package services

import (
	"encoding/base64"
	"fmt"
	"strings"

	"sproutclaw-web/internal/models"
)

const (
	maxImages    = 8
	maxImageSize = 10 * 1024 * 1024 // 10 MB
)

var allowedImageTypes = map[string]bool{
	"image/jpeg": true,
	"image/png":  true,
	"image/gif":  true,
	"image/webp": true,
}

// ValidateImages checks image count, type, and base64-decoded size.
func ValidateImages(images []models.ChatImage) error {
	if len(images) > maxImages {
		return fmt.Errorf("最多支持 %d 张图片，当前 %d 张", maxImages, len(images))
	}
	for i, img := range images {
		mt := strings.ToLower(img.MediaType)
		if !allowedImageTypes[mt] {
			return fmt.Errorf("图片 %d 类型不支持: %s", i+1, img.MediaType)
		}
		decoded, err := base64.StdEncoding.DecodeString(img.Data)
		if err != nil {
			return fmt.Errorf("图片 %d base64 解码失败", i+1)
		}
		if len(decoded) > maxImageSize {
			return fmt.Errorf("图片 %d 超过 10MB 限制", i+1)
		}
	}
	return nil
}