package main

import (
	"bytes"
	"fmt"
	"github.com/Masterminds/sprig"
	"gopkg.in/gomail.v2"
	"text/template"
)

type NotificationMail interface {
	GetData() interface{}
	GetTemplate() string
	GetSubject() string
	GetHeaders() map[string]string
}

type VoterMail interface {
	GetData() interface{}
	GetTemplate() string
	GetSubject() string
	GetRecipient() (string, string)
}

var notifyMail = make(chan NotificationMail, 1)
var voterMail = make(chan VoterMail, 1)
var quitMailNotifier = make(chan int)

func CloseMailNotifier() {
	quitMailNotifier <- 1
}

func MailNotifier() {
	logger.Println("Launched mail notifier")
	for {
		select {
		case notification := <-notifyMail:
			mailText, err := buildMail(notification.GetTemplate(), notification.GetData())
			if err != nil {
				logger.Println("ERROR building mail:", err)
				continue
			}

			m := gomail.NewMessage()
			m.SetHeader("From", config.NoticeSenderAddress)
			m.SetHeader("To", config.BoardMailAddress)
			m.SetHeader("Subject", notification.GetSubject())
			for header, value := range notification.GetHeaders() {
				m.SetHeader(header, value)
			}
			m.SetBody("text/plain", mailText.String())

			d := gomail.NewDialer(config.MailServer.Host, config.MailServer.Port, "", "")
			if err := d.DialAndSend(m); err != nil {
				logger.Println("ERROR sending mail:", err)
			}
		case notification := <-voterMail:
			mailText, err := buildMail(notification.GetTemplate(), notification.GetData())
			if err != nil {
				logger.Println("ERROR building mail:", err)
				continue
			}

			m := gomail.NewMessage()
			m.SetHeader("From", config.ReminderSenderAddress)
			address, name := notification.GetRecipient()
			m.SetAddressHeader("To", address, name)
			m.SetHeader("Subject", notification.GetSubject())
			m.SetBody("text/plain", mailText.String())

			d := gomail.NewDialer(config.MailServer.Host, config.MailServer.Port, "", "")
			if err := d.DialAndSend(m); err != nil {
				logger.Println("ERROR sending mail:", err)
			}
		case <-quitMailNotifier:
			fmt.Println("Ending mail notifier")
			return
		}
	}
}

func buildMail(templateName string, context interface{}) (mailText *bytes.Buffer, err error) {
	t, err := template.New(templateName).Funcs(
		sprig.GenericFuncMap()).ParseFiles(fmt.Sprintf("templates/%s", templateName))
	if err != nil {
		return
	}

	mailText = bytes.NewBufferString("")
	t.Execute(mailText, context)

	return
}

type NotificationClosedDecision struct {
	decision Decision
	voteSums VoteSums
}

func (n *NotificationClosedDecision) GetData() interface{} {
	return struct {
		*Decision
		*VoteSums
	}{&n.decision, &n.voteSums}
}

func (n *NotificationClosedDecision) GetTemplate() string { return "closed_motion_mail.txt" }

func (n *NotificationClosedDecision) GetSubject() string {
	return fmt.Sprintf("Re: %s - %s - finalised", n.decision.Tag, n.decision.Title)
}

func (n *NotificationClosedDecision) GetHeaders() map[string]string {
	return map[string]string{"References": fmt.Sprintf("<%s>", n.decision.Tag)}
}

type NotificationCreateMotion struct {
	decision Decision
	voter    Voter
}

func (n *NotificationCreateMotion) GetData() interface{} {
	voteURL := fmt.Sprintf("%s/vote", config.BaseURL)
	unvotedURL := fmt.Sprintf("%s/motions/?unvoted=1", config.BaseURL)
	return struct {
		*Decision
		Name       string
		VoteURL    string
		UnvotedURL string
	}{&n.decision, n.voter.Name, voteURL, unvotedURL}
}

func (n *NotificationCreateMotion) GetTemplate() string { return "create_motion_mail.txt" }

func (n *NotificationCreateMotion) GetSubject() string {
	return fmt.Sprintf("%s - %s", n.decision.Tag, n.decision.Title)
}

func (n *NotificationCreateMotion) GetHeaders() map[string]string {
	return map[string]string{"Message-ID": fmt.Sprintf("<%s>", n.decision.Tag)}
}

type NotificationUpdateMotion struct {
	decision Decision
	voter    Voter
}

func (n *NotificationUpdateMotion) GetData() interface{} {
	voteURL := fmt.Sprintf("%s/vote", config.BaseURL)
	unvotedURL := fmt.Sprintf("%s/motions/?unvoted=1", config.BaseURL)
	return struct {
		*Decision
		Name       string
		VoteURL    string
		UnvotedURL string
	}{&n.decision, n.voter.Name, voteURL, unvotedURL}
}

func (n *NotificationUpdateMotion) GetTemplate() string { return "update_motion_mail.txt" }

func (n *NotificationUpdateMotion) GetSubject() string {
	return fmt.Sprintf("Re: %s - %s", n.decision.Tag, n.decision.Title)
}

func (n *NotificationUpdateMotion) GetHeaders() map[string]string {
	return map[string]string{"References": fmt.Sprintf("<%s>", n.decision.Tag)}
}

type NotificationWithDrawMotion struct {
	decision Decision
	voter    Voter
}

func (n *NotificationWithDrawMotion) GetData() interface{} {
	return struct {
		*Decision
		Name string
	}{&n.decision, n.voter.Name}
}

func (n *NotificationWithDrawMotion) GetTemplate() string { return "withdraw_motion_mail.txt" }

func (n *NotificationWithDrawMotion) GetSubject() string {
	return fmt.Sprintf("Re: %s - %s - withdrawn", n.decision.Tag, n.decision.Title)
}

func (n *NotificationWithDrawMotion) GetHeaders() map[string]string {
	return map[string]string{"References": fmt.Sprintf("<%s>", n.decision.Tag)}
}

type RemindVoterNotification struct {
	voter     Voter
	decisions []Decision
}

func (n *RemindVoterNotification) GetData() interface{} {
	return struct {
		Decisions []Decision
		Name      string
		BaseURL   string
	}{n.decisions, n.voter.Name, config.BaseURL}
}

func (n *RemindVoterNotification) GetTemplate() string { return "remind_voter_mail.txt" }

func (n *RemindVoterNotification) GetSubject() string { return "Outstanding CAcert board votes" }

func (n *RemindVoterNotification) GetRecipient() (address string, name string) {
	address, name = n.voter.Reminder, n.voter.Name
	return
}