package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"

	"fn-registry/functions/infra"
)

const syncLayerVersion = "v0.1.0"

func main() {
	flags := flag.NewFlagSet("kanban_cpp_backend", flag.ExitOnError)
	port := flags.Int("port", 8403, "HTTP port")
	dbPath := flags.String("db", "operations.db", "SQLite database path")
	flagsPath := flags.String("flags", "dev/feature_flags.json", "Feature flags JSON path (missing file → all disabled)")
	flags.Parse(os.Args[1:])

	featureFlags, err := loadFeatureFlags(*flagsPath)
	if err != nil {
		log.Fatalf("load feature flags: %v", err)
	}
	for name, fl := range featureFlags.Flags {
		log.Printf("feature flag %q enabled=%v", name, fl.Enabled)
	}

	db, err := openDB(*dbPath)
	if err != nil {
		log.Fatalf("open db: %v", err)
	}
	defer db.Close()

	// SSE: hub + fsnotify watcher for dev/issues + dev/flows.
	globalHub = NewHub()
	startBoardsWatcher(globalHub)

	mux := infra.HTTPRouter(apiRoutes(db, &featureFlags))
	mux.HandleFunc("/health", handleHealth(*port))

	chain := infra.HTTPMiddlewareChain(
		infra.HTTPLoggerMiddleware(os.Stdout),
		infra.HTTPCORSMiddleware([]string{"*"}, []string{"GET", "POST", "PATCH", "DELETE", "OPTIONS"}),
	)
	handler := chain(mux)

	addr := fmt.Sprintf(":%d", *port)
	log.Printf("kanban_cpp_backend starting on http://0.0.0.0%s (sync layer %s)", addr, syncLayerVersion)
	log.Printf("database: %s", *dbPath)

	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer cancel()

	if err := infra.HTTPServe(addr, handler, ctx); err != nil {
		log.Fatalf("server: %v", err)
	}
}

// handleHealth returns 200 with a small JSON describing the service. No auth.
func handleHealth(port int) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(map[string]any{
			"status":     "ok",
			"port":       port,
			"sync_layer": syncLayerVersion,
		})
	}
}