import { createSlice, createAsyncThunk, PayloadAction } from '@reduxjs/toolkit';
import { fetchI18nMessages, I18nMessages } from '../API/i18n/i18nActions';

export interface I18nState {
  messages: I18nMessages;
  currentLocale: string;
  supportedLocales: string[];
  loading: boolean;
  error: string | null;
}

const initialState: I18nState = {
  messages: {},
  currentLocale: 'en',
  supportedLocales: ['en', 'zh'],
  loading: false,
  error: null,
};

// 异步thunk：加载多语言资源
export const loadI18nMessages = createAsyncThunk(
  'i18n/loadMessages',
  async (locale: string) => {
    const messages = await fetchI18nMessages(locale);
    return { locale, messages };
  }
);

const i18nSlice = createSlice({
  name: 'i18n',
  initialState,
  reducers: {
    setCurrentLocale: (state, action: PayloadAction<string>) => {
      state.currentLocale = action.payload;
    },
    clearError: (state) => {
      state.error = null;
    },
  },
  extraReducers: (builder) => {
    builder
      .addCase(loadI18nMessages.pending, (state) => {
        state.loading = true;
        state.error = null;
      })
      .addCase(loadI18nMessages.fulfilled, (state, action) => {
        state.loading = false;
        state.messages = action.payload.messages;
        state.currentLocale = action.payload.locale;
      })
      .addCase(loadI18nMessages.rejected, (state, action) => {
        state.loading = false;
        state.error = action.error.message || 'Failed to load i18n messages';
      });
  },
});

export const { setCurrentLocale, clearError } = i18nSlice.actions;
export default i18nSlice.reducer;