//  Copyright (c) 2005-2008 Hartmut Kaiser
// 
//  Distributed under the Boost Software License, Version 1.0. (See accompanying 
//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef ADAPTORS_DEFAULT_FILE_COMMON_HELPERS_HPP
#define ADAPTORS_DEFAULT_FILE_COMMON_HELPERS_HPP

#include <climits>
#include <boost/filesystem/path.hpp>
#include <boost/algorithm/string/predicate.hpp>


#ifndef  MAX_PATH
# define MAX_PATH _POSIX_PATH_MAX
#endif

///////////////////////////////////////////////////////////////////////////////
namespace detail
{
    ///////////////////////////////////////////////////////////////////////////
    inline std::ios_base::openmode 
    translate_open_mode (saga::filesystem::flags saga_mode)
    {
      int mode = std::ios::binary;

      if ( saga_mode & saga::filesystem::Read ) 
      {
        mode |= std::ios::in;

        if ( saga_mode & saga::filesystem::Append )
        {
          mode |= std::ios::ate;
        }
      }

      if ( saga_mode & saga::filesystem::Write ) 
      {
        mode |= std::ios::out;

        if ( saga_mode & saga::filesystem::Append )
        {
          mode |= std::ios::ate;
        }
      }

      if ( saga_mode & saga::filesystem::Binary ) 
      {
        mode |= std::ios::binary;
      }

      if (saga_mode & saga::filesystem::Truncate) 
      {
        mode |= std::ios::trunc;
      }

      return (std::ios_base::openmode) mode;
    }

    ///////////////////////////////////////////////////////////////////////////
    // wrapper for gethostname()
    inline std::string get_hostname()
    {
        char buffer[MAX_PATH] = { '\0' };
        gethostname(buffer, sizeof(buffer));
        return std::string(buffer);
    }

    ///////////////////////////////////////////////////////////////////////////
    inline std::string 
    get_filepath(saga::url const& loc)
    {
        return loc.get_path();
    }

    ///////////////////////////////////////////////////////////////////////////
    inline std::string 
    get_scheme_authority(saga::url const& file_url)
    {
        std::string result (file_url.get_scheme());
        if (!result.empty())
        {
            result += ':';
        }
    
        std::string authority (file_url.get_authority());
        if (!authority.empty())
        {
            result += "//";
            result += authority;
            result += '/';
        }
        return result;
    }

#if defined(SAGA_DEFAULT_FILE_ADAPTOR_USE_CURL)
    ///////////////////////////////////////////////////////////////////////////
    inline saga::url
    complete_path(std::string root, std::string path)
    {
        namespace fs = boost::filesystem;
    
        saga::url root_url(root);
        saga::url path_url(path);
        if (root_url.get_scheme() != path_url.get_scheme() ||
            root_url.get_authority() != path_url.get_authority())
        {
            return path_url;    // different hosts or schemes, use path as is
        }
        
        // same host and scheme, might be a relative path
        fs::path fs_path (get_filepath(path), fs::native);
        if (!fs_path.has_root_path()) {
            // path refers to a relative directory, generate an absolute name
            // using the given root
            fs::path fs_root (root_url.get_path(), fs::native);
            fs_root /= fs_path;
            root_url.set_scheme_specific_part(fs_root.get_path());
            return root_url;
        }
        return path_url;  // path refers to an absolute path, use as is
    }
#endif
    
    ///////////////////////////////////////////////////////////////////////////
    inline bool
    file_islocal(saga::url const& file_url)
    {
    // we consider a file to be local if it's located on the local host
        std::string host(file_url.get_host());
        if (!host.empty() && host != "localhost" && !boost::iequals(host, get_hostname()))
            return false;   // remote files are not local

    // we consider a file to be local if it has no scheme at all or if the scheme 
    // if file or any, given that the host is the local host
        std::string scheme(file_url.get_scheme());
        return scheme.empty() || scheme == "file" || scheme == "any";
    }

    ///////////////////////////////////////////////////////////////////////////
    inline bool
    file_ftp(saga::url const& file_url)
    {
        std::string scheme(file_url.get_scheme());
        return scheme == "ftp" || scheme == "ftps";
    }

    ///////////////////////////////////////////////////////////////////////////
    inline bool
    file_http(saga::url const& file_url)
    {
        std::string scheme(file_url.get_scheme());
        return scheme == "http" || scheme == "https";
    }

    // convert a SAGA pattern into a TR1::regex 
    inline std::string 
    regex_from_character_set(std::string::const_iterator& it, 
        std::string::const_iterator end)
    {
        std::string::const_iterator start = it;
        std::string result(1, *it);  // copy '['
        if (*++it == '!') {
            result.append(1, '^');   // negated character set
        }
        else if (*it == ']') {
            SAGA_ADAPTOR_THROW_NO_CONTEXT(
                "Invalid pattern (empty character set) at: " + 
                std::string(start, end), saga::NoSuccess);
        }
        else {
            result.append(1, *it);   // append this character
        }
        
        // copy while in character set
        while (++it != end) {
            result.append(1, *it);
            if (*it == ']')
                break;
        }
        
        if (it == end || *it != ']') {
            SAGA_ADAPTOR_THROW_NO_CONTEXT(
                "Invalid pattern (missing closing ']') at: " + 
                std::string(start, end), saga::NoSuccess);
        }

        return result;
    }
    
    inline std::string 
    regex_from_string_choice(std::string::const_iterator& it, 
        std::string::const_iterator end)
    {
        std::string::const_iterator start = it;
        std::string result(1, '(');

        // copy while in string choice
        bool has_one = false;
        while (++it != end && *it != '}') {
            if (*it == ',') {
                if (!has_one) {
                    SAGA_ADAPTOR_THROW_NO_CONTEXT(
                        "Invalid pattern (empty string alternative) at: " + 
                        std::string(start, end), saga::NoSuccess);
                }
                result.append(1, '|');
                has_one = false;
            }
            else {
                result.append(1, *it);
                has_one = true;
            }
        }
        
        if (it == end || *it != '}') {
            SAGA_ADAPTOR_THROW_NO_CONTEXT(
                "Invalid pattern (missing closing '}') at: " + 
                std::string(start, end), saga::NoSuccess);
        }
        
        result.append(1, ')');
        return result;
    }
    
    inline std::string 
    regex_from_pattern(std::string const& pattern)
    {
        std::string result;
        std::string::const_iterator end = pattern.end();
        for (std::string::const_iterator it = pattern.begin(); it != end; ++it)
        {
            char c = *it;
            switch (c) {
            case '*':
                result.append(".*");
                break;
                
            case '?':
                result.append(1, '.');
                break;
                
            case '[':
                result.append(regex_from_character_set(it, end));
                break;
                
            case '{':
                result.append(regex_from_string_choice(it, end));
                break;
                
            case '\\':
                if (++it == end) {
                    SAGA_ADAPTOR_THROW_NO_CONTEXT(
                        "Invalid escape sequence at: " + pattern,
                        saga::NoSuccess);
                }
                result.append(1, *it);
                break;
                
            default:
                result.append(1, c);
                break;
            }
        }
        return result;
    }
    
///////////////////////////////////////////////////////////////////////////////
}   // namespace detail

#endif // !ADAPTORS_DEFAULT_FILE_COMMON_HELPERS_HPP