/*
 This file is part of GNU Taler
 (C) 2019 Taler Systems S.A.

 GNU Taler is free software; you can redistribute it and/or modify it under the
 terms of the GNU General Public License as published by the Free Software
 Foundation; either version 3, or (at your option) any later version.

 GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

 You should have received a copy of the GNU General Public License along with
 GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */

/**
 * Imports.
 */
import {
  AmountJson,
  Amounts, OrderShortInfo, PaymentStatus, timestampCmp, Transaction, TransactionsRequest,
  TransactionsResponse, TransactionType, WithdrawalDetails, WithdrawalType
} from "@gnu-taler/taler-util";
import { InternalWalletState } from "../common.js";
import {
  AbortStatus, RefundState, ReserveRecord, ReserveRecordStatus, WalletRefundItem
} from "../db.js";
import { processDepositGroup } from "./deposits.js";
import { getExchangeDetails } from "./exchanges.js";
import { processPurchasePay } from "./pay.js";
import { processRefreshGroup } from "./refresh.js";
import { getFundingPaytoUris } from "./reserves.js";
import { processTip } from "./tip.js";
import { processWithdrawGroup } from "./withdraw.js";

/**
 * Create an event ID from the type and the primary key for the event.
 */
export function makeEventId(
  type: TransactionType | TombstoneTag,
  ...args: string[]
): string {
  return type + ":" + args.map((x) => encodeURIComponent(x)).join(":");
}

function shouldSkipCurrency(
  transactionsRequest: TransactionsRequest | undefined,
  currency: string,
): boolean {
  if (!transactionsRequest?.currency) {
    return false;
  }
  return transactionsRequest.currency.toLowerCase() !== currency.toLowerCase();
}

function shouldSkipSearch(
  transactionsRequest: TransactionsRequest | undefined,
  fields: string[],
): boolean {
  if (!transactionsRequest?.search) {
    return false;
  }
  const needle = transactionsRequest.search.trim();
  for (const f of fields) {
    if (f.indexOf(needle) >= 0) {
      return false;
    }
  }
  return true;
}

/**
 * Retrieve the full event history for this wallet.
 */
export async function getTransactions(
  ws: InternalWalletState,
  transactionsRequest?: TransactionsRequest,
): Promise<TransactionsResponse> {
  const transactions: Transaction[] = [];

  await ws.db
    .mktx((x) => ({
      coins: x.coins,
      denominations: x.denominations,
      exchanges: x.exchanges,
      exchangeDetails: x.exchangeDetails,
      proposals: x.proposals,
      purchases: x.purchases,
      refreshGroups: x.refreshGroups,
      reserves: x.reserves,
      tips: x.tips,
      withdrawalGroups: x.withdrawalGroups,
      planchets: x.planchets,
      recoupGroups: x.recoupGroups,
      depositGroups: x.depositGroups,
      tombstones: x.tombstones,
    }))
    .runReadOnly(
      // Report withdrawals that are currently in progress.
      async (tx) => {
        tx.withdrawalGroups.iter().forEachAsync(async (wsr) => {
          if (
            shouldSkipCurrency(
              transactionsRequest,
              wsr.rawWithdrawalAmount.currency,
            )
          ) {
            return;
          }

          if (shouldSkipSearch(transactionsRequest, [])) {
            return;
          }

          const r = await tx.reserves.get(wsr.reservePub);
          if (!r) {
            return;
          }
          let amountRaw: AmountJson | undefined = undefined;
          if (wsr.withdrawalGroupId === r.initialWithdrawalGroupId) {
            amountRaw = r.instructedAmount;
          } else {
            amountRaw = wsr.denomsSel.totalWithdrawCost;
          }
          let withdrawalDetails: WithdrawalDetails;
          if (r.bankInfo) {
            withdrawalDetails = {
              type: WithdrawalType.TalerBankIntegrationApi,
              confirmed: true,
              reservePub: wsr.reservePub,
              bankConfirmationUrl: r.bankInfo.confirmUrl,
            };
          } else {
            const exchangeDetails = await getExchangeDetails(
              tx,
              wsr.exchangeBaseUrl,
            );
            if (!exchangeDetails) {
              // FIXME: report somehow
              return;
            }
            withdrawalDetails = {
              type: WithdrawalType.ManualTransfer,
              reservePub: wsr.reservePub,
              exchangePaytoUris:
                exchangeDetails.wireInfo?.accounts.map((x) => x.payto_uri) ??
                [],
            };
          }

          transactions.push({
            type: TransactionType.Withdrawal,
            amountEffective: Amounts.stringify(wsr.denomsSel.totalCoinValue),
            amountRaw: Amounts.stringify(amountRaw),
            withdrawalDetails,
            exchangeBaseUrl: wsr.exchangeBaseUrl,
            pending: !wsr.timestampFinish,
            timestamp: wsr.timestampStart,
            transactionId: makeEventId(
              TransactionType.Withdrawal,
              wsr.withdrawalGroupId,
            ),
            frozen: false,
            ...(wsr.lastError ? { error: wsr.lastError } : {}),
          });
        });

        // Report pending withdrawals based on reserves that
        // were created, but where the actual withdrawal group has
        // not started yet.
        tx.reserves.iter().forEachAsync(async (r) => {
          if (shouldSkipCurrency(transactionsRequest, r.currency)) {
            return;
          }
          if (shouldSkipSearch(transactionsRequest, [])) {
            return;
          }
          if (r.initialWithdrawalStarted) {
            return;
          }
          if (r.reserveStatus === ReserveRecordStatus.BANK_ABORTED) {
            return;
          }
          let withdrawalDetails: WithdrawalDetails;
          if (r.bankInfo) {
            withdrawalDetails = {
              type: WithdrawalType.TalerBankIntegrationApi,
              confirmed: false,
              reservePub: r.reservePub,
              bankConfirmationUrl: r.bankInfo.confirmUrl,
            };
          } else {
            withdrawalDetails = {
              type: WithdrawalType.ManualTransfer,
              reservePub: r.reservePub,
              exchangePaytoUris: await getFundingPaytoUris(tx, r.reservePub),
            };
          }
          transactions.push({
            type: TransactionType.Withdrawal,
            amountRaw: Amounts.stringify(r.instructedAmount),
            amountEffective: Amounts.stringify(
              r.initialDenomSel.totalCoinValue,
            ),
            exchangeBaseUrl: r.exchangeBaseUrl,
            pending: true,
            timestamp: r.timestampCreated,
            withdrawalDetails: withdrawalDetails,
            transactionId: makeEventId(
              TransactionType.Withdrawal,
              r.initialWithdrawalGroupId,
            ),
            frozen: false,
            ...(r.lastError ? { error: r.lastError } : {}),
          });
        });

        tx.depositGroups.iter().forEachAsync(async (dg) => {
          const amount = Amounts.parseOrThrow(dg.contractTermsRaw.amount);
          if (shouldSkipCurrency(transactionsRequest, amount.currency)) {
            return;
          }

          transactions.push({
            type: TransactionType.Deposit,
            amountRaw: Amounts.stringify(dg.effectiveDepositAmount),
            amountEffective: Amounts.stringify(dg.totalPayCost),
            pending: !dg.timestampFinished,
            frozen: false,
            timestamp: dg.timestampCreated,
            targetPaytoUri: dg.wire.payto_uri,
            transactionId: makeEventId(
              TransactionType.Deposit,
              dg.depositGroupId,
            ),
            depositGroupId: dg.depositGroupId,
            ...(dg.lastError ? { error: dg.lastError } : {}),
          });
        });

        tx.purchases.iter().forEachAsync(async (pr) => {
          if (
            shouldSkipCurrency(
              transactionsRequest,
              pr.download.contractData.amount.currency,
            )
          ) {
            return;
          }
          const contractData = pr.download.contractData;
          if (shouldSkipSearch(transactionsRequest, [contractData.summary])) {
            return;
          }
          const proposal = await tx.proposals.get(pr.proposalId);
          if (!proposal) {
            return;
          }
          const info: OrderShortInfo = {
            merchant: contractData.merchant,
            orderId: contractData.orderId,
            products: contractData.products,
            summary: contractData.summary,
            summary_i18n: contractData.summaryI18n,
            contractTermsHash: contractData.contractTermsHash,
          };
          if (contractData.fulfillmentUrl !== "") {
            info.fulfillmentUrl = contractData.fulfillmentUrl;
          }
          const paymentTransactionId = makeEventId(
            TransactionType.Payment,
            pr.proposalId,
          );
          const err = pr.lastPayError ?? pr.lastRefundStatusError;
          transactions.push({
            type: TransactionType.Payment,
            amountRaw: Amounts.stringify(contractData.amount),
            amountEffective: Amounts.stringify(pr.totalPayCost),
            status: pr.timestampFirstSuccessfulPay
              ? PaymentStatus.Paid
              : PaymentStatus.Accepted,
            pending:
              !pr.timestampFirstSuccessfulPay &&
              pr.abortStatus === AbortStatus.None,
            timestamp: pr.timestampAccept,
            transactionId: paymentTransactionId,
            proposalId: pr.proposalId,
            info: info,
            frozen: pr.payFrozen ?? false,
            ...(err ? { error: err } : {}),
          });

          const refundGroupKeys = new Set<string>();

          for (const rk of Object.keys(pr.refunds)) {
            const refund = pr.refunds[rk];
            const groupKey = `${refund.executionTime.t_ms}`;
            refundGroupKeys.add(groupKey);
          }

          for (const groupKey of refundGroupKeys.values()) {
            const refundTombstoneId = makeEventId(
              TombstoneTag.DeleteRefund,
              pr.proposalId,
              groupKey,
            );
            const tombstone = await tx.tombstones.get(refundTombstoneId);
            if (tombstone) {
              continue;
            }
            const refundTransactionId = makeEventId(
              TransactionType.Refund,
              pr.proposalId,
              groupKey,
            );
            let r0: WalletRefundItem | undefined;
            let amountRaw = Amounts.getZero(contractData.amount.currency);
            let amountEffective = Amounts.getZero(contractData.amount.currency);
            for (const rk of Object.keys(pr.refunds)) {
              const refund = pr.refunds[rk];
              const myGroupKey = `${refund.executionTime.t_ms}`;
              if (myGroupKey !== groupKey) {
                continue;
              }
              if (!r0) {
                r0 = refund;
              }

              if (refund.type === RefundState.Applied) {
                amountRaw = Amounts.add(amountRaw, refund.refundAmount).amount;
                amountEffective = Amounts.add(
                  amountEffective,
                  Amounts.sub(
                    refund.refundAmount,
                    refund.refundFee,
                    refund.totalRefreshCostBound,
                  ).amount,
                ).amount;
              }
            }
            if (!r0) {
              throw Error("invariant violated");
            }
            transactions.push({
              type: TransactionType.Refund,
              info,
              refundedTransactionId: paymentTransactionId,
              transactionId: refundTransactionId,
              timestamp: r0.obtainedTime,
              amountEffective: Amounts.stringify(amountEffective),
              amountRaw: Amounts.stringify(amountRaw),
              pending: false,
              frozen: false,
            });
          }
        });

        tx.tips.iter().forEachAsync(async (tipRecord) => {
          if (
            shouldSkipCurrency(
              transactionsRequest,
              tipRecord.tipAmountRaw.currency,
            )
          ) {
            return;
          }
          if (!tipRecord.acceptedTimestamp) {
            return;
          }
          transactions.push({
            type: TransactionType.Tip,
            amountEffective: Amounts.stringify(tipRecord.tipAmountEffective),
            amountRaw: Amounts.stringify(tipRecord.tipAmountRaw),
            pending: !tipRecord.pickedUpTimestamp,
            frozen: false,
            timestamp: tipRecord.acceptedTimestamp,
            transactionId: makeEventId(
              TransactionType.Tip,
              tipRecord.walletTipId,
            ),
            merchantBaseUrl: tipRecord.merchantBaseUrl,
            error: tipRecord.lastError,
          });
        });
      },
    );

  const txPending = transactions.filter((x) => x.pending);
  const txNotPending = transactions.filter((x) => !x.pending);

  txPending.sort((h1, h2) => timestampCmp(h1.timestamp, h2.timestamp));
  txNotPending.sort((h1, h2) => timestampCmp(h1.timestamp, h2.timestamp));

  return { transactions: [...txNotPending, ...txPending] };
}

export enum TombstoneTag {
  DeleteWithdrawalGroup = "delete-withdrawal-group",
  DeleteReserve = "delete-reserve",
  DeletePayment = "delete-payment",
  DeleteTip = "delete-tip",
  DeleteRefreshGroup = "delete-refresh-group",
  DeleteDepositGroup = "delete-deposit-group",
  DeleteRefund = "delete-refund",
}

export async function retryTransactionNow(
  ws: InternalWalletState,
  transactionId: string,
): Promise<void> {
  const [type, ...rest] = transactionId.split(":");
}

/**
 * Immediately retry the underlying operation
 * of a transaction.
 */
export async function retryTransaction(
  ws: InternalWalletState,
  transactionId: string,
): Promise<void> {
  const [type, ...rest] = transactionId.split(":");

  switch (type) {
    case TransactionType.Deposit:
      const depositGroupId = rest[0];
      processDepositGroup(ws, depositGroupId, true);
      break;
    case TransactionType.Withdrawal:
      const withdrawalGroupId = rest[0];
      await processWithdrawGroup(ws, withdrawalGroupId, true);
      break;
    case TransactionType.Payment:
      const proposalId = rest[0];
      await processPurchasePay(ws, proposalId, true);
      break;
    case TransactionType.Tip:
      const walletTipId = rest[0];
      await processTip(ws, walletTipId, true);
      break;
    case TransactionType.Refresh:
      const refreshGroupId = rest[0];
      await processRefreshGroup(ws, refreshGroupId, true);
      break;
    default:
      break;
  }
}

/**
 * Permanently delete a transaction based on the transaction ID.
 */
export async function deleteTransaction(
  ws: InternalWalletState,
  transactionId: string,
): Promise<void> {
  const [type, ...rest] = transactionId.split(":");

  if (type === TransactionType.Withdrawal) {
    const withdrawalGroupId = rest[0];
    await ws.db
      .mktx((x) => ({
        withdrawalGroups: x.withdrawalGroups,
        reserves: x.reserves,
        tombstones: x.tombstones,
      }))
      .runReadWrite(async (tx) => {
        const withdrawalGroupRecord = await tx.withdrawalGroups.get(
          withdrawalGroupId,
        );
        if (withdrawalGroupRecord) {
          await tx.withdrawalGroups.delete(withdrawalGroupId);
          await tx.tombstones.put({
            id: TombstoneTag.DeleteWithdrawalGroup + ":" + withdrawalGroupId,
          });
          return;
        }
        const reserveRecord:
          | ReserveRecord
          | undefined = await tx.reserves.indexes.byInitialWithdrawalGroupId.get(
            withdrawalGroupId,
          );
        if (reserveRecord && !reserveRecord.initialWithdrawalStarted) {
          const reservePub = reserveRecord.reservePub;
          await tx.reserves.delete(reservePub);
          await tx.tombstones.put({
            id: TombstoneTag.DeleteReserve + ":" + reservePub,
          });
        }
      });
  } else if (type === TransactionType.Payment) {
    const proposalId = rest[0];
    await ws.db
      .mktx((x) => ({
        proposals: x.proposals,
        purchases: x.purchases,
        tombstones: x.tombstones,
      }))
      .runReadWrite(async (tx) => {
        let found = false;
        const proposal = await tx.proposals.get(proposalId);
        if (proposal) {
          found = true;
          await tx.proposals.delete(proposalId);
        }
        const purchase = await tx.purchases.get(proposalId);
        if (purchase) {
          found = true;
          await tx.purchases.delete(proposalId);
        }
        if (found) {
          await tx.tombstones.put({
            id: TombstoneTag.DeletePayment + ":" + proposalId,
          });
        }
      });
  } else if (type === TransactionType.Refresh) {
    const refreshGroupId = rest[0];
    await ws.db
      .mktx((x) => ({
        refreshGroups: x.refreshGroups,
        tombstones: x.tombstones,
      }))
      .runReadWrite(async (tx) => {
        const rg = await tx.refreshGroups.get(refreshGroupId);
        if (rg) {
          await tx.refreshGroups.delete(refreshGroupId);
          await tx.tombstones.put({
            id: TombstoneTag.DeleteRefreshGroup + ":" + refreshGroupId,
          });
        }
      });
  } else if (type === TransactionType.Tip) {
    const tipId = rest[0];
    await ws.db
      .mktx((x) => ({
        tips: x.tips,
        tombstones: x.tombstones,
      }))
      .runReadWrite(async (tx) => {
        const tipRecord = await tx.tips.get(tipId);
        if (tipRecord) {
          await tx.tips.delete(tipId);
          await tx.tombstones.put({
            id: TombstoneTag.DeleteTip + ":" + tipId,
          });
        }
      });
  } else if (type === TransactionType.Deposit) {
    const depositGroupId = rest[0];
    await ws.db
      .mktx((x) => ({
        depositGroups: x.depositGroups,
        tombstones: x.tombstones,
      }))
      .runReadWrite(async (tx) => {
        const tipRecord = await tx.depositGroups.get(depositGroupId);
        if (tipRecord) {
          await tx.depositGroups.delete(depositGroupId);
          await tx.tombstones.put({
            id: TombstoneTag.DeleteDepositGroup + ":" + depositGroupId,
          });
        }
      });
  } else if (type === TransactionType.Refund) {
    const proposalId = rest[0];
    const executionTimeStr = rest[1];

    await ws.db
      .mktx((x) => ({
        proposals: x.proposals,
        purchases: x.purchases,
        tombstones: x.tombstones,
      }))
      .runReadWrite(async (tx) => {
        const purchase = await tx.purchases.get(proposalId);
        if (purchase) {
          // This should just influence the history view,
          // but won't delete any actual refund information.
          await tx.tombstones.put({
            id: makeEventId(
              TombstoneTag.DeleteRefund,
              proposalId,
              executionTimeStr,
            ),
          });
        }
      });
  } else {
    throw Error(`can't delete a '${type}' transaction`);
  }
}