#include "filesystem.hpp"

#include <sys/sendfile.h>
#include <fcntl.h>
#include <fts.h>
#include <dirent.h>
#include <sys/stat.h>
#include <zconf.h>
#include <unistd.h>

void Filesystem::CreateDirectory(const std::string& path)
{
    mkdir(path.c_str(), 0755);
}

void Filesystem::CopyFile(const std::string& src, const std::string& dst, bool overwrite)
{
    int read_fd;
    int write_fd;
    struct stat stat_buf;
    off_t offset = 0;

    read_fd = open(src.c_str(), O_RDONLY);
    fstat (read_fd, &stat_buf);

    int wflags =  O_WRONLY | O_CREAT;
    if(overwrite)
        wflags |= O_TRUNC;

    write_fd = open(dst.c_str(), wflags, stat_buf.st_mode);

    sendfile(write_fd, read_fd, &offset, stat_buf.st_size);

    close(read_fd);
    close(write_fd);
}

void Filesystem::CopyDirectory(const std::string& src, const std::string& dst, bool overwrite)
{
    CreateDirectory(dst);

    char* paths[] = { const_cast<char*>(src.c_str()), 0 };
    FTS* tree = fts_open(paths, FTS_NOCHDIR, 0);

    FTSENT *node;
    while ((node = fts_read(tree)))
    {
        if(node->fts_level > 0 && node->fts_name[0] == '.')
        {
            fts_set(tree, node, FTS_SKIP);
        }
        else if(node->fts_info & FTS_F)
        {
            CopyFile(node->fts_path, dst + Utility::RemoveSubstrings(node->fts_path, { src }), overwrite);
        }
        else if(node->fts_info & FTS_D)
        {
            CreateDirectory(dst + Utility::RemoveSubstrings(node->fts_path, { src }));
        }
    }

    fts_close(tree);
}

void Filesystem::Remove(const std::string& path)
{
    unlink(path.c_str());
}

std::string Filesystem::Canonical(const std::string& path)
{
    char* n = new char[PATH_MAX];
    realpath(path.c_str(), n);

    return n;
}

std::vector<std::string> Filesystem::DirectoryContents(const std::string& directory)
{
    std::vector<std::string> tmp;

    char* paths[] = { const_cast<char*>(directory.c_str()), 0 };
    FTS* tree = fts_open(paths, FTS_NOCHDIR, 0);

    FTSENT *node;
    while ((node = fts_read(tree)))
    {
        if(node->fts_level > 0 && node->fts_name[0] == '.')
        {
            fts_set(tree, node, FTS_SKIP);
        }
        else if(node->fts_info & FTS_F)
        {
            tmp.push_back(std::string(node->fts_accpath));
        }
    }

    fts_close(tree);

    return tmp;
}

bool Filesystem::DirectoryExists(const std::string& path)
{
    DIR* dir = opendir(path.c_str());

    return dir != nullptr;
}

bool Filesystem::FileExists(const std::string& path)
{
    return access(path.c_str(), F_OK) != -1;
}