package runner

import (
	"context"
	"fmt"
	"io/ioutil"
	"path/filepath"
	"regexp"
	"runtime"
	"strings"
	"time"

	log "github.com/sirupsen/logrus"

	"github.com/nektos/act/pkg/common"
	"github.com/nektos/act/pkg/container"
	"github.com/nektos/act/pkg/exprparser"
	"github.com/nektos/act/pkg/model"
)

// Runner provides capabilities to run GitHub actions
type Runner interface {
	NewPlanExecutor(plan *model.Plan) common.Executor
}

// Config contains the config for a new runner
type Config struct {
	Actor                              string            // the user that triggered the event
	Workdir                            string            // path to working directory
	BindWorkdir                        bool              // bind the workdir to the job container
	EventName                          string            // name of event to run
	EventPath                          string            // path to JSON file to use for event.json in containers
	DefaultBranch                      string            // name of the main branch for this repository
	ReuseContainers                    bool              // reuse containers to maintain state
	ForcePull                          bool              // force pulling of the image, even if already present
	ForceRebuild                       bool              // force rebuilding local docker image action
	LogOutput                          bool              // log the output from docker run
	JSONLogger                         bool              // use json or text logger
	Env                                map[string]string // env for containers
	Secrets                            map[string]string // list of secrets
	Token                              string            // GitHub token
	InsecureSecrets                    bool              // switch hiding output when printing to terminal
	Platforms                          map[string]string // list of platforms
	Privileged                         bool              // use privileged mode
	UsernsMode                         string            // user namespace to use
	ContainerArchitecture              string            // Desired OS/architecture platform for running containers
	ContainerDaemonSocket              string            // Path to Docker daemon socket
	UseGitIgnore                       bool              // controls if paths in .gitignore should not be copied into container, default true
	GitHubInstance                     string            // GitHub instance to use, default "github.com"
	ContainerCapAdd                    []string          // list of kernel capabilities to add to the containers
	ContainerCapDrop                   []string          // list of kernel capabilities to remove from the containers
	AutoRemove                         bool              // controls if the container is automatically removed upon workflow completion
	ArtifactServerPath                 string            // the path where the artifact server stores uploads
	ArtifactServerPort                 string            // the port the artifact server binds to
	NoSkipCheckout                     bool              // do not skip actions/checkout
	RemoteName                         string            // remote name in local git repo config
	ReplaceGheActionWithGithubCom      []string          // Use actions from GitHub Enterprise instance to GitHub
	ReplaceGheActionTokenWithGithubCom string            // Token of private action repo on GitHub.
}

// Resolves the equivalent host path inside the container
// This is required for windows and WSL 2 to translate things like C:\Users\Myproject to /mnt/users/Myproject
// For use in docker volumes and binds
func (config *Config) containerPath(path string) string {
	if runtime.GOOS == "windows" && strings.Contains(path, "/") {
		log.Error("You cannot specify linux style local paths (/mnt/etc) on Windows as it does not understand them.")
		return ""
	}

	abspath, err := filepath.Abs(path)
	if err != nil {
		log.Error(err)
		return ""
	}

	// Test if the path is a windows path
	windowsPathRegex := regexp.MustCompile(`^([a-zA-Z]):\\(.+)$`)
	windowsPathComponents := windowsPathRegex.FindStringSubmatch(abspath)

	// Return as-is if no match
	if windowsPathComponents == nil {
		return abspath
	}

	// Convert to WSL2-compatible path if it is a windows path
	// NOTE: Cannot use filepath because it will use the wrong path separators assuming we want the path to be windows
	// based if running on Windows, and because we are feeding this to Docker, GoLang auto-path-translate doesn't work.
	driveLetter := strings.ToLower(windowsPathComponents[1])
	translatedPath := strings.ReplaceAll(windowsPathComponents[2], `\`, `/`)
	// Should make something like /mnt/c/Users/person/My Folder/MyActProject
	result := strings.Join([]string{"/mnt", driveLetter, translatedPath}, `/`)
	return result
}

// Resolves the equivalent host path inside the container
// This is required for windows and WSL 2 to translate things like C:\Users\Myproject to /mnt/users/Myproject
func (config *Config) ContainerWorkdir() string {
	return config.containerPath(config.Workdir)
}

type runnerImpl struct {
	config    *Config
	eventJSON string
}

// New Creates a new Runner
func New(runnerConfig *Config) (Runner, error) {
	runner := &runnerImpl{
		config: runnerConfig,
	}

	runner.eventJSON = "{}"
	if runnerConfig.EventPath != "" {
		log.Debugf("Reading event.json from %s", runner.config.EventPath)
		eventJSONBytes, err := ioutil.ReadFile(runner.config.EventPath)
		if err != nil {
			return nil, err
		}
		runner.eventJSON = string(eventJSONBytes)
	}
	return runner, nil
}

// NewPlanExecutor ...
//nolint:gocyclo
func (runner *runnerImpl) NewPlanExecutor(plan *model.Plan) common.Executor {
	maxJobNameLen := 0

	stagePipeline := make([]common.Executor, 0)
	for i := range plan.Stages {
		s := i
		stage := plan.Stages[i]
		stagePipeline = append(stagePipeline, func(ctx context.Context) error {
			pipeline := make([]common.Executor, 0)
			for r, run := range stage.Runs {
				stageExecutor := make([]common.Executor, 0)
				job := run.Job()

				if job.Uses != "" {
					return fmt.Errorf("reusable workflows are currently not supported (see https://github.com/nektos/act/issues/826 for updates)")
				}

				if job.Strategy != nil {
					strategyRc := runner.newRunContext(ctx, run, nil)
					if err := strategyRc.NewExpressionEvaluator(ctx).EvaluateYamlNode(ctx, &job.Strategy.RawMatrix); err != nil {
						log.Errorf("Error while evaluating matrix: %v", err)
					}
				}
				matrixes := job.GetMatrixes()
				maxParallel := 4
				if job.Strategy != nil {
					maxParallel = job.Strategy.MaxParallel
				}

				if len(matrixes) < maxParallel {
					maxParallel = len(matrixes)
				}

				for i, matrix := range matrixes {
					rc := runner.newRunContext(ctx, run, matrix)
					rc.JobName = rc.Name
					if len(matrixes) > 1 {
						rc.Name = fmt.Sprintf("%s-%d", rc.Name, i+1)
					}
					// evaluate environment variables since they can contain
					// GitHub's special environment variables.
					for k, v := range rc.GetEnv() {
						valueEval, err := rc.ExprEval.evaluate(ctx, v, exprparser.DefaultStatusCheckNone)
						if err == nil {
							rc.Env[k] = fmt.Sprintf("%v", valueEval)
						}
					}
					if len(rc.String()) > maxJobNameLen {
						maxJobNameLen = len(rc.String())
					}
					stageExecutor = append(stageExecutor, func(ctx context.Context) error {
						logger := common.Logger(ctx)
						jobName := fmt.Sprintf("%-*s", maxJobNameLen, rc.String())
						return rc.Executor().Finally(func(ctx context.Context) error {
							isLastRunningContainer := func(currentStage int, currentRun int) bool {
								return currentStage == len(plan.Stages)-1 && currentRun == len(stage.Runs)-1
							}

							if runner.config.AutoRemove && isLastRunningContainer(s, r) {
								var cancel context.CancelFunc
								if ctx.Err() == context.Canceled {
									ctx, cancel = context.WithTimeout(context.Background(), 5*time.Minute)
									defer cancel()
								}

								log.Infof("Cleaning up container for job %s", rc.JobName)

								if err := rc.stopJobContainer()(ctx); err != nil {
									logger.Errorf("Error while cleaning container: %v", err)
								}
							}

							return nil
						})(common.WithJobErrorContainer(WithJobLogger(ctx, rc.Run.JobID, jobName, rc.Config, &rc.Masks)))
					})
				}
				pipeline = append(pipeline, common.NewParallelExecutor(maxParallel, stageExecutor...))
			}
			var ncpu int
			info, err := container.GetHostInfo(ctx)
			if err != nil {
				log.Errorf("failed to obtain container engine info: %s", err)
				ncpu = 1 // sane default?
			} else {
				ncpu = info.NCPU
			}
			return common.NewParallelExecutor(ncpu, pipeline...)(ctx)
		})
	}

	return common.NewPipelineExecutor(stagePipeline...).Then(handleFailure(plan))
}

func handleFailure(plan *model.Plan) common.Executor {
	return func(ctx context.Context) error {
		for _, stage := range plan.Stages {
			for _, run := range stage.Runs {
				if run.Job().Result == "failure" {
					return fmt.Errorf("Job '%s' failed", run.String())
				}
			}
		}
		return nil
	}
}

func (runner *runnerImpl) newRunContext(ctx context.Context, run *model.Run, matrix map[string]interface{}) *RunContext {
	rc := &RunContext{
		Config:      runner.config,
		Run:         run,
		EventJSON:   runner.eventJSON,
		StepResults: make(map[string]*model.StepResult),
		Matrix:      matrix,
	}
	rc.ExprEval = rc.NewExpressionEvaluator(ctx)
	rc.Name = rc.ExprEval.Interpolate(ctx, run.String())
	return rc
}