package main

import (
	"encoding/json"
	"strconv"
	"strings"

	"github.com/julienschmidt/httprouter"
)

func init() {
	router.GET("/api/surveys/:sid/questions/:qid/corrections", apiHandler(questionHandler(
		func(q Question, _ []byte) HTTPResponse {
			if cts, err := q.GetCorrectionTemplates(); err != nil {
				return APIErrorResponse{err: err}
			} else {
				return APIResponse{cts}
			}
		}), adminRestricted))
	router.POST("/api/surveys/:sid/questions/:qid/corrections", apiHandler(questionHandler(func(q Question, body []byte) HTTPResponse {
		var new CorrectionTemplate
		if err := json.Unmarshal(body, &new); err != nil {
			return APIErrorResponse{err: err}
		}

		return formatApiResponse(q.NewCorrectionTemplate(new.Label, new.Score, new.ScoreExplaination))
	}), adminRestricted))

	router.GET("/api/surveys/:sid/questions/:qid/corrections/:cid", apiHandler(correctionHandler(
		func(ct CorrectionTemplate, _ []byte) HTTPResponse {
			if users, err := ct.GetUserCorrected(); err != nil {
				return APIErrorResponse{err: err}
			} else {
				return APIResponse{users}
			}
		}), adminRestricted))
	router.PUT("/api/surveys/:sid/questions/:qid/corrections/:cid", apiHandler(correctionHandler(func(current CorrectionTemplate, body []byte) HTTPResponse {
		var new CorrectionTemplate
		if err := json.Unmarshal(body, &new); err != nil {
			return APIErrorResponse{err: err}
		}

		new.Id = current.Id
		if err := new.Update(); err != nil {
			return APIErrorResponse{err: err}
		} else {
			return APIResponse{new}
		}
	}), adminRestricted))
	router.DELETE("/api/surveys/:sid/questions/:qid/corrections/:cid", apiHandler(correctionHandler(func(ct CorrectionTemplate, body []byte) HTTPResponse {
		return formatApiResponse(ct.Delete())
	}), adminRestricted))

	router.GET("/api/users/:uid/questions/:qid", apiAuthHandler(func(u *User, ps httprouter.Params, body []byte) HTTPResponse {
		return userHandler(func(u User, _ []byte) HTTPResponse {
			if qid, err := strconv.Atoi(string(ps.ByName("qid"))); err != nil {
				return APIErrorResponse{err: err}
			} else if question, err := getQuestion(qid); err != nil {
				return APIErrorResponse{err: err}
			} else {
				return formatApiResponse(question.ComputeScoreQuestion(&u))
			}
		})(ps, body)
	}, adminRestricted))

	router.GET("/api/users/:uid/corrections", apiHandler(userHandler(
		func(u User, _ []byte) HTTPResponse {
			return formatApiResponse(u.GetCorrections())
		}), adminRestricted))
	router.POST("/api/users/:uid/corrections", apiHandler(userHandler(func(u User, body []byte) HTTPResponse {
		var new UserCorrection
		if err := json.Unmarshal(body, &new); err != nil {
			return APIErrorResponse{err: err}
		}

		return formatApiResponse(u.NewCorrection(new.IdTemplate))
	}), adminRestricted))
	router.DELETE("/api/users/:uid/corrections/:cid", apiHandler(userCorrectionHandler(func(u User, uc UserCorrection, body []byte) HTTPResponse {
		return formatApiResponse(uc.Delete(u))
	}), adminRestricted))
}

func correctionHandler(f func(CorrectionTemplate, []byte) HTTPResponse) func(httprouter.Params, []byte) HTTPResponse {
	return func(ps httprouter.Params, body []byte) HTTPResponse {
		return questionHandler(func(q Question, body []byte) HTTPResponse {
			if cid, err := strconv.Atoi(string(ps.ByName("cid"))); err != nil {
				return APIErrorResponse{err: err}
			} else if correction, err := q.GetCorrectionTemplate(cid); err != nil {
				return APIErrorResponse{err: err}
			} else {
				return f(correction, body)
			}
		})(ps, body)
	}
}

func userCorrectionHandler(f func(User, UserCorrection, []byte) HTTPResponse) func(httprouter.Params, []byte) HTTPResponse {
	return func(ps httprouter.Params, body []byte) HTTPResponse {
		return userHandler(func(u User, body []byte) HTTPResponse {
			if cid, err := strconv.Atoi(string(ps.ByName("cid"))); err != nil {
				return APIErrorResponse{err: err}
			} else if correction, err := u.GetCorrection(cid); err != nil {
				return APIErrorResponse{err: err}
			} else {
				return f(u, correction, body)
			}
		})(ps, body)
	}
}

type CorrectionTemplate struct {
	Id                int64  `json:"id"`
	IdQuestion        int64  `json:"id_question"`
	Label             string `json:"label"`
	Score             int    `json:"score"`
	ScoreExplaination string `json:"score_explaination,omitempty"`
}

func (q *Question) GetCorrectionTemplates() (ct []CorrectionTemplate, err error) {
	if rows, errr := DBQuery("SELECT id_template, id_question, label, score, score_explanation FROM correction_templates WHERE id_question=?", q.Id); errr != nil {
		return nil, errr
	} else {
		defer rows.Close()

		for rows.Next() {
			var c CorrectionTemplate
			if err = rows.Scan(&c.Id, &c.IdQuestion, &c.Label, &c.Score, &c.ScoreExplaination); err != nil {
				return
			}
			ct = append(ct, c)
		}
		if err = rows.Err(); err != nil {
			return
		}

		return
	}
}

func (q *Question) GetCorrectionTemplate(id int) (c CorrectionTemplate, err error) {
	err = DBQueryRow("SELECT id_template, id_question, label, score, score_explanation FROM correction_templates WHERE id_question=? AND id_template=?", q.Id, id).Scan(&c.Id, &c.IdQuestion, &c.Label, &c.Score, &c.ScoreExplaination)
	return
}

func GetCorrectionTemplate(id int64) (c CorrectionTemplate, err error) {
	err = DBQueryRow("SELECT id_template, id_question, label, score, score_explanation FROM correction_templates WHERE id_template=?", id).Scan(&c.Id, &c.IdQuestion, &c.Label, &c.Score, &c.ScoreExplaination)
	return
}

func (q *Question) NewCorrectionTemplate(label string, score int, score_explaination string) (CorrectionTemplate, error) {
	if res, err := DBExec("INSERT INTO correction_templates (id_question, label, score, score_explanation) VALUES (?, ?, ?, ?)", q.Id, label, score, score_explaination); err != nil {
		return CorrectionTemplate{}, err
	} else if cid, err := res.LastInsertId(); err != nil {
		return CorrectionTemplate{}, err
	} else {
		return CorrectionTemplate{cid, q.Id, label, score, score_explaination}, nil
	}
}

func (t *CorrectionTemplate) Update() error {
	_, err := DBExec("UPDATE correction_templates SET id_question = ?, label = ?, score = ?, score_explanation = ? WHERE id_template = ?", t.IdQuestion, t.Label, t.Score, t.ScoreExplaination, t.Id)
	return err
}

func (t *CorrectionTemplate) Delete() (int64, error) {
	if res, err := DBExec("DELETE FROM correction_templates WHERE id_template = ?", t.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

func (t *CorrectionTemplate) GetUserCorrected() (ucs []UserCorrection, err error) {
	if rows, errr := DBQuery("SELECT id_correction, id_user, id_template FROM student_corrected WHERE id_template=?", t.Id); errr != nil {
		return nil, errr
	} else {
		defer rows.Close()

		for rows.Next() {
			var c UserCorrection
			if err = rows.Scan(&c.Id, &c.IdUser, &c.IdTemplate); err != nil {
				return
			}
			ucs = append(ucs, c)
		}
		if err = rows.Err(); err != nil {
			return
		}

		return
	}
}

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

type UserCorrection struct {
	Id         int64 `json:"id"`
	IdUser     int64 `json:"id_user,omitempty"`
	IdTemplate int64 `json:"id_template"`
}

func (u *User) GetCorrections() (uc []UserCorrection, err error) {
	if rows, errr := DBQuery("SELECT id_correction, id_template FROM student_corrected WHERE id_user=?", u.Id); errr != nil {
		return nil, errr
	} else {
		defer rows.Close()

		for rows.Next() {
			var c UserCorrection
			if err = rows.Scan(&c.Id, &c.IdTemplate); err != nil {
				return
			}
			uc = append(uc, c)
		}
		if err = rows.Err(); err != nil {
			return
		}

		return
	}
}

func (u *User) GetCorrectionsTemplate() (tpls []int64, err error) {
	if rows, errr := DBQuery("SELECT id_template FROM student_corrected WHERE id_user=?", u.Id); errr != nil {
		return nil, errr
	} else {
		defer rows.Close()

		for rows.Next() {
			var tpl int64
			if err = rows.Scan(&tpl); err != nil {
				return
			}
			tpls = append(tpls, tpl)
		}
		if err = rows.Err(); err != nil {
			return
		}

		return
	}
}

func (u *User) GetCorrection(id int) (c UserCorrection, err error) {
	err = DBQueryRow("SELECT id_correction, id_template FROM student_corrected WHERE id_user=? AND id_correction=?", u.Id, id).Scan(&c.Id, &c.IdTemplate)
	return
}

func (u *User) NewCorrection(id int64) (*UserCorrectionSummary, error) {
	if res, err := DBExec("INSERT INTO student_corrected (id_user, id_template) VALUES (?, ?)", u.Id, id); err != nil {
		return nil, err
	} else if cid, err := res.LastInsertId(); err != nil {
		return nil, err
	} else if ucs, err := u.ComputeScoreQuestion(id); err != nil {
		return nil, err
	} else {
		ucs.LastId = cid
		return ucs, nil
	}
}

func (c *UserCorrection) Delete(u User) (*UserCorrectionSummary, error) {
	if res, err := DBExec("DELETE FROM student_corrected WHERE id_correction = ?", c.Id); err != nil {
		return nil, err
	} else if _, err := res.RowsAffected(); err != nil {
		return nil, err
	} else if ucs, err := u.ComputeScoreQuestion(c.IdTemplate); err != nil {
		return nil, err
	} else {
		return ucs, nil
	}
}

type UserCorrectionSummary struct {
	LastId            int64  `json:"last_id,omitempty"`
	Score             int    `json:"score"`
	ScoreExplaination string `json:"score_explaination"`
}

func (u *User) ComputeScoreQuestion(idtpl int64) (*UserCorrectionSummary, error) {
	if tpl, err := GetCorrectionTemplate(idtpl); err != nil {
		return nil, err
	} else if question, err := getQuestion(int(tpl.IdQuestion)); err != nil {
		return nil, err
	} else {
		return question.ComputeScoreQuestion(u)
	}
}

func (q *Question) ComputeScoreQuestion(u *User) (*UserCorrectionSummary, error) {
	if templates, err := q.GetCorrectionTemplates(); err != nil {
		return nil, err
	} else if corrections, err := u.GetCorrectionsTemplate(); err != nil {
		return nil, err
	} else {
		tpls := map[int64]CorrectionTemplate{}
		for _, tpl := range templates {
			tpls[tpl.Id] = tpl
		}

		score := 100
		var expl []string

		for _, correction := range corrections {
			if _, ok := tpls[correction]; ok {
				score += tpls[correction].Score
				if tpls[correction].ScoreExplaination != "" {
					expl = append(expl, tpls[correction].ScoreExplaination)
				}
				delete(tpls, correction)
			}
		}

		return &UserCorrectionSummary{Score: score, ScoreExplaination: strings.Join(expl, ". ")}, nil
	}
}