commandkit/execute.go

package commandkit

import (
	"context"
	"errors"
	"fmt"
	"io"
	"strconv"
	"strings"

	internalcobra "gitea.maximumdirect.net/eric/CommandKit/internal/cobra"
	commandmeta "gitea.maximumdirect.net/eric/CommandKit/internal/commandmeta"
)

// Execute parses and dispatches one invocation. args excludes the executable
// name. Supplied values are converted before command input construction; help
// does not construct caller inputs or run acquisition callbacks. It applies the
// parsed reporting selection, finalizes invocation presentation, and returns
// the resulting Outcome without exiting the process. Supplied streams remain
// caller-owned; nil destinations are replaced with io.Discard. A nil context
// returns an operational failure.
func (a *App) Execute(ctx context.Context, args []string, streams Streams) Outcome {
	current := newExecution(a, ctx, streams)
	if a == nil {
		err := errors.New("cannot execute commands on a nil app")
		return current.finalize(Failure(err.Error()).WithCause(err), nil, false)
	}
	if ctx == nil {
		err := errors.New("invocation context must not be nil")
		return current.finalize(Failure(err.Error()).WithCause(err), nil, false)
	}
	routedSnapshot := current.snapshot
	current.route = resolveEnteredRoute(args, routedSnapshot)
	current.recordRouteEvents()
	parsed := current.parse(current.route.args)
	current.reporter.applySelection(parsed.Reporting)
	current.recordSelectionEvents(parsed)
	current.submitDebugEvents()
	var outcome Outcome
	path := parsed.Path
	handlerRan := false
	if parsed.Failure != nil {
		outcome = Usage(parsed.Failure.Message)
	} else if current.route.kind == routeDiscovery {
		if parsed.HelpRequested {
			outcome = current.renderHelp(parsed.Path)
			path = clonePath(current.route.enteredPath)
		} else {
			entered := current.route.enteredPath.String()
			outcome = Usage(fmt.Sprintf("incomplete command path %q; use %q --help", entered, entered))
			path = clonePath(current.route.enteredPath)
		}
	} else {
		payload, ok := routedSnapshot.runners[parsed.Key]
		if !ok || payload == nil {
			outcome = current.renderHelp(parsed.Path)
		} else if parsed.HelpRequested || !payload.hasRun() {
			if _, err := payload.prepare(parsed.FlagValues, parsed.FlagSpellings, parsed.Operands, false); err != nil {
				outcome = classifyInputError(err)
			} else {
				outcome = current.renderHelp(parsed.Path)
			}
		} else {
			run, err := payload.prepare(parsed.FlagValues, parsed.FlagSpellings, parsed.Operands, true)
			if err != nil {
				outcome = classifyInputError(err)
			} else {
				handlerRan = true
				outcome = run(current)
			}
		}
	}
	return current.finalize(outcome, path, handlerRan)
}

type execution struct {
	app         *App
	ctx         context.Context
	streams     Streams
	reporter    *Reporter
	debugEvents []string
	options     commandmeta.ParseOptions
	snapshot    *routingSnapshot
	session     *internalcobra.Session
	route       routeResult
}

type commandExecution struct {
	invocation            Invocation
	renderHelpTargetsFunc func([]string) Outcome
}

func (current *execution) commandContext() commandExecution {
	return commandExecution{
		invocation:            current.invocation(),
		renderHelpTargetsFunc: current.renderHelpTargets,
	}
}

func (current *execution) invocation() Invocation {
	return Invocation{
		Context:       current.ctx,
		reporter:      current.reporter,
		enteredPath:   current.route.enteredPath.String(),
		canonicalPath: current.route.canonicalPath.String(),
	}
}

func (current commandExecution) renderHelpTargets(targets []string) Outcome {
	return current.renderHelpTargetsFunc(targets)
}

func newExecution(app *App, ctx context.Context, streams Streams) *execution {
	streams = normalizeStreams(streams)
	current := &execution{
		app:      app,
		ctx:      ctx,
		streams:  streams,
		reporter: newReporter(streams),
		options:  commandmeta.ParseOptions{Context: ctx, Out: streams.Out, Err: streams.Err},
	}
	if app != nil {
		current.snapshot = app.routeSnapshot()
	}
	return current
}

func (current *execution) parse(args []string) commandmeta.Result {
	if current.app == nil {
		return commandmeta.Result{Failure: &commandmeta.Failure{Message: "cannot parse commands on a nil app"}}
	}
	if current.session == nil {
		current.prepareSession()
	}
	return reduceReportingOccurrences(current.session.Parse(args))
}

func (current *execution) prepareSession() {
	if current.app == nil {
		return
	}
	if current.snapshot == nil {
		current.snapshot = current.app.routeSnapshot()
	}
	options := current.options
	if current.snapshot != nil {
		switch current.route.kind {
		case routeCanonical:
			options.FlagAliases = current.snapshot.flagAliases[current.route.canonicalPath.Key()].neutralRecords()
		case routeDiscovery:
			options.FlagAliases = current.snapshot.discoveryFlags[current.route.discoveryPath.Key()].neutralRecords()
		}
		current.session = internalcobra.Prepare(current.snapshot.metadata, options)
	}
}

func (current *execution) presentationSession() *internalcobra.Session {
	if current.app == nil {
		return nil
	}
	snapshot := current.app.routeSnapshot()
	if current.session == nil || current.snapshot != snapshot {
		current.snapshot = snapshot
		current.session = nil
		current.prepareSession()
	}
	return current.session
}

func (current *execution) renderHelp(path []string) Outcome {
	if current.app == nil {
		err := errors.New("cannot render help on a nil app")
		return Failure(err.Error()).WithCause(err)
	}
	session := current.presentationSession()
	view := current.app.helpView(current.route, current.snapshot)
	return current.app.renderHelpViewOutcomeWithSession(view, current.reporter, session)
}

func (current *execution) renderHelpTargets(targets []string) Outcome {
	if current.app == nil {
		err := errors.New("cannot render help on a nil app")
		return Failure(err.Error()).WithCause(err)
	}
	snapshot := current.app.routeSnapshot()
	if snapshot == nil {
		err := errors.New("cannot render help without command metadata")
		return Failure(err.Error()).WithCause(err)
	}
	route := resolveEnteredRoute(targets, snapshot)
	// Explicit help targets are paths, not command invocations with operands.
	// Discovery routes have no canonical path and retain only trailing options.
	if route.kind == routeUnknown || len(route.args) != len(route.canonicalPath) {
		session := internalcobra.Prepare(snapshot.metadata, current.options)
		view := commandmeta.HelpView{EnteredPath: targets, CanonicalPath: targets}
		return current.app.renderHelpViewOutcomeWithSession(view, current.reporter, session)
	}
	options := current.options
	switch route.kind {
	case routeCanonical:
		options.FlagAliases = snapshot.flagAliases[route.canonicalPath.Key()].neutralRecords()
	case routeDiscovery:
		options.FlagAliases = snapshot.discoveryFlags[route.discoveryPath.Key()].neutralRecords()
	}
	session := internalcobra.Prepare(snapshot.metadata, options)
	view := current.app.helpView(route, snapshot)
	return current.app.renderHelpViewOutcomeWithSession(view, current.reporter, session)
}

func (current *execution) usageLine(path []string) string {
	if current.app == nil {
		return "Usage: command [command]"
	}
	session := current.presentationSession()
	if session != nil {
		if usage, failure := session.UsageLine(path); failure == nil {
			return "Usage: " + usage
		}
	}
	return current.app.usageFallback()
}

func (current *execution) routeUsageLine() string {
	line := current.usageLine(clonePath(current.route.canonicalPath))
	canonical := strings.TrimSpace(current.app.identity.Name + " " + current.route.canonicalPath.String())
	entered := strings.TrimSpace(current.app.identity.Name + " " + current.route.enteredPath.String())
	line = strings.Replace(line, "Usage: "+canonical, "Usage: "+entered, 1)
	return line + "\nAlias for: " + canonical
}

func (current *execution) recordRouteEvents() {
	entered := current.route.enteredPath.String()
	canonical := current.route.canonicalPath.String()
	switch current.route.kind {
	case routeCanonical:
		if entered == canonical {
			if canonical == "" {
				current.debugEvents = append(current.debugEvents, "selected the application root command")
			} else {
				current.debugEvents = append(current.debugEvents, fmt.Sprintf("selected command path %q", canonical))
			}
		} else {
			current.debugEvents = append(current.debugEvents, fmt.Sprintf("resolved command alias %q to %q", entered, canonical))
		}
	case routeDiscovery:
		current.debugEvents = append(current.debugEvents, fmt.Sprintf("selected discovery route for prefix %q", entered))
	default:
		if entered != "" {
			current.debugEvents = append(current.debugEvents, fmt.Sprintf("no canonical route matched command path %q", entered))
		}
	}
}

func (current *execution) recordSelectionEvents(result commandmeta.Result) {
	mode := "ordinary"
	flagName := ""
	switch result.Reporting.Mode {
	case commandmeta.ReportingModeQuiet:
		mode, flagName = "quiet", "quiet"
	case commandmeta.ReportingModeVerbose:
		mode, flagName = "verbose", "verbose"
	case commandmeta.ReportingModeDebug:
		mode, flagName = "debug", "debug"
	}
	event := "selected ordinary reporting mode"
	if flagName != "" {
		event = fmt.Sprintf("selected %s reporting mode", mode)
		for index := len(result.FlagOccurrences) - 1; index >= 0; index-- {
			occurrence := result.FlagOccurrences[index]
			if occurrence.Name != flagName {
				continue
			}
			enabled, err := strconv.ParseBool(occurrence.RawValue)
			if err != nil || !enabled {
				continue
			}
			canonical := "--" + flagName
			if occurrence.Spelling != canonical {
				event += fmt.Sprintf(" using %s (alias for %s)", occurrence.Spelling, canonical)
			} else {
				event += fmt.Sprintf(" using %s", canonical)
			}
			break
		}
	}
	current.debugEvents = append(current.debugEvents, event)
	if result.Reporting.ProgressSet {
		state := "disabled"
		if result.Reporting.Progress {
			state = "enabled"
		}
		event := "explicitly " + state + " progress output"
		for index := len(result.FlagOccurrences) - 1; index >= 0; index-- {
			occurrence := result.FlagOccurrences[index]
			if occurrence.Name == "progress" {
				if occurrence.Spelling != "--progress" {
					event += fmt.Sprintf(" using %s (alias for --progress)", occurrence.Spelling)
				}
				break
			}
		}
		current.debugEvents = append(current.debugEvents, event)
	}
}

func (current *execution) submitDebugEvents() {
	events := current.debugEvents
	current.debugEvents = nil
	for _, event := range events {
		_ = current.reporter.Debug(event)
	}
}

func (current *execution) finalize(outcome Outcome, path []string, handlerRan bool) Outcome {
	if outcome.Kind == OutcomeUsage {
		details := append([]Detail(nil), outcome.Explanation.Details...)
		details = append(details, func(w io.Writer) error {
			line := current.usageText(path)
			if !strings.HasSuffix(line, "\n") {
				line += "\n"
			}
			_, err := io.WriteString(w, line)
			return err
		})
		outcome.Explanation.Details = details
	}
	var completion func(*Reporter)
	if handlerRan {
		completion = func(reporter *Reporter) {
			kind := outcome.Kind
			if kind == "" && outcome.Status == 0 && outcome.Domain == "" {
				kind = OutcomeSuccess
			}
			path := current.route.canonicalPath.String()
			_ = reporter.Debug(fmt.Sprintf("handler completed for %q with %s outcome and status %d", path, kind, outcome.Status))
		}
	}
	return current.reporter.finalize(outcome, completion)
}

func (current *execution) usageText(path []string) string {
	switch {
	case current.route.kind == routeDiscovery && current.app != nil:
		return fmt.Sprintf("Usage: %s %s [command]", current.app.identity.Name, current.route.enteredPath.String())
	case current.route.kind == routeCanonical && !current.route.enteredPath.Equal(current.route.canonicalPath):
		return current.routeUsageLine()
	default:
		return current.usageLine(path)
	}
}

func (a *App) usageLine(path []string) string {
	if a != nil {
		if usage, failure := internalcobra.UsageLine(a.routeSnapshot().metadata, path); failure == nil {
			return "Usage: " + usage
		}
	}
	return a.usageFallback()
}

func (a *App) usageFallback() string {
	name := "command"
	if a != nil && a.identity.Name != "" {
		name = a.identity.Name
	}
	return fmt.Sprintf("Usage: %s [command]", name)
}