import { DateHelper } from "../../../../browser/date/DateHelper";
import { DateMath } from "../../../../browser/date/DateMath";
import { ISOTimeStamp } from "../../../../browser/date/ISOTimeStamp";
import { PathReference } from "../../../files/PathReference";
import { iTaskScheduler } from "../../scheduler/iTaskScheduler";
import { Task } from "../../scheduler/Task";
import { UserData } from "../../UserData";
import { UserManagementServer } from "../../UserManagementServer";
import { UserApp } from "../UserApp";
import { MailEntry } from "./data/MailEntry";
import { ReminderData } from "./data/ReminderData";

export class ReminderApp extends UserApp<ReminderData> implements iTaskScheduler
{ 
  static readonly id = "reminder";
  
  constructor( ums:UserManagementServer )
  { 
    super( ReminderApp.id, ums );
    this.onFileChange.addListener(
      async ( filePath )=>
      {
        let pathReference = new PathReference( filePath );
        let id = pathReference.fileNameWithoutExtension;
        let user = await this.ums.userDB.byID( id );

        if ( ! user )
        {
          console.log( "file changed:", filePath, "but no user associated" );
          return;
        }

        let data = await pathReference.loadJSON<ReminderData>();

        let tasks:Task[] =[]; 
        this.grabTasks( user, data, this.ums.scheduler.maxDate, tasks );
        this.ums.scheduler.scheduleTasks( tasks );
        
      }
    )
  } 

  async getTasksToSchedule( maxDate:Date ):Promise<Task[]>
  {
    let tasks = [];

    await this.iterateUserData( 
      ( userData:UserData, reminderData:ReminderData )=>
      {
        this.grabTasks( userData, reminderData, maxDate, tasks );
        return Promise.resolve();
      }
    );

    return Promise.resolve( tasks );
  }

  grabTasks( userData:UserData, rd:ReminderData, maxDate:Date, tasks:Task[] )
  {
    rd.mailEntries.forEach(
      ( me )=>
      {
        let date = DateHelper.parseDateExpression( me.date );
        
        if ( DateMath.isBefore( date, maxDate ) )
        {
          let task = Task.createAt( me.id, date, 
            ()=>
            {
              this.ums.sendEmail( userData.email, me.subject, me.message );
            } 
          );

          task.setUserContext( this.id, userData.id );
          tasks.push( task )
        }  
      }
    );
  }
}