import type { DragMoveEvent, DragStartEvent } from '@dnd-kit/core'
import React from 'react'
import { useGridContext } from '../../../context/grid-context/hook'
import type { ColumnState } from '../../../state'
import { DRAG_TYPE_HEADER_GROUP_CELL } from '../constants'
import type { ColumnCompare } from './utils'

import { calculateColumnMoving, calculateGroupMoving } from './utils'
import {
    buildHeaderHierarchy,
    getLowestLeafs,
} from '../../../state/reducer/column-utils'

export const useColumnMove = () => {
    const grid = useGridContext()
    const initialColumnIdsWhileMoving = React.useRef<string[] | null>(null)
    const [columnsWhileMoving, setColumnsWhileMoving] = React.useState<
        ColumnState[] | null
    >(null)
    const [movedColumnIndex, setMovedColumnIndex] = React.useState<
        number | null
    >(null)

    const [moveState, setMoveState] = React.useState<{
        id: string
        columnIds: string[]
        order: string[]
        initialX: number
        bounds: {
            initialLeft: number
            locations: ColumnCompare[]
            currentIndex: number
            maxIndex: number
            minIndex: number
            minLeft: number
            maxLeft: number
        }
    } | null>(null)

    const onMoveStart = React.useCallback(
        (id: string, e: DragStartEvent) => {
            const state = grid.getState()
            const columnIdsState =
                grid.selectors.selectColumnIdsWithHidden(state)
            const hiddenIds = grid.selectors.selectHiddenIds(state)
            const columns = columnIdsState.map(
                (id) => state.columns.entities[id]
            )

            const getGroup = (id: string) => state.columns.entities[id]
            const isGroup = !!getGroup(id).isParent
            const lowestLeafs = isGroup
                ? getLowestLeafs(id, state.columns.entities, [])
                : []
            const columnIds = isGroup
                ? lowestLeafs
                      .map((c) => c.id)
                      .sort(
                          (a, b) =>
                              columnIdsState.indexOf(a) -
                              columnIdsState.indexOf(b)
                      )
                : [id]

            const entities = grid.selectors.selectColumnEntities(state)
            const headerHierarchy = buildHeaderHierarchy(entities, [])

            setColumnsWhileMoving(columns)
            initialColumnIdsWhileMoving.current = columnIdsState

            const bounds = isGroup
                ? calculateGroupMoving(
                      id,
                      columns,
                      headerHierarchy.groups,
                      getGroup,
                      hiddenIds
                  )
                : calculateColumnMoving(
                      id,
                      columns,
                      headerHierarchy.groups,
                      getGroup,
                      hiddenIds
                  )

            setMoveState({
                id,
                columnIds,
                initialX: e.active.rect.current.initial?.left ?? 0,
                order: columns.map((c) => c.id),
                bounds,
            })
        },
        [grid]
    )

    const onMove = React.useCallback(
        (e: DragMoveEvent) => {
            if (!moveState) {
                return
            }
            const { bounds, columnIds } = moveState
            const { initialLeft, currentIndex, locations, maxIndex, minIndex } =
                bounds
            const diff = e.delta.x
            const newLeft = initialLeft + diff

            const leftMost = locations.find(
                ({ location, compare }) =>
                    compare === 'less' && newLeft < location
            )
            const rightMost = [...locations]
                .reverse()
                .find(
                    ({ location, compare }) =>
                        compare === 'more' &&
                        newLeft +
                            (e.active.data.current?.type ===
                            DRAG_TYPE_HEADER_GROUP_CELL
                                ? (e.active.rect.current.initial?.width ?? 0)
                                : 0) *
                                0.5 >
                            location
                )

            let { newIndex } = leftMost ??
                rightMost ?? {
                    newIndex: currentIndex,
                }

            newIndex = Math.max(minIndex, Math.min(maxIndex, newIndex))

            setMovedColumnIndex(newIndex)

            if (movedColumnIndex !== newIndex) {
                let ids = columnsWhileMoving!.map((c) => c.id)
                if (newIndex !== currentIndex) {
                    ids = ids.filter((cid) => !columnIds.includes(cid))

                    const modifiedIndex =
                        newIndex > currentIndex
                            ? newIndex - (columnIds.length - 1) //Take into account multiple columns being moved
                            : newIndex

                    ids.splice(modifiedIndex, 0, ...columnIds)
                }

                grid.api.column.reorderColumns(ids)
            }
        },
        [moveState, columnsWhileMoving, movedColumnIndex, grid]
    )

    const onMoveEnd = React.useCallback(() => {
        setMoveState(null)
        setMovedColumnIndex(null)
        setColumnsWhileMoving(null)
        grid.events.emit('onColumnStateChange')
        initialColumnIdsWhileMoving.current = null
    }, [grid])

    const onMoveCancel = React.useCallback(() => {
        grid.api.column.reorderColumns(initialColumnIdsWhileMoving.current!)
        onMoveEnd()
    }, [grid.api.column, onMoveEnd])

    return {
        minLeft: moveState?.bounds.minLeft ?? 0,
        maxLeft: moveState?.bounds.maxLeft ?? Infinity,
        onMoveStart,
        onMove,
        onMoveEnd,
        onMoveCancel,
    }
}