package configkit

// Layer identifies the precedence layer responsible for a configuration value.
type Layer string

const (
	LayerDefault    Layer = "default"
	LayerBase       Layer = "base"
	LayerUnderlay   Layer = "underlay"
	LayerOverlay    Layer = "overlay"
	LayerCLI        Layer = "cli"
	LayerResolution Layer = "resolution"
)

// SourceKind identifies how a configuration source was acquired, independent
// of its precedence layer.
type SourceKind string

const (
	SourceKindFile       SourceKind = "file"
	SourceKindFilesystem SourceKind = "filesystem"
	SourceKindBytes      SourceKind = "bytes"
	SourceKindReader     SourceKind = "reader"
	SourceKindMapping    SourceKind = "mapping"
	SourceKindCLI        SourceKind = "cli"
)

// ChangeKind identifies a recorded operation. The zero value is
// used for input and default origins.
type ChangeKind string

const (
	// ChangeDecoding records the built-in transition to canonical typed values.
	// It is inspection metadata, not an operation accepted by Resolution.Record.
	ChangeDecoding ChangeKind = "decoding"
	// ChangeInheritance records structural input expansion. It is inspection
	// metadata, not an operation accepted by Resolution.Record.
	ChangeInheritance    ChangeKind = "inheritance"
	ChangeDerivedDefault ChangeKind = "derived_default"
	ChangeNormalization  ChangeKind = "normalization"
)

// Severity classifies a diagnostic.
type Severity string

const (
	SeverityError   Severity = "error"
	SeverityWarning Severity = "warning"
)

// Code is a stable, machine-readable diagnostic classification.
type Code string

const (
	CodeSourceInvalid       Code = "source.invalid"
	CodeSourceMissing       Code = "source.missing"
	CodeSourcePermission    Code = "source.permission"
	CodeSourceRead          Code = "source.read"
	CodeSourceNotRegular    Code = "source.not_regular"
	CodeSourceLimitExceeded Code = "source.limit_exceeded"
	CodeSourceReaderUsed    Code = "source.reader_used"

	CodeYAMLInvalid           Code = "yaml.invalid"
	CodeYAMLEmpty             Code = "yaml.empty"
	CodeYAMLMultipleDocuments Code = "yaml.multiple_documents"
	CodeYAMLRootType          Code = "yaml.root_type"
	CodeYAMLDuplicateKey      Code = "yaml.duplicate_key"
	CodeYAMLTag               Code = "yaml.tag"
	CodeYAMLAnchor            Code = "yaml.anchor"
	CodeYAMLAlias             Code = "yaml.alias"
	CodeYAMLMergeKey          Code = "yaml.merge_key"
	CodeYAMLScalar            Code = "yaml.scalar"
	CodeYAMLDepthLimit        Code = "yaml.depth_limit"
	CodeYAMLNodeLimit         Code = "yaml.node_limit"

	CodeSchemaRoot            Code = "schema.root"
	CodeSchemaUnsupportedType Code = "schema.unsupported_type"
	CodeSchemaAmbiguousField  Code = "schema.ambiguous_field"
	CodeSchemaTag             Code = "schema.tag"
	CodeSchemaTextCodec       Code = "schema.text_codec"
	CodeSchemaInline          Code = "schema.inline"
	CodeSchemaCycle           Code = "schema.cycle"
	CodeSchemaProjectionLimit Code = "schema.projection_limit"
	CodeSchemaCodec           Code = "schema.codec"
	CodeSchemaNonFinite       Code = "schema.non_finite"
	CodeSchemaDynamicType     Code = "schema.dynamic_type"

	CodeDecodeType         Code = "decode.type"
	CodeDecodeNull         Code = "decode.null"
	CodeDecodeRange        Code = "decode.range"
	CodeDecodeDuration     Code = "decode.duration"
	CodeDecodeText         Code = "decode.text"
	CodeDecodeUnknownField Code = "decode.unknown_field"
	CodeDecodeArrayLength  Code = "decode.array_length"

	CodeOptionsInvalid     Code = "options.invalid"
	CodeOptionsUnavailable Code = "options.unavailable"

	CodeImportDisabled      Code = "import.disabled"
	CodeImportInvalid       Code = "import.invalid"
	CodeImportMissing       Code = "import.missing"
	CodeImportPermission    Code = "import.permission"
	CodeImportRead          Code = "import.read"
	CodeImportOutsideRoot   Code = "import.outside_root"
	CodeImportCycle         Code = "import.cycle"
	CodeImportRepeated      Code = "import.repeated"
	CodeImportLimitExceeded Code = "import.limit_exceeded"
	CodeImportVersion       Code = "import.version"
	CodeUnderlayVersion     Code = "underlay.version"

	CodeOverlayInvalid       Code = "overlay.invalid"
	CodeOverlayMissing       Code = "overlay.missing"
	CodeOverlayOutsideRoot   Code = "overlay.outside_root"
	CodeOverlayRepeated      Code = "overlay.repeated"
	CodeOverlayDirective     Code = "overlay.directive"
	CodeOverlayVersion       Code = "overlay.version"
	CodeOverlayLimitExceeded Code = "overlay.limit_exceeded"

	CodeComposeInvalid  Code = "compose.invalid"
	CodeComposeConflict Code = "compose.conflict"

	CodeVersionType       Code = "version.type"
	CodeVersionError      Code = "version.error"
	CodeVersionWarning    Code = "version.warning"
	CodeVersionHookFailed Code = "version.hook_failed"

	CodeResolveError            Code = "resolve.error"
	CodeResolveWarning          Code = "resolve.warning"
	CodeResolveHookFailed       Code = "resolve.hook_failed"
	CodeResolveInvalidPath      Code = "resolve.invalid_path"
	CodeResolveInvalidKind      Code = "resolve.invalid_kind"
	CodeResolveInvalidRecord    Code = "resolve.invalid_record"
	CodeResolveInvalidTarget    Code = "resolve.invalid_target"
	CodeResolveInvalidValue     Code = "resolve.invalid_value"
	CodeResolveUnrecordedChange Code = "resolve.unrecorded_change"

	CodeValidateError       Code = "validate.error"
	CodeValidateWarning     Code = "validate.warning"
	CodeValidateInvalidPath Code = "validate.invalid_path"
	CodeValidateMutation    Code = "validate.mutation"

	CodeSecretsInvalidPath   Code = "secrets.invalid_path"
	CodeSecretsMissing       Code = "secrets.missing"
	CodeSecretsPermission    Code = "secrets.permission"
	CodeSecretsRead          Code = "secrets.read"
	CodeSecretsNotRegular    Code = "secrets.not_regular"
	CodeSecretsInvalidName   Code = "secrets.invalid_name"
	CodeSecretsLimitExceeded Code = "secrets.limit_exceeded"
	CodeSecretsInvalidValue  Code = "secrets.invalid_value"
	CodeSecretsApplyFailed   Code = "secrets.apply_failed"

	CodeSecretRequired    Code = "secret.required"
	CodeSecretInvalidName Code = "secret.invalid_name"
	CodeSecretUnset       Code = "secret.unset"
	CodeSecretEmpty       Code = "secret.empty"

	CodeOverrideInvalidPath   Code = "override.invalid_path"
	CodeOverrideInvalidLabel  Code = "override.invalid_label"
	CodeOverrideInvalidValue  Code = "override.invalid_value"
	CodeOverrideDuplicate     Code = "override.duplicate"
	CodeOverrideOverlap       Code = "override.overlap"
	CodeOverrideDirective     Code = "override.directive"
	CodeOverrideVersion       Code = "override.version"
	CodeOverrideLimitExceeded Code = "override.limit_exceeded"

	CodeExplainLimitExceeded Code = "explain.limit_exceeded"

	CodeInheritanceInvalid Code = "inheritance.invalid"
	CodeInheritanceMissing Code = "inheritance.missing"
	CodeInheritanceCycle   Code = "inheritance.cycle"
	CodeInheritanceVersion Code = "inheritance.version"
)

// Location identifies a position in a configuration source. Zero line and column
// values mean that coordinates are unavailable or synthetic.
type Location struct {
	SourceID string
	Line     int
	Column   int
}

// SourceInfo describes a source discovered during a load. Kind identifies its
// acquisition, independent of Layer. Path is canonical for a host file and
// namespace-relative for a filesystem file; synthetic sources have no Path.
// Destination is the effective mapping path where this source contributes.
// UnderlayIndex is the one-based original underlay position, or zero for other
// sources. ImportedFrom identifies the declaration that included this source.
type SourceInfo struct {
	ID    string
	Label string
	Path  string
	// Destination is the effective mapping path. Imports inherit their declaring
	// document's path unless they append a YAML destination; overlay and CLI
	// sources use the root path.
	Destination   Path
	Layer         Layer
	Kind          SourceKind
	UnderlayIndex int
	ImportedFrom  *Location
	// VersionCheck is the sanitized source-local version declaration observed
	// during an enabled source-version load. It is nil otherwise.
	VersionCheck *SourceVersionCheck
}

// SourceVersionCheck describes a source-local version declaration observed
// during an enabled load. Text is empty when classification or conservative
// early-access redaction withholds it; Present and Null retain their meaning.
type SourceVersionCheck struct {
	Path     Path
	Version  Version
	Location *Location
	Redacted bool
}

// Diagnostic is a safe structured problem report. Message and source labels must
// never contain configuration values or other secrets.
type Diagnostic struct {
	Code     Code
	Severity Severity
	Path     Path
	Message  string
	Primary  *Location
	Related  []Location
}

// InheritanceStep identifies a concrete payload transfer. From and To name
// semantic value paths; Reference names the controlling destination `extends`
// path. Locations belong to that directive, not the transferred value.
type InheritanceStep struct {
	From      Path
	To        Path
	Reference Path
	Locations []Location
}

// Origin describes where an effective definition came from. Multiple locations
// represent a composite origin; resolution origins are synthetic and identify their
// operation instead of a file location. Inheritance records the concrete
// derivation path while Layer and Locations continue to identify value sources.
type Origin struct {
	Layer       Layer
	Locations   []Location
	Operation   ChangeKind
	Inheritance []InheritanceStep
}

// FieldInfo describes an effective configuration path.
type FieldInfo struct {
	Explicit bool
	Null     bool
	Origin   Origin
}

// Change describes a definition or application-resolution operation. Path can name
// an ancestor operation affecting the queried descendant. Historical values are
// intentionally not exposed by this record.
type Change struct {
	Path         Path
	Origin       Origin
	Previous     []Origin
	Reasons      []string
	Dependencies []Path
}

func cloneLocation(location *Location) *Location {
	if location == nil {
		return nil
	}
	cloned := *location
	return &cloned
}

func cloneLocations(locations []Location) []Location {
	if locations == nil {
		return nil
	}
	return append([]Location(nil), locations...)
}

func cloneSourceInfo(source SourceInfo) SourceInfo {
	source.Destination = source.Destination.clone()
	source.ImportedFrom = cloneLocation(source.ImportedFrom)
	source.VersionCheck = cloneSourceVersionCheck(source.VersionCheck)
	return source
}

func cloneSourceVersionCheck(value *SourceVersionCheck) *SourceVersionCheck {
	if value == nil {
		return nil
	}
	cloned := *value
	cloned.Path = value.Path.clone()
	cloned.Location = cloneLocation(value.Location)
	return &cloned
}

func cloneSourceInfos(sources []SourceInfo) []SourceInfo {
	if sources == nil {
		return nil
	}
	cloned := make([]SourceInfo, len(sources))
	for i, source := range sources {
		cloned[i] = cloneSourceInfo(source)
	}
	return cloned
}

func cloneOrigin(origin Origin) Origin {
	origin.Locations = cloneLocations(origin.Locations)
	if origin.Inheritance != nil {
		steps := make([]InheritanceStep, len(origin.Inheritance))
		for index, step := range origin.Inheritance {
			steps[index] = InheritanceStep{
				From: step.From.clone(), To: step.To.clone(), Reference: step.Reference.clone(),
				Locations: cloneLocations(step.Locations),
			}
		}
		origin.Inheritance = steps
	}
	return origin
}

func cloneFieldInfo(info FieldInfo) FieldInfo {
	info.Origin = cloneOrigin(info.Origin)
	return info
}

func cloneChange(change Change) Change {
	change.Path = change.Path.clone()
	change.Origin = cloneOrigin(change.Origin)
	if change.Previous != nil {
		previous := make([]Origin, len(change.Previous))
		for i, origin := range change.Previous {
			previous[i] = cloneOrigin(origin)
		}
		change.Previous = previous
	}
	change.Reasons = append([]string(nil), change.Reasons...)
	if change.Dependencies != nil {
		dependencies := make([]Path, len(change.Dependencies))
		for i, path := range change.Dependencies {
			dependencies[i] = path.clone()
		}
		change.Dependencies = dependencies
	}
	return change
}

func cloneDiagnostic(diagnostic Diagnostic) Diagnostic {
	diagnostic.Path = diagnostic.Path.clone()
	diagnostic.Primary = cloneLocation(diagnostic.Primary)
	diagnostic.Related = cloneLocations(diagnostic.Related)
	return diagnostic
}

func cloneDiagnostics(diagnostics []Diagnostic) []Diagnostic {
	if diagnostics == nil {
		return nil
	}
	cloned := make([]Diagnostic, len(diagnostics))
	for i, diagnostic := range diagnostics {
		cloned[i] = cloneDiagnostic(diagnostic)
	}
	return cloned
}