/**
 * EU Laissez-Passer biometric verification
 * Face image comparison (DG2), fingerprint verification (DG3), match score calculation
 */

export interface BiometricVerificationResult {
  faceMatch?: {
    score: number; // 0-1, higher is better
    threshold: number;
    matched: boolean;
  };
  fingerprintMatch?: Array<{
    position: number;
    score: number; // 0-1, higher is better
    threshold: number;
    matched: boolean;
  }>;
  irisMatch?: Array<{
    position: number;
    score: number; // 0-1, higher is better
    threshold: number;
    matched: boolean;
  }>;
  overallMatch: boolean;
  confidence: number; // 0-1, overall confidence
}

export interface BiometricData {
  faceImage?: Buffer;
  fingerprints?: Array<{ position: number; image: Buffer }>;
  irisImages?: Array<{ position: number; image: Buffer }>;
}

/**
 * Biometric verification service
 * Note: This is a placeholder implementation. In production, this would use
 * actual biometric matching libraries (e.g., face_recognition, fingerprint matchers)
 */
export class BiometricVerifier {
  private faceMatchThreshold = 0.7; // Minimum similarity score for face match
  private fingerprintMatchThreshold = 0.6; // Minimum similarity score for fingerprint match
  private irisMatchThreshold = 0.7; // Minimum similarity score for iris match

  /**
   * Verify face image (DG2)
   */
  async verifyFace(
    referenceImage: Buffer,
    comparisonImage: Buffer
  ): Promise<{ score: number; threshold: number; matched: boolean }> {
    // In production, use face recognition library
    // For now, return placeholder
    const score = this.calculateImageSimilarity(referenceImage, comparisonImage);

    return {
      score,
      threshold: this.faceMatchThreshold,
      matched: score >= this.faceMatchThreshold,
    };
  }

  /**
   * Verify fingerprint (DG3)
   */
  async verifyFingerprint(
    referenceFingerprint: Buffer,
    comparisonFingerprint: Buffer,
    position: number
  ): Promise<{ position: number; score: number; threshold: number; matched: boolean }> {
    // In production, use fingerprint matching library
    // For now, return placeholder
    const score = this.calculateImageSimilarity(referenceFingerprint, comparisonFingerprint);

    return {
      position,
      score,
      threshold: this.fingerprintMatchThreshold,
      matched: score >= this.fingerprintMatchThreshold,
    };
  }

  /**
   * Verify iris (DG4)
   */
  async verifyIris(
    referenceIris: Buffer,
    comparisonIris: Buffer,
    position: number
  ): Promise<{ position: number; score: number; threshold: number; matched: boolean }> {
    // In production, use iris recognition library
    // For now, return placeholder
    const score = this.calculateImageSimilarity(referenceIris, comparisonIris);

    return {
      position,
      score,
      threshold: this.irisMatchThreshold,
      matched: score >= this.irisMatchThreshold,
    };
  }

  /**
   * Verify all biometrics
   */
  async verifyBiometrics(
    referenceData: BiometricData,
    comparisonData: BiometricData
  ): Promise<BiometricVerificationResult> {
    const result: BiometricVerificationResult = {
      overallMatch: false,
      confidence: 0,
    };

    let totalScore = 0;
    let matchCount = 0;

    // Verify face
    if (referenceData.faceImage && comparisonData.faceImage) {
      const faceMatch = await this.verifyFace(referenceData.faceImage, comparisonData.faceImage);
      result.faceMatch = faceMatch;
      totalScore += faceMatch.score;
      matchCount++;
      if (faceMatch.matched) {
        matchCount++;
      }
    }

    // Verify fingerprints
    if (referenceData.fingerprints && comparisonData.fingerprints) {
      result.fingerprintMatch = [];
      for (const refFp of referenceData.fingerprints) {
        const compFp = comparisonData.fingerprints.find((fp) => fp.position === refFp.position);
        if (compFp) {
          const fpMatch = await this.verifyFingerprint(refFp.image, compFp.image, refFp.position);
          result.fingerprintMatch.push(fpMatch);
          totalScore += fpMatch.score;
          matchCount++;
          if (fpMatch.matched) {
            matchCount++;
          }
        }
      }
    }

    // Verify iris
    if (referenceData.irisImages && comparisonData.irisImages) {
      result.irisMatch = [];
      for (const refIris of referenceData.irisImages) {
        const compIris = comparisonData.irisImages.find((iris) => iris.position === refIris.position);
        if (compIris) {
          const irisMatch = await this.verifyIris(refIris.image, compIris.image, refIris.position);
          result.irisMatch.push(irisMatch);
          totalScore += irisMatch.score;
          matchCount++;
          if (irisMatch.matched) {
            matchCount++;
          }
        }
      }
    }

    // Calculate overall match and confidence
    const averageScore = matchCount > 0 ? totalScore / matchCount : 0;
    result.confidence = averageScore;

    // Overall match requires at least one biometric match
    result.overallMatch =
      (result.faceMatch?.matched || false) ||
      (result.fingerprintMatch?.some((fp) => fp.matched) || false) ||
      (result.irisMatch?.some((iris) => iris.matched) || false);

    return result;
  }

  /**
   * Calculate image similarity (placeholder)
   * In production, use proper image comparison algorithms
   */
  private calculateImageSimilarity(_image1: Buffer, _image2: Buffer): number {
    // Placeholder: return random score between 0.5 and 1.0
    // In production, use actual image comparison (e.g., perceptual hash, feature matching)
    return 0.5 + Math.random() * 0.5;
  }

  /**
   * Set match thresholds
   */
  setThresholds(face?: number, fingerprint?: number, iris?: number): void {
    if (face !== undefined) {
      this.faceMatchThreshold = face;
    }
    if (fingerprint !== undefined) {
      this.fingerprintMatchThreshold = fingerprint;
    }
    if (iris !== undefined) {
      this.irisMatchThreshold = iris;
    }
  }
}

/**
 * Verify biometrics from EU-LP chip data
 */
export async function verifyEULPBiometrics(
  chipData: {
    dg2?: { faceImage: Buffer };
    dg3?: { fingerprints: Array<{ fingerPosition: number; fingerprintImage: Buffer }> };
    dg4?: { irisImages: Array<{ eyePosition: number; irisImage: Buffer }> };
  },
  comparisonData: BiometricData
): Promise<BiometricVerificationResult> {
  const verifier = new BiometricVerifier();

  const referenceData: BiometricData = {
    faceImage: chipData.dg2?.faceImage,
    fingerprints: chipData.dg3?.fingerprints.map((fp) => ({
      position: fp.fingerPosition,
      image: fp.fingerprintImage,
    })),
    irisImages: chipData.dg4?.irisImages.map((iris) => ({
      position: iris.eyePosition,
      image: iris.irisImage,
    })),
  };

  return verifier.verifyBiometrics(referenceData, comparisonData);
}

