package hammerhead

import (
	"errors"
	"fmt"
	"net"
	"os"
	"path/filepath"
	"strconv"
	"strings"

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

const selfMappingID = "hammerhead-dashboard"

// ensureSelfEdge makes sure this server has an edge of its own, for a Blacktip on the same
// machine, and writes that edge's token to <data>/self-edge.env for the installer. The edge
// also carries a built-in https route for the dashboard (see selfMapping), so no separate
// reverse proxy is needed in front of Hammerhead.
func (s *Server) ensureSelfEdge() error {
	o := s.opts
	if o.SelfDomain == "" {
		return nil
	}
	host, port, err := net.SplitHostPort(o.SelfTarget)
	if err != nil {
		return fmt.Errorf("HAMMERHEAD_SELF_DOMAIN needs a listen address like 127.0.0.1:8080: %w", err)
	}
	if n, _ := strconv.Atoi(port); n < 1 || host == "" {
		return errors.New("the dashboard's listen address needs a host and a port")
	}
	s.mu.Lock()
	defer s.mu.Unlock()
	e := s.findEdge(s.st.Settings.SelfEdgeID)
	if e == nil {
		e = &model.Edge{ID: newID(), Name: "Hammerhead server", Token: randHex(24), AuthKey: randHex(32),
			TunnelAddr: o.SelfTunnel, TunnelIP: s.allocIPLocked(), OrgIDs: []string{}, IPs: []string{}}
		s.st.Edges = append(s.st.Edges, e)
		s.st.Sites = append(s.st.Sites, &model.Site{ID: newID(), Name: e.Name + " (this machine)",
			Local: true, EdgeID: e.ID, Connected: []string{}})
		s.st.Settings.SelfEdgeID = e.ID
		s.bump()
	}
	body := "# written by Hammerhead for the Blacktip on this machine; keep it private\nBLACKTIP_TOKEN=" + e.Token + "\n"
	return os.WriteFile(filepath.Join(s.dir, "self-edge.env"), []byte(body), 0o600)
}

// selfMapping is the dashboard's own route on the self edge: https on the configured name,
// forwarded to Hammerhead's listen address through the edge's local site. It is added to that
// edge's config and never stored, so it can't be edited or deleted by mistake in the UI.
// Caller holds s.mu.
func (s *Server) selfMapping(e *model.Edge) *model.Mapping {
	o := s.opts
	if o.SelfDomain == "" || e.ID != s.st.Settings.SelfEdgeID {
		return nil
	}
	host, port, err := net.SplitHostPort(o.SelfTarget)
	if err != nil {
		return nil
	}
	n, _ := strconv.Atoi(port)
	for _, st := range s.st.Sites {
		if st.Local && st.EdgeID == e.ID {
			return &model.Mapping{ID: selfMappingID, Name: "Hammerhead dashboard", Proto: model.ProtoHTTPS, EdgeID: e.ID,
				BindIP: "0.0.0.0", Port: 443, Hostname: strings.ToLower(o.SelfDomain), Enabled: true, RedirectHTTP: true,
				HealthSeconds: -1, Targets: []model.Target{{SiteID: st.ID, Host: host, Port: n}}}
		}
	}
	return nil
}