// tera-logd owns the authoritative userdata event journal.
package main

import (
	"errors"
	"log"
	"net"
	"os"
	"os/signal"
	"path/filepath"
	"strconv"
	"syscall"

	"tera-clone/services/tera-api/internal/logservice"
	"tera-clone/services/tera-api/internal/logstorage"
	"tera-clone/services/tera-api/internal/storage/capacity"
)

func main() {
	policyPath := getenv("TERA_LOGD_STORAGE_POLICY", "/userdata/storage-layout.json")
	policy, err := capacity.LoadPolicy(policyPath)
	if err != nil {
		log.Fatalf("tera-logd storage policy setup failed: %v", err)
	}
	store, err := logstorage.Open(logstorage.Options{
		Root:            getenv("TERA_LOGD_ROOT", "/userdata/log"),
		SegmentBytes:    getenvInt64("TERA_LOGD_SEGMENT_BYTES", 4<<20),
		AuditCapBytes:   policy.CapsBytes.AuditLogs,
		SystemCapBytes:  policy.CapsBytes.SystemEvents,
		PortCapBytes:    policy.CapsBytes.PortEvents,
		IndexCapBytes:   policy.CapsBytes.StateAndIndexes,
		GlobalFreeFloor: policy.CapsBytes.GlobalFreeFloor,
	})
	if err != nil {
		log.Fatalf("tera-logd store setup failed: %v", err)
	}

	socketPath := getenv("TERA_LOGD_SOCKET", logservice.DefaultSocketPath)
	listener, err := listen(socketPath)
	if err != nil {
		log.Fatalf("tera-logd socket setup failed: %v", err)
	}
	defer func() {
		_ = listener.Close()
		_ = os.Remove(socketPath)
	}()

	server := logservice.Server{Store: store}
	done := make(chan error, 1)
	go func() { done <- server.Serve(listener) }()
	log.Printf("tera-logd serving authoritative log storage on %s", socketPath)

	signals := make(chan os.Signal, 1)
	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
	select {
	case signal := <-signals:
		log.Printf("tera-logd stopping after %s", signal)
		_ = listener.Close()
		if err := <-done; err != nil {
			log.Printf("tera-logd stop error: %v", err)
		}
	case err := <-done:
		if err != nil {
			log.Fatalf("tera-logd failed: %v", err)
		}
	}
}

func listen(socketPath string) (net.Listener, error) {
	if socketPath == "" || !filepath.IsAbs(socketPath) {
		return nil, errors.New("TERA_LOGD_SOCKET must be an absolute path")
	}
	if err := os.MkdirAll(filepath.Dir(socketPath), 0o750); err != nil {
		return nil, err
	}
	if info, err := os.Lstat(socketPath); err == nil {
		if info.Mode()&os.ModeSocket == 0 {
			return nil, errors.New("refusing to replace non-socket log service path")
		}
		if err := os.Remove(socketPath); err != nil {
			return nil, err
		}
	} else if !os.IsNotExist(err) {
		return nil, err
	}
	listener, err := net.Listen("unix", socketPath)
	if err != nil {
		return nil, err
	}
	if err := os.Chmod(socketPath, 0o660); err != nil {
		_ = listener.Close()
		return nil, err
	}
	return listener, nil
}

func getenv(key, fallback string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return fallback
}

func getenvInt64(key string, fallback int64) int64 {
	value, err := strconv.ParseInt(os.Getenv(key), 10, 64)
	if err != nil || value <= 0 {
		return fallback
	}
	return value
}