package commandkit

import commandmeta "gitea.maximumdirect.net/eric/CommandKit/internal/commandmeta"

// CompletionChoice is a literal suggested value and its optional description.
type CompletionChoice struct {
	Value       string
	Description string
}

// CompletionHint selects suggestions for a flag or positional value. Its zero
// value requests no value suggestions; hints do not constrain accepted input.
type CompletionHint struct {
	kind    completionHintKind
	choices []CompletionChoice
}

type completionHintKind uint8

const (
	completionNone completionHintKind = iota
	completionChoices
	completionFiles
	completionDirectories
)

// CompleteChoices suggests literal values. The supplied slice is copied.
func CompleteChoices(choices ...CompletionChoice) CompletionHint {
	return CompletionHint{kind: completionChoices, choices: append([]CompletionChoice(nil), choices...)}
}

// CompleteFiles requests shell filename completion.
func CompleteFiles() CompletionHint { return CompletionHint{kind: completionFiles} }

// CompleteDirectories requests shell directory completion.
func CompleteDirectories() CompletionHint { return CompletionHint{kind: completionDirectories} }

// NoCompletion requests no value suggestions.
func NoCompletion() CompletionHint { return CompletionHint{} }

func bridgeCompletion(hint CompletionHint) commandmeta.CompletionHint {
	result := commandmeta.CompletionHint{}
	switch hint.kind {
	case completionChoices:
		result.Kind = commandmeta.CompletionChoices
		for _, choice := range hint.choices {
			result.Choices = append(result.Choices, commandmeta.CompletionChoice{Value: choice.Value, Description: choice.Description})
		}
	case completionFiles:
		result.Kind = commandmeta.CompletionFiles
	case completionDirectories:
		result.Kind = commandmeta.CompletionDirectories
	}
	return result
}