package main

import (
	"encoding/json"
	"errors"
	"time"
)

var PongSecret = "felixfixit"

func init() {
	router.GET("/api/students/:sid/ping", apiHandler(studentHandler(isPinging)))
	router.GET("/api/students/:sid/pong", apiHandler(studentHandler(func (student Student, body []byte) (interface{}, error) {
		return student.lastPongs()
	})))
	router.POST("/api/students/:sid/pong", apiHandler(studentHandler(stdPong), sslOnly))
}

func isPinging(student Student, body []byte) (interface{}, error) {
	if pongs, err := student.lastPongs(); err != nil {
		return nil, err
	} else if len(pongs) <= 0 {
		return false, nil
	} else {
		return time.Now().Before(pongs[0].Add(time.Second * 90)), nil
	}
}

func (s Student) lastPongs() (pongs []time.Time, err error) {
	if rows, errr := DBQuery("SELECT time FROM student_pong WHERE id_student = ? ORDER BY time DESC", s.Id); errr != nil {
		return nil, errr
	} else {
		defer rows.Close()

		for rows.Next() {
			var t time.Time
			if err = rows.Scan(&t); err != nil {
				return
			}
			pongs = append(pongs, t)
		}
		if err = rows.Err(); err != nil {
			return
		}

		return
	}
}

func stdPong(student Student, body []byte) (interface{}, error) {
	var gt givenToken
	if err := json.Unmarshal(body, &gt); err != nil {
		return nil, err
	}

	if gt.Token != PongSecret {
		return nil, errors.New("This is not the expected token.")
	}


	if res, err := DBExec("INSERT INTO student_pong (id_student, time) VALUES (?, ?)", student.Id, time.Now()); err != nil {
		return false, err
	} else if _, err := res.LastInsertId(); err != nil {
		return false, err
	} else {
		return true, err
	}
}