package llm

import (
	"encoding/base64"
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// 1x1 红色 PNG
const tinyPNG = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg=="

func writeTinyPNG(t *testing.T) string {
	t.Helper()
	data, _ := base64.StdEncoding.DecodeString(tinyPNG)
	path := filepath.Join(t.TempDir(), "shot.png")
	if err := os.WriteFile(path, data, 0o644); err != nil {
		t.Fatal(err)
	}
	return path
}

func TestLoadImage(t *testing.T) {
	path := writeTinyPNG(t)
	b64, mt, err := LoadImage(path)
	if err != nil {
		t.Fatal(err)
	}
	if mt != "image/png" || b64 != tinyPNG {
		t.Fatalf("roundtrip failed: mt=%s len=%d", mt, len(b64))
	}
	if _, _, err := LoadImage("x.txt"); err == nil {
		t.Fatal("expected unsupported type error")
	}
}

func TestOpenAISerializationWithImages(t *testing.T) {
	path := writeTinyPNG(t)
	msgs := []Message{
		{Role: RoleUser, Content: "look", Images: []Image{{Path: path}}},
		{Role: RoleTool, ToolCallID: "t1", Content: "done", Images: []Image{{Path: path}}},
	}
	out := oaBuildMessages("sys", msgs)
	// user 消息 → content parts 数组（text + image_url）
	u := out[1]
	if u["role"] != "user" {
		t.Fatalf("role: %v", u["role"])
	}
	parts, _ := json.Marshal(u["content"])
	if !strings.Contains(string(parts), `"image_url"`) || !strings.Contains(string(parts), "data:image/png;base64,") {
		t.Fatalf("user image parts: %s", parts)
	}
	// tool result → tool 消息 + 紧随的 user 附图消息
	if out[2]["role"] != "tool" || out[3]["role"] != "user" {
		t.Fatalf("tool+image layout wrong: %v %v", out[2]["role"], out[3]["role"])
	}
	parts, _ = json.Marshal(out[3]["content"])
	if !strings.Contains(string(parts), "data:image/png") {
		t.Fatalf("tool image parts: %s", parts)
	}
}

func TestAnthropicSerializationWithImages(t *testing.T) {
	path := writeTinyPNG(t)
	msgs := []Message{
		{Role: RoleTool, ToolCallID: "t1", Content: "shot", Images: []Image{{Path: path}}},
		{Role: RoleUser, Content: "look again", Images: []Image{{Path: path}}},
	}
	out := anBuildMessages(msgs, false)
	body, _ := json.Marshal(out)
	if !strings.Contains(string(body), `"type":"tool_result"`) ||
		!strings.Contains(string(body), `"type":"image"`) ||
		!strings.Contains(string(body), `"media_type":"image/png"`) {
		t.Fatalf("anthropic serialization: %s", body)
	}
}

func TestImageUnavailableDegradation(t *testing.T) {
	msgs := []Message{{Role: RoleUser, Content: "look", Images: []Image{{Path: "/nonexistent/shot.png"}}}}
	oa := oaBuildMessages("s", msgs)
	body, _ := json.Marshal(oa[1]["content"])
	if !strings.Contains(string(body), "[image unavailable") {
		t.Fatalf("openai degradation missing: %s", body)
	}
	an := anBuildMessages(msgs, false)
	body, _ = json.Marshal(an[0]["content"])
	if !strings.Contains(string(body), "[image unavailable") {
		t.Fatalf("anthropic degradation missing: %s", body)
	}
}