package promptkit_test

import (
	"context"
	"errors"
	"sync"
	"testing"

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

func TestWithNamespacesRoutesOrdinarySelectionsAndPreservesViews(t *testing.T) {
	client := &fakeLLMClient{response: &promptkit.GenerateResponse{Content: "reply"}}
	engine := newNamespacedContractEngine(t, client)
	alpha, err := engine.WithNamespaces(promptkit.Namespaces{Prompt: "alpha", Profile: "alpha"})
	if err != nil {
		t.Fatal(err)
	}
	beta, err := engine.WithNamespaces(promptkit.Namespaces{Prompt: "beta", Profile: "beta"})
	if err != nil {
		t.Fatal(err)
	}

	request := promptkit.RunRequest{PromptID: "shared", ProfileID: "shared"}
	prepared, err := alpha.Prepare(context.Background(), request)
	if err != nil {
		t.Fatalf("prepare scoped request: %v", err)
	}
	assertNamespacedSelection(t, prepared.PromptID, prepared.SelectedProfileID, prepared.SelectedBackendID, "alpha")

	betaPrepared, err := beta.Prepare(context.Background(), request)
	if err != nil {
		t.Fatalf("prepare independent view: %v", err)
	}
	assertNamespacedSelection(t, betaPrepared.PromptID, betaPrepared.SelectedProfileID, betaPrepared.SelectedBackendID, "beta")
	if err := alpha.ValidateRequest(context.Background(), request); err != nil {
		t.Fatalf("validate scoped request: %v", err)
	}

	qualified, err := alpha.Prepare(context.Background(), promptkit.RunRequest{PromptID: "beta/shared", ProfileID: "beta/shared"})
	if err != nil {
		t.Fatalf("prepare qualified bypass: %v", err)
	}
	assertNamespacedSelection(t, qualified.PromptID, qualified.SelectedProfileID, qualified.SelectedBackendID, "beta")

	preparedExecution, err := alpha.PrepareExecution(context.Background(), request)
	if err != nil {
		t.Fatalf("prepare execution: %v", err)
	}
	details := preparedExecution.Details()
	assertNamespacedSelection(t, details.PromptID, details.SelectedProfileID, details.SelectedBackendID, "alpha")
	// A handle captures its qualified selection and remains runnable through the
	// original facade because the views share the same assembled runner.
	result, err := engine.RunPrepared(context.Background(), preparedExecution)
	if err != nil {
		t.Fatalf("run scoped prepared handle through original view: %v", err)
	}
	assertNamespacedSelection(t, result.PromptID, result.SelectedProfileID, result.SelectedBackendID, "alpha")

	var events []promptkit.ExecutionEvent
	runResult, err := alpha.Run(context.Background(), promptkit.RunRequest{
		PromptID: "shared", ProfileID: "shared",
		Observer: func(event promptkit.ExecutionEvent) { events = append(events, event) },
	})
	if err != nil {
		t.Fatalf("run scoped request: %v", err)
	}
	assertNamespacedSelection(t, runResult.PromptID, runResult.SelectedProfileID, runResult.SelectedBackendID, "alpha")
	var sawScopedEvent bool
	for _, event := range events {
		if event.PromptID == "alpha/shared" && event.ProfileID == "alpha/shared" && event.BackendID == "alpha/backend" {
			sawScopedEvent = true
		}
	}
	if !sawScopedEvent {
		t.Fatalf("observer events did not retain qualified identities: %+v", events)
	}

	// The original engine remains unscoped and can still select the exact IDs.
	original, err := engine.Prepare(context.Background(), promptkit.RunRequest{PromptID: "root-only", ProfileID: "root-only"})
	if err != nil {
		t.Fatalf("original engine was changed by scoped views: %v", err)
	}
	if original.PromptID != "root-only" || original.SelectedProfileID != "root-only" || original.EffectiveModelParams.Model != "root-model" {
		t.Fatalf("original engine selection = %+v, want unqualified root resources", original)
	}
}

func TestWithNamespacesHasNoFallbackAndValidatesAtTheCorrectBoundary(t *testing.T) {
	engine := newNamespacedContractEngine(t, &fakeLLMClient{response: &promptkit.GenerateResponse{Content: "reply"}})
	scoped, err := engine.WithNamespaces(promptkit.Namespaces{Prompt: "alpha", Profile: "alpha"})
	if err != nil {
		t.Fatal(err)
	}
	if _, err := scoped.Prepare(context.Background(), promptkit.RunRequest{PromptID: "root-only", ProfileID: "alpha/shared"}); !errors.Is(err, promptkit.ErrPromptNotFound) {
		t.Fatalf("root prompt fallback error = %v, want ErrPromptNotFound", err)
	}
	if _, err := scoped.Prepare(context.Background(), promptkit.RunRequest{PromptID: "alpha/shared", ProfileID: "root-only"}); !errors.Is(err, promptkit.ErrProfileNotFound) {
		t.Fatalf("root profile fallback error = %v, want ErrProfileNotFound", err)
	}
	unknown, err := engine.WithNamespaces(promptkit.Namespaces{Prompt: "not-configured"})
	if err != nil {
		t.Fatalf("well-formed absent namespace rejected at view creation: %v", err)
	}
	if _, err := unknown.Prepare(context.Background(), promptkit.RunRequest{PromptID: "root-only", ProfileID: "alpha/shared"}); !errors.Is(err, promptkit.ErrPromptNotFound) {
		t.Fatalf("selection from absent namespace error = %v, want ErrPromptNotFound", err)
	}
	if _, err := scoped.Prepare(context.Background(), promptkit.RunRequest{PromptID: "alpha/beta/gamma", ProfileID: "alpha/shared"}); !errors.Is(err, promptkit.ErrInvalidRequest) {
		t.Fatalf("malformed caller prompt ID error = %v, want ErrInvalidRequest", err)
	}
	for _, invalid := range []promptkit.Namespaces{
		{Prompt: "alpha/beta"},
		{Profile: "/alpha"},
		{Backend: "  "},
	} {
		if _, err := engine.WithNamespaces(invalid); !errors.Is(err, promptkit.ErrInvalidConfig) {
			t.Errorf("invalid namespaces %+v error = %v, want ErrInvalidConfig", invalid, err)
		}
	}
	if _, err := (*promptkit.Engine)(nil).WithNamespaces(promptkit.Namespaces{}); !errors.Is(err, promptkit.ErrInvalidConfig) {
		t.Fatalf("nil engine error = %v, want ErrInvalidConfig", err)
	}
	cleared, err := scoped.WithNamespaces(promptkit.Namespaces{})
	if err != nil {
		t.Fatal(err)
	}
	if _, err := cleared.Prepare(context.Background(), promptkit.RunRequest{PromptID: "shared", ProfileID: "alpha/shared"}); !errors.Is(err, promptkit.ErrPromptNotFound) {
		t.Fatalf("cleared view unexpectedly retained prior scope: %v", err)
	}
	if _, err := scoped.Prepare(context.Background(), promptkit.RunRequest{PromptID: "shared", ProfileID: "shared"}); err != nil {
		t.Fatalf("replacing scopes mutated the prior view: %v", err)
	}
}

func TestWithNamespacesViewsCanPrepareConcurrently(t *testing.T) {
	engine := newNamespacedContractEngine(t, &fakeLLMClient{response: &promptkit.GenerateResponse{Content: "reply"}})
	alpha, err := engine.WithNamespaces(promptkit.Namespaces{Prompt: "alpha", Profile: "alpha"})
	if err != nil {
		t.Fatal(err)
	}
	beta, err := engine.WithNamespaces(promptkit.Namespaces{Prompt: "beta", Profile: "beta"})
	if err != nil {
		t.Fatal(err)
	}
	var wait sync.WaitGroup
	for _, view := range []*promptkit.Engine{alpha, beta} {
		view := view
		wait.Add(1)
		go func() {
			defer wait.Done()
			prepared, err := view.Prepare(context.Background(), promptkit.RunRequest{PromptID: "shared", ProfileID: "shared"})
			if err != nil {
				t.Errorf("concurrent prepare: %v", err)
				return
			}
			want := "alpha"
			if view == beta {
				want = "beta"
			}
			assertNamespacedSelection(t, prepared.PromptID, prepared.SelectedProfileID, prepared.SelectedBackendID, want)
		}()
	}
	wait.Wait()
}

func TestWithNamespacesRoutesInspectionsAndSmokeSelections(t *testing.T) {
	engine := newNamespacedContractEngine(t, &fakeLLMClient{response: &promptkit.GenerateResponse{Content: "reply"}})
	scoped, err := engine.WithNamespaces(promptkit.Namespaces{
		Prompt: "alpha", Profile: "beta", Backend: "alpha",
	})
	if err != nil {
		t.Fatal(err)
	}

	prompt, err := scoped.InspectPrompt(context.Background(), "shared")
	if err != nil || prompt.PromptID != "alpha/shared" {
		t.Fatalf("scoped prompt inspection = %+v, error %v", prompt, err)
	}
	profile, err := scoped.InspectProfile(context.Background(), "shared")
	if err != nil || profile.ProfileID != "beta/shared" {
		t.Fatalf("scoped profile inspection = %+v, error %v", profile, err)
	}
	requirements, err := scoped.InspectRequirements(context.Background(), promptkit.RequirementInspectionRequest{
		PromptID: "shared", ProfileID: "shared",
	})
	if err != nil || requirements.PromptID != "alpha/shared" || requirements.ProfileID != "beta/shared" {
		t.Fatalf("scoped requirements inspection = %+v, error %v", requirements, err)
	}
	qualifiedPrompt, err := scoped.InspectPrompt(context.Background(), "beta/shared")
	if err != nil || qualifiedPrompt.PromptID != "beta/shared" {
		t.Fatalf("qualified prompt inspection = %+v, error %v", qualifiedPrompt, err)
	}

	// Explicit profile selection keeps precedence over the supplied backend,
	// while prompt, profile, and backend caller references are independently
	// validated/qualified. The profile's configured backend remains exact.
	report, err := scoped.SmokeTest(context.Background(), promptkit.SmokeTestRequest{
		Kind: promptkit.SmokeTestReachability, PromptID: "shared", ProfileID: "shared", BackendID: "backend",
	})
	if err != nil {
		t.Fatal(err)
	}
	if report.Target.PromptID != "alpha/shared" || report.Target.ProfileID != "beta/shared" ||
		report.Target.BackendID != "beta/backend" || report.Target.SelectionSource != "profile" {
		t.Fatalf("scoped smoke selection = %+v", report.Target)
	}
	backendReport, err := scoped.SmokeTest(context.Background(), promptkit.SmokeTestRequest{
		Kind: promptkit.SmokeTestReachability, BackendID: "backend",
	})
	if err != nil {
		t.Fatal(err)
	}
	if backendReport.Target.BackendID != "alpha/backend" || backendReport.Target.SelectionSource != "backend" {
		t.Fatalf("scoped backend diagnostic selection = %+v", backendReport.Target)
	}
	defaultedReport, err := scoped.SmokeTest(context.Background(), promptkit.SmokeTestRequest{
		Kind: promptkit.SmokeTestReachability, PromptID: "shared",
	})
	if err != nil {
		t.Fatal(err)
	}
	if defaultedReport.Target.PromptID != "alpha/shared" || defaultedReport.Target.ProfileID != "root-only" ||
		defaultedReport.Target.SelectionSource != "prompt" {
		t.Fatalf("configured prompt default was rewritten by scope: %+v", defaultedReport.Target)
	}

	for _, run := range []func() error{
		func() error { _, err := scoped.InspectPrompt(context.Background(), "alpha/beta/shared"); return err },
		func() error { _, err := scoped.InspectProfile(context.Background(), "alpha/beta/shared"); return err },
		func() error {
			_, err := scoped.InspectRequirements(context.Background(), promptkit.RequirementInspectionRequest{
				PromptID: "alpha/beta/shared", ProfileID: "shared",
			})
			return err
		},
		func() error {
			_, err := scoped.SmokeTest(context.Background(), promptkit.SmokeTestRequest{
				Kind: promptkit.SmokeTestReachability, PromptID: "alpha/beta/shared",
			})
			return err
		},
		func() error {
			_, err := scoped.SmokeTest(context.Background(), promptkit.SmokeTestRequest{
				Kind: promptkit.SmokeTestReachability, ProfileID: "alpha/beta/shared",
			})
			return err
		},
		func() error {
			_, err := scoped.SmokeTest(context.Background(), promptkit.SmokeTestRequest{
				Kind: promptkit.SmokeTestReachability, ProfileID: "shared", BackendID: "alpha/beta/backend",
			})
			return err
		},
	} {
		if err := run(); !errors.Is(err, promptkit.ErrInvalidRequest) {
			t.Errorf("malformed supplied ID error = %v, want ErrInvalidRequest", err)
		}
	}
	if _, err := scoped.InspectPrompt(context.Background(), "missing"); !errors.Is(err, promptkit.ErrPromptNotFound) {
		t.Errorf("well-formed missing prompt error = %v, want ErrPromptNotFound", err)
	}
}

func newNamespacedContractEngine(t *testing.T, client promptkit.LLMClient) *promptkit.Engine {
	t.Helper()
	var inputs []configkit.Input
	for _, namespace := range []string{"alpha", "beta"} {
		endpoint := "https://" + namespace + ".example/v1"
		input, err := promptkit.CollectionInput(namespace, configkit.Mapping(namespace+" resources", map[string]any{
			"backends": map[string]any{"backend": map[string]any{"endpoint": endpoint}},
			"profiles": map[string]any{"shared": map[string]any{
				"backend": namespace + "/backend", "model": namespace + "-model",
			}},
			"prompts": map[string]any{"shared": map[string]any{
				"version":         "1",
				"default_profile": "root-only",
				"messages":        []any{map[string]any{"role": "user", "content": "Hello"}},
				"output":          map[string]any{"format": "text", "validation_mode": "none"},
			}},
		}))
		if err != nil {
			t.Fatal(err)
		}
		input.Imports = false
		inputs = append(inputs, input)
	}
	inputs = append(inputs, configkit.Input{Source: configkit.Mapping("root resources", map[string]any{
		"profiles": map[string]any{"root-only": map[string]any{
			"endpoint": "https://root.example/v1", "model": "root-model",
		}},
		"prompts": map[string]any{"root-only": map[string]any{
			"version":  "1",
			"messages": []any{map[string]any{"role": "user", "content": "Root prompt"}},
			"output":   map[string]any{"format": "text", "validation_mode": "none"},
		}},
	})})
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
		Underlays: []configkit.Underlay{{Inputs: inputs}},
	}}, promptkit.WithLLMClient(client))
	if err != nil {
		var loadErr *configkit.LoadError
		if errors.As(err, &loadErr) {
			t.Fatalf("construct namespaced engine: %v: %+v", err, loadErr.Diagnostics())
		}
		t.Fatalf("construct namespaced engine: %v", err)
	}
	return engine
}

func assertNamespacedSelection(t *testing.T, promptID, profileID, backendID, namespace string) {
	t.Helper()
	if promptID != namespace+"/shared" || profileID != namespace+"/shared" || backendID != namespace+"/backend" {
		t.Fatalf("selected IDs = (%q, %q, %q), want namespace %q", promptID, profileID, backendID, namespace)
	}
}