import { createAsyncThunk, createSlice } from '@reduxjs/toolkit';
import { auth, company } from '../api';

export const bootstrapSession = createAsyncThunk('auth/bootstrap', async (session) => {
  if (session) return session;
  return auth.me();
});

export const loginWithGoogle = createAsyncThunk('auth/login', async (credential) => {
  const { session } = await auth.loginWithGoogle(credential);
  if (!session?.user) {
    throw new Error('Login ok but session cookie not accepted (/api/auth/me still unauthorized)');
  }
  return session;
});

export const selectCompany = createAsyncThunk('auth/selectCompany', async (companyId) => {
  const data = await company.select(companyId);
  return data.user ?? { selectedCompanyId: companyId };
});

export const createCompany = createAsyncThunk('auth/createCompany', async (payload) => {
  const data = await company.create(payload);
  if (data.user) return data.user;
  if (data.company?.id) {
    const selected = await company.select(data.company.id);
    return selected.user ?? { selectedCompanyId: data.company.id };
  }
  throw new Error('Unternehmen angelegt, aber keine Benutzerdaten erhalten.');
});

export const logout = createAsyncThunk('auth/logout', async () => {
  await auth.logout();
  window.history.replaceState(null, '', '/');
});

function mergeUser(state, incoming) {
  if (!incoming) return state.user;
  const selectedCompanyId =
    incoming.selectedCompanyId ?? state.user?.selectedCompanyId ?? null;
  return { ...state.user, ...incoming, selectedCompanyId };
}

const initialState = {
  user: null,
  googleClientId: null,
  status: 'loading',
};

const authSlice = createSlice({
  name: 'auth',
  initialState,
  reducers: {},
  extraReducers: (builder) => {
    builder
      .addCase(bootstrapSession.fulfilled, (state, action) => {
        const session = action.payload;
        state.googleClientId = session.googleClientId ?? state.googleClientId;
        if (!session.user) {
          if (state.status !== 'authed') {
            state.user = null;
            state.status = 'anon';
          }
          return;
        }
        state.user = mergeUser(state, session.user);
        state.status = 'authed';
      })
      .addCase(bootstrapSession.rejected, (state) => {
        if (state.status === 'loading') {
          state.user = null;
          state.status = 'anon';
        }
      })
      .addCase(loginWithGoogle.fulfilled, (state, action) => {
        const session = action.payload;
        state.user = session.user;
        state.googleClientId = session.googleClientId ?? state.googleClientId;
        state.status = 'authed';
      })
      .addCase(loginWithGoogle.rejected, (state) => {
        state.user = null;
        state.status = 'anon';
      })
      .addCase(selectCompany.fulfilled, (state, action) => {
        state.user = mergeUser(state, action.payload);
        state.status = 'authed';
      })
      .addCase(createCompany.fulfilled, (state, action) => {
        state.user = mergeUser(state, action.payload);
        state.status = 'authed';
      })
      .addCase(createCompany.rejected, (state, action) => {
        console.error('[redux] createCompany.rejected', action.error?.message, action.payload);
      })
      .addCase(logout.fulfilled, (state) => {
        state.user = null;
        state.status = 'anon';
      });
  },
});

export const selectAuthStatus = (state) => state.auth.status;
export const selectAuthUser = (state) => state.auth.user;
export const selectGoogleClientId = (state) => state.auth.googleClientId;
export const selectNeedsCompanySetup = (state) =>
  state.auth.status === 'authed' && state.auth.user?.selectedCompanyId == null;

export default authSlice.reducer;