package configkit_test

import (
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"

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

type facadeDiffConfig struct {
	Value   string         `yaml:"value"`
	Count   int            `yaml:"count"`
	Items   []string       `yaml:"items"`
	Dynamic map[string]any `yaml:"dynamic"`
}

type facadeDiffSecretConfig struct {
	Secret configkit.Secret `yaml:"secret"`
}

func TestFacadeDiffReturnsDetachedCanonicalRecords(t *testing.T) {
	left, err := configkit.Load[facadeDiffConfig](configkit.Bytes("left.yml", []byte("value: before\ncount: 0\nitems: [one, two]\ndynamic: {}\n")))
	if err != nil {
		t.Fatalf("load left: %v", err)
	}
	right, err := configkit.Load[facadeDiffConfig](configkit.Bytes("right.yml", []byte("value: after\ncount: 0\nitems: [one, three]\ndynamic:\n  added: null\n")))
	if err != nil {
		t.Fatal(err)
	}

	differences, err := configkit.Diff(left, right)
	if err != nil {
		t.Fatal(err)
	}
	wantPaths := []string{"/dynamic/added", "/items", "/value"}
	if len(differences) != len(wantPaths) {
		t.Fatalf("differences = %#v", differences)
	}
	for index, difference := range differences {
		if got := difference.Path.String(); got != wantPaths[index] {
			t.Errorf("path[%d] = %q, want %q", index, got, wantPaths[index])
		}
	}
	if differences[0].Left.Present || !differences[0].Right.Present || differences[0].Right.YAML != "null\n" {
		t.Errorf("null/absence snapshots = %#v / %#v", differences[0].Left, differences[0].Right)
	}
	if differences[1].Left.YAML != "- one\n- two\n" || differences[1].Right.YAML != "- one\n- three\n" {
		t.Errorf("sequence snapshots = %#v / %#v", differences[1].Left, differences[1].Right)
	}

	left.Config.Value = "caller mutation"
	left.Config.Items[0] = "caller mutation"
	right.Config.Dynamic["added"] = "caller mutation"
	differences[2].Left.YAML = "record mutation"
	differences[2].Path = configkit.Keys("rewritten")

	again, err := configkit.Diff(left, right)
	if err != nil {
		t.Fatal(err)
	}
	if again[2].Path.String() != "/value" || again[2].Left.YAML != "before\n" || again[1].Left.YAML != "- one\n- two\n" {
		t.Fatalf("repeat diff changed = %#v", again)
	}
	explanation, ok := left.Explain(configkit.Keys("value"))
	if !ok || explanation.Effective.YAML != "before\n" {
		t.Fatalf("frozen explanation = %#v, %v", explanation, ok)
	}
}

func TestFacadeDiffRejectsUnavailableResults(t *testing.T) {
	type config struct {
		Value string `yaml:"value"`
	}
	loaded, err := configkit.Load[config](configkit.Bytes("valid.yml", []byte("value: valid\n")))
	if err != nil {
		t.Fatal(err)
	}
	var nilResult *configkit.Result[config]
	zeroResult := &configkit.Result[config]{Config: config{Value: "must not be inspected"}}
	for name, left := range map[string]*configkit.Result[config]{"nil": nilResult, "zero": zeroResult} {
		t.Run(name, func(t *testing.T) {
			if records, err := configkit.Diff(left, loaded); err == nil || records != nil {
				t.Fatalf("Diff = %#v, %v; want nil records and error", records, err)
			}
		})
	}
	if records, err := configkit.Diff(loaded, nilResult); err == nil || records != nil {
		t.Fatalf("right nil Diff = %#v, %v", records, err)
	}
}

func TestFacadeDiffIgnoresSourceAndResolutionHistory(t *testing.T) {
	type config struct {
		Count int `yaml:"count"`
	}
	defaults := configkit.Options[config]{Definition: configkit.Definition[config]{
		Defaults: func() config { return config{Count: 7} },
	}}
	defaulted, err := configkit.Load[config](configkit.NoSource(), defaults)
	if err != nil {
		t.Fatal(err)
	}
	explicit, err := configkit.Load[config](configkit.Bytes("explicit.yml", []byte("count: 7\n")))
	if err != nil {
		t.Fatal(err)
	}
	if differences, err := configkit.Diff(defaulted, explicit); err != nil || len(differences) != 0 {
		t.Fatalf("default/source difference = %#v, %v", differences, err)
	}

	zeroDefault, err := configkit.Load[config](configkit.NoSource(), configkit.Options[config]{Definition: configkit.Definition[config]{Defaults: func() config { return config{} }}})
	if err != nil {
		t.Fatal(err)
	}
	explicitZero, err := configkit.Load[config](configkit.Bytes("explicit-zero.yml", []byte("count: 0\n")))
	if err != nil {
		t.Fatal(err)
	}
	if differences, err := configkit.Diff(zeroDefault, explicitZero); err != nil || len(differences) != 0 {
		t.Fatalf("explicit/defaulted zero difference = %#v, %v", differences, err)
	}

	resolve := func(value string) configkit.Options[config] {
		return configkit.Options[config]{Definition: configkit.Definition[config]{Resolve: func(current *config, resolution *configkit.Resolution) error {
			current.Count = len(value) + 8
			resolution.Record(configkit.Keys("count"), configkit.ChangeNormalization, "set effective count")
			return nil
		}}}
	}
	resolvedA, err := configkit.Load[config](configkit.Bytes("a.yml", []byte("{}\n")), resolve("a"))
	if err != nil {
		t.Fatal(err)
	}
	resolvedB, err := configkit.Load[config](configkit.Bytes("b.yml", []byte("{}\n")), resolve("b"))
	if err != nil {
		t.Fatal(err)
	}
	if differences, err := configkit.Diff(resolvedA, resolvedB); err != nil || len(differences) != 0 {
		t.Fatalf("equal resolved values = %#v, %v", differences, err)
	}
}

func TestFacadeDiffUsesFrozenFilesAndRunsCallbacksOnlyDuringLoad(t *testing.T) {
	type config struct {
		Value string `yaml:"value"`
	}
	calls := 0
	options := configkit.Options[config]{Definition: configkit.Definition[config]{Defaults: func() config {
		calls++
		return config{}
	}}}
	dir := t.TempDir()
	paths := []string{filepath.Join(dir, "left.yml"), filepath.Join(dir, "right.yml")}
	for index, contents := range []string{"value: left\n", "value: right\n"} {
		if err := os.WriteFile(paths[index], []byte(contents), 0o600); err != nil {
			t.Fatal(err)
		}
	}
	left, err := configkit.Load[config](configkit.File(paths[0]), options)
	if err != nil {
		t.Fatal(err)
	}
	right, err := configkit.Load[config](configkit.File(paths[1]), options)
	if err != nil {
		t.Fatal(err)
	}
	if calls != 2 {
		t.Fatalf("defaults calls after loads = %d", calls)
	}
	for _, path := range paths {
		if err := os.Remove(path); err != nil {
			t.Fatal(err)
		}
	}
	differences, err := configkit.Diff(left, right)
	if err != nil || len(differences) != 1 || differences[0].Path.String() != "/value" {
		t.Fatalf("Diff after removing files = %#v, %v", differences, err)
	}
	if calls != 2 {
		t.Fatalf("defaults reran during Diff: %d calls", calls)
	}
}

func TestFacadeDiffCombinesSecretSensitivityAndLoadErrors(t *testing.T) {
	t.Setenv("FACADE_DIFF_SECRET", "credential-one")
	secretOptions := configkit.Options[facadeDiffSecretConfig]{Definition: configkit.Definition[facadeDiffSecretConfig]{Secret: func(path configkit.Path) bool {
		return path.String() == "/secret"
	}}}
	left, err := configkit.Load[facadeDiffSecretConfig](configkit.Bytes("left.yml", []byte("secret: FACADE_DIFF_SECRET\n")), secretOptions)
	if err != nil {
		t.Fatal(err)
	}
	t.Setenv("FACADE_DIFF_SECRET", "credential-two")
	right, err := configkit.Load[facadeDiffSecretConfig](configkit.Bytes("right.yml", []byte("secret: FACADE_DIFF_SECRET\n")), secretOptions)
	if err != nil {
		t.Fatal(err)
	}
	if differences, err := configkit.Diff(left, right); err != nil || len(differences) != 0 {
		t.Fatalf("credential rotation = %#v, %v", differences, err)
	}
	t.Setenv("OTHER_FACADE_DIFF_SECRET", "other-credential")
	otherReference, err := configkit.Load[facadeDiffSecretConfig](configkit.Bytes("other.yml", []byte("secret: OTHER_FACADE_DIFF_SECRET\n")), secretOptions)
	if err != nil {
		t.Fatal(err)
	}
	differences, err := configkit.Diff(left, otherReference)
	if err != nil || len(differences) != 1 || !differences[0].HiddenChanged || !differences[0].Left.Redacted || !differences[0].Right.Redacted {
		t.Fatalf("reference change = %#v, %v", differences, err)
	}
	if strings.Contains(differences[0].Left.YAML+differences[0].Right.YAML, "credential") {
		t.Fatalf("credential leaked: %#v", differences)
	}

	invalidLeft, leftErr := configkit.Load[facadeDiffSecretConfig](configkit.Bytes("invalid-left.yml", []byte("unknown: true\n")))
	if invalidLeft != nil || leftErr == nil {
		t.Fatalf("invalid left load = %#v, %v", invalidLeft, leftErr)
	}
	var loadError *configkit.LoadError
	if !errors.As(leftErr, &loadError) {
		t.Fatalf("left load error = %T, want *configkit.LoadError", leftErr)
	}
	invalidRight, rightErr := configkit.Load[facadeDiffSecretConfig](configkit.Bytes("invalid-right.yml", []byte("unknown: true\n")))
	if invalidRight != nil || rightErr == nil {
		t.Fatalf("invalid right load = %#v, %v", invalidRight, rightErr)
	}
	if !errors.As(rightErr, &loadError) {
		t.Fatalf("right load error = %T, want *configkit.LoadError", rightErr)
	}
}