package llm

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"sync/atomic"
	"testing"
	"time"

	"gitea.maximumdirect.net/eric/audita/internal/framework/contracts"
	"gitea.maximumdirect.net/eric/audita/internal/framework/responseschema"
)

func TestNewOpenAICompatibleClientValidation(t *testing.T) {
	_, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL: " ",
		Model:   "model",
	})
	if err == nil || !strings.Contains(err.Error(), "base URL") {
		t.Fatalf("expected base URL validation error, got %v", err)
	}

	_, err = NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL: "https://example.test/v1",
		Model:   " ",
	})
	if err == nil || !strings.Contains(err.Error(), "model") {
		t.Fatalf("expected model validation error, got %v", err)
	}

	_, err = NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL:    "https://example.test/v1",
		Model:      "model",
		MaxRetries: -1,
	})
	if err == nil || !strings.Contains(err.Error(), "max retries") {
		t.Fatalf("expected max retries validation error, got %v", err)
	}
}

func TestOpenAICompatibleClientRequestShapeAndDecode(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	var seenPath string
	var seenAuthorization string
	var seenReq map[string]any
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		seenPath = r.URL.Path
		seenAuthorization = r.Header.Get("Authorization")
		if err := json.NewDecoder(r.Body).Decode(&seenReq); err != nil {
			t.Fatalf("decode request: %v", err)
		}

		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
  "model":"provider-model",
  "choices":[{"message":{"content":"{\"name\":\"Robby\",\"age\":22}"}}],
  "usage":{"prompt_tokens":11,"completion_tokens":7,"total_tokens":18}
}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL:    server.URL + "/v1",
		Model:      "test-model",
		APIKey:     "secret-key",
		MaxRetries: 1,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	type person struct {
		Name string `json:"name"`
		Age  int    `json:"age"`
	}
	var out person
	resp, err := client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err != nil {
		t.Fatalf("CompleteStructured: %v", err)
	}

	if seenPath != "/v1/chat/completions" {
		t.Fatalf("unexpected request path: %q", seenPath)
	}
	if seenAuthorization != "Bearer secret-key" {
		t.Fatalf("unexpected authorization header: %q", seenAuthorization)
	}

	responseFormat, ok := seenReq["response_format"].(map[string]any)
	if !ok {
		t.Fatalf("expected response_format object, got %T", seenReq["response_format"])
	}
	if responseFormat["type"] != "json_schema" {
		t.Fatalf("unexpected response_format.type: %v", responseFormat["type"])
	}
	jsonSchema, ok := responseFormat["json_schema"].(map[string]any)
	if !ok {
		t.Fatalf("expected response_format.json_schema object, got %T", responseFormat["json_schema"])
	}
	if jsonSchema["name"] != schema.Name {
		t.Fatalf("unexpected response schema name: %v", jsonSchema["name"])
	}
	if jsonSchema["strict"] != true {
		t.Fatalf("expected strict=true, got %v", jsonSchema["strict"])
	}
	if _, ok := jsonSchema["schema"].(map[string]any); !ok {
		t.Fatalf("expected embedded JSON schema object, got %T", jsonSchema["schema"])
	}

	if out.Name != "Robby" || out.Age != 22 {
		t.Fatalf("unexpected decoded output: %+v", out)
	}
	if resp.Provider != "openai-compatible" {
		t.Fatalf("unexpected provider metadata: %q", resp.Provider)
	}
	if resp.Model != "provider-model" {
		t.Fatalf("unexpected model metadata: %q", resp.Model)
	}
	if resp.PromptTokens != 11 || resp.CompletionTokens != 7 || resp.TotalTokens != 18 {
		t.Fatalf("unexpected token metadata: %+v", resp)
	}
}

func TestOpenAICompatibleClientDecodesCorrectionSetStructuredResponse(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
  "choices":[{"message":{"content":"{\"corrections\":[{\"id\":1,\"original_text\":\"teh\",\"corrected_text\":\"the\",\"confidence\":0.9}]}"}}]
}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL: server.URL,
		Model:   "test-model",
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	type correction struct {
		TargetSegmentID int     `json:"id"`
		OriginalText    string  `json:"original_text"`
		CorrectedText   string  `json:"corrected_text"`
		Confidence      float64 `json:"confidence"`
	}
	type correctionSet struct {
		Corrections []correction `json:"corrections"`
	}
	var out correctionSet
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err != nil {
		t.Fatalf("CompleteStructured: %v", err)
	}
	if len(out.Corrections) != 1 {
		t.Fatalf("expected one correction, got %+v", out.Corrections)
	}
	if out.Corrections[0].TargetSegmentID != 1 || out.Corrections[0].CorrectedText != "the" {
		t.Fatalf("unexpected correction payload: %+v", out.Corrections[0])
	}
}

func TestOpenAICompatibleClientDecodesValidatorDecisionSetStructuredResponse(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.ValidatorDecisionSetKey)
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
  "choices":[{"message":{"content":"{\"validations\":[{\"correction_index\":0,\"approved\":true,\"confidence\":0.95,\"reason\":\"ok\"}]}"}}]
}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL: server.URL,
		Model:   "test-model",
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	type validationDecision struct {
		CorrectionIndex int     `json:"correction_index"`
		Approved        bool    `json:"approved"`
		Confidence      float64 `json:"confidence"`
		Reason          string  `json:"reason"`
	}
	type validationResponse struct {
		Validations []validationDecision `json:"validations"`
	}
	var out validationResponse
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err != nil {
		t.Fatalf("CompleteStructured: %v", err)
	}
	if len(out.Validations) != 1 {
		t.Fatalf("expected one validation decision, got %+v", out.Validations)
	}
	if out.Validations[0].CorrectionIndex != 0 || !out.Validations[0].Approved {
		t.Fatalf("unexpected validation payload: %+v", out.Validations[0])
	}
}

func TestOpenAICompatibleClientNoAuthorizationHeaderWithoutAPIKey(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	var seenAuthorization string
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		seenAuthorization = r.Header.Get("Authorization")
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"choices":[{"message":{"content":"{\"ok\":true}"}}]}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL: server.URL,
		Model:   "test-model",
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	var out map[string]any
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err != nil {
		t.Fatalf("CompleteStructured: %v", err)
	}
	if seenAuthorization != "" {
		t.Fatalf("expected empty Authorization header, got %q", seenAuthorization)
	}
}

func TestOpenAICompatibleClientMalformedJSONFailsSafely(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"choices":[{"message":{"content":"{"}}]}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL:    server.URL,
		Model:      "test-model",
		MaxRetries: 0,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	var out map[string]any
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err == nil || !strings.Contains(err.Error(), "decode structured output") {
		t.Fatalf("expected decode error, got %v", err)
	}
}

func TestOpenAICompatibleClientMissingRequiredFieldsFailsSafely(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"model":"x","choices":[]}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL:    server.URL,
		Model:      "test-model",
		MaxRetries: 0,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	var out map[string]any
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err == nil || !strings.Contains(err.Error(), "missing choices") {
		t.Fatalf("expected missing-field error, got %v", err)
	}
}

func TestOpenAICompatibleClientUnknownExtraFieldsFollowLocalDecoderPolicy(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
  "choices":[{"message":{"content":"{\"corrections\":[{\"id\":1,\"original_text\":\"teh\",\"corrected_text\":\"the\",\"confidence\":0.9,\"extra\":\"ignored\"}],\"top_extra\":true}"}}]
}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL: server.URL,
		Model:   "test-model",
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	type correction struct {
		TargetSegmentID int     `json:"id"`
		OriginalText    string  `json:"original_text"`
		CorrectedText   string  `json:"corrected_text"`
		Confidence      float64 `json:"confidence"`
	}
	type correctionSet struct {
		Corrections []correction `json:"corrections"`
	}
	var out correctionSet
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err != nil {
		t.Fatalf("expected unknown extra fields to be ignored by local decoder, got %v", err)
	}
	if len(out.Corrections) != 1 || out.Corrections[0].CorrectedText != "the" {
		t.Fatalf("unexpected decoded payload: %+v", out.Corrections)
	}
}

func TestOpenAICompatibleClientProviderErrorRedactsSecret(t *testing.T) {
	secret := "super-secret-key"
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusUnauthorized)
		_, _ = w.Write([]byte(`{"error":{"message":"Authorization failed for Bearer super-secret-key"}}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL: server.URL,
		Model:   "test-model",
		APIKey:  secret,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	var out map[string]any
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err == nil {
		t.Fatalf("expected provider error")
	}
	if strings.Contains(err.Error(), secret) {
		t.Fatalf("error leaked secret: %v", err)
	}
	if !strings.Contains(err.Error(), "[REDACTED]") {
		t.Fatalf("expected redaction marker in error: %v", err)
	}
}

func TestOpenAICompatibleClientRequestErrorRedactsSecret(t *testing.T) {
	secret := "super-secret-key"
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL: "https://example.test/v1",
		Model:   "test-model",
		APIKey:  secret,
		HTTPClient: &http.Client{
			Transport: roundTripFunc(func(r *http.Request) (*http.Response, error) {
				_ = r
				return nil, fmt.Errorf("request failed for Authorization: Bearer %s", secret)
			}),
		},
		MaxRetries: 0,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	var out map[string]any
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err == nil {
		t.Fatalf("expected request error")
	}
	if strings.Contains(err.Error(), secret) {
		t.Fatalf("error leaked secret: %v", err)
	}
	if !strings.Contains(err.Error(), "[REDACTED]") {
		t.Fatalf("expected redaction marker in error: %v", err)
	}
}

func TestOpenAICompatibleClientCancellationAndTimeout(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		select {
		case <-r.Context().Done():
			return
		case <-time.After(200 * time.Millisecond):
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"choices":[{"message":{"content":"{\"ok\":true}"}}]}`))
		}
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL:        server.URL,
		Model:          "test-model",
		RequestTimeout: 20 * time.Millisecond,
		MaxRetries:     0,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	var out map[string]any
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err == nil {
		t.Fatalf("expected timeout-related error")
	}
	if !strings.Contains(strings.ToLower(err.Error()), "context deadline") {
		t.Fatalf("expected context deadline in error, got %v", err)
	}
}

func TestOpenAICompatibleClientRetryBehavior(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	var attempts int32
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		current := atomic.AddInt32(&attempts, 1)
		if current == 1 {
			w.WriteHeader(http.StatusInternalServerError)
			_, _ = w.Write([]byte(`{"error":{"message":"temporary failure"}}`))
			return
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"choices":[{"message":{"content":"{\"ok\":true}"}}]}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL:    server.URL,
		Model:      "test-model",
		MaxRetries: 1,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	var out map[string]any
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err != nil {
		t.Fatalf("CompleteStructured: %v", err)
	}
	if atomic.LoadInt32(&attempts) != 2 {
		t.Fatalf("expected 2 attempts, got %d", attempts)
	}
}

func TestOpenAICompatibleClientRetryOnMalformedStructuredOutput(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	var attempts int32
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		current := atomic.AddInt32(&attempts, 1)
		w.Header().Set("Content-Type", "application/json")
		if current == 1 {
			_, _ = w.Write([]byte(`{"choices":[{"message":{"content":"{"}}]}`))
			return
		}
		_, _ = w.Write([]byte(`{"choices":[{"message":{"content":"{\"ok\":true}"}}]}`))
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL:    server.URL,
		Model:      "test-model",
		MaxRetries: 1,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	var out map[string]any
	_, err = client.CompleteStructured(context.Background(), contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err != nil {
		t.Fatalf("CompleteStructured: %v", err)
	}
	if atomic.LoadInt32(&attempts) != 2 {
		t.Fatalf("expected 2 attempts, got %d", attempts)
	}
}

func TestOpenAICompatibleClientHonorsCancelledContextWithoutRetry(t *testing.T) {
	schema := responseschema.MustLookup(responseschema.CorrectionSetKey)
	var attempts int32
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		atomic.AddInt32(&attempts, 1)
		<-r.Context().Done()
	}))
	defer server.Close()

	client, err := NewOpenAICompatibleClient(OpenAICompatibleClientConfig{
		BaseURL:    server.URL,
		Model:      "test-model",
		MaxRetries: 3,
	})
	if err != nil {
		t.Fatalf("NewOpenAICompatibleClient: %v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	cancel()

	var out map[string]any
	_, err = client.CompleteStructured(ctx, contracts.StructuredCompletionRequest{
		Messages:       []contracts.LLMMessage{{Role: "user", Content: "extract"}},
		ResponseSchema: &schema,
	}, &out)
	if err == nil {
		t.Fatalf("expected cancellation error")
	}
	if !errors.Is(err, context.Canceled) && !strings.Contains(strings.ToLower(err.Error()), "canceled") {
		t.Fatalf("expected cancellation-related error, got %v", err)
	}
	if atomic.LoadInt32(&attempts) > 1 {
		t.Fatalf("expected no retry after cancellation, got attempts=%d", attempts)
	}
}

type roundTripFunc func(*http.Request) (*http.Response, error)

func (f roundTripFunc) RoundTrip(r *http.Request) (*http.Response, error) {
	return f(r)
}

func newJSONHTTPResponse(status int, body string) *http.Response {
	return &http.Response{
		StatusCode: status,
		Header:     http.Header{"Content-Type": []string{"application/json"}},
		Body:       io.NopCloser(strings.NewReader(body)),
	}
}