package server

import (
	"encoding/json"
	"net/http/httptest"
	"strings"
	"testing"

	"github.com/daniel/cursor-adapter/internal/types"
)

func TestNewSSEWriter(t *testing.T) {
	rec := httptest.NewRecorder()
	sse := NewSSEWriter(rec)
	if sse == nil {
		t.Fatal("NewSSEWriter returned nil")
	}
	headers := rec.Header()
	if got := headers.Get("Content-Type"); got != "text/event-stream" {
		t.Errorf("Content-Type = %q, want %q", got, "text/event-stream")
	}
	if got := headers.Get("Cache-Control"); got != "no-cache" {
		t.Errorf("Cache-Control = %q, want %q", got, "no-cache")
	}
	if got := headers.Get("Connection"); got != "keep-alive" {
		t.Errorf("Connection = %q, want %q", got, "keep-alive")
	}
	if got := headers.Get("X-Accel-Buffering"); got != "no" {
		t.Errorf("X-Accel-Buffering = %q, want %q", got, "no")
	}
}

func TestWriteChunk(t *testing.T) {
	rec := httptest.NewRecorder()
	sse := NewSSEWriter(rec)

	content := "hello"
	chunk := types.NewChatCompletionChunk("test-id", 0, "", types.Delta{Content: &content})

	if err := sse.WriteChunk(chunk); err != nil {
		t.Fatalf("WriteChunk returned error: %v", err)
	}

	body := rec.Body.String()
	if !strings.HasPrefix(body, "data: ") {
		t.Errorf("WriteChunk output missing 'data: ' prefix, got %q", body)
	}
	if !strings.HasSuffix(body, "\n\n") {
		t.Errorf("WriteChunk output missing trailing newlines, got %q", body)
	}

	jsonStr := strings.TrimPrefix(body, "data: ")
	jsonStr = strings.TrimSuffix(jsonStr, "\n\n")
	var parsed types.ChatCompletionChunk
	if err := json.Unmarshal([]byte(jsonStr), &parsed); err != nil {
		t.Fatalf("failed to unmarshal chunk JSON: %v", err)
	}
	if parsed.ID != "test-id" {
		t.Errorf("parsed chunk ID = %q, want %q", parsed.ID, "test-id")
	}
	if len(parsed.Choices) != 1 || *parsed.Choices[0].Delta.Content != "hello" {
		t.Errorf("parsed chunk content mismatch, got %v", parsed)
	}
}

func TestWriteDone(t *testing.T) {
	rec := httptest.NewRecorder()
	sse := NewSSEWriter(rec)

	sse.WriteDone()

	body := rec.Body.String()
	want := "data: [DONE]\n\n"
	if body != want {
		t.Errorf("WriteDone output = %q, want %q", body, want)
	}
}