#pragma once

#include <unordered_map>
#include <vector>
#include <string>
#include <iostream>
#include <exception>

#include "bufio.h"

struct BXParseError: std::exception {
	BXParseError(std::string msg): message(msg) {}
	std::string message;

	const char *what() const noexcept override {
		return message.c_str();
	}
};

using BXVariables = std::unordered_map<std::string, std::vector<std::string>>;

class BXParser {
public:
	static const int FLAG_NONE = 0;
	static const int FLAG_ONE_LINE = 1 << 0;

	BXParser(std::istream &stream, int flags, int line = 1, int ch = 1):
		flags_(flags), line_(line), ch_(ch), buf_(stream) {}

	void parse(BXVariables &vars);
	void parseList(const BXVariables &vars, std::vector<std::string> &values);

	int get();
	int peek();
	int peek2();
	void skip(char expected);
	void skip() { get(); }

	int line() const { return line_; }
	int ch() const { return ch_; }

private:
	enum class Operator {
		COLON_EQUALS,
		PLUS_EQUALS,
		EQUALS_PLUS,
		NONE,
	};

	[[noreturn]] void error(std::string);

	Operator readOperator();
	void skipWhitespaceLine();
	void skipWhitespace();

	char parseEscape();
	void parseExpansion(const BXVariables &vars, std::vector<std::string> &values);
	void parseQuotedExpansion(const BXVariables &vars, std::string &content);
	void parseQuotedString(const BXVariables &vars, std::string &content);
	bool parseString(const BXVariables &vars, std::string &content, int sep = -1);
	bool parseIdentifier(std::string &content);

	int flags_;
	int line_;
	int ch_;

	bufio::IBuf<> buf_;
};

class BXWriter {
public:
	BXWriter(std::ostream &stream): buf_(stream) {}

	void write(const BXVariables &vars);

private:
	void newline();
	void escape(const std::string &str);

	bufio::OBuf<> buf_;
};