/**
 * FieldSession - Aggregate Root
 * Organizes field work. A pilot day produces many missions.
 * 
 * Invariants:
 * - Must have exactly one location
 * - Must have a date
 * - Can have zero or more missions
 * - Cannot be completed if any mission is still uploading
 */

import { SessionId, MissionId } from '../common/ids';
import { SessionStatus } from '../common/enums';
import { GeoLocation } from '../common/value-objects';
import { InvariantViolationError } from '../common/errors';

export interface FieldSession {
  readonly id: SessionId;
  readonly location: GeoLocation;
  readonly date: Date;
  readonly status: SessionStatus;
  readonly missionIds: MissionId[];
  readonly createdAt: Date;
  readonly updatedAt: Date;
}

export interface CreateSessionParams {
  readonly id: SessionId;
  readonly location: GeoLocation;
  readonly date: Date;
}

export class FieldSessionFactory {
  static create(params: CreateSessionParams): FieldSession {
    if (!params.location) {
      throw new InvariantViolationError('Session must have a location');
    }
    if (!params.date) {
      throw new InvariantViolationError('Session must have a date');
    }

    return {
      id: params.id,
      location: params.location,
      date: params.date,
      status: SessionStatus.PLANNED,
      missionIds: [],
      createdAt: new Date(),
      updatedAt: new Date()
    };
  }

  static addMission(session: FieldSession, missionId: MissionId): FieldSession {
    return {
      ...session,
      missionIds: [...session.missionIds, missionId],
      status: SessionStatus.ACTIVE,
      updatedAt: new Date()
    };
  }

  static complete(session: FieldSession): FieldSession {
    if (session.status !== SessionStatus.ACTIVE) {
      throw new InvariantViolationError('Cannot complete session that is not active');
    }

    return {
      ...session,
      status: SessionStatus.COMPLETED,
      updatedAt: new Date()
    };
  }
}