/**
 * QUIXZOOM Area Knowledge Graph
 * 
 * Hierarkisk struktur:
 * Area (Bangkok)
 *   └── District (Sukhumvit)
 *         └── Road (Sukhumvit Road)
 *               └── Segment (Soi 22)
 *                     └── Object (Streetlight)
 *                           └── Observation
 *                                 └── Confidence
 *                                 └── Last Seen
 *                                 └── Needs Verification
 *                                 └── Knowledge Gap
 *
 * Bangkok blir bara den första regionen.
 * Samma modell fungerar i Stockholm, London, Tokyo.
 */

class AreaKnowledgeGraph {
  constructor() {
    this.areas = new Map(); // areaId -> Area
    this.objects = new Map(); // objectId -> Object (global index)
    this.observations = new Map(); // observationId -> Observation
  }

  // ============================================================
  // AREA
  // ============================================================

  createArea(config) {
    const area = {
      id: config.id || this.generateId(),
      name: config.name,
      bounds: config.bounds,
      districts: new Map(),
      statistics: {
        totalObservations: 0,
        totalObjects: 0,
        coverage: 0,
        lastUpdated: Date.now(),
      },
    };

    this.areas.set(area.id, area);
    return area;
  }

  getArea(areaId) {
    return this.areas.get(areaId);
  }

  // ============================================================
  // DISTRICT
  // ============================================================

  createDistrict(areaId, config) {
    const area = this.areas.get(areaId);
    if (!area) throw new Error(`Area not found: ${areaId}`);

    const district = {
      id: config.id || this.generateId(),
      name: config.name,
      areaId,
      bounds: config.bounds,
      roads: new Map(),
      statistics: {
        totalObservations: 0,
        totalObjects: 0,
        coverage: 0,
      },
    };

    area.districts.set(district.id, district);
    return district;
  }

  getDistrict(areaId, districtId) {
    const area = this.areas.get(areaId);
    return area?.districts.get(districtId);
  }

  // ============================================================
  // ROAD
  // ============================================================

  createRoad(areaId, districtId, config) {
    const district = this.getDistrict(areaId, districtId);
    if (!district) throw new Error(`District not found: ${districtId}`);

    const road = {
      id: config.id || this.generateId(),
      name: config.name,
      areaId,
      districtId,
      type: config.type || 'street', // street, avenue, highway, alley
      segments: new Map(),
      statistics: {
        totalObservations: 0,
        totalObjects: 0,
        length: config.length || 0,
      },
    };

    district.roads.set(road.id, road);
    return road;
  }

  // ============================================================
  // SEGMENT
  // ============================================================

  createSegment(areaId, districtId, roadId, config) {
    const road = this.getRoad(areaId, districtId, roadId);
    if (!road) throw new Error(`Road not found: ${roadId}`);

    const segment = {
      id: config.id || this.generateId(),
      name: config.name,
      areaId,
      districtId,
      roadId,
      bounds: config.bounds,
      objects: new Map(),
      observations: [],
      statistics: {
        totalObservations: 0,
        totalObjects: 0,
        coverage: 0,
        quality: 0,
      },
    };

    road.segments.set(segment.id, segment);
    return segment;
  }

  getSegment(areaId, districtId, roadId, segmentId) {
    const road = this.getRoad(areaId, districtId, roadId);
    return road?.segments.get(segmentId);
  }

  // ============================================================
  // OBJECT
  // ============================================================

  createObject(config) {
    const object = {
      id: config.id || this.generateId(),
      type: config.type, // streetlight, pothole, crosswalk, etc.
      class: config.class, // infrastructure, vehicle, vegetation, etc.
      areaId: config.areaId,
      districtId: config.districtId,
      roadId: config.roadId,
      segmentId: config.segmentId,
      location: config.location, // { lat, lng }
      firstSeen: Date.now(),
      lastSeen: Date.now(),
      observations: [],
      confidence: config.confidence || 0,
      verificationStatus: config.verificationStatus || 'unverified',
      needsVerification: config.needsVerification || false,
      attributes: config.attributes || {},
    };

    this.objects.set(object.id, object);

    // Lägg till i segment
    if (config.segmentId) {
      const segment = this.getSegment(config.areaId, config.districtId, config.roadId, config.segmentId);
      if (segment) {
        segment.objects.set(object.id, object);
      }
    }

    return object;
  }

  getObject(objectId) {
    return this.objects.get(objectId);
  }

  // ============================================================
  // OBSERVATION
  // ============================================================

  addObservation(config) {
    const observation = {
      id: config.id || this.generateId(),
      objectId: config.objectId,
      sourceType: config.sourceType, // quixzoom, youtube_cc, etc.
      sourceId: config.sourceId,
      timestamp: config.timestamp || Date.now(),
      location: config.location,
      quality: config.quality || {},
      aiAnalysis: config.aiAnalysis || {},
      reliability: config.reliability || 0,
      verificationStatus: config.verificationStatus || 'unverified',
      mediaUrl: config.mediaUrl,
      metadata: config.metadata || {},
    };

    this.observations.set(observation.id, observation);

    // Lägg till i objekt
    const object = this.objects.get(config.objectId);
    if (object) {
      object.observations.push(observation.id);
      object.lastSeen = observation.timestamp;
      
      // Uppdatera konfidens
      const allObservations = object.observations.map(id => this.observations.get(id));
      const avgConfidence = allObservations.reduce((sum, obs) => sum + (obs?.reliability || 0), 0) / allObservations.length;
      object.confidence = avgConfidence;
      
      // Markera som verifierad om tillräckligt många observationer
      if (allObservations.length >= 3 && avgConfidence > 0.7) {
        object.verificationStatus = 'verified';
        object.needsVerification = false;
      }
    }

    // Uppdatera statistik
    this.updateStatistics(config.areaId);

    return observation;
  }

  // ============================================================
  // KNOWLEDGE GAPS
  // ============================================================

  identifyKnowledgeGaps(areaId) {
    const area = this.areas.get(areaId);
    if (!area) return [];

    const gaps = [];

    // 1. Spatiala gap — områden utan observationer
    const spatialGaps = this.findSpatialGaps(area);
    gaps.push(...spatialGaps);

    // 2. Temporala gap — tider utan data
    const temporalGaps = this.findTemporalGaps(area);
    gaps.push(...temporalGaps);

    // 3. Objekt-typer med få exempel
    const categoricalGaps = this.findCategoricalGaps(area);
    gaps.push(...categoricalGaps);

    // 4. Områden med låg konfidens
    const confidenceGaps = this.findConfidenceGaps(area);
    gaps.push(...confidenceGaps);

    // 5. Objekt som behöver verifiering
    const verificationGaps = this.findVerificationGaps(area);
    gaps.push(...verificationGaps);

    return gaps.sort((a, b) => b.priority - a.priority);
  }

  findSpatialGaps(area) {
    const gaps = [];
    const gridSize = 0.001; // ~100m

    for (const district of area.districts.values()) {
      for (const road of district.roads.values()) {
        for (const segment of road.segments.values()) {
          if (segment.observations.length < 5) {
            gaps.push({
              type: 'spatial',
              subtype: 'insufficient_coverage',
              location: segment.bounds,
              description: `${segment.name} har få observationer`,
              priority: 0.7,
              suggestedAction: 'Dokumentera segmentet mer noggrant',
            });
          }
        }
      }
    }

    return gaps;
  }

  findTemporalGaps(area) {
    const gaps = [];
    const hourCounts = new Array(24).fill(0);

    for (const observation of this.observations.values()) {
      if (observation.location && this.isInArea(observation.location, area)) {
        const hour = new Date(observation.timestamp).getHours();
        hourCounts[hour]++;
      }
    }

    const avgCount = this.observations.size / 24;

    for (let hour = 0; hour < 24; hour++) {
      if (hourCounts[hour] < avgCount * 0.3) {
        gaps.push({
          type: 'temporal',
          subtype: 'missing_time_period',
          timeOfDay: hour,
          description: `Få observationer kl ${hour}:00-${hour + 1}:00`,
          priority: 0.5,
          suggestedAction: `Dokumentera området kl ${hour}:00`,
        });
      }
    }

    return gaps;
  }

  findCategoricalGaps(area) {
    const gaps = [];
    const objectTypes = new Map();

    for (const object of this.objects.values()) {
      if (object.areaId === area.id) {
        const count = objectTypes.get(object.type) || 0;
        objectTypes.set(object.type, count + 1);
      }
    }

    const avgCount = this.objects.size / objectTypes.size;

    for (const [type, count] of objectTypes) {
      if (count < avgCount * 0.2) {
        gaps.push({
          type: 'categorical',
          subtype: 'rare_object_type',
          objectType: type,
          description: `Få exempel av ${type} (${count} observationer)`,
          priority: 0.6,
          suggestedAction: `Dokumentera fler ${type}`,
        });
      }
    }

    return gaps;
  }

  findConfidenceGaps(area) {
    const gaps = [];

    for (const object of this.objects.values()) {
      if (object.areaId === area.id && object.confidence < 0.5) {
        gaps.push({
          type: 'confidence',
          subtype: 'low_confidence_object',
          objectId: object.id,
          description: `${object.type} har låg konfidens (${(object.confidence * 100).toFixed(0)}%)`,
          priority: 0.8,
          suggestedAction: 'Verifiera objektet från annan vinkel',
        });
      }
    }

    return gaps;
  }

  findVerificationGaps(area) {
    const gaps = [];

    for (const object of this.objects.values()) {
      if (object.areaId === area.id && object.needsVerification) {
        gaps.push({
          type: 'verification',
          subtype: 'needs_verification',
          objectId: object.id,
          description: `${object.type} behöver verifiering`,
          priority: 0.9,
          suggestedAction: 'Dokumentera samma objekt från annan vinkel eller tid',
        });
      }
    }

    return gaps;
  }

  // ============================================================
  // STATISTICS
  // ============================================================

  updateStatistics(areaId) {
    const area = this.areas.get(areaId);
    if (!area) return;

    let totalObservations = 0;
    let totalObjects = 0;

    for (const district of area.districts.values()) {
      for (const road of district.roads.values()) {
        for (const segment of road.segments.values()) {
          totalObservations += segment.observations.length;
          totalObjects += segment.objects.size;
        }
      }
    }

    area.statistics = {
      totalObservations,
      totalObjects,
      coverage: this.calculateCoverage(area),
      lastUpdated: Date.now(),
    };
  }

  calculateCoverage(area) {
    const uniqueLocations = new Set();

    for (const observation of this.observations.values()) {
      if (observation.location && this.isInArea(observation.location, area)) {
        const key = `${observation.location.lat.toFixed(4)},${observation.location.lng.toFixed(4)}`;
        uniqueLocations.add(key);
      }
    }

    // Förenklad: anta att 1000 unika platser är 100% täckning
    return Math.min(1.0, uniqueLocations.size / 1000);
  }

  isInArea(location, area) {
    const bounds = area.bounds;
    return location.lat >= bounds.minLat &&
           location.lat <= bounds.maxLat &&
           location.lng >= bounds.minLng &&
           location.lng <= bounds.maxLng;
  }

  // ============================================================
  // EXPORT
  // ============================================================

  exportToJSON(areaId) {
    const area = this.areas.get(areaId);
    if (!area) return null;

    const districts = [];
    for (const district of area.districts.values()) {
      const roads = [];
      for (const road of district.roads.values()) {
        const segments = [];
        for (const segment of road.segments.values()) {
          const objects = [];
          for (const object of segment.objects.values()) {
            const observations = object.observations.map(id => this.observations.get(id));
            objects.push({
              ...object,
              observations,
            });
          }
          segments.push({
            ...segment,
            objects,
          });
        }
        roads.push({
          ...road,
          segments,
        });
      }
      districts.push({
        ...district,
        roads,
      });
    }

    return {
      ...area,
      districts,
    };
  }

  // ============================================================
  // HJÄLPMETODER
  // ============================================================

  generateId() {
    return `id_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
  }

  getRoad(areaId, districtId, roadId) {
    const district = this.getDistrict(areaId, districtId);
    return district?.roads.get(roadId);
  }
}

// Exportera
module.exports = AreaKnowledgeGraph;

// Demo
if (require.main === module) {
  const graph = new AreaKnowledgeGraph();

  console.log('=== AREA KNOWLEDGE GRAPH DEMO ===\n');

  // Skapa Bangkok
  const bangkok = graph.createArea({
    name: 'Bangkok',
    bounds: { minLat: 13.5, maxLat: 14.0, minLng: 100.3, maxLng: 100.9 },
  });
  console.log(`Created area: ${bangkok.name} (${bangkok.id})`);

  // Skapa distrikt
  const sukhumvit = graph.createDistrict(bangkok.id, {
    name: 'Sukhumvit',
    bounds: { minLat: 13.7, maxLat: 13.8, minLng: 100.5, maxLng: 100.6 },
  });
  console.log(`Created district: ${sukhumvit.name}`);

  // Skapa väg
  const sukhumvitRoad = graph.createRoad(bangkok.id, sukhumvit.id, {
    name: 'Sukhumvit Road',
    type: 'avenue',
    length: 4000,
  });
  console.log(`Created road: ${sukhumvitRoad.name}`);

  // Skapa segment
  const soi22 = graph.createSegment(bangkok.id, sukhumvit.id, sukhumvitRoad.id, {
    name: 'Soi 22',
    bounds: { minLat: 13.72, maxLat: 13.73, minLng: 100.55, maxLng: 100.56 },
  });
  console.log(`Created segment: ${soi22.name}`);

  // Skapa objekt
  const streetlight = graph.createObject({
    type: 'streetlight',
    class: 'infrastructure',
    areaId: bangkok.id,
    districtId: sukhumvit.id,
    roadId: sukhumvitRoad.id,
    segmentId: soi22.id,
    location: { lat: 13.725, lng: 100.555 },
    confidence: 0.8,
    attributes: { condition: 'broken', height: 5 },
  });
  console.log(`Created object: ${streetlight.type} (${streetlight.id})`);

  // Lägg till observation
  const observation = graph.addObservation({
    objectId: streetlight.id,
    sourceType: 'quixzoom',
    location: { lat: 13.725, lng: 100.555 },
    quality: { sharpness: 0.9, exposure: 0.8 },
    aiAnalysis: { objectDetection: 0.92, condition: 'broken' },
    reliability: 0.85,
  });
  console.log(`Added observation: ${observation.id}`);

  // Identifiera kunskapsgap
  const gaps = graph.identifyKnowledgeGaps(bangkok.id);
  console.log(`\nKnowledge gaps found: ${gaps.length}`);
  for (const gap of gaps) {
    console.log(`  - ${gap.type}: ${gap.description} (priority: ${gap.priority})`);
  }

  // Exportera
  const exported = graph.exportToJSON(bangkok.id);
  console.log(`\nExported area with ${exported.districts.length} districts`);
}