package main

import (
	"encoding/json"
	"strings"
	"time"

	"github.com/julienschmidt/httprouter"
)

func init() {
	router.GET("/api/students/", apiHandler(
		func(httprouter.Params,[]byte) (interface{}, error) {
			return getStudents() }))
	router.POST("/api/students/", apiHandler(createStudent))
}


type Student struct {
	Id    int64     `json:"id"`
	Login string    `json:"login"`
	Time  time.Time `json:"time"`
}

func getStudents() (students []Student, err error) {
	if rows, errr := DBQuery("SELECT id_student, login, time FROM students"); errr != nil {
		return nil, errr
	} else {
		defer rows.Close()

		for rows.Next() {
			var s Student
			if err = rows.Scan(&s.Id, &s.Login, &s.Time); err != nil {
				return
			}
			students = append(students, s)
		}
		if err = rows.Err(); err != nil {
			return
		}

		return
	}
}

func getStudent(id int64) (s Student, err error) {
	err = DBQueryRow("SELECT id_student, login, time FROM students WHERE id_student=?", id).Scan(&s.Id, &s.Login, &s.Time)
	return
}

func NewStudent(login string) (Student, error) {
	if res, err := DBExec("INSERT INTO students (login, time) VALUES (?, ?)", login, time.Now()); err != nil {
		return Student{}, err
	} else if sid, err := res.LastInsertId(); err != nil {
		return Student{}, err
	} else {
		return Student{sid, login, time.Now()}, nil
	}
}

func (s Student) Update() (int64, error) {
	if res, err := DBExec("UPDATE students SET login = ?, time = ? WHERE id_student = ?", s.Login, s.Time, s.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

func (s Student) Delete() (int64, error) {
	if res, err := DBExec("DELETE FROM students WHERE id_student = ?", s.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

func ClearStudents() (int64, error) {
	if res, err := DBExec("DELETE FROM students"); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}


func createStudent(_ httprouter.Params, body []byte) (interface{}, error) {
	var std Student
	if err := json.Unmarshal(body, &std); err != nil {
		return nil, err
	}

	return NewStudent(strings.TrimSpace(std.Login))
}