"use client";
import { Paper, Select, Title, Button, Text, Grid, ScrollArea, Table, Divider, Center, Loader, Stack, Group } from "@mantine/core";
import { DateInput } from '@mantine/dates';
import { useEffect, useRef, useState } from "react";
import { useSearchParams } from "next/navigation";
import { notifications } from "@mantine/notifications";
import dayjs from 'dayjs';
import { IconFileSpreadsheet, IconFileText, IconFileTypePdf } from "@tabler/icons-react";
import { generatePDF } from "@/app/_components/statement_download/PdfGenerator";
import { generateCSV } from "@/app/_components/statement_download/CsvGenerator";

export default function AccountStatementPage() {

    const pdfRef = useRef<HTMLDivElement>(null);
    const [accountOptions, setAccountOptions] = useState<{ value: string; label: string }[]>([]);
    const [selectedAccNo, setSelectedAccNo] = useState<string | null>(null);
    const [startDate, setStartDate] = useState<Date | null>(null);
    const [endDate, setEndDate] = useState<Date | null>(null);
    const [transactions, setTransactions] = useState<any[]>([]);
    const searchParams = useSearchParams();
    const passedAccNo = searchParams.get("accNo");
    const [loading, setLoading] = useState(false);
    const [availableBalance, setAvailableBalance] = useState<string | null>(null);

    useEffect(() => {
        const saved = sessionStorage.getItem("accountData");
        if (saved) {
            const parsed = JSON.parse(saved);
            const options = parsed.map((acc: any) => ({
                label: `${acc.stAccountNo} - ${acc.stAccountType}`,
                value: acc.stAccountNo,
            }));
            setAccountOptions(options);

            if (passedAccNo) {
                setSelectedAccNo(passedAccNo);
                //Automatically fetch last 5 transactions if accNo is passed
                const token = localStorage.getItem("access_token");
                setLoading(true);
                fetch(`/api/transactions/account/${passedAccNo}`, {
                    method: "GET",
                    headers: {
                        "Content-Type": "application/json",
                        Authorization: `Bearer ${token}`,
                    },
                })
                    .then(res => res.json())
                    .then(data => {
                        if (Array.isArray(data)) {
                            const last5 = data.slice(0, 5);
                            setTransactions(last5);
                            // Reuse balance logic
                            const saved = sessionStorage.getItem("accountData");
                            if (saved) {
                                const parsed = JSON.parse(saved);
                                const acc = parsed.find((a: any) => a.stAccountNo === passedAccNo);
                                if (acc) {
                                    setAvailableBalance(acc.stAvailableBalance);
                                }
                            }
                        }
                    })
                    .catch(() => {
                        notifications.show({
                            withBorder: true,
                            color: "red",
                            title: "Fetch Failed",
                            message: "Could not load recent transactions.",
                            autoClose: 5000,
                        });
                    })
                    .finally(() => setLoading(false));
            }
        }
    }, [passedAccNo]);

    const handleAccountTransaction = async () => {
        if (!selectedAccNo || !startDate || !endDate) {
            notifications.show({
                withBorder: true,
                color: "red",
                title: "Missing field",
                message: "Please select Account number,Start date and End date",
                autoClose: 5000,
            });
            return;
        }
        const start = dayjs(startDate);
        const end = dayjs(endDate);
        const today = dayjs().startOf('day');
        if (end.isAfter(today)) {
            notifications.show({
                withBorder: true,
                color: "red",
                title: "Invalid End Date",
                message: "End date can not be the future date.",
                autoClose: 4000,
            });
            return;
        }
        if (start.isAfter(end)) {
            notifications.show({
                withBorder: true,
                color: "red",
                title: "Invalid Start Date",
                message: "Start date can not be less than end date",
                autoClose: 4000,
            });
            return;
        }
        if (end.diff(start, "day") > 90) {
            notifications.show({
                withBorder: true,
                color: "red",
                title: "Invalid Date range",
                message: "End date must be within 90 days from start date",
                autoClose: 4000,
            });
            return;
        }
        try {
            const token = localStorage.getItem("access_token");
            setLoading(true);
            const response = await fetch(`/api/transactions/account/${selectedAccNo}?fromDate=${dayjs(start).format('DDMMYYYY')}&toDate=${dayjs(end).format('DDMMYYYY')}`,
                {
                    method: "GET",
                    headers: {
                        "Content-Type": "application/json",
                        Authorization: `Bearer ${token}`,
                    },
                });
            const data = await response.json();
            if (response.ok && Array.isArray(data)) {
                setTransactions(data.reverse());
                // SHowing Available balance
                const saved = sessionStorage.getItem("accountData");
                if (saved) {
                    const parsed = JSON.parse(saved);
                    const acc = parsed.find((a: any) => a.stAccountNo === selectedAccNo);
                    if (acc) {
                        setAvailableBalance(acc.stAvailableBalance);
                    }
                }
            }
        } catch {
            notifications.show({
                withBorder: true,
                color: "red",
                title: "Please try again later",
                message: "Unable to Fetch Account Transaction, Please try again later",
                autoClose: 5000,
            });
        }
        finally {
            setLoading(false);
        }
    };
    const cellStyle = {
        border: "1px solid #ccc",
        padding: "8px",
    };

    return (
        <Grid gutter="md">
            {/* Left side – form */}
            <Grid.Col span={{ base: 12, md: 4 }}>
                <Paper shadow="sm" radius="md" p="md" withBorder h={400}>
                    <Title order={4} mb="sm">Account Transactions</Title>
                    <Select
                        label="Select Account Number"
                        placeholder="Choose account number"
                        data={accountOptions}
                        value={selectedAccNo}
                        onChange={setSelectedAccNo}
                        searchable
                    />
                    <DateInput
                        label="Start Date"
                        value={startDate}
                        onChange={setStartDate}
                        placeholder="Enter start date"
                    />
                    <DateInput
                        label="End Date"
                        value={endDate}
                        onChange={setEndDate}
                        placeholder="Enter end date"
                    />
                    <Button fullWidth mt="md" onClick={handleAccountTransaction}>
                        Proceed
                    </Button>
                </Paper>
            </Grid.Col>

            {/* Right side – transaction list */}
            <Grid.Col span={{ base: 12, md: 8 }}>
                <Paper shadow="sm" radius="md" p="md" withBorder h={400} style={{ display: 'flex', flexDirection: 'column' }}>
                    <Title order={5} mb="xs">Account Transactions</Title>
                    <Group justify="space-between" align="center" mt="sm">
                        <div>
                            <Text fw={500} ><strong>Account No :</strong> {selectedAccNo}</Text>
                            {availableBalance && (
                                <Text fw={500} >
                                    <strong>Available Balance :</strong> ₹ {parseFloat(availableBalance).toLocaleString("en-IN", {
                                        minimumFractionDigits: 2,
                                    })}
                                </Text>
                            )}
                        </div>

                        <Group gap="xs">
                            <Text>Download :</Text>
                            {/* <IconFileTypePdf size={22} style={{ cursor: "pointer" }} onClick={() => console.log("Download PDF")} /> */}
                            <IconFileTypePdf
                                size={22}
                                style={{ cursor: "pointer" }}
                                onClick={() =>
                                    generatePDF(selectedAccNo || "", availableBalance || "0", transactions,
                                        localStorage.getItem("remitter_name") || "",
                                        startDate ? dayjs(startDate).format("DD/MM/YYYY") : "",
                                        endDate ? dayjs(endDate).format("DD/MM/YYYY") : "")
                                }
                            />
                            <IconFileSpreadsheet
                                size={22}
                                style={{ cursor: "pointer" }}
                                onClick={() =>
                                    generateCSV(selectedAccNo || "NA", availableBalance || "0.00", transactions)
                                }
                            />

                        </Group>
                    </Group>

                    <Divider size="xs" />
                    <ScrollArea style={{ flex: 1 }}>
                        {loading ? (

                            <Center h="100%">
                                <Stack align="center" gap="sm">
                                    <Loader size="lg" color="cyan" type="bars" />
                                    <Text>Please wait, details are being fetched .....</Text>
                                </Stack>
                            </Center>
                        ) : transactions.length === 0 ? (
                            <p>No transactions found.</p>
                        ) : (
                            <>
                                <Text fs="italic" c='#228be6' ta='center'>
                                    {!startDate && !endDate ? 'Last 5 Transactions'
                                        : startDate && endDate ? `Transactions from ${dayjs(startDate).format("DD/MM/YYYY")} to ${dayjs(endDate).format("DD/MM/YYYY")}`
                                            : ""}
                                </Text>
                                <Table style={{ borderCollapse: "collapse", width: '100%' }}>
                                    <thead style={{ backgroundColor: "#3385ff" }}>
                                        {/* <tr>
                                            <th style={{ ...cellStyle, position: 'sticky', textAlign: "left" }}>Name</th>
                                            <th style={{ ...cellStyle, position: 'sticky', textAlign: "left" }}>Date</th>
                                            <th style={{ ...cellStyle, position: 'sticky', textAlign: "left" }}>Type</th>
                                            <th style={{ ...cellStyle, position: 'sticky', textAlign: "left" }}>Amount(₹)</th>
                                            <th style={{ ...cellStyle, position: 'sticky', textAlign: "left" }}>Available Balance(₹)</th>
                                        </tr> */}
                                    </thead>
                                    <tbody style={{ maxHeight: '250px', overflowY: 'auto', width: '100%' }}>
                                        {transactions.map((txn, i) => (
                                            <tr key={i}>
                                                <td style={{ ...cellStyle, textAlign: "left" }}>  {txn.name || "—"}</td>
                                                <td style={{ ...cellStyle, textAlign: "left" }}>{txn.date || "—"}</td>
                                                {/* <td style={{ ...cellStyle, textAlign: "left" }}>{txn.type}</td> */}
                                                <td style={{ ...cellStyle, textAlign: "right", color: txn.type === "DR" ? "#e03131" : "#2f9e44" }}>
                                                    {parseFloat(txn.amount).toLocaleString("en-IN", {
                                                        minimumFractionDigits: 2,
                                                    })} <span style={{ fontSize: '10px' }}>{txn.type === "DR" ? "Dr." : "Cr."}</span>
                                                </td>
                                                <td style={{ ...cellStyle, textAlign: "right", color: "blue", fontSize: '12px' }}>₹{txn.balance || "—"}</td>
                                            </tr>
                                        ))}
                                    </tbody>
                                </Table>
                            </>
                        )}
                    </ScrollArea>
                </Paper>
            </Grid.Col >
        </Grid >
    );
}