import { useCallback, useState, type Dispatch, type SetStateAction } from 'react'

import type { VectorSelectionBBox } from '../types'
import { bboxToInputState, normalizeBboxFromCorners, parseBboxInput } from '../components/map/mapWorkspaceUtils'

/**
 * The state of drawing a rectangle on the map: whether a gesture is in
 * progress, which corner has been placed, and what is typed in the coordinate
 * fields.
 *
 * Deliberately only the interaction state. What happens *with* a finished
 * rectangle — retiring stale results, starting an analysis — belongs to the
 * workspace, which owns those. Injecting that here would make the hook depend
 * on values declared after it.
 */

export type BboxInputState = ReturnType<typeof bboxToInputState>

export interface MapRectangleSelection {
  /** A rectangle gesture is in progress. */
  drawing: boolean
  setDrawing: Dispatch<SetStateAction<boolean>>
  /** The first click of a two-click rectangle, if one has been placed. */
  firstCorner: [number, number] | null
  bboxInput: BboxInputState
  setBboxInput: Dispatch<SetStateAction<BboxInputState>>
  /** The rectangle currently in the coordinate fields, if it parses. */
  typedBbox: VectorSelectionBBox | null
  /**
   * Place a corner. Returns the finished rectangle on the second corner, and
   * ``null`` on the first — the caller only acts when a rectangle exists.
   */
  placeCorner: (coordinate: [number, number]) => VectorSelectionBBox | null
  /** Abandon a half-drawn rectangle and leave drawing mode. */
  reset: () => void
  /** Show a rectangle in the coordinate fields. */
  showBbox: (bbox: VectorSelectionBBox | null) => void
}

export function useMapRectangleSelection(initialBbox: VectorSelectionBBox | null): MapRectangleSelection {
  const [drawing, setDrawing] = useState(false)
  const [firstCorner, setFirstCorner] = useState<[number, number] | null>(null)
  const [bboxInput, setBboxInput] = useState<BboxInputState>(bboxToInputState(initialBbox))

  const placeCorner = useCallback(
    (coordinate: [number, number]): VectorSelectionBBox | null => {
      if (!firstCorner) {
        setFirstCorner(coordinate)
        return null
      }
      setFirstCorner(null)
      setDrawing(false)
      return normalizeBboxFromCorners(firstCorner, coordinate)
    },
    [firstCorner],
  )

  const reset = useCallback(() => {
    setFirstCorner(null)
    setDrawing(false)
  }, [])

  const showBbox = useCallback((bbox: VectorSelectionBBox | null) => {
    setBboxInput(bboxToInputState(bbox))
  }, [])

  return {
    drawing,
    setDrawing,
    firstCorner,
    bboxInput,
    setBboxInput,
    typedBbox: parseBboxInput(bboxInput),
    placeCorner,
    reset,
    showBbox,
  }
}