import {
  DroppableContainer,
  KeyboardCode,
  KeyboardCoordinateGetter,
  closestCorners,
  getFirstCollision,
} from "@dnd-kit/core"

import type { SensorContext } from "./types"
import { getProjection } from "./utils"

const directions: string[] = [
  KeyboardCode.Down,
  KeyboardCode.Right,
  KeyboardCode.Up,
  KeyboardCode.Left,
]

const horizontal: string[] = [KeyboardCode.Left, KeyboardCode.Right]

export const sortableTreeKeyboardCoordinates: (
  context: SensorContext,
  indentationWidth: number
) => KeyboardCoordinateGetter =
  (context, indentationWidth) =>
  (
    event,
    {
      currentCoordinates,
      context: {
        active,
        over,
        collisionRect,
        droppableRects,
        droppableContainers,
      },
    }
  ) => {
    if (directions.includes(event.code)) {
      if (!active || !collisionRect) {
        return
      }

      event.preventDefault()

      const {
        current: { items, offset },
      } = context

      if (horizontal.includes(event.code) && over?.id) {
        const { depth, maxDepth, minDepth } = getProjection(
          items,
          active.id,
          over.id,
          offset,
          indentationWidth
        )

        switch (event.code) {
          case KeyboardCode.Left:
            if (depth > minDepth) {
              return {
                ...currentCoordinates,
                x: currentCoordinates.x - indentationWidth,
              }
            }
            break
          case KeyboardCode.Right:
            if (depth < maxDepth) {
              return {
                ...currentCoordinates,
                x: currentCoordinates.x + indentationWidth,
              }
            }
            break
        }

        return undefined
      }

      const containers: DroppableContainer[] = []

      droppableContainers.forEach((container) => {
        if (container?.disabled || container.id === over?.id) {
          return
        }

        const rect = droppableRects.get(container.id)

        if (!rect) {
          return
        }

        switch (event.code) {
          case KeyboardCode.Down:
            if (collisionRect.top < rect.top) {
              containers.push(container)
            }
            break
          case KeyboardCode.Up:
            if (collisionRect.top > rect.top) {
              containers.push(container)
            }
            break
        }
      })

      const collisions = closestCorners({
        active,
        collisionRect,
        pointerCoordinates: null,
        droppableRects,
        droppableContainers: containers,
      })
      let closestId = getFirstCollision(collisions, "id")

      if (closestId === over?.id && collisions.length > 1) {
        closestId = collisions[1].id
      }

      if (closestId && over?.id) {
        const activeRect = droppableRects.get(active.id)
        const newRect = droppableRects.get(closestId)
        const newDroppable = droppableContainers.get(closestId)

        if (activeRect && newRect && newDroppable) {
          const newIndex = items.findIndex(({ id }) => id === closestId)
          const newItem = items[newIndex]
          const activeIndex = items.findIndex(({ id }) => id === active.id)
          const activeItem = items[activeIndex]

          if (newItem && activeItem) {
            const { depth } = getProjection(
              items,
              active.id,
              closestId,
              (newItem.depth - activeItem.depth) * indentationWidth,
              indentationWidth
            )
            const isBelow = newIndex > activeIndex
            const modifier = isBelow ? 1 : -1
            const offset = 0

            const newCoordinates = {
              x: newRect.left + depth * indentationWidth,
              y: newRect.top + modifier * offset,
            }

            return newCoordinates
          }
        }
      }
    }

    return undefined
  }