import Decimal from 'decimal.js';
import { InternalServerErrorException } from '@nestjs/common';
import type { StorefrontInvoicePaymentView } from '../../modules/storefrontCore/types/StorefrontInvoicePaymentView';
import type { StorefrontInvoiceView } from '../../modules/storefrontCore/types/StorefrontInvoiceView';
import type { CryptoAtomicConverter } from '../../types/CryptoAtomicConverter';
import type { Invoice } from '../../modules/payment/entities/Invoice';
import type { InvoicePayment } from '../../modules/payment/entities/InvoicePayment';
import { PaymentMethod } from '../../modules/payment/types/PaymentMethod';
import dayjs from '../../plugins/dayjs';
import { generateQrCodeDataUrl } from '../generateQrCodeDataUrl';
import { convertBtcAtomicToBtc } from '../bitcoin/convertBtcAtomicToBtc';
import { convertXmrAtomicToXmr } from '../monero/convertXmrAtomicToXmr';
import { subtractAtomic } from '../atomic/subtractAtomic';
import { paymentMethodLabel } from '../../consts/paymentMethodLabel';
import { deriveInvoiceState } from './deriveInvoiceState';
import { formatInvoicePaymentConfirmationStatus } from './formatInvoicePaymentConfirmationStatus';
import { resolveInvoiceStatusMessage } from './resolveInvoiceStatusMessage';
import { resolveInvoiceStatusVariant } from './resolveInvoiceStatusVariant';
import { resolveInvoiceRequiredConfirmations } from './resolveInvoiceRequiredConfirmations';
import { sumInvoicePaymentAmountsAtomic } from './sumInvoicePaymentAmountsAtomic';

export const toStorefrontInvoiceView = async (invoice: Invoice): Promise<StorefrontInvoiceView> => {
    switch (invoice.paymentMethod) {
        case PaymentMethod.Xmr:
            if (!invoice.moneroDetails) {
                throw new InternalServerErrorException('Invoice is missing Monero payment details');
            }

            return buildStorefrontInvoiceView({
                invoice,
                paymentLabel: paymentMethodLabel[PaymentMethod.Xmr],
                convertAtomicToCrypto: convertXmrAtomicToXmr,
                buildQrCodePayload: (paymentAddress, amountCrypto) =>
                    `monero:${paymentAddress}?tx_amount=${amountCrypto}`
            });
        case PaymentMethod.Btc:
            if (!invoice.btcDetails) {
                throw new InternalServerErrorException('Invoice is missing Bitcoin payment details');
            }

            return buildStorefrontInvoiceView({
                invoice,
                paymentLabel: paymentMethodLabel[PaymentMethod.Btc],
                convertAtomicToCrypto: convertBtcAtomicToBtc,
                buildQrCodePayload: (paymentAddress, amountCrypto) => `bitcoin:${paymentAddress}?amount=${amountCrypto}`
            });
        default:
            throw new InternalServerErrorException(`Unsupported payment method: ${String(invoice.paymentMethod)}`);
    }
};

const buildStorefrontInvoiceView = async ({
    invoice,
    paymentLabel,
    convertAtomicToCrypto,
    buildQrCodePayload
}: {
    invoice: Invoice;
    paymentLabel: string;
    convertAtomicToCrypto: CryptoAtomicConverter;
    buildQrCodePayload: (paymentAddress: string, amountCrypto: string) => string;
}): Promise<StorefrontInvoiceView> => {
    const invoiceState = deriveInvoiceState(invoice);

    const {
        isAwaitingPayment,
        isUnderpaid,
        isPaidSufficient,
        isPaidAwaitingConfirmations,
        isPaidAndConfirmed,
        isExpired,
        hasPendingConfirmations
    } = invoiceState;

    const expectedTotalCrypto = convertAtomicToCrypto(invoice.expectedTotalAtomic);
    const receivedAtomic = sumInvoicePaymentAmountsAtomic(invoice.payments);
    const receivedTotalCrypto = receivedAtomic === '0' ? null : convertAtomicToCrypto(receivedAtomic);

    const requiredConfirmations = resolveInvoiceRequiredConfirmations(invoice);

    const payments = [...(invoice.payments ?? [])]
        .sort((left, right) => left.createdAt.getTime() - right.createdAt.getTime())
        .map(payment => toPaymentView(payment, requiredConfirmations, convertAtomicToCrypto));

    const showPaymentCapture = (isAwaitingPayment || isUnderpaid) && !isExpired;

    const expiresInDuration = showPaymentCapture ? formatInvoiceExpiresInDuration(invoice.expiresAt) : null;

    let instructionPrefix: string | null = null;
    let instructionAmountCrypto: string | null = null;
    let instructionSuffix: string | null = null;
    let qrCodeUrl: string | null = null;

    if (showPaymentCapture) {
        if (isAwaitingPayment) {
            instructionAmountCrypto = expectedTotalCrypto;
            instructionPrefix = 'Send exactly';
            instructionSuffix = 'to the address below.';
        } else {
            const remainingTotalCryptoAtomic = subtractAtomic(invoice.expectedTotalAtomic, receivedAtomic);

            instructionAmountCrypto = convertAtomicToCrypto(remainingTotalCryptoAtomic, Decimal.ROUND_CEIL);
            instructionPrefix = 'Send';
            instructionSuffix = 'more to the same address below.';
        }

        const qrCodePayload = buildQrCodePayload(invoice.paymentAddress, instructionAmountCrypto);

        qrCodeUrl = await generateQrCodeDataUrl(qrCodePayload);
    }

    const statusMessage = resolveInvoiceStatusMessage(invoiceState);

    const statusVariant = resolveInvoiceStatusVariant(invoiceState);

    return {
        paymentLabel,
        expectedTotalCrypto,
        receivedTotalCrypto,
        paymentAddress: invoice.paymentAddress,
        qrCodeUrl,
        instructionPrefix,
        instructionAmountCrypto,
        instructionSuffix,
        expiresInDuration,
        payments,
        isPaidSufficient,
        showStatusMessage: statusMessage !== null,
        statusMessage,
        statusVariant,
        showProminentAmount: showPaymentCapture && isAwaitingPayment,
        showExpectedTotal:
            isPaidAwaitingConfirmations || isPaidAndConfirmed || (isExpired && (isAwaitingPayment || isUnderpaid)),
        showReceivedTotal: isUnderpaid || isPaidAwaitingConfirmations || isPaidAndConfirmed,
        showInstruction: showPaymentCapture,
        showExpiry: showPaymentCapture,
        showQr: showPaymentCapture,
        showAddress: showPaymentCapture,
        showPayments: (isUnderpaid || isPaidAwaitingConfirmations) && payments.length > 0,
        showRefresh: resolveShowRefresh({
            isExpired,
            isAwaitingPayment,
            isUnderpaid,
            isPaidAwaitingConfirmations,
            isPaidAndConfirmed,
            hasPendingConfirmations
        })
    };
};

const toPaymentView = (
    payment: InvoicePayment,
    requiredConfirmations: number,
    convertAtomicToCrypto: CryptoAtomicConverter
): StorefrontInvoicePaymentView => {
    const isConfirmed = payment.confirmations >= requiredConfirmations;

    return {
        txHash: payment.txHash,
        amountCrypto: convertAtomicToCrypto(payment.amountAtomic),
        confirmationStatus: formatInvoicePaymentConfirmationStatus({
            confirmations: payment.confirmations,
            requiredConfirmations,
            createdAt: payment.createdAt,
            format: 'extended'
        }),
        confirmationStatusVariant: isConfirmed ? 'confirmed' : 'confirming'
    };
};

const resolveShowRefresh = ({
    isExpired,
    isAwaitingPayment,
    isUnderpaid,
    isPaidAwaitingConfirmations,
    isPaidAndConfirmed,
    hasPendingConfirmations
}: {
    isExpired: boolean;
    isAwaitingPayment: boolean;
    isUnderpaid: boolean;
    isPaidAwaitingConfirmations: boolean;
    isPaidAndConfirmed: boolean;
    hasPendingConfirmations: boolean;
}): boolean => {
    if (isPaidAndConfirmed) {
        return false;
    }

    if (isPaidAwaitingConfirmations) {
        return true;
    }

    if (isExpired && isAwaitingPayment) {
        return false;
    }

    if (isExpired && isUnderpaid) {
        return hasPendingConfirmations;
    }

    return isAwaitingPayment || isUnderpaid;
};

const formatInvoiceExpiresInDuration = (expiresAt: Date): string => {
    const totalSeconds = Math.max(0, dayjs(expiresAt).diff(dayjs(), 'second'));

    const days = Math.floor(totalSeconds / 86_400);
    const hours = Math.floor((totalSeconds % 86_400) / 3_600);
    const minutes = Math.floor((totalSeconds % 3_600) / 60);
    const seconds = totalSeconds % 60;

    const parts: string[] = [];

    if (days > 0) {
        parts.push(`${days} ${days === 1 ? 'day' : 'days'}`);
    }

    if (hours > 0) {
        parts.push(`${hours} ${hours === 1 ? 'hour' : 'hours'}`);
    }

    if (minutes > 0) {
        parts.push(`${minutes} ${minutes === 1 ? 'minute' : 'minutes'}`);
    }

    if (seconds > 0) {
        parts.push(`${seconds} ${seconds === 1 ? 'second' : 'seconds'}`);
    }

    if (parts.length === 0) {
        return '0 seconds';
    }

    return parts.slice(0, 2).join(' and ');
};