package main

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"syscall"
	"unsafe"
)

// ImageDLL 图片处理DLL结构
type imageDLL struct {
	dll                            *syscall.DLL
	processImage                   *syscall.Proc
	createWhiteBottomCenteredImage *syscall.Proc
	freeCString                    *syscall.Proc
}

// 初始化imageDLL
func InitImageDll() (*imageDLL, error) {
	dllPath := filepath.Join("image", "dll", "image.dll")
	if _, err := os.Stat(dllPath); os.IsNotExist(err) {
		return nil, fmt.Errorf("image DLL 不存在: %s", dllPath)
	}
	if dll, err := syscall.LoadDLL(dllPath); err != nil {
		return nil, fmt.Errorf("加载image DLL 失败: %s", err)
	} else {
		return &imageDLL{
			dll:                            dll,
			processImage:                   dll.MustFindProc("ProcessImage"),
			createWhiteBottomCenteredImage: dll.MustFindProc("CreateWhiteBottomCenteredImage"),
			freeCString:                    dll.MustFindProc("FreeCString"),
		}, nil
	}
}

func (m *imageDLL) ProcessImage(config *Config) error {
	marshal, err := json.Marshal(config)
	if err != nil {
		return fmt.Errorf("json转换失败: %s", err)
	}
	fromString, _ := syscall.BytePtrFromString(string(marshal))
	info, _, _ := m.processImage.Call(uintptr(unsafe.Pointer(fromString)))
	cStr(info)
	return nil
}

func (m *imageDLL) CreateWhiteBottomCenteredImage(config *Config, w int, h int) (string, error) {
	proc, err2 := m.dll.FindProc("CreateWhiteBottomCenteredImage")
	if err2 != nil {
		return "", err2
	}
	marshal, err := json.Marshal(config)
	if err != nil {
		return "", fmt.Errorf("json转换失败: %s", err)
	}

	fromString, _ := syscall.BytePtrFromString(string(marshal))
	info, _, _ := proc.Call(uintptr(unsafe.Pointer(fromString)), uintptr(w), uintptr(h))
	return cStr(info), nil
}

// cStr 将 C 字符串指针转换为 Go 字符串
func cStr(ptr uintptr) string {
	if ptr == 0 {
		return ""
	}
	var b []byte
	for {
		c := *(*byte)(unsafe.Pointer(ptr))
		if c == 0 {
			break
		}
		b = append(b, c)
		ptr++
	}
	return string(b)
}

func main() {

	config := &Config{
		OutputDir:      "D:\\isbn_images\\result", // 输出根目录
		FileName:       "D:\\isbn_images\\result\\9771671688095.jpg",
		MatchDir:       "matched",   // 满足条件的图片目录
		UnmatchDir:     "unmatched", // 不满足条件的图片目录
		WhiteDir:       "white",
		EqualHeightDir: "equalHeight",
		MinWhitePct:    0.1,  // 纯白占比下限 10%
		MaxWhitePct:    0.65, // 纯白占比上限 90%
		Extensions:     []string{"jpg", "jpeg", "png", "gif", "bmp", "webp"},
	}

	dll, err := InitImageDll()
	if err != nil {
		fmt.Println(err)
	}
	//err = dll.ProcessImage(config)
	//if err != nil {
	//	fmt.Println(err)
	//}

	image, err := dll.CreateWhiteBottomCenteredImage(config, 800, 800)
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println(image)
}