/**
 * GeoValidationService
 *
 * Service for validating geographic data in discovery locations.
 * All validation is done locally - no external API calls.
 */

import { isCoordinateValid, isWithinUS, isWithinCanada } from '../utils/GeoUtils';

export interface DiscoveryLocationGeoData {
  latitude: number | null;
  longitude: number | null;
  state_code: string | null;
  country_code: string | null;
}

export interface GeoValidationResult {
  ok: boolean;
  reason?: string;
  warnings?: string[];
}

/**
 * Simple state-to-region mapping for rough validation.
 * This is a heuristic - not precise polygon matching.
 */
const STATE_REGION_HINTS: Record<string, { latRange: [number, number]; lonRange: [number, number] }> = {
  // West Coast
  'WA': { latRange: [45.5, 49.0], lonRange: [-125, -116.9] },
  'OR': { latRange: [42.0, 46.3], lonRange: [-124.6, -116.5] },
  'CA': { latRange: [32.5, 42.0], lonRange: [-124.5, -114.1] },

  // Southwest
  'AZ': { latRange: [31.3, 37.0], lonRange: [-115, -109] },
  'NV': { latRange: [35.0, 42.0], lonRange: [-120, -114] },
  'NM': { latRange: [31.3, 37.0], lonRange: [-109, -103] },
  'UT': { latRange: [37.0, 42.0], lonRange: [-114, -109] },

  // Mountain
  'CO': { latRange: [37.0, 41.0], lonRange: [-109, -102] },
  'WY': { latRange: [41.0, 45.0], lonRange: [-111, -104] },
  'MT': { latRange: [45.0, 49.0], lonRange: [-116, -104] },
  'ID': { latRange: [42.0, 49.0], lonRange: [-117, -111] },

  // Midwest
  'MI': { latRange: [41.7, 48.3], lonRange: [-90.5, -82.4] },
  'IL': { latRange: [37.0, 42.5], lonRange: [-91.5, -87.0] },
  'OH': { latRange: [38.4, 42.0], lonRange: [-84.8, -80.5] },
  'MO': { latRange: [36.0, 40.6], lonRange: [-95.8, -89.1] },

  // Northeast
  'NY': { latRange: [40.5, 45.0], lonRange: [-79.8, -71.9] },
  'MA': { latRange: [41.2, 42.9], lonRange: [-73.5, -69.9] },
  'PA': { latRange: [39.7, 42.3], lonRange: [-80.5, -74.7] },
  'NJ': { latRange: [38.9, 41.4], lonRange: [-75.6, -73.9] },

  // Southeast
  'FL': { latRange: [24.5, 31.0], lonRange: [-87.6, -80.0] },
  'GA': { latRange: [30.4, 35.0], lonRange: [-85.6, -80.8] },
  'TX': { latRange: [25.8, 36.5], lonRange: [-106.6, -93.5] },
  'NC': { latRange: [34.0, 36.6], lonRange: [-84.3, -75.5] },

  // Alaska & Hawaii
  'AK': { latRange: [51.0, 72.0], lonRange: [-180, -130] },
  'HI': { latRange: [18.5, 22.5], lonRange: [-161, -154] },

  // Canadian provinces (rough)
  'ON': { latRange: [41.7, 57.0], lonRange: [-95.2, -74.3] },
  'BC': { latRange: [48.3, 60.0], lonRange: [-139, -114.0] },
  'AB': { latRange: [49.0, 60.0], lonRange: [-120, -110] },
  'QC': { latRange: [45.0, 62.6], lonRange: [-79.8, -57.1] },
};

export class GeoValidationService {
  /**
   * Validate a discovery location's geographic data.
   *
   * @param location Discovery location data with lat/lng and state/country codes
   * @returns Validation result with ok status and optional reason/warnings
   */
  validateLocationState(location: DiscoveryLocationGeoData): GeoValidationResult {
    const warnings: string[] = [];

    // Check if coordinates exist
    if (location.latitude === null || location.longitude === null) {
      return {
        ok: true, // Not a failure - just no coordinates to validate
        reason: 'No coordinates available for validation',
      };
    }

    // Check basic coordinate validity
    if (!isCoordinateValid(location.latitude, location.longitude)) {
      return {
        ok: false,
        reason: `Invalid coordinates: lat=${location.latitude}, lon=${location.longitude}`,
      };
    }

    const lat = location.latitude;
    const lon = location.longitude;

    // Check country code consistency
    if (location.country_code === 'US') {
      if (!isWithinUS(lat, lon)) {
        return {
          ok: false,
          reason: `Coordinates (${lat}, ${lon}) are outside US bounds but country_code is US`,
        };
      }
    } else if (location.country_code === 'CA') {
      if (!isWithinCanada(lat, lon)) {
        return {
          ok: false,
          reason: `Coordinates (${lat}, ${lon}) are outside Canada bounds but country_code is CA`,
        };
      }
    }

    // Check state code consistency (if we have a hint for this state)
    if (location.state_code) {
      const hint = STATE_REGION_HINTS[location.state_code];
      if (hint) {
        const [minLat, maxLat] = hint.latRange;
        const [minLon, maxLon] = hint.lonRange;

        // Allow some tolerance (coordinates might be near borders)
        const tolerance = 0.5; // degrees

        if (
          lat < minLat - tolerance ||
          lat > maxLat + tolerance ||
          lon < minLon - tolerance ||
          lon > maxLon + tolerance
        ) {
          warnings.push(
            `Coordinates (${lat.toFixed(4)}, ${lon.toFixed(4)}) may not match state ${location.state_code} ` +
            `(expected lat: ${minLat}-${maxLat}, lon: ${minLon}-${maxLon})`
          );
        }
      }
    }

    return {
      ok: true,
      warnings: warnings.length > 0 ? warnings : undefined,
    };
  }

  /**
   * Batch validate multiple locations.
   *
   * @param locations Array of discovery location data
   * @returns Map of validation results keyed by index
   */
  validateLocations(locations: DiscoveryLocationGeoData[]): Map<number, GeoValidationResult> {
    const results = new Map<number, GeoValidationResult>();

    locations.forEach((location, index) => {
      results.set(index, this.validateLocationState(location));
    });

    return results;
  }

  /**
   * Get a summary of validation results.
   *
   * @param results Map of validation results
   * @returns Summary with counts
   */
  summarizeValidation(results: Map<number, GeoValidationResult>): {
    total: number;
    valid: number;
    invalid: number;
    noCoordinates: number;
    withWarnings: number;
  } {
    let valid = 0;
    let invalid = 0;
    let noCoordinates = 0;
    let withWarnings = 0;

    results.forEach((result) => {
      if (!result.ok) {
        invalid++;
      } else if (result.reason?.includes('No coordinates')) {
        noCoordinates++;
      } else {
        valid++;
        if (result.warnings && result.warnings.length > 0) {
          withWarnings++;
        }
      }
    });

    return {
      total: results.size,
      valid,
      invalid,
      noCoordinates,
      withWarnings,
    };
  }
}

export default GeoValidationService;