import { writeFileSync, mkdirSync } from "fs";

mkdirSync("src/stripe", { recursive: true });

// ─── stripe.service.ts ───────────────────────────────────────────────────────
writeFileSync("src/stripe/stripe.service.ts", `import { BadRequestException, Injectable, Logger } from "@nestjs/common";
import Stripe from "stripe";
import { PrismaService } from "../prisma/prisma.service";

export const PLAN_LIMITS: Record<string, { accounts: number; exports: number }> = {
  free: { accounts: 2, exports: 5 },
  pro: { accounts: 10, exports: 100 },
  elite: { accounts: -1, exports: -1 }, // -1 = unlimited
};

@Injectable()
export class StripeService {
  private readonly stripe: Stripe;
  private readonly logger = new Logger(StripeService.name);

  constructor(private readonly prisma: PrismaService) {
    const key = process.env.STRIPE_SECRET_KEY;
    if (!key) throw new Error("STRIPE_SECRET_KEY is required.");
    this.stripe = new Stripe(key, { apiVersion: "2025-01-27.acacia" });
  }

  async getOrCreateCustomer(userId: string, email: string): Promise<string> {
    const sub = await this.prisma.subscription.findUnique({ where: { userId } });
    if (sub?.stripeCustomerId) return sub.stripeCustomerId;

    const customer = await this.stripe.customers.create({ email, metadata: { userId } });
    await this.prisma.subscription.upsert({
      where: { userId },
      update: { stripeCustomerId: customer.id },
      create: { userId, plan: "free", stripeCustomerId: customer.id },
    });
    return customer.id;
  }

  async createCheckoutSession(userId: string, email: string, priceId: string) {
    const customerId = await this.getOrCreateCustomer(userId, email);
    const session = await this.stripe.checkout.sessions.create({
      customer: customerId,
      payment_method_types: ["card"],
      mode: "subscription",
      line_items: [{ price: priceId, quantity: 1 }],
      success_url: \`\${process.env.APP_URL}/settings/billing?success=true\`,
      cancel_url: \`\${process.env.APP_URL}/settings/billing?cancelled=true\`,
      metadata: { userId },
    });
    return { url: session.url };
  }

  async createPortalSession(userId: string) {
    const sub = await this.prisma.subscription.findUnique({ where: { userId } });
    if (!sub?.stripeCustomerId) {
      throw new BadRequestException("No Stripe customer found. Please upgrade first.");
    }
    const session = await this.stripe.billingPortal.sessions.create({
      customer: sub.stripeCustomerId,
      return_url: \`\${process.env.APP_URL}/settings/billing\`,
    });
    return { url: session.url };
  }

  async getSubscription(userId: string) {
    const sub = await this.prisma.subscription.findUnique({ where: { userId } });
    return sub ?? { userId, plan: "free" };
  }

  async handleWebhook(rawBody: Buffer, signature: string) {
    const secret = process.env.STRIPE_WEBHOOK_SECRET;
    if (!secret) throw new Error("STRIPE_WEBHOOK_SECRET is required.");

    let event: Stripe.Event;
    try {
      event = this.stripe.webhooks.constructEvent(rawBody, signature, secret);
    } catch (err) {
      this.logger.warn(\`Webhook signature verification failed: \${err}\`);
      throw new BadRequestException("Invalid webhook signature.");
    }

    switch (event.type) {
      case "customer.subscription.created":
      case "customer.subscription.updated": {
        const subscription = event.data.object as Stripe.Subscription;
        await this.syncSubscription(subscription);
        break;
      }
      case "customer.subscription.deleted": {
        const subscription = event.data.object as Stripe.Subscription;
        const customerId = subscription.customer as string;
        const sub = await this.prisma.subscription.findFirst({
          where: { stripeCustomerId: customerId },
        });
        if (sub) {
          await this.prisma.subscription.update({
            where: { userId: sub.userId },
            data: { plan: "free", stripeSubId: null, currentPeriodEnd: null, cancelAtPeriodEnd: false },
          });
        }
        break;
      }
      default:
        this.logger.debug(\`Unhandled Stripe event: \${event.type}\`);
    }

    return { received: true };
  }

  private async syncSubscription(subscription: Stripe.Subscription) {
    const customerId = subscription.customer as string;
    const sub = await this.prisma.subscription.findFirst({
      where: { stripeCustomerId: customerId },
    });
    if (!sub) return;

    const priceId = subscription.items.data[0]?.price.id;
    let plan = "free";
    if (priceId === process.env.STRIPE_PRICE_PRO) plan = "pro";
    else if (priceId === process.env.STRIPE_PRICE_ELITE) plan = "elite";

    await this.prisma.subscription.update({
      where: { userId: sub.userId },
      data: {
        plan,
        stripeSubId: subscription.id,
        currentPeriodEnd: new Date(subscription.current_period_end * 1000),
        cancelAtPeriodEnd: subscription.cancel_at_period_end,
      },
    });
  }
}
`);

// ─── stripe.controller.ts ────────────────────────────────────────────────────
writeFileSync("src/stripe/stripe.controller.ts", `import {
  Body,
  Controller,
  Get,
  Headers,
  Post,
  RawBodyRequest,
  Req,
} from "@nestjs/common";
import { Request } from "express";
import { ok } from "../common/response";
import { StripeService } from "./stripe.service";
import { CurrentUser } from "../common/decorators/current-user.decorator";
import { Public } from "../common/decorators/public.decorator";
import { PrismaService } from "../prisma/prisma.service";

@Controller("billing")
export class StripeController {
  constructor(
    private readonly stripeService: StripeService,
    private readonly prisma: PrismaService,
  ) {}

  @Get("subscription")
  async getSubscription(@CurrentUser() userId: string) {
    const data = await this.stripeService.getSubscription(userId);
    return ok(data);
  }

  @Post("checkout")
  async checkout(@CurrentUser() userId: string, @Body("priceId") priceId: string) {
    const user = await this.prisma.user.findUnique({
      where: { id: userId },
      select: { email: true },
    });
    if (!user) return ok({ error: "User not found" });
    const data = await this.stripeService.createCheckoutSession(userId, user.email, priceId);
    return ok(data);
  }

  @Post("portal")
  async portal(@CurrentUser() userId: string) {
    const data = await this.stripeService.createPortalSession(userId);
    return ok(data);
  }

  @Public()
  @Post("webhook")
  async webhook(
    @Req() req: RawBodyRequest<Request>,
    @Headers("stripe-signature") signature: string,
  ) {
    const data = await this.stripeService.handleWebhook(req.rawBody!, signature);
    return data;
  }
}
`);

// ─── subscription.guard.ts ───────────────────────────────────────────────────
writeFileSync("src/stripe/subscription.guard.ts", `import {
  CanActivate,
  ExecutionContext,
  ForbiddenException,
  Injectable,
  SetMetadata,
} from "@nestjs/common";
import { Reflector } from "@nestjs/core";
import { Request } from "express";
import { PrismaService } from "../prisma/prisma.service";

export const REQUIRED_PLAN_KEY = "requiredPlan";
export const RequiredPlan = (plan: "pro" | "elite") =>
  SetMetadata(REQUIRED_PLAN_KEY, plan);

const PLAN_RANK: Record<string, number> = { free: 0, pro: 1, elite: 2 };

@Injectable()
export class SubscriptionGuard implements CanActivate {
  constructor(
    private readonly reflector: Reflector,
    private readonly prisma: PrismaService,
  ) {}

  async canActivate(context: ExecutionContext): Promise<boolean> {
    const required = this.reflector.getAllAndOverride<string>(REQUIRED_PLAN_KEY, [
      context.getHandler(),
      context.getClass(),
    ]);
    if (!required) return true;

    const request = context.switchToHttp().getRequest<Request & { user?: { sub: string } }>();
    const userId = request.user?.sub;
    if (!userId) throw new ForbiddenException("Authentication required.");

    const sub = await this.prisma.subscription.findUnique({ where: { userId } });
    const currentPlan = sub?.plan ?? "free";
    const currentRank = PLAN_RANK[currentPlan] ?? 0;
    const requiredRank = PLAN_RANK[required] ?? 0;

    if (currentRank < requiredRank) {
      throw new ForbiddenException(\`This feature requires a \${required} plan.\`);
    }
    return true;
  }
}
`);

// ─── stripe.module.ts ────────────────────────────────────────────────────────
writeFileSync("src/stripe/stripe.module.ts", `import { Module } from "@nestjs/common";
import { StripeController } from "./stripe.controller";
import { StripeService } from "./stripe.service";
import { SubscriptionGuard } from "./subscription.guard";

@Module({
  controllers: [StripeController],
  providers: [StripeService, SubscriptionGuard],
  exports: [StripeService, SubscriptionGuard],
})
export class StripeModule {}
`);

// ─── exports.service.ts (with real Google Sheets) ────────────────────────────
writeFileSync("src/exports/exports.service.ts", `import { BadRequestException, Injectable, Logger } from "@nestjs/common";
import { google } from "googleapis";
import { PrismaService } from "../prisma/prisma.service";

@Injectable()
export class ExportsService {
  private readonly logger = new Logger(ExportsService.name);

  constructor(private readonly prisma: PrismaService) {}

  private toCsv(rows: Array<Record<string, string>>) {
    if (!rows.length) return "";
    const headers = Object.keys(rows[0]);
    const escape = (value: string) => \`"\${value.replace(/"/g, '""')}"\`;
    const lines = [headers.join(",")];
    for (const row of rows) {
      lines.push(headers.map((key) => escape(row[key] ?? "")).join(","));
    }
    return lines.join("\\n");
  }

  private async getTransactions(
    userId: string,
    filters: Record<string, string>,
    limit = 1000,
  ) {
    const where: Record<string, unknown> = { account: { userId } };
    if (filters.start_date || filters.end_date) {
      where.date = {
        gte: filters.start_date ? new Date(filters.start_date) : undefined,
        lte: filters.end_date ? new Date(filters.end_date) : undefined,
      };
    }
    if (filters.min_amount || filters.max_amount) {
      where.amount = {
        gte: filters.min_amount ? Number(filters.min_amount) : undefined,
        lte: filters.max_amount ? Number(filters.max_amount) : undefined,
      };
    }
    if (filters.category) {
      where.derived = {
        is: { userCategory: { contains: filters.category, mode: "insensitive" } },
      };
    }
    if (filters.source) {
      where.source = { contains: filters.source, mode: "insensitive" };
    }
    if (filters.include_hidden !== "true") {
      where.OR = [{ derived: null }, { derived: { isHidden: false } }];
    }
    return this.prisma.transactionRaw.findMany({
      where,
      include: { derived: true },
      orderBy: { date: "desc" },
      take: limit,
    });
  }

  private toRows(transactions: Awaited<ReturnType<typeof this.getTransactions>>) {
    return transactions.map((tx) => ({
      id: tx.id,
      date: tx.date.toISOString().slice(0, 10),
      description: tx.description,
      amount: Number(tx.amount).toFixed(2),
      category: tx.derived?.userCategory ?? "",
      notes: tx.derived?.userNotes ?? "",
      hidden: tx.derived?.isHidden ? "true" : "false",
      source: tx.source,
    }));
  }

  async exportCsv(userId: string, filters: Record<string, string> = {}) {
    const transactions = await this.getTransactions(userId, filters);
    const rows = this.toRows(transactions);
    const csv = this.toCsv(rows);

    await this.prisma.exportLog.create({
      data: { userId, filters, rowCount: rows.length },
    });

    return { status: "ready", csv, rowCount: rows.length };
  }

  async exportSheets(userId: string, filters: Record<string, string> = {}) {
    // Get the user's Google connection
    const gc = await this.prisma.googleConnection.findUnique({ where: { userId } });
    if (!gc || !gc.isConnected) {
      throw new BadRequestException(
        "Google account not connected. Please connect via /api/google/connect.",
      );
    }

    const oauth2Client = new google.auth.OAuth2(
      process.env.GOOGLE_CLIENT_ID,
      process.env.GOOGLE_CLIENT_SECRET,
    );
    oauth2Client.setCredentials({
      access_token: gc.accessToken,
      refresh_token: gc.refreshToken,
    });

    // Refresh the access token if needed
    const { credentials } = await oauth2Client.refreshAccessToken();
    await this.prisma.googleConnection.update({
      where: { userId },
      data: {
        accessToken: credentials.access_token ?? gc.accessToken,
        lastSyncedAt: new Date(),
      },
    });
    oauth2Client.setCredentials(credentials);

    const sheets = google.sheets({ version: "v4", auth: oauth2Client });
    const transactions = await this.getTransactions(userId, filters);
    const rows = this.toRows(transactions);

    const sheetTitle = \`LedgerOne Export \${new Date().toISOString().slice(0, 10)}\`;

    let spreadsheetId = gc.spreadsheetId;
    if (!spreadsheetId) {
      // Create a new spreadsheet
      const spreadsheet = await sheets.spreadsheets.create({
        requestBody: { properties: { title: "LedgerOne" } },
      });
      spreadsheetId = spreadsheet.data.spreadsheetId!;
      await this.prisma.googleConnection.update({
        where: { userId },
        data: { spreadsheetId },
      });
    }

    // Add a new sheet tab
    await sheets.spreadsheets.batchUpdate({
      spreadsheetId,
      requestBody: {
        requests: [{ addSheet: { properties: { title: sheetTitle } } }],
      },
    });

    // Build values: header + data rows
    const headers = rows.length ? Object.keys(rows[0]) : ["id", "date", "description", "amount", "category", "notes", "hidden", "source"];
    const values = [
      headers,
      ...rows.map((row) => headers.map((h) => row[h as keyof typeof row] ?? "")),
    ];

    await sheets.spreadsheets.values.update({
      spreadsheetId,
      range: \`'\${sheetTitle}'!A1\`,
      valueInputOption: "RAW",
      requestBody: { values },
    });

    await this.prisma.exportLog.create({
      data: { userId, filters: { ...filters, destination: "google_sheets" }, rowCount: rows.length },
    });

    this.logger.log(\`Exported \${rows.length} rows to Google Sheets for user \${userId}\`);

    return {
      status: "exported",
      rowCount: rows.length,
      spreadsheetId,
      sheetTitle,
      url: \`https://docs.google.com/spreadsheets/d/\${spreadsheetId}\`,
    };
  }
}
`);

console.log("stripe + sheets files written");