#include "HttpRequestParser.h"
#include "HttpRequest.h"


namespace Http {

HttpRequestParser::HttpRequestParser() :
	m_state(State::MethodStart)
{
}

void HttpRequestParser::Reset()
{
	m_state = State::MethodStart;
}

Utilities::Tribool HttpRequestParser::Consume(HttpRequest& request, char input)
{
	switch (m_state)
	{
	case State::MethodStart:
		if (!IsChar(input) || IsCtl(input) || IsTSpecial(input))
		{
			return false;
		}
		else
		{
			m_state = State::Method;
			request.method.push_back(input);
			return Utilities::Tribool::Indeterminate;
		}
	case State::Method:
		if (input == ' ')
		{
			m_state = State::URI;
			return Utilities::Tribool::Indeterminate;
		}
		else if (!IsChar(input) || IsCtl(input) || IsTSpecial(input))
		{
			return false;
		}
		else
		{
			request.method.push_back(input);
			return Utilities::Tribool::Indeterminate;
		}
	case State::URI:
		if (input == ' ')
		{
			m_state = State::HttpVersionH;
			return Utilities::Tribool::Indeterminate;
		}
		else if (IsCtl(input))
		{
			return false;
		}
		else
		{
			request.uri.push_back(input);
			return Utilities::Tribool::Indeterminate;
		}
	case State::HttpVersionH:
		if (input == 'H')
		{
			m_state = State::HttpVersionT1;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HttpVersionT1:
		if (input == 'T')
		{
			m_state = State::HttpVersionT2;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HttpVersionT2:
		if (input == 'T')
		{
			m_state = State::HttpVersionP;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HttpVersionP:
		if (input == 'P')
		{
			m_state = State::HttpVersionSlash;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HttpVersionSlash:
		if (input == '/')
		{
			request.httpVersionMajor = 0;
			request.httpVersionMinor = 0;
			m_state = State::HttpVersionMajorStart;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HttpVersionMajorStart:
		if (IsDigit(input))
		{
			request.httpVersionMajor = request.httpVersionMajor * 10 + input - '0';
			m_state = State::HttpVersionMajor;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HttpVersionMajor:
		if (input == '.')
		{
			m_state = State::HttpVersionMinorStart;
			return Utilities::Tribool::Indeterminate;
		}
		else if (IsDigit(input))
		{
			request.httpVersionMajor = request.httpVersionMajor * 10 + input - '0';
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HttpVersionMinorStart:
		if (IsDigit(input))
		{
			request.httpVersionMinor = request.httpVersionMinor * 10 + input - '0';
			m_state = State::HttpVersionMinor;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HttpVersionMinor:
		if (input == '\r')
		{
			m_state = State::ExpectingNewline1;
			return Utilities::Tribool::Indeterminate;
		}
		else if (IsDigit(input))
		{
			request.httpVersionMinor = request.httpVersionMinor * 10 + input - '0';
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::ExpectingNewline1:
		if (input == '\n')
		{
			m_state = State::HeaderLineStart;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HeaderLineStart:
		if (input == '\r')
		{
			m_state = State::ExpectingNewline3;
			return Utilities::Tribool::Indeterminate;
		}
		else if (!request.headers.empty() && (input == ' ' || input == '\t'))
		{
			m_state = State::HeaderLws;
			return Utilities::Tribool::Indeterminate;
		}
		else if (!IsChar(input) || IsCtl(input) || IsTSpecial(input))
		{
			return false;
		}
		else
		{
			request.headers.push_back(HttpHeader());
			request.headers.back().name.push_back(input);
			m_state = State::HeaderName;
			return Utilities::Tribool::Indeterminate;
		}
	case State::HeaderLws:
		if (input == '\r')
		{
			m_state = State::ExpectingNewline2;
			return Utilities::Tribool::Indeterminate;
		}
		else if (input == ' ' || input == '\t')
		{
			return Utilities::Tribool::Indeterminate;
		}
		else if (IsCtl(input))
		{
			return false;
		}
		else
		{
			m_state = State::HeaderValue;
			request.headers.back().value.push_back(input);
			return Utilities::Tribool::Indeterminate;
		}
	case State::HeaderName:
		if (input == ':')
		{
			m_state = State::SpaceBeforeHeaderValue;
			return Utilities::Tribool::Indeterminate;
		}
		else if (!IsChar(input) || IsCtl(input) || IsTSpecial(input))
		{
			return false;
		}
		else
		{
			request.headers.back().name.push_back(input);
			return Utilities::Tribool::Indeterminate;
		}
	case State::SpaceBeforeHeaderValue:
		if (input == ' ')
		{
			m_state = State::HeaderValue;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::HeaderValue:
		if (input == '\r')
		{
			m_state = State::ExpectingNewline2;
			return Utilities::Tribool::Indeterminate;
		}
		else if (IsCtl(input))
		{
			return false;
		}
		else
		{
			request.headers.back().value.push_back(input);
			return Utilities::Tribool::Indeterminate;
		}
	case State::ExpectingNewline2:
		if (input == '\n')
		{
			m_state = State::HeaderLineStart;
			return Utilities::Tribool::Indeterminate;
		}
		else
		{
			return false;
		}
	case State::ExpectingNewline3:
		return (input == '\n');
	default:
		return false;
	}
}

bool HttpRequestParser::IsChar(int c)
{
	return c >= 0 && c <= 127;
}

bool HttpRequestParser::IsCtl(int c)
{
	return (c >= 0 && c <= 31) || (c == 127);
}

bool HttpRequestParser::IsTSpecial(int c)
{
	switch (c)
	{
	case '(': case ')': case '<': case '>': case '@':
	case ',': case ';': case ':': case '\\': case '"':
	case '/': case '[': case ']': case '?': case '=':
	case '{': case '}': case ' ': case '\t':
		return true;
	default:
		return false;
	}
}

bool HttpRequestParser::IsDigit(int c)
{
	return c >= '0' && c <= '9';
}

} // namespace Http