import {
  Address,
  MatchResult,
  MatchDetails,
  FieldMatch,
  MatchingConfig,
  NormalizedTokens,
  PropertyType,
} from './types';

const DEFAULT_CONFIG: MatchingConfig = {
  nameThreshold: 0.85,
  addressThreshold: 0.9,
  overallThreshold: 0.85,
  geocodingRadiusMeters: 100,
};

const COMMON_PREFIXES = new Set([
  'mr', 'mrs', 'ms', 'miss', 'dr', 'prof', 'jr', 'sr', 'junior', 'senior',
  'ii', 'iii', 'iv', 'rev', 'st', 'hon', 'esq',
]);

const COMMON_SUFFIXES = new Set([
  'jr', 'sr', 'junior', 'senior', 'ii', 'iii', 'iv', 'v', 'esq',
  'phd', 'md', 'llm', 'cpa',
]);

const STREET_TYPE_MAP: Record<string, string> = {
  'st': 'street', 'street': 'street',
  'ave': 'avenue', 'avenue': 'avenue',
  'blvd': 'boulevard', 'boulevard': 'boulevard',
  'dr': 'drive', 'drive': 'drive',
  'ln': 'lane', 'lane': 'lane',
  'ct': 'court', 'court': 'court',
  'pl': 'place', 'place': 'place',
  'rd': 'road', 'road': 'road',
  'way': 'way',
  'trl': 'trail', 'trail': 'trail',
  'hwy': 'highway', 'highway': 'highway',
  'pkwy': 'parkway', 'parkway': 'parkway',
  'cir': 'circle', 'circle': 'circle',
  'sq': 'square', 'square': 'square',
  'ter': 'terrace', 'terrace': 'terrace',
};

const PROPERTY_TYPE_CONFIGS: Record<PropertyType, Partial<MatchingConfig>> = {
  'residential': { nameThreshold: 0.85, addressThreshold: 0.9 },
  'commercial': { nameThreshold: 0.8, addressThreshold: 0.9 },
  'land': { nameThreshold: 0.8, addressThreshold: 0.85 },
  'multi-family': { nameThreshold: 0.8, addressThreshold: 0.9 },
};

function levenshteinDistance(a: string, b: string): number {
  const matrix: number[][] = Array.from({ length: b.length + 1 }, (_, i) =>
    Array.from({ length: a.length + 1 }, (_, j) => (i === 0 ? j : j === 0 ? i : 0))
  );

  for (let i = 1; i <= b.length; i++) {
    for (let j = 1; j <= a.length; j++) {
      const cost = a[j - 1] === b[i - 1] ? 0 : 1;
      matrix[i][j] = Math.min(
        matrix[i - 1][j] + 1,
        matrix[i][j - 1] + 1,
        matrix[i - 1][j - 1] + cost,
      );
    }
  }

  return matrix[b.length][a.length];
}

function similarityScore(distance: number, maxLen: number): number {
  if (maxLen === 0) return 1.0;
  return 1.0 - distance / maxLen;
}

function normalizeString(str: string): string {
  return str
    .toLowerCase()
    .replace(/[''']/g, '')
    .replace(/[^a-z0-9\s]/g, ' ')
    .replace(/\s+/g, ' ')
    .trim();
}

function parseName(name: string): NormalizedTokens {
  const clean = normalizeString(name);
  const parts = clean.split(' ').filter(Boolean);

  let firstName = '';
  let lastName = '';
  let middleName = '';
  const initials: string[] = [];

  if (parts.length === 0) return { firstName, lastName, middleName, initials };

  let startIdx = 0;
  while (startIdx < parts.length && COMMON_PREFIXES.has(parts[startIdx])) {
    startIdx++;
  }

  let endIdx = parts.length;
  while (endIdx > startIdx + 1 && COMMON_SUFFIXES.has(parts[endIdx - 1])) {
    endIdx--;
  }

  const coreParts = parts.slice(startIdx, endIdx);

  if (coreParts.length === 1) {
    lastName = coreParts[0];
  } else if (coreParts.length === 2) {
    firstName = coreParts[0];
    lastName = coreParts[1];
  } else {
    firstName = coreParts[0];
    lastName = coreParts[coreParts.length - 1];
    middleName = coreParts.slice(1, -1).join(' ');
  }

  if (firstName.length === 1) {
    initials.push(firstName);
  }
  if (middleName) {
    const middleParts = middleName.split(' ');
    for (const mp of middleParts) {
      if (mp.length === 1) initials.push(mp);
    }
  }

  return { firstName, lastName, middleName, initials };
}

function normalizeStreetType(type: string): string {
  const clean = normalizeString(type);
  return STREET_TYPE_MAP[clean] || clean;
}

function normalizeAddress(addr: Address): string {
  const parts = [
    addr.streetNumber,
    normalizeString(addr.streetName),
    addr.streetType ? normalizeStreetType(addr.streetType) : '',
    addr.unit ? normalizeString(addr.unit) : '',
    normalizeString(addr.city),
    addr.state.toLowerCase(),
    addr.zip,
  ].filter(Boolean);
  return parts.join(' ');
}

function computeFieldMatch(valueA: string, valueB: string, normalizeFn?: (v: string) => string): FieldMatch {
  const normFn = normalizeFn || normalizeString;
  const normalizedA = normFn(valueA);
  const normalizedB = normFn(valueB);

  if (!normalizedA && !normalizedB) return { valueA, valueB, normalizedA, normalizedB, score: 1.0 };
  if (!normalizedA || !normalizedB) return { valueA, valueB, normalizedA, normalizedB, score: 0.0 };

  if (normalizedA === normalizedB) return { valueA, valueB, normalizedA, normalizedB, score: 1.0 };

  const dist = levenshteinDistance(normalizedA, normalizedB);
  const maxLen = Math.max(normalizedA.length, normalizedB.length);
  const score = similarityScore(dist, maxLen);

  return { valueA, valueB, normalizedA, normalizedB, score: Math.round(score * 1000) / 1000 };
}

function haversineDistance(lat1: number, lon1: number, lat2: number, lon2: number): number {
  const R = 6371000;
  const dLat = ((lat2 - lat1) * Math.PI) / 180;
  const dLon = ((lon2 - lon1) * Math.PI) / 180;
  const a =
    Math.sin(dLat / 2) * Math.sin(dLat / 2) +
    Math.cos((lat1 * Math.PI) / 180) *
      Math.cos((lat2 * Math.PI) / 180) *
      Math.sin(dLon / 2) *
      Math.sin(dLon / 2);
  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
  return R * c;
}

function computeNameScore(tokensA: NormalizedTokens, tokensB: NormalizedTokens): number {
  const firstScore = computeFieldMatch(tokensA.firstName, tokensB.firstName).score;
  const lastScore = computeFieldMatch(tokensA.lastName, tokensB.lastName).score;
  const middleScore = computeFieldMatch(tokensA.middleName, tokensB.middleName).score;

  let initialMatchScore = 1.0;
  if (tokensA.initials.length > 0 || tokensB.initials.length > 0) {
    const allInitialsA = new Set(tokensA.initials.map(i => i.toLowerCase()));
    const allInitialsB = new Set(tokensB.initials.map(i => i.toLowerCase()));
    let matched = 0;
    for (const init of allInitialsA) {
      if (allInitialsB.has(init)) matched++;
    }
    const total = Math.max(allInitialsA.size, allInitialsB.size);
    initialMatchScore = total > 0 ? matched / total : 1.0;
  }

  const weighted = (lastScore * 0.45) + (firstScore * 0.35) + (middleScore * 0.1) + (initialMatchScore * 0.1);
  return Math.round(weighted * 1000) / 1000;
}

function computeAddressScore(addrA: Address, addrB: Address, config: MatchingConfig): { score: number; geocodingDistance?: number } {
  const numberMatch = computeFieldMatch(addrA.streetNumber, addrB.streetNumber).score;
  const streetMatch = computeFieldMatch(addrA.streetName, addrB.streetName, normalizeString).score;
  const typeMatch = computeFieldMatch(
    addrA.streetType ? normalizeStreetType(addrA.streetType) : '',
    addrB.streetType ? normalizeStreetType(addrB.streetType) : '',
  ).score;
  const unitMatch = computeFieldMatch(addrA.unit || '', addrB.unit || '').score;
  const cityMatch = computeFieldMatch(addrA.city, addrB.city).score;
  const stateMatch = computeFieldMatch(addrA.state, addrB.state).score;
  const zipMatch = computeFieldMatch(addrA.zip, addrB.zip).score;

  let geocodingDistance: number | undefined;
  let geoScore = 0.0;

  if (addrA.latitude && addrA.longitude && addrB.latitude && addrB.longitude) {
    geocodingDistance = haversineDistance(addrA.latitude, addrA.longitude, addrB.latitude, addrB.longitude);
    const maxDist = config.geocodingRadiusMeters;
    geoScore = geocodingDistance <= maxDist ? 1.0 : Math.max(0, 1.0 - (geocodingDistance - maxDist) / (maxDist * 5));
  }

  const weighted =
    (numberMatch * 0.2) +
    (streetMatch * 0.25) +
    (typeMatch * 0.1) +
    (unitMatch * 0.1) +
    (cityMatch * 0.1) +
    (stateMatch * 0.1) +
    (zipMatch * 0.1) +
    (geoScore * (geocodingDistance !== undefined ? 0.05 : 0));

  return { score: Math.round(weighted * 1000) / 1000, geocodingDistance };
}

export function matchRecords(
  nameA: string,
  addressA: Address,
  nameB: string,
  addressB: Address,
  config?: Partial<MatchingConfig>,
): MatchResult {
  const effectiveConfig = { ...DEFAULT_CONFIG, ...config };

  const tokensA = parseName(nameA);
  const tokensB = parseName(nameB);

  const nameScore = computeNameScore(tokensA, tokensB);

  const { score: addressScore, geocodingDistance } = computeAddressScore(addressA, addressB, effectiveConfig);

  const overallConfidence = Math.round((nameScore * 0.5 + addressScore * 0.5) * 1000) / 1000;

  const firstMatch = computeFieldMatch(tokensA.firstName, tokensB.firstName);
  const lastMatch = computeFieldMatch(tokensA.lastName, tokensB.lastName);
  const middleMatch = computeFieldMatch(tokensA.middleName, tokensB.middleName);
  const numberMatch = computeFieldMatch(addressA.streetNumber, addressB.streetNumber);
  const streetMatch = computeFieldMatch(addressA.streetName, addressB.streetName, normalizeString);
  const typeMatch = computeFieldMatch(
    addressA.streetType ? normalizeStreetType(addressA.streetType) : '',
    addressB.streetType ? normalizeStreetType(addressB.streetType) : '',
  );
  const unitMatch = computeFieldMatch(addressA.unit || '', addressB.unit || '');
  const cityMatch = computeFieldMatch(addressA.city, addressB.city);
  const stateMatch = computeFieldMatch(addressA.state, addressB.state);
  const zipMatch = computeFieldMatch(addressA.zip, addressB.zip);

  const normalizedA = normalizeAddress(addressA);
  const normalizedB = normalizeAddress(addressB);

  const dist = levenshteinDistance(
    normalizeString(nameA),
    normalizeString(nameB),
  );

  const details: MatchDetails = {
    nameNormalized: [normalizeString(nameA), normalizeString(nameB)],
    addressNormalized: [normalizedA, normalizedB],
    levenshteinDistance: dist,
    geocodingDistance,
    fields: {
      firstName: firstMatch,
      lastName: lastMatch,
      middleName: middleMatch,
      streetNumber: numberMatch,
      streetName: streetMatch,
      streetType: typeMatch,
      unit: unitMatch,
      city: cityMatch,
      state: stateMatch,
      zip: zipMatch,
    },
  };

  return {
    nameScore,
    addressScore,
    overallConfidence,
    isMatch: overallConfidence >= effectiveConfig.overallThreshold,
    details,
  };
}

export function getConfigForPropertyType(type: PropertyType): MatchingConfig {
  return { ...DEFAULT_CONFIG, ...PROPERTY_TYPE_CONFIGS[type] };
}

export { parseName, normalizeString, normalizeStreetType, levenshteinDistance, similarityScore };