#include "lua_runner.hpp"
#include <cstring>

extern "C"
{
    #include <errno.h>
    #include "errors.h"
}

Lua_runner::Lua_runner(const char *path)
{
    this->L =NULL;
    this->L = luaL_newstate();
    errno = 0;//清除老错误信息
    if(this->L == NULL){
        errno = NAPI_LUA_STATE_ERROR;
        return ;
    }
    luaL_openlibs(this->L);//创建lua状态机，打开标准库
    const char* save_stdlib_code = 
    "local std = {} "
    "for k, v in pairs(_G) do std[k] = true end "
    "_G.__STD_LIBS = std"; // 将列表存到全局变量 __STD_LIBS 中

    luaL_dostring(this->L, save_stdlib_code);
    /*if(luaL_dostring(this->L,
        "package.path = \";/data/storage/el2/luapkg/?/init.lua\"") != LUA_OK)//TODO  修改加载库的默认路径指向沙盒内路径
        errno = NAPI_LUA_INITFAIL;//加载默认路径*/
    if(path !=NULL)
    {     
        char buf[1024];
        snprintf(buf, sizeof(buf),
            "package.path = package.path .. \";%s\"", 
            path);
        if(luaL_dostring(this->L,buf) != LUA_OK)//加载用户路径
            errno = NAPI_LUA_INITFAIL;
    }
    this->pkg_cont = 0;
}

Lua_runner::~Lua_runner()
{
    lua_close(this->L);
}

bool Lua_runner::check_file_exists(const char *path)
{
    FILE* file = fopen(path, "r");
    if (file) {
        fclose(file);
        return true;
    }
    return false;
}

bool Lua_runner::check_luastatue()
{
        /*检查lua状态机状况*/
    if(this->L == NULL)
    {
        errno = NAPI_LUA_STATE_ERROR;
        return false;
    }
    //分为两部分写，防止空指针访问
    if(lua_status(this->L) !=  LUA_OK)
    {
        errno = NAPI_LUA_STATE_ERROR;
        return false;
    }
    return true;
}

lua_State *Lua_runner::get_lua_State()
{
    return this->L;
}


int Lua_runner::load_lib(const char *path,const char *name)
{
    //如果引入哈希表会导致删除包时的多次哈希查询，污染缓存。同时性能仅与数组实现相当
    if(!this->check_luastatue())
    {
        return -1;
    }
    if(!this->check_file_exists(path))
    {
        errno = NAPI_LOAD_FILE_ERROR;
        return -1;
    }
    if(this->pkg_cont>=MAX_LUA_LIB)
    {
        errno  = NAPI_LUALIB_LOAD_OVER_STACK;
        return -1;
    }
    if(luaL_loadfile(this->L,path)!=LUA_OK)
    {
        const char *ret = lua_tostring(this->L, -1);
        this->reslt = ret;//存储返回值
        errno =NAPI_LOAD_FILE_ERROR;
        lua_pop(this->L,1);
        return -1;
    }
    this->pkgs[this->pkg_cont].ref = lua_gettop(this->L)+1;
    
    snprintf(pkgs[pkg_cont].name,128,"%s",name);
    this->pkg_cont++;
    return 0;
}

int Lua_runner::unload_lib(const char *name)
{
    int sig  = -1;
    for(int i=0;i<this->pkg_cont;i++)
    {
        if(strcmp(this->pkgs[i].name,name) == 0)
        {
            sig = i;
            break;//查找指定的库，查到则将标志位置为库的位置
        }
    }
    if(sig == -1)
    {
        errno = NAPI_UNLOADLIB_FAIL;
        return -1;//没有查到返回异常（尝试卸载未加载的库）
    }
    /*检查lua状态*/
    if(!this->check_luastatue())
    {
        return -1;
    }
    lua_remove(this->L,this->pkgs[sig].ref);
    for(int j = sig+1;j<this->pkg_cont;j++)
    {
        this->pkgs[j-1] = this->pkgs[j];//保持数据结构
        this->pkgs[j-1].ref--;//虚拟栈位置同步变化
    }
    this->pkg_cont--;
    return 1;
}

int Lua_runner::clean()//进行新一轮调用前一定要先clean清除上个脚本执行的痕迹
{
    if(!this->check_luastatue())
    {
        return -1;
    }
    const char* clean_globals_code = 
        "if _G.__STD_LIBS then "
        "  local std = _G.__STD_LIBS "
        "  for k, v in pairs(_G) do "
        "    if not std[k] then _G[k] = nil end "
        "  end "
        "end";
    
    luaL_dostring(this->L, clean_globals_code);//清空全局变量
    luaL_dostring(this->L, "package.loaded = {}");//清空当前引用的包
    for(int i = 0 ;i<this->pkg_cont;i++)
    {
        lua_remove(this->L,this->pkgs[i].ref);
    }
    this->pkg_cont = 0;
    this->reslt ="nil";
    lua_settop(this->L, 0);//清空栈
    return 0;
}

//TODO 支持更多类型的参数 
int Lua_runner::run(const char *path,const char *arg)
{
    if(!this->check_luastatue())//检查lua状态机状态
        return -1;

    if(path != NULL)//加载脚本到栈
    {
        if(this->load_lib(path,path) != 0)
            return -1;
    }
    if(arg != NULL)//压参数入栈
    {
       lua_pushlstring(this->L,arg,strlen(arg));
    }
    if(this->pkg_cont <= 0)//检查是否有可调用chunk
    {
        errno = NAPI_NOCHUNK_FOUND;
        return -1;
    }
    int func_index = this->pkgs[this->pkg_cont-1].ref - 1;
    int top = lua_gettop(this->L);
    int argcount = top - func_index;//获取入参数量
    if(argcount<0)
    {
        errno = NAPI_LUA_STACK_ERROR;
        return -1;
    }//检查参数数量
    if(lua_pcall(this->L,argcount,LUA_MULTRET,0)== LUA_OK)
    {
        if(lua_isstring(this->L,-1))
            this->reslt = lua_tostring(this->L,-1);
        this->pkg_cont--;
        return 0;
    }
    else
    {
        errno = NAPI_SCRIPT_ERROR;
        this->reslt = lua_tostring(this->L,-1);
        this->pkg_cont--;
        lua_pop(L,1);//错误出栈
        return -1;
    }
}
//TODO 实现函数调用 achieve func call via file
/*
int Lua_runner::callfunction()
{
    return 0;
}
 */