import { prisma } from "@/lib/prisma";
import type {
  BankingData,
  Account,
  Transaction,
  Folder,
  Category,
} from "@/lib/types";
import { Prisma } from "@prisma/client";

export interface TransactionsPaginatedParams {
  limit?: number;
  offset?: number;
  startDate?: string;
  endDate?: string;
  accountIds?: string[];
  categoryIds?: string[];
  includeUncategorized?: boolean;
  search?: string;
  isReconciled?: boolean | "all";
  sortField?: "date" | "amount" | "description";
  sortOrder?: "asc" | "desc";
}

export interface TransactionsPaginatedResult {
  transactions: Transaction[];
  total: number;
  hasMore: boolean;
}

export const bankingService = {
  async getAllData(): Promise<BankingData> {
    const [accounts, transactions, folders, categories] = await Promise.all([
      prisma.account.findMany({
        include: {
          folder: true,
        },
      }),
      prisma.transaction.findMany({
        // Removed includes - not needed for transformation, only use direct fields
        select: {
          id: true,
          accountId: true,
          date: true,
          amount: true,
          description: true,
          type: true,
          categoryId: true,
          isReconciled: true,
          fitId: true,
          memo: true,
          checkNum: true,
        },
      }),
      prisma.folder.findMany(),
      prisma.category.findMany(),
    ]);

    // Transform Prisma models to match our types
    return {
      accounts: accounts.map(
        (a): Account => ({
          id: a.id,
          name: a.name,
          bankId: a.bankId,
          accountNumber: a.accountNumber,
          type: a.type as Account["type"],
          folderId: a.folderId,
          balance: a.balance,
          initialBalance: a.initialBalance,
          currency: a.currency,
          lastImport: a.lastImport,
          externalUrl: a.externalUrl,
        }),
      ),
      transactions: transactions.map(
        (t): Transaction => ({
          id: t.id,
          accountId: t.accountId,
          date: t.date,
          amount: t.amount,
          description: t.description,
          type: t.type as Transaction["type"],
          categoryId: t.categoryId,
          isReconciled: t.isReconciled,
          fitId: t.fitId,
          memo: t.memo ?? undefined,
          checkNum: t.checkNum ?? undefined,
        }),
      ),
      folders: folders.map(
        (f): Folder => ({
          id: f.id,
          name: f.name,
          parentId: f.parentId,
          color: f.color,
          icon: f.icon,
        }),
      ),
      categories: categories.map(
        (c): Category => ({
          id: c.id,
          name: c.name,
          color: c.color,
          icon: c.icon,
          keywords: JSON.parse(c.keywords) as string[],
          parentId: c.parentId,
        }),
      ),
    };
  },

  async getTransactionsPaginated(
    params: TransactionsPaginatedParams = {},
  ): Promise<TransactionsPaginatedResult> {
    const {
      limit = 50,
      offset = 0,
      startDate,
      endDate,
      accountIds,
      categoryIds,
      includeUncategorized = false,
      search,
      isReconciled = "all",
      sortField = "date",
      sortOrder = "desc",
    } = params;

    // Build where clause
    const where: Prisma.TransactionWhereInput = {};

    // Date filter
    if (startDate || endDate) {
      where.date = {};
      if (startDate) {
        where.date.gte = startDate;
      }
      if (endDate) {
        // Add time to end of day
        const endOfDay = new Date(endDate);
        endOfDay.setHours(23, 59, 59, 999);
        where.date.lte = endOfDay.toISOString().split("T")[0];
      }
    }

    // Account filter
    if (accountIds && accountIds.length > 0) {
      where.accountId = { in: accountIds };
    }

    // Category filter
    const categoryFilter: Prisma.TransactionWhereInput[] = [];
    if (categoryIds && categoryIds.length > 0) {
      if (includeUncategorized) {
        categoryFilter.push({
          OR: [{ categoryId: { in: categoryIds } }, { categoryId: null }],
        });
      } else {
        categoryFilter.push({ categoryId: { in: categoryIds } });
      }
    } else if (includeUncategorized) {
      categoryFilter.push({ categoryId: null });
    }

    // Search filter (description or memo)
    // SQLite is case-insensitive by default for ASCII strings
    if (search && search.trim()) {
      const searchLower = search.toLowerCase();
      categoryFilter.push({
        OR: [
          { description: { contains: searchLower } },
          { memo: { contains: searchLower } },
        ],
      });
    }

    // Combine all filters with AND if we have multiple conditions
    if (categoryFilter.length > 0) {
      if (categoryFilter.length === 1) {
        Object.assign(where, categoryFilter[0]);
      } else {
        where.AND = categoryFilter;
      }
    }

    // Reconciled filter
    if (isReconciled !== "all") {
      where.isReconciled = isReconciled === true;
    }

    // Build orderBy
    const orderBy: Prisma.TransactionOrderByWithRelationInput[] = [];
    switch (sortField) {
      case "date":
        orderBy.push({ date: sortOrder });
        break;
      case "amount":
        orderBy.push({ amount: sortOrder });
        break;
      case "description":
        orderBy.push({ description: sortOrder });
        break;
    }
    // Add secondary sort by date for consistency
    if (sortField !== "date") {
      orderBy.push({ date: "desc" });
    }

    // Get total count
    const total = await prisma.transaction.count({ where });

    // Get paginated transactions
    const transactions = await prisma.transaction.findMany({
      where,
      orderBy,
      take: limit,
      skip: offset,
      select: {
        id: true,
        accountId: true,
        date: true,
        amount: true,
        description: true,
        type: true,
        categoryId: true,
        isReconciled: true,
        fitId: true,
        memo: true,
        checkNum: true,
      },
    });

    // Transform to Transaction type
    const transformedTransactions: Transaction[] = transactions.map(
      (t): Transaction => ({
        id: t.id,
        accountId: t.accountId,
        date: t.date,
        amount: t.amount,
        description: t.description,
        type: t.type as Transaction["type"],
        categoryId: t.categoryId,
        isReconciled: t.isReconciled,
        fitId: t.fitId,
        memo: t.memo ?? undefined,
        checkNum: t.checkNum ?? undefined,
      }),
    );

    return {
      transactions: transformedTransactions,
      total,
      hasMore: offset + limit < total,
    };
  },

  async getMetadata(): Promise<{
    accounts: Account[];
    folders: Folder[];
    categories: Category[];
  }> {
    const [accounts, folders, categories] = await Promise.all([
      prisma.account.findMany({
        include: {
          folder: true,
        },
      }),
      prisma.folder.findMany(),
      prisma.category.findMany(),
    ]);

    return {
      accounts: accounts.map(
        (a): Account => ({
          id: a.id,
          name: a.name,
          bankId: a.bankId,
          accountNumber: a.accountNumber,
          type: a.type as Account["type"],
          folderId: a.folderId,
          balance: a.balance,
          initialBalance: a.initialBalance,
          currency: a.currency,
          lastImport: a.lastImport,
          externalUrl: a.externalUrl,
        }),
      ),
      folders: folders.map(
        (f): Folder => ({
          id: f.id,
          name: f.name,
          parentId: f.parentId,
          color: f.color,
          icon: f.icon,
        }),
      ),
      categories: categories.map(
        (c): Category => ({
          id: c.id,
          name: c.name,
          color: c.color,
          icon: c.icon,
          keywords: JSON.parse(c.keywords) as string[],
          parentId: c.parentId,
        }),
      ),
    };
  },

  async getCategoryStats(): Promise<
    Record<string, { count: number; total: number }>
  > {
    // Get stats for all categories in one query using aggregation
    // We need to sum absolute values, so we'll do it in two steps
    const stats = await prisma.transaction.groupBy({
      by: ["categoryId"],
      where: {
        categoryId: { not: null },
      },
      _count: {
        id: true,
      },
    });

    const statsMap: Record<string, { count: number; total: number }> = {};

    // Get uncategorized count
    const uncategorizedCount = await prisma.transaction.count({
      where: { categoryId: null },
    });
    statsMap["uncategorized"] = {
      count: uncategorizedCount,
      total: 0,
    };

    // For each category, calculate total with absolute values
    for (const stat of stats) {
      if (stat.categoryId) {
        const categoryTransactions = await prisma.transaction.findMany({
          where: { categoryId: stat.categoryId },
          select: { amount: true },
        });

        const total = categoryTransactions.reduce(
          (sum, t) => sum + Math.abs(t.amount),
          0,
        );

        statsMap[stat.categoryId] = {
          count: stat._count.id,
          total,
        };
      }
    }

    return statsMap;
  },

  async getAccountsWithStats(): Promise<
    Array<Account & { transactionCount: number }>
  > {
    const accounts = await prisma.account.findMany({
      include: {
        folder: true,
      },
    });

    // Get transaction counts for all accounts in one query
    const transactionCounts = await prisma.transaction.groupBy({
      by: ["accountId"],
      _count: {
        id: true,
      },
    });

    const countMap = new Map<string, number>();
    transactionCounts.forEach((tc) => {
      countMap.set(tc.accountId, tc._count.id);
    });

    return accounts.map((a): Account & { transactionCount: number } => ({
      id: a.id,
      name: a.name,
      bankId: a.bankId,
      accountNumber: a.accountNumber,
      type: a.type as Account["type"],
      folderId: a.folderId,
      balance: a.balance,
      initialBalance: a.initialBalance,
      currency: a.currency,
      lastImport: a.lastImport,
      externalUrl: a.externalUrl,
      transactionCount: countMap.get(a.id) || 0,
    }));
  },
};