package engine

import (
	"reflect"
	"strings"
	"testing"
	"testing/fstest"
)

type groupedConfig struct {
	Version  string            `yaml:"version"`
	Settings map[string]string `yaml:"settings"`
	Port     int               `yaml:"port"`
	Derived  string            `yaml:"derived"`
}

func testGroupedLoad[T any](request loadRequest[T]) (*testResult[T], error) {
	loaded, err := loadGroupedWithSecretLookup(request, testSecretBinding(), func(string) (string, bool) { return "", false })
	return testLoaded(loaded), err
}

func TestGroupedLoadPrecedenceSourceOrderAndSingleLifecycle(t *testing.T) {
	filesystem := NewFilesystem("bundle", fstest.MapFS{
		"main.yml":          &fstest.MapFile{Data: []byte("configkit: {imports: [{path: imported.yml}]}\nversion: v1\nport: 5\nsettings: {shared: main}\n")},
		"imported.yml":      &fstest.MapFile{Data: []byte("settings: {imported: included}\n")},
		"overlays/test.yml": &fstest.MapFile{Data: []byte("settings: {shared: overlay}\n")},
	})
	checks := struct{ version, defaults, resolution, validation int }{}
	request := loadRequest[groupedConfig]{
		main: loadInput{source: filesystem.File("main.yml"), imports: true},
		underlays: []loadGroup{
			{inputs: []loadInput{
				{source: Mapping("low-a", map[string]any{"settings": map[string]any{"shared": "low", "a": "one"}, "port": "invalid until replaced"})},
				{source: Bytes("low-b", []byte("settings: {b: two}\n"))},
			}},
			{inputs: []loadInput{{source: Mapping("middle", map[string]any{"settings": map[string]any{"shared": "middle", "c": "three"}})}}},
		},
		definition: Definition[groupedConfig]{
			Version: &VersionRule{Path: Keys("version"), Check: func(version Version, validation *Validation) error {
				checks.version++
				if version.Text != "v1" {
					t.Errorf("version = %#v", version)
				}
				return nil
			}},
			Defaults: func() groupedConfig { checks.defaults++; return groupedConfig{Derived: "initial"} },
			Resolve: func(config *groupedConfig, resolution *Resolution) error {
				checks.resolution++
				Default(resolution, Keys("derived"), &config.Derived, "resolved", "set derived")
				return nil
			},
			Validate: func(config *groupedConfig, validation *Validation) { checks.validation++ },
		},
		overlay: "test", overlayFilesystem: &FilesystemContext{Root: ".", BaseDir: ".", FS: &filesystem},
		overrides: []Override{{Path: Keys("settings", "shared"), Value: "cli", Flag: "--shared"}},
	}
	result, err := testGroupedLoad(request)
	if err != nil {
		t.Fatalf("load: %v, diagnostics %#v", err, err.(*LoadError).Diagnostics())
	}
	wantSettings := map[string]string{"shared": "cli", "a": "one", "b": "two", "c": "three", "imported": "included"}
	if result.Config.Port != 5 || !reflect.DeepEqual(result.Config.Settings, wantSettings) {
		t.Fatalf("config = %#v", result.Config)
	}
	if checks != (struct{ version, defaults, resolution, validation int }{1, 1, 1, 1}) {
		t.Fatalf("lifecycle calls = %#v", checks)
	}
	sources := result.Sources()
	if len(sources) != 7 {
		t.Fatalf("sources = %#v", sources)
	}
	wantLayers := []Layer{LayerBase, LayerBase, LayerUnderlay, LayerUnderlay, LayerUnderlay, LayerOverlay, LayerCLI}
	wantIndexes := []int{0, 0, 1, 1, 2, 0, 0}
	for index, source := range sources {
		if source.ID != "source-"+string(rune('1'+index)) || source.Layer != wantLayers[index] || source.UnderlayIndex != wantIndexes[index] {
			t.Errorf("source %d = %#v", index, source)
		}
	}
	info, ok := result.Metadata().Lookup(Keys("settings", "shared"))
	if !ok || info.Origin.Layer != LayerCLI {
		t.Fatalf("effective shared metadata = %#v, %v", info, ok)
	}
	explanation, ok := result.Explain(Keys("settings", "shared"))
	if !ok || len(explanation.History) < 5 {
		t.Fatalf("shared explanation = %#v, %v", explanation, ok)
	}
	var layers []Layer
	for _, change := range explanation.History {
		if change.Origin.Layer != LayerDefault && (len(layers) == 0 || layers[len(layers)-1] != change.Origin.Layer) {
			layers = append(layers, change.Origin.Layer)
		}
	}
	if !reflect.DeepEqual(layers, []Layer{LayerUnderlay, LayerBase, LayerOverlay, LayerCLI}) {
		t.Fatalf("history layers = %#v", layers)
	}
}

func TestGroupedLoadAbsentMainAndVersionProtection(t *testing.T) {
	var observed Version
	request := loadRequest[groupedConfig]{
		main:      loadInput{source: NoSource()},
		underlays: []loadGroup{{}, {inputs: []loadInput{{source: Bytes("underlay", []byte("port: 7\n"))}}}},
		definition: Definition[groupedConfig]{Version: &VersionRule{Path: Keys("version"), Check: func(version Version, validation *Validation) error {
			observed = version
			return nil
		}}},
	}
	result, err := testGroupedLoad(request)
	if err != nil || result.Config.Port != 7 || observed.Present || len(result.Sources()) != 1 || result.Sources()[0].UnderlayIndex != 2 {
		t.Fatalf("underlay-only load = %#v, version %#v, %v", result, observed, err)
	}
	request.underlays[1].inputs[0].source = Bytes("underlay", []byte("version: forbidden\n"))
	_, err = testGroupedLoad(request)
	if got := groupedErrorCode(t, err); got != CodeUnderlayVersion {
		t.Fatalf("underlay version code = %s", got)
	}
	filesystem := NewFilesystem("bundle", fstest.MapFS{
		"main.yml":     &fstest.MapFile{Data: []byte("configkit: {imports: [{path: fragment.yml}]}\n")},
		"fragment.yml": &fstest.MapFile{Data: []byte("version: forbidden\n")},
	})
	request.underlays[1].inputs[0] = loadInput{source: filesystem.File("main.yml"), imports: true}
	_, err = testGroupedLoad(request)
	if got := groupedErrorCode(t, err); got != CodeImportVersion {
		t.Fatalf("import version code = %s", got)
	}
	request.underlays = []loadGroup{{}}
	request.definition.Defaults = func() groupedConfig { return groupedConfig{Port: 11} }
	result, err = testGroupedLoad(request)
	if err != nil || result.Config.Port != 11 || len(result.Sources()) != 0 {
		t.Fatalf("defaults-only load = %#v, %v", result, err)
	}
}

func TestGroupedLoadStrictConflictsRepetitionAndBudgets(t *testing.T) {
	main := loadInput{source: Bytes("main", []byte("port: 5\n"))}
	request := loadRequest[groupedConfig]{
		main: main,
		underlays: []loadGroup{{inputs: []loadInput{
			{source: Bytes("left", []byte("port: 1\n"))},
			{source: Bytes("right", []byte("port: 2\n"))},
		}}},
	}
	_, err := testGroupedLoad(request)
	if got := groupedErrorCode(t, err); got != CodeComposeConflict {
		t.Fatalf("strict conflict code = %s", got)
	}
	conflicting := NewFilesystem("bundle", fstest.MapFS{
		"main.yml":     &fstest.MapFile{Data: []byte("configkit: {imports: [{path: fragment.yml}]}\nport: 1\n")},
		"fragment.yml": &fstest.MapFile{Data: []byte("port: 2\n")},
	})
	request.main = loadInput{source: conflicting.File("main.yml"), imports: true}
	request.underlays = []loadGroup{{inputs: []loadInput{{source: Bytes("lower", []byte("port: 3\n"))}}}}
	_, err = testGroupedLoad(request)
	if got := groupedErrorCode(t, err); got != CodeComposeConflict {
		t.Fatalf("main/import conflict code = %s", got)
	}
	request.main = main
	filesystem := NewFilesystem("bundle", fstest.MapFS{"same.yml": &fstest.MapFile{Data: []byte("port: 1\n")}})
	file := filesystem.File("same.yml")
	request.underlays = []loadGroup{{inputs: []loadInput{{source: file}, {source: file}}}}
	_, err = testGroupedLoad(request)
	if got := groupedErrorCode(t, err); got != CodeImportRepeated {
		t.Fatalf("same-group repetition code = %s", got)
	}
	request.underlays = []loadGroup{{inputs: []loadInput{{source: file}}}, {inputs: []loadInput{{source: file}}}}
	if result, err := testGroupedLoad(request); err != nil || result.Config.Port != 5 || len(result.Sources()) != 3 {
		t.Fatalf("cross-group reuse = %#v, %v", result, err)
	}

	accounting := &importAccounting{sources: maxImportSources - 1}
	group := loadGroup{inputs: []loadInput{{source: Mapping("first", map[string]any{})}, {source: Mapping("second", map[string]any{})}}}
	_, _, diagnostics := acquireUnderlayGroup(group, 1, nil, accounting)
	if len(diagnostics) == 0 || diagnostics[0].Code != CodeSourceLimitExceeded {
		t.Fatalf("shared source budget = %#v", diagnostics)
	}
	accounting = &importAccounting{bytes: maxTotalBytes - 2}
	group.inputs = []loadInput{{source: Mapping("first", map[string]any{"port": "one"})}}
	_, _, diagnostics = acquireUnderlayGroup(group, 1, nil, accounting)
	if len(diagnostics) == 0 || diagnostics[0].Code != CodeSourceLimitExceeded {
		t.Fatalf("shared byte budget = %#v", diagnostics)
	}
}

func TestGroupedLoadInvalidIntermediateTypeCanBeReplaced(t *testing.T) {
	request := loadRequest[groupedConfig]{
		main:      loadInput{source: Bytes("main", []byte("port: 9\n"))},
		underlays: []loadGroup{{inputs: []loadInput{{source: Bytes("low", []byte("port: wrong\n"))}}}},
	}
	result, err := testGroupedLoad(request)
	if err != nil || result.Config.Port != 9 {
		t.Fatalf("final typed decode = %#v, %v", result, err)
	}
	request.main.source = Bytes("main", []byte("port: wrong\n"))
	_, err = testGroupedLoad(request)
	if got := groupedErrorCode(t, err); got != CodeDecodeType && got != CodeDecodeRange {
		t.Fatalf("final invalid type code = %s", got)
	}
}

func groupedErrorCode(t *testing.T, err error) Code {
	t.Helper()
	loadError, ok := err.(*LoadError)
	if !ok || len(loadError.Diagnostics()) == 0 {
		t.Fatalf("error = %#v", err)
	}
	if strings.Contains(loadError.Diagnostics()[0].Message, "wrong") {
		t.Fatal("raw value escaped diagnostics")
	}
	return loadError.Diagnostics()[0].Code
}