package hammerhead

import (
	"context"
	"errors"
	"net/http"
	"strings"
	"sync"
	"time"

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

func (s *Server) updateConfig(app, current string) selfupdate.Config {
	o := s.opts
	server := o.UpdateServer
	if server == "" {
		server = "https://git.veillax.com"
	}
	owner := "Veillax"
	if o.UpdateRepo != "" {
		owner = strings.SplitN(o.UpdateRepo, "/", 2)[0]
	}
	return selfupdate.Config{Server: server, Repo: owner + "/" + app, App: app, Current: current}
}

// checkUpdate asks the release server whether a newer Hammerhead exists. It only looks.
func (s *Server) checkUpdate(w http.ResponseWriter, r *http.Request, p *principal) {
	o := s.opts
	ctx, cancel := context.WithTimeout(r.Context(), 20*time.Second)
	defer cancel()
	out := map[string]any{"current": o.Version, "autoUpdate": o.AutoUpdate, "checked": time.Now()}
	latest, newer, err := selfupdate.Check(ctx, s.updateConfig("hammerhead", o.Version))
	out["latest"], out["newer"] = latest, newer
	if err != nil {
		out["error"] = err.Error()
	}
	writeJSON(w, 200, out)
}

// applyUpdate installs the newest release of Hammerhead itself and restarts into it. Like the
// scheduled check it needs auto-update to be on, which is also what makes the binary replaceable.
func (s *Server) applyUpdate(w http.ResponseWriter, r *http.Request, p *principal) {
	if !s.opts.AutoUpdate {
		fail(w, 400, errors.New("auto-update is off: set HAMMERHEAD_AUTO_UPDATE=1 and restart Hammerhead, or update it by hand"))
		return
	}
	cfg := s.updateConfig("hammerhead", s.opts.Version)
	cfg.Restart = func(exe string) error { s.Close(); return selfupdate.Restart(exe) }
	s.audit("", p.User.Email, "server.update", "")
	go func() {
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
		defer cancel()
		selfupdate.CheckOnce(ctx, cfg) // on success the process is replaced and this never returns
	}()
	writeJSON(w, 200, map[string]any{"started": true})
}

// latestVersions returns the newest release of each program, for "update available" badges. Results
// are cached for ten minutes so a busy dashboard doesn't hammer the release server.
func (s *Server) latestVersions(w http.ResponseWriter, r *http.Request, p *principal) {
	s.verMu.Lock()
	if time.Since(s.verAt) > 10*time.Minute || s.verCache == nil {
		ctx, cancel := context.WithTimeout(r.Context(), 15*time.Second)
		out := map[string]string{}
		var mu sync.Mutex
		var wg sync.WaitGroup
		for _, app := range []string{"hammerhead", "blacktip", "bamboo"} {
			wg.Add(1)
			go func(app string) {
				defer wg.Done()
				if tag, _, err := selfupdate.Check(ctx, s.updateConfig(app, "")); err == nil && tag != "" {
					mu.Lock()
					out[app] = tag
					mu.Unlock()
				}
			}(app)
		}
		wg.Wait()
		cancel()
		s.verCache, s.verAt = out, time.Now()
	}
	out := s.verCache
	s.verMu.Unlock()
	writeJSON(w, 200, out)
}

// noteUpdateReport records what an edge or site says about its version and any update that was
// requested of it. It reports whether a pending request was answered, which means the config the
// agent polls has changed (it no longer carries the request).
func noteUpdateReport(version *string, auto *bool, updateID, updateMsg *string, inVersion string, inAuto bool, inID, inMsg string) bool {
	upgraded := *version != "" && inVersion != "" && inVersion != *version
	if inVersion != "" {
		*version = inVersion
	}
	*auto = inAuto
	if *updateID == "" {
		return false
	}
	switch {
	case inID == *updateID && inMsg != "":
		*updateMsg = inMsg
	case upgraded:
		*updateMsg = "updated to " + inVersion
	default:
		return false
	}
	*updateID = ""
	return true
}

func (s *Server) updateEdge(w http.ResponseWriter, r *http.Request, p *principal) {
	s.mu.Lock()
	defer s.mu.Unlock()
	e := s.findEdge(r.PathValue("id"))
	if e == nil {
		fail(w, 404, errors.New("no such edge"))
		return
	}
	if err := requestUpdate(&e.AutoUpdate, &e.UpdateID, &e.UpdateMsg, s.edgeOnline(e), "BLACKTIP"); err != nil {
		fail(w, 400, err)
		return
	}
	s.bump()
	s.audit("", p.User.Email, "edge.update", e.Name)
	ok(w)
}

func (s *Server) updateSite(w http.ResponseWriter, r *http.Request, c *orgCtx) {
	s.mu.Lock()
	defer s.mu.Unlock()
	st := s.findSite(r.PathValue("id"))
	if st == nil || !s.siteVisible(c, st) {
		fail(w, 404, errors.New("no such site"))
		return
	}
	if st.Local {
		fail(w, 400, errors.New("this site is the edge's own machine; update the edge instead"))
		return
	}
	if err := requestUpdate(&st.AutoUpdate, &st.UpdateID, &st.UpdateMsg, s.siteOnline(st), "BAMBOO"); err != nil {
		fail(w, 400, err)
		return
	}
	s.bump()
	s.audit(c.Org.ID, c.Actor, "site.update", st.Name)
	ok(w)
}

// requestUpdate marks an update as wanted. The agent installs it only if it has auto-update on, and
// the request stays until the agent answers (or reports a new version). Asking again replaces it.
func requestUpdate(auto *bool, updateID, updateMsg *string, online bool, prefix string) error {
	if !online {
		return errors.New("it is offline right now")
	}
	if !*auto {
		return errors.New("it isn't running with auto-update on, so it won't install updates from here (set " + prefix + "_AUTO_UPDATE=1 and restart it)")
	}
	*updateID, *updateMsg = randHex(8), ""
	return nil
}