import { useId, useState } from 'react'
import { useRegulars } from '../dinners/api.ts'
import { useQuestLog, type QuestLogDinner } from '../discover/api.ts'
import { details } from '../discover/QuestLogSheet.tsx'
import { ErrorBanner } from '../ui/ErrorBanner.tsx'
import { ListRow } from '../ui/ListRow.tsx'
import { Photo } from '../ui/Photo.tsx'
import { Segmented } from '../ui/Segmented.tsx'
import { Sheet } from '../ui/Sheet.tsx'
import { Skeleton } from '../ui/Skeleton.tsx'
import { Tag } from '../ui/Tag.tsx'
import type { PlanDay, Swap } from './api.ts'
import { weekdayName } from './week.ts'
import styles from './SwapSheet.module.css'

// Source is a list a dinner is swapped in from.
export type Source = 'quest_log' | 'regulars'

export const sourceNames: Record<Source, string> = { quest_log: 'Quest log', regulars: 'Regulars' }

export const emptyLists: Record<Source, string> = {
  quest_log: 'Your Quest log is empty — swipe right on a Side quest to add one.',
  regulars: 'You have no Regulars yet.',
}

export type SwapSheetProps = {
  // The day being swapped.
  day: PlanDay
  // The ids of the dinners already on the week's plan.
  planned: ReadonlySet<string>
  onSwap: (swap: Swap) => void
  onClose: () => void
}

// SwapSheet is the mobile swap sheet: the Quest log and the Regulars, as
// desktop's plan panel lists them, segmented "Quest log · N | Regulars · N",
// each dinner with its 48 px photo, name, difficulty and minutes. Choosing a
// dinner swaps it into the day; a dinner already this week can't be chosen.
export function SwapSheet({ day, planned, onSwap, onClose }: SwapSheetProps) {
  const titleId = useId()
  const questLog = useQuestLog()
  const regulars = useRegulars()
  const [source, setSource] = useState<Source>('quest_log')
  const lists = { quest_log: questLog, regulars }
  const list = lists[source]

  const label = (s: Source) => {
    const dinners = lists[s].data
    return dinners === undefined ? sourceNames[s] : `${sourceNames[s]} · ${dinners.length}`
  }

  let body
  if (list.isError) {
    body = (
      <ErrorBanner onRetry={() => void list.refetch()}>
        Couldn't load your {sourceNames[source]}. {list.error.message}
      </ErrorBanner>
    )
  } else if (list.isPending) {
    body = (
      <div aria-busy="true" aria-label={`${sourceNames[source]} loading`} className={styles.rows}>
        {Array.from({ length: 3 }, (_, i) => (
          <Skeleton key={i} className={styles.skeletonRow} />
        ))}
      </div>
    )
  } else if (list.data.length === 0) {
    body = <p className={styles.empty}>{emptyLists[source]}</p>
  } else {
    body = (
      <ul aria-label={sourceNames[source]} className={styles.rows}>
        {list.data.map((dinner: QuestLogDinner) => {
          const already = planned.has(dinner.id)
          return (
            <li key={dinner.id}>
              <ListRow
                className={already ? styles.already : undefined}
                leading={
                  // The row's name already says what the photo shows.
                  <span aria-hidden="true">
                    <Photo id={dinner.photo_id} name={dinner.name} radius="var(--radius-md)" sizes="48px" className={styles.photo} />
                  </span>
                }
                title={dinner.name}
                meta={details(dinner)}
                // A dinner already this week is no button: it can't be chosen.
                onClick={
                  already
                    ? undefined
                    : () =>
                        onSwap({
                          date: day.date,
                          dinner: { id: dinner.id, name: dinner.name, photo_id: dinner.photo_id, minutes: dinner.minutes_total },
                          fromQuestLog: source === 'quest_log',
                        })
                }
                trailing={already && <Tag>Already this week</Tag>}
              />
            </li>
          )
        })}
      </ul>
    )
  }

  return (
    <Sheet open onClose={onClose} aria-labelledby={titleId}>
      <div className={styles.sheet}>
        <div>
          <h2 id={titleId} className={styles.title}>
            Swap {weekdayName(day.date)}
          </h2>
          <p className={styles.replaces}>Replaces {day.dinner.name}</p>
        </div>
        <Segmented
          label="Swap in from"
          options={[
            { value: 'quest_log', label: label('quest_log') },
            { value: 'regulars', label: label('regulars') },
          ]}
          value={source}
          onValueChange={setSource}
        />
        {body}
      </div>
    </Sheet>
  )
}