package engine

import (
	"bytes"
	"reflect"
	"testing"
)

func TestMetadataHistoricalPaths(t *testing.T) {
	t.Parallel()
	result, err := testLoad[map[string]any](Bytes("base", []byte("retired: {child: 1}\nshape: {'0': base}\n'a/b~': {'': 2}\n")), Options[map[string]any]{
		Overrides: []Override{
			{Path: Keys("retired"), Value: nil, Flag: "--retired"},
			{Path: Keys("shape"), Value: []any{"replacement"}, Flag: "--shape"},
		},
	})
	if err != nil {
		t.Fatal(err)
	}
	metadata := result.Metadata()
	paths := metadata.HistoricalPaths()
	var got []string
	for _, path := range paths {
		got = append(got, path.String())
		if len(metadata.History(path)) == 0 {
			t.Fatalf("enumerated path %s has no history", path)
		}
	}
	want := []string{"", "/a~1b~0", "/a~1b~0/", "/retired", "/retired/child", "/shape", "/shape/0"}
	if !reflect.DeepEqual(got, want) {
		t.Fatalf("historical paths = %v, want %v", got, want)
	}
	if _, ok := metadata.Lookup(paths[4]); ok {
		t.Fatal("removed descendant remains effective")
	}
	if _, ok := metadata.Lookup(paths[6]); !ok {
		t.Fatal("enumerated numeric path cannot query the new sequence shape")
	}
	// Returned slices and nested paths must not alias retained metadata.
	paths[1].segments[0].key = "mutated"
	paths[2] = Keys("replacement")
	if again := metadata.HistoricalPaths(); again[1].String() != want[1] || again[2].String() != want[2] {
		t.Fatal("enumeration returned aliased paths")
	}
	if len((Metadata{}).HistoricalPaths()) != 0 {
		t.Fatal("zero metadata contains paths")
	}
}

func TestHistoricalPathsExposeHiddenBaseOwnershipWithoutResolvingBaseSecrets(t *testing.T) {
	t.Setenv("CONFIGKIT_HISTORY_UNUSED_PROD_KEY", "")
	t.Setenv("CONFIGKIT_HISTORY_TEST_KEY", "synthetic-test-key")
	type config struct {
		Credential  *Secret                      `yaml:"credential"`
		Definitions map[string]map[string]string `yaml:"definitions"`
	}
	for _, credential := range []string{"CONFIGKIT_HISTORY_TEST_KEY", "null"} {
		t.Run(credential, func(t *testing.T) {
			dir := t.TempDir()
			root := writeImportFile(t, dir, "main.yml", "configkit:\n  imports: [{path: first.yml}, {path: second.yml}]\ncredential: CONFIGKIT_HISTORY_UNUSED_PROD_KEY\n")
			writeImportFile(t, dir, "first.yml", "definitions: {recap: {prompt: recap}}\n")
			writeImportFile(t, dir, "second.yml", "definitions: {recap: {output: recap.md}}\n")
			writeImportFile(t, dir, "overlays/testing.yml", "definitions: null\ncredential: "+credential+"\n")
			result, err := testLoad[config](File(root), Options[config]{Imports: true, Overlay: "testing"})
			if err != nil {
				t.Fatal(err)
			}
			metadata := result.Metadata()
			found := false
			for _, path := range metadata.HistoricalPaths() {
				if path.String() != "/definitions/recap" {
					continue
				}
				found = true
				owners := map[string]bool{}
				for _, change := range metadata.History(path) {
					if change.Origin.Layer == LayerBase {
						for _, location := range change.Origin.Locations {
							owners[location.SourceID] = true
						}
					}
				}
				if len(owners) != 2 {
					t.Fatalf("hidden declaration owners = %v", owners)
				}
			}
			if !found {
				t.Fatal("hidden base declaration was not discoverable")
			}
		})
	}
}

func TestMetadataQueriesReturnDetachedRecords(t *testing.T) {
	t.Parallel()

	path := Keys("service", "workers")
	metadata := Metadata{
		effectivePaths:  map[string]Path{path.String(): path},
		historicalPaths: map[string][]Path{path.String(): {path}},
		fields: map[string]FieldInfo{
			path.String(): {
				Explicit: true,
				Origin: Origin{
					Layer:     LayerBase,
					Locations: []Location{{SourceID: "source-1", Line: 2, Column: 3}},
				},
			},
		},
		history: map[string][]Change{
			path.String(): {{
				Path:         path,
				Origin:       Origin{Layer: LayerResolution, Locations: []Location{{SourceID: "source-1"}}},
				Previous:     []Origin{{Layer: LayerDefault, Locations: []Location{{SourceID: "default"}}}},
				Reasons:      []string{"bounded worker count"},
				Dependencies: []Path{Keys("limits")},
			}},
		},
	}

	info, ok := metadata.Lookup(path)
	if !ok || !info.Explicit || !metadata.IsExplicit(path) {
		t.Fatalf("Lookup() = %#v, %v", info, ok)
	}
	info.Origin.Locations[0].SourceID = "mutated"
	again, _ := metadata.Lookup(path)
	if again.Origin.Locations[0].SourceID != "source-1" {
		t.Fatal("Lookup returned aliased locations")
	}

	history := metadata.History(path)
	history[0].Reasons[0] = "mutated"
	history[0].Previous[0].Locations[0].SourceID = "mutated"
	history[0].Dependencies[0].segments[0].key = "mutated"
	againHistory := metadata.History(path)
	if againHistory[0].Reasons[0] != "bounded worker count" ||
		againHistory[0].Previous[0].Locations[0].SourceID != "default" ||
		againHistory[0].Dependencies[0].String() != "/limits" {
		t.Fatal("History returned aliased nested records")
	}

	missing := Keys("missing")
	if _, ok := metadata.Lookup(missing); ok || metadata.IsExplicit(missing) || metadata.History(missing) != nil {
		t.Fatal("unknown path produced metadata")
	}
	if _, ok := metadata.Lookup(Path{}.Index(-1)); ok {
		t.Fatal("invalid path produced metadata")
	}
}

func TestResolutionInputKeepsDetachedEntryMetadata(t *testing.T) {
	t.Parallel()

	type configuration struct {
		Default  string            `yaml:"default"`
		Items    []string          `yaml:"items"`
		Values   map[string]string `yaml:"values"`
		Nullable *string           `yaml:"nullable"`
	}
	schema := mustSchemaFor[configuration](t)
	document := parseDocumentForDecode(t, "items: [first]\nvalues: {'0': key, 'a/b~': escaped}\nnullable: null\n")
	decoded, issues := decodeConfiguration(schema, reflect.ValueOf(configuration{Default: "retained"}), document)
	if len(issues) != 0 {
		t.Fatalf("decode issues = %#v", issues)
	}
	metadata := metadataFromDecoded(decoded)
	input := newResolutionInput(metadata, decoded.final, []SourceInfo{{
		ID: "source-1", Label: "decode.yml", Layer: LayerBase,
		ImportedFrom: &Location{SourceID: "parent", Line: 1, Column: 1},
	}})

	parsedItem, err := ParsePath("/items/0")
	if err != nil {
		t.Fatal(err)
	}
	parsedKey, err := ParsePath("/values/0")
	if err != nil {
		t.Fatal(err)
	}
	for _, path := range []Path{Path{}, Keys("default"), Keys("nullable"), parsedItem, parsedKey, Keys("values", "a/b~")} {
		if _, ok := input.lookup(path); !ok {
			t.Fatalf("entry path %s is missing", path)
		}
	}
	defaultInfo, _ := input.lookup(Keys("default"))
	nullInfo, _ := input.lookup(Keys("nullable"))
	if defaultInfo.Explicit || !nullInfo.Explicit || !nullInfo.Null {
		t.Fatalf("default = %#v, nullable = %#v", defaultInfo, nullInfo)
	}
	for _, path := range []Path{
		Keys("default", "child"),
		Keys("items", "0"),
		Keys("values").Index(0),
		Keys("items").Index(1),
	} {
		if _, ok := input.lookup(path); ok {
			t.Fatalf("entry lookup accepted %s", path)
		}
	}

	item, _ := input.lookup(parsedItem)
	item.Origin.Locations[0].SourceID = "mutated"
	source, ok := input.source("source-1")
	if !ok {
		t.Fatal("source is missing")
	}
	source.ImportedFrom.SourceID = "mutated"

	configurationAtEntry := decoded.value.Interface().(configuration)
	resolved := runResolution(&configurationAtEntry, func(value *configuration, resolution *Resolution) error {
		value.Items[0] = "normalized"
		resolution.Record(Keys("items"), ChangeNormalization, "normalized item")
		return nil
	}, schema, decoded, document, input)
	if len(resolved.diagnostics) != 0 {
		t.Fatalf("resolution diagnostics = %#v", resolved.diagnostics)
	}
	applyResolutionMetadata(&metadata, resolved)
	metadata.effectivePaths = effectivePathIndex(resolved.final)

	again, ok := input.lookup(parsedItem)
	if !ok || again.Origin.Locations[0].SourceID != "source-1" || again.Origin.Operation != "" {
		t.Fatalf("entry metadata changed after resolution = %#v, %v", again, ok)
	}
	againSource, ok := input.source("source-1")
	if !ok || againSource.ImportedFrom == nil || againSource.ImportedFrom.SourceID != "parent" {
		t.Fatalf("entry source changed = %#v, %v", againSource, ok)
	}
	if _, ok := input.source(""); ok {
		t.Fatal("empty source identity resolved")
	}
}

func TestQueriesRespectActualHistoricalAndEffectiveContainers(t *testing.T) {
	result, err := testLoad[map[string]any](Bytes("base", []byte("items: [1]\nm: {'0': 2}\nx: 3\nretired: {child: 4}\n")), Options[map[string]any]{Overrides: []Override{{Path: Keys("retired"), Value: "removed", Flag: "--retired"}}})
	if err != nil {
		t.Fatal(err)
	}
	for _, path := range []Path{Keys("items", "0"), Keys("m").Index(0), Keys("x", "missing"), Keys("items").Index(8)} {
		if _, ok := result.Metadata().Lookup(path); ok {
			t.Fatalf("invalid lookup %s", path)
		}
		if result.Metadata().History(path) != nil {
			t.Fatalf("invalid history %s", path)
		}
		if _, ok := result.Explain(path); ok {
			t.Fatalf("invalid explanation %s", path)
		}
		var out bytes.Buffer
		if err := result.WriteExplanation(&out, path); err == nil || out.Len() != 0 {
			t.Fatalf("invalid path wrote output: %s", path)
		}
	}
	for _, pointer := range []string{"/items/0", "/m/0"} {
		path, _ := ParsePath(pointer)
		if _, ok := result.Metadata().Lookup(path); !ok {
			t.Fatal("parsed path lost lookup")
		}
		if _, ok := result.Explain(path); !ok {
			t.Fatal("parsed path lost explanation")
		}
	}
	retired := Keys("retired", "child")
	if _, ok := result.Metadata().Lookup(retired); ok {
		t.Fatal("removed path remains effective")
	}
	if len(result.Metadata().History(retired)) == 0 {
		t.Fatal("removed history missing")
	}
	x, ok := result.Explain(retired)
	if !ok || x.Effective.Present || len(x.History) == 0 {
		t.Fatal("removed explanation missing")
	}
}