package main

import (
	"encoding/json"
	"log"
	"net/http"
	"net/url"
)

type ReportElement struct {
	Label string
	Value int64
}

type Report struct {
	ReportId string
	Title    string
	Data     []*ReportElement
}

func (r *ReportElement) Write(w http.ResponseWriter) error {
	enc := json.NewEncoder(w)
	return enc.Encode(r)
}

func (r *Report) Write(w http.ResponseWriter) error {
	enc := json.NewEncoder(w)
	return enc.Encode(r)
}

func (r *Report) FromSummedAttendeeList(attendees *[]*Attendee) {
	attendeeMap := make(map[string]int64)
	r.Data = make([]*ReportElement, 0)

	for i := range *attendees {
		attendeeMap[(*attendees)[i].Name] += 1
	}
	for name, count := range attendeeMap {
		var element ReportElement
		element.Label = name
		element.Value = count
		r.Data = append(r.Data, &element)
	}
}

func (r *Report) FromSummedSuggestionList(suggestions *[]*Suggestion) {
	suggestionMap := make(map[string]int64)
	r.Data = make([]*ReportElement, 0)

	for i := range *suggestions {
		suggestionMap[(*suggestions)[i].RestaurantName] += 1
	}
	for name, count := range suggestionMap {
		var element ReportElement
		element.Label = name
		element.Value = count
		r.Data = append(r.Data, &element)
	}
}

func GetAllSuggestions(userid int64) (*[]*Suggestion, error) {
	var suggestions []*Suggestion

	_, err := DB.Select(&suggestions, "SELECT * from suggestions WHERE UserId=?", userid)
	if err != nil {
		return nil, err
	}

	return &suggestions, nil
}

func GetVetoedSuggestions(userid int64) (*[]*Suggestion, error) {
	var suggestions []*Suggestion

	_, err := DB.Select(&suggestions, "SELECT suggestions.* FROM suggestions INNER JOIN suggestions AS s2 WHERE suggestions.UserId=? AND s2.UserId=? AND suggestions.Date=s2.Date AND s2.VetoingId=suggestions.SuggestionId", userid, userid)
	if err != nil {
		return nil, err
	}

	return &suggestions, nil
}

func GetNonVetoedSuggestions(userid int64) (*[]*Suggestion, error) {
	var suggestions []*Suggestion

	_, err := DB.Select(&suggestions, "SELECT suggestions.* FROM suggestions LEFT OUTER JOIN suggestions AS s2 ON suggestions.SuggestionId=s2.VetoingId WHERE s2.SuggestionId IS NULL AND suggestions.UserId=?;", userid)
	if err != nil {
		return nil, err
	}

	return &suggestions, nil
}

func GetAllAttendees(userid int64) (*[]*Attendee, error) {
	var attendees []*Attendee

	_, err := DB.Select(&attendees, "SELECT * from attendees WHERE UserId=?", userid)
	if err != nil {
		return nil, err
	}

	return &attendees, nil
}

func ReportHandler(w http.ResponseWriter, r *http.Request) {
	user, err := GetUserFromSession(r)
	if err != nil {
		WriteError(w, 1 /*Not Signed In*/)
		return
	}

	if r.Method == "GET" {
		var report Report

		query, _ := url.ParseQuery(r.URL.RawQuery)
		reportid := query.Get("id")
		report.ReportId = reportid

		if reportid == "non-vetoed-suggestions" {
			report.Title = "Non-Vetoed Suggestions"
			suggestions, err := GetNonVetoedSuggestions(user.UserId)
			if err != nil {
				WriteError(w, 999 /*Internal Error*/)
				log.Print(err)
				return
			}
			report.FromSummedSuggestionList(suggestions)
		} else if reportid == "vetoed-suggestions" {
			report.Title = "Vetoed Suggestions"
			suggestions, err := GetVetoedSuggestions(user.UserId)
			if err != nil {
				WriteError(w, 999 /*Internal Error*/)
				log.Print(err)
				return
			}
			report.FromSummedSuggestionList(suggestions)
		} else if reportid == "suggestions" {
			report.Title = "Suggestion Frequency"
			suggestions, err := GetAllSuggestions(user.UserId)
			if err != nil {
				WriteError(w, 999 /*Internal Error*/)
				log.Print(err)
				return
			}
			report.FromSummedSuggestionList(suggestions)
		} else if reportid == "attendees" {
			report.Title = "Attendee Frequency"
			attendees, err := GetAllAttendees(user.UserId)
			if err != nil {
				WriteError(w, 999 /*Internal Error*/)
				log.Print(err)
				return
			}
			report.FromSummedAttendeeList(attendees)
		} else {
			WriteError(w, 3 /*Invalid Request*/)
			return
		}

		err = (&report).Write(w)
		if err != nil {
			WriteError(w, 999 /*Internal Error*/)
			log.Print(err)
			return
		}
	} else {
		/* No POST, PUT, or DELETE */
		WriteError(w, 3 /*Invalid Request*/)
		return
	}
}