package configkit_test

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"os"
	"reflect"
	"strings"
	"testing"

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

var (
	_ error          = (*configkit.LoadError)(nil)
	_ fmt.Formatter  = configkit.Secret{}
	_ fmt.Stringer   = configkit.Path{}
	_ json.Marshaler = configkit.Secret{}
)

func TestFacadeValuesRemainRootOwned(t *testing.T) {
	t.Parallel()
	const packagePath = "gitea.maximumdirect.net/eric/ConfigKit"
	for _, candidate := range []reflect.Type{
		reflect.TypeFor[configkit.Path](), reflect.TypeFor[configkit.Source](),
		reflect.TypeFor[configkit.Secret](), reflect.TypeFor[configkit.Diagnostic](),
		reflect.TypeFor[configkit.LoadError](), reflect.TypeFor[configkit.Metadata](),
		reflect.TypeFor[configkit.Resolution](), reflect.TypeFor[configkit.Validation](),
		reflect.TypeFor[configkit.Version](), reflect.TypeFor[configkit.VersionRule](),
		reflect.TypeFor[configkit.FilesystemContext](), reflect.TypeFor[configkit.Override](),
		reflect.TypeFor[configkit.Definition[struct{}]](), reflect.TypeFor[configkit.Options[struct{}]](),
		reflect.TypeFor[configkit.Result[struct{}]](),
		reflect.TypeFor[configkit.ValueSnapshot](), reflect.TypeFor[configkit.ValueChange](),
		reflect.TypeFor[configkit.SecretReferenceInfo](), reflect.TypeFor[configkit.Explanation](),
		reflect.TypeFor[configkit.SecretFileResult](), reflect.TypeFor[configkit.SecretsReport](),
		reflect.TypeFor[configkit.SecretsError](),
	} {
		if candidate.PkgPath() != packagePath {
			t.Fatalf("type %s belongs to %q", candidate, candidate.PkgPath())
		}
	}
	secret := configkit.SecretEnv("SAFE_NAME")
	formatted := fmt.Sprintf("%#v", secret)
	encoded, err := json.Marshal(secret)
	if formatted == "" || err != nil || string(encoded) != `"SAFE_NAME"` {
		t.Fatalf("secret rendering = %q, %s, %v", formatted, encoded, err)
	}
	if got := configkit.Keys("a/b~").Index(0).String(); got != "/a~1b~0/0" {
		t.Fatalf("path = %q", got)
	}
	if got := (&configkit.LoadError{}).Error(); got != "configkit: configuration load failed" {
		t.Fatalf("zero LoadError = %q", got)
	}
}

func TestFacadeInspectionUsesFrozenState(t *testing.T) {
	t.Setenv("FACADE_INSPECTION_SECRET", "credential")

	type configuration struct {
		Value  string           `yaml:"value"`
		Secret configkit.Secret `yaml:"secret"`
	}
	result, err := configkit.Load[configuration](configkit.Bytes("inspection.yml", []byte("value: original\nsecret: FACADE_INSPECTION_SECRET\n")))
	if err != nil {
		t.Fatal(err)
	}
	if !result.Config.Secret.IsResolved() || result.Config.Secret.Value() != "credential" {
		t.Fatalf("secret = %#v", result.Config.Secret)
	}
	explanation, ok := result.Explain(configkit.Keys("value"))
	if !ok || explanation.Effective.YAML != "original\n" {
		t.Fatalf("explanation = %#v, %v", explanation, ok)
	}
	explanation.Effective.YAML = "mutated\n"
	result.Config.Value = "mutated"
	var effective bytes.Buffer
	if err := result.WriteEffective(&effective); err != nil || !strings.Contains(effective.String(), "value: original\n") || strings.Contains(effective.String(), "credential") {
		t.Fatalf("effective = %q, %v", effective.String(), err)
	}
	again, ok := result.Explain(configkit.Keys("value"))
	if !ok || again.Effective.YAML != "original\n" {
		t.Fatalf("inspection changed = %#v, %v", again, ok)
	}
	secret, ok := result.Explain(configkit.Keys("secret"))
	if !ok || secret.SecretReference == nil || secret.SecretReference.Name != "FACADE_INSPECTION_SECRET" {
		t.Fatalf("secret explanation = %#v, %v", secret, ok)
	}
	var explanationOutput bytes.Buffer
	if err := result.WriteExplanation(&explanationOutput, configkit.Keys("value")); err != nil || !strings.Contains(explanationOutput.String(), `path: "/value"`) {
		t.Fatalf("explanation output = %q, %v", explanationOutput.String(), err)
	}

	unknown := bytes.NewBufferString("unchanged")
	if err := result.WriteExplanation(unknown, configkit.Keys("unknown")); err == nil || unknown.String() != "unchanged" {
		t.Fatalf("unknown explanation = %q, %v", unknown.String(), err)
	}
	var nilResult *configkit.Result[configuration]
	if _, ok := nilResult.Explain(configkit.Keys("value")); ok {
		t.Fatal("nil result explained a path")
	}
	if err := nilResult.WriteEffective(io.Discard); err == nil {
		t.Fatal("nil result rendered effective configuration")
	}
}

func TestFacadeSecretsBootstrapUsesFacadeRecords(t *testing.T) {
	const (
		loadedName   = "FACADE_BOOTSTRAP_LOADED"
		existingName = "FACADE_BOOTSTRAP_EXISTING"
	)
	restore := func(name string) {
		value, present := os.LookupEnv(name)
		t.Cleanup(func() {
			if present {
				_ = os.Setenv(name, value)
			} else {
				_ = os.Unsetenv(name)
			}
		})
	}
	restore(loadedName)
	restore(existingName)
	if err := os.Unsetenv(loadedName); err != nil {
		t.Fatal(err)
	}
	if err := os.Setenv(existingName, ""); err != nil {
		t.Fatal(err)
	}
	directory := t.TempDir()
	if err := os.WriteFile(directory+"/"+loadedName, []byte("bootstrap\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(directory+"/"+existingName, []byte("ignored\n"), 0o600); err != nil {
		t.Fatal(err)
	}

	report, err := configkit.LoadSecretsDir(directory)
	if err != nil {
		t.Fatal(err)
	}
	entries := report.Entries()
	if len(entries) != 2 || os.Getenv(loadedName) != "bootstrap" {
		t.Fatalf("entries/environment = %#v / %q", entries, os.Getenv(loadedName))
	}
	status := map[string]configkit.SecretFileResult{}
	for _, entry := range entries {
		status[entry.Name] = entry
	}
	if status[loadedName].Status != configkit.SecretFileLoaded || status[existingName].Status != configkit.SecretFileSkippedExisting || !status[existingName].ExistingEmpty {
		t.Fatalf("statuses = %#v", status)
	}
	entries[0].Name = "mutated"
	if report.Entries()[0].Name == "mutated" {
		t.Fatal("report entries share mutable state")
	}
	var rendered bytes.Buffer
	if _, err := report.WriteTo(&rendered); err != nil || strings.Contains(rendered.String(), "bootstrap") || strings.Contains(rendered.String(), "ignored") {
		t.Fatalf("report rendering = %q, %v", rendered.String(), err)
	}

	failedReport, err := configkit.LoadSecretsDir("")
	var secretsError *configkit.SecretsError
	if failedReport == nil || !errors.As(err, &secretsError) || len(secretsError.Diagnostics()) != 1 || secretsError.Diagnostics()[0].Code != configkit.CodeSecretsInvalidPath {
		t.Fatalf("bootstrap failure = %#v / %#v", failedReport, err)
	}
}

func TestFacadeLoadBridgesLifecycleCallbacks(t *testing.T) {
	t.Setenv("FACADE_SECRET_NAME", "credential")

	type configuration struct {
		Version string            `yaml:"version"`
		Input   int               `yaml:"input"`
		Derived int               `yaml:"derived"`
		Secret  configkit.Secret  `yaml:"secret"`
		Labels  map[string]string `yaml:"labels"`
	}
	var retainedResolution *configkit.Resolution
	var retainedValidation *configkit.Validation
	versionCalls, defaultsCalls, resolveCalls, validateCalls := 0, 0, 0, 0
	definition := configkit.Definition[configuration]{
		Version: &configkit.VersionRule{Path: configkit.Keys("version"), Check: func(version configkit.Version, validation *configkit.Validation) error {
			versionCalls++
			retainedValidation = validation
			if !version.Present || version.Text != "1" {
				validation.Error(configkit.Keys("version"), "unsupported version")
			}
			return nil
		}},
		Defaults: func() configuration {
			defaultsCalls++
			return configuration{Derived: 1, Labels: map[string]string{"default": "kept"}}
		},
		Resolve: func(configuration *configuration, resolution *configkit.Resolution) error {
			resolveCalls++
			retainedResolution = resolution
			if !resolution.IsExplicit(configkit.Keys("input")) {
				resolution.Error(configkit.Keys("input"), "input is required")
			}
			input, ok := resolution.InputInfo(configkit.Keys("input"))
			if !ok || !input.Explicit {
				resolution.Error(configkit.Keys("input"), "missing input provenance")
			}
			source, ok := resolution.Source("source-1")
			if !ok || source.Label != "facade.yml" {
				resolution.Error(configkit.Keys("input"), "missing source")
			}
			configkit.Default(resolution, configkit.Keys("derived"), &configuration.Derived, configuration.Input*2, "derived from input", configkit.Keys("input"))
			return nil
		},
		Validate: func(configuration *configuration, validation *configkit.Validation) {
			validateCalls++
			retainedValidation = validation
			if !configuration.Secret.IsResolved() || configuration.Secret.Value() != "credential" {
				validation.Error(configkit.Keys("secret"), "secret did not resolve")
			}
		},
	}
	if versionCalls != 0 || defaultsCalls != 0 || resolveCalls != 0 || validateCalls != 0 {
		t.Fatal("callbacks ran while constructing options")
	}

	result, err := configkit.Load(configkit.Bytes("facade.yml", []byte("version: 1\ninput: 3\nsecret: FACADE_SECRET_NAME\n")), configkit.Options[configuration]{Definition: definition})
	if err != nil {
		t.Fatal(err)
	}
	if versionCalls != 1 || defaultsCalls != 1 || resolveCalls != 1 || validateCalls != 1 || result.Config.Derived != 6 {
		t.Fatalf("callback counts/configuration = %d/%d/%d/%d %#v", versionCalls, defaultsCalls, resolveCalls, validateCalls, result.Config)
	}
	derived, ok := result.Metadata().Lookup(configkit.Keys("derived"))
	if !ok || derived.Explicit || derived.Origin.Operation != configkit.ChangeDerivedDefault {
		t.Fatalf("derived metadata = %#v, %v", derived, ok)
	}
	if sources := result.Sources(); len(sources) != 1 || sources[0].Label != "facade.yml" {
		t.Fatalf("sources = %#v", sources)
	}
	if result.Diagnostics() != nil {
		t.Fatalf("diagnostics = %#v", result.Diagnostics())
	}
	for _, context := range []func(){
		func() { retainedResolution.IsExplicit(configkit.Keys("input")) },
		func() { retainedValidation.Warning(configkit.Keys("input"), "too late") },
	} {
		func() {
			defer func() {
				if recover() == nil {
					t.Fatal("retained callback context remained active")
				}
			}()
			context()
		}()
	}
}

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

	type configuration struct {
		Value int `yaml:"value"`
	}
	result, err := configkit.Load[configuration](configkit.Bytes("invalid.yml", []byte("value: wrong\n")))
	if result != nil || err == nil {
		t.Fatalf("result, err = %#v, %v", result, err)
	}
	var loadError *configkit.LoadError
	if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 || loadError.Diagnostics()[0].Code != configkit.CodeDecodeType {
		t.Fatalf("facade error = %#v", err)
	}
}