package component

import (
	"context"
	"errors"
	"fmt"
	"time"

	devfilev1 "github.com/devfile/api/v2/pkg/apis/workspaces/v1alpha2"
	"k8s.io/klog"

	"github.com/redhat-developer/odo/pkg/exec"
	"github.com/redhat-developer/odo/pkg/log"
	"github.com/redhat-developer/odo/pkg/platform"
	"github.com/redhat-developer/odo/pkg/remotecmd"
	"github.com/redhat-developer/odo/pkg/task"
	"github.com/redhat-developer/odo/pkg/util"
)

const numberOfLinesToOutputLog = 100

// ExecuteRunCommand executes a Devfile command in the specified pod
// If componentExists, the previous instance of the command will be stopped before (if hotReloadCapable is not set)
func ExecuteRunCommand(ctx context.Context, execClient exec.Client, platformClient platform.Client, devfileCmd devfilev1.Command, componentExists bool, podName string, appName string, componentName string) error {
	remoteProcessHandler := remotecmd.NewKubeExecProcessHandler(execClient)

	statusHandlerFunc := func(s *log.Status) remotecmd.CommandOutputHandler {
		return func(status remotecmd.RemoteProcessStatus, stdout []string, stderr []string, err error) {
			switch status {
			case remotecmd.Starting:
				// Creating with no spin because the command could be long-running, and we cannot determine when it will end.
				s.Start(fmt.Sprintf("Executing the application (command: %s)", devfileCmd.Id), true)
			case remotecmd.Stopped, remotecmd.Errored:
				s.EndWithStatus(fmt.Sprintf("Finished executing the application (command: %s)", devfileCmd.Id), status == remotecmd.Stopped)
				if err != nil {
					klog.V(2).Infof("error while running background command: %v", err)
				}
			}
		}
	}

	// Spinner created but not started yet.
	// It will be displayed when the statusHandlerFunc function is called with the "Starting" state.
	spinner := log.NewStatus(log.GetStdout())

	// if we need to restart, issue the remote process handler command to stop all running commands first.
	// We do not need to restart Hot reload capable commands.
	if componentExists {
		if devfileCmd.Exec == nil || !util.SafeGetBool(devfileCmd.Exec.HotReloadCapable) {
			klog.V(2).Infof("restart required for command %s", devfileCmd.Id)

			cmdDef, err := devfileCommandToRemoteCmdDefinition(devfileCmd)
			if err != nil {
				return err
			}

			err = remoteProcessHandler.StopProcessForCommand(ctx, cmdDef, podName, devfileCmd.Exec.Component)
			if err != nil {
				return err
			}

			if err = remoteProcessHandler.StartProcessForCommand(ctx, cmdDef, podName, devfileCmd.Exec.Component, statusHandlerFunc(spinner)); err != nil {
				return err
			}
		} else {
			klog.V(2).Infof("command is hot-reload capable, not restarting %s", devfileCmd.Id)
		}
	} else {
		cmdDef, err := devfileCommandToRemoteCmdDefinition(devfileCmd)
		if err != nil {
			return err
		}

		if err := remoteProcessHandler.StartProcessForCommand(ctx, cmdDef, podName, devfileCmd.Exec.Component, statusHandlerFunc(spinner)); err != nil {
			return err
		}
	}

	retrySchedule := []time.Duration{
		5 * time.Second,
		6 * time.Second,
		9 * time.Second,
	}
	var totalWaitTime float64
	for _, s := range retrySchedule {
		totalWaitTime += s.Seconds()
	}

	_, err := task.NewRetryable(fmt.Sprintf("process for command %q", devfileCmd.Id), func() (bool, interface{}, error) {
		klog.V(4).Infof("checking if process for command %q is running", devfileCmd.Id)
		remoteProcess, err := remoteProcessHandler.GetProcessInfoForCommand(ctx, remotecmd.CommandDefinition{Id: devfileCmd.Id}, podName, devfileCmd.Exec.Component)
		if err != nil {
			return false, nil, err
		}
		isRunningOrDone := remoteProcess.Status == remotecmd.Running ||
			remoteProcess.Status == remotecmd.Stopped ||
			remoteProcess.Status == remotecmd.Errored
		return isRunningOrDone, nil, err
	}).RetryWithSchedule(retrySchedule, false)
	if err != nil {
		return err
	}

	return checkRemoteCommandStatus(ctx, execClient, platformClient, devfileCmd, podName, appName, componentName, fmt.Sprintf("Devfile command %q exited with an error status in %.0f second(s)", devfileCmd.Id, totalWaitTime))
}

// devfileCommandToRemoteCmdDefinition builds and returns a new remotecmd.CommandDefinition object from the specified devfileCmd.
// An error is returned for non-exec Devfile commands.
func devfileCommandToRemoteCmdDefinition(devfileCmd devfilev1.Command) (remotecmd.CommandDefinition, error) {
	if devfileCmd.Exec == nil {
		return remotecmd.CommandDefinition{}, errors.New(" only Exec commands are supported")
	}

	envVars := make([]remotecmd.CommandEnvVar, 0, len(devfileCmd.Exec.Env))
	for _, e := range devfileCmd.Exec.Env {
		envVars = append(envVars, remotecmd.CommandEnvVar{Key: e.Name, Value: e.Value})
	}

	return remotecmd.CommandDefinition{
		Id:         devfileCmd.Id,
		WorkingDir: devfileCmd.Exec.WorkingDir,
		EnvVars:    envVars,
		CmdLine:    devfileCmd.Exec.CommandLine,
	}, nil
}

// checkRemoteCommandStatus checks if the command is running .
// if the command is not in a running state, we fetch the last 20 lines of the component's log and display it
func checkRemoteCommandStatus(ctx context.Context, execClient exec.Client, platformClient platform.Client, command devfilev1.Command, podName string, appName string, componentName string, notRunningMessage string) error {
	remoteProcessHandler := remotecmd.NewKubeExecProcessHandler(execClient)
	remoteProcess, err := remoteProcessHandler.GetProcessInfoForCommand(ctx, remotecmd.CommandDefinition{Id: command.Id}, podName, command.Exec.Component)
	if err != nil {
		return err
	}

	if remoteProcess.Status != remotecmd.Running && remoteProcess.Status != remotecmd.Stopped {
		log.Warningf(notRunningMessage)
		log.Warningf("Last %d lines of log:", numberOfLinesToOutputLog)

		rd, err := Log(platformClient, componentName, appName, false, command)
		if err != nil {
			return err
		}

		// Use GetStderr in order to make sure that colour output is correct
		// on non-TTY terminals
		err = util.DisplayLog(false, rd, log.GetStderr(), componentName, numberOfLinesToOutputLog)
		if err != nil {
			return err
		}
	}
	return nil
}