// MailHeaders.cpp
// Copyright (C) 2008 ARM Research Labs, LLC.
// See www.armresearch.com for the copyright terms.
//
// This file contains the functions to extract the mail header and
// body from the string returned by SNFMilterEngine::XHeaders().

#include <stdexcept>
#include <sstream>
#include "MailHeaders.hpp"

using namespace std;

const string DefaultSMTPENDL = "\r\n";                                          ///< Default SMTP endline.
const string DefaultLibmilterENDL = "\n ";                                      ///< Default libmilter endline.
const string DefaultPrefix = "X-";                                              ///< Default start of header line.

MailHeaders::MailHeaders() :
    SMTPENDL(DefaultSMTPENDL),
    LibMilterENDL(DefaultLibmilterENDL) {
    }

MailHeaders::~MailHeaders() {
}

void
MailHeaders::loadHeaders(const string &HeaderBuffer) {
    Buffer = HeaderBuffer;
}

bool
MailHeaders::getHeaderName(string *HeaderName) {
    if (Buffer.empty()) {                                                       // No header if the buffer is empty.
        return false;
    }
    string::size_type endIndex = Buffer.find(SMTPENDL);
    if (string::npos == endIndex) {                                             // No SMPENDL.
        ostringstream Temp;
        Temp << "Invalid header line (no SMTP end-of-line):  '"
             << Buffer << "'.";
        throw std::invalid_argument(Temp.str());
    }
    string Line(Buffer, 0, endIndex);                                           // First line of the header.
    string::size_type colonIndex = Line.find(":");
    if (string::npos == colonIndex) {                                           // No ":".
        ostringstream Temp;
        Temp << "Invalid header line (no ':'):  '"
             << Buffer << "'.";
        throw std::invalid_argument(Temp.str());
    }
    HeaderName->assign(Line, 0, colonIndex);
    if (0 == HeaderName->size()) {                                              // Null header name.
        ostringstream Temp;
        Temp << "Invalid header line (no name):  '"
             << Buffer << "'.";
        throw std::invalid_argument(Temp.str());
    }
    Buffer.erase(0, colonIndex + 1);                                            // Erase the header name and ":".
    return true;
}

bool
MailHeaders::getHeaderLine(string *HeaderLine) {
    if (Buffer.empty()) {                                                       // No line if the buffer is empty.
        return false;
    }
    string::size_type EndIndex = Buffer.find(SMTPENDL);
    if (string::npos == EndIndex) {                                             // No SMPENDL.
        ostringstream Temp;
        Temp << "Invalid header line (no SMTP end-of-line):  '"
             << Buffer << "'.";
        throw std::invalid_argument(Temp.str());
    }
    HeaderLine->assign(Buffer, 0, EndIndex);                                    // Tentative line of the body.
    string::size_type XIndex = HeaderLine->find("X-");
    if (XIndex == 0) {                                                          // Does it begin with "X-"?
        return false;                                                           // Yes; it's not the body line.
    }

    Buffer.erase(0, EndIndex + SMTPENDL.size());                                // Erase line and SMTPENDL.
    return true;
}

bool
MailHeaders::getNameBody(string *HeaderName, string *FormattedHeaderBody) {
    if (!getHeaderName(HeaderName)) {                                           // Get the header.
        return false;                                                           // No more headers.
    }

    FormattedHeaderBody->clear();
    string HeaderLine;                                                          // One line of the body.
    bool FirstTime = true;
    while (getHeaderLine(&HeaderLine)) {                                        // While this header has lines...
        if (FirstTime) {
            *FormattedHeaderBody = HeaderLine;
            FirstTime = false;
        } else {
            *FormattedHeaderBody += LibMilterENDL;
            *FormattedHeaderBody += HeaderLine;
        }
    }
    return true;
}