package runner

import (
	"context"
	"embed"
	"fmt"
	"io"
	"io/fs"
	"os"
	"path"
	"path/filepath"
	"regexp"
	"runtime"
	"strings"

	"github.com/kballard/go-shellquote"
	"github.com/nektos/act/pkg/common"
	"github.com/nektos/act/pkg/container"
	"github.com/nektos/act/pkg/model"
	log "github.com/sirupsen/logrus"
)

type actionStep interface {
	step

	getActionModel() *model.Action
}

type readAction func(step *model.Step, actionDir string, actionPath string, readFile actionYamlReader, writeFile fileWriter) (*model.Action, error)

type actionYamlReader func(filename string) (io.Reader, io.Closer, error)
type fileWriter func(filename string, data []byte, perm fs.FileMode) error

type runAction func(step actionStep, actionDir string, remoteAction *remoteAction) common.Executor

//go:embed res/trampoline.js
var trampoline embed.FS

func readActionImpl(step *model.Step, actionDir string, actionPath string, readFile actionYamlReader, writeFile fileWriter) (*model.Action, error) {
	reader, closer, err := readFile("action.yml")
	if os.IsNotExist(err) {
		reader, closer, err = readFile("action.yaml")
		if err != nil {
			if _, closer, err2 := readFile("Dockerfile"); err2 == nil {
				closer.Close()
				action := &model.Action{
					Name: "(Synthetic)",
					Runs: model.ActionRuns{
						Using: "docker",
						Image: "Dockerfile",
					},
				}
				log.Debugf("Using synthetic action %v for Dockerfile", action)
				return action, nil
			}
			if step.With != nil {
				if val, ok := step.With["args"]; ok {
					var b []byte
					if b, err = trampoline.ReadFile("res/trampoline.js"); err != nil {
						return nil, err
					}
					err2 := writeFile(filepath.Join(actionDir, actionPath, "trampoline.js"), b, 0400)
					if err2 != nil {
						return nil, err2
					}
					action := &model.Action{
						Name: "(Synthetic)",
						Inputs: map[string]model.Input{
							"cwd": {
								Description: "(Actual working directory)",
								Required:    false,
								Default:     filepath.Join(actionDir, actionPath),
							},
							"command": {
								Description: "(Actual program)",
								Required:    false,
								Default:     val,
							},
						},
						Runs: model.ActionRuns{
							Using: "node12",
							Main:  "trampoline.js",
						},
					}
					log.Debugf("Using synthetic action %v", action)
					return action, nil
				}
			}
			return nil, err
		}
	} else if err != nil {
		return nil, err
	}
	defer closer.Close()

	action, err := model.ReadAction(reader)
	log.Debugf("Read action %v from '%s'", action, "Unknown")
	return action, err
}

func runActionImpl(step actionStep, actionDir string, remoteAction *remoteAction) common.Executor {
	rc := step.getRunContext()
	stepModel := step.getStepModel()
	return func(ctx context.Context) error {
		actionPath := ""
		if remoteAction != nil && remoteAction.Path != "" {
			actionPath = remoteAction.Path
		}
		action := step.getActionModel()
		log.Debugf("About to run action %v", action)

		if remoteAction != nil {
			rc.ActionRepository = fmt.Sprintf("%s/%s", remoteAction.Org, remoteAction.Repo)
			rc.ActionRef = remoteAction.Ref
		} else {
			rc.ActionRepository = ""
			rc.ActionRef = ""
		}
		defer (func() {
			// cleanup after the action is done, to avoid side-effects in
			// the next step/action
			rc.ActionRepository = ""
			rc.ActionRef = ""
		})()

		// we need to merge with github-env again, since at the step setup
		// time, we don't have all environment prepared
		mergeIntoMap(step.getEnv(), rc.withGithubEnv(map[string]string{}))

		populateEnvsFromInput(step.getEnv(), action, rc)

		actionLocation := path.Join(actionDir, actionPath)
		actionName, containerActionDir := getContainerActionPaths(stepModel, actionLocation, rc)

		log.Debugf("type=%v actionDir=%s actionPath=%s workdir=%s actionCacheDir=%s actionName=%s containerActionDir=%s", stepModel.Type(), actionDir, actionPath, rc.Config.Workdir, rc.ActionCacheDir(), actionName, containerActionDir)

		maybeCopyToActionDir := func() error {
			if stepModel.Type() != model.StepTypeUsesActionRemote {
				return nil
			}
			if err := removeGitIgnore(actionDir); err != nil {
				return err
			}

			var containerActionDirCopy string
			containerActionDirCopy = strings.TrimSuffix(containerActionDir, actionPath)
			log.Debug(containerActionDirCopy)

			if !strings.HasSuffix(containerActionDirCopy, `/`) {
				containerActionDirCopy += `/`
			}
			return rc.JobContainer.CopyDir(containerActionDirCopy, actionDir+"/", rc.Config.UseGitIgnore)(ctx)
		}

		switch action.Runs.Using {
		case model.ActionRunsUsingNode12, model.ActionRunsUsingNode16:
			if err := maybeCopyToActionDir(); err != nil {
				return err
			}
			containerArgs := []string{"node", path.Join(containerActionDir, action.Runs.Main)}
			log.Debugf("executing remote job container: %s", containerArgs)
			return rc.execJobContainer(containerArgs, *step.getEnv(), "", "")(ctx)
		case model.ActionRunsUsingDocker:
			location := actionLocation
			if remoteAction == nil {
				location = containerActionDir
			}
			return execAsDocker(ctx, step, actionName, location, remoteAction == nil)
		case model.ActionRunsUsingComposite:
			if err := maybeCopyToActionDir(); err != nil {
				return err
			}
			return execAsComposite(step, containerActionDir)(ctx)
		default:
			return fmt.Errorf(fmt.Sprintf("The runs.using key must be one of: %v, got %s", []string{
				model.ActionRunsUsingDocker,
				model.ActionRunsUsingNode12,
				model.ActionRunsUsingNode16,
				model.ActionRunsUsingComposite,
			}, action.Runs.Using))
		}
	}
}

// https://github.com/nektos/act/issues/228#issuecomment-629709055
// files in .gitignore are not copied in a Docker container
// this causes issues with actions that ignore other important resources
// such as `node_modules` for example
func removeGitIgnore(directory string) error {
	gitIgnorePath := path.Join(directory, ".gitignore")
	if _, err := os.Stat(gitIgnorePath); err == nil {
		// .gitignore exists
		log.Debugf("Removing %s before docker cp", gitIgnorePath)
		err := os.Remove(gitIgnorePath)
		if err != nil {
			return err
		}
	}
	return nil
}

// TODO: break out parts of function to reduce complexicity
// nolint:gocyclo
func execAsDocker(ctx context.Context, step actionStep, actionName string, basedir string, localAction bool) error {
	rc := step.getRunContext()
	action := step.getActionModel()

	var prepImage common.Executor
	var image string
	if strings.HasPrefix(action.Runs.Image, "docker://") {
		image = strings.TrimPrefix(action.Runs.Image, "docker://")
	} else {
		// "-dockeraction" enshures that "./", "./test " won't get converted to "act-:latest", "act-test-:latest" which are invalid docker image names
		image = fmt.Sprintf("%s-dockeraction:%s", regexp.MustCompile("[^a-zA-Z0-9]").ReplaceAllString(actionName, "-"), "latest")
		image = fmt.Sprintf("act-%s", strings.TrimLeft(image, "-"))
		image = strings.ToLower(image)
		contextDir := filepath.Join(basedir, action.Runs.Main)

		anyArchExists, err := container.ImageExistsLocally(ctx, image, "any")
		if err != nil {
			return err
		}

		correctArchExists, err := container.ImageExistsLocally(ctx, image, rc.Config.ContainerArchitecture)
		if err != nil {
			return err
		}

		if anyArchExists && !correctArchExists {
			wasRemoved, err := container.RemoveImage(ctx, image, true, true)
			if err != nil {
				return err
			}
			if !wasRemoved {
				return fmt.Errorf("failed to remove image '%s'", image)
			}
		}

		if !correctArchExists || rc.Config.ForceRebuild {
			log.Debugf("image '%s' for architecture '%s' will be built from context '%s", image, rc.Config.ContainerArchitecture, contextDir)
			var actionContainer container.Container
			if localAction {
				actionContainer = rc.JobContainer
			}
			prepImage = container.NewDockerBuildExecutor(container.NewDockerBuildExecutorInput{
				ContextDir: contextDir,
				ImageTag:   image,
				Container:  actionContainer,
				Platform:   rc.Config.ContainerArchitecture,
			})
		} else {
			log.Debugf("image '%s' for architecture '%s' already exists", image, rc.Config.ContainerArchitecture)
		}
	}
	eval := rc.NewStepExpressionEvaluator(step)
	cmd, err := shellquote.Split(eval.Interpolate(step.getStepModel().With["args"]))
	if err != nil {
		return err
	}
	if len(cmd) == 0 {
		cmd = action.Runs.Args
		evalDockerArgs(step, action, &cmd)
	}
	entrypoint := strings.Fields(eval.Interpolate(step.getStepModel().With["entrypoint"]))
	if len(entrypoint) == 0 {
		if action.Runs.Entrypoint != "" {
			entrypoint, err = shellquote.Split(action.Runs.Entrypoint)
			if err != nil {
				return err
			}
		} else {
			entrypoint = nil
		}
	}
	stepContainer := newStepContainer(ctx, step, image, cmd, entrypoint)
	return common.NewPipelineExecutor(
		prepImage,
		stepContainer.Pull(rc.Config.ForcePull),
		stepContainer.Remove().IfBool(!rc.Config.ReuseContainers),
		stepContainer.Create(rc.Config.ContainerCapAdd, rc.Config.ContainerCapDrop),
		stepContainer.Start(true),
	).Finally(
		stepContainer.Remove().IfBool(!rc.Config.ReuseContainers),
	).Finally(stepContainer.Close())(ctx)
}

func evalDockerArgs(step step, action *model.Action, cmd *[]string) {
	rc := step.getRunContext()
	stepModel := step.getStepModel()
	oldInputs := rc.Inputs
	defer func() {
		rc.Inputs = oldInputs
	}()
	inputs := make(map[string]interface{})
	eval := rc.NewExpressionEvaluator()
	// Set Defaults
	for k, input := range action.Inputs {
		inputs[k] = eval.Interpolate(input.Default)
	}
	if stepModel.With != nil {
		for k, v := range stepModel.With {
			inputs[k] = eval.Interpolate(v)
		}
	}
	rc.Inputs = inputs
	stepEE := rc.NewStepExpressionEvaluator(step)
	for i, v := range *cmd {
		(*cmd)[i] = stepEE.Interpolate(v)
	}
	mergeIntoMap(step.getEnv(), action.Runs.Env)

	ee := rc.NewStepExpressionEvaluator(step)
	for k, v := range *step.getEnv() {
		(*step.getEnv())[k] = ee.Interpolate(v)
	}
}

func newStepContainer(ctx context.Context, step step, image string, cmd []string, entrypoint []string) container.Container {
	rc := step.getRunContext()
	stepModel := step.getStepModel()
	rawLogger := common.Logger(ctx).WithField("raw_output", true)
	logWriter := common.NewLineWriter(rc.commandHandler(ctx), func(s string) bool {
		if rc.Config.LogOutput {
			rawLogger.Infof("%s", s)
		} else {
			rawLogger.Debugf("%s", s)
		}
		return true
	})
	envList := make([]string, 0)
	for k, v := range *step.getEnv() {
		envList = append(envList, fmt.Sprintf("%s=%s", k, v))
	}

	envList = append(envList, fmt.Sprintf("%s=%s", "RUNNER_TOOL_CACHE", "/opt/hostedtoolcache"))
	envList = append(envList, fmt.Sprintf("%s=%s", "RUNNER_OS", "Linux"))
	envList = append(envList, fmt.Sprintf("%s=%s", "RUNNER_TEMP", "/tmp"))

	binds, mounts := rc.GetBindsAndMounts()

	stepContainer := container.NewContainer(&container.NewContainerInput{
		Cmd:         cmd,
		Entrypoint:  entrypoint,
		WorkingDir:  rc.Config.ContainerWorkdir(),
		Image:       image,
		Username:    rc.Config.Secrets["DOCKER_USERNAME"],
		Password:    rc.Config.Secrets["DOCKER_PASSWORD"],
		Name:        createContainerName(rc.jobContainerName(), stepModel.ID),
		Env:         envList,
		Mounts:      mounts,
		NetworkMode: fmt.Sprintf("container:%s", rc.jobContainerName()),
		Binds:       binds,
		Stdout:      logWriter,
		Stderr:      logWriter,
		Privileged:  rc.Config.Privileged,
		UsernsMode:  rc.Config.UsernsMode,
		Platform:    rc.Config.ContainerArchitecture,
	})
	return stepContainer
}

func execAsComposite(step actionStep, containerActionDir string) common.Executor {
	rc := step.getRunContext()
	action := step.getActionModel()

	return func(ctx context.Context) error {
		eval := rc.NewExpressionEvaluator()

		inputs := make(map[string]interface{})
		for k, input := range action.Inputs {
			inputs[k] = eval.Interpolate(input.Default)
		}
		if step.getStepModel().With != nil {
			for k, v := range step.getStepModel().With {
				inputs[k] = eval.Interpolate(v)
			}
		}

		env := make(map[string]string)
		for k, v := range rc.Env {
			env[k] = eval.Interpolate(v)
		}
		for k, v := range step.getStepModel().Environment() {
			env[k] = eval.Interpolate(v)
		}

		// run with the global config but without secrets
		configCopy := *rc.Config
		configCopy.Secrets = nil

		// create a run context for the composite action to run in
		compositerc := &RunContext{
			Name:    rc.Name,
			JobName: rc.JobName,
			Run: &model.Run{
				JobID: "composite-job",
				Workflow: &model.Workflow{
					Name: rc.Run.Workflow.Name,
					Jobs: map[string]*model.Job{
						"composite-job": {},
					},
				},
			},
			Config:           &configCopy,
			StepResults:      map[string]*model.StepResult{},
			JobContainer:     rc.JobContainer,
			Inputs:           inputs,
			ActionPath:       containerActionDir,
			ActionRepository: rc.ActionRepository,
			ActionRef:        rc.ActionRef,
			Env:              env,
			Masks:            rc.Masks,
			ExtraPath:        rc.ExtraPath,
		}

		ctx = WithCompositeLogger(ctx, &compositerc.Masks)

		// We need to inject a composite RunContext related command
		// handler into the current running job container
		// We need this, to support scoping commands to the composite action
		// executing.
		rawLogger := common.Logger(ctx).WithField("raw_output", true)
		logWriter := common.NewLineWriter(compositerc.commandHandler(ctx), func(s string) bool {
			if rc.Config.LogOutput {
				rawLogger.Infof("%s", s)
			} else {
				rawLogger.Debugf("%s", s)
			}
			return true
		})
		oldout, olderr := compositerc.JobContainer.ReplaceLogWriter(logWriter, logWriter)
		defer (func() {
			rc.JobContainer.ReplaceLogWriter(oldout, olderr)
		})()

		err := compositerc.compositeExecutor(action)(ctx)

		// Map outputs from composite RunContext to job RunContext
		eval = compositerc.NewExpressionEvaluator()
		for outputName, output := range action.Outputs {
			rc.setOutput(ctx, map[string]string{
				"name": outputName,
			}, eval.Interpolate(output.Value))
		}

		rc.Masks = compositerc.Masks
		rc.ExtraPath = compositerc.ExtraPath

		return err
	}
}

// Executor returns a pipeline executor for all the steps in the job
func (rc *RunContext) compositeExecutor(action *model.Action) common.Executor {
	steps := make([]common.Executor, 0)

	sf := &stepFactoryImpl{}

	for i, step := range action.Runs.Steps {
		if step.ID == "" {
			step.ID = fmt.Sprintf("%d", i)
		}

		// create a copy of the step, since this composite action could
		// run multiple times and we might modify the instance
		stepcopy := step

		step, err := sf.newStep(&stepcopy, rc)
		if err != nil {
			return common.NewErrorExecutor(err)
		}
		stepExec := common.NewPipelineExecutor(step.pre(), step.main(), step.post())

		steps = append(steps, func(ctx context.Context) error {
			err := stepExec(ctx)
			if err != nil {
				common.Logger(ctx).Errorf("%v", err)
				common.SetJobError(ctx, err)
			} else if ctx.Err() != nil {
				common.Logger(ctx).Errorf("%v", ctx.Err())
				common.SetJobError(ctx, ctx.Err())
			}
			return nil
		})
	}

	steps = append(steps, common.JobError)
	return func(ctx context.Context) error {
		return common.NewPipelineExecutor(steps...)(common.WithJobErrorContainer(ctx))
	}
}

func populateEnvsFromInput(env *map[string]string, action *model.Action, rc *RunContext) {
	eval := rc.NewExpressionEvaluator()
	for inputID, input := range action.Inputs {
		envKey := regexp.MustCompile("[^A-Z0-9-]").ReplaceAllString(strings.ToUpper(inputID), "_")
		envKey = fmt.Sprintf("INPUT_%s", envKey)
		if _, ok := (*env)[envKey]; !ok {
			(*env)[envKey] = eval.Interpolate(input.Default)
		}
	}
}

func getContainerActionPaths(step *model.Step, actionDir string, rc *RunContext) (string, string) {
	actionName := ""
	containerActionDir := "."
	if step.Type() != model.StepTypeUsesActionRemote {
		actionName = getOsSafeRelativePath(actionDir, rc.Config.Workdir)
		containerActionDir = rc.Config.ContainerWorkdir() + "/" + actionName
		actionName = "./" + actionName
	} else if step.Type() == model.StepTypeUsesActionRemote {
		actionName = getOsSafeRelativePath(actionDir, rc.ActionCacheDir())
		containerActionDir = ActPath + "/actions/" + actionName
	}

	if actionName == "" {
		actionName = filepath.Base(actionDir)
		if runtime.GOOS == "windows" {
			actionName = strings.ReplaceAll(actionName, "\\", "/")
		}
	}
	return actionName, containerActionDir
}

func getOsSafeRelativePath(s, prefix string) string {
	actionName := strings.TrimPrefix(s, prefix)
	if runtime.GOOS == "windows" {
		actionName = strings.ReplaceAll(actionName, "\\", "/")
	}
	actionName = strings.TrimPrefix(actionName, "/")

	return actionName
}