package bootstrap

import (
	"context"
	"encoding/json"
	"html"
	"log"
	"net"
	"net/http"
	"strings"
	"time"

	"gitea.dooplex.hu/admin/felhom-controller/internal/config"
	"gitea.dooplex.hu/admin/felhom-controller/internal/i18n"
)

// ── Not configured yet: wait for the hub (R-554, v0.308.0, `09` §3 decision 222) ───────────────
//
// Until v0.308.0 a box whose first boot could not ingest its configuration (no or bad bootstrap.json, a
// hub it could not reach, a failed write) entered the first-boot SETUP WIZARD — eight pages built for the
// retired docker-setup.sh install. The agent provisions every box now; the wizard is deleted. Such a box
// shows ONE page instead — „Felhom has not reached the central service yet", in both languages — and
// retries the ingestion every minute. When it succeeds the page goes away and the controller starts
// normally on the same listener. Pinned by TestWaitForConfig_ServesWaitingPageThenStarts.

// WaitRetryInterval is how often an unconfigured box retries the ingestion.
const WaitRetryInterval = time.Minute

// Unconfigured reports whether this controller has no customer id — the only state that waits.
func Unconfigured(cfg *config.Config) bool {
	return cfg == nil || cfg.Customer.ID == ""
}

// WaitingHandler serves the waiting page on every path, and a health answer on /api/health (the
// container's health check must keep passing while the box waits — it is not broken, it is early).
func WaitingHandler(version string) http.Handler {
	page := waitingPage()
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/api/health" {
			w.Header().Set("Content-Type", "application/json")
			_ = json.NewEncoder(w).Encode(map[string]interface{}{
				"ok": true, "message": "felhom-controller is waiting for its configuration",
				"waiting_for_hub": true, "setup_mode": true, "version": version,
			})
			return
		}
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		w.Header().Set("Cache-Control", "no-store")
		_, _ = w.Write([]byte(page))
	})
}

// waitingPage is the page in BOTH languages: an unconfigured box has no household setting to choose by.
func waitingPage() string {
	var b strings.Builder
	b.WriteString("<!DOCTYPE html>\n<html lang=\"hu\">\n<head>\n<meta charset=\"UTF-8\">\n")
	b.WriteString("<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\n")
	b.WriteString("<meta http-equiv=\"refresh\" content=\"60\">\n<title>Felhom</title>\n")
	b.WriteString("<style>body{font-family:system-ui,sans-serif;max-width:40rem;margin:3rem auto;padding:0 1rem;line-height:1.5}section{margin-bottom:2rem}</style>\n")
	b.WriteString("</head>\n<body>\n")
	bundle, err := i18n.Shared()
	for _, lang := range i18n.Supported {
		title, body := "Felhom", ""
		if err == nil {
			title, body = bundle.Msg(lang, "waiting.title"), bundle.Msg(lang, "waiting.body")
		}
		b.WriteString("<section lang=\"" + lang + "\">\n<h1>" + html.EscapeString(title) + "</h1>\n<p>" + html.EscapeString(body) + "</p>\n</section>\n")
	}
	b.WriteString("</body>\n</html>\n")
	return b.String()
}

// WaitForConfig serves the waiting page on ln and retries MaybeIngest every `every` until the box is
// configured, then closes the page and returns the configured config. It returns nil when ctx ends first
// (the process is stopping). ln may be nil (the port could not be bound): the retries still run.
func WaitForConfig(ctx context.Context, ln net.Listener, configPath string, cfg *config.Config, logger *log.Logger, pull PullFunc, every time.Duration, version string) *config.Config {
	var srv *http.Server
	if ln != nil {
		srv = &http.Server{Handler: WaitingHandler(version), ReadTimeout: 30 * time.Second, WriteTimeout: 30 * time.Second}
		go func() {
			if err := srv.Serve(ln); err != nil && err != http.ErrServerClosed {
				logger.Printf("[ERROR] bootstrap: waiting page server: %v", err)
			}
		}()
		logger.Printf("[INFO] bootstrap: not configured yet — serving the waiting page on %s, retrying every %s", ln.Addr(), every)
	}
	stop := func() {
		if srv == nil {
			return
		}
		sctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		_ = srv.Shutdown(sctx)
	}
	t := time.NewTicker(every)
	defer t.Stop()
	for attempt := 1; ; attempt++ {
		select {
		case <-ctx.Done():
			stop()
			return nil
		case <-t.C:
		}
		next := MaybeIngest(configPath, cfg, logger, pull)
		if !Unconfigured(next) {
			logger.Printf("[INFO] bootstrap: configured after %d retries — closing the waiting page and starting", attempt)
			stop()
			return next
		}
		cfg = next
	}
}