import { useState } from 'react'
import { GripVertical, ArrowUp, ArrowDown, Plus, Trash2 } from 'lucide-react'
import Modal from '../shared/Modal'
import Tooltip from '../shared/Tooltip'
import { useNetworkMode } from '../../hooks/useNetworkMode'
import { dayLabel } from '../../utils/dayLabel'
import { deleteDayBlockedReason } from '../../utils/dayDeleteImpact'
import type { Day } from '../../types'

interface DayReorderPopupProps {
  isOpen: boolean
  days: Day[]
  t: (key: string, params?: Record<string, any>) => string
  locale: string
  onReorder: (orderedIds: number[]) => void
  onAddDay: () => void
  /** Asks to delete a day; the planner opens the question. Without it rows have no delete button. */
  onDeleteDay?: (dayId: number) => void
  onClose: () => void
}

/**
 * Modal for moving whole days around: drag a row by its grip or use the up/down
 * arrows, add a day at the end, or delete one. Day headers stay untouched, so
 * this is the single surface for ordering. Reorders are applied optimistically
 * by the store, so the list reflects each move immediately. A delete only asks:
 * the planner shows what goes with the day before anything happens.
 */
export function DayReorderPopup({ isOpen, days, t, locale, onReorder, onAddDay, onDeleteDay, onClose }: DayReorderPopupProps) {
  const [dragIndex, setDragIndex] = useState<number | null>(null)
  const [overIndex, setOverIndex] = useState<number | null>(null)
  const { offline } = useNetworkMode()

  const ordered = [...days].sort((a, b) => (a.day_number ?? 0) - (b.day_number ?? 0))
  const deleteBlocked = deleteDayBlockedReason(ordered.length, offline, t)

  const move = (from: number, to: number) => {
    if (to < 0 || to >= ordered.length || from === to) return
    const ids = ordered.map(d => d.id)
    const [moved] = ids.splice(from, 1)
    ids.splice(to, 0, moved)
    onReorder(ids)
  }

  const cellBtn = {
    display: 'grid', placeItems: 'center', width: 28, height: 28,
    border: '1px solid var(--border-faint)', borderRadius: 7,
    background: 'none', cursor: 'pointer', color: 'var(--text-muted)', padding: 0,
  } as const

  return (
    <Modal
      isOpen={isOpen}
      onClose={onClose}
      title={t('dayplan.reorderTitle')}
      size="md"
      footer={
        <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', gap: 12 }}>
          <button type="button"
            onClick={onClose}
            style={{
              padding: '8px 16px', borderRadius: 8, fontSize: 13, fontWeight: 500,
              border: '1px solid var(--border-primary)', background: 'none',
              color: 'var(--text-muted)', cursor: 'pointer', fontFamily: 'inherit',
            }}
          >
            {t('common.close')}
          </button>
          <button type="button"
            onClick={onAddDay}
            className="bg-accent text-accent-text"
            style={{
              display: 'flex', alignItems: 'center', gap: 6, padding: '8px 16px',
              borderRadius: 8, border: 'none', fontSize: 13, fontWeight: 500,
              cursor: 'pointer', fontFamily: 'inherit',
            }}
          >
            <Plus size={15} strokeWidth={2} />
            {t('dayplan.addDay')}
          </button>
        </div>
      }
    >
      <p style={{ margin: '0 0 14px', fontSize: 12.5, color: 'var(--text-faint)', lineHeight: 1.4 }}>
        {t('dayplan.reorderHint')}
      </p>

      {/* The popup is a modal, so it portals out of the planner and has to opt
          into the long-press drag itself (#1616). Without this a finger only
          selects the row text. */}
      <div data-touch-drag style={{ display: 'flex', flexDirection: 'column', gap: 4 }}>
        {ordered.map((day, index) => (
          <div
            key={day.id}
            draggable
            onDragStart={() => setDragIndex(index)}
            onDragEnd={() => { setDragIndex(null); setOverIndex(null) }}
            onDragOver={e => { e.preventDefault(); if (overIndex !== index) setOverIndex(index) }}
            onDrop={e => {
              e.preventDefault()
              if (dragIndex !== null && dragIndex !== index) move(dragIndex, index)
              setDragIndex(null); setOverIndex(null)
            }}
            style={{
              display: 'flex', alignItems: 'center', gap: 10, padding: '8px 10px',
              borderRadius: 9,
              border: '1px solid var(--border-faint)',
              background: overIndex === index && dragIndex !== null && dragIndex !== index ? 'var(--bg-hover)' : 'var(--bg-card, white)',
              opacity: dragIndex === index ? 0.5 : 1,
              outline: overIndex === index && dragIndex !== null && dragIndex !== index ? '2px dashed var(--border-primary)' : 'none',
              outlineOffset: -2,
            }}
          >
            <GripVertical size={15} strokeWidth={1.8} style={{ cursor: 'grab', color: 'var(--text-faint)', flexShrink: 0 }} />
            <span style={{
              flexShrink: 0, width: 24, height: 24, borderRadius: '50%',
              background: 'var(--bg-hover)', color: 'var(--text-muted)',
              display: 'grid', placeItems: 'center', fontSize: 11, fontWeight: 700,
            }}>
              {index + 1}
            </span>
            <span style={{ flex: 1, minWidth: 0, fontSize: 13.5, fontWeight: 500, overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>
              {dayLabel(day, index, t, locale)}
            </span>
            <button
              type="button"
              onClick={() => move(index, index - 1)}
              disabled={index === 0}
              aria-label={t('dayplan.moveUp')}
              style={{ ...cellBtn, opacity: index === 0 ? 0.35 : 1, cursor: index === 0 ? 'default' : 'pointer' }}
            >
              <ArrowUp size={14} strokeWidth={2} />
            </button>
            <button
              type="button"
              onClick={() => move(index, index + 1)}
              disabled={index === ordered.length - 1}
              aria-label={t('dayplan.moveDown')}
              style={{ ...cellBtn, opacity: index === ordered.length - 1 ? 0.35 : 1, cursor: index === ordered.length - 1 ? 'default' : 'pointer' }}
            >
              <ArrowDown size={14} strokeWidth={2} />
            </button>
            {onDeleteDay && (
              <>
                <span aria-hidden="true" className="mx-0.5 h-5 w-px flex-shrink-0 bg-edge-faint" />
                <Tooltip label={deleteBlocked ?? t('dayplan.deleteDay')} placement="left">
                  <span className="inline-flex flex-shrink-0">
                    <button
                      type="button"
                      onClick={() => onDeleteDay(day.id)}
                      disabled={!!deleteBlocked}
                      aria-label={t('dayplan.deleteDay')}
                      className="grid h-7 w-7 place-items-center rounded-[7px] border border-edge-faint text-content-muted transition-colors hover:bg-danger-soft hover:text-danger focus-visible:bg-danger-soft focus-visible:text-danger disabled:cursor-default disabled:opacity-35 disabled:hover:bg-transparent disabled:hover:text-content-muted"
                    >
                      <Trash2 size={14} strokeWidth={2} />
                    </button>
                  </span>
                </Tooltip>
              </>
            )}
          </div>
        ))}
      </div>
    </Modal>
  )
}