package main

import (
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"strconv"
	"time"

	"github.com/julienschmidt/httprouter"
)

func init() {
	router.GET("/api/surveys", apiAuthHandler(
		func(u *User, _ httprouter.Params, _ []byte) HTTPResponse {
			if u == nil {
				return formatApiResponse(getSurveys(fmt.Sprintf("WHERE shown = TRUE AND NOW() > start_availability AND promo = %d ORDER BY start_availability ASC", currentPromo)))
			} else if u.IsAdmin {
				return formatApiResponse(getSurveys("ORDER BY promo DESC, start_availability ASC"))
			} else {
				return formatApiResponse(getSurveys(fmt.Sprintf("WHERE shown = TRUE AND promo = %d  ORDER BY start_availability ASC", u.Promo)))
			}
		}))
	router.POST("/api/surveys", apiHandler(func(_ httprouter.Params, body []byte) HTTPResponse {
		var new Survey
		if err := json.Unmarshal(body, &new); err != nil {
			return APIErrorResponse{err: err}
		}

		if new.Promo == 0 {
			new.Promo = currentPromo
		}

		return formatApiResponse(NewSurvey(new.Title, new.Promo, new.Shown, new.StartAvailability, new.EndAvailability))
	}, adminRestricted))
	router.GET("/api/surveys/:sid", apiAuthHandler(surveyAuthHandler(
		func(s Survey, u *User, _ []byte) HTTPResponse {
			if (s.Promo == u.Promo && s.Shown) || (u != nil && u.IsAdmin) {
				return APIResponse{s}
			} else {
				return APIErrorResponse{
					status: http.StatusForbidden,
					err:    errors.New("Not accessible"),
				}
			}
		})))
	router.PUT("/api/surveys/:sid", apiHandler(surveyHandler(func(current Survey, body []byte) HTTPResponse {
		var new Survey
		if err := json.Unmarshal(body, &new); err != nil {
			return APIErrorResponse{err: err}
		}

		new.Id = current.Id
		return formatApiResponse(new.Update())
	}), adminRestricted))
	router.DELETE("/api/surveys/:sid", apiHandler(surveyHandler(
		func(s Survey, _ []byte) HTTPResponse {
			return formatApiResponse(s.Delete())
		}), adminRestricted))
	router.GET("/api/surveys/:sid/score", apiAuthHandler(surveyAuthHandler(
		func(s Survey, u *User, _ []byte) HTTPResponse {
			if (s.Promo == u.Promo && s.Shown) || (u != nil && u.IsAdmin) {
				if score, err := s.GetScore(u); err != nil {
					return APIErrorResponse{err: err}
				} else if score == nil {
					return APIResponse{map[string]string{"score": "N/A"}}
				} else {
					return APIResponse{map[string]float64{"score": *score}}
				}
			} else {
				return APIErrorResponse{
					status: http.StatusForbidden,
					err:    errors.New("Not accessible"),
				}
			}
		}), loggedUser))
	router.GET("/api/users/:uid/surveys/:sid/score", 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.Promo == u.Promo && s.Shown && u.Id == uauth.Id) || uauth.IsAdmin) {
					if score, err := s.GetScore(&u); err != nil {
						return APIErrorResponse{err: err}
					} else if score == nil {
						return APIResponse{map[string]string{"score": "N/A"}}
					} else {
						return APIResponse{map[string]float64{"score": *score}}
					}
				} else {
					return APIErrorResponse{
						status: http.StatusForbidden,
						err:    errors.New("Not accessible"),
					}
				}
			})(ps, body)
		})(uauth, ps, body)
	}, loggedUser))
}

func surveyHandler(f func(Survey, []byte) HTTPResponse) func(httprouter.Params, []byte) HTTPResponse {
	return func(ps httprouter.Params, body []byte) HTTPResponse {
		if sid, err := strconv.Atoi(string(ps.ByName("sid"))); err != nil {
			return APIErrorResponse{err: err}
		} else if survey, err := getSurvey(sid); err != nil {
			return APIErrorResponse{err: err}
		} else {
			return f(survey, body)
		}
	}
}

func surveyAuthHandler(f func(Survey, *User, []byte) HTTPResponse) func(*User, httprouter.Params, []byte) HTTPResponse {
	return func(u *User, ps httprouter.Params, body []byte) HTTPResponse {
		if sid, err := strconv.Atoi(string(ps.ByName("sid"))); err != nil {
			return APIErrorResponse{err: err}
		} else if survey, err := getSurvey(sid); err != nil {
			return APIErrorResponse{err: err}
		} else {
			return f(survey, u, body)
		}
	}
}

type Survey struct {
	Id                int64     `json:"id"`
	Title             string    `json:"title"`
	Promo             uint      `json:"promo"`
	Shown             bool      `json:"shown"`
	Corrected         bool      `json:"corrected"`
	StartAvailability time.Time `json:"start_availability"`
	EndAvailability   time.Time `json:"end_availability"`
}

func getSurveys(cnd string, param ...interface{}) (surveys []Survey, err error) {
	if rows, errr := DBQuery("SELECT id_survey, title, promo, shown, corrected, start_availability, end_availability FROM surveys "+cnd, param...); errr != nil {
		return nil, errr
	} else {
		defer rows.Close()

		for rows.Next() {
			var s Survey
			if err = rows.Scan(&s.Id, &s.Title, &s.Promo, &s.Shown, &s.Corrected, &s.StartAvailability, &s.EndAvailability); err != nil {
				return
			}
			surveys = append(surveys, s)
		}
		if err = rows.Err(); err != nil {
			return
		}

		return
	}
}

func getSurvey(id int) (s Survey, err error) {
	err = DBQueryRow("SELECT id_survey, title, promo, shown, corrected, start_availability, end_availability FROM surveys WHERE id_survey=?", id).Scan(&s.Id, &s.Title, &s.Promo, &s.Shown, &s.Corrected, &s.StartAvailability, &s.EndAvailability)
	return
}

func NewSurvey(title string, promo uint, shown bool, startAvailability time.Time, endAvailability time.Time) (Survey, error) {
	if res, err := DBExec("INSERT INTO surveys (title, promo, shown, start_availability, end_availability) VALUES (?, ?, ?, ?, ?)", title, promo, shown, startAvailability, endAvailability); err != nil {
		return Survey{}, err
	} else if sid, err := res.LastInsertId(); err != nil {
		return Survey{}, err
	} else {
		return Survey{sid, title, promo, shown, false, startAvailability, endAvailability}, nil
	}
}

func (s Survey) GetScore(u *User) (score *float64, err error) {
	err = DBQueryRow("SELECT SUM(score)/COUNT(*) FROM student_scores WHERE id_survey=? AND id_user=?", s.Id, u.Id).Scan(&score)
	if score != nil {
		*score = *score / 5.0
	}
	return
}

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

		scores = map[int64]*float64{}

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

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

	return
}

func (s Survey) Update() (int64, error) {
	if res, err := DBExec("UPDATE surveys SET title = ?, promo = ?, shown = ?, corrected = ?, start_availability = ?, end_availability = ? WHERE id_survey = ?", s.Title, s.Promo, s.Shown, s.Corrected, s.StartAvailability, s.EndAvailability, s.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

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

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