import { atom } from "jotai";
import {
  getDefaultSettings,
  getDefaultHabitsData,
  getDefaultCoinsData,
  getDefaultWishlistData,
  Habit,
  ViewType,
  getDefaultUsersData,
} from "./types";
import {
  getTodayInTimezone,
  isSameDate,
  t2d,
  calculateCoinsEarnedToday,
  calculateTotalEarned,
  calculateTotalSpent,
  calculateCoinsSpentToday,
  calculateTransactionsToday,
  getCompletionsForToday,
  getISODate
} from "@/lib/utils";
import { atomWithStorage } from "jotai/utils";

export interface BrowserSettings {
  viewType: ViewType
}

export const browserSettingsAtom = atomWithStorage('browserSettings', {
  viewType: 'habits'
} as BrowserSettings)

export const usersAtom = atom(getDefaultUsersData())
export const settingsAtom = atom(getDefaultSettings());
export const habitsAtom = atom(getDefaultHabitsData());
export const coinsAtom = atom(getDefaultCoinsData());
export const wishlistAtom = atom(getDefaultWishlistData());

// Derived atom for coins earned today
export const coinsEarnedTodayAtom = atom((get) => {
  const coins = get(coinsAtom);
  const settings = get(settingsAtom);
  return calculateCoinsEarnedToday(coins.transactions, settings.system.timezone);
});

// Derived atom for total earned
export const totalEarnedAtom = atom((get) => {
  const coins = get(coinsAtom);
  return calculateTotalEarned(coins.transactions);
});

// Derived atom for total spent
export const totalSpentAtom = atom((get) => {
  const coins = get(coinsAtom);
  return calculateTotalSpent(coins.transactions);
});

// Derived atom for coins spent today
export const coinsSpentTodayAtom = atom((get) => {
  const coins = get(coinsAtom);
  const settings = get(settingsAtom);
  return calculateCoinsSpentToday(coins.transactions, settings.system.timezone);
});

// Derived atom for transactions today
export const transactionsTodayAtom = atom((get) => {
  const coins = get(coinsAtom);
  const settings = get(settingsAtom);
  return calculateTransactionsToday(coins.transactions, settings.system.timezone);
});

// Derived atom for current balance from all transactions
export const coinsBalanceAtom = atom((get) => {
  const coins = get(coinsAtom);
  return coins.transactions.reduce((sum, transaction) => sum + transaction.amount, 0);
});

/* transient atoms */
interface PomodoroAtom {
  show: boolean
  selectedHabitId: string | null
  autoStart: boolean
  minimized: boolean
}

export const pomodoroAtom = atom<PomodoroAtom>({
  show: false,
  selectedHabitId: null,
  autoStart: true,
  minimized: false,
})

export const userSelectAtom = atom<boolean>(false)

// Derived atom for *fully* completed habits by date, respecting target completions
export const completedHabitsMapAtom = atom((get) => {
  const habits = get(habitsAtom).habits
  const timezone = get(settingsAtom).system.timezone

  const map = new Map<string, Habit[]>()

  habits.forEach(habit => {
    // Group completions by date
    const completionsByDate = new Map<string, number>()

    habit.completions.forEach(completion => {
      const dateKey = getISODate({ dateTime: t2d({ timestamp: completion, timezone }), timezone })
      completionsByDate.set(dateKey, (completionsByDate.get(dateKey) || 0) + 1)
    })

    // Check if habit meets target completions for each date
    completionsByDate.forEach((count, dateKey) => {
      const target = habit.targetCompletions || 1
      if (count >= target) {
        if (!map.has(dateKey)) {
          map.set(dateKey, [])
        }
        map.get(dateKey)!.push(habit)
      }
    })
  })

  return map
})


export const pomodoroTodayCompletionsAtom = atom((get) => {
  const pomo = get(pomodoroAtom)
  const habits = get(habitsAtom)
  const settings = get(settingsAtom)

  if (!pomo.selectedHabitId) return 0

  const selectedHabit = habits.habits.find(h => h.id === pomo.selectedHabitId!)
  if (!selectedHabit) return 0

  return getCompletionsForToday({
    habit: selectedHabit,
    timezone: settings.system.timezone
  })
})

// Derived atom to check if any habits are tasks
export const hasTasksAtom = atom((get) => {
  const habits = get(habitsAtom)
  return habits.habits.some(habit => habit.isTask === true)
})