package configkit

import (
	"errors"
	"math"
	"reflect"
	"strings"
	"testing"
	"time"
)

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

	type artifact struct {
		Output  string        `yaml:"output"`
		Timeout time.Duration `yaml:"timeout"`
	}
	type config struct {
		PollInterval time.Duration       `yaml:"poll_interval"`
		Timeout      time.Duration       `yaml:"timeout"`
		Artifacts    map[string]artifact `yaml:"artifacts"`
	}
	definition := Definition[config]{
		Defaults: func() config {
			return config{PollInterval: time.Minute, Timeout: 5 * time.Second}
		},
		Resolve: func(configuration *config, resolution *Resolution) error {
			Default(resolution, Keys("timeout"), &configuration.Timeout,
				configuration.PollInterval/10, "derived from poll interval", Keys("poll_interval"))
			for name, current := range configuration.Artifacts {
				path := Keys("artifacts", name)
				Default(resolution, path.Key("timeout"), &current.Timeout,
					configuration.Timeout, "inherited configuration timeout", Keys("timeout"))
				Normalize(resolution, path.Key("output"), &current.Output,
					strings.TrimSpace(current.Output), "trimmed surrounding whitespace")
				configuration.Artifacts[name] = current
			}
			resolution.Warning(Keys("timeout"), "using derived timeout", Keys("poll_interval"))
			return nil
		},
	}
	input := "poll_interval: 1m\nartifacts:\n  second: {output: ' second '}\n  first: {output: ' first '}\n"
	result, err := Load(Bytes("resolution.yml", []byte(input)), Options[config]{Definition: definition})
	if err != nil {
		t.Fatal(err)
	}
	if result.Config.Timeout != 6*time.Second {
		t.Fatalf("timeout = %s", result.Config.Timeout)
	}
	for name, want := range map[string]string{"first": "first", "second": "second"} {
		current := result.Config.Artifacts[name]
		if current.Timeout != 6*time.Second || current.Output != want {
			t.Errorf("artifact %q = %#v", name, current)
		}
	}
	if diagnostics := result.Diagnostics(); len(diagnostics) != 1 || diagnostics[0].Code != CodeResolveWarning || diagnostics[0].Primary == nil || len(diagnostics[0].Related) != 1 {
		t.Fatalf("diagnostics = %#v", diagnostics)
	}

	metadata := result.Metadata()
	timeout, ok := metadata.Lookup(Keys("timeout"))
	if !ok || timeout.Explicit || timeout.Origin.Layer != LayerResolution || timeout.Origin.Operation != ChangeDerivedDefault {
		t.Fatalf("timeout metadata = %#v, %v", timeout, ok)
	}
	output, ok := metadata.Lookup(Keys("artifacts", "first", "output"))
	if !ok || !output.Explicit || output.Origin.Operation != ChangeNormalization {
		t.Fatalf("output metadata = %#v, %v", output, ok)
	}
	history := metadata.History(Keys("timeout"))
	last := history[len(history)-1]
	if last.Origin.Operation != ChangeDerivedDefault || !reflect.DeepEqual(last.Reasons, []string{"derived from poll interval"}) || len(last.Dependencies) != 1 || last.Dependencies[0].String() != "/poll_interval" {
		t.Fatalf("timeout history = %#v", history)
	}
	wantOrder := []string{
		"/artifacts/first/output", "/artifacts/first/timeout",
		"/artifacts/second/output", "/artifacts/second/timeout", "/timeout",
	}
	gotOrder := make([]string, len(result.resolution))
	for index, snapshot := range result.resolution {
		gotOrder[index] = snapshot.change.Path.String()
	}
	if !reflect.DeepEqual(gotOrder, wantOrder) {
		t.Fatalf("resolution order = %#v", gotOrder)
	}
}

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

	type config struct {
		Optional *int `yaml:"optional"`
		Count    int  `yaml:"count"`
		Absent   int  `yaml:"absent"`
	}
	five := 5
	result, err := Load(Bytes("explicit.yml", []byte("optional: null\ncount: 0\n")), Options[config]{Definition: Definition[config]{
		Defaults: func() config { return config{Optional: &five, Count: 5, Absent: 5} },
		Resolve: func(configuration *config, resolution *Resolution) error {
			if !resolution.IsExplicit(Keys("optional")) || !resolution.IsExplicit(Keys("count")) || resolution.IsExplicit(Keys("absent")) {
				return errors.New("unexpected presence")
			}
			Default(resolution, Keys("optional"), &configuration.Optional, &five, "would derive optional")
			Default(resolution, Keys("count"), &configuration.Count, 9, "would derive count")
			Default(resolution, Keys("absent"), &configuration.Absent, 9, "derived absent value")
			return nil
		},
	}})
	if err != nil {
		var loadError *LoadError
		_ = errors.As(err, &loadError)
		t.Fatalf("%v: %#v", err, loadError.Diagnostics())
	}
	if result.Config.Optional != nil || result.Config.Count != 0 || result.Config.Absent != 9 {
		t.Fatalf("config = %#v", result.Config)
	}
	if len(result.Metadata().History(Keys("optional"))) != 2 || len(result.Metadata().History(Keys("count"))) != 2 || len(result.Metadata().History(Keys("absent"))) != 2 {
		t.Fatal("resolution history disagrees with explicitness")
	}
}

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

	type config struct {
		Value int `yaml:"value"`
		Other int `yaml:"other"`
	}
	result, err := Load(NoSource(), Options[config]{Definition: Definition[config]{
		Defaults: func() config { return config{Value: 5} },
		Resolve: func(configuration *config, resolution *Resolution) error {
			Default(resolution, Keys("value"), &configuration.Value, 5, "equal derived intent", Keys("other"))
			Default(resolution, Keys("value"), &configuration.Value, 7, "updated derived intent", Keys("other"))
			Normalize(resolution, Keys("value"), &configuration.Value, 7, "canonicalized value", Keys("other"))
			return nil
		},
	}})
	if err != nil {
		t.Fatal(err)
	}
	history := result.Metadata().History(Keys("value"))
	if len(history) != 2 {
		t.Fatalf("history = %#v", history)
	}
	change := history[1]
	if change.Origin.Operation != ChangeNormalization || !reflect.DeepEqual(change.Reasons, []string{"equal derived intent", "updated derived intent", "canonicalized value"}) || len(change.Dependencies) != 1 {
		t.Fatalf("coalesced change = %#v", change)
	}
}

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

	type item struct {
		Value string `yaml:"value"`
	}
	type config struct {
		Items map[string]item `yaml:"items"`
	}
	result, err := Load(Bytes("remove.yml", []byte("items:\n  keep: {value: 'yes'}\n  remove: {value: 'no'}\n")), Options[config]{Definition: Definition[config]{
		Resolve: func(configuration *config, resolution *Resolution) error {
			delete(configuration.Items, "remove")
			resolution.Record(Keys("items"), ChangeNormalization, "removed disabled entries")
			return nil
		},
	}})
	if err != nil {
		t.Fatal(err)
	}
	if _, exists := result.Config.Items["remove"]; exists {
		t.Fatal("removed entry remains")
	}
	if _, ok := result.Metadata().Lookup(Keys("items", "remove")); ok {
		t.Fatal("removed entry remains effective metadata")
	}
	if len(result.resolution) != 1 || result.resolution[0].before == nil || result.resolution[0].after == nil {
		t.Fatalf("snapshots = %#v", result.resolution)
	}
	result.Config.Items["keep"] = item{Value: "changed"}
	if mappingValue(t, result.resolution[0].after, "keep").Mapping[0].Value.Text != "yes" {
		t.Fatal("caller mutation changed private resolution snapshot")
	}
}

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

	type config struct {
		Values []int `yaml:"values"`
	}
	result, err := Load(Bytes("sequence.yml", []byte("values: [1, 2]\n")), Options[config]{Definition: Definition[config]{
		Resolve: func(configuration *config, resolution *Resolution) error {
			Normalize(resolution, Keys("values"), &configuration.Values, []int{3}, "replaced values")
			return nil
		},
	}})
	if err != nil {
		t.Fatal(err)
	}
	info, ok := result.Metadata().Lookup(Keys("values").Index(0))
	if !ok || !info.Explicit || info.Origin.Layer != LayerResolution || info.Origin.Operation != ChangeNormalization {
		t.Fatalf("element metadata = %#v, %v", info, ok)
	}
	if _, ok := result.Metadata().Lookup(Keys("values").Index(1)); ok {
		t.Fatal("removed sequence element remains effective")
	}
}

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

	type config struct {
		Value int `yaml:"value"`
	}
	tests := []struct {
		name    string
		resolve func(*config, *Resolution) error
		code    Code
	}{
		{name: "unrecorded", resolve: func(configuration *config, _ *Resolution) error {
			configuration.Value = 2
			return nil
		}, code: CodeResolveUnrecordedChange},
		{name: "unrelated target", resolve: func(_ *config, resolution *Resolution) error {
			unrelated := 1
			Normalize(resolution, Keys("value"), &unrelated, 2, "changed value")
			return nil
		}, code: CodeResolveInvalidTarget},
		{name: "invalid record kind", resolve: func(_ *config, resolution *Resolution) error {
			resolution.Record(Keys("value"), ChangeKind("other"), "invalid kind")
			return nil
		}, code: CodeResolveInvalidKind},
		{name: "invalid path", resolve: func(_ *config, resolution *Resolution) error {
			resolution.Record(Keys("unknown"), ChangeNormalization, "unknown field")
			return nil
		}, code: CodeResolveInvalidPath},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			result, err := Load(Bytes("invalid-resolution.yml", []byte("value: 1\n")), Options[config]{Definition: Definition[config]{Resolve: test.resolve}})
			assertLoadDiagnostic(t, result, err, test.code)
		})
	}
}

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

	type config struct {
		Number float64 `yaml:"number"`
		Value  int     `yaml:"value"`
	}
	tests := []struct {
		name    string
		resolve func(*config, *Resolution) error
		code    Code
	}{
		{name: "invalid helper value", resolve: func(configuration *config, resolution *Resolution) error {
			Normalize(resolution, Keys("number"), &configuration.Number, math.NaN(), "invalid number")
			return nil
		}, code: CodeResolveInvalidValue},
		{name: "reported error", resolve: func(_ *config, resolution *Resolution) error {
			resolution.Error(Keys("value"), "value cannot be resolved")
			return errors.New("CANARY_RESOLUTION_ERROR")
		}, code: CodeResolveError},
		{name: "returned error", resolve: func(_ *config, _ *Resolution) error {
			return errors.New("CANARY_RESOLUTION_ERROR")
		}, code: CodeResolveHookFailed},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			result, err := Load(Bytes("resolution-errors.yml", []byte("value: 1\nnumber: 1\n")), Options[config]{Definition: Definition[config]{Resolve: test.resolve}})
			loadError := assertLoadDiagnostic(t, result, err, test.code)
			for _, diagnostic := range loadError.Diagnostics() {
				if strings.Contains(diagnostic.Message, "CANARY") {
					t.Fatalf("diagnostic exposed returned error: %#v", diagnostic)
				}
			}
		})
	}
}

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

	type config struct {
		Value int `yaml:"value"`
	}
	var retained *Resolution
	if _, err := Load(NoSource(), Options[config]{Definition: Definition[config]{Resolve: func(_ *config, resolution *Resolution) error {
		retained = resolution
		return nil
	}}}); err != nil {
		t.Fatal(err)
	}
	defer func() {
		if recovered := recover(); recovered != closedCallbackContextMessage {
			t.Fatalf("panic = %#v", recovered)
		}
	}()
	retained.IsExplicit(Keys("value"))
}

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

	type config struct {
		Version string `yaml:"version"`
	}
	var retained *Validation
	if _, err := Load(Bytes("version-context.yml", []byte("version: one\n")), Options[config]{Definition: Definition[config]{
		Version: &VersionRule{Path: Keys("version"), Check: func(_ Version, validation *Validation) error {
			retained = validation
			return nil
		}},
	}}); err != nil {
		t.Fatal(err)
	}
	defer func() {
		if recovered := recover(); recovered != closedCallbackContextMessage {
			t.Fatalf("panic = %#v", recovered)
		}
	}()
	retained.Warning(Keys("version"), "too late")
}

func assertLoadDiagnostic[T any](t *testing.T, result *Result[T], err error, code Code) *LoadError {
	t.Helper()
	if result != nil || err == nil {
		t.Fatalf("result, err = %#v, %v", result, err)
	}
	var loadError *LoadError
	if !errors.As(err, &loadError) {
		t.Fatalf("error type = %T", err)
	}
	diagnostics := loadError.Diagnostics()
	if len(diagnostics) == 0 || diagnostics[0].Code != code {
		t.Fatalf("diagnostics = %#v", diagnostics)
	}
	return loadError
}