package llm

import (
	"context"
	"encoding/json"
	"errors"
	"strings"
	"sync"
	"sync/atomic"
	"testing"
	"testing/fstest"
	"time"

	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
	"gitea.maximumdirect.net/eric/scriptorium"
)

func TestScriptoriumClientMapsPromptRequestAndUnmarshalsOutput(t *testing.T) {
	fake := &fakeScriptoriumLLM{content: `{"ok":true}`}
	client := newTestScriptoriumClient(t, fake)

	var out struct {
		OK bool `json:"ok"`
	}
	resp, err := client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		StageName:     "test-stage",
		PromptID:      "adapter.test",
		PromptVersion: "v1",
		ProfileID:     "explicit-profile",
		SessionID:     "session-123",
		Inputs: contracts.LLMInputSet{
			"transcript": contracts.NewLLMInputMaterial("transcript", "application/json", []byte(`{"source":true}`), "sha256:source", "file:///source.json"),
		},
		Vars: map[string]any{"custom": "value"},
	}, &out)
	if err != nil {
		t.Fatalf("CompleteStructured() error = %v, want nil", err)
	}
	if !out.OK {
		t.Fatalf("decoded output OK = false, want true")
	}
	if resp.Provider != scriptoriumProviderName || resp.Model != "explicit-model" || resp.ProfileID != "explicit-profile" {
		t.Fatalf("response metadata = %#v", resp)
	}
	if resp.PromptTokens != 11 || resp.CompletionTokens != 7 || resp.TotalTokens != 18 {
		t.Fatalf("usage = %#v, want mapped token counts", resp)
	}
	gotReq := fake.lastRequest()
	if gotReq.Prompt.SessionID != "session-123" {
		t.Fatalf("session id = %q, want session-123", gotReq.Prompt.SessionID)
	}
	if gotReq.Target.Model != "explicit-model" {
		t.Fatalf("model = %q, want explicit-model", gotReq.Target.Model)
	}
	if len(gotReq.Prompt.Messages) != 1 || !strings.Contains(gotReq.Prompt.Messages[0].Content, `{"source":true}`) {
		t.Fatalf("rendered messages = %#v, want transcript input content", gotReq.Prompt.Messages)
	}
	if gotReq.StructuredOutput == nil {
		t.Fatalf("structured output = nil, want JSON schema")
	}
	manifests := client.LLMProfileManifests()
	if len(manifests) != 1 || manifests[0].ID != "explicit-profile" || manifests[0].Model != "explicit-model" {
		t.Fatalf("profile manifests = %#v", manifests)
	}
}

func TestScriptoriumClientUsesPromptDefaultProfileWhenRequestProfileEmpty(t *testing.T) {
	fake := &fakeScriptoriumLLM{content: `{"ok":true}`}
	client := newTestScriptoriumClient(t, fake)

	var out map[string]any
	if _, err := client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		PromptID:  "adapter.test",
		SessionID: "session-123",
		Inputs: contracts.LLMInputSet{
			"transcript": contracts.NewLLMInputMaterial("transcript", "application/json", []byte(`{"source":true}`), "", ""),
		},
	}, &out); err != nil {
		t.Fatalf("CompleteStructured() error = %v, want nil", err)
	}
	if got := fake.lastRequest().Target.Model; got != "default-model" {
		t.Fatalf("model = %q, want prompt default profile model", got)
	}
}

func TestScriptoriumClientValidationFailureReturnsError(t *testing.T) {
	client := newTestScriptoriumClient(t, &fakeScriptoriumLLM{content: `{"bad":true}`})

	var out map[string]any
	_, err := client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		PromptID:  "adapter.test",
		SessionID: "session-123",
		Inputs: contracts.LLMInputSet{
			"transcript": contracts.NewLLMInputMaterial("transcript", "application/json", []byte(`{"source":true}`), "", ""),
		},
	}, &out)
	if err == nil || !strings.Contains(err.Error(), "validation failed") {
		t.Fatalf("CompleteStructured() error = %v, want validation failure", err)
	}
}

func TestScriptoriumClientProviderFailureIncludesContextAndRedactsBearerToken(t *testing.T) {
	client := newTestScriptoriumClient(t, &fakeScriptoriumLLM{err: errors.New("provider failed with Bearer secret-token")})

	var out map[string]any
	_, err := client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		PromptID:  "adapter.test",
		SessionID: "session-123",
		Inputs: contracts.LLMInputSet{
			"transcript": contracts.NewLLMInputMaterial("transcript", "application/json", []byte(`{"source":true}`), "", ""),
		},
	}, &out)
	if err == nil {
		t.Fatalf("CompleteStructured() error = nil, want provider error")
	}
	if !strings.Contains(err.Error(), `run Scriptorium prompt "adapter.test"`) {
		t.Fatalf("error = %q, want operation context", err.Error())
	}
	if strings.Contains(err.Error(), "secret-token") || !strings.Contains(err.Error(), "Bearer [REDACTED]") {
		t.Fatalf("error = %q, want redacted bearer token", err.Error())
	}
}

func TestScriptoriumClientContextCancellationIsRespected(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	client := newTestScriptoriumClient(t, &fakeScriptoriumLLM{content: `{"ok":true}`})

	var out map[string]any
	_, err := client.CompleteStructured(ctx, contracts.StructuredCompletionRequest{
		PromptID: "adapter.test",
		Inputs: contracts.LLMInputSet{
			"transcript": contracts.NewLLMInputMaterial("transcript", "application/json", []byte(`{"source":true}`), "", ""),
		},
	}, &out)
	if !errors.Is(err, context.Canceled) {
		t.Fatalf("CompleteStructured() error = %v, want context canceled", err)
	}
}

func TestScheduledScriptoriumClientBoundsConcurrentCalls(t *testing.T) {
	fake := &fakeScriptoriumLLM{
		content: `{"ok":true}`,
		block:   make(chan struct{}),
	}
	client := newTestScriptoriumClient(t, fake)
	scheduler, err := NewScheduler(1)
	if err != nil {
		t.Fatalf("NewScheduler() error = %v, want nil", err)
	}
	scheduled := NewScheduledClient(client, scheduler)

	var wg sync.WaitGroup
	for i := 0; i < 3; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			var out map[string]any
			_, callErr := scheduled.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
				PromptID:  "adapter.test",
				SessionID: "session-123",
				Inputs: contracts.LLMInputSet{
					"transcript": contracts.NewLLMInputMaterial("transcript", "application/json", []byte(`{"source":true}`), "", ""),
				},
			}, &out)
			if callErr != nil {
				t.Errorf("CompleteStructured() error = %v, want nil", callErr)
			}
		}()
	}
	waitForAtomicAtLeast(t, &fake.calls, 1)
	time.Sleep(20 * time.Millisecond)
	if got := atomic.LoadInt32(&fake.maxInFlight); got > 1 {
		t.Fatalf("max in-flight calls = %d, want <= 1", got)
	}
	close(fake.block)
	wg.Wait()
}

func TestScriptoriumClientValidatesRequest(t *testing.T) {
	client := newTestScriptoriumClient(t, &fakeScriptoriumLLM{content: `{"ok":true}`})
	var out map[string]any
	if _, err := client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{}, &out); err == nil || !strings.Contains(err.Error(), "prompt_id") {
		t.Fatalf("missing prompt id error = %v, want prompt_id validation", err)
	}
	if _, err := client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{PromptID: "adapter.test"}, nil); err == nil || !strings.Contains(err.Error(), "non-nil pointer") {
		t.Fatalf("nil output error = %v, want output validation", err)
	}
}

func newTestScriptoriumClient(t *testing.T, fake *fakeScriptoriumLLM) *ScriptoriumClient {
	t.Helper()
	registry := NewAssetRegistry()
	if err := registry.RegisterPromptFS(fstest.MapFS{
		"adapter.test.yaml": {Data: []byte(`id: adapter.test
version: "v1"
default_profile: default-profile
session_id: "{{ .session_id }}"
inputs:
  - name: transcript
    required: true
    content_type: application/json
messages:
  - role: user
    content: "Transcript: {{ input \"transcript\" }}"
output:
  format: json
  validation_mode: json_schema
  schema_path: adapter.schema.json
  repair_attempts: 0
`)},
	}, "."); err != nil {
		t.Fatalf("RegisterPromptFS() error = %v", err)
	}
	if err := registry.RegisterSchemaFS(fstest.MapFS{
		"adapter.schema.json": {Data: []byte(`{"type":"object","required":["ok"],"properties":{"ok":{"type":"boolean"}}}`)},
	}, "."); err != nil {
		t.Fatalf("RegisterSchemaFS() error = %v", err)
	}
	client, err := NewScriptoriumClient(ScriptoriumClientConfig{
		Assets: registry,
		EngineOptions: []scriptorium.Option{
			scriptorium.WithProfiles(
				scriptorium.OpenAICompatibleProfile(scriptorium.OpenAICompatibleProfileConfig{
					ID:       "default-profile",
					Endpoint: "http://127.0.0.1:1/v1",
					Model:    "default-model",
				}),
				scriptorium.OpenAICompatibleProfile(scriptorium.OpenAICompatibleProfileConfig{
					ID:       "explicit-profile",
					Endpoint: "http://127.0.0.1:1/v1",
					Model:    "explicit-model",
				}),
			),
			scriptorium.WithLLMClient(fake),
		},
	})
	if err != nil {
		t.Fatalf("NewScriptoriumClient() error = %v, want nil", err)
	}
	return client
}

type fakeScriptoriumLLM struct {
	content     string
	err         error
	block       chan struct{}
	mu          sync.Mutex
	last        scriptorium.GenerateRequest
	calls       int32
	inFlight    int32
	maxInFlight int32
}

func (f *fakeScriptoriumLLM) Generate(ctx context.Context, req scriptorium.GenerateRequest) (*scriptorium.GenerateResponse, error) {
	f.mu.Lock()
	f.last = req
	f.mu.Unlock()
	atomic.AddInt32(&f.calls, 1)
	current := atomic.AddInt32(&f.inFlight, 1)
	for {
		seen := atomic.LoadInt32(&f.maxInFlight)
		if current <= seen || atomic.CompareAndSwapInt32(&f.maxInFlight, seen, current) {
			break
		}
	}
	defer atomic.AddInt32(&f.inFlight, -1)
	if f.block != nil {
		select {
		case <-f.block:
		case <-ctx.Done():
			return nil, ctx.Err()
		}
	}
	if f.err != nil {
		return nil, f.err
	}
	content := f.content
	if content == "" {
		content = `{"ok":true}`
	}
	if !json.Valid([]byte(content)) {
		return nil, errors.New("test fake must return JSON content")
	}
	return &scriptorium.GenerateResponse{
		Content: content,
		Usage: scriptorium.TokenUsage{
			PromptTokens:     11,
			CompletionTokens: 7,
			TotalTokens:      18,
		},
	}, nil
}

func (f *fakeScriptoriumLLM) lastRequest() scriptorium.GenerateRequest {
	f.mu.Lock()
	defer f.mu.Unlock()
	return f.last
}