package runner

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"
	"time"

	"bugabinga.net/luci/internal/artifact"
	"bugabinga.net/luci/internal/buildctx"
	"bugabinga.net/luci/internal/cache"
	"bugabinga.net/luci/internal/ciconfig"
	"bugabinga.net/luci/internal/config"
	"bugabinga.net/luci/internal/gitrepo"
	"bugabinga.net/luci/internal/history"
	"bugabinga.net/luci/internal/lifecycle"
	"bugabinga.net/luci/internal/logs"
	"bugabinga.net/luci/internal/podman"
	"bugabinga.net/luci/internal/publish"
	"bugabinga.net/luci/internal/runstate"
	"bugabinga.net/luci/internal/trigger"
)

type Runner struct {
	Config    config.Config
	Executor  podman.Executor
	Publisher publish.Executor
	Now       func() time.Time
}

var defaultExecutor = func(socket string) podman.Executor { return podman.CLI{Socket: socket} }
var defaultPublisher = func(cfg config.Config) publish.Executor {
	return publish.Service{
		RegistryAuthFile: cfg.PublishRegistryAuthFile,
		PkgRoot:          cfg.PublishPkgRoot,
		SiteRoot:         cfg.PublishSiteRoot,
	}
}

type plan struct {
	repo        string
	parentJob   string
	repoPath    string
	rev         string
	ref         string
	trigger     string
	subject     string
	children    []ciconfig.ExpandedJob
	buildImages map[string]string
	buildTags   map[string]bool
}

type childResult struct {
	status string
	detail string
}

func (r Runner) Process(runID string, event trigger.Event) error {
	return r.ProcessContext(context.Background(), runID, event)
}

// ProcessContext permits cancellation while waiting for durable job mounts.
func (r Runner) ProcessContext(ctx context.Context, runID string, event trigger.Event) error {
	lock, err := lifecycle.TryLockRun(r.Config.DataDir, runID, true)
	if err != nil {
		return err
	}
	defer lock.Close()
	deleted, err := lifecycle.Deleted(r.Config.DataDir, runID)
	if err != nil {
		return err
	}
	if deleted {
		return nil
	}
	completed, err := r.history().Contains(runID, "run")
	if err != nil {
		return err
	}
	if completed {
		return nil
	}
	switch event.(type) {
	case trigger.ManualEvent, trigger.PushEvent, trigger.ScheduleEvent:
	default:
		return fmt.Errorf("unsupported event %T", event)
	}
	started := r.now()
	p, err := r.makePlan(event, runID)
	defer os.RemoveAll(filepath.Join(r.Config.DataDir, "workspaces", p.repo, runID))
	if err != nil {
		if p.parentJob == "" {
			p = eventPlan(event)
		}
		_, appendErr := r.history().AppendOnce(history.Event{RunID: runID, ChildID: "run", Repo: p.repo, Job: p.parentJob, Rev: p.rev, Ref: p.ref, Trigger: p.trigger, Status: "failed", Subject: p.subject, Detail: err.Error(), StartedAt: started, Time: r.now()})
		return appendErr
	}
	p.buildImages = make(map[string]string)
	p.buildTags = make(map[string]bool)
	defer r.finishBuiltImages(p.buildTags)
	failed := false
	for i, child := range p.children {
		childID := fmt.Sprintf("%03d", i+1)
		if failed {
			_, err := r.history().AppendOnce(history.Event{RunID: runID, ChildID: childID, Repo: p.repo, Job: child.Name, Rev: p.rev, Ref: p.ref, Trigger: p.trigger, Status: "skipped", Detail: "skipped after earlier failure", Matrix: child.Values, Time: r.now()})
			if err != nil {
				return err
			}
			continue
		}
		result, err := r.runExpandedContext(ctx, runID, childID, p, child)
		if err != nil {
			return err
		}
		failed = result.status == "failed"
	}
	status := "success"
	if failed {
		status = "failed"
	}
	_, err = r.history().AppendOnce(history.Event{RunID: runID, ChildID: "run", Repo: p.repo, Job: p.parentJob, Rev: p.rev, Ref: p.ref, Trigger: p.trigger, Status: status, Subject: p.subject, StartedAt: started, Time: r.now()})
	return err
}

func (r Runner) makePlan(event trigger.Event, runID string) (plan, error) {
	switch event := event.(type) {
	case trigger.ManualEvent:
		return r.manualPlan(event, runID)
	case trigger.PushEvent:
		return r.pushPlan(event, runID)
	case trigger.ScheduleEvent:
		return r.schedulePlan(event, runID)
	default:
		return plan{}, fmt.Errorf("unsupported event %T", event)
	}
}

// AdmitManual resolves a manual request and validates its selected job before it enters the inbox.
func AdmitManual(cfg config.Config, event trigger.ManualEvent) (trigger.ManualEvent, error) {
	if err := event.Validate(); err != nil {
		return trigger.ManualEvent{}, err
	}
	repoPath, err := gitrepo.RepoPath(cfg.RepoRoots, event.Repo)
	if err != nil {
		return trigger.ManualEvent{}, err
	}
	ref, rev := "", ""
	if event.Ref != nil {
		ref = *event.Ref
	}
	if event.Rev != nil {
		rev = *event.Rev
	}
	resolved, err := gitrepo.Resolve(repoPath, ref, rev)
	if err != nil {
		return trigger.ManualEvent{}, err
	}
	files, err := gitrepo.FilesAtRev(repoPath, resolved, ".ci")
	if err != nil {
		return trigger.ManualEvent{}, err
	}
	for path := range files {
		if !strings.HasSuffix(path, ".kdl") {
			delete(files, path)
		}
	}
	repository, err := ciconfig.ParseFiles(files)
	if err != nil {
		return trigger.ManualEvent{}, err
	}
	if _, ok := repository.Job(event.Job); !ok {
		return trigger.ManualEvent{}, fmt.Errorf("job %q not found", event.Job)
	}
	event.ResolvedRev = resolved
	return event, nil
}

func (r Runner) manualPlan(event trigger.ManualEvent, runID string) (plan, error) {
	p := eventPlan(event)
	if p.rev == "" {
		return p, fmt.Errorf("manual event was not admitted; resubmit the run")
	}
	repoPath, err := gitrepo.RepoPath(r.Config.RepoRoots, event.Repo)
	if err != nil {
		return p, err
	}
	p.repoPath = repoPath
	p.subject = gitrepo.Subject(repoPath, p.rev)
	cfg, _, err := r.loadRepoConfig(repoPath, p.rev, event.Repo, runID)
	if err != nil {
		return p, err
	}
	job, ok := cfg.Job(event.Job)
	if !ok {
		return p, fmt.Errorf("job %q not found", event.Job)
	}
	p.children = job.ExpandMatrix()
	return p, nil
}

func (r Runner) schedulePlan(event trigger.ScheduleEvent, runID string) (plan, error) {
	p := eventPlan(event)
	repoPath, err := gitrepo.RepoPath(r.Config.RepoRoots, event.Repo)
	if err != nil {
		return p, err
	}
	resolved, err := gitrepo.Resolve(repoPath, "", event.Rev)
	if err != nil {
		return p, err
	}
	p.repoPath, p.rev = repoPath, resolved
	p.subject = gitrepo.Subject(repoPath, resolved)
	cfg, _, err := r.loadRepoConfig(repoPath, resolved, event.Repo, runID)
	if err != nil {
		return p, err
	}
	job, ok := cfg.Job(event.Job)
	if !ok {
		return p, fmt.Errorf("job %q not found", event.Job)
	}
	p.children = job.ExpandMatrix()
	return p, nil
}

func (r Runner) pushPlan(event trigger.PushEvent, runID string) (plan, error) {
	p := eventPlan(event)
	requestedRev := p.rev
	p.rev = ""
	repoPath, err := gitrepo.RepoPath(r.Config.RepoRoots, event.Repo)
	if err != nil {
		return p, err
	}
	resolved, err := gitrepo.Resolve(repoPath, "", requestedRev)
	if err != nil {
		p.rev = ""
		return p, err
	}
	p.repoPath, p.rev = repoPath, resolved
	p.subject = gitrepo.Subject(repoPath, resolved)
	cfg, _, err := r.loadRepoConfig(repoPath, resolved, event.Repo, runID)
	if err != nil {
		return p, err
	}
	var changedPaths []string
	for _, job := range cfg.Jobs {
		if job.NeedsChangedPaths() {
			changedPaths, err = gitrepo.ChangedPaths(repoPath, event.Old, resolved)
			if err != nil {
				return p, err
			}
			break
		}
	}
	for _, job := range cfg.Jobs {
		if job.MatchesPush(event.Ref, changedPaths) {
			p.children = append(p.children, job.ExpandMatrix()...)
		}
	}
	return p, nil
}

func eventPlan(event trigger.Event) plan {
	switch event := event.(type) {
	case trigger.ManualEvent:
		p := plan{repo: event.Repo, parentJob: event.Job, rev: event.ResolvedRev, trigger: "manual"}
		if event.Ref != nil {
			p.ref = *event.Ref
		}
		return p
	case trigger.PushEvent:
		return plan{repo: event.Repo, parentJob: "push", rev: event.New, ref: event.Ref, trigger: "push"}
	case trigger.ScheduleEvent:
		return plan{repo: event.Repo, parentJob: event.Job, rev: event.Rev, ref: event.Ref, trigger: "schedule"}
	default:
		return plan{parentJob: "run", trigger: "unknown"}
	}
}

func (r Runner) loadRepoConfig(repoPath, rev, repo, runID string) (ciconfig.Config, string, error) {
	workspace := filepath.Join(r.Config.DataDir, "workspaces", repo, runID, "config")
	if err := gitrepo.Checkout(repoPath, rev, workspace); err != nil {
		return ciconfig.Config{}, "", err
	}
	cfg, err := ciconfig.Load(workspace)
	return cfg, workspace, err
}

func (r Runner) runExpanded(runID, childID string, p plan, expanded ciconfig.ExpandedJob) (childResult, error) {
	return r.runExpandedContext(context.Background(), runID, childID, p, expanded)
}

func (r Runner) runExpandedContext(ctx context.Context, runID, childID string, p plan, expanded ciconfig.ExpandedJob) (childResult, error) {
	started := r.now()
	activeStore := runstate.Store{DataDir: r.Config.DataDir}
	if err := activeStore.Write(runstate.Active{RunID: runID, ChildID: childID, Repo: p.repo, Job: expanded.Name, Rev: p.rev, Ref: p.ref, Trigger: p.trigger, StartedAt: started}); err != nil {
		return childResult{}, err
	}
	logName := runID + "-" + childID
	logStore := logs.Store{DataDir: r.Config.DataDir}
	logFile, err := logStore.CreateLive(logName)
	if err != nil {
		return childResult{}, err
	}

	workspace := filepath.Join(r.Config.DataDir, "workspaces", p.repo, runID, childID)
	var logWriter *logs.Sanitizer
	var logErr error
	runErr := gitrepo.Checkout(p.repoPath, p.rev, workspace)
	if runErr == nil {
		runErr = registryOutputsAbsent(workspace, expanded)
	}
	image := ciconfig.Interpolate(expanded.Job.Image, expanded.Values)
	runCtx, cancel := context.WithTimeout(ctx, r.Config.DefaultTimeout)
	defer cancel()
	if runErr == nil && expanded.Job.Build != nil {
		logWriter = logs.NewBoundedSanitizer(logFile, nil)
		image, runErr = r.buildImage(runCtx, p, expanded, workspace, runID, childID, logWriter)
	}
	if runErr == nil {
		var secretValues [][]byte
		var secretMounts []podman.Mount
		var envFile string
		var removeSecrets func()
		secretMounts, envFile, secretValues, removeSecrets, runErr = r.materializeSecrets(p.repo, expanded.Job, runID, childID)
		defer removeSecrets()
		logWriter = logs.NewBoundedSanitizer(logFile, secretValues)
		if runErr == nil {
			env, envErr := frozenEnvironment(runID, childID, p, expanded, nil)
			if envErr != nil {
				runErr = envErr
			}
			resolvedCaches := make([]ciconfig.Cache, len(expanded.Job.Caches))
			cacheKeys := make([]string, len(expanded.Job.Caches))
			cacheStore := cache.Store{DataDir: r.Config.DataDir, MaxVersions: r.Config.CacheMaxVersions, MaxBytes: r.Config.CacheMaxBytes}
			for i, entry := range expanded.Job.Caches {
				if runErr != nil {
					break
				}
				entry.Path = ciconfig.Interpolate(entry.Path, expanded.Values)
				entry.KeyFiles = append([]string(nil), entry.KeyFiles...)
				for j := range entry.KeyFiles {
					entry.KeyFiles[j] = ciconfig.Interpolate(entry.KeyFiles[j], expanded.Values)
				}
				resolvedCaches[i] = entry
				cacheKeys[i], runErr = cache.Key(workspace, entry)
				if runErr == nil {
					var outcome string
					outcome, runErr = cacheStore.Restore(p.repo, expanded.Job.Name, entry, cacheKeys[i], workspace)
					if runErr == nil {
						_, runErr = fmt.Fprintf(logWriter, "[luci] cache %s: %s\n", entry.Name, outcome)
						if runErr != nil {
							logErr = errors.Join(logErr, runErr)
						}
					}
				}
				if runErr != nil {
					break
				}
			}
			if runErr == nil {
				commands := make([]string, 0, len(expanded.Job.Run))
				for _, command := range expanded.Job.Run {
					commands = append(commands, ciconfig.Interpolate(command, expanded.Values))
				}
				if r.Executor == nil {
					r.Executor = defaultExecutor(r.Config.PodmanSocket)
				}
				mounts, releaseMounts, mountErr := durableMounts(runCtx, r.Config.DataDir, p.repo, expanded.Job.Name, expanded.Job.Mounts)
				if mountErr != nil {
					runErr = mountErr
				} else {
					defer releaseMounts()
					spec := podman.Spec{Image: image, Pull: pullPolicy(expanded.Job), Workspace: workspace, Memory: r.Config.DefaultMemory, CPUs: r.Config.DefaultCPUs, Env: env, EnvFile: envFile, Mounts: append(mounts, secretMounts...), Commands: commands, Timeout: r.Config.DefaultTimeout}
					args := podman.BuildArgs(spec)
					if executor, ok := r.Executor.(podman.EnvironmentExecutor); ok {
						runErr = executor.RunWithEnv(runCtx, args, podman.Environment(spec), logWriter, logWriter)
					} else {
						runErr = r.Executor.Run(runCtx, args, logWriter, logWriter)
					}
				}
			}
			if runErr == nil {
				for i, entry := range resolvedCaches {
					if runErr = cacheStore.Save(p.repo, expanded.Job.Name, entry, cacheKeys[i], workspace); runErr != nil {
						break
					}
				}
			}
			if runErr == nil && len(expanded.Job.Publishes) > 0 {
				if r.Publisher == nil {
					r.Publisher = defaultPublisher(r.Config)
				}
				values := make(map[string]string, len(expanded.Values)+1)
				for key, value := range expanded.Values {
					values[key] = value
				}
				values["rev"] = p.rev
				for _, declaration := range expanded.Job.Publishes {
					runErr = r.Publisher.Publish(runCtx, publish.Request{Adapter: declaration.Adapter, Image: ciconfig.Interpolate(declaration.Image, values), From: ciconfig.Interpolate(declaration.From, values), To: ciconfig.Interpolate(declaration.To, values), Workspace: workspace}, logWriter)
					if runErr != nil {
						break
					}
				}
			}
			artifactStore := artifact.Store{DataDir: r.Config.DataDir}
			for _, declaration := range expanded.Job.Artifacts {
				if runErr != nil && !declaration.AfterFailure {
					continue
				}
				if err := artifactStore.Collect(workspace, runID, childID, declaration); err != nil {
					runErr = errors.Join(runErr, err)
				}
			}
		}
	}
	if logWriter == nil {
		logWriter = logs.NewBoundedSanitizer(logFile, nil)
	}
	if runErr != nil {
		if _, err := fmt.Fprintln(logWriter, runErr); err != nil {
			logErr = errors.Join(logErr, err)
		}
	}
	if err := logWriter.Close(); err != nil {
		logErr = errors.Join(logErr, err)
	}
	if err := logFile.Close(); err != nil {
		logErr = errors.Join(logErr, err)
	}
	if _, err := logStore.Finalize(logName); err != nil {
		return childResult{}, errors.Join(logErr, err)
	}
	if logErr != nil {
		return childResult{}, logErr
	}
	result := childResult{status: "success"}
	if runErr != nil {
		result.status, result.detail = "failed", runErr.Error()
	}
	_, err = r.history().AppendOnce(history.Event{RunID: runID, ChildID: childID, Repo: p.repo, Job: expanded.Name, Rev: p.rev, Ref: p.ref, Trigger: p.trigger, Status: result.status, Subject: p.subject, Detail: result.detail, Matrix: expanded.Values, StartedAt: started, Time: r.now()})
	if err != nil {
		return childResult{}, err
	}
	if err := activeStore.Remove(runID); err != nil {
		return childResult{}, err
	}
	return result, nil
}

func registryOutputsAbsent(workspace string, expanded ciconfig.ExpandedJob) error {
	for _, declaration := range expanded.Job.Publishes {
		if declaration.Adapter != "registry" {
			continue
		}
		from := ciconfig.Interpolate(declaration.From, expanded.Values)
		clean := filepath.Clean(from)
		if strings.TrimSpace(from) == "" || filepath.IsAbs(from) || clean == "." || clean == ".." || strings.HasPrefix(clean, ".."+string(filepath.Separator)) {
			return fmt.Errorf("publish registry has unsafe from path %q", from)
		}
		for _, cache := range expanded.Job.Caches {
			path := ciconfig.Interpolate(cache.Path, expanded.Values)
			if pathsOverlap(clean, filepath.Clean(path)) {
				return fmt.Errorf("publish registry from %q conflicts with cache path %q", from, path)
			}
		}
		for _, artifact := range expanded.Job.Artifacts {
			for _, path := range artifact.Paths {
				if pathsOverlap(clean, filepath.Clean(path)) {
					return fmt.Errorf("publish registry from %q conflicts with artifact path %q", from, path)
				}
			}
		}
		if _, err := os.Lstat(filepath.Join(workspace, clean)); err == nil {
			return fmt.Errorf("publish registry output %q already exists before commands", from)
		} else if !os.IsNotExist(err) {
			return err
		}
	}
	return nil
}

func pathsOverlap(left, right string) bool {
	return left == right || strings.HasPrefix(left, right+string(filepath.Separator)) || strings.HasPrefix(right, left+string(filepath.Separator))
}

func (r *Runner) buildImage(ctx context.Context, p plan, expanded ciconfig.ExpandedJob, workspace, runID, childID string, output io.Writer) (string, error) {
	if err := ctx.Err(); err != nil {
		return "", err
	}
	build := *expanded.Job.Build
	build.Containerfile = ciconfig.Interpolate(build.Containerfile, expanded.Values)
	build.Context = ciconfig.Interpolate(build.Context, expanded.Values)
	key := p.rev + "\x00" + build.Containerfile + "\x00" + build.Context
	if image := p.buildImages[key]; image != "" {
		fmt.Fprintf(output, "[luci] build reused image=%s\n", image)
		return image, nil
	}
	if err := r.prepareBuildStorage(p, output); err != nil {
		return "", err
	}
	root := filepath.Join(r.Config.DataDir, "build-context")
	if err := os.MkdirAll(root, 0o700); err != nil {
		return "", err
	}
	stage, err := os.MkdirTemp(root, "build-")
	if err != nil {
		return "", err
	}
	defer os.RemoveAll(stage)
	containerfile, contextDir, err := buildctx.Stage(workspace, build.Containerfile, build.Context, stage, r.Config.BuildContextMaxBytes, r.Config.BuildContextMaxFiles)
	if err != nil {
		return "", err
	}
	if err := safeContainerfile(containerfile); err != nil {
		return "", err
	}
	iid := filepath.Join(stage, "iid")
	authFile := filepath.Join(stage, "auth.json")
	if err := os.WriteFile(authFile, []byte(`{"auths":{}}`), 0o600); err != nil {
		return "", err
	}
	tag := "luci-build-" + runID + "-" + childID
	args, err := podman.BuildArgsForContainerfile(podman.BuildSpec{Containerfile: containerfile, Context: contextDir, Tag: tag, IIDFile: iid, AuthFile: authFile, Memory: r.Config.DefaultMemory, CPUs: r.Config.DefaultCPUs})
	if err != nil {
		return "", err
	}
	if p.buildTags == nil {
		p.buildTags = make(map[string]bool)
	}
	p.buildTags[tag] = true
	fmt.Fprintf(output, "[luci] build start containerfile=%s context=%s\n", build.Containerfile, build.Context)
	buildStarted := time.Now()
	executor := r.executor()
	if environmentExecutor, ok := executor.(podman.EnvironmentExecutor); ok {
		err = environmentExecutor.RunWithEnv(ctx, args, nil, output, output)
	} else {
		err = executor.Run(ctx, args, output, output)
	}
	if err != nil {
		return "", fmt.Errorf("build %s failed after %s: %w", build.Containerfile, time.Since(buildStarted).Round(time.Second), err)
	}
	data, err := os.ReadFile(iid)
	if err != nil {
		return "", fmt.Errorf("build did not write image ID: %w", err)
	}
	image := strings.TrimSpace(string(data))
	if !immutableImageID(image) {
		return "", fmt.Errorf("build returned invalid image ID %q", image)
	}
	if err := r.verifyLuciBuildImage(image); err != nil {
		return "", err
	}
	p.buildImages[key] = image
	fmt.Fprintf(output, "[luci] build done image=%s in %s\n", image, time.Since(buildStarted).Round(time.Second))
	return image, nil
}

func (r *Runner) executor() podman.Executor {
	if r.Executor == nil {
		r.Executor = defaultExecutor(r.Config.PodmanSocket)
	}
	return r.Executor
}

func (r *Runner) finishBuiltImages(tags map[string]bool) {
	if len(tags) == 0 {
		return
	}
	ctx, cancel := context.WithTimeout(context.Background(), r.Config.BuildCleanupTimeout)
	defer cancel()
	executor := r.executor()
	for tag := range tags {
		// A tag, unlike an image ID, removes only this run's unique reference.
		// Podman receives no --force, so it preserves any active container.
		_ = executor.Run(ctx, podman.RemoveImageArgs(tag), io.Discard, io.Discard)
	}
	_, _ = podman.PruneLuciBuildCache(ctx, executor, r.Config.BuildCacheMaxBytes, r.Config.BuildCacheMaxAge, nil, r.now())
}

func (r *Runner) prepareBuildStorage(p plan, output io.Writer) error {
	ctx, cancel := context.WithTimeout(context.Background(), r.Config.BuildCleanupTimeout)
	defer cancel()
	protected := make(map[string]bool, len(p.buildImages))
	for _, image := range p.buildImages {
		protected[image] = true
	}
	report, err := podman.PruneLuciBuildCache(ctx, r.executor(), r.Config.BuildCacheMaxBytes, r.Config.BuildCacheMaxAge, protected, r.now())
	if err != nil {
		return fmt.Errorf("build cache retention: %w", err)
	}
	info, err := podman.StorageInfoFor(ctx, r.executor())
	if err != nil {
		return fmt.Errorf("build storage preflight: %w", err)
	}
	if info.Free() < r.Config.BuildMinFreeBytes {
		return fmt.Errorf("build requires %d free bytes on Podman graphroot; engine reports %d free of %d; free Podman storage or raise LUCI_BUILD_MIN_FREE_BYTES", r.Config.BuildMinFreeBytes, info.Free(), info.Allocated)
	}
	_, _ = fmt.Fprintf(output, "[luci] build cache bytes=%d removed=%d graphroot-free=%d\n", report.Bytes, len(report.Removed), info.Free())
	return nil
}

func (r *Runner) verifyLuciBuildImage(id string) error {
	ctx, cancel := context.WithTimeout(context.Background(), r.Config.BuildCleanupTimeout)
	defer cancel()
	images, err := podman.LuciBuildImages(ctx, r.executor())
	if err != nil {
		return fmt.Errorf("verify Luci build label: %w", err)
	}
	for _, image := range images {
		if sameImageID(image.ID, id) {
			return nil
		}
	}
	return fmt.Errorf("build output %s lacks required %s label; Containerfile must not override it", id, podman.BuildCacheLabel)
}

func sameImageID(left, right string) bool {
	return strings.TrimPrefix(left, "sha256:") == strings.TrimPrefix(right, "sha256:")
}

func pullPolicy(job ciconfig.Job) string {
	if job.Build != nil {
		return "never"
	}
	return ""
}

func immutableImageID(value string) bool {
	if !strings.HasPrefix(value, "sha256:") || len(value) != len("sha256:")+64 {
		return false
	}
	for _, char := range value[len("sha256:"):] {
		if !strings.ContainsRune("0123456789abcdef", char) {
			return false
		}
	}
	return true
}

// safeContainerfile rejects only RUN options that alter Buildah's execution
// boundary. It deliberately accepts ordinary shell text, comments, package
// installation, and every other normal Containerfile instruction.
func safeContainerfile(path string) error {
	data, err := os.ReadFile(path)
	if err != nil {
		return err
	}
	lines := strings.Split(string(data), "\n")
	escape := byte('\\')
	for _, line := range lines {
		trimmed := strings.TrimSpace(line)
		if strings.HasPrefix(strings.ToLower(trimmed), "# escape=") {
			value := strings.TrimSpace(trimmed[len("# escape="):])
			if len(value) == 1 && (value[0] == '\\' || value[0] == '`') {
				escape = value[0]
			}
			break
		}
		if trimmed != "" && !strings.HasPrefix(trimmed, "#") {
			break
		}
	}
	for lineNo := 0; lineNo < len(lines); lineNo++ {
		line := strings.TrimSpace(lines[lineNo])
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		logical := line
		for continued(logical, escape) && lineNo+1 < len(lines) {
			// Containerfile continuation removes the escape and newline. Preserve
			// the author-supplied space before the escape, but do not add one:
			// --net\ followed by work=host is still --network=host.
			logical = strings.TrimSuffix(strings.TrimRight(logical, " \t"), string(escape)) + strings.TrimLeft(lines[lineNo+1], " \t")
			lineNo++
		}
		instructionEnd := strings.IndexAny(logical, " \t")
		if instructionEnd < 0 || !strings.EqualFold(logical[:instructionEnd], "RUN") {
			continue
		}
		body := logical[instructionEnd:]
		for {
			body = strings.TrimLeft(body, " \t")
			if !strings.HasPrefix(body, "--") {
				break
			}
			optionEnd := strings.IndexAny(body, " \t")
			option, rest, found := body, "", optionEnd >= 0
			if found {
				option, rest = body[:optionEnd], body[optionEnd:]
			}
			name, _, _ := strings.Cut(strings.TrimPrefix(option, "--"), "=")
			switch strings.ToLower(name) {
			case "mount", "network", "security", "device":
				return fmt.Errorf("containerfile line %d uses unsupported RUN --%s extension", lineNo+1, name)
			}
			if !found {
				break
			}
			body = rest
		}
	}
	return nil
}

func continued(line string, escape byte) bool {
	trimmed := strings.TrimRight(line, " \t")
	count := 0
	for i := len(trimmed) - 1; i >= 0 && trimmed[i] == escape; i-- {
		count++
	}
	return count%2 == 1
}

func (r Runner) history() history.Store { return history.Store{DataDir: r.Config.DataDir, Now: r.Now} }
func (r Runner) now() time.Time {
	if r.Now != nil {
		return r.Now()
	}
	return time.Now()
}

func frozenEnvironment(runID, childID string, p plan, expanded ciconfig.ExpandedJob, secrets map[string]string) (map[string]string, error) {
	env := map[string]string{
		"CI_RUN_ID":   runID,
		"CI_CHILD_ID": childID,
		"CI_REPO":     p.repo,
		"CI_JOB":      expanded.Name,
		"CI_REV":      p.rev,
		"CI_REF":      p.ref,
		"CI_TRIGGER":  p.trigger,
	}
	for key, value := range expanded.Values {
		name := "CI_MATRIX_" + strings.ToUpper(key)
		if _, exists := env[name]; exists {
			return nil, fmt.Errorf("matrix env collision %q", name)
		}
		env[name] = value
	}
	for name, value := range secrets {
		if _, exists := env[name]; exists {
			return nil, fmt.Errorf("secret env %q collides with CI metadata", name)
		}
		env[name] = value
	}
	return env, nil
}

func (r Runner) materializeSecrets(repo string, job ciconfig.Job, runID, childID string) ([]podman.Mount, string, [][]byte, func(), error) {
	paths, err := job.SecretPaths(r.Config.DataDir, repo)
	if err != nil {
		return nil, "", nil, func() {}, err
	}
	tmpRoot := filepath.Join(r.Config.DataDir, "tmp")
	if err := os.MkdirAll(tmpRoot, 0o700); err != nil {
		return nil, "", nil, func() {}, err
	}
	dir, err := os.MkdirTemp(tmpRoot, "secrets-"+runID+"-"+childID+"-")
	if err != nil {
		return nil, "", nil, func() {}, err
	}
	cleanup := func() { _ = os.RemoveAll(dir) }
	var mounts []podman.Mount
	var values [][]byte
	var envLines []string
	for _, secret := range job.Secrets {
		data, err := os.ReadFile(paths[secret.Name])
		if err != nil {
			cleanup()
			return nil, "", nil, func() {}, fmt.Errorf("missing secret %s", secret.Name)
		}
		if len(data) > 0 {
			values = append(values, data)
		}
		if secret.Env != "" {
			value := strings.TrimRight(string(data), "\r\n")
			if strings.ContainsAny(value, "\r\n") {
				cleanup()
				return nil, "", nil, func() {}, fmt.Errorf("secret %s cannot be an environment value containing a newline", secret.Name)
			}
			envLines = append(envLines, secret.Env+"="+value)
		}
		if secret.File != "" {
			file := filepath.Join(dir, secret.Name)
			if err := os.WriteFile(file, data, 0o600); err != nil {
				cleanup()
				return nil, "", nil, func() {}, err
			}
			mounts = append(mounts, podman.Mount{Source: file, Target: "/work/" + filepath.ToSlash(secret.File), ReadOnly: true})
		}
	}
	envFile := ""
	if len(envLines) > 0 {
		envFile = filepath.Join(dir, "env")
		if err := os.WriteFile(envFile, []byte(strings.Join(envLines, "\n")+"\n"), 0o600); err != nil {
			cleanup()
			return nil, "", nil, func() {}, err
		}
	}
	return mounts, envFile, values, cleanup, nil
}

func Drain(events []trigger.Event, writer io.Writer) {
	for _, event := range events {
		fmt.Fprintln(writer, event.EventKind())
	}
}