package main

import (
	"errors"
	"net/http"

	"github.com/julienschmidt/httprouter"
)

func init() {
	router.GET("/api/users/:uid/surveys/:sid/grades", apiAuthHandler(func(uauth *User, ps httprouter.Params, body []byte) HTTPResponse {
		return surveyAuthHandler(func(s Survey, uauth *User, _ []byte) HTTPResponse {
			return userHandler(func(u User, _ []byte) HTTPResponse {
				if uauth != nil && ((s.Shown && u.Id == uauth.Id) || uauth.IsAdmin) {
					if score, err := s.GetUserGrades(&u); err != nil {
						return APIErrorResponse{err: err}
					} else if score == nil {
						return APIResponse{"N/A"}
					} else {
						return APIResponse{score}
					}
				} else {
					return APIErrorResponse{
						status: http.StatusForbidden,
						err:    errors.New("Not accessible"),
					}
				}
			})(ps, body)
		})(uauth, ps, body)
	}, loggedUser))
	router.GET("/api/surveys/:sid/grades", apiAuthHandler(surveyAuthHandler(func(s Survey, uauth *User, _ []byte) HTTPResponse {
		if scores, err := s.GetGrades(); err != nil {
			return APIErrorResponse{err: err}
		} else if scores == nil {
			return APIResponse{"N/A"}
		} else {
			return APIResponse{scores}
		}
	}), adminRestricted))
	router.GET("/api/grades", apiAuthHandler(func(uauth *User, ps httprouter.Params, body []byte) HTTPResponse {
		if uauth != nil && uauth.IsAdmin {
			if score, err := GetAllGrades(); err != nil {
				return APIErrorResponse{err: err}
			} else if score == nil {
				return APIResponse{"N/A"}
			} else {
				return APIResponse{score}
			}
		} else {
			return APIErrorResponse{
				status: http.StatusForbidden,
				err:    errors.New("Not accessible"),
			}
		}
	}, adminRestricted))
}

func GetAllGrades() (scores map[int64]map[int64]*float64, err error) {
	if rows, errr := DBQuery("SELECT id_user, id_survey, SUM(score)/COUNT(*) FROM student_scores GROUP BY id_user, id_survey"); err != nil {
		return nil, errr
	} else {
		defer rows.Close()

		scores = map[int64]map[int64]*float64{}

		for rows.Next() {
			var id_user int64
			var id_survey int64
			var score *float64

			if err = rows.Scan(&id_user, &id_survey, &score); err != nil {
				return
			}

			if scores[id_user] == nil {
				scores[id_user] = map[int64]*float64{}
			}

			scores[id_user][id_survey] = score
		}
		if err = rows.Err(); err != nil {
			return
		}
	}

	return
}

func (s Survey) GetGrades() (scores map[int64]*float64, err error) {
	if rows, errr := DBQuery("SELECT id_question, SUM(score)/COUNT(*) FROM student_scores WHERE id_survey=? GROUP BY id_question", s.Id); err != nil {
		return nil, errr
	} else {
		defer rows.Close()

		scores = map[int64]*float64{}

		for rows.Next() {
			var id_question int64
			var score *float64

			if err = rows.Scan(&id_question, &score); err != nil {
				return
			}
			scores[id_question] = score
		}
		if err = rows.Err(); err != nil {
			return
		}
	}

	return
}

func (s Survey) GetUserGrades(u *User) (scores map[int64]*float64, err error) {
	if rows, errr := DBQuery("SELECT id_question, MAX(score) FROM student_scores WHERE id_survey=? AND id_user = ? GROUP BY id_question", s.Id, u.Id); err != nil {
		return nil, errr
	} else {
		defer rows.Close()

		scores = map[int64]*float64{}

		for rows.Next() {
			var id_question int64
			var score *float64

			if err = rows.Scan(&id_question, &score); err != nil {
				return
			}
			scores[id_question] = score
		}
		if err = rows.Err(); err != nil {
			return
		}
	}

	return
}