// Command nebbet is the CLI for the nebbet.no static site generator.
//
// Usage:
//
//	nebbet build              – build all pages once
//	nebbet watch              – watch for changes and rebuild
//	nebbet serve [--port N]   – serve with live admin UI + watch mode
//	nebbet user add <name>    – add a user to the passwords file
//	nebbet user list          – list users
//	nebbet user delete <name> – remove a user
//	nebbet user passwd <name> – change a user's password
package main

import (
	"flag"
	"fmt"
	"net/http"
	"os"

	"nebbet.no/internal/admin"
	"nebbet.no/internal/auth"
	"nebbet.no/internal/builder"
	"nebbet.no/internal/db"
)

const (
	contentDir   = "content"
	outputDir    = "public"
	postsDir     = "content/posts"
	dataDir      = "data"
	metaDBPath   = "data/meta.db"
	searchDBPath = "data/search.db"
	passwordFile = ".passwords"
)

func main() {
	if len(os.Args) < 2 {
		usage()
		os.Exit(1)
	}
	switch os.Args[1] {
	case "build":
		cmdBuild(os.Args[2:])
	case "watch":
		cmdWatch()
	case "serve":
		cmdServe(os.Args[2:])
	case "user":
		cmdUser(os.Args[2:])
	default:
		fmt.Fprintf(os.Stderr, "unknown command %q\n", os.Args[1])
		usage()
		os.Exit(1)
	}
}

// ── build ─────────────────────────────────────────────────────────────────────

func cmdBuild(args []string) {
	fs := flag.NewFlagSet("build", flag.ExitOnError)
	watch := fs.Bool("watch", false, "watch for changes and rebuild")
	_ = fs.Parse(args)

	b := mustBuilder()
	defer b.MetaDB.Close()
	defer b.SearchDB.Close()

	if err := b.BuildAll(); err != nil {
		fmt.Fprintln(os.Stderr, "build error:", err)
		os.Exit(1)
	}
	if *watch {
		if err := b.Watch(); err != nil {
			fmt.Fprintln(os.Stderr, "watch error:", err)
			os.Exit(1)
		}
	}
}

// ── watch ─────────────────────────────────────────────────────────────────────

func cmdWatch() {
	b := mustBuilder()
	defer b.MetaDB.Close()
	defer b.SearchDB.Close()
	if err := b.BuildAll(); err != nil {
		fmt.Fprintln(os.Stderr, "build error:", err)
		os.Exit(1)
	}
	if err := b.Watch(); err != nil {
		fmt.Fprintln(os.Stderr, "watch error:", err)
		os.Exit(1)
	}
}

// ── serve ─────────────────────────────────────────────────────────────────────

func cmdServe(args []string) {
	fs := flag.NewFlagSet("serve", flag.ExitOnError)
	port := fs.String("port", "8080", "port to listen on")
	_ = fs.Parse(args)

	b := mustBuilder()
	defer b.MetaDB.Close()
	defer b.SearchDB.Close()

	// Initial build.
	if err := b.BuildAll(); err != nil {
		fmt.Fprintln(os.Stderr, "build error:", err)
		os.Exit(1)
	}

	// Watch in background.
	go func() {
		if err := b.Watch(); err != nil {
			fmt.Fprintln(os.Stderr, "watch error:", err)
		}
	}()

	adminSrv := &admin.Server{
		PostsDir: postsDir,
		AuthFile: passwordFile,
		Builder:  b,
	}

	mux := http.NewServeMux()
	// Admin routes — handled dynamically, never from the static output dir.
	mux.Handle("/admin/", http.StripPrefix("/admin", adminSrv))
	// Everything else — serve the pre-built static files.
	mux.Handle("/", http.FileServer(http.Dir(outputDir)))

	addr := ":" + *port
	fmt.Printf("listening on http://localhost%s\n", addr)
	fmt.Printf("  public site: http://localhost%s/\n", addr)
	fmt.Printf("  admin UI:    http://localhost%s/admin/\n", addr)
	if err := http.ListenAndServe(addr, mux); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

// ── user ─────────────────────────────────────────────────────────────────────

func cmdUser(args []string) {
	if len(args) == 0 {
		fmt.Fprintln(os.Stderr, "usage: nebbet user <add|list|delete|passwd> [username]")
		os.Exit(1)
	}
	a := auth.New(passwordFile)
	switch args[0] {
	case "add":
		requireArg(args, 1, "nebbet user add <username>")
		if err := a.AddUser(args[1]); err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		fmt.Println("user added:", args[1])
	case "list":
		users, err := a.ListUsers()
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		if len(users) == 0 {
			fmt.Println("(no users)")
			return
		}
		for _, u := range users {
			fmt.Println(u)
		}
	case "delete":
		requireArg(args, 1, "nebbet user delete <username>")
		if err := a.DeleteUser(args[1]); err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		fmt.Println("user deleted:", args[1])
	case "passwd":
		requireArg(args, 1, "nebbet user passwd <username>")
		if err := a.ChangePassword(args[1]); err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		fmt.Println("password updated:", args[1])
	default:
		fmt.Fprintf(os.Stderr, "unknown user subcommand %q\n", args[0])
		os.Exit(1)
	}
}

// ── helpers ───────────────────────────────────────────────────────────────────

func mustBuilder() *builder.Builder {
	if err := os.MkdirAll(dataDir, 0755); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
	meta, err := db.OpenMeta(metaDBPath)
	if err != nil {
		fmt.Fprintln(os.Stderr, "meta db:", err)
		os.Exit(1)
	}
	search, err := db.OpenSearch(searchDBPath)
	if err != nil {
		fmt.Fprintln(os.Stderr, "search db:", err)
		os.Exit(1)
	}
	return builder.New(contentDir, outputDir, meta, search)
}

func requireArg(args []string, n int, usage string) {
	if len(args) <= n {
		fmt.Fprintln(os.Stderr, "usage:", usage)
		os.Exit(1)
	}
}

func usage() {
	fmt.Fprintln(os.Stderr, `nebbet — static site generator with admin

Commands:
  build [--watch]         build all pages (optionally watch for changes)
  watch                   watch for changes and rebuild
  serve [--port N]        serve site + admin UI (default port 8080)
  user add <name>         add user to password file
  user list               list users
  user delete <name>      remove user
  user passwd <name>      change user password`)
}