#include <iostream>
#include <string_view>
#include <string>
#include "tree.hpp"
#include "utils.hpp"
#include <assert.h>

using std::cerr;
using std::string_view;
using std::string;
using std::vector;
using std::pair;
/* using std::endl; */

namespace /* internal */
{
	struct alloced
	{
		char* const data;
		char* const end;
		alloced(U32 len)
			: data(new char[len])
			, end(data + len)
		{}
		alloced(const alloced&) = delete;
		alloced(alloced&& other)
			: data(other.data)
			, end(other.end)
		{
			const_cast<char*&>(other.data) = nullptr;
		}
		~alloced()
		{
			delete[] data;
		}
	};

	enum TokenType
	{
		ATTRIBUTE,
		STRING,
		/* DATE, */
		NUMBER,
		NEW_LINE,
		SEPARATOR,				/* , */
		REPEAT					/* - */
	};

	struct token
	{
		token(const char* b, const char* e);
		explicit token(TokenType t)
			: type(t)
		 {
		 }

		U32 size() const
		{
			return end - begin;
		}

		const char* begin;
		const char* end;
		TokenType type;
	};

	using TokenIt = vector<token>::const_iterator;

	char* end_data_;				/* past the end pointer */
	unsigned line = 1;
	pair<person_id, person_id> prev_parents(Nobody, Nobody);

	/* state */
	/* void state_neutral(char* it_data); */
	void state_person(TokenIt& it, TokenIt end);
	/* void state_person_attribute() */

	/* result */
	Tree* cur_tree;

	[[noreturn]]void err_unexpected_end()
	{
		endwin();
		cerr << "Unexpected end of file\n";
		cerr.flush();
		exit(1);
	}

	[[noreturn]]void err_unexpected_char(char c)
	{
		endwin();
		cerr << "Line " << line <<  ": Unexpected '" << c << "'\n";
		cerr.flush();
		exit(1);
	}

	[[noreturn]]void err_expected(const char* what, token instead)
	{
		endwin();
		cerr << "Line " << line <<  ": Expected " << what << "got";
		cerr.write(instead.begin, instead.size());
		cerr << "instead\n";
		cerr.flush();
		exit(1);
	}


	[[noreturn]]void err_unexpected_token(token t)
	{
		endwin();
		cerr << "Line " << line <<  ": Unexpected token '";
		cerr.write(t.begin, t.size());
		cerr << "'\n";
		cerr.flush();
		exit(1);
	}

	[[noreturn]]void err_illegal_attribute(token attr)
	{
		endwin();
		cerr << "Line " << line <<  ": Illegal attribute '";
		cerr.write(attr.begin, attr.size());
		cerr << "'\n";
		cerr.flush();
		exit(1);
	}

	/* [[noreturn]]void err_thirdParent(const string& extra_name) */
	/* { */
	/* 	endwin(); */
	/* 	cerr << "Line " << line << ": two parents are already defined, " */
	/* 		 << extra_name << " is third\n"; */
	/* 	cerr.flush(); */
	/* 	exit(1); */
	/* } */

	[[noreturn]]void err_personUndefined(const string& name)
	{
		endwin();
		cerr << "Line " << line << ": '" << name << "' is undefined.\n"
			"Members need to be defined before they are used as relations\n";
		cerr.flush();
		exit(1);
	}

	[[noreturn]]void err_indexExcedes(U32 index, U32 max)
	{
		endwin();
		cerr << "Line " << line << ": '" << index << "' is too large.\n"
			 << "At most the index after a name can be the number of people with the "
			"same name already defined - 1, since the count starts from 0.\n"
			"In this case the max is " << max << '\n';
		cerr.flush();
		exit(1);
	}

	/* void err_name_index(const string& name, U32 i) */
	/* { */
	/* 	endwin(); */
	/* 	cerr << "Line " << line << " the number given after the declaration of a person can" */
	/* 		" only be his place among the same named. " << i << " doesn't satisfy this for '" */
	/* 		 << name << '\'' << endl; */
	/* 	exit(1); */
	/* } */

	bool isNum(char c)
	{
		return c >= '0' && c <= '9';
	}

	TokenType findType(token t)
	{
		TokenType type = NUMBER;
		for(const char* it = t.begin; it < t.end; ++it)
		{
			if(!isNum(*it))
			{
				type = STRING;
				break;
			}
		}

		if(type == STRING)
		{
			if(t.size() == 1)
			{
				switch(t.begin[0])
				{
				case ',':
					type = SEPARATOR;
					break;
				case '-':
					type = REPEAT;
					break;
				case '\n':
					type = NEW_LINE;
				}
			}
			else if(t.size() == 2)
			{
				if(t.begin[1] == ':')
					type = ATTRIBUTE;
			}
		}
		return type;
	}

	token::token(const char* b, const char* e)
		: begin(b)
		, end(e)
	{
		type = findType(*this);
	}


	U32 calcNumber(token t)
	{
		assert(t.type == NUMBER);
		U32 val = 0;
		for(const char* it = t.begin; it < t.end; ++it)
			val = val*10 + *it-'0';

		return val;
	}

	void expect_newline(TokenIt& it)
	{
		if(it->type == NEW_LINE)
		{
			++line;
			++it;
		}
		else
			err_unexpected_token(*it);
	}

	/* construct name from tokens */
	string parseName(TokenIt& it, TokenIt end)
	{
		if(it->type != STRING)
			err_expected("name", *it);

		string name;
		for(; it < end && it->type == STRING; ++it)
		{
			name.append(it->begin, it->end);
			name += ' ';
		}
		name.pop_back();		/* remove last ' ' */
		return name;
	}

	/* find a person's id in the tree based on his name and index
	 * among same named */
	person_id findPerson(const string& name, U32 same_name_index)
	{
		vector<person_id> same_named = cur_tree->findId(name);

		if(same_named.empty())
			err_personUndefined(name);
		else if(same_name_index >= same_named.size())
			err_indexExcedes(same_name_index, same_named.size()-1);
		else
			return same_named[same_name_index];
	}

	U32 sameNamedIndex(TokenIt& it)
	{
		U32 res = 0;
		if(it->type == NUMBER)
		{
			res = calcNumber(*it);
			++it;
		}
		return res;
	}

	Sex parseSex(TokenIt& it, TokenIt end)
	{
		Sex res = M;
		if(it->type == SEPARATOR)
		{
			++it;
			if(it == end)
				err_unexpected_end();

			if(it->type == STRING)
			{
				if(it->size() == 1)
				{
					if(it->begin[0] == 'M')
						res = M;
					else if(it->begin[0] == 'F')
						res = F;
					else
						err_expected("sex", *it);
					++it;
				}
				else
					err_expected("sex", *it);

			}
			else
				err_unexpected_token(*it);
		}

		expect_newline(it);

		return res;
	}

	I32 processDatePart(const char*& it_date, const char* end_date)
	{
		I32 sign = 1;
		I32 val = 0;
		for(; it_date < end_date; ++it_date)
		{
			switch(*it_date)
			{
			case '-':
				sign = -1;
				break;
			case '0' ... '9':
				val = val*10 + (*it_date - '0');
				break;
			case '.':
				if(val == 0)
					err_unexpected_char('.');
				else
					return sign * val;
				break;
				/* case '?': todo */
			default:
				err_unexpected_char(*it_date);
			}
		}
		return sign * val;
	}

	EventTime state_date(TokenIt& it)		/* todo validate  */
	{
		++it;					/* skip attribute */
		if(it->type == STRING || it->type == NUMBER)
		{
			EventTime date;
			const char* it_date = it->begin;
			const char* end_date = it->end;
			date.year = processDatePart(it_date, end_date);
			if(*it_date == '.')
			{
				++it_date;
				date.month = processDatePart(it_date, end_date);

				if(*it_date == '.')
				{
					++it_date;
					date.day = processDatePart(it_date, end_date);
				}
			}

			++it;
			expect_newline(it);
			return date;
		}
		else
			err_expected("date", *it);

	}

	pair<person_id, person_id> processParents(TokenIt& it, TokenIt end)
	{
		++it;					/* skip attribute */

		pair<person_id, person_id> parents(Nobody, Nobody);
		if(it->type == REPEAT)
		{
			parents = prev_parents;
			++it;
		}
		else
		{
			string name = parseName(it, end);
			U32 same_name_index = sameNamedIndex(it);
			parents.first = findPerson(name, same_name_index);
			if(it->type == SEPARATOR)
			{
				++it;
				string name = parseName(it, end);
				U32 same_name_index = sameNamedIndex(it);
				parents.second = findPerson(name, same_name_index);
			}
			prev_parents = parents;
		}

		expect_newline(it);
		return parents;
	}

	vector<person_id> parseSpouses(TokenIt& it, TokenIt end)
	{
		++it;					/* skip attribute */
		vector<person_id> spouses;
		while(true)
		{
			switch(it->type)
			{
			case STRING:
			{
				string name = parseName(it, end); /* todo unify in 1 function */
				U32 same_name_index = sameNamedIndex(it);
				spouses.push_back(findPerson(name, same_name_index));
			}
			break;
			case SEPARATOR:
				++it;
				break;
			case REPEAT:
				++it;
				spouses.push_back( cur_tree->last() );
				break;
			case NEW_LINE:
				++line;
				++it;
				return spouses;
			default:
				err_unexpected_token(*it);
			}
		}
	}

	void state_neutral(const vector<token>& tokens)
	{
		auto end = tokens.cend();
		for(TokenIt it = tokens.cbegin(); it < end;)
		{
			switch(it->type)
			{
			case NEW_LINE:
				++line;
				++it;
				break;
			case STRING:
				state_person(it, end);
				break;
			default:
				err_unexpected_token(*it);

			}
		}
	}

	void state_person(TokenIt& it, TokenIt end)
	{
		pair<person_id, person_id> parents(Nobody, Nobody);
		vector<person_id> spouses;
		EventTime birth{};
		EventTime death{};

		string name = parseName(it, end);

		if(it->type == NUMBER)
			++it;

		/* U32 same_name_index = sameNamedIndex(it); */
		/* todo */
		/* if(cur_tree->findId(name).size() != same_name_index) */
			/* err_name_index(name, same_name_index); */

		Sex sex = parseSex(it, end);

		while(true)
		{
			switch(it->type)
			{
			case ATTRIBUTE:
				switch(it->begin[0])
				{
				case 'b':
					birth = state_date(it); /* todo check for redefinition */
					break;
				case 'd':
					death = state_date(it);
					break;
				case 'p':
					parents = processParents(it, end);
					break;
				case 's':
					spouses = parseSpouses(it, end);
					break;
				default:
					err_illegal_attribute(*it);
				}
				break;
			case NEW_LINE:
				++line;
				++it;
			case STRING:
				/* todo str prevent copy */
				cur_tree->addPerson(name.c_str(), sex,
									parents.first, parents.second, birth, death);
				for(person_id spouse: spouses)
					cur_tree->addRelation(spouse, Spouse, cur_tree->last());
				return;
			default:
				err_unexpected_token(*it);
			}
		}
	}

	alloced removeComments(MappedFile file) /* todo - drop */
	{
		alloced res(file.len);

		char* itres = res.data;
		char* end = file.data + file.len;
		for(char* it = file.data; it < end; ++it)
		{
			if(*it == '#')
			{
				while(++it != end && *it != '\n'); /* skip comment */
				*itres++ = '\n';				   /* add \n */
			}
			else
			{
				*itres = *it;
				++itres;
			}
		}
		end_data_ = itres;
		return res;
	}

	vector<token> tokenize(const char* data_begin, const char* data_end)
	{
		vector<token> tokens;
		tokens.reserve(256);
		const char* token_begin = data_begin;

		for(const char* it = data_begin; it < data_end; ++it)
		{
			switch(*it)
			{
			case ':':
				if(token_begin < it)
					tokens.emplace_back(token_begin, it+1); /* consume the : */
				token_begin = it + 1;
				break;
			case ' ':
			case '\t':
				if(token_begin < it)
					tokens.emplace_back(token_begin, it);
				token_begin = it + 1; /* skip the ws */
				break;
			case ',':
			case '\n':
				if(token_begin < it)
					tokens.emplace_back(token_begin, it);
				tokens.emplace_back(it, it+1);
				token_begin = it+1;
				break;
			/* case '0' ... '9': */

			default: break;
			}
		}
		tokens.emplace_back(NEW_LINE);
		tokens.emplace_back(NEW_LINE);
		return tokens;
	}
}


Tree parseTftFile(const char* path)
{
	fd_t file = openOrDie(path);

	Tree result(path);
	cur_tree = &result;

	MappedFile mapedfile = mapfile(file);
	alloced preprocessed = removeComments(mapedfile);
	vector<token> tokens = tokenize(preprocessed.data, end_data_);

	state_neutral(tokens);

	return result;
}