import { useQuery } from '@tanstack/react-query'
import { useApi } from '../api/index.ts'
import { isRecord } from '../api/errors.ts'
import { oneOf, photoId } from '../dinners/api.ts'
import { weekLabel } from '../plan/week.ts'

export const HOME_PATH = '/api/v1/home'
export const HOME_KEY = ['home'] as const

export const ORIGINS = ['regular', 'side_quest'] as const
export type Origin = (typeof ORIGINS)[number]

// Tonight is the dinner planned for today: photo_id is its stored photo's
// id, from photo, and minutes_total its minutes from prep to table, null
// when the recipe does not say.
export type Tonight = { id: string; name: string; photo_id: string | undefined; origin: Origin; minutes_total: number | null }

// ShoppingListStatus is the Supply run Home points at: next week's once it
// has one, otherwise this week's, ready when that week has a list.
// weekStart is the week's Monday, YYYY-MM-DD, and dates the week as the
// status row shows it, "Oct 5–11" (the API's label is the long "Week 41 ·
// Oct 5 – 11").
export type ShoppingListStatus = { weekStart: string; dates: string; ready: boolean }

// Home is GET /api/v1/home: dateLabel is today, household-local, "Friday,
// Oct 2"; tonight is null when today has no plan; sideQuestCount is how
// many Side quests wait in the deck; unread says the Recent updates hold
// something not yet seen.
export type Home = {
  dateLabel: string
  tonight: Tonight | null
  sideQuestCount: number
  shoppingList: ShoppingListStatus
  unread: boolean
}

function parseTonight(where: string, body: unknown): Tonight | null {
  if (body === null) return null
  if (!isRecord(body) || typeof body.id !== 'string' || typeof body.name !== 'string') {
    throw new Error(`${where}: tonight is not a dinner`)
  }
  if (body.minutes_total !== null && !Number.isInteger(body.minutes_total)) {
    throw new Error(`${where}: tonight's minutes_total is not a whole number`)
  }
  return {
    id: body.id,
    name: body.name,
    photo_id: photoId(where, body.photo),
    origin: oneOf(where, 'origin', ORIGINS, body.origin),
    minutes_total: body.minutes_total as number | null,
  }
}

// parseHome checks a GET /api/v1/home body.
export function parseHome(where: string, body: unknown): Home {
  if (!isRecord(body) || typeof body.dateLabel !== 'string') throw new Error(`${where}: response is not the home`)
  if (!Number.isInteger(body.sideQuestCount) || (body.sideQuestCount as number) < 0) {
    throw new Error(`${where}: sideQuestCount is not a count`)
  }
  const list = body.shoppingList
  if (!isRecord(list) || typeof list.weekStart !== 'string' || typeof list.ready !== 'boolean') {
    throw new Error(`${where}: shoppingList is not a week's Supply run status`)
  }
  const updates = body.recentUpdates
  if (!isRecord(updates) || typeof updates.unread !== 'boolean') throw new Error(`${where}: recentUpdates has no unread flag`)
  return {
    dateLabel: body.dateLabel,
    tonight: parseTonight(where, body.tonight),
    sideQuestCount: body.sideQuestCount as number,
    shoppingList: { weekStart: list.weekStart, dates: weekLabel(list.weekStart).dates.replace(' – ', '–'), ready: list.ready },
    unread: updates.unread,
  }
}

// useHome is the Home screen's summary (GET /api/v1/home).
export function useHome() {
  const { apiFetch } = useApi()
  return useQuery({
    queryKey: HOME_KEY,
    queryFn: async () => parseHome(`GET ${HOME_PATH}`, await apiFetch<unknown>(HOME_PATH)),
  })
}