import { Schema, model, Document, Types } from 'mongoose';

interface IGeoPoint {
  type: "Point";
  coordinates: [number, number]; // [lng, lat]
}

interface IEventParticipant {
  user: Types.ObjectId;
  joinedAt: Date;
  joinMethod: 'code' | 'link' | 'qr' | 'manual';
}

export interface IEvent extends Document {
  // Basic Info
  title: string;
  code: string; // Short join code (e.g., NDMA-FIRE-23)
  theme: string; // e.g., "Fire Safety", "Disaster Response"
  description?: string;

  // Organization
  organization: Types.ObjectId;
  createdBy: Types.ObjectId; // Trainer who created it

  // Capacity & Timing
  capacity: number;
  startDate: Date;
  endDate: Date;
  defaultStartTime: string; // Default session start time (e.g., "16:00")
  defaultEndTime: string; // Default session end time (e.g., "18:00")

  // Type & Location
  type: 'in-person' | 'online' | 'hybrid';
  venue?: string; // Physical address for in-person/hybrid
  location?: IGeoPoint; // Geo coordinates for in-person/hybrid
  geofenceRadius?: number; // Meters - for GPS check-in
  onlineLink?: string; // Meeting link for online/hybrid

  // Join Settings
  joinToken: string; // Secret token for join links
  allowSelfJoin: boolean; // Can trainees join without approval?

  // Participants
  participants: IEventParticipant[];
  waitlist: Types.ObjectId[]; // If capacity is full

  // Status
  status: 'draft' | 'published' | 'ongoing' | 'completed' | 'cancelled';

  // Notifications
  reminderSent: boolean;

  // Metadata
  createdAt: Date;
  updatedAt: Date;
}

const EventSchema = new Schema<IEvent>({
  title: {
    type: String,
    required: true,
    trim: true,
    index: 'text' // For text search
  },

  code: {
    type: String,
    required: true,
    unique: true,
    uppercase: true,
    trim: true,
    index: true
  },

  theme: {
    type: String,
    required: true,
    index: true
  },

  description: {
    type: String,
    trim: true
  },

  organization: {
    type: Schema.Types.ObjectId,
    ref: 'User',
    required: true,
    index: true
  },

  createdBy: {
    type: Schema.Types.ObjectId,
    ref: 'User',
    required: true,
    index: true
  },

  capacity: {
    type: Number,
    required: true,
    min: 1
  },

  startDate: {
    type: Date,
    required: true,
    index: true
  },

  endDate: {
    type: Date,
    required: true,
    index: true
  },

  defaultStartTime: {
    type: String,
    required: true,
    match: /^([0-1]?[0-9]|2[0-3]):[0-5][0-9]$/ // HH:MM format
  },

  defaultEndTime: {
    type: String,
    required: true,
    match: /^([0-1]?[0-9]|2[0-3]):[0-5][0-9]$/ // HH:MM format
  },

  type: {
    type: String,
    enum: ['in-person', 'online', 'hybrid'],
    required: true,
    index: true
  },

  venue: {
    type: String,
    trim: true
  },

  location: {
    type: {
      type: String,
      enum: ['Point'],
      default: 'Point'
    },
    coordinates: {
      type: [Number], // [lng, lat]
      validate: {
        validator: function (v: number[]) {
          return v.length === 2 &&
            v[0] >= -180 && v[0] <= 180 &&
            v[1] >= -90 && v[1] <= 90;
        },
        message: 'Invalid coordinates'
      }
    }
  },

  geofenceRadius: {
    type: Number,
    default: 100, // 100 meters default
    min: 10,
    max: 5000
  },

  onlineLink: {
    type: String,
    trim: true
  },

  joinToken: {
    type: String,
    required: true,
    index: true
  },

  allowSelfJoin: {
    type: Boolean,
    default: true
  },

  participants: [{
    user: {
      type: Schema.Types.ObjectId,
      ref: 'User',
      required: true
    },
    joinedAt: {
      type: Date,
      default: Date.now
    },
    joinMethod: {
      type: String,
      enum: ['code', 'link', 'qr', 'manual'],
      required: true
    }
  }],

  waitlist: [{
    type: Schema.Types.ObjectId,
    ref: 'User'
  }],

  status: {
    type: String,
    enum: ['draft', 'published', 'ongoing', 'completed', 'cancelled'],
    default: 'draft',
    index: true
  },

  reminderSent: {
    type: Boolean,
    default: false
  }
}, {
  timestamps: true
});

// Indexes
EventSchema.index({ location: '2dsphere' }); // For geospatial queries
EventSchema.index({ startDate: 1, status: 1 }); // For upcoming events
EventSchema.index({ organization: 1, status: 1 }); // Org events
EventSchema.index({ 'participants.user': 1 }); // User's events

// Text search on title and theme
EventSchema.index({ title: 'text', theme: 'text', description: 'text' });

// Validation: endDate must be after startDate
EventSchema.pre('save', function (this: IEvent) {
  if (this.endDate <= this.startDate) {
    throw new Error('End date must be after start date');
  }
});

// Auto-generate EventDay records when event is created
EventSchema.post('save', async function (doc: IEvent) {
  const { generateEventDays } = await import('../util/eventDay.util');

  // Check if this is a new document (not an update)
  if (this.isNew) {
    try {
      await generateEventDays(doc);
    } catch (err) {
      console.error('Failed to generate event days:', err);
    }
  }
});

export default model<IEvent>('Event', EventSchema);