package hammerhead

import (
	"crypto/tls"
	"errors"
	"fmt"
	"net"
	"net/http"
	"net/smtp"
	"strconv"
	"strings"
	"time"
)

func (s *Server) getSettings(w http.ResponseWriter, r *http.Request, p *principal) {
	s.mu.Lock()
	defer s.mu.Unlock()
	st := s.st.Settings
	st.SMTP.Pass = "" // write-only
	writeJSON(w, 200, map[string]any{"settings": st, "smtpPassSet": s.st.Settings.SMTP.Pass != ""})
}

func (s *Server) putSettings(w http.ResponseWriter, r *http.Request, p *principal) {
	var in Settings
	if !decode(w, r, &in) {
		return
	}
	in.DashboardURL = strings.TrimRight(strings.TrimSpace(in.DashboardURL), "/")
	if in.DashboardURL != "" && !strings.HasPrefix(in.DashboardURL, "http://") && !strings.HasPrefix(in.DashboardURL, "https://") {
		fail(w, 400, errors.New("dashboard URL must start with http:// or https://"))
		return
	}
	if m := in.SMTP.Mode; m != "" && m != "starttls" && m != "tls" && m != "none" {
		fail(w, 400, errors.New("smtp mode must be starttls, tls or none"))
		return
	}
	s.mu.Lock()
	if in.SMTP.Pass == "" {
		in.SMTP.Pass = s.st.Settings.SMTP.Pass // blank keeps the saved password
	}
	if s.opts.DashboardURL != "" {
		in.DashboardURL = s.st.Settings.DashboardURL // pinned by flag/env
	}
	in.SelfEdgeID = s.st.Settings.SelfEdgeID // not editable here; losing it would make the next start create a second self edge
	s.st.Settings = in
	s.bump() // edges receive the dashboard URL and ACME settings
	s.mu.Unlock()
	s.audit("", p.User.Email, "settings.update", "")
	ok(w)
}

func (s *Server) testMail(w http.ResponseWriter, r *http.Request, p *principal) {
	if err := s.Mailer(p.User.Email, "Hammerhead test email", "If you can read this, outgoing email works."); err != nil {
		fail(w, 400, err)
		return
	}
	ok(w)
}

func (s *Server) mailConfigured() bool {
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.st.Settings.SMTP.Host != ""
}

// smtpSend is the default Mailer.
func (s *Server) smtpSend(to, subject, body string) error {
	s.mu.Lock()
	c := s.st.Settings.SMTP
	s.mu.Unlock()
	if c.Host == "" {
		return errors.New("Email is not set up yet. Set it up under Server, Settings.")
	}
	if c.Port == 0 {
		c.Port = 587
		if c.Mode == "tls" {
			c.Port = 465
		}
	}
	if c.From == "" {
		c.From = c.User
	}
	addr := net.JoinHostPort(c.Host, strconv.Itoa(c.Port))
	msg := fmt.Sprintf("From: %s\r\nTo: %s\r\nSubject: %s\r\nMIME-Version: 1.0\r\nContent-Type: text/plain; charset=utf-8\r\n\r\n%s\r\n",
		c.From, to, strings.NewReplacer("\r", "", "\n", " ").Replace(subject), body)

	d := net.Dialer{Timeout: 10 * time.Second}
	conn, err := d.Dial("tcp", addr)
	if err != nil {
		return err
	}
	if c.Mode == "tls" {
		conn = tls.Client(conn, &tls.Config{ServerName: c.Host})
	}
	conn.SetDeadline(time.Now().Add(30 * time.Second))
	cl, err := smtp.NewClient(conn, c.Host)
	if err != nil {
		conn.Close()
		return err
	}
	defer cl.Close()
	if c.Mode == "" || c.Mode == "starttls" {
		if ok, _ := cl.Extension("STARTTLS"); ok {
			if err := cl.StartTLS(&tls.Config{ServerName: c.Host}); err != nil {
				return err
			}
		}
	}
	if c.User != "" {
		if err := cl.Auth(smtp.PlainAuth("", c.User, c.Pass, c.Host)); err != nil {
			return err
		}
	}
	if err := cl.Mail(c.From); err != nil {
		return err
	}
	if err := cl.Rcpt(to); err != nil {
		return err
	}
	wc, err := cl.Data()
	if err != nil {
		return err
	}
	if _, err := wc.Write([]byte(msg)); err != nil {
		return err
	}
	if err := wc.Close(); err != nil {
		return err
	}
	return cl.Quit()
}