import FinancialCalendar, {
  getDaysInBaseMonth,
} from "../../../../islands/FinancialCalendar.tsx";
import { define } from "../../../../utils.ts";
import {
  getIncomesByUser,
  getObligationsByUser,
  Income,
  Obligation,
} from "../../../../services/financhalServices.ts";
import {
  getFinancialBalancesByUser,
  upsertFinancialBalance,
} from "../../../../services/userService.ts";
import { page } from "fresh";
import {
  getDate,
  getMonth,
  getYear,
  MakeNewDate,
} from "../../../../helpers.ts";
import { createPublicId } from "../../../../helpers.ts";
import { SessionCookie } from "../../../auth/callback.ts";

// Helper function to generate recurring income entries
function generateRecurringIncomes(
  incomes: Income[],
  targetYear: number,
  targetMonth: number,
): Income[] {
  const result: Income[] = [];
  const baseMonth = targetMonth - 1;

  for (const income of incomes) {
    if (!income.frequency || !income.received_date) continue;

    let currentDate = MakeNewDate(income.received_date);
    let daysInMonth = getDaysInBaseMonth(
      getYear(currentDate),
      getMonth(currentDate),
    );

    while (
      (getYear(currentDate) === targetYear &&
        getMonth(currentDate) <= baseMonth) ||
      getYear(currentDate) < targetYear
    ) {
      if (getDate(currentDate) <= daysInMonth) {
        result.push({
          ...income,
          received_date: currentDate.getTime(),
        });
      }

      switch (income.frequency.toLowerCase()) {
        case "daily":
          currentDate = MakeNewDate(
            currentDate.getTime() + 24 * 60 * 60 * 1000,
          );
          break;
        case "biweekly":
          currentDate = MakeNewDate(
            currentDate.getTime() + 14 * 24 * 60 * 60 * 1000,
          );
          break;
        case "monthly":
          currentDate = MakeNewDate(
            currentDate.getTime() +
              getDaysInBaseMonth(
                  getYear(currentDate),
                  getMonth(currentDate),
                ) * 24 * 60 * 60 * 1000,
          );
          break;
        case "one-time":
          currentDate = MakeNewDate((targetYear + 2) + "-01-01");
          break;
        case "weekly":
          currentDate = MakeNewDate(
            currentDate.getTime() + 7 * 24 * 60 * 60 * 1000,
          );
          break;
        case "quarterly":
          currentDate = MakeNewDate(
            currentDate.getTime() +
              Number(
                  getDaysInBaseMonth(
                    getYear(currentDate),
                    getMonth(currentDate),
                  ),
                ) * 3 * 24 * 60 * 60 * 1000,
          );
          break;
        case "yearly":
        case "annually": {
          const monthNumber = getMonth(currentDate) + 1;
          const monthStr = monthNumber > 9 ? monthNumber : "0" + monthNumber;
          currentDate = MakeNewDate(
            (getYear(currentDate) + 1) + "-" + monthStr + "-" +
              getDate(currentDate),
          );
          break;
        }
        default:
          // Unknown frequency, skip to prevent infinite loop
          currentDate = MakeNewDate((targetYear + 2) + "-01-01");
          break;
      }

      daysInMonth = getDaysInBaseMonth(
        getYear(currentDate),
        getMonth(currentDate),
      );
    }
  }

  return result;
}

// Helper function to generate recurring obligation entries
function generateRecurringObligations(
  obligations: Obligation[],
  targetYear: number,
  targetMonth: number,
): Obligation[] {
  const result: Obligation[] = [];
  const baseMonth = targetMonth - 1;

  for (const obligation of obligations) {
    if (!obligation.frequency || !obligation.due_date) continue;

    let currentDate = MakeNewDate(obligation.due_date);
    let daysInMonth = getDaysInBaseMonth(
      getYear(currentDate),
      getMonth(currentDate),
    );

    while (
      (getYear(currentDate) === targetYear &&
        getMonth(currentDate) <= baseMonth) ||
      getYear(currentDate) < targetYear
    ) {
      if (getDate(currentDate) <= daysInMonth) {
        result.push({
          ...obligation,
          due_date: currentDate.getTime(),
        });
      }

      switch (obligation.frequency.toLowerCase()) {
        case "daily":
          currentDate = MakeNewDate(
            currentDate.getTime() + 24 * 60 * 60 * 1000,
          );
          break;
        case "biweekly":
          currentDate = MakeNewDate(
            currentDate.getTime() + 14 * 24 * 60 * 60 * 1000,
          );
          break;
        case "monthly":
          currentDate = MakeNewDate(
            currentDate.getTime() +
              getDaysInBaseMonth(
                  getYear(currentDate),
                  getMonth(currentDate),
                ) * 24 * 60 * 60 * 1000,
          );
          break;
        case "one-time":
          currentDate = MakeNewDate((targetYear + 2) + "-01-01");
          break;
        case "weekly":
          currentDate = MakeNewDate(
            currentDate.getTime() + 7 * 24 * 60 * 60 * 1000,
          );
          break;
        case "quarterly":
          currentDate = MakeNewDate(
            currentDate.getTime() +
              Number(
                  getDaysInBaseMonth(
                    getYear(currentDate),
                    getMonth(currentDate),
                  ),
                ) * 3 * 24 * 60 * 60 * 1000,
          );
          break;
        case "yearly":
        case "annually": {
          const monthNumber = getMonth(currentDate) + 1;
          const monthStr = monthNumber > 9 ? monthNumber : "0" + monthNumber;
          currentDate = MakeNewDate(
            (getYear(currentDate) + 1) + "-" + monthStr + "-" +
              getDate(currentDate),
          );
          break;
        }
        default:
          // Unknown frequency, skip to prevent infinite loop
          currentDate = MakeNewDate((targetYear + 2) + "-01-01");
          break;
      }

      daysInMonth = getDaysInBaseMonth(
        getYear(currentDate),
        getMonth(currentDate),
      );
    }
  }

  return result;
}

export const handler = define.handlers({
  GET: async (ctx) => {
    const params = ctx.params;
    let yearNum = parseInt(params.year, 10);
    let monthNum = parseInt(params.month, 10);
    if (isNaN(yearNum) || isNaN(monthNum)) {
      const fallback = `/calendar/financial-calendar/${getYear(new Date())}/${
        getMonth(new Date()) + 1
      }`;
      return new Response(null, {
        status: 302,
        headers: { Location: fallback },
      });
    }
    if (yearNum < 1900 || yearNum > 2100 || monthNum < 1 || monthNum > 12) {
      yearNum = getYear(new Date());
      monthNum = getMonth(new Date()) + 1;
    }

    const state = ctx.state;
    const stateData: SessionCookie = state.data;
    const publicId = stateData?.user_id
      ? await createPublicId(stateData.user_id)
      : "";
    const isEncrypted = stateData?.user_encrypted;
    let obligations: Obligation[] = [];
    let incomes: Income[] = [];
    let balance: number | null;
    let date: number | null = null;

    if (stateData?.user_id) {
      const rawObligations = await getObligationsByUser(stateData.user_id) ??
        [];
      const filteredObligations = rawObligations.filter((ob) =>
        ob.id && ob.user_id &&
        ob.frequency && ob.due_date && ob.created_on &&
        ob.updated_on
      );
      const rawIncomes = await getIncomesByUser(stateData.user_id) ?? [];
      const filteredIncomes = rawIncomes.filter((inc) =>
        inc.id && inc.user_id &&
        inc.frequency && inc.received_date && inc.created_on &&
        inc.updated_on
      );

      obligations = generateRecurringObligations(
        filteredObligations,
        yearNum,
        monthNum,
      );
      incomes = generateRecurringIncomes(filteredIncomes, yearNum, monthNum);
      const financialBalances = await getFinancialBalancesByUser(
        stateData.user_id,
      );
      if (financialBalances) {
        const latestBalance = financialBalances;
        balance = latestBalance.balance;
        date = latestBalance.balance_date;
      }
    }
    return page({
      stateData,
      obligations,
      incomes,
      params,
      yearNum,
      monthNum,
      balance: balance!,
      date: date ? new Date(date).toISOString().slice(0, 10) : null,
      publicId,
      isEncrypted,
      urlRoute: `/calendar/financial-calendar/${yearNum}/${monthNum}`,
      stateId: state.stateId,
    });
  },
  POST: async (ctx) => {
    const params = ctx.params;
    const formData = await ctx.req.formData();
    let balance: number | null = formData.get("balance")
      ? Number(formData.get("balance"))
      : null;
    let date: number | null = formData.get("date")
      ? Date.parse(formData.get("date") as string)
      : null;

    let yearNum = parseInt(params.year, 10);
    let monthNum = parseInt(params.month, 10);
    if (isNaN(yearNum) || isNaN(monthNum)) {
      const fallback = `/calendar/financial-calendar/${getYear(new Date())}/${
        getMonth(new Date()) + 1
      }`;
      return new Response(null, {
        status: 302,
        headers: { Location: fallback },
      });
    }
    if (yearNum < 1900 || yearNum > 2100 || monthNum < 1 || monthNum > 12) {
      yearNum = getYear(new Date());
      monthNum = getMonth(new Date()) + 1;
    }
    console.log("POST url", ctx.req.url);
    const state = ctx.state;
    const stateData: SessionCookie = state.data;
    const publicId = stateData?.user_id
      ? await createPublicId(stateData.user_id)
      : "";
    const isEncrypted = stateData?.user_encrypted;
    let obligations: Obligation[] = [];
    let incomes: Income[] = [];

    if (stateData?.user_id) {
      const rawObligations = await getObligationsByUser(stateData.user_id) ??
        [];
      const filteredObligations = rawObligations.filter((ob) =>
        ob.id && ob.user_id &&
        ob.frequency && ob.due_date && ob.created_on &&
        ob.updated_on
      );
      const rawIncomes = await getIncomesByUser(stateData.user_id) ?? [];
      const filteredIncomes = rawIncomes.filter((inc) =>
        inc.id && inc.user_id &&
        inc.frequency && inc.received_date && inc.created_on &&
        inc.updated_on
      );

      obligations = generateRecurringObligations(
        filteredObligations,
        yearNum,
        monthNum,
      );
      incomes = generateRecurringIncomes(filteredIncomes, yearNum, monthNum);
      console.log("obligations", obligations.length);
      console.log("incomes", incomes.length);
      if (!balance || !date) {
        const financialBalances = await getFinancialBalancesByUser(
          stateData.user_id,
        );
        if (financialBalances) {
          const latestBalance = financialBalances;
          if (!balance) {
            balance = latestBalance.balance ? latestBalance.balance : null;
          }
          if (!date) {
            date = latestBalance.balance_date
              ? latestBalance.balance_date
              : null;
          }
        }
      } else {
        const _updatedBalance = await upsertFinancialBalance(
          stateData.user_id,
          balance,
          date,
        );
      }
    }
    return page({
      stateData,
      obligations,
      incomes,
      params,
      yearNum,
      monthNum,
      balance,
      date: date ? new Date(date).toISOString().slice(0, 10) : null,
      publicId,
      isEncrypted,
      urlRoute: `/calendar/financial-calendar/${yearNum}/${monthNum}`,
      stateId: state.stateId,
    });
  },
});

export default define.page(
  (
    { data }: {
      data: {
        stateData: SessionCookie;
        obligations: Obligation[];
        incomes: Income[];
        yearNum: number;
        monthNum: number;
        balance?: string;
        date?: string;
        publicId: string;
        isEncrypted: boolean;
        urlRoute: string;
        stateId: string;
      };
    },
  ) => {
    return (
      <main class="calendar-route-shell">
        <div class="calendar-route-content">
          <FinancialCalendar
            obligations={data.obligations}
            incomes={data.incomes}
            yearNum={data.yearNum}
            monthNum={data.monthNum}
            oldBalance={data.balance}
            oldDate={data.date}
            userId={data.publicId}
          />
        </div>
      </main>
    );
  },
);