package upload

import (
	"context"
	"encoding/base64"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"qnc-server/app/main/api/internal/svc"
	"qnc-server/app/main/api/internal/types"
	"qnc-server/common/xerr"

	"github.com/google/uuid"
	"github.com/pkg/errors"
	"github.com/zeromicro/go-zero/core/logx"
)

const uploadImageDir = "uploads/images"

type UploadImageLogic struct {
	logx.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

func NewUploadImageLogic(ctx context.Context, svcCtx *svc.ServiceContext) *UploadImageLogic {
	return &UploadImageLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

func (l *UploadImageLogic) UploadImage(req *types.UploadImageReq) (*types.UploadImageResp, error) {
	raw := strings.TrimSpace(req.ImageBase64)
	if raw == "" {
		return nil, errors.Wrapf(xerr.NewErrMsg("image_base64 不能为空"), "")
	}
	if idx := strings.Index(raw, ","); idx >= 0 {
		raw = raw[idx+1:]
	}
	data, err := base64.StdEncoding.DecodeString(raw)
	if err != nil {
		return nil, errors.Wrapf(xerr.NewErrMsg("图片 Base64 解析失败"), "")
	}
	if len(data) == 0 {
		return nil, errors.Wrapf(xerr.NewErrMsg("图片内容为空"), "")
	}
	if len(data) > 5*1024*1024 {
		return nil, errors.Wrapf(xerr.NewErrMsg("图片不能超过 5MB"), "")
	}

	ext := detectImageExt(data)
	fileName := fmt.Sprintf("%s%s", uuid.NewString(), ext)
	dir := uploadImageDir
	if err := os.MkdirAll(dir, 0o755); err != nil {
		return nil, errors.Wrapf(xerr.NewErrCode(xerr.SERVER_COMMON_ERROR), "创建上传目录失败: %v", err)
	}
	fullPath := filepath.Join(dir, fileName)
	if err := os.WriteFile(fullPath, data, 0o644); err != nil {
		return nil, errors.Wrapf(xerr.NewErrCode(xerr.SERVER_COMMON_ERROR), "保存图片失败: %v", err)
	}

	base := publicAPIBase(l.svcCtx.Config.Promotion.OfficialDomain)
	url := fmt.Sprintf("%s/api/v1/upload/file/%s", base, fileName)
	return &types.UploadImageResp{Url: url}, nil
}

func detectImageExt(data []byte) string {
	if len(data) >= 3 && data[0] == 0xFF && data[1] == 0xD8 && data[2] == 0xFF {
		return ".jpg"
	}
	if len(data) >= 8 && string(data[0:8]) == "\x89PNG\r\n\x1a\n" {
		return ".png"
	}
	if len(data) >= 6 && string(data[0:6]) == "GIF87a" || string(data[0:6]) == "GIF89a" {
		return ".gif"
	}
	if len(data) >= 12 && string(data[8:12]) == "WEBP" {
		return ".webp"
	}
	return ".jpg"
}

func publicAPIBase(officialDomain string) string {
	base := strings.TrimRight(officialDomain, "/")
	if base != "" {
		return base
	}
	return "http://127.0.0.1:8888"
}