const config = require("../config/index");
const { formatDate } = require("../utils/date");
const { safeGetStorage, safeSetStorage } = require("../utils/storage");
const { normalizeRegionArray, deriveRegionFromParts, getRegionParts } = require("../utils/region");

const STORAGE_KEYS = {
  history: "fortune:history",
  quotaPrefix: "fortune:quota:",
  form: "fortune:form"
};

function createDefaultForm() {
  return {
    birthDate: formatDate(new Date()),
    birthTime: "",
    birthProvince: "",
    birthCity: "",
    birthDistrict: "",
    birthRegion: []
  };
}

function normalizeForm(payload, fallback) {
  const base = fallback || createDefaultForm();
  const toStringValue = (value, fallbackValue = "") => (typeof value === "string" ? value : fallbackValue);
  const normalized = {
    birthDate: toStringValue(payload && payload.birthDate, base.birthDate),
    birthTime: toStringValue(payload && payload.birthTime, base.birthTime || ""),
    birthProvince: toStringValue(payload && payload.birthProvince, base.birthProvince || ""),
    birthCity: toStringValue(payload && payload.birthCity, base.birthCity || ""),
    birthDistrict: toStringValue(payload && payload.birthDistrict, base.birthDistrict || ""),
    birthRegion: []
  };
  const persistedRegion = normalizeRegionArray(payload && payload.birthRegion);
  const baseRegion = normalizeRegionArray(base.birthRegion);
  if (persistedRegion.length) {
    normalized.birthRegion = persistedRegion;
  } else if (baseRegion.length) {
    normalized.birthRegion = baseRegion;
  } else {
    normalized.birthRegion = deriveRegionFromParts({
      province: normalized.birthProvince,
      city: normalized.birthCity,
      district: normalized.birthDistrict
    });
  }
  const parts = getRegionParts(normalized.birthRegion, {
    province: normalized.birthProvince,
    city: normalized.birthCity,
    district: normalized.birthDistrict
  });
  normalized.birthProvince = parts.province;
  normalized.birthCity = parts.city;
  normalized.birthDistrict = parts.district;
  return normalized;
}

function loadPersistedForm() {
  const stored = safeGetStorage(STORAGE_KEYS.form, null);
  if (stored && typeof stored === "object") {
    return normalizeForm(stored);
  }
  const defaults = createDefaultForm();
  safeSetStorage(STORAGE_KEYS.form, defaults);
  return defaults;
}

function persistForm(form) {
  const normalized = normalizeForm(form);
  safeSetStorage(STORAGE_KEYS.form, normalized);
}

const state = {
  form: loadPersistedForm(),
  currentFortune: null,
  history: [],
  quota: {
    date: "",
    count: 0
  },
  lastError: ""
};

function getQuotaStorageKey(dateStr) {
  return `${STORAGE_KEYS.quotaPrefix}${dateStr.replace(/-/g, "")}`;
}

function syncQuota() {
  const today = formatDate(new Date());
  const storageKey = getQuotaStorageKey(today);
  const stored = safeGetStorage(storageKey, 0);
  const count = typeof stored === "number" ? stored : 0;
  state.quota = {
    date: today,
    count
  };
}

function incrementQuota() {
  const today = formatDate(new Date());
  if (state.quota.date !== today) {
    syncQuota();
  }
  const nextCount = state.quota.count + 1;
  state.quota = {
    date: today,
    count: nextCount
  };
  safeSetStorage(getQuotaStorageKey(today), nextCount);
}

function canGenerateToday() {
  const today = formatDate(new Date());
  if (state.quota.date !== today) {
    syncQuota();
  }
  return state.quota.count < config.maxDailyQuota;
}

function loadHistory() {
  const stored = safeGetStorage(STORAGE_KEYS.history, []);
  state.history = Array.isArray(stored) ? stored : [];
}

function saveHistory() {
  safeSetStorage(STORAGE_KEYS.history, state.history);
}

function appendHistory(formSnapshot, fortune) {
  const snapshot = normalizeForm(formSnapshot, state.form);
  const entry = {
    id: `${Date.now()}_${Math.random().toString(36).slice(2, 6)}`,
    createdAt: new Date().toISOString(),
    formSnapshot: snapshot,
    fortune
  };
  const next = [entry, ...state.history];
  state.history = next.slice(0, config.historyLimit);
  saveHistory();
  return entry;
}

function getHistoryById(id) {
  return state.history.find((item) => item.id === id);
}

function setForm(partial) {
  const merged = Object.assign({}, state.form, partial);
  state.form = normalizeForm(merged, state.form);
  persistForm(state.form);
}

function setCurrentFortune(fortune) {
  state.currentFortune = fortune;
}

function getState() {
  return state;
}

function initStore() {
  syncQuota();
  loadHistory();
}

module.exports = {
  initStore,
  getState,
  setForm,
  setCurrentFortune,
  appendHistory,
  loadHistory,
  getHistoryById,
  canGenerateToday,
  incrementQuota
};