package service

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"strings"
	"time"
)

// AIBBox 检测框
type AIBBox struct {
	X float64 `json:"x"`
	Y float64 `json:"y"`
	W float64 `json:"w"`
	H float64 `json:"h"`
}

// AIDetection 单条检测结果
type AIDetection struct {
	BBox       AIBBox  `json:"bbox"`
	ClassName  string  `json:"class"`
	Confidence float64 `json:"confidence"`
}

// AIDetectResponse /detect 响应
type AIDetectResponse struct {
	Model               string        `json:"model"`
	ModelVersion        string        `json:"modelVersion"`
	IsMock              bool          `json:"isMock"`
	Status              string        `json:"status"`
	AbnormalProbability float64       `json:"abnormalProbability"`
	Detections          []AIDetection `json:"detections"`
}

// AIDetectionStatus 从检测结果归纳 AI 状态；空检测或 unknown 不当作 healthy。
func AIDetectionStatus(detections []AIDetection) string {
	if len(detections) == 0 {
		return "unknown"
	}
	healthySeen := false
	unknownSeen := false
	for _, d := range detections {
		class := strings.ToLower(strings.TrimSpace(d.ClassName))
		switch class {
		case "healthy":
			healthySeen = true
		case "", "unknown":
			unknownSeen = true
		default:
			return "abnormal"
		}
	}
	if healthySeen && !unknownSeen {
		return "healthy"
	}
	return "unknown"
}

// AIClient ai-service HTTP 客户端
type AIClient struct {
	baseURL string
	client  *http.Client
}

// NewAIClient 创建 AI 客户端
func NewAIClient(baseURL string) *AIClient {
	return &AIClient{
		baseURL: strings.TrimSuffix(baseURL, "/"),
		client:  &http.Client{Timeout: 30 * time.Second},
	}
}

// Detect 上传图片到 ai-service /detect，返回检测结果（无状态接口，天然幂等）
func (c *AIClient) Detect(ctx context.Context, imageBytes []byte, filename string) (*AIDetectResponse, error) {
	start := time.Now()
	var body bytes.Buffer
	writer := multipart.NewWriter(&body)
	part, err := writer.CreateFormFile("file", filename)
	if err != nil {
		return nil, err
	}
	if _, err := part.Write(imageBytes); err != nil {
		return nil, err
	}
	if err := writer.Close(); err != nil {
		return nil, err
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+"/detect", &body)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", writer.FormDataContentType())

	resp, err := c.client.Do(req)
	latency := time.Since(start)
	if err != nil {
		RecordDependency(DependencyAI, err, latency)
		return nil, err
	}
	defer resp.Body.Close()

	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		err := fmt.Errorf("ai-service /detect 返回 %d: %s", resp.StatusCode, string(data))
		RecordDependency(DependencyAI, err, latency)
		return nil, err
	}

	var out AIDetectResponse
	if err := json.Unmarshal(data, &out); err != nil {
		RecordDependency(DependencyAI, err, latency)
		return nil, err
	}
	RecordDependency(DependencyAI, nil, latency)
	return &out, nil
}