// MailHeaders.hpp
// Copyright (C) 2008 ARM Research Labs, LLC.
// See www.armresearch.com for the copyright terms.
//
// Header file for MailHeaders.cpp.

#ifndef MailHeadershpp_included
#define MailHeadershpp_included

#include <string>

using namespace std;

/// Class to extract mail header name/body pairs.
//
// This class extracts mail header name/body pairs from a string
// containing a series of mail headers.
//
class MailHeaders {
private:
    string Buffer;                                                              ///< Contains the mail headers.
    const string SMTPENDL;                                                      ///< STMP end-of-line string (e.g. "\r\n).
    const string LibMilterENDL;                                                 ///< libmilter end-of-line string.
    const string Prefix;                                                        ///< Start of header name (e.g. "X-").

    /// Get the next header name and body.
    //
    // This method inputs a string containing zero or more RFC
    // 2822-compliant headers, and returns the header name and body in
    // a format suitable for adding the header using the libmilter
    // library.  The header name, ":", body, and the trailing SMTPENDL
    // are removed from the input string.
    //
    // \param[out] HeaderName contains the name of the header.
    //
    // \param[in,out] Buffer on input contains the headers.  On output,
    // the name of the first header, the ":", header body, and trailing
    // SMTPENDL are removed from the beginning.
    //
    // \returns true if a header is found, false if Buffer is "".
    //
    // \throws std::invalid_argument if Buffer does not have the correct
    // format.
    //
    // \see getHeaderLine.
    //
    // \see getHeaderBody.
    //
    bool getHeaderName(std::string *HeaderName);

    /// Get the next line of a mail header.
    //
    // This method inputs a string containing zero or more lines of
    // the body of a RFC 2822-compliant header, and returns the next
    // line of the body of the header.  The line and the SMTPENDL are
    // removed from the input string Buffer.
    //
    // \param[out] HeaderLine contains the line of the header.
    //
    // \returns true if a line is found, false if Buffer is "".
    //
    // \throws std::invalid_argument if the first line of Buffer is not
    // "", and does not end with SMTPENDL.
    //
    bool getHeaderLine(std::string *HeaderLine);

public:
    MailHeaders();                                                              ///< Constructer for MailHeaders.
    ~MailHeaders();                                                             ///< Destructor for MailHeaders.

    /// Load mail headers.
    //
    // This method loads the object with the headers.
    //
    // \param[in] HeaderBuffer contains the headers.
    //
    void loadHeaders(const string &HeaderBuffer);

    /// Get the next header name and body.
    //
    // This method returns the next header name and body.  The body is
    // formatted so that it can be used as input for the libmilter
    // smfi_addheader() function.
    //
    // \param[out] HeaderName contains the header name.
    //
    // \param[out] FormattedHeaderBody contains the formatted header
    // body.
    //
    // \returns true if a header/body is found, false if the buffer is
    // "".
    //
    // \throws exceptions thrown by getHeaderName and getHeaderLine.
    //
    // \see getHeaderName.
    //
    // \see getHeaderLine.
    //
    bool getNameBody(string *HeaderName, string *FormattedHeaderBody);
};

#endif