package configkit

import "gitea.maximumdirect.net/eric/ConfigKit/internal/engine"

// Search is an immutable ordered description of possible host-file inputs.
// It is consumed only when passed to SearchConfig and used by a load.
type Search struct{ value engine.Search }

// FilenameGroup selects filenames in order for a directory search.
// Construct groups with NamedFilenames, GenericFilenames, or CustomFilenames.
type FilenameGroup struct{ value engine.FilenameGroup }

// SearchOptions controls whether a search must select a file.
type SearchOptions struct {
	// Required reports a missing-source error if the complete search is exhausted.
	Required bool
}

// DirectorySearchOptions selects the filename groups used by SearchDirectory.
type DirectorySearchOptions struct {
	// Filenames concatenates groups in order. A nil slice uses Named then Generic;
	// a non-nil empty slice selects no filenames.
	Filenames []FilenameGroup
}

// NamedFilenames selects <application>.yml followed by <application>.yaml.
func NamedFilenames() FilenameGroup { return FilenameGroup{value: engine.NamedFilenames()} }

// GenericFilenames selects config.yml, config.yaml, main.yml, and main.yaml.
func GenericFilenames() FilenameGroup { return FilenameGroup{value: engine.GenericFilenames()} }

// CustomFilenames selects literal filename components in the supplied order.
// Names cannot be empty or contain a directory component.
func CustomFilenames(names ...string) FilenameGroup {
	return FilenameGroup{value: engine.CustomFilenames(names...)}
}

// SearchDirectory describes a search within directory. Omitted options or a nil
// Filenames slice uses Named then Generic groups. Explicitly empty Filenames
// selects no names and does not resolve the directory base.
func SearchDirectory(directory string, supplied ...DirectorySearchOptions) Search {
	options := make([]engine.DirectorySearchOptions, len(supplied))
	for index, option := range supplied {
		if option.Filenames == nil {
			continue
		}
		options[index].Filenames = make([]engine.FilenameGroup, len(option.Filenames))
		for groupIndex, group := range option.Filenames {
			options[index].Filenames[groupIndex] = group.value
		}
	}
	return Search{value: engine.SearchDirectory(directory, options...)}
}

// Paths describes literal host-file candidates in the supplied order.
func Paths(paths ...string) Search { return Search{value: engine.Paths(paths...)} }

// Searches concatenates descriptions in order and snapshots their entries.
func Searches(searches ...Search) Search {
	values := make([]engine.Search, len(searches))
	for index, search := range searches {
		values[index] = search.value
	}
	return Search{value: engine.Searches(values...)}
}

// UnixSystemDirectories describes the conventional Unix system directories.
// Loading on an unsupported platform fails if this preset is reached.
func UnixSystemDirectories() Search { return Search{value: engine.UnixSystemDirectories()} }

// UserConfigDirectory describes searches rooted at the Go user-config directory.
func UserConfigDirectory() Search { return Search{value: engine.UserConfigDirectory()} }

// HomeDirectory describes searches rooted at the Go home directory.
func HomeDirectory() Search { return Search{value: engine.HomeDirectory()} }

// WorkingDirectory describes application-named files in the current directory.
func WorkingDirectory() Search { return Search{value: engine.WorkingDirectory()} }

// SearchConfig creates a source that selects the first matching host file when
// consumed by Load or LoadLayered. Without Required, exhausting the search uses
// the absent-input lifecycle. Description and option errors are reported while
// loading.
func SearchConfig(application string, search Search, supplied ...SearchOptions) Source {
	options := make([]engine.SearchOptions, len(supplied))
	for index, option := range supplied {
		options[index] = engine.SearchOptions{Required: option.Required}
	}
	return Source{value: engine.SearchConfig(application, search.value, options...)}
}