart,
            nextEnd,
          )
      previewRef.current = { start: nextStart, end: nextEnd }
      setCursorLocalPos([movingPoint[0], 0, movingPoint[1]])
      setAngleLabel(
        getEndpointAngleLabel({
          preview: { start: nextStart, end: nextEnd, curveOffset: target.wall.curveOffset },
          walls: [
            ...levelWalls.map((wall) => ({
              id: wall.id,
              start: wall.start,
              end: wall.end,
              curveOffset: wall.curveOffset,
            })),
            ...linkedUpdates,
          ],
          nodeId,
        }),
      )
      applyNodePreview([{ id: nodeId, start: nextStart, end: nextEnd }, ...linkedUpdates])
    }

    const restoreOriginal = (clearAngleLabel = true) => {
      applyNodePreview([
        { id: nodeId, start: originalStart, end: originalEnd },
        ...linkedOriginalsRef.current,
      ])
      if (clearAngleLabel) {
        setAngleLabel(null)
      }
    }

    const onGridMove = (event: GridEvent) => {
      const planPoint: WallPlanPoint = [event.localPosition[0], event.localPosition[2]]
      const snappedPoint = snapWallDraftPoint({
        point: planPoint,
        walls: levelWalls,
        start: fixedPoint,
        angleSnap: !shiftPressedRef.current,
        ignoreWallIds: [nodeId],
      })

      if (
        previousGridPosRef.current &&
        (snappedPoint[0] !== previousGridPosRef.current[0] ||
          snappedPoint[1] !== previousGridPosRef.current[1])
      ) {
        sfxEmitter.emit('sfx:grid-snap')
      }
      previousGridPosRef.current = snappedPoint

      applyPreview(snappedPoint, event.nativeEvent.altKey)
    }

    const onGridClick = (event: GridEvent) => {
      if (Date.now() - activatedAtRef.current < 150) {
        event.nativeEvent?.stopPropagation?.()
        return
      }

      const preview = previewRef.current ?? { start: originalStart, end: originalEnd }
      const hasChanged = !(
        samePoint(preview.start, originalStart) && samePoint(preview.end, originalEnd)
      )

      if (hasChanged && isWallLongEnough(preview.start, preview.end)) {
        wasCommitted = true

        // Restore original baseline while paused so the next resume+update
        // registers as a single tracked change (undo reverts to original).
        applyNodePreview([
          { id: nodeId, start: originalStart, end: originalEnd },
          ...linkedOriginalsRef.current,
        ])

        resumeSceneHistory(useScene)
        applyNodePreview([
          { id: nodeId, start: preview.start, end: preview.end },
          ...(altPressedRef.current
            ? []
            : getLinkedWallUpdates(
                linkedOriginalsRef.current,
                originalStart,
                originalEnd,
                preview.start,
                preview.end,
              )),
        ])
        pauseSceneHistory(useScene)
        sfxEmitter.emit('sfx:item-place')
      }

      useViewer.getState().setSelection({ selectedIds: [nodeId] })
      setAngleLabel(null)
      exitMoveMode()
      event.nativeEvent?.stopPropagation?.()
    }

    const onCancel = () => {
      restoreOriginal()
      useViewer.getState().setSelection({ selectedIds: [nodeId] })
      resumeSceneHistory(useScene)
      setAngleLabel(null)
      markToolCancelConsumed()
      exitMoveMode()
    }

    const onKeyDown = (event: KeyboardEvent) => {
      if (event.target instanceof HTMLInputElement || event.target instanceof HTMLTextAreaElement) {
        return
      }
      if (event.key === 'Shift') {
        shiftPressedRef.current = true
      }
      if (event.key === 'Alt') {
        altPressedRef.current = true
        setAltPressed(true)
      }
    }

    const onKeyUp = (event: KeyboardEvent) => {
      if (event.key === 'Shift') {
        shiftPressedRef.current = false
      }
      if (event.key === 'Alt') {
        altPressedRef.current = false
        setAltPressed(false)
      }
    }

    const onWindowBlur = () => {
      shiftPressedRef.current = false
      altPressedRef.current = false
      setAltPressed(false)
    }

    emitter.on('grid:move', onGridMove)
    emitter.on('grid:click', onGridClick)
    emitter.on('tool:cancel', onCancel)
    window.addEventListener('keydown', onKeyDown)
    window.addEventListener('keyup', onKeyUp)
    window.addEventListener('blur', onWindowBlur)

    return () => {
      if (!wasCommitted) {
        restoreOriginal(false)
      }
      resumeSceneHistory(useScene)
      emitter.off('grid:move', onGridMove)
      emitter.off('grid:click', onGridClick)
      emitter.off('tool:cancel', onCancel)
      window.removeEventListener('keydown', onKeyDown)
      window.removeEventListener('keyup', onKeyUp)
      window.removeEventListener('blur', onWindowBlur)
    }
  }, [exitMoveMode, target])

  return (
    <group>
      <CursorSphere position={cursorLocalPos} showTooltip={false} />
      <Html
        position={[cursorLocalPos[0], 0, cursorLocalPos[2]]}
        style={{ pointerEvents: 'none', touchAction: 'none' }}
        zIndexRange={[100, 0]}
      >
        <div className="translate-y-10">
          <div
            className={`whitespace-nowrap rounded-full border px-2 py-1 font-medium text-[11px] shadow-lg backdrop-blur-md transition-colors ${
              altPressed
                ? 'border-amber-500/80 bg-amber-500/15 text-amber-100'
                : 'border-border bg-background/95 text-muted-foreground'
            }`}
          >
            {altPressed ? 'Detaching corner' : 'Alt to detach'}
          </div>
        </div>
      </Html>
      {angleLabel && <EndpointAngleLabel label={angleLabel.label} position={angleLabel.position} />}
    </group>
  )
}

function EndpointAngleLabel({
  label,
  position,
}: {
  label: string
  position: [number, number, number]
}) {
  return (
    <Html center position={position} style={{ pointerEvents: 'none' }} zIndexRange={[100, 0]}>
      <div className="whitespace-nowrap rounded-full border border-border bg-background/95 px-2 py-1 font-mono font-semibold text-[11px] text-foreground shadow-lg backdrop-blur-md">
        {label}
      </div>
    </Html>
  )
}