package main

import (
	"log"
	"net/http"

	"github.com/gin-gonic/gin"
)

func declareAPIAuthGradesRoutes(router *gin.RouterGroup) {
	router.GET("/grades", func(c *gin.Context) {
		uauth := c.MustGet("LoggedUser").(*User)

		if survey, ok := c.Get("survey"); !ok {
			if uauth == nil || !uauth.IsAdmin {
				c.AbortWithStatusJSON(http.StatusForbidden, gin.H{"errmsg": "Not authorized"})
				return
			}

			grades, err := GetAllGrades()
			if err != nil {
				log.Println("Unable to GetAllGrades:", err)
				c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": "An error occurs when trying to retrieve grades."})
				return
			}

			c.JSON(http.StatusOK, grades)
		} else {
			s := survey.(*Survey)

			if user, ok := c.Get("user"); ok {
				u := user.(*User)

				if uauth == nil || !((s.Shown && u.Id == uauth.Id) || uauth.IsAdmin) {
					c.AbortWithStatusJSON(http.StatusForbidden, gin.H{"errmsg": "Not accessible"})
					return
				}

				score, err := s.GetUserGrades(u)
				if err != nil {
					log.Printf("Unable to GetUserGrades(sid=%d; uid=%d): %s", s.Id, u.Id, err.Error())
					c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": "Unable to retrive user grade. Please try again later."})
					return
				}

				if score == nil {
					c.JSON(http.StatusOK, "N/A")
				} else {
					c.JSON(http.StatusOK, score)
				}
			} else if uauth.IsAdmin {
				scores, err := s.GetGrades()
				if err != nil {
					log.Printf("Unable to GetGrades(sid=%d): %s", s.Id, err.Error())
					c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": "Unable to retrive grades."})
					return
				}

				c.JSON(http.StatusOK, scores)
			} else {
				c.AbortWithStatusJSON(http.StatusForbidden, gin.H{"errmsg": "Not authorized"})
				return
			}
		}
	})
}

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
}