package runner

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"path"
	"regexp"
	"runtime"
	"strings"

	"github.com/kballard/go-shellquote"

	"gitea.com/gitea/act_runner/pkg/common"
	"gitea.com/gitea/act_runner/pkg/container"
	"gitea.com/gitea/act_runner/pkg/model"
)

type actionStep interface {
	step

	getActionModel() *model.Action
	getCompositeRunContext(context.Context) *RunContext
	getCompositeSteps() *compositeSteps
	getContainerActionPaths() (actionName string, containerActionDir string)
	getTarArchive(ctx context.Context, src string) (io.ReadCloser, error)
	getActionPath() string
	maybeCopyToActionDir(ctx context.Context) error
}

type readAction func(ctx context.Context, step *model.Step, readFile actionYamlReader, config model.ActionConfig) (*model.Action, error)

type actionYamlReader func(filename string) (io.Reader, io.Closer, error)

type runAction func(step actionStep) common.Executor

func readActionImpl(ctx context.Context, step *model.Step, readFile actionYamlReader, config model.ActionConfig) (*model.Action, error) {
	logger := common.Logger(ctx)
	allErrors := []error{}
	addError := func(fileName string, err error) {
		if err != nil {
			allErrors = append(allErrors, fmt.Errorf("failed to read '%s' from action '%s': %w", fileName, step.String(), err))
		} else {
			// One successful read, clear error state
			allErrors = nil
		}
	}
	reader, closer, err := readFile("action.yml")
	addError("action.yml", err)
	if os.IsNotExist(err) {
		reader, closer, err = readFile("action.yaml")
		addError("action.yaml", err)
		if os.IsNotExist(err) {
			_, closer, err := readFile("Dockerfile")
			addError("Dockerfile", err)
			if err == nil {
				closer.Close()
				action := &model.Action{
					Name: "(Synthetic)",
					Runs: model.ActionRuns{
						Using: "docker",
						Image: "Dockerfile",
					},
				}
				logger.Debugf("Using synthetic action %v for Dockerfile", action)
				return action, nil
			}
		}
	}
	if allErrors != nil {
		return nil, errors.Join(allErrors...)
	}
	defer closer.Close()

	action, err := model.ReadAction(reader, config)
	logger.Debugf("Read action %v", action)
	return action, err
}

func runActionImpl(step actionStep) common.Executor {
	rc := step.getRunContext()
	stepModel := step.getStepModel()

	return func(ctx context.Context) error {
		logger := common.Logger(ctx)
		actionPath := step.getActionPath()

		action := step.getActionModel()
		logger.Debugf("About to run action %v", action)

		err := setupActionEnv(ctx, step)
		if err != nil {
			return err
		}

		actionName, containerActionDir := step.getContainerActionPaths()

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

		x := action.Runs.Using
		switch {
		case x.IsNode():
			if err := step.maybeCopyToActionDir(ctx); err != nil {
				return err
			}
			containerArgs := []string{rc.GetNodeToolFullPath(ctx), path.Join(containerActionDir, action.Runs.Main)}
			logger.Debugf("executing remote job container: %s", containerArgs)

			rc.ApplyExtraPath(ctx, step.getEnv())

			return rc.execJobContainer(containerArgs, *step.getEnv(), "", "")(ctx)
		case x.IsDocker():
			return execAsDocker(ctx, step, actionName, actionPath, "entrypoint")
		case x.IsComposite():
			if err := step.maybeCopyToActionDir(ctx); err != nil {
				return err
			}

			return execAsComposite(step)(ctx)
		default:
			return fmt.Errorf("the runs.using key must be one of: %v, got %s", []string{
				model.ActionRunsUsingDocker,
				model.ActionRunsUsingNode,
				model.ActionRunsUsingComposite,
			}, action.Runs.Using)
		}
	}
}

func setupActionEnv(ctx context.Context, step actionStep) error {
	rc := step.getRunContext()

	// A few fields in the environment (e.g. GITHUB_ACTION_REPOSITORY)
	// are dependent on the action. That means we can complete the
	// setup only after resolving the whole action model and cloning
	// the action
	rc.withGithubEnv(ctx, step.getGithubContext(ctx), *step.getEnv())
	populateEnvsFromSavedState(step.getEnv(), step, rc)
	populateEnvsFromInput(ctx, step.getEnv(), step.getActionModel(), rc)

	return nil
}

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

	var prepImage common.Executor
	var image string
	forcePull := false
	if strings.HasPrefix(action.Runs.Image, "docker://") {
		image = strings.TrimPrefix(action.Runs.Image, "docker://")
		// Apply forcePull only for prebuild docker images
		forcePull = rc.Config.ForcePull
	} else {
		// "-dockeraction" ensures 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, fileName := path.Split(path.Join(subpath, action.Runs.Image))

		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 {
			logger.Debugf("image '%s' for architecture '%s' will be built from context '%s", image, rc.Config.ContainerArchitecture, contextDir)
			buildContext, err := step.getTarArchive(ctx, contextDir+".")
			if err != nil {
				return err
			}
			defer buildContext.Close()
			prepImage = container.NewDockerBuildExecutor(container.NewDockerBuildExecutorInput{
				Dockerfile:   fileName,
				ImageTag:     image,
				BuildContext: buildContext,
				Platform:     rc.Config.ContainerArchitecture,
			})
		} else {
			logger.Debugf("image '%s' for architecture '%s' already exists", image, rc.Config.ContainerArchitecture)
		}
	}
	eval := rc.NewStepExpressionEvaluator(ctx, step)
	cmd, err := shellquote.Split(eval.Interpolate(ctx, step.getStepModel().With["args"]))
	if err != nil {
		return err
	}
	if len(cmd) == 0 {
		cmd = action.Runs.Args
		evalDockerArgs(ctx, step, action, &cmd)
	}

	entrypoint := strings.Fields(eval.Interpolate(ctx, step.getStepModel().With[entrypointType]))
	if len(entrypoint) == 0 {
		if entrypointType == "pre-entrypoint" && action.Runs.PreEntrypoint != "" {
			entrypoint, err = shellquote.Split(action.Runs.PreEntrypoint)

			if err != nil {
				return err
			}
		} else if entrypointType == "entrypoint" && action.Runs.Entrypoint != "" {
			entrypoint, err = shellquote.Split(action.Runs.Entrypoint)
			if err != nil {
				return err
			}
		} else if entrypointType == "post-entrypoint" && action.Runs.PostEntrypoint != "" {
			entrypoint, err = shellquote.Split(action.Runs.PostEntrypoint)
			if err != nil {
				return err
			}
		} else {
			entrypoint = nil
		}
	}
	stepContainer := newStepContainer(ctx, step, image, cmd, entrypoint)
	return common.NewPipelineExecutor(
		prepImage,
		stepContainer.Pull(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(ctx context.Context, step step, action *model.Action, cmd *[]string) {
	rc := step.getRunContext()
	stepModel := step.getStepModel()

	inputs := make(map[string]string)
	eval := rc.NewExpressionEvaluator(ctx)
	// Set Defaults
	for k, input := range action.Inputs {
		inputs[k] = eval.Interpolate(ctx, input.Default)
	}
	if stepModel.With != nil {
		for k, v := range stepModel.With {
			inputs[k] = eval.Interpolate(ctx, v)
		}
	}
	mergeIntoMap(step, step.getEnv(), inputs)

	stepEE := rc.NewStepExpressionEvaluator(ctx, step)
	for i, v := range *cmd {
		(*cmd)[i] = stepEE.Interpolate(ctx, v)
	}
	mergeIntoMap(step, step.getEnv(), action.Runs.Env)

	ee := rc.NewStepExpressionEvaluator(ctx, step)
	for k, v := range *step.getEnv() {
		(*step.getEnv())[k] = ee.Interpolate(ctx, 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_ARCH", container.RunnerArch(ctx)))
	envList = append(envList, fmt.Sprintf("%s=%s", "RUNNER_TEMP", "/tmp"))

	binds, mounts := rc.GetBindsAndMounts()
	networkMode := fmt.Sprintf("container:%s", rc.jobContainerName())
	var workdir string
	if rc.IsHostEnv(ctx) {
		networkMode = "default"
		ext := container.LinuxContainerEnvironmentExtensions{}
		workdir = ext.ToContainerPath(rc.Config.Workdir)
	} else {
		workdir = rc.JobContainer.ToContainerPath(rc.Config.Workdir)
	}
	stepContainer := container.NewContainer(&container.NewContainerInput{
		Cmd:         cmd,
		Entrypoint:  entrypoint,
		WorkingDir:  workdir,
		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: networkMode,
		Binds:       binds,
		Stdout:      logWriter,
		Stderr:      logWriter,
		Privileged:  rc.Config.Privileged,
		UsernsMode:  rc.Config.UsernsMode,
		Platform:    rc.Config.ContainerArchitecture,
		Options:     rc.Config.ContainerOptions,
	})
	return stepContainer
}

func populateEnvsFromSavedState(env *map[string]string, step actionStep, rc *RunContext) {
	state, ok := rc.IntraActionState[step.getStepModel().ID]
	if ok {
		for name, value := range state {
			envName := fmt.Sprintf("STATE_%s", name)
			(*env)[envName] = value
		}
	}
}

func populateEnvsFromInput(ctx context.Context, env *map[string]string, action *model.Action, rc *RunContext) {
	eval := rc.NewExpressionEvaluator(ctx)
	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(ctx, input.Default)
		}
	}
}

func normalizePath(s string) string {
	if runtime.GOOS == "windows" {
		return strings.ReplaceAll(s, "\\", "/")
	}
	return s
}

func getOsSafeRelativePath(s, prefix string) string {
	actionName := strings.TrimPrefix(s, prefix)
	actionName = normalizePath(actionName)
	actionName = strings.TrimPrefix(actionName, "/")

	return actionName
}

func shouldRunPreStep(step actionStep) common.Conditional {
	return func(ctx context.Context) bool {
		log := common.Logger(ctx)

		if step.getActionModel() == nil {
			log.Debugf("skip pre step for '%s': no action model available", step.getStepModel())
			return false
		}

		return true
	}
}

func hasPreStep(step actionStep) common.Conditional {
	return func(_ context.Context) bool {
		action := step.getActionModel()
		return action.Runs.Using.IsComposite() ||
			(action.Runs.Using.IsNode() &&
				action.Runs.Pre != "") ||
			(action.Runs.Using.IsDocker() &&
				action.Runs.PreEntrypoint != "")
	}
}

func runPreStep(step actionStep) common.Executor {
	return func(ctx context.Context) error {
		logger := common.Logger(ctx)
		logger.Debugf("run pre step for '%s'", step.getStepModel())

		rc := step.getRunContext()
		action := step.getActionModel()

		// defaults in pre steps were missing, however provided inputs are available
		populateEnvsFromInput(ctx, step.getEnv(), action, rc)

		actionPath := step.getActionPath()

		actionName, containerActionDir := step.getContainerActionPaths()

		x := action.Runs.Using
		switch {
		case x.IsNode():
			if err := step.maybeCopyToActionDir(ctx); err != nil {
				return err
			}

			containerArgs := []string{rc.GetNodeToolFullPath(ctx), path.Join(containerActionDir, action.Runs.Pre)}
			logger.Debugf("executing remote job container: %s", containerArgs)

			rc.ApplyExtraPath(ctx, step.getEnv())

			return rc.execJobContainer(containerArgs, *step.getEnv(), "", "")(ctx)

		case x.IsDocker():
			return execAsDocker(ctx, step, actionName, actionPath, "pre-entrypoint")

		case x.IsComposite():
			if step.getCompositeSteps() == nil {
				step.getCompositeRunContext(ctx)
			}

			if steps := step.getCompositeSteps(); steps != nil && steps.pre != nil {
				return steps.pre(ctx)
			}
			return fmt.Errorf("missing steps in composite action")

		default:
			return nil
		}
	}
}

func shouldRunPostStep(step actionStep) common.Conditional {
	return func(ctx context.Context) bool {
		log := common.Logger(ctx)
		stepResults := step.getRunContext().getStepsContext()
		stepResult := stepResults[step.getStepModel().ID]

		if stepResult == nil {
			log.WithField("stepResult", model.StepStatusSkipped).Debugf("skipping post step for '%s'; step was not executed", step.getStepModel())
			return false
		}

		if stepResult.Conclusion == model.StepStatusSkipped {
			log.WithField("stepResult", model.StepStatusSkipped).Debugf("skipping post step for '%s'; main step was skipped", step.getStepModel())
			return false
		}

		if step.getActionModel() == nil {
			log.WithField("stepResult", model.StepStatusSkipped).Debugf("skipping post step for '%s': no action model available", step.getStepModel())
			return false
		}

		return true
	}
}

func hasPostStep(step actionStep) common.Conditional {
	return func(_ context.Context) bool {
		action := step.getActionModel()
		return action.Runs.Using.IsComposite() ||
			(action.Runs.Using.IsNode() &&
				action.Runs.Post != "") ||
			(action.Runs.Using.IsDocker() &&
				action.Runs.PostEntrypoint != "")
	}
}

func runPostStep(step actionStep) common.Executor {
	return func(ctx context.Context) error {
		logger := common.Logger(ctx)
		logger.Debugf("run post step for '%s'", step.getStepModel())

		rc := step.getRunContext()
		action := step.getActionModel()

		actionPath := step.getActionPath()

		actionName, containerActionDir := step.getContainerActionPaths()

		x := action.Runs.Using
		switch {
		case x.IsNode():
			if err := step.maybeCopyToActionDir(ctx); err != nil {
				return err
			}
			populateEnvsFromSavedState(step.getEnv(), step, rc)
			populateEnvsFromInput(ctx, step.getEnv(), step.getActionModel(), rc)

			containerArgs := []string{rc.GetNodeToolFullPath(ctx), path.Join(containerActionDir, action.Runs.Post)}
			logger.Debugf("executing remote job container: %s", containerArgs)

			rc.ApplyExtraPath(ctx, step.getEnv())

			return rc.execJobContainer(containerArgs, *step.getEnv(), "", "")(ctx)

		case x.IsDocker():
			return execAsDocker(ctx, step, actionName, actionPath, "post-entrypoint")

		case x.IsComposite():
			if err := step.maybeCopyToActionDir(ctx); err != nil {
				return err
			}

			if steps := step.getCompositeSteps(); steps != nil && steps.post != nil {
				return steps.post(ctx)
			}
			return fmt.Errorf("missing steps in composite action")

		default:
			return nil
		}
	}
}