import { Injectable } from '@nestjs/common';
import { randomUUID } from 'node:crypto';

import { BankCard, Prisma } from '../../../../../generated/prisma/client';
import { isPrismaErrorCode, PrismaErrorCode } from '../../../../prisma/prisma-error-code';
import { PrismaService } from '../../../../prisma/prisma.service';
import {
  BankErrorCode,
  conflict,
  missing,
} from '../application/bank-card-input';
import { BankOperationKind } from '../domain/bank-operation-kind';

const INITIAL_RETRY_COUNT = 0;
const LAST_SEED_OFFSET = 1;
const EXPECTED_UPDATED_CARDS = 1;
const EXPECTED_UPDATED_CATEGORIES = 1;
const VERSION_INCREMENT = 1;

type Tx = Prisma.TransactionClient;
const TRANSACTION_MAX_WAIT_MS = 10_000;
const TRANSACTION_TIMEOUT_MS = 15_000;
const MAX_WRITE_RETRY_COUNT = 2;
const seeds = [
  'Продукты',
  'Кафе',
  'Такси',
  'Транспорт',
  'Жильё',
  'Здоровье',
  'Покупки',
  'Развлечения',
  'Другое',
];
@Injectable()
export class BankCardsRepository {
  constructor(private readonly prisma: PrismaService) {}

  read<T>(run: (tx: Tx) => Promise<T>): Promise<T> {
    return this.prisma.$transaction(run);
  }

  cards(tx: Tx, userId: string, includeArchived = false) {
    return tx.bankCard.findMany({
      where: { userId, ...(includeArchived ? {} : { archivedAt: null }) },
      orderBy: [{ createdAt: 'asc' }, { id: 'asc' }],
    });
  }

  cardOperations(tx: Tx, card: BankCard) {
    return tx.bankCardOperation.findMany({
      where: {
        userId: card.userId,
        deletedAt: null,
        OR: [{ cardId: card.id }, { targetCardId: card.id }],
      },
    });
  }

  cardById(tx: Tx, id: string) {
    return tx.bankCard.findUnique({ where: { id } });
  }

  createCard(tx: Tx, data: Prisma.BankCardUncheckedCreateInput) {
    return tx.bankCard.create({ data });
  }

  async updateCard(
    tx: Tx,
    userId: string,
    id: string,
    version: number,
    data: Prisma.BankCardUpdateManyMutationInput,
  ) {
    const changed = await tx.bankCard.updateMany({
      where: { id, userId, version },
      data,
    });
    if (changed.count !== EXPECTED_UPDATED_CARDS) conflict();
    return this.card(tx, userId, id);
  }

  hasOperationsBefore(tx: Tx, userId: string, id: string, openingDate: string) {
    return tx.bankCardOperation.findFirst({
      where: {
        userId,
        deletedAt: null,
        date: { lt: openingDate },
        OR: [{ cardId: id }, { targetCardId: id }],
      },
    });
  }

  async categories(userId: string) {
    return (
      await this.prisma.expenseCategory.findMany({
        where: { userId },
        orderBy: [{ name: 'asc' }, { id: 'asc' }],
      })
    ).map(({ id, name, seedKey, version }) => ({
      id,
      name,
      isDefault: seedKey === 'other',
      version,
    }));
  }

  createCategory(userId: string, label: string) {
    return this.write(async (tx) => {
      await this.seed(tx, userId);
      const row = await tx.expenseCategory.create({
        data: {
          id: randomUUID(),
          userId,
          name: label,
          nameKey: label.toLocaleLowerCase('ru-RU'),
        },
      });
      return {
        id: row.id,
        name: row.name,
        isDefault: false,
        version: row.version,
      };
    });
  }

  updateCategory(userId: string, id: string, label: string, version: number) {
    return this.write(async (tx) => {
      const row = await tx.expenseCategory.findFirst({ where: { id, userId } });
      if (!row) missing();
      if (
        (
          await tx.expenseCategory.updateMany({
            where: { id, userId, version },
            data: {
              name: label,
              nameKey: label.toLocaleLowerCase('ru-RU'),
              version: { increment: 1 },
            },
          })
        ).count !== EXPECTED_UPDATED_CATEGORIES
      ) {
        conflict();
      }
      return {
        id,
        name: label,
        isDefault: row.seedKey === 'other',
        version: version + VERSION_INCREMENT,
      };
    });
  }

  async write<T>(run: (tx: Tx) => Promise<T>): Promise<T> {
    for (let attempt = INITIAL_RETRY_COUNT; ; attempt++) {
      try {
        return await this.prisma.$transaction(run, {
          maxWait: TRANSACTION_MAX_WAIT_MS,
          timeout: TRANSACTION_TIMEOUT_MS,
        });
      } catch (error) {
        const code =
          error instanceof Prisma.PrismaClientKnownRequestError
            ? error.code
            : '';
        const busy =
          isPrismaErrorCode(code, PrismaErrorCode.WriteConflict) ||
          isPrismaErrorCode(code, PrismaErrorCode.TransactionFailure) ||
          (error instanceof Error &&
            /SQLITE_BUSY|database is locked/.test(error.message));
        if (busy && attempt < MAX_WRITE_RETRY_COUNT) {
          continue;
        }
        if (busy) conflict(BankErrorCode.WriteConflict);
        if (isPrismaErrorCode(code, PrismaErrorCode.UniqueConstraint)) conflict(BankErrorCode.DuplicateCategory);
        throw error;
      }
    }
  }

  async card(tx: Tx, userId: string, id: string, active = false) {
    const card = await tx.bankCard.findFirst({ where: { id, userId } });
    if (!card) return missing();
    if (active && card.archivedAt) conflict(BankErrorCode.CardArchived);
    return card;
  }

  async operation(tx: Tx, userId: string, id: string) {
    const row = await tx.bankCardOperation.findFirst({ where: { id, userId } });
    if (!row) return missing();
    return row;
  }

  async seed(tx: Tx, userId: string) {
    for (const [index, label] of seeds.entries()) {
      const seedKey = index === seeds.length - LAST_SEED_OFFSET ? 'other' : String(index);
      if (
        !(await tx.expenseCategory.findUnique({
          where: { userId_seedKey: { userId, seedKey } },
        }))
      ) {
        await tx.expenseCategory.create({
          data: {
            id: randomUUID(),
            userId,
            seedKey,
            name: label,
            nameKey: label.toLocaleLowerCase('ru-RU'),
          },
        });
      }
    }
  }

  summaryData(
    userId: string,
    period: { from: string; to: string },
    cardId?: string,
  ) {
    return this.prisma.$transaction(async (tx) => {
      if (cardId) await this.card(tx, userId, cardId);
      const rows = await tx.bankCardOperation.findMany({
        where: {
          userId,
          deletedAt: null,
          date: { gte: period.from, lte: period.to },
          kind: { in: [BankOperationKind.Expense, BankOperationKind.Refund] },
          ...(cardId ? { cardId } : {}),
        },
        include: { originalExpense: { select: { categoryId: true } } },
      });
      const categories = await tx.expenseCategory.findMany({
        where: { userId },
      });
      return {
        operations: rows.map((row) => ({
          ...row,
          categoryId: row.originalExpense?.categoryId ?? row.categoryId,
        })),
        categories,
      };
    });
  }
}