package main

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

// EsDLL Elasticsearch工具DLL结构
type esDLL struct {
	dll              *syscall.DLL
	listAllIndices   *syscall.Proc // 查询所有索引
	getIndicesInfo   *syscall.Proc // 获取所有索引的详细信息
	getIndexDetail   *syscall.Proc // 获取单个索引的详细信息
	createIndex      *syscall.Proc // 创建索引
	deleteIndex      *syscall.Proc // 删除索引
	getDocumentCount *syscall.Proc // 获取索引文档数量
	createDocument   *syscall.Proc // 创建文档
	getDocument      *syscall.Proc // 根据ID获取文档
	updateDocument   *syscall.Proc // 更新文档
	deleteDocument   *syscall.Proc // 删除文档
	searchDocuments  *syscall.Proc // 搜索文档
	freeCString      *syscall.Proc // 释放C字符串
}

// 初始化esDLL
func InitEsDLL() (*esDLL, error) {
	dllPath := filepath.Join("es", "dll", "es.dll")
	if _, err := os.Stat(dllPath); os.IsNotExist(err) {
		return nil, fmt.Errorf("es DLL 不存在: %s", dllPath)
	}
	if dll, err := syscall.LoadDLL(dllPath); err != nil {
		return nil, fmt.Errorf("加载es DLL 失败: %s", err)
	} else {
		return &esDLL{
			dll:              dll,
			listAllIndices:   dll.MustFindProc("ListAllIndices"),
			getIndicesInfo:   dll.MustFindProc("GetIndicesInfo"),
			getIndexDetail:   dll.MustFindProc("GetIndexDetail"),
			createIndex:      dll.MustFindProc("CreateIndex"),
			deleteIndex:      dll.MustFindProc("DeleteIndex"),
			getDocumentCount: dll.MustFindProc("GetDocumentCount"),
			createDocument:   dll.MustFindProc("CreateDocument"),
			getDocument:      dll.MustFindProc("GetDocument"),
			updateDocument:   dll.MustFindProc("UpdateDocument"),
			deleteDocument:   dll.MustFindProc("DeleteDocument"),
			searchDocuments:  dll.MustFindProc("SearchDocuments"),
			freeCString:      dll.MustFindProc("FreeCString"),
		}, nil
	}
}

// cStr 获取C字符串
func (m *esDLL) cStr(p uintptr) string {
	if p == 0 {
		return ""
	}
	b := []byte{}
	for i := uintptr(0); ; i++ {
		c := *(*byte)(unsafe.Pointer(p + i))
		if c == 0 {
			break
		}
		b = append(b, c)
	}
	s := string(b)
	if m.freeCString != nil {
		m.freeCString.Call(p)
	}
	return s
}

// 查询所有索引
func (m *esDLL) ListAllIndices() (string, error) {
	proc, err := m.dll.FindProc("ListAllIndices")
	if err != nil {
		return "", fmt.Errorf("找不到函数 ListAllIndices: %v", err)
	}
	resultPtr, _, _ := proc.Call()
	result := m.cStr(resultPtr)
	return result, nil
}

func (m *esDLL) CreateDocument(indexName string, id string, doc interface{}) (string, error) {
	proc, err := m.dll.FindProc("CreateDocument")
	if err != nil {
		return "", fmt.Errorf("找不到函数 CreateDocument: %v", err)
	}
	docJson, err := json.Marshal(doc)
	if err != nil {
		return "", err
	}
	indexNamePtr, _ := syscall.BytePtrFromString(indexName)
	idPtr, _ := syscall.BytePtrFromString(id)
	docJsonPtr, _ := syscall.BytePtrFromString(string(docJson))

	resultPtr, _, _ := proc.Call(
		uintptr(unsafe.Pointer(indexNamePtr)),
		uintptr(unsafe.Pointer(idPtr)),
		uintptr(unsafe.Pointer(docJsonPtr)),
	)
	result := m.cStr(resultPtr)
	return result, nil
}

//func main() {
//	dll, err := InitEsDLL()
//	if err != nil {
//		fmt.Println(err)
//	}
//	//indices, err := dll.ListAllIndices()
//	//if err != nil {
//	//	fmt.Println(err)
//	//}
//	//fmt.Println(string(indices))
//
//	doc := Document{
//		ID:        "10003",
//		Title:     "测试文档3",
//		Content:   "这是一个测试文档3",
//		Author:    "测试员3",
//		CreatedAt: time.Now(),
//		Tags:      []string{"测试3", "文档3"},
//	}
//	document, err := dll.CreateDocument("test-cc", doc.ID, doc)
//	if err != nil {
//		fmt.Println(err)
//	}
//	fmt.Println(document)
//}