import { api } from "src/boot/axios";
import { isProxy, toRaw } from "vue";
import { normalizeExpense, validateExpenseUI } from "../../utils/expenses-validators";
import type { ExpenseType } from "../../types/expense.types";
import { ExpensesApiError } from "../../types/expense-validation.interface";
import type { 
  ExpensePayload, 
  PayPeriodExpenses, 
  TimesheetExpense, 
  UpsertExpenseResult, 
  UpsertExpensesBody, 
  UpsertExpensesResponse 
} from "../../types/expense.interfaces";

/* eslint-disable */
const toPlain = <T extends object>(obj:T): T => {
    const raw = isProxy(obj) ? toRaw(obj) : obj;
    if( typeof (globalThis as any).structuredClone === 'function') {
        return (globalThis as any).structuredClone(raw);
    }
    return JSON.parse(JSON.stringify(raw));
};

const normalizePayload = (expense: ExpensePayload): ExpensePayload => {
    const exp = normalizeExpense(expense as unknown as TimesheetExpense);
    const out: ExpensePayload = {
        date: exp.date,
        type: exp.type as ExpenseType,
        comment: exp.comment || '',
    };
    if(typeof exp.amount  === 'number') out.amount  = exp.amount;
    if(typeof exp.mileage === 'number') out.mileage = exp.mileage;
    return out;
}

//GET by email, year and period no
export const getPayPeriodExpenses = async (
    email: string,
    pay_year: number,
    pay_period_no: number
) : Promise<PayPeriodExpenses> => {
    const encoded_email = encodeURIComponent(email);
    const encoded_year  = encodeURIComponent(String(pay_year));
    const encoded_pay_period_no = encodeURIComponent(String(pay_period_no));

    try {
        const { data } = await api.get<PayPeriodExpenses>(`/expenses/${encoded_email}/${encoded_year}/${encoded_pay_period_no}`);

        const items = Array.isArray(data.expenses) ? data.expenses.map(normalizeExpense) : [];
        return {
            ...data,
            expenses: items,
        };
    } catch(err:any) {
        const status_code: number = err?.response?.status ?? 500;
        const data = err?.response?.data ?? {};
        throw new ExpensesApiError({
            status_code,
            error_code: data.error_code,
            message: data.message || data.error || err.message,
            context: data.context,
        });
    }
};

//PUT by email, year and period no
export const putPayPeriodExpenses = async (
    email: string,
    pay_year: number,
    pay_period_no: number,
    expenses: TimesheetExpense[]
): Promise<PayPeriodExpenses> => {
    const encoded_email = encodeURIComponent(email);
    const encoded_year  = encodeURIComponent(String(pay_year));
    const encoded_pay_period_no = encodeURIComponent(String(pay_period_no));

    const plain = Array.isArray(expenses) ? expenses.map(toPlain): [];

    const normalized: ExpensePayload[] = plain.map((exp) => {
        const norm = normalizeExpense(exp as TimesheetExpense);
        validateExpenseUI(norm, 'expense_item');        
        return normalizePayload(norm as unknown as ExpensePayload);
    });

    const body: UpsertExpensesBody = {expenses: normalized};

    try {
        const { data } = await api.put<UpsertExpensesResponse>(
            `/expenses/${encoded_email}/${encoded_year}/${encoded_pay_period_no}`,
            body,
            { headers: {'Content-Type': 'application/json'}}
        );

        const items = Array.isArray(data?.data?.expenses)
        ? data.data.expenses.map(normalizeExpense)
        : [];
        return {
            ...(data?.data ?? {
                pay_period_no,
                pay_year,
                employee_email: email,
                is_approved: false,
                expenses: [],
                totals: {amount: 0, mileage: 0},
            }),
            expenses: items,
        };
    } catch (err: any) {
        const status_code: number = err?.response?.status ?? 500;
        const data = err?.response?.data ?? {};
        throw new ExpensesApiError({
            status_code,
            error_code: data.error_code,
            message: data.message || data.error || err.message,
            context: data.context,
        });
    }
};

export const postPayPeriodExpenses = async (
  email: string,
  pay_year: number,
  pay_period_no: number,
  new_expenses: TimesheetExpense[]
): Promise<PayPeriodExpenses> => {
  const encoded_email = encodeURIComponent(email);
  const encoded_year = encodeURIComponent(String(pay_year));
  const encoded_pp = encodeURIComponent(String(pay_period_no));

  const plain = Array.isArray(new_expenses) ? new_expenses.map(toPlain) : [];
  const normalized: ExpensePayload[] = plain.map((exp) => {
    const norm = normalizeExpense(exp as TimesheetExpense);
    validateExpenseUI(norm, 'expense_item');
    return normalizePayload(norm as unknown as ExpensePayload);
  });

  const body: UpsertExpensesBody = { expenses: normalized };

  try {
    const { data } = await api.post<UpsertExpensesResponse>(
      `/expenses/${encoded_email}/${encoded_year}/${encoded_pp}`,
      body,
      { headers: { 'content-type': 'application/json' } }
    );
    const items = Array.isArray(data?.data?.expenses)
      ? data.data.expenses.map(normalizeExpense)
      : [];
    return {
      ...(data?.data ?? {
        pay_period_no,
        pay_year,
        employee_email: email,
        is_approved: false,
        expenses: [],
        totals: { amount: 0, mileage: 0 },
      }),
      expenses: items,
    };
  } catch (err: any) {
    const status_code: number = err?.response?.status ?? 500;
    const data = err?.response?.data ?? {};
    throw new ExpensesApiError({
      status_code,
      error_code: data.error_code,
      message: data.message || data.error || err.message,
      context: data.context,
    });
  }
};

const resolveDateISO = (a?: ExpensePayload, b?: ExpensePayload): string => {
  const d = a?.date || b?.date;
  if(!d) throw new Error('date is required in payload');
  return d;
};

const makeBody = (obj: {
  old_expense?: ExpensePayload;
  new_expense?: ExpensePayload;
}) => obj;

const postUpsert = async (email: string, date: string, body: {
  old_expense?: ExpensePayload;
  new_expense?: ExpensePayload;
}): Promise<UpsertExpenseResult> => {
  
  try {
    const url = `/expenses/upsert/${encodeURIComponent(email)}/${date}`;
    const { data } = await api.post<UpsertExpenseResult>(url, body, { 
        headers: { 'Content-Type': 'application/json'},
      });
      return data;
  } catch(err:any) {
    const status_code: number = err?.response?.status ?? 500;
    const data = err?.response?.data ?? {};
    throw new ExpensesApiError({
      status_code,
      error_code: data.error_code,
      message: data.message || data.error || err.message,
      context: data.context,
    });
  }
};

//create a new expense
export const createExpenseByDate = async ( email: string, payload: ExpensePayload): Promise<UpsertExpenseResult> => {
  const new_expense = normalizePayload(payload);
  const date = resolveDateISO(new_expense);
  return postUpsert(email, date, makeBody({ new_expense: new_expense }));
};

//update an expense
export const updateExpenseByDate = async ( email: string, old_expense: ExpensePayload, new_expense: ExpensePayload): Promise<UpsertExpenseResult> => {
  const old_exp = normalizePayload(old_expense);
  const new_exp = normalizePayload(new_expense);
  const date = resolveDateISO(new_exp, old_exp);
  return postUpsert(email, date, makeBody({ old_expense: old_exp,new_expense: new_exp }));
};

//delete an expense
export const deleteExpenseByDate = async (email: string, old_expense: ExpensePayload): Promise<UpsertExpenseResult> => {
  const old = normalizePayload(old_expense);
  const date = resolveDateISO(undefined, old);
  return postUpsert(email, date, makeBody({ old_expense: old }));
};