#include "config.h"
#include "global.h"
#include "helpers.h"
#include "FileEntity.h" // using Entity.cpp
#include "Loggers.h"
#include "Birthcert.h"
#include "sha1.hpp"

FileEntityPtr makeFileEntity(fs::path path)
{
 auto it = map_file_path_to_ptr.find(path.string());
 if (it != map_file_path_to_ptr.end()) {
 return it->second;
 }
 
 FileEntityPtr p{ new FileEntity(path) };
 map_file_path_to_ptr[path.string()] = p;

 return p;
}

FileEntity::FileEntity(fs::path path)
:
 m_path(path)
{
}

string FileEntity::name()
{
 return m_path.string();
}


fs::path FileEntity::path()
{
 return m_path;
}

bool FileEntity::update()
{
 MINILOG(update_logger, "Entity::update: " << name());
 // 如果一个文件节点是个叶子节点
 if (prerequisiteList.empty()) {
 return exists(m_path); // 存在就好,不存在那就真没办法了
 }

 // 不是叶子节点的话,先把所有的下级节点更新一下
 DepInfo info;
 info.target = shared_from_this();
 info.all = prerequisiteList;

 updatePrerequisites(info);

 // 然后再判断是否要执行本节点关联的动作
 if (needExecuteActions(info)) {
 MINILOG(update_logger, "Entity::needExecuteActions: true " << name());
 return executeActions(info);
 }


 return true;
}

// 若文件不存在,就认为它的生日为0
// 若它作为目标文件,生日为0意味着这是一个最古老的文件,它比任何依赖文件都要老,所以必须重新生成
// 若它作为依赖文件,生日0意味着文件不存在,没法用它生成目标文件
// todo:如果一个文件不存在,让这个函数抛出异常。
// time_t FileEntity::timestamp()
// {
// time_t timestamp;
// if (!exists(m_path))
// timestamp = 0;
// else {
// // timestamp is the modification time of file
// timestamp = last_write_time(m_path);
// }
// return timestamp;
// }

FileSig FileEntity::sig()
{
 FileSig sig;
 sig.path = m_path;
 //cout << "cccccccccccccc\n";
 // sig.timestamp = last_write_time(m_path);
 // sig.size = file_size(m_path);
 sig.sha1 = SHA1::from_file(m_path.string());
 return sig;
}

// 判断是否需要执行关联的动作
bool FileEntity::needExecuteActions(const DepInfo& info)
{
 //cout << "execing needExecuteActions" << this->path() << endl;
 // 如果本身还不存在,要重新生成
 if (!exists(path()))
 return true;

 // 如果有下级节点更新没成功,也去更新本节点,因为动作未必在乎
 if (!info.failed.empty())
 return true;

 // // 如果下级节点有变,它要重新生成
 // if (!info.changed.empty())
 // return true;


 // 如果没有下级节点,就不需要更新本节点
 if (prerequisiteList.empty())
 return false;

 // 有下级节点的,还要看一下下级结点跟自己出身证明上记录的是否一致
 // birthcert中记录的下级文件,可能少于.d中列出的下级文件。(这种情况发生在第一与第二次执行之间)
 fs::path birthcert_path = shadow(path());
 birthcert_path += ".birthcert";

 ifstream ifs(birthcert_path.string());
 //cout << "birthcert: " << birthcert_path.string() << endl;
 //assert(ifs);
 // .obj跟出生证明生死与共,但从.fl产生的.cxx文件在,其出生证明未必在。因为.cxx虽是自动生成,但不在cache中。
 if (!ifs)
 return true;

 boost::archive::text_iarchive ia(ifs);

 Birthcert birthcert;
 ia >> birthcert;

 for (auto p : prerequisiteList) {
 FileEntityPtr fp = static_pointer_cast<FileEntity>(p);

 if (birthcert.verifySig(fp->path().string(), fp->sig()) == false)
 return true;
 }

 return false;
}


void get_pre_file_paths_from_dep_file(fs::path dep_path, vector<fs::path>& pre_file_paths)
{
 ifstream f(dep_path.string());
 assert(f);
	if (!f)
		return;

 istream_iterator<string> i = istream_iterator<string>(f);

 // skip the first
 int count = 0;
 while (count < 1) {
 if (*i != "\\")
 count++;
 ++i;
 }

 for (; i != istream_iterator<string>(); ++i) {
 string t = *i;
 if (t != "\\") {
 fs::path p(t);
 pre_file_paths.push_back(p);
 }
 }
}


 // (根据.d文件中指出的依赖关系)生成出生证明文件
 void FileEntity::generate_birth_cert(fs::path dep_path)
 {
 vector<fs::path> pre_file_paths;
 get_pre_file_paths_from_dep_file(dep_path, pre_file_paths);

 generate_birth_cert(pre_file_paths);
 }

void FileEntity::generate_birth_cert()
{
 vector<fs::path> pre_file_paths;
 for (auto p : prerequisiteList) {
 if (p->isFile()) {
 FileEntityPtr f = static_pointer_cast<FileEntity>(p);
 pre_file_paths.push_back(f->path());
 }
 }


 generate_birth_cert(pre_file_paths);
}

void FileEntity::generate_birth_cert(const vector<fs::path>& pre_file_paths)
{
 Birthcert birthcert;
 for (auto p : pre_file_paths) {
 FileEntityPtr f = makeFileEntity(p);
 birthcert.addSig(f->path().string(), f->sig());
 }

 //cout << "before shadow: " << this->path() << endl;
 fs::path birthcert_path = shadow(this->path());
 //cout << "after shadow: " << birthcert_path << endl;
 birthcert_path += ".birthcert";
 ofstream ofs(birthcert_path.string());
 assert(ofs);
 boost::archive::text_oarchive oa(ofs);

 oa << birthcert;
}