#include "tparser.h"
#include "tgrammar.h"
#include "ttokenizer.h"
#include "tutil.h"

#include <iostream>

namespace TSyntax
{

//-------------------------------------------------------------------
// RunningPattern
//-------------------------------------------------------------------

class RunningPattern
{
public:
	std::vector<Token> m_tokens;
	const Pattern *m_pattern;

	RunningPattern(const Pattern *pattern) : m_pattern(pattern) {}

	int getPriority() const { return m_pattern->getPriority(); }
	bool isFinished(const Token &token) const { return m_pattern->isFinished(m_tokens, token); }
	bool isComplete(const Token &token) const { return m_pattern->isComplete(m_tokens, token); }
	bool expressionExpected() const { return m_pattern->expressionExpected(m_tokens); }
	bool matchToken(const Token &token) const { return m_pattern->matchToken(m_tokens, token); }
	void advance()
	{
		assert(!isFinished(Token()));
		m_tokens.push_back(Token());
	}
	void advance(const Token &token)
	{
		assert(!isFinished(token));
		m_tokens.push_back(token);
	}
	TokenType getTokenType(const Token &token) const { return m_pattern->getTokenType(m_tokens, token); }

	void createNode(Calculator *calc, std::vector<CalculatorNode *> &stack)
	{
		m_pattern->createNode(calc, stack, m_tokens);
	}
};

//-------------------------------------------------------------------
// Parser::Imp
//-------------------------------------------------------------------

class Parser::Imp
{
public:
	const Grammar *m_grammar;
	Tokenizer m_tokenizer;
	string m_errorString;
	bool m_isValid;
	Calculator *m_calculator;
	std::vector<RunningPattern> m_patternStack;
	std::vector<CalculatorNode *> m_nodeStack;
	std::vector<SyntaxToken> m_syntaxTokens;
	Grammar::Position m_position;
	// Pattern *m_lastPattern;

	Imp(const Grammar *grammar)
		: m_grammar(grammar), m_errorString(""), m_isValid(false), m_calculator(0), m_position(Grammar::ExpressionStart)
	{
	}
	~Imp()
	{
		clearPointerContainer(m_nodeStack);
		delete m_calculator;
	}

	void pushSyntaxToken(TokenType type);
	bool parseExpression(bool checkOnly);
	void flushPatterns(int minPriority, int minIndex, bool checkOnly);
	bool checkSyntax(std::vector<SyntaxToken> &tokens);
};

//-------------------------------------------------------------------
// Parser
//-------------------------------------------------------------------

Parser::Parser(const Grammar *grammar)
	: m_imp(new Imp(grammar))
{
}

//-------------------------------------------------------------------

Parser::~Parser()
{
}

//-------------------------------------------------------------------

void Parser::Imp::flushPatterns(int minPriority, int minIndex, bool checkOnly)
{
	while ((int)m_patternStack.size() > minIndex && m_patternStack.back().getPriority() >= minPriority) {
		if (!checkOnly)
			m_patternStack.back().createNode(m_calculator, m_nodeStack);
		m_patternStack.pop_back();
	}
}

//-------------------------------------------------------------------

void Parser::Imp::pushSyntaxToken(TokenType type)
{
	SyntaxToken syntaxToken;
	Token token = m_tokenizer.getToken();
	syntaxToken.m_pos = token.getPos();
	syntaxToken.m_length = token.getPos1() - token.getPos() + 1;
	syntaxToken.m_type = type;
	m_syntaxTokens.push_back(syntaxToken);
}

//-------------------------------------------------------------------

bool Parser::Imp::parseExpression(bool checkOnly)
{
	if (!m_grammar)
		return false;
	int stackMinIndex = m_patternStack.size();
	int count = 0;
	Grammar::Position position = Grammar::ExpressionStart;
	m_position = position;
	// warning: parseExpression() is called recursively. m_position is used after parseExpression()
	// for diagnostic and suggestions. position is used in the actual parsing

	bool expressionExpected = true;
	while (!m_tokenizer.eos()) {
		// token, position -> pattern
		const Pattern *pattern = m_grammar->getPattern(position, m_tokenizer.getToken());
		if (!pattern) {
			// no pattern found for the next token
			if (position == Grammar::ExpressionEnd) {
				// already found an expression
				flushPatterns(-1, stackMinIndex, checkOnly);
				return true;
			} else {
				// syntax error : expression not found
				if (checkOnly)
					pushSyntaxToken(UnexpectedToken);

				m_errorString = "Unexpected token";
				return false;
			}
		}
		// pattern found: start scanning it
		RunningPattern runningPattern(pattern);
		if (position == Grammar::ExpressionEnd) // patterns of the form "<expr> ...."
			runningPattern.advance();

		// eat the first token
		if (checkOnly)
			pushSyntaxToken(runningPattern.getTokenType(m_tokenizer.getToken()));
		runningPattern.advance(m_tokenizer.getToken());
		m_tokenizer.nextToken();
		expressionExpected = false;

		while (!runningPattern.isFinished(m_tokenizer.getToken())) {
			if (runningPattern.expressionExpected()) {
				// expression expected
				runningPattern.advance();
				if (runningPattern.isFinished(m_tokenizer.getToken())) {
					// pattern ended with an expression
					expressionExpected = true;
					break;
				}
				// parse a sub expression
				if (!parseExpression(checkOnly)) {
					return false;
				}
			} else {
				// "terminal" expected
				if (m_tokenizer.eos()) {
					// EOS
					if (runningPattern.isComplete(Token()))
						break;
					if (checkOnly)
						pushSyntaxToken(Eos);

					m_errorString = "Uncompleted syntax";
					return false;
				}
				if (!runningPattern.matchToken(m_tokenizer.getToken())) {
					// token mismatch
					if (runningPattern.isComplete(m_tokenizer.getToken()))
						break;
					if (checkOnly)
						pushSyntaxToken(Mismatch);
					m_errorString = "Syntax error";
					return false;
				}
				// token matched
				if (checkOnly)
					pushSyntaxToken(runningPattern.getTokenType(m_tokenizer.getToken()));
				runningPattern.advance(m_tokenizer.getToken());
				m_tokenizer.nextToken();
			}
		}

		// pattern ended
		if (expressionExpected) {
			// pattern terminated with an expression
			if (position == Grammar::ExpressionEnd) {
				// "E op . E"
				flushPatterns(runningPattern.getPriority(), stackMinIndex, checkOnly);
				m_patternStack.push_back(runningPattern);
			} else {
				// "op . E"
				m_patternStack.push_back(runningPattern);
			}
			m_position = position = Grammar::ExpressionStart;
		} else {
			// pattern terminates with a keyword
			if (position == Grammar::ExpressionEnd) {
				// "E op ."
				flushPatterns(runningPattern.getPriority(), stackMinIndex, checkOnly);
			} else {
				// "leaf .", "f(E) .", "(E) ."
			}
			if (!checkOnly)
				runningPattern.createNode(m_calculator, m_nodeStack);
			count++;
			m_position = position = Grammar::ExpressionEnd;
		}
	}
	if (count == 0 || expressionExpected) {

		m_errorString = "Expression expected";
		return false;
	}
	flushPatterns(-1, stackMinIndex, checkOnly);
	return true;
}

//-------------------------------------------------------------------

Calculator *Parser::parse(string text)
{
	m_imp->m_tokenizer.setBuffer(text);
	clearPointerContainer(m_imp->m_nodeStack);
	m_imp->m_errorString = "";
	m_imp->m_isValid = false;
	m_imp->m_calculator = new Calculator();
	bool ret = m_imp->parseExpression(false);
	if (ret && !m_imp->m_nodeStack.empty()) {
		m_imp->m_calculator->setRootNode(m_imp->m_nodeStack.back());
		m_imp->m_nodeStack.pop_back();
		m_imp->m_isValid = true;
	} else {
		delete m_imp->m_calculator;
		m_imp->m_calculator = 0;
	}
	clearPointerContainer(m_imp->m_nodeStack);
	Calculator *calculator = m_imp->m_calculator;
	m_imp->m_calculator = 0;
	return calculator;
}

//-------------------------------------------------------------------

Parser::SyntaxStatus Parser::checkSyntax(std::vector<SyntaxToken> &tokens, string text)
{
	m_imp->m_tokenizer.setBuffer(text);
	if (m_imp->m_tokenizer.eos())
		return Incomplete;
	bool ret = m_imp->parseExpression(true);
	tokens = m_imp->m_syntaxTokens;
	if (ret && m_imp->m_tokenizer.eos())
		return Correct;
	if (tokens.empty())
		return Incomplete;
	SyntaxToken &lastToken = tokens.back();
	if (lastToken.m_type == Eos)
		return Incomplete;

	int k = lastToken.m_pos + lastToken.m_length;
	if (k >= (int)text.length()) {
		if (lastToken.m_type < Unknown) {
			lastToken.m_type = Unknown;
		}
		return ExtraIgnored;
	}

	SyntaxToken extraIgnored;
	extraIgnored.m_type = Unknown;
	extraIgnored.m_pos = k;
	extraIgnored.m_length = text.length() - k;
	tokens.push_back(extraIgnored);

	return Error;
}

//-------------------------------------------------------------------

void Parser::getSuggestions(Grammar::Suggestions &suggestions, string text)
{
	std::vector<SyntaxToken> tokens;
	Parser::SyntaxStatus status = checkSyntax(tokens, text);
	suggestions.clear();
	if (status == Correct || status == Incomplete || status == ExtraIgnored)
		m_imp->m_grammar->getSuggestions(suggestions, m_imp->m_position);
}

//-------------------------------------------------------------------

string Parser::getCurrentPatternString(string text)
{
	return "ohime";
}

//-------------------------------------------------------------------

bool Parser::isValid() const
{
	return m_imp->m_isValid;
}

//-------------------------------------------------------------------

string Parser::getText() const
{
	return m_imp->m_tokenizer.getBuffer();
}

//-------------------------------------------------------------------

string Parser::getError() const
{
	return m_imp->m_errorString;
}

//-------------------------------------------------------------------

std::pair<int, int> Parser::getErrorPos() const
{
	if (m_imp->m_errorString == "")
		return std::make_pair(0, -1);
	Token token = m_imp->m_tokenizer.getToken();
	return std::make_pair(token.getPos(), token.getPos1());
}

//-------------------------------------------------------------------

} // namespace TSyntax