package configkit_test

import (
	"bytes"
	"os"
	"path/filepath"
	"reflect"
	"strconv"
	"strings"
	"testing"
	"testing/fstest"

	configkit "gitea.maximumdirect.net/eric/ConfigKit"
)

type layeredFacadeConfig struct {
	Settings map[string]string `yaml:"settings"`
	Count    int               `yaml:"count"`
	Enabled  bool              `yaml:"enabled"`
	List     []string          `yaml:"list"`
	Optional *string           `yaml:"optional"`
	Derived  string            `yaml:"derived"`
}

func TestFacadeLayeredMixedSourcesAndInspection(t *testing.T) {
	mainPath := filepath.Join(t.TempDir(), "main.yml")
	if err := os.WriteFile(mainPath, []byte("settings: {shared: main, secret: new-canary}\ncount: 0\nenabled: false\nlist: []\noptional: null\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	lower := configkit.NewFilesystem("bundle", fstest.MapFS{
		"main.yml":             &fstest.MapFile{Data: []byte("configkit: {imports: [{path: defaults.yml}]}\nsettings: {shared: lower, native: retained, secret: old-canary}\nlist: [lower]\n")},
		"defaults.yml":         &fstest.MapFile{Data: []byte("settings: {imported: retained}\n")},
		"overlays/testing.yml": &fstest.MapFile{Data: []byte("settings: {from_lower_namespace: retained}\n")},
	})
	selected := configkit.NewFilesystem("bundle", fstest.MapFS{
		"overlays/testing.yml": &fstest.MapFile{Data: []byte("settings: {shared: overlay}\n")},
	})
	checks := struct{ defaults, resolution, validation int }{}
	result, err := configkit.LoadLayered(configkit.Input{Source: configkit.File(mainPath)}, configkit.LayeredOptions[layeredFacadeConfig]{
		Underlays: []configkit.Underlay{
			{Inputs: []configkit.Input{
				{Source: lower.File("main.yml"), Imports: true},
				{Source: configkit.Mapping("programmatic-low", map[string]any{"settings": map[string]any{"mapping": "retained"}, "count": 7, "enabled": true})},
				{Source: lower.File("overlays/testing.yml")},
			}},
			{Inputs: []configkit.Input{{Source: configkit.Mapping("programmatic-high", map[string]any{
				"settings": map[string]any{"shared": "middle", "second": "retained"}, "list": []any{"middle"},
			})}}},
		},
		Overlay: "testing", OverlayFilesystem: &configkit.FilesystemContext{Root: ".", BaseDir: ".", FS: &selected},
		Overrides: []configkit.Override{{Path: configkit.Keys("settings", "shared"), Value: "cli", Flag: "--shared"}},
		Definition: configkit.Definition[layeredFacadeConfig]{
			Defaults: func() layeredFacadeConfig { checks.defaults++; return layeredFacadeConfig{} },
			Resolve: func(config *layeredFacadeConfig, resolution *configkit.Resolution) error {
				checks.resolution++
				if source, ok := resolution.Source("source-2"); !ok || source.Layer != configkit.LayerUnderlay || source.UnderlayIndex != 1 || source.Kind != configkit.SourceKindFilesystem {
					t.Errorf("resolver source = %#v, %v", source, ok)
				}
				configkit.Default(resolution, configkit.Keys("derived"), &config.Derived, config.Settings["native"], "derive from native", configkit.Keys("settings", "native"))
				return nil
			},
			Validate: func(config *layeredFacadeConfig, validation *configkit.Validation) { checks.validation++ },
			Secret:   func(path configkit.Path) bool { return path.String() == "/settings/secret" },
		},
	})
	if err != nil {
		t.Fatalf("layered load: %v, diagnostics %#v", err, err.(*configkit.LoadError).Diagnostics())
	}
	wantSettings := map[string]string{
		"shared": "cli", "secret": "new-canary", "native": "retained", "imported": "retained",
		"mapping": "retained", "from_lower_namespace": "retained", "second": "retained",
	}
	if !reflect.DeepEqual(result.Config.Settings, wantSettings) || result.Config.Count != 0 || result.Config.Enabled || result.Config.List == nil || len(result.Config.List) != 0 || result.Config.Optional != nil || result.Config.Derived != "retained" {
		t.Fatalf("configuration = %#v", result.Config)
	}
	if checks != (struct{ defaults, resolution, validation int }{1, 1, 1}) {
		t.Fatalf("lifecycle calls = %#v", checks)
	}
	sources := result.Sources()
	if len(sources) != 8 {
		t.Fatalf("sources = %#v", sources)
	}
	wantLayers := []configkit.Layer{configkit.LayerBase, configkit.LayerUnderlay, configkit.LayerUnderlay, configkit.LayerUnderlay, configkit.LayerUnderlay, configkit.LayerUnderlay, configkit.LayerOverlay, configkit.LayerCLI}
	wantIndexes := []int{0, 1, 1, 1, 1, 2, 0, 0}
	wantKinds := []configkit.SourceKind{configkit.SourceKindFile, configkit.SourceKindFilesystem, configkit.SourceKindFilesystem, configkit.SourceKindMapping, configkit.SourceKindFilesystem, configkit.SourceKindMapping, configkit.SourceKindFilesystem, configkit.SourceKindCLI}
	for index, source := range sources {
		if source.ID != "source-"+strconv.Itoa(index+1) || source.Layer != wantLayers[index] || source.UnderlayIndex != wantIndexes[index] || source.Kind != wantKinds[index] {
			t.Errorf("source %d = %#v", index, source)
		}
	}
	if sources[4].Path != sources[6].Path || sources[4].Label != sources[6].Label {
		t.Fatalf("namespace-collision fixture changed: %#v, %#v", sources[4], sources[6])
	}
	sources[1].Label = "changed"
	if result.Sources()[1].Label != "bundle/main.yml" {
		t.Fatal("source records alias retained metadata")
	}
	for _, test := range []struct {
		path string
		want configkit.Layer
	}{
		{"/settings/native", configkit.LayerUnderlay},
		{"/settings/shared", configkit.LayerCLI},
		{"/derived", configkit.LayerResolution},
	} {
		path, err := configkit.ParsePath(test.path)
		if err != nil {
			t.Fatal(err)
		}
		info, ok := result.Metadata().Lookup(path)
		if !ok || info.Origin.Layer != test.want {
			t.Errorf("%s metadata = %#v, %v", test.path, info, ok)
		}
	}
	container, ok := result.Metadata().Lookup(configkit.Keys("settings"))
	if !ok || len(container.Origin.Locations) < 4 {
		t.Fatalf("composite mapping origin = %#v, %v", container, ok)
	}
	explanation, ok := result.Explain(configkit.Keys("settings", "shared"))
	if !ok || len(explanation.History) < 5 || explanation.Origin.Layer != configkit.LayerCLI {
		t.Fatalf("shared history = %#v, %v", explanation, ok)
	}
	var effective, rendered bytes.Buffer
	if err := result.WriteEffective(&effective); err != nil {
		t.Fatal(err)
	}
	if err := result.WriteExplanation(&rendered, configkit.Keys("settings", "secret")); err != nil {
		t.Fatal(err)
	}
	if strings.Contains(effective.String()+rendered.String(), "old-canary") || strings.Contains(effective.String()+rendered.String(), "new-canary") || !strings.Contains(rendered.String(), "redacted") {
		t.Fatalf("secret rendering leaked: effective %q, explanation %q", effective.String(), rendered.String())
	}
}

func TestFacadeLayeredDisplacedDescendantRemainsInspectable(t *testing.T) {
	type config struct {
		Choice string `yaml:"choice"`
	}
	result, err := configkit.LoadLayered(configkit.Input{Source: configkit.Mapping("main", map[string]any{"choice": "flat"})}, configkit.LayeredOptions[config]{
		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{{Source: configkit.Mapping("lower", map[string]any{
			"choice": map[string]any{"nested": "historical"},
		})}}}},
	})
	if err != nil || result.Config.Choice != "flat" {
		t.Fatalf("replacement load = %#v, %v", result, err)
	}
	path := configkit.Keys("choice", "nested")
	explanation, ok := result.Explain(path)
	if !ok || explanation.Effective.Present || len(explanation.History) == 0 || explanation.History[0].Origin.Layer != configkit.LayerUnderlay {
		t.Fatalf("deleted descendant = %#v, %v", explanation, ok)
	}
}

func TestFacadeLayeredZeroUnderlaysMatchesOrdinaryLoad(t *testing.T) {
	filesystem := configkit.NewFilesystem("bundle", fstest.MapFS{
		"overlays/testing.yml": &fstest.MapFile{Data: []byte("value: selected\n")},
	})
	context := &configkit.FilesystemContext{Root: ".", BaseDir: ".", FS: &filesystem}
	source := configkit.Bytes("main", []byte("value: base\n"))
	type config struct {
		Value string `yaml:"value"`
	}
	ordinary, err := configkit.Load(source, configkit.Options[config]{Overlay: "testing", Filesystem: context})
	if err != nil {
		t.Fatal(err)
	}
	layered, err := configkit.LoadLayered(configkit.Input{Source: source}, configkit.LayeredOptions[config]{Overlay: "testing", OverlayFilesystem: context})
	if err != nil {
		t.Fatal(err)
	}
	if ordinary.Config != layered.Config || !reflect.DeepEqual(ordinary.Sources(), layered.Sources()) {
		t.Fatalf("ordinary = %#v, %#v; layered = %#v, %#v", ordinary.Config, ordinary.Sources(), layered.Config, layered.Sources())
	}
	var first, second bytes.Buffer
	if err := ordinary.WriteEffective(&first); err != nil {
		t.Fatal(err)
	}
	if err := layered.WriteEffective(&second); err != nil {
		t.Fatal(err)
	}
	if first.String() != second.String() {
		t.Fatalf("effective ordinary %q, layered %q", first.String(), second.String())
	}
	if ordinaryExplanation, ok := ordinary.Explain(configkit.Keys("value")); !ok {
		t.Fatal("ordinary explanation missing")
	} else if layeredExplanation, ok := layered.Explain(configkit.Keys("value")); !ok || !reflect.DeepEqual(ordinaryExplanation, layeredExplanation) {
		t.Fatalf("explanations differ: %#v, %#v", ordinaryExplanation, layeredExplanation)
	}
}

func TestFacadeLayeredOptionAndVersionFailures(t *testing.T) {
	type config struct {
		Version string `yaml:"version"`
	}
	namespace := configkit.NewFilesystem("bundle", fstest.MapFS{
		"overlays/testing.yml": &fstest.MapFile{Data: []byte("{}\n")},
	})
	for _, test := range []struct {
		name    string
		main    configkit.Input
		options []configkit.LayeredOptions[config]
		want    configkit.Code
	}{
		{"zero source", configkit.Input{}, nil, configkit.CodeSourceInvalid},
		{"multiple options", configkit.Input{Source: configkit.NoSource()}, []configkit.LayeredOptions[config]{{}, {}}, configkit.CodeOptionsInvalid},
		{"missing overlay context", configkit.Input{Source: configkit.NoSource()}, []configkit.LayeredOptions[config]{{Overlay: "testing"}}, configkit.CodeOptionsInvalid},
		{"selected file already acquired", configkit.Input{Source: configkit.NoSource()}, []configkit.LayeredOptions[config]{{
			Overlay: "testing", OverlayFilesystem: &configkit.FilesystemContext{Root: ".", BaseDir: ".", FS: &namespace},
			Underlays: []configkit.Underlay{{Inputs: []configkit.Input{{Source: namespace.File("overlays/testing.yml")}}}},
		}}, configkit.CodeOverlayRepeated},
		{"underlay version", configkit.Input{Source: configkit.NoSource()}, []configkit.LayeredOptions[config]{{
			Definition: configkit.Definition[config]{Version: &configkit.VersionRule{Path: configkit.Keys("version"), Check: func(configkit.Version, *configkit.Validation) error { return nil }}},
			Underlays:  []configkit.Underlay{{Inputs: []configkit.Input{{Source: configkit.Mapping("lower", map[string]any{"version": "forbidden"})}}}},
		}}, configkit.CodeUnderlayVersion},
	} {
		t.Run(test.name, func(t *testing.T) {
			_, err := configkit.LoadLayered(test.main, test.options...)
			loadError, ok := err.(*configkit.LoadError)
			if !ok || len(loadError.Diagnostics()) == 0 || loadError.Diagnostics()[0].Code != test.want {
				t.Fatalf("error = %#v, want %s", err, test.want)
			}
		})
	}
}

func TestFacadeLayeredExplicitHostOverlayWithoutMain(t *testing.T) {
	root := t.TempDir()
	if err := os.Mkdir(filepath.Join(root, "overlays"), 0o700); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(root, "overlays", "testing.yml"), []byte("value: selected\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	type config struct {
		Value string `yaml:"value"`
	}
	result, err := configkit.LoadLayered(configkit.Input{Source: configkit.NoSource()}, configkit.LayeredOptions[config]{
		Overlay: "testing", OverlayFilesystem: &configkit.FilesystemContext{Root: root, BaseDir: root},
	})
	if err != nil || result.Config.Value != "selected" || len(result.Sources()) != 1 || result.Sources()[0].Kind != configkit.SourceKindFile {
		t.Fatalf("explicit host overlay = %#v, %v", result, err)
	}
}