package remnawave

// Centralized (NordVPN-style) provisioning: the panel address and API token
// are baked into the binary at build time, so every user gets configs
// automatically and cannot change the panel.
//
// build.bat copies configs/remnawave-api.json into embeddedcfg/ before
// `go build`; the copy is gitignored so credentials never land in the repo.
// Without the embedded file the app falls back to the external
// configs/remnawave-api.json (developer mode).

import (
	"crypto/rand"
	"embed"
	"encoding/hex"
	"fmt"
	"os"
	"time"
)

//go:embed embeddedcfg
var embeddedCfgFS embed.FS

// EmbeddedAdminConfig returns the admin config baked into the binary,
// or nil when this build has no embedded credentials.
func EmbeddedAdminConfig() *AdminConfig {
	data, err := embeddedCfgFS.ReadFile("embeddedcfg/remnawave-api.json")
	if err != nil {
		return nil
	}
	cfg, err := parseAdminConfig(data)
	if err != nil {
		return nil
	}
	return cfg
}

// GenerateUsername makes a unique panel username for silent auto-provisioning
// (users never type anything): "fox_" + 10 hex chars, e.g. fox_3fa9c02b71.
func GenerateUsername() string {
	var b [5]byte
	if _, err := rand.Read(b[:]); err != nil {
		// Keep within Remnawave's 6–34 char username limit.
		s := fmt.Sprintf("fox_%x%x", os.Getpid()&0xffff, time.Now().UnixNano()&0xffffffff)
		if len(s) > 34 {
			s = s[:34]
		}
		return s
	}
	return "fox_" + hex.EncodeToString(b[:])
}