package openai

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"go-micro.dev/v6/ai"
)

func TestProvider_String(t *testing.T) {
	p := NewProvider()
	if p.String() != "openai" {
		t.Errorf("Expected provider name 'openai', got '%s'", p.String())
	}
}

func TestProvider_Init(t *testing.T) {
	p := NewProvider()

	err := p.Init(
		ai.WithModel("test-model"),
		ai.WithAPIKey("test-key"),
		ai.WithBaseURL("https://test.com"),
	)

	if err != nil {
		t.Fatalf("Init failed: %v", err)
	}

	opts := p.Options()
	if opts.Model != "test-model" {
		t.Errorf("Expected model 'test-model', got '%s'", opts.Model)
	}
	if opts.APIKey != "test-key" {
		t.Errorf("Expected API key 'test-key', got '%s'", opts.APIKey)
	}
	if opts.BaseURL != "https://test.com" {
		t.Errorf("Expected base URL 'https://test.com', got '%s'", opts.BaseURL)
	}
}

func TestProvider_Options(t *testing.T) {
	p := NewProvider(
		ai.WithModel("custom-model"),
		ai.WithAPIKey("my-key"),
	)

	opts := p.Options()
	if opts.Model != "custom-model" {
		t.Errorf("Expected model 'custom-model', got '%s'", opts.Model)
	}
	if opts.APIKey != "my-key" {
		t.Errorf("Expected API key 'my-key', got '%s'", opts.APIKey)
	}
}

func TestProvider_Defaults(t *testing.T) {
	p := NewProvider()

	opts := p.Options()
	if opts.Model != "gpt-4o" {
		t.Errorf("Expected default model 'gpt-4o', got '%s'", opts.Model)
	}
	if opts.BaseURL != "https://api.openai.com" {
		t.Errorf("Expected default base URL 'https://api.openai.com', got '%s'", opts.BaseURL)
	}
}

func TestProvider_Generate_NoAPIKey(t *testing.T) {
	p := NewProvider()

	req := &ai.Request{
		Prompt:       "Hello",
		SystemPrompt: "You are helpful",
	}

	_, err := p.Generate(context.Background(), req)
	if err == nil {
		t.Error("Expected error when API key is missing, got nil")
	}
}

func TestProvider_Stream(t *testing.T) {
	var sawStream bool
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/v1/chat/completions" {
			t.Fatalf("path = %s, want /v1/chat/completions", r.URL.Path)
		}
		var body map[string]any
		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
			t.Fatalf("decode request: %v", err)
		}
		sawStream, _ = body["stream"].(bool)
		w.Header().Set("Content-Type", "text/event-stream")
		_, _ = w.Write([]byte("data: {\"choices\":[{\"delta\":{\"content\":\"hel\"}}]}\n\n"))
		_, _ = w.Write([]byte("data: {\"choices\":[{\"delta\":{\"content\":\"lo\"}}]}\n\n"))
		_, _ = w.Write([]byte("data: [DONE]\n\n"))
	}))
	defer ts.Close()

	p := NewProvider(ai.WithAPIKey("test-key"), ai.WithBaseURL(ts.URL))
	stream, err := p.Stream(context.Background(), &ai.Request{Prompt: "Hello"})
	if err != nil {
		t.Fatalf("Stream returned error: %v", err)
	}
	defer stream.Close()
	if !sawStream {
		t.Fatal("stream request did not set stream=true")
	}

	first, err := stream.Recv()
	if err != nil || first.Reply != "hel" {
		t.Fatalf("first chunk = %#v, %v; want hel", first, err)
	}
	second, err := stream.Recv()
	if err != nil || second.Reply != "lo" {
		t.Fatalf("second chunk = %#v, %v; want lo", second, err)
	}
	if _, err := stream.Recv(); !errors.Is(err, io.EOF) {
		t.Fatalf("final error = %v, want EOF", err)
	}
}

func TestProvider_StreamPropagatesMalformedChunk(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "text/event-stream")
		_, _ = w.Write([]byte("data: {bad json}\n\n"))
	}))
	defer ts.Close()

	p := NewProvider(ai.WithAPIKey("test-key"), ai.WithBaseURL(ts.URL))
	stream, err := p.Stream(context.Background(), &ai.Request{Prompt: "Hello"})
	if err != nil {
		t.Fatalf("Stream returned error: %v", err)
	}
	defer stream.Close()

	if _, err := stream.Recv(); err == nil {
		t.Fatal("Recv returned nil error for malformed chunk")
	}
}

func TestProvider_StreamCloseReleasesResponse(t *testing.T) {
	released := make(chan struct{})
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "text/event-stream")
		_, _ = w.Write([]byte("data: {\"choices\":[{\"delta\":{\"content\":\"hel\"}}]}\n\n"))
		if f, ok := w.(http.Flusher); ok {
			f.Flush()
		}
		<-r.Context().Done()
		close(released)
	}))
	defer ts.Close()

	p := NewProvider(ai.WithAPIKey("test-key"), ai.WithBaseURL(ts.URL))
	stream, err := p.Stream(context.Background(), &ai.Request{Prompt: "Hello"})
	if err != nil {
		t.Fatalf("Stream returned error: %v", err)
	}
	first, err := stream.Recv()
	if err != nil || first.Reply != "hel" {
		t.Fatalf("first chunk = %#v, %v; want hel", first, err)
	}
	if err := stream.Close(); err != nil {
		t.Fatalf("Close returned error: %v", err)
	}

	select {
	case <-released:
	case <-time.After(time.Second):
		t.Fatal("server did not observe closed stream request")
	}
}

func TestProvider_ImageRegistration(t *testing.T) {
	ig := ai.NewImage("openai", ai.WithAPIKey("test"))
	if ig == nil {
		t.Fatal("ai.NewImage('openai') returned nil — image provider not registered")
	}
	if ig.String() != "openai" {
		t.Errorf("Expected 'openai', got '%s'", ig.String())
	}
}

func TestProvider_GenerateImage_NoAPIKey(t *testing.T) {
	p := NewProvider()
	_, err := p.GenerateImage(context.Background(), &ai.ImageRequest{Prompt: "a cat"})
	if err == nil {
		t.Error("Expected error when API key is missing, got nil")
	}
}

func TestProvider_ImplementsImageModel(t *testing.T) {
	var _ ai.ImageModel = (*Provider)(nil)
}
