import { computed, ref } from 'vue'

import {
  buildWorkbenchDateLabel,
  canApplyWorkbenchDateSelection,
  getTodayDateValue,
  mergeWorkbenchDateLabelIntoDraft,
  stripWorkbenchDateLabelFromDraft
} from '../utils/workbenchComposerDate.js'

export function useWorkbenchComposerDate({ draft, focusInput } = {}) {
  const workbenchDatePickerOpen = ref(false)
  const workbenchDateMode = ref('single')
  const workbenchSingleDate = ref(getTodayDateValue())
  const workbenchRangeStartDate = ref(getTodayDateValue())
  const workbenchRangeEndDate = ref(getTodayDateValue())
  const workbenchDateTagLabel = ref('')

  const workbenchCanApplyDateSelection = computed(() =>
    canApplyWorkbenchDateSelection({
      mode: workbenchDateMode.value,
      singleDate: workbenchSingleDate.value,
      rangeStartDate: workbenchRangeStartDate.value,
      rangeEndDate: workbenchRangeEndDate.value
    })
  )

  function clearWorkbenchDateSelection() {
    const today = getTodayDateValue()
    workbenchDatePickerOpen.value = false
    workbenchDateMode.value = 'single'
    workbenchSingleDate.value = today
    workbenchRangeStartDate.value = today
    workbenchRangeEndDate.value = today
    workbenchDateTagLabel.value = ''
  }

  function ensureWorkbenchDateDefaults() {
    const today = getTodayDateValue()
    workbenchSingleDate.value ||= today
    workbenchRangeStartDate.value ||= workbenchSingleDate.value || today
    workbenchRangeEndDate.value ||= workbenchRangeStartDate.value || today
  }

  function toggleWorkbenchDatePicker() {
    if (workbenchDatePickerOpen.value) {
      workbenchDatePickerOpen.value = false
      return
    }

    ensureWorkbenchDateDefaults()
    workbenchDatePickerOpen.value = true
  }

  function closeWorkbenchDatePicker() {
    workbenchDatePickerOpen.value = false
  }

  function setWorkbenchDateMode(mode) {
    const today = getTodayDateValue()
    const nextMode = mode === 'range' ? 'range' : 'single'

    if (nextMode === 'range') {
      const baseDate = workbenchSingleDate.value || today
      workbenchRangeStartDate.value ||= baseDate
      workbenchRangeEndDate.value ||= workbenchRangeStartDate.value
    } else {
      workbenchSingleDate.value ||= workbenchRangeStartDate.value || today
    }

    workbenchDateMode.value = nextMode
  }

  function handleWorkbenchDatePickerOutside(event) {
    if (!workbenchDatePickerOpen.value) {
      return
    }
    if (event.target instanceof Element && event.target.closest('.workbench-date-anchor')) {
      return
    }
    workbenchDatePickerOpen.value = false
  }

  function applyWorkbenchDateSelection() {
    const label = buildWorkbenchDateLabel({
      mode: workbenchDateMode.value,
      singleDate: workbenchSingleDate.value,
      rangeStartDate: workbenchRangeStartDate.value,
      rangeEndDate: workbenchRangeEndDate.value
    })
    if (!label) {
      return
    }

    workbenchDateTagLabel.value = label
    draft.value = stripWorkbenchDateLabelFromDraft(draft.value)
    workbenchDatePickerOpen.value = false
    focusInput?.()
  }

  function handleWorkbenchDateInputChange(part = 'single') {
    if (workbenchDateMode.value !== 'range' || part === 'single') {
      applyWorkbenchDateSelection()
      return
    }

    if (part === 'range-start') {
      if (!workbenchRangeEndDate.value || workbenchRangeEndDate.value < workbenchRangeStartDate.value) {
        workbenchRangeEndDate.value = workbenchRangeStartDate.value
      }
      return
    }

    applyWorkbenchDateSelection()
  }

  function removeWorkbenchDateTag() {
    workbenchDateTagLabel.value = ''
    focusInput?.()
  }

  function buildWorkbenchPromptText(rawText = draft.value) {
    return mergeWorkbenchDateLabelIntoDraft(rawText, workbenchDateTagLabel.value)
  }

  return {
    workbenchDatePickerOpen,
    workbenchDateMode,
    workbenchSingleDate,
    workbenchRangeStartDate,
    workbenchRangeEndDate,
    workbenchDateTagLabel,
    workbenchCanApplyDateSelection,
    clearWorkbenchDateSelection,
    toggleWorkbenchDatePicker,
    closeWorkbenchDatePicker,
    setWorkbenchDateMode,
    handleWorkbenchDatePickerOutside,
    applyWorkbenchDateSelection,
    handleWorkbenchDateInputChange,
    removeWorkbenchDateTag,
    buildWorkbenchPromptText
  }
}