package hammerhead

import (
	"errors"
	"net"
	"net/http"
	"strings"

	"git.veillax.com/Veillax/reef/model"
)

const defaultMailListen = "127.0.0.1:2525"

func (s *Server) findMailEgress(id string) *model.MailEgress {
	for _, e := range s.st.MailEgress {
		if e.ID == id {
			return e
		}
	}
	return nil
}

func isLoopbackListen(addr string) bool {
	host, _, err := net.SplitHostPort(addr)
	if err != nil {
		return false
	}
	if strings.EqualFold(host, "localhost") {
		return true
	}
	ip := net.ParseIP(host)
	return ip != nil && ip.IsLoopback()
}

// validateMailEgress checks e against org c and normalises it. Caller holds s.mu.
func (s *Server) validateMailEgress(c *orgCtx, e *model.MailEgress) error {
	e.OrgID = c.Org.ID
	e.Name = strings.TrimSpace(e.Name)
	site := s.findSite(e.SiteID)
	if site == nil || site.Local || site.OrgID != c.Org.ID {
		return errors.New("choose one of your sites: the mail server's network (the built-in local site already sends from the edge itself)")
	}
	edge := s.findEdge(e.EdgeID)
	if edge == nil || !s.edgeAllowedFor(edge, c.Org.ID) {
		return errors.New("choose an edge")
	}
	e.Listen = strings.TrimSpace(e.Listen)
	if e.Listen == "" {
		e.Listen = defaultMailListen
	}
	if !validAddr(e.Listen) {
		return errors.New("listen address must look like 127.0.0.1:2525 (an address on the site's machine)")
	}
	for _, o := range s.st.MailEgress {
		if o.ID != e.ID && o.SiteID == e.SiteID && o.Listen == e.Listen {
			return errors.New("another mail egress on that site already listens on " + e.Listen)
		}
	}
	ip := net.ParseIP(strings.TrimSpace(e.SourceIP))
	if ip == nil || ip.IsUnspecified() {
		return errors.New("choose the edge IP address your mail should leave from")
	}
	e.SourceIP = ip.String()
	e.HeloName = strings.ToLower(strings.TrimSpace(e.HeloName))
	if !validHostname(e.HeloName) || strings.HasPrefix(e.HeloName, "*.") {
		return errors.New("enter the hostname your mail server announces, like mail.example.com (its reverse DNS should match)")
	}
	e.Smarthost = strings.TrimSpace(e.Smarthost)
	if e.Smarthost != "" && !validAddr(e.Smarthost) {
		return errors.New("smarthost must look like smtp.example.com:587")
	}
	if e.RatePerMinute < 0 || e.RatePerMinute > 6000 {
		return errors.New("messages per minute must be between 1 and 6000")
	}
	if e.Username != "" && e.Password == "" {
		return errors.New("set a password too, or clear the username")
	}
	if e.Username == "" && !isLoopbackListen(e.Listen) {
		return errors.New("listening beyond this machine without a password would let anything on your network send mail from your IP; set a username and password, or listen on 127.0.0.1")
	}
	if e.Name == "" {
		e.Name = "mail via " + e.HeloName
	}
	return nil
}

func (s *Server) saveMailEgress(w http.ResponseWriter, r *http.Request, c *orgCtx) {
	var in model.MailEgress
	if !decode(w, r, &in) {
		return
	}
	s.mu.Lock()
	defer s.mu.Unlock()
	id := r.PathValue("id")
	idx := -1
	if id != "" {
		for i, e := range s.st.MailEgress {
			if e.ID == id && e.OrgID == c.Org.ID {
				idx = i
			}
		}
		if idx < 0 {
			fail(w, 404, errors.New("no such mail egress"))
			return
		}
		in.ID = id
		if in.Password == "" && in.Username != "" && in.Username == s.st.MailEgress[idx].Username {
			in.Password = s.st.MailEgress[idx].Password // blank keeps the saved password
		}
	}
	if err := s.validateMailEgress(c, &in); err != nil {
		fail(w, 400, err)
		return
	}
	if idx >= 0 {
		s.st.MailEgress[idx] = &in
		delete(s.mailStatus, id)
	} else {
		in.ID = newID()
		s.st.MailEgress = append(s.st.MailEgress, &in)
	}
	s.bump()
	s.audit(c.Org.ID, c.Actor, "mailegress.save", in.Name)
	resp := in // the stored record keeps its password; the response never carries it
	resp.Password = ""
	writeJSON(w, 200, resp)
}

func (s *Server) deleteMailEgress(w http.ResponseWriter, r *http.Request, c *orgCtx) {
	id := r.PathValue("id")
	s.mu.Lock()
	defer s.mu.Unlock()
	e := s.findMailEgress(id)
	if e == nil || e.OrgID != c.Org.ID {
		fail(w, 404, errors.New("no such mail egress"))
		return
	}
	s.st.MailEgress = filter(s.st.MailEgress, func(x *model.MailEgress) bool { return x.ID != id })
	delete(s.mailStatus, id)
	delete(s.mailChecks, id)
	s.bump()
	s.audit(c.Org.ID, c.Actor, "mailegress.delete", e.Name)
	ok(w)
}

type mailEgressView struct {
	model.MailEgress
	PasswordSet bool             `json:"passwordSet"`
	Status      string           `json:"status"`
	StatusKnown bool             `json:"statusKnown"`
	Check       *model.MailCheck `json:"check,omitempty"`
}

// mailEgressViewsLocked lists an org's mail egress without secrets. Caller holds s.mu.
func (s *Server) mailEgressViewsLocked(orgID string) []mailEgressView {
	out := []mailEgressView{}
	for _, e := range s.st.MailEgress {
		if e.OrgID != orgID {
			continue
		}
		v := mailEgressView{MailEgress: *e, PasswordSet: e.Password != ""}
		v.Password = ""
		v.Status, v.StatusKnown = s.mailStatus[e.ID]
		if chk, ok := s.mailChecks[e.ID]; ok {
			c := chk
			v.Check = &c
		}
		out = append(out, v)
	}
	return out
}