#include <stdlib.h>
#include <sys/stat.h>
#include <syslog.h>
#include <iostream>
#include <cassert>
#include <stdexcept>
#include <algorithm>
#include <numeric>
#include <openssl/md5.h>
#include "eyetil.h"

#include "config.h"
#ifdef HAVE_LIBUUID
# include <uuid/uuid.h>
#endif

binary_t& binary_t::from_hex(const std::string& h) {
    std::string::size_type hs = h.length();
    if(hs&1)
	throw std::runtime_error("odd number of characters in hexadecimal number");
    int rvs = hs>>1;
    resize(rvs);
    const unsigned char *hp = (const unsigned char*)h.data();
    iterator oi=begin();
    char t[3] = { 0,0,0 };
    for(int i=0;i<rvs;++i) {
	t[0]=*(hp++); t[1]=*(hp++);
	*(oi++) = strtol(t,0,16);
    }
    return *this;
}

binary_t& binary_t::from_data(const void *d,size_t s) {
    resize(s);
    std::copy((const unsigned char*)d,(const unsigned char *)d+s,
	    begin() );
    return *this;
}

binary_t& binary_t::make_nonce() {
#ifdef HAVE_LIBUUID
    uuid_t uuid;
    uuid_generate(uuid);
    from_data((unsigned char*)uuid,sizeof(uuid));
#else
    resize(16);
    std::generate_n(begin(),16,rand);
#endif /* HAVE_LIBUUID */
    return *this;
}

std::string binary_t::hex() const {
    std::string rv;
    rv.reserve((size()<<1)+1);
    char t[3] = {0,0,0};
    for(const_iterator i=begin(),ie=end();i!=ie;++i) {
	int rc = snprintf(t,sizeof(t),"%02x",*i);
	assert(rc<sizeof(t));
	rv += t;
    }
    return rv;
}

binary_t binary_t::md5() const {
    binary_t rv(MD5_DIGEST_LENGTH);
    if(!MD5(
		(const unsigned char*)&(front()),size(),
		(unsigned char*)&(rv.front()) ))
	throw std::runtime_error("failed to md5()");
    return rv;
}

static void make_path_for_template(const std::string& p,mode_t m) {
    struct stat st;
    std::string pp;
    for(std::string::size_type sl=p.find('/',1);
	    sl!=std::string::npos;
	    sl=p.find('/',sl+1)) {
	if(stat( (pp=p.substr(0,sl)).c_str() ,&st)
		|| !S_ISDIR(st.st_mode)) {
	    if(mkdir(pp.c_str(),m))
		throw std::runtime_error("failed to mkdir()");
	}
    }
}

tmpdir_t::tmpdir_t(const std::string& dt) : dir(dt) {
    make_path_for_template(dt,0777);
    if(!mkdtemp((char*)dir.data()))
	throw std::runtime_error("failed to mkdtmp()");
}
tmpdir_t::~tmpdir_t() {
    assert(!dir.empty());
    if(rmdir(dir.c_str())) {
	syslog(LOG_WARNING,"Failed to remove '%s' directory",dir.c_str());
    }
}

std::string tmpdir_t::get_file(const std::string& f) {
    std::string::size_type ls = f.rfind('/');
    return dir+'/'+(
	    (ls==std::string::npos)
	    ? f
	    : f.substr(ls+1)
	);
}

tarchive_t::tarchive_t(void *p,size_t s) : a(archive_read_new()), e(0) {
    if(!a) throw std::runtime_error("failed to archive_read_new()");
    if(archive_read_support_format_tar(a)) {
	archive_read_finish(a);
	throw std::runtime_error("failed to archive_read_support_format_tar()");
    }
    if(archive_read_open_memory(a,p,s)) {
	archive_read_finish(a);
	throw std::runtime_error("failed to archive_read_open_memory()");
    }
}
tarchive_t::~tarchive_t() {
    assert(a);
    archive_read_finish(a);
}

bool tarchive_t::read_next_header() {
    assert(a);
    return archive_read_next_header(a,&e)==ARCHIVE_OK;
}

std::string tarchive_t::entry_pathname() {
    assert(a); assert(e);
    return archive_entry_pathname(e);
}

bool tarchive_t::read_data_into_fd(int fd) {
    assert(a);
    return archive_read_data_into_fd(a,fd)==ARCHIVE_OK;
}

#pragma pack(1)
struct block512_t {
    enum { words = 512 / sizeof(uint16_t) };
    uint16_t data[words];

    static uint16_t tcpcksum(block512_t& data) {
	uint32_t sum = std::accumulate(data.data,data.data+words,0);
	while(uint32_t hw = sum>>16) sum = (sum&0xffff)+hw;
	return ~sum;
    }

};
#pragma pack()

binary_t integrity_digest(const void *ptr,size_t size,const std::string& ukey) {
    binary_t key; key.from_hex(ukey);
    std::vector<uint16_t> blksums; blksums.reserve(size/sizeof(block512_t));
    block512_t *db = (block512_t*)ptr,
	       *de = db + size/sizeof(block512_t);
    std::transform( db, de, std::back_inserter(blksums), block512_t::tcpcksum );
    binary_t subject;
    subject.from_data((void*)&(blksums.front()),blksums.size()*sizeof(uint16_t));
    std::copy( key.begin(), key.end(), std::back_inserter(subject) );
    return subject.md5();
}