package engine

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

// assembledInput is the source/document handoff across schema and version checks.
type assembledInput struct {
	parsed      parsedSource
	document    *document.Node
	composition *composedDocument
	sources     []SourceInfo
}

func assembleBaseInput[T any](source Source, options Options[T]) (assembledInput, []Diagnostic) {
	parsed, diagnostics := parseSource(source, "source-1", defaultParseLimits())
	input := assembledInput{parsed: parsed, document: parsed.document}
	if len(diagnostics) != 0 {
		input.sources = sourceInfos(parsed.source)
		return input, diagnostics
	}
	if options.Imports {
		input.composition, input.sources, diagnostics = loadImportedDocuments(source, options.Filesystem, parsed, options.Definition.Version, defaultImportLimits())
		if len(diagnostics) != 0 {
			return input, diagnostics
		}
		input.document = input.composition.root
	} else {
		input.sources = sourceInfos(parsed.source)
		if options.Filesystem != nil && !activeOverlay(options.Overlay) {
			if diagnostic := validateFilesystemContext(source, options.Filesystem, parsed); diagnostic != nil {
				return input, []Diagnostic{*diagnostic}
			}
		}
	}
	if !options.Imports && input.document != nil {
		if diagnostics := disabledDirectiveDiagnostics(input.document, Path{}); len(diagnostics) != 0 {
			return input, diagnostics
		}
	}
	return input, nil
}

func applyInputLayers[T any](source Source, options Options[T], input assembledInput) (assembledInput, []Diagnostic) {
	if !activeOverlay(options.Overlay) && len(options.Overrides) == 0 {
		return input, nil
	}
	composition, diagnostics := compositionForInput(input)
	if len(diagnostics) != 0 {
		return input, diagnostics
	}
	if activeOverlay(options.Overlay) {
		composition, input.sources, diagnostics = loadSelectedOverlayDocument(
			source, options.Filesystem, input.parsed, composition, input.sources,
			options.Overlay, options.Definition.Version, defaultImportLimits(),
		)
		if len(diagnostics) != 0 {
			return input, diagnostics
		}
	}
	if len(options.Overrides) != 0 {
		composition, input.sources, diagnostics = applyOverrides(
			composition, input.sources, options.Overrides, options.Definition.Version, defaultImportLimits(),
		)
		if len(diagnostics) != 0 {
			return input, diagnostics
		}
	}
	input.composition = composition
	input.document = composition.root
	return input, nil
}

// compositionForInput initializes one handoff for overlays and CLI, including
// defaults-only CLI input. Raw source bytes and mapping keys retain their budgets.
func compositionForInput(input assembledInput) (*composedDocument, []Diagnostic) {
	if input.composition != nil {
		return input.composition, nil
	}
	if input.document == nil {
		return &composedDocument{root: &document.Node{Kind: document.Mapping}, origins: make(map[string]Origin)}, nil
	}
	composition, diagnostics := composeDocuments(input.document)
	if len(diagnostics) != 0 {
		return nil, diagnostics
	}
	composition.inputBytes = input.parsed.bytes
	composition.inputNodes = countInputNodes(input.document)
	return composition, nil
}