import { ZipArchive } from "archiver";
import * as storage from "../storage/documents.storage";
import { DocumentGenerationService } from "./generation.service";
import { uploadToS3 } from "../utils/s3";
import { db } from "../db";
import { fileUploads } from "@shared/schema";
import type { DocumentPackage, DocumentPackageItem } from "@shared/schema";

export interface GeneratePackageRequest {
  packageId: number;
  taskId: number;
  organizationId: number;
  userId: number;
}

export interface GeneratePackageResult {
  packageId: number;
  zipUrl: string;
  generatedFiles: number;
  skippedItems: number;
}

export class PackageService {
  constructor(private generationService: DocumentGenerationService) {}

  async list(organizationId: number): Promise<Array<DocumentPackage & { items: DocumentPackageItem[] }>> {
    const packages = await storage.listDocumentPackages(organizationId);
    const result: Array<DocumentPackage & { items: DocumentPackageItem[] }> = [];
    for (const pkg of packages) {
      const items = await storage.listDocumentPackageItems(pkg.id);
      result.push({ ...pkg, items });
    }
    return result;
  }

  async getById(packageId: number, organizationId: number): Promise<(DocumentPackage & { items: DocumentPackageItem[] }) | undefined> {
    const pkg = await storage.getDocumentPackage(packageId, organizationId);
    if (!pkg) return undefined;
    const items = await storage.listDocumentPackageItems(packageId);
    return { ...pkg, items };
  }

  async create(
    data: { name: string; description?: string; category?: string; items: Array<{ templateId: number; sortOrder?: number; customName?: string; condition?: any }> },
    organizationId: number,
  ): Promise<DocumentPackage & { items: DocumentPackageItem[] }> {
    const pkg = await storage.createDocumentPackage({
      organizationId,
      name: data.name,
      description: data.description,
      category: data.category,
    });

    const items: DocumentPackageItem[] = [];
    for (let i = 0; i < data.items.length; i++) {
      const item = data.items[i];
      items.push(
        await storage.createDocumentPackageItem({
          packageId: pkg.id,
          templateId: item.templateId,
          sortOrder: item.sortOrder ?? i,
          customName: item.customName,
          condition: item.condition,
        }),
      );
    }

    return { ...pkg, items };
  }

  async update(
    packageId: number,
    organizationId: number,
    data: Partial<DocumentPackage> & { items?: Array<{ id?: number; templateId: number; sortOrder?: number; customName?: string; condition?: any }> },
  ): Promise<(DocumentPackage & { items: DocumentPackageItem[] }) | undefined> {
    const pkg = await storage.updateDocumentPackage(packageId, organizationId, data);
    if (!pkg) return undefined;

    if (data.items) {
      const existing = await storage.listDocumentPackageItems(packageId);
      const incomingIds = data.items.filter((i) => i.id && i.id > 0).map((i) => i.id!);
      const toDelete = existing.filter((e) => !incomingIds.includes(e.id));
      for (const item of toDelete) {
        await storage.deleteDocumentPackageItem(item.id, packageId);
      }

      for (let i = 0; i < data.items.length; i++) {
        const item = data.items[i];
        const itemData = {
          packageId,
          templateId: item.templateId,
          sortOrder: item.sortOrder ?? i,
          customName: item.customName,
          condition: item.condition,
        };
        if (item.id && item.id > 0) {
          await storage.updateDocumentPackageItem(item.id, packageId, itemData);
        } else {
          await storage.createDocumentPackageItem(itemData);
        }
      }
    }

    return this.getById(packageId, organizationId);
  }

  async delete(packageId: number, organizationId: number): Promise<void> {
    const items = await storage.listDocumentPackageItems(packageId);
    for (const item of items) {
      await storage.deleteDocumentPackageItem(item.id, packageId);
    }
    await storage.deleteDocumentPackage(packageId, organizationId);
  }

  async generatePackage(request: GeneratePackageRequest): Promise<GeneratePackageResult> {
    const pkg = await this.getById(request.packageId, request.organizationId);
    if (!pkg) throw new Error("Пакет не найден");
    if (!pkg.items.length) throw new Error("В пакете нет шаблонов");

    const files: Array<{ name: string; buffer: Buffer; format: 'pdf' | 'docx' }> = [];
    let skippedItems = 0;

    for (const item of pkg.items) {
      // TODO: evaluate condition
      try {
        const result = await this.generationService.generate({
          templateId: item.templateId,
          taskId: request.taskId,
          organizationId: request.organizationId,
          userId: request.userId,
          outputFormat: "both",
        });

        if (result.pdfUrl) {
          const fileKey = result.pdfUrl.replace("/api/files/", "");
          const buffer = await this.downloadFile(fileKey);
          files.push({
            name: `${item.customName || `document_${item.templateId}`}.pdf`,
            buffer,
            format: "pdf",
          });
        }
        if (result.docxUrl) {
          const fileKey = result.docxUrl.replace("/api/files/", "");
          const buffer = await this.downloadFile(fileKey);
          files.push({
            name: `${item.customName || `document_${item.templateId}`}.docx`,
            buffer,
            format: "docx",
          });
        }
      } catch {
        skippedItems++;
      }
    }

    if (files.length === 0) throw new Error("Не удалось сгенерировать ни одного документа");

    const zipBuffer = await this.createZip(files);
    const zipName = `${pkg.name}-${Date.now()}.zip`;
    const { key } = await uploadToS3(zipBuffer, zipName, "application/zip");

    try {
      await db.insert(fileUploads).values({
        organizationId: request.organizationId,
        uploadedBy: request.userId,
        fileKey: key,
        originalName: zipName,
        sizeBytes: zipBuffer.length,
        taskId: request.taskId,
        fieldId: null,
      }).onConflictDoNothing();
    } catch (err) {
      console.warn('[Documents] Failed to track package zip:', err);
    }

    return {
      packageId: pkg.id,
      zipUrl: `/api/files/${key}`,
      generatedFiles: files.length,
      skippedItems,
    };
  }

  private async downloadFile(fileKey: string): Promise<Buffer> {
    const { isS3Enabled, streamFromS3 } = await import("../utils/s3.js");
    const fs = await import("fs/promises");
    const path = await import("path");

    if (isS3Enabled) {
      const result = await streamFromS3(fileKey);
      if (!result?.body) throw new Error("Не удалось загрузить файл");
      const chunks: Buffer[] = [];
      for await (const chunk of result.body as any) {
        chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
      }
      return Buffer.concat(chunks);
    }

    const filePath = path.join(process.env.UPLOADS_DIR || "/app/data/uploads", path.basename(fileKey));
    return fs.readFile(filePath);
  }

  private async createZip(files: Array<{ name: string; buffer: Buffer; format: 'pdf' | 'docx' }>): Promise<Buffer> {
    return new Promise((resolve, reject) => {
      const archive = new ZipArchive({ zlib: { level: 9 } });
      const chunks: Buffer[] = [];

      archive.on("data", (chunk: Buffer) => chunks.push(chunk));
      archive.on("end", () => resolve(Buffer.concat(chunks)));
      archive.on("error", (err: Error) => reject(err));

      for (const file of files) {
        archive.append(file.buffer, { name: file.name });
      }

      archive.finalize();
    });
  }
}