package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"syscall"
	"time"

	"yms-daemon/internal/backendupdate"
	"yms-daemon/internal/daemonapi"
	"yms-daemon/internal/daemonclient"
	"yms-daemon/internal/daemonserver"
	"yms-daemon/internal/deploymentconfig"
	"yms-daemon/internal/filestore"
	"yms-daemon/internal/hostnginx"
	"yms-daemon/internal/logging"
	"yms-daemon/internal/processlock"
	"yms-daemon/internal/runtimepaths"
	"yms-daemon/internal/systemd"
	"yms-daemon/internal/transaction"
)

const serviceBackend = "backend"

func main() {
	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer cancel()
	os.Exit(run(ctx, os.Args[1:], os.Stdout, os.Stderr))
}

func run(ctx context.Context, arguments []string, stdout io.Writer, stderr io.Writer) int {
	if len(arguments) == 0 {
		writeUsage(stderr)
		return 2
	}
	switch arguments[0] {
	case "serve":
		if len(arguments) != 1 {
			fmt.Fprintln(stderr, "serve does not accept arguments")
			return 2
		}
		if err := runServe(ctx); err != nil {
			fmt.Fprintln(stderr, "yms-daemon serve failed:", err)
			return 1
		}
		return 0
	case "update":
		request, err := parseUpdateArgs(arguments[1:], stderr)
		if err != nil {
			fmt.Fprintln(stderr, err)
			return 2
		}
		var progress func(daemonapi.Response)
		if !request.quite {
			progress = func(event daemonapi.Response) {
				writeUpdateProgress(stdout, event)
			}
		}
		response, err := daemonclient.Update(ctx, runtimepaths.Socket, request.service, request.inputType, request.file, progress)
		if err != nil {
			if response.TransactionID != "" {
				fmt.Fprintf(stderr, "transaction=%s state=%s error=%v\n", response.TransactionID, response.State, err)
			} else {
				fmt.Fprintln(stderr, "yms-daemon update failed:", err)
			}
			return 1
		}
		if !request.quite {
			fmt.Fprintf(stdout, "transaction=%s state=%s\n", response.TransactionID, response.State)
		}
		return 0
	case "restart":
		request, err := parseRestartArgs(arguments[1:], stderr)
		if err != nil {
			fmt.Fprintln(stderr, err)
			return 2
		}
		var progress func(daemonapi.Response)
		if !request.quite {
			progress = func(event daemonapi.Response) {
				writeUpdateProgress(stdout, event)
			}
		}
		response, err := daemonclient.Restart(ctx, runtimepaths.Socket, request.service, progress)
		if err != nil {
			if response.TransactionID != "" {
				fmt.Fprintf(stderr, "transaction=%s state=%s error=%v\n", response.TransactionID, response.State, err)
			} else {
				fmt.Fprintln(stderr, "yms-daemon restart failed:", err)
			}
			return 1
		}
		if !request.quite {
			fmt.Fprintf(stdout, "transaction=%s state=%s\n", response.TransactionID, response.State)
		}
		return 0
	case "help", "-h", "--help":
		writeUsage(stdout)
		return 0
	default:
		fmt.Fprintf(stderr, "unknown command: %s\n", arguments[0])
		writeUsage(stderr)
		return 2
	}
}

type updateArguments struct {
	service   string
	inputType string
	file      string
	quite     bool
}

type restartArguments struct {
	service string
	quite   bool
}

func parseUpdateArgs(arguments []string, output io.Writer) (updateArguments, error) {
	flags := flag.NewFlagSet("update", flag.ContinueOnError)
	flags.SetOutput(output)
	service := flags.String("service", "", "service to update")
	file := flags.String("f", "", "repack ZIP path")
	nativeJAR := flags.String("native-jar", "", "direct native backend JAR path")
	quite := flags.Bool("quite", false, "suppress progress and successful result output")
	if err := flags.Parse(arguments); err != nil {
		return updateArguments{}, err
	}
	if flags.NArg() != 0 {
		return updateArguments{}, errors.New("update does not accept positional arguments")
	}
	if *service != serviceBackend {
		return updateArguments{}, errors.New("--service currently accepts only backend")
	}
	if (*file == "") == (*nativeJAR == "") {
		return updateArguments{}, errors.New("exactly one of -f and --native-jar is required")
	}
	inputType := daemonapi.InputTypeRepackZIP
	inputFile := *file
	if *nativeJAR != "" {
		inputType = daemonapi.InputTypeNativeJAR
		inputFile = *nativeJAR
	}
	absoluteFile, err := filepath.Abs(inputFile)
	if err != nil {
		return updateArguments{}, fmt.Errorf("resolve update package path: %w", err)
	}
	info, err := os.Lstat(absoluteFile)
	if err != nil {
		return updateArguments{}, fmt.Errorf("inspect update package %s: %w", absoluteFile, err)
	}
	if !info.Mode().IsRegular() || info.Mode()&os.ModeSymlink != 0 {
		return updateArguments{}, fmt.Errorf("update package is not a direct regular file: %s", absoluteFile)
	}
	return updateArguments{service: *service, inputType: inputType, file: absoluteFile, quite: *quite}, nil
}

func parseRestartArgs(arguments []string, output io.Writer) (restartArguments, error) {
	flags := flag.NewFlagSet("restart", flag.ContinueOnError)
	flags.SetOutput(output)
	service := flags.String("service", "", "service to restart")
	quite := flags.Bool("quite", false, "suppress progress and successful result output")
	if err := flags.Parse(arguments); err != nil {
		return restartArguments{}, err
	}
	if flags.NArg() != 0 {
		return restartArguments{}, errors.New("restart does not accept positional arguments")
	}
	if *service != serviceBackend {
		return restartArguments{}, errors.New("--service currently accepts only backend")
	}
	return restartArguments{service: *service, quite: *quite}, nil
}

func runServe(ctx context.Context) (result error) {
	logger, logCloser, err := logging.New(runtimepaths.Log)
	if err != nil {
		return err
	}
	defer func() { result = errors.Join(result, logCloser.Close()) }()

	lock, err := processlock.Acquire(runtimepaths.Lock)
	if err != nil {
		return err
	}
	defer func() { result = errors.Join(result, lock.Close()) }()

	config, err := deploymentconfig.Load(deploymentconfig.DefaultPath)
	if err != nil {
		return err
	}
	store, err := transaction.OpenStore(ctx, runtimepaths.Database)
	if err != nil {
		return err
	}
	defer func() { result = errors.Join(result, store.Close()) }()
	coordinator, err := transaction.NewCoordinator(store, logger)
	if err != nil {
		return err
	}
	releaseStore, err := filestore.New(config.Backend.ReleaseDir)
	if err != nil {
		return err
	}
	units, err := systemd.NewSystemctl(config.Backend.SystemctlPath)
	if err != nil {
		return err
	}
	gateway, err := hostnginx.NewController(
		runtimepaths.HostNginxConfig,
		runtimepaths.HostNginxExecutable,
		config.Backend.SystemctlPath,
		runtimepaths.HostNginxService,
	)
	if err != nil {
		return err
	}
	httpClient := &http.Client{Timeout: 5 * time.Second}
	updater, err := backendupdate.New(config, runtimepaths.WorkRoot, store, coordinator, releaseStore, units, gateway, httpClient, logger)
	if err != nil {
		return err
	}
	server, err := daemonserver.New(runtimepaths.Socket, updater, logger)
	if err != nil {
		return err
	}
	return server.Serve(ctx)
}

func writeUsage(output io.Writer) {
	fmt.Fprintln(output, "usage:")
	fmt.Fprintln(output, "  yms-daemon serve")
	fmt.Fprintln(output, "  yms-daemon update --service backend -f <repack.zip> [--quite]")
	fmt.Fprintln(output, "  yms-daemon update --service backend --native-jar <backend.jar> [--quite]")
	fmt.Fprintln(output, "  yms-daemon restart --service backend [--quite]")
}

func writeUpdateProgress(output io.Writer, event daemonapi.Response) {
	state := event.State
	if state == "" {
		state = "INFO"
	}
	fmt.Fprintf(output, "%-14s %s\n", state, event.Message)
}