package commandkit_test

import (
	"bytes"
	"context"
	"errors"
	"io"
	"strings"
	"testing"

	commandkit "gitea.maximumdirect.net/eric/CommandKit"
	configkit "gitea.maximumdirect.net/eric/ConfigKit"
	"gitea.maximumdirect.net/eric/promptkit"
)

func TestPromptKitScopeUsesCapturedInspectionAndSelectedInputs(t *testing.T) {
	type appContext struct{ marker string }
	type contextKey struct{}

	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
		Main: &configkit.Input{Source: configkit.Mapping("local fixture", map[string]any{
			"backends": map[string]any{"local": map[string]any{"endpoint": "https://example.invalid/v1"}},
			"profiles": map[string]any{"base.v1": map[string]any{"backend": "local", "model": "fixture-model"}},
		})},
	}})
	if err != nil {
		t.Fatalf("construct PromptKit engine: %v", err)
	}
	inspection, err := engine.InspectConfiguration()
	if err != nil {
		t.Fatalf("inspect PromptKit engine: %v", err)
	}

	ctx := context.WithValue(context.Background(), contextKey{}, "caller-context")
	selection := commandkit.Selection{Config: commandkit.Supplied[string]{Value: "main.yml", Set: true}, Overlay: commandkit.Supplied[string]{Value: "dev", Set: true}}
	loaderCalls := 0
	var receivedSelections []commandkit.Selection
	scope, err := commandkit.NewPromptKitScope(func(gotContext context.Context, gotSelection commandkit.Selection, gotAppContext appContext) (*promptkit.Engine, error) {
		loaderCalls++
		receivedSelections = append(receivedSelections, gotSelection)
		if gotContext != ctx || gotContext.Value(contextKey{}) != "caller-context" {
			t.Fatal("PromptKit loader did not receive the caller context")
		}
		if gotAppContext.marker != "app-state" {
			t.Fatalf("loader app context = %+v", gotAppContext)
		}
		return engine, nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if scope.Name != "promptkit" || len(scope.Operations) != 4 {
		t.Fatalf("scope declaration = %+v", scope)
	}

	acquired, err := scope.Acquire(ctx, commandkit.ConfigRequest{Operation: commandkit.ConfigShow, Selection: selection}, appContext{marker: "app-state"})
	if err != nil {
		t.Fatalf("acquire PromptKit scope: %v", err)
	}
	var gotEffective, wantEffective bytes.Buffer
	if err := acquired.Value.Effective.WriteEffective(&gotEffective); err != nil {
		t.Fatal(err)
	}
	if err := inspection.WriteEffective(&wantEffective); err != nil || gotEffective.String() != wantEffective.String() {
		t.Fatalf("native effective output = (%q, %v), want %q", gotEffective.String(), err, wantEffective.String())
	}
	if len(acquired.Value.Sources.Sources()) != len(inspection.Sources()) {
		t.Fatalf("source inventory = %#v, want %#v", acquired.Value.Sources.Sources(), inspection.Sources())
	}
	path := configkit.Keys("profiles", "base.v1", "model")
	var gotExplanation, wantExplanation bytes.Buffer
	if err := acquired.Value.Explanation.WriteExplanation(&gotExplanation, path); err != nil {
		t.Fatal(err)
	}
	if err := inspection.WriteExplanation(&wantExplanation, path); err != nil || gotExplanation.String() != wantExplanation.String() {
		t.Fatalf("native explanation = (%q, %v), want %q", gotExplanation.String(), err, wantExplanation.String())
	}
	if loaderCalls != 1 {
		t.Fatalf("loader called %d times, want once", loaderCalls)
	}
	if len(receivedSelections) != 1 || receivedSelections[0] != selection {
		t.Fatalf("loader selection = %#v, want %#v", receivedSelections, selection)
	}

	app, err := commandkit.New(commandkit.Identity{Name: "example"})
	if err != nil {
		t.Fatal(err)
	}
	if err := commandkit.RegisterConfig(app, commandkit.ConfigSuite[appContext]{
		NewContext: func() appContext { return appContext{marker: "app-state"} },
		Scopes:     []commandkit.ConfigScope[appContext]{scope},
	}); err != nil {
		t.Fatal(err)
	}
	var show bytes.Buffer
	outcome := app.Execute(ctx, []string{"config", "show", "--scope", "promptkit", "--config", "main.yml", "--overlay", "dev"}, commandkit.Streams{Out: &show, Err: io.Discard})
	if outcome.Kind != commandkit.OutcomeSuccess || show.String() != wantEffective.String() {
		t.Fatalf("config show = (%#v, %q), want native output %q", outcome, show.String(), wantEffective.String())
	}
	var sources bytes.Buffer
	outcome = app.Execute(ctx, []string{"config", "sources", "--scope", "promptkit", "--format", "yaml"}, commandkit.Streams{Out: &sources, Err: io.Discard})
	if outcome.Kind != commandkit.OutcomeSuccess || !strings.Contains(sources.String(), "label: local fixture") {
		t.Fatalf("config sources = (%#v, %q), want captured PromptKit source", outcome, sources.String())
	}
	var explanation bytes.Buffer
	outcome = app.Execute(ctx, []string{"config", "explain", "--scope", "promptkit", "--path", path.String()}, commandkit.Streams{Out: &explanation, Err: io.Discard})
	if outcome.Kind != commandkit.OutcomeSuccess || explanation.String() != wantExplanation.String() {
		t.Fatalf("config explain = (%#v, %q), want native output %q", outcome, explanation.String(), wantExplanation.String())
	}

	callsBeforeDiscovery := loaderCalls
	outcome = app.Execute(ctx, []string{"config", "scopes"}, commandkit.Streams{Out: io.Discard, Err: io.Discard})
	if outcome.Kind != commandkit.OutcomeSuccess || loaderCalls != callsBeforeDiscovery {
		t.Fatalf("metadata discovery outcome=%#v loader calls=%d", outcome, loaderCalls)
	}
}

func TestPromptKitScopeAggregateOrderAndConfigurationOnlyRegistration(t *testing.T) {
	engine, err := promptkit.NewEngine(promptkit.Config{})
	if err != nil {
		t.Fatal(err)
	}
	scope, err := commandkit.NewPromptKitScope(func(context.Context, commandkit.Selection, struct{}) (*promptkit.Engine, error) {
		return engine, nil
	})
	if err != nil {
		t.Fatal(err)
	}
	app, err := commandkit.New(commandkit.Identity{Name: "example"})
	if err != nil {
		t.Fatal(err)
	}
	if err := commandkit.RegisterConfig(app, commandkit.ConfigSuite[struct{}]{Scopes: []commandkit.ConfigScope[struct{}]{
		{Name: "app", Operations: []commandkit.ConfigOperation{commandkit.ConfigShow}, Acquire: func(context.Context, commandkit.ConfigRequest, struct{}) (commandkit.Acquired[commandkit.ConfigView], error) {
			return commandkit.Acquired[commandkit.ConfigView]{Value: commandkit.ConfigView{Effective: effectiveYAML("app: true\n")}}, nil
		}}, scope,
	}}); err != nil {
		t.Fatal(err)
	}
	var output bytes.Buffer
	outcome := app.Execute(context.Background(), []string{"config", "show", "--scope", "all"}, commandkit.Streams{Out: &output, Err: io.Discard})
	if outcome.Kind != commandkit.OutcomeSuccess {
		t.Fatalf("aggregate show outcome = %#v", outcome)
	}
	appIndex, promptkitIndex := strings.Index(output.String(), "# scope: app"), strings.Index(output.String(), "# scope: promptkit")
	if appIndex < 0 || promptkitIndex <= appIndex {
		t.Fatalf("aggregate order = %q", output.String())
	}
	var scopes bytes.Buffer
	outcome = app.Execute(context.Background(), []string{"config", "scopes"}, commandkit.Streams{Out: &scopes, Err: io.Discard})
	if outcome.Kind != commandkit.OutcomeSuccess || !strings.Contains(scopes.String(), "promptkit: validate, show, sources, explain") {
		t.Fatalf("configuration scope discovery = (%#v, %q)", outcome, scopes.String())
	}
	outcome = app.Execute(context.Background(), []string{"help", "promptkit"}, commandkit.Streams{Out: io.Discard, Err: io.Discard})
	if outcome.Kind != commandkit.OutcomeUsage {
		t.Fatalf("configuration-only install exposed promptkit definition commands: %#v", outcome)
	}
}

func TestPromptKitScopeErrorsPreserveIdentityAndRejectNilInputs(t *testing.T) {
	if _, err := commandkit.NewPromptKitScope[struct{}](nil); err == nil {
		t.Fatal("nil loader was accepted")
	}
	var nilEngine *promptkit.Engine
	if _, err := nilEngine.InspectConfiguration(); !errors.Is(err, promptkit.ErrInvalidConfig) {
		t.Fatalf("PromptKit nil engine identity = %v", err)
	}

	loadErr := errors.Join(promptkit.ErrInvalidConfig, errors.New("loader context"))
	scope, err := commandkit.NewPromptKitScope(func(context.Context, commandkit.Selection, struct{}) (*promptkit.Engine, error) {
		return nil, loadErr
	})
	if err != nil {
		t.Fatal(err)
	}
	_, err = scope.Acquire(context.Background(), commandkit.ConfigRequest{}, struct{}{})
	if err != loadErr || !errors.Is(err, promptkit.ErrInvalidConfig) {
		t.Fatalf("loader error = %v, want original error identity %v", err, loadErr)
	}

	nilScope, err := commandkit.NewPromptKitScope(func(context.Context, commandkit.Selection, struct{}) (*promptkit.Engine, error) {
		return nil, nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if _, err := nilScope.Acquire(context.Background(), commandkit.ConfigRequest{}, struct{}{}); err == nil || !strings.Contains(err.Error(), "nil engine") {
		t.Fatalf("nil engine acquisition error = %v", err)
	}

	negativeRetries := -1
	invalidEngine, err := promptkit.NewEngine(promptkit.Config{TransientRetries: &negativeRetries})
	if invalidEngine != nil || !errors.Is(err, promptkit.ErrInvalidConfig) {
		t.Fatalf("invalid PromptKit construction = (%v, %v)", invalidEngine, err)
	}

	invalidEngine, err = promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{Main: &configkit.Input{
		Source: configkit.Mapping("invalid inheritance", map[string]any{
			"profiles": map[string]any{"child": map[string]any{"extends": "missing"}},
		}),
	}}})
	if invalidEngine != nil || !errors.Is(err, promptkit.ErrInvalidConfig) {
		t.Fatalf("invalid PromptKit profile construction = (%v, %v)", invalidEngine, err)
	}
	var configLoadErr *configkit.LoadError
	if !errors.As(err, &configLoadErr) {
		t.Fatalf("invalid PromptKit construction did not preserve ConfigKit LoadError: %v", err)
	}
	failedScope, scopeErr := commandkit.NewPromptKitScope(func(context.Context, commandkit.Selection, struct{}) (*promptkit.Engine, error) {
		return nil, err
	})
	if scopeErr != nil {
		t.Fatal(scopeErr)
	}
	failed, scopeErr := failedScope.Acquire(context.Background(), commandkit.ConfigRequest{}, struct{}{})
	var acquiredLoadErr *configkit.LoadError
	if scopeErr != err || !errors.As(scopeErr, &acquiredLoadErr) || acquiredLoadErr != configLoadErr || len(failed.Diagnostics) == 0 {
		t.Fatalf("scope load error = (%v, %+v), want original LoadError and diagnostics", scopeErr, failed)
	}
}