import * as plugins from './plugins.js';
import * as path from 'path';
import type { IAccountData, ITransactionData, IJournalEntry, TSKRType } from './skr.types.js';

export interface IExportOptions {
  exportPath: string;
  fiscalYear: number;
  dateFrom: Date;
  dateTo: Date;
  includeDocuments?: boolean;
  generatePdfReports?: boolean;
  signExport?: boolean;
  timestampExport?: boolean;
  companyInfo?: {
    name: string;
    taxId: string;
    registrationNumber?: string;
    address?: string;
  };
}

export interface IExportMetadata {
  exportVersion: string;
  exportTimestamp: string;
  generator: {
    name: string;
    version: string;
  };
  company?: {
    name: string;
    taxId: string;
    registrationNumber?: string;
    address?: string;
  };
  fiscalYear: number;
  dateRange: {
    from: string;
    to: string;
  };
  skrType: TSKRType;
  schemaVersion: string;
  crypto: {
    digestAlgorithms: string[];
    signatureType?: string;
    timestampPolicy?: string;
    merkleTree: boolean;
  };
  options: {
    packagedAs: 'bagit';
    compression: 'none' | 'deflate';
    deduplication: boolean;
  };
}

export interface IBagItManifest {
  [filePath: string]: string; // filePath -> SHA256 hash
}

export interface IDocumentIndex {
  contentHash: string;
  sizeBytes: number;
  mimeType: string;
  createdAt: string;
  originalFilename?: string;
  pdfaAvailable: boolean;
  zugferdXml?: string;
  retentionClass: string;
}

export class SkrExport {
  private logger: plugins.smartlog.ConsoleLog;
  private options: IExportOptions;
  private exportDir: string;
  private manifest: IBagItManifest = {};
  private tagManifest: IBagItManifest = {};
  
  constructor(options: IExportOptions) {
    this.options = options;
    this.logger = new plugins.smartlog.ConsoleLog();
    this.exportDir = path.join(options.exportPath, `jahresabschluss_${options.fiscalYear}`);
  }

  /**
   * Creates the BagIt directory structure for the export
   */
  public async createBagItStructure(): Promise<void> {
    this.logger.log('info', 'Creating BagIt directory structure...');
    
    // Create main directories
    await plugins.smartfile.fs.ensureDir(this.exportDir);
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'metadata'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'metadata', 'schemas'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'metadata', 'schemas', 'v1'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'metadata', 'signatures'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'accounting'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'accounting', 'ebilanz'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'documents'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'documents', 'by-hash'));
    await plugins.smartfile.fs.ensureDir(path.join(this.exportDir, 'data', 'reports'));
    
    // Create BagIt declaration file
    await this.createBagItDeclaration();
    
    // Create README
    await this.createReadme();
    
    this.logger.log('ok', 'BagIt structure created successfully');
  }

  /**
   * Creates the bagit.txt declaration file
   */
  private async createBagItDeclaration(): Promise<void> {
    const bagitContent = `BagIt-Version: 1.0
Tag-File-Character-Encoding: UTF-8`;
    
    const filePath = path.join(this.exportDir, 'bagit.txt');
    await plugins.smartfile.memory.toFs(bagitContent, filePath);
    
    // Add to tag manifest
    const hash = await this.hashFile(filePath);
    this.tagManifest['bagit.txt'] = hash;
  }

  /**
   * Creates the README.txt file with Verfahrensdokumentation
   */
  private async createReadme(): Promise<void> {
    const readmeContent = `SKR Jahresabschluss Export - Verfahrensdokumentation
=====================================================

Dieses Archiv enthält einen revisionssicheren Export des Jahresabschlusses
gemäß den Grundsätzen ordnungsmäßiger Buchführung (GoBD).

Export-Datum: ${new Date().toISOString()}
Geschäftsjahr: ${this.options.fiscalYear}
Zeitraum: ${this.options.dateFrom.toISOString()} bis ${this.options.dateTo.toISOString()}

STRUKTUR DES ARCHIVS
--------------------
- /data/accounting/: Buchhaltungsdaten (Journale, Konten, Salden)
- /data/documents/: Belegdokumente (content-adressiert)
- /data/reports/: Finanzberichte (PDF/A-3)
- /data/metadata/: Export-Metadaten und Schemas
- /data/metadata/signatures/: Digitale Signaturen und Zeitstempel

INTEGRITÄTSSICHERUNG
--------------------
- Alle Dateien sind mit SHA-256 gehasht (siehe manifest-sha256.txt)
- Optional: Digitale Signatur (CAdES) über Manifest
- Optional: RFC 3161 Zeitstempel

AUFBEWAHRUNG
------------
Dieses Archiv muss gemäß § 147 AO für 10 Jahre revisionssicher aufbewahrt werden.
Empfohlen wird die Speicherung auf WORM-Medien.

REIMPORT
--------
Das Archiv kann mit der SKR-Software vollständig reimportiert werden.
Die Datenintegrität wird beim Import automatisch verifiziert.

COMPLIANCE
----------
- GoBD-konform
- E-Bilanz-fähig (XBRL)
- ZUGFeRD/Factur-X kompatibel
- PDF/A-3 für Langzeitarchivierung

© ${new Date().getFullYear()} ${this.options.companyInfo?.name || 'Export System'}`;

    const filePath = path.join(this.exportDir, 'readme.txt');
    await plugins.smartfile.memory.toFs(readmeContent, filePath);
    
    // Add to tag manifest
    const hash = await this.hashFile(filePath);
    this.tagManifest['readme.txt'] = hash;
  }

  /**
   * Creates the export metadata JSON file
   */
  public async createExportMetadata(skrType: TSKRType): Promise<void> {
    const metadata: IExportMetadata = {
      exportVersion: '1.0.0',
      exportTimestamp: new Date().toISOString(),
      generator: {
        name: '@fin.cx/skr',
        version: '1.1.0' // Should be read from package.json
      },
      company: this.options.companyInfo,
      fiscalYear: this.options.fiscalYear,
      dateRange: {
        from: this.options.dateFrom.toISOString(),
        to: this.options.dateTo.toISOString()
      },
      skrType: skrType,
      schemaVersion: '1.0',
      crypto: {
        digestAlgorithms: ['sha256'],
        signatureType: this.options.signExport ? 'CAdES' : undefined,
        timestampPolicy: this.options.timestampExport ? 'RFC3161' : undefined,
        merkleTree: true
      },
      options: {
        packagedAs: 'bagit',
        compression: 'none',
        deduplication: true
      }
    };

    const filePath = path.join(this.exportDir, 'data', 'metadata', 'export.json');
    await plugins.smartfile.memory.toFs(JSON.stringify(metadata, null, 2), filePath);
    
    // Add to manifest
    const hash = await this.hashFile(filePath);
    this.manifest['data/metadata/export.json'] = hash;
  }

  /**
   * Creates JSON schemas for the export data structures
   */
  public async createSchemas(): Promise<void> {
    // Ledger schema
    const ledgerSchema = {
      "$schema": "http://json-schema.org/draft-07/schema#",
      "title": "Ledger Entry",
      "type": "object",
      "properties": {
        "schema_version": { "type": "string" },
        "entry_id": { "type": "string", "format": "uuid" },
        "booking_date": { "type": "string", "format": "date" },
        "posting_date": { "type": "string", "format": "date" },
        "currency": { "type": "string" },
        "journal": { "type": "string" },
        "description": { "type": "string" },
        "lines": {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "posting_id": { "type": "string" },
              "account_code": { "type": "string" },
              "debit": { "type": "string" },
              "credit": { "type": "string" },
              "tax_code": { "type": "string" },
              "document_refs": {
                "type": "array",
                "items": {
                  "type": "object",
                  "properties": {
                    "content_hash": { "type": "string" },
                    "doc_role": { "type": "string" },
                    "mime": { "type": "string" }
                  }
                }
              }
            },
            "required": ["posting_id", "account_code", "debit", "credit"]
          }
        },
        "created_at": { "type": "string", "format": "date-time" },
        "user": { "type": "string" }
      },
      "required": ["schema_version", "entry_id", "booking_date", "lines"]
    };

    // Accounts schema
    const accountsSchema = {
      "$schema": "http://json-schema.org/draft-07/schema#",
      "title": "Accounts CSV",
      "type": "object",
      "properties": {
        "account_code": { "type": "string" },
        "name": { "type": "string" },
        "type": { "type": "string" },
        "parent": { "type": "string" },
        "skr_set": { "type": "string" },
        "tax_code_default": { "type": "string" },
        "active_from": { "type": "string", "format": "date" },
        "active_to": { "type": "string", "format": "date" }
      },
      "required": ["account_code", "name", "type", "skr_set"]
    };

    // Save schemas
    const schemasDir = path.join(this.exportDir, 'data', 'metadata', 'schemas', 'v1');
    
    await plugins.smartfile.memory.toFs(
      JSON.stringify(ledgerSchema, null, 2),
      path.join(schemasDir, 'ledger.schema.json')
    );
    this.manifest['data/metadata/schemas/v1/ledger.schema.json'] = await this.hashFile(
      path.join(schemasDir, 'ledger.schema.json')
    );

    await plugins.smartfile.memory.toFs(
      JSON.stringify(accountsSchema, null, 2),
      path.join(schemasDir, 'accounts.schema.json')
    );
    this.manifest['data/metadata/schemas/v1/accounts.schema.json'] = await this.hashFile(
      path.join(schemasDir, 'accounts.schema.json')
    );
  }

  /**
   * Writes the BagIt manifest files
   */
  public async writeManifests(): Promise<void> {
    // Write data manifest
    let manifestContent = '';
    for (const [filePath, hash] of Object.entries(this.manifest)) {
      manifestContent += `${hash}  ${filePath}\n`;
    }
    
    const manifestPath = path.join(this.exportDir, 'manifest-sha256.txt');
    await plugins.smartfile.memory.toFs(manifestContent, manifestPath);
    
    // Add manifest to tag manifest
    this.tagManifest['manifest-sha256.txt'] = await this.hashFile(manifestPath);
    
    // Write tag manifest
    let tagManifestContent = '';
    for (const [filePath, hash] of Object.entries(this.tagManifest)) {
      tagManifestContent += `${hash}  ${filePath}\n`;
    }
    
    await plugins.smartfile.memory.toFs(
      tagManifestContent,
      path.join(this.exportDir, 'tagmanifest-sha256.txt')
    );
  }

  /**
   * Calculates SHA-256 hash of a file
   */
  private async hashFile(filePath: string): Promise<string> {
    const fileContent = await plugins.smartfile.fs.toBuffer(filePath);
    return await plugins.smarthash.sha256FromBuffer(fileContent);
  }

  /**
   * Stores a document in content-addressed storage
   */
  public async storeDocument(content: Buffer, originalFilename?: string): Promise<string> {
    const hash = await plugins.smarthash.sha256FromBuffer(content);
    
    // Create path based on hash (first 2 chars as directory)
    const hashPrefix = hash.substring(0, 2);
    const hashDir = path.join(this.exportDir, 'data', 'documents', 'by-hash', hashPrefix);
    await plugins.smartfile.fs.ensureDir(hashDir);
    
    const docPath = path.join(hashDir, hash);
    
    // Only store if not already exists (deduplication)
    if (!(await plugins.smartfile.fs.fileExists(docPath))) {
      await plugins.smartfile.memory.toFs(content, docPath);
      this.manifest[`data/documents/by-hash/${hashPrefix}/${hash}`] = hash;
    }
    
    return hash;
  }

  /**
   * Creates a Merkle tree from all file hashes
   */
  public async createMerkleTree(): Promise<string> {
    const leaves = Object.values(this.manifest).map(hash => 
      Buffer.from(hash, 'hex')
    );
    
    // Create a sync hash function wrapper for MerkleTree
    const hashFn = (data: Buffer) => {
      // Convert async to sync by using crypto directly
      const crypto = require('crypto');
      return crypto.createHash('sha256').update(data).digest();
    };
    
    const tree = new plugins.MerkleTree(leaves, hashFn, {
      sortPairs: true
    });
    
    const root = tree.getRoot().toString('hex');
    
    // Save Merkle tree data
    const merkleData = {
      root: root,
      leaves: Object.entries(this.manifest).map(([path, hash]) => ({
        path,
        hash
      })),
      timestamp: new Date().toISOString()
    };
    
    const merklePath = path.join(this.exportDir, 'data', 'metadata', 'merkle-tree.json');
    await plugins.smartfile.memory.toFs(JSON.stringify(merkleData, null, 2), merklePath);
    this.manifest['data/metadata/merkle-tree.json'] = await this.hashFile(merklePath);
    
    return root;
  }

  /**
   * Validates the BagIt structure
   */
  public async validateBagIt(): Promise<boolean> {
    this.logger.log('info', 'Validating BagIt structure...');
    
    // Check required files exist
    const requiredFiles = [
      'bagit.txt',
      'manifest-sha256.txt',
      'tagmanifest-sha256.txt',
      'readme.txt'
    ];
    
    for (const file of requiredFiles) {
      const filePath = path.join(this.exportDir, file);
      if (!(await plugins.smartfile.fs.fileExists(filePath))) {
        this.logger.log('error', `Required file missing: ${file}`);
        return false;
      }
    }
    
    // Verify all manifest entries
    for (const [relPath, expectedHash] of Object.entries(this.manifest)) {
      const fullPath = path.join(this.exportDir, relPath);
      if (!(await plugins.smartfile.fs.fileExists(fullPath))) {
        this.logger.log('error', `Manifest file missing: ${relPath}`);
        return false;
      }
      
      const actualHash = await this.hashFile(fullPath);
      if (actualHash !== expectedHash) {
        this.logger.log('error', `Hash mismatch for ${relPath}`);
        return false;
      }
    }
    
    this.logger.log('ok', 'BagIt validation successful');
    return true;
  }
}