import { BASE_URL } from "@/constants/config";
import api from "@/services/axiosClient";
import { toCamel } from "@/utils/Payments";
import { createSlice, PayloadAction, createAsyncThunk } from "@reduxjs/toolkit";
import { AxiosError } from "axios";

type LastEmiStatus = "pending" | "completed";

export interface MyPlan {
  noOfEmi: number | null;
  totalAmount: number | null;
  downPayment: number | null;
  emiAmount: number | null;
  totalEmi: number | null;
  installmentPaid: number | null;
  currentAmount: number | null;
}

export interface EmiDetails {
  dueAmount: number | null;
  totalAmountPaidInCurrentCycle: number | null;
  dueDate: string | null;
  status: LastEmiStatus | null;
  advanceBalance: number | null;
  pendingCycles: number | null;
  totalPendingInstallments: number | null;
  myPlan: MyPlan;
}

type LoadingState = "idle" | "pending" | "succeeded" | "failed";

export interface EmiDetailsState {
  item?: EmiDetails;
  loading: LoadingState;
  error?: string;
  lastFetchedAt?: number;
}

const initialState: EmiDetailsState = {
  item: undefined,
  loading: "idle",
  error: undefined,
  lastFetchedAt: undefined,
};

export interface MyPlanApi {
  no_of_emi: number | null;
  total_amount: number | null;
  down_payment: number | null;
  emi_amount: number | null;
  total_emi: number | null;
  installment_paid: number | null;
  current_amount: number | null;
}

export interface EmiDetailsApi {
  due_amount: number | null;
  total_amount_paid_in_current_cycle: number | null;
  due_date: string | null;
  status: LastEmiStatus | null;
  advance_balance: number | null;
  pending_cycles: number | null;
  total_pending_installments: number | null;
  myPlain: MyPlanApi;
}

export interface EmiDetailsResponse {
  success: boolean;
  data: EmiDetailsApi[];
}

const mapEmiDetailsApiToModel = (apiObj: EmiDetailsApi): EmiDetails => ({
  dueAmount: apiObj.due_amount,
  totalAmountPaidInCurrentCycle: apiObj.total_amount_paid_in_current_cycle,
  dueDate: apiObj.due_date,
  status: apiObj.status,
  advanceBalance: apiObj.advance_balance,
  pendingCycles: apiObj.pending_cycles,
  totalPendingInstallments: apiObj.total_pending_installments,
  myPlan: {
    noOfEmi: apiObj.myPlain.no_of_emi,
    totalAmount: apiObj.myPlain.total_amount,
    downPayment: apiObj.myPlain.down_payment,
    emiAmount: apiObj.myPlain.emi_amount,
    totalEmi: apiObj.myPlain.total_emi,
    installmentPaid: apiObj.myPlain.installment_paid,
    currentAmount: apiObj.myPlain.current_amount,
  },
});

export const fetchEmiDetails = createAsyncThunk<
  EmiDetails,
  void,
  { rejectValue: string }
>("emiDetails/fetch", async (_: void, { rejectWithValue }) => {
  try {
    const res = await api.get(`${BASE_URL}}/api/v1/emi-details`, {
      method: "GET",
      headers: { "Content-Type": "application/json" },
    });

    const json = res.data;

    const first = json?.data?.[0];
    if (!json?.success || !first) {
      return rejectWithValue("No EMI details found");
    }

    return mapEmiDetailsApiToModel(first);
  } catch (e: any) {
    const err = e as AxiosError<any>;
    if (err.code === "ERR_CANCELED") return rejectWithValue("Request aborted");
    const msg =
      err.response?.data?.message || err.message || "Something went wrong";
    return rejectWithValue(msg);
  }
});

const emiDetailsSlice = createSlice({
  name: "emiDetails",
  initialState,
  reducers: {
    clearEmiDetails(state) {
      state.item = undefined;
      state.error = undefined;
      state.loading = "idle";
      state.lastFetchedAt = undefined;
    },
  },
  extraReducers: (builder) => {
    builder
      .addCase(fetchEmiDetails.pending, (state) => {
        state.loading = "pending";
        state.error = undefined;
      })
      .addCase(
        fetchEmiDetails.fulfilled,
        (state, action: PayloadAction<EmiDetails>) => {
          state.loading = "succeeded";
          state.item = action.payload;
          state.lastFetchedAt = Date.now();
        }
      )
      .addCase(fetchEmiDetails.rejected, (state, action) => {
        state.loading = "failed";
        state.error = action.payload as string | undefined;
      });
  },
});

export const { clearEmiDetails } = emiDetailsSlice.actions;
export default emiDetailsSlice.reducer;