import XSystem from '@/core/XSystem.ts'
import type { IDesktopAppIcon } from '@/core/desktop/types/IDesktopAppIcon.ts'
import {
  computed,
  nextTick,
  onMounted,
  onUnmounted,
  reactive,
  ref,
  toRaw,
  toRefs,
  toValue,
  useTemplateRef,
  watch,
  watchEffect,
} from 'vue'
import { DesktopEventEnum } from '@/core/events/EventTypes.ts'
import { useDraggable } from '@vueuse/core'
import type { IGridTemplateParams } from '@/core/desktop/types/IGridTemplateParams.ts'

export function useDesktopInit(containerStr: string) {
  let container:HTMLElement
  // 初始值
  const gridTemplate = reactive<IGridTemplateParams>({
    cellExpectWidth: 90,
    cellExpectHeight: 110,
    cellRealWidth: 90,
    cellRealHeight: 110,
    gapX: 4,
    gapY: 4,
    colCount: 1,
    rowCount: 1
  })

  const ro = new ResizeObserver(entries => {
    const entry= entries[0]
    const containerRect = entry.contentRect
    gridTemplate.colCount = Math.floor((containerRect.width + gridTemplate.gapX) / (gridTemplate.cellExpectWidth + gridTemplate.gapX));
    gridTemplate.rowCount = Math.floor((containerRect.height + gridTemplate.gapY) / (gridTemplate.cellExpectHeight + gridTemplate.gapY));

    const w = containerRect.width - (gridTemplate.gapX * (gridTemplate.colCount - 1))
    const h = containerRect.height - (gridTemplate.gapY * (gridTemplate.rowCount - 1))
    gridTemplate.cellRealWidth = Number((w / gridTemplate.colCount).toFixed(2))
    gridTemplate.cellRealHeight = Number((h / gridTemplate.rowCount).toFixed(2))
  })

  const gridStyle = computed(() => ({
    gridTemplateColumns: `repeat(${gridTemplate.colCount}, minmax(${gridTemplate.cellExpectWidth}px, 1fr))`,
    gridTemplateRows: `repeat(${gridTemplate.rowCount}, minmax(${gridTemplate.cellExpectHeight}px, 1fr))`,
    gap: `${gridTemplate.gapX}px ${gridTemplate.gapY}px`
  }))

  onMounted(() => {
    container = document.querySelector(containerStr)!
    ro.observe(container)
  })
  onUnmounted(() => {
    ro.unobserve(container)
    ro.disconnect()
  })

  // 有桌面图标的app
  const appInfos = XSystem.instance.processManages.processInfos.filter(processInfo => !processInfo.isJustProcess)
  const oldAppIcons: IDesktopAppIcon[] = JSON.parse(localStorage.getItem('desktopAppIconInfo') || '[]')
  const appIcons: IDesktopAppIcon[] = appInfos.map((processInfo, index) => {
    const oldAppIcon = oldAppIcons.find(oldAppIcon => oldAppIcon.name === processInfo.name)

    // 左上角坐标原点，从上到下从左到右 索引从1开始
    const x = Math.floor(index / gridTemplate.rowCount) + 1
    const y = index % gridTemplate.rowCount + 1

    return {
      name: processInfo.name,
      icon: processInfo.icon,
      path: processInfo.startName,
      x: oldAppIcon ? oldAppIcon.x : x,
      y: oldAppIcon ? oldAppIcon.y : y
    }
  })

  const appIconsRef = ref(appIcons)

  watch(() => [gridTemplate.rowCount, gridTemplate.colCount], ([nRows, nCols], [oRows, oCols]) => {
    if (oCols == 1 && oRows == 1) return
    appIconsRef.value = rearrangeIcons(toRaw(appIconsRef.value), nCols, nRows, oCols, oRows)
  })

  XSystem.instance.eventManages.addEventListener(DesktopEventEnum.onDesktopAppIconPos, (iconInfo) => {
    localStorage.setItem('desktopAppIconInfo', JSON.stringify(toValue(appIconsRef.value)))
  })

  return {
    gridTemplate,
    appIconsRef,
    gridStyle
  }
}

/**
 * 重新安排图标位置
 * @param appIcons 图标信息
 * @param newCols 新的列数
 * @param newRows 新的行数
 * @param oldCols 旧的列数
 * @param oldRows 旧的行数
 */
function rearrangeIcons(
  appIcons: IDesktopAppIcon[],
  newCols: number,
  newRows: number,
  oldCols: number,
  oldRows: number
): IDesktopAppIcon[] {
  if (oldCols === newCols && oldRows === newRows) {
    return appIcons;
  }
  const occupied = new Set<string>();

  function key(x: number, y: number) {
    return `${x},${y}`;
  }

  const result: IDesktopAppIcon[] = []
  const exceed: IDesktopAppIcon[] = []

  for (const appIcon of appIcons) {
    const { x, y } = appIcon;

    if (x <= newCols && y <= newRows) {
      if (!occupied.has(key(x, y))) {
        occupied.add(key(x, y))
        result.push({ ...appIcon, x, y })
      }
    } else {
      exceed.push(appIcon)
    }
  }

  for (const appIcon of exceed) {
    // 最后格子也被占 → 从 (1,1) 开始找空位
    let placed = false;
    for (let c = 1; c <= newCols; c++) {
      for (let r = 1; r <= newRows; r++) {
        if (!occupied.has(key(c, r))) {
          occupied.add(key(c, r));
          result.push({ ...appIcon, x: c, y: r });
          placed = true;
          break;
        }
      }
      if (placed) break;
    }
  }

  return result;
}