package app

import (
	"context"
	"fmt"
	"io"
	"os"
	"slices"
	"sync"
	"time"

	"coopcloud.tech/abra/cli/internal"
	appPkg "coopcloud.tech/abra/pkg/app"
	"coopcloud.tech/abra/pkg/autocomplete"
	"coopcloud.tech/abra/pkg/client"
	"coopcloud.tech/abra/pkg/log"
	"coopcloud.tech/abra/pkg/upstream/stack"
	"github.com/docker/docker/api/types"
	containerTypes "github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/filters"
	"github.com/docker/docker/api/types/swarm"
	dockerClient "github.com/docker/docker/client"
	"github.com/spf13/cobra"
)

var AppLogsCommand = &cobra.Command{
	Use:     "logs <domain> [service] [flags]",
	Aliases: []string{"l"},
	Short:   "Tail app logs",
	Args:    cobra.RangeArgs(1, 2),
	ValidArgsFunction: func(
		cmd *cobra.Command,
		args []string,
		toComplete string) ([]string, cobra.ShellCompDirective) {
		switch l := len(args); l {
		case 0:
			return autocomplete.AppNameComplete()
		case 1:
			app, err := appPkg.Get(args[0])
			if err != nil {
				errMsg := fmt.Sprintf("autocomplete failed: %s", err)
				return []string{errMsg}, cobra.ShellCompDirectiveError
			}
			return autocomplete.ServiceNameComplete(app.Name)
		default:
			return nil, cobra.ShellCompDirectiveDefault
		}
	},
	Run: func(cmd *cobra.Command, args []string) {
		app := internal.ValidateApp(args)
		stackName := app.StackName()

		if err := app.Recipe.EnsureExists(); err != nil {
			log.Fatal(err)
		}

		cl, err := client.New(app.Server)
		if err != nil {
			log.Fatal(err)
		}

		deployMeta, err := stack.IsDeployed(context.Background(), cl, stackName)
		if err != nil {
			log.Fatal(err)
		}

		if !deployMeta.IsDeployed {
			log.Fatalf("%s is not deployed?", app.Name)
		}

		var serviceNames []string
		if len(args) == 2 {
			serviceNames = []string{args[1]}
		}

		if err = tailLogs(cl, app, serviceNames); err != nil {
			log.Fatal(err)
		}
	},
}

// tailLogs prints logs for the given app with optional service names to be
// filtered on. It also checks if the latest task is not runnning and then
// prints the past tasks.
func tailLogs(cl *dockerClient.Client, app appPkg.App, serviceNames []string) error {
	f, err := app.Filters(true, false, serviceNames...)
	if err != nil {
		return err
	}

	services, err := cl.ServiceList(context.Background(), types.ServiceListOptions{Filters: f})
	if err != nil {
		return err
	}

	var wg sync.WaitGroup
	for _, service := range services {
		filters := filters.NewArgs()
		filters.Add("name", service.Spec.Name)
		tasks, err := cl.TaskList(context.Background(), types.TaskListOptions{Filters: f})
		if err != nil {
			return err
		}
		if len(tasks) > 0 {
			// Need to sort the tasks by the CreatedAt field in the inverse order.
			// Otherwise they are in the reversed order and not sorted properly.
			slices.SortFunc[[]swarm.Task](tasks, func(t1, t2 swarm.Task) int {
				return int(t2.Meta.CreatedAt.Unix() - t1.Meta.CreatedAt.Unix())
			})
			lastTask := tasks[0].Status
			if lastTask.State != swarm.TaskStateRunning {
				for _, task := range tasks {
					log.Errorf("[%s] %s State %s: %s", service.Spec.Name, task.Meta.CreatedAt.Format(time.RFC3339), task.Status.State, task.Status.Err)
				}
			}
		}

		// Collect the logs in a go routine, so the logs from all services are
		// collected in parallel.
		wg.Add(1)
		go func(serviceID string) {
			logs, err := cl.ServiceLogs(context.Background(), serviceID, containerTypes.LogsOptions{
				ShowStderr: true,
				ShowStdout: !stdErr,
				Since:      sinceLogs,
				Until:      "",
				Timestamps: true,
				Follow:     true,
				Tail:       "20",
				Details:    false,
			})
			if err != nil {
				log.Fatal(err)
			}
			defer logs.Close()

			_, err = io.Copy(os.Stdout, logs)
			if err != nil && err != io.EOF {
				log.Fatal(err)
			}
		}(service.ID)
	}

	// Wait for all log streams to be closed.
	wg.Wait()

	return nil
}

var (
	stdErr    bool
	sinceLogs string
)

func init() {
	AppLogsCommand.Flags().BoolVarP(
		&stdErr,
		"stderr",
		"s",
		false,
		"only tail stderr",
	)

	AppLogsCommand.Flags().StringVarP(
		&sinceLogs,
		"since",
		"S",
		"",
		"tail logs since YYYY-MM-DDTHH:MM:SSZ",
	)
}