/*
   Copyright (C) 2008 - 2015 by Ignacio R. Morelle <shadowm2006@gmail.com>
   Part of the Battle for Wesnoth Project http://www.wesnoth.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY.

   See the COPYING file for more details.
*/

#include "version.hpp"
#include "serialization/string_utils.hpp"
#include "util.hpp"

#include <cassert>
#include <functional>

version_info::version_info()
	: nums_(3,0), special_(""), special_separator_('\0'), sane_(true)
{
}

version_info::version_info(unsigned int major, unsigned int minor, unsigned int revision_level, bool sane,
                           char special_separator, const std::string& special)
	: nums_(3,0), special_(special), special_separator_(special_separator), sane_(sane)
{
	nums_[0] = major;
	nums_[1] = minor;
	nums_[2] = revision_level;
}

version_info::version_info(const std::string& str)
	: nums_(3,0)
	, special_("")
	, special_separator_('\0')
	, sane_(true)
{
	std::string v = str;
	utils::strip(v);

	if(v.empty())
		return;

	//
	// The breakpoint is where the "special" version component begins.
	// For 1.1.2a it would at the index of the char 'a'. For 1.1.4+dev it is at '+'.
	//
	// For 1.5.2 it is at npos.
	//
	const std::string::size_type breakpoint_pos = v.find_first_not_of(".0123456789");
	std::string left_side;
	if(breakpoint_pos != std::string::npos) {
		const std::string right_side = v.substr(breakpoint_pos);
		assert(right_side.empty() == false);

		if((right_side[0] >= 'A' && right_side[0] <= 'Z') || (right_side[0] >= 'a' && right_side[0] <= 'z')) {
			special_separator_ = '\0';
			special_ = right_side;
		}
		else {
			special_separator_ = right_side[0];
			if(right_side.size() > 1) {
				special_ = right_side.substr(1);
			}
		}

		left_side = v.substr(0, breakpoint_pos);
	}
	else {
		left_side = v;
	}

	const std::vector<std::string> components = utils::split(left_side, '.');
	const size_t s = components.size();
	if(s == 0) {
		return;
	}
	else if(s > 3) {
		nums_.resize(s, 0);
	}

	try {
		for(size_t i = 0; (i < s); ++i) {
			nums_[i] = lexical_cast<unsigned int>(components[i]);
		}
	}
	catch(bad_lexical_cast const&) {
		// FIXME: actually, this is virtually impossible to occur
		// due to the find_first_not_of() call above...
		sane_ = false;
	}
}

std::string version_info::str() const
{
	const size_t s = nums_.size();

	std::ostringstream o;
	for(size_t k = 0; k < s; ++k) {
		o << nums_[k];

		if(s != 1+k) {
			o << '.';
		}
	}

	if(! special_.empty()) {
		if(special_separator_ != '\0') {
			o << special_separator_;
		}

		o << special_;
	}

	return o.str();
}

void version_info::set_major_version(unsigned int v) {
	nums_[0] = v;
}

void version_info::set_minor_version(unsigned int v) {
	nums_[1] = v;
}

void version_info::set_revision_level(unsigned int v) {
	nums_[2] = v;
}

unsigned int version_info::major_version() const {
	return nums_[0];
}

unsigned int version_info::minor_version() const {
	return nums_[1];
}

unsigned int version_info::revision_level() const {
	return nums_[2];
}

bool version_info::is_canonical() const {
	return nums_.size() <= 3 && sane_;
}

namespace {
	enum COMP_TYPE {
		EQUAL,
		NOT_EQUAL,
		LT, GT
	};

	/*
	           x         >          y
	x0.x1.x2.x3.[...].xN > y0.y1.y2.y3.[...].yN iff

	x0 > y0 || (x0 == y0 && (x1 > y1 || (x1 == y1 && (x2 > y2 || (x2 >= y2 ||

	*/
	template<typename _Toperator, typename _Tfallback_operator>
	bool recursive_order_operation(const std::vector<unsigned int>& l, const std::vector<unsigned int>& r, size_t k)
	{
		if(k >= l.size() || k >= r.size()) {
			return false;
		}

		unsigned int const& lvalue = l[k];
		unsigned int const& rvalue = r[k];

		_Toperator o;
		_Tfallback_operator fallback_o;

		bool ret = o(lvalue, rvalue);
		if((!ret) && fallback_o(lvalue, rvalue)) {
			ret = recursive_order_operation<_Toperator, _Tfallback_operator>(l,r,++k);
		}
		return ret;
	}

#ifdef _MSC_VER
#pragma warning (push)
#pragma warning (disable: 4706)
#endif
	bool version_numbers_comparison_internal(const version_info& l, const version_info& r, COMP_TYPE o)
	{
		if((!l.good()) || !r.good()) throw version_info::not_sane_exception();

		std::vector<unsigned int> lc = l.components();
		std::vector<unsigned int> rc = r.components();

		const size_t lsize = lc.size();
		const size_t rsize = rc.size();
		const size_t csize = std::max(lsize, rsize);

		// make compatible, missing items default to zero
		if(lsize < csize) lc.resize(csize, 0);
		if(rsize < csize) rc.resize(csize, 0);

		bool result = true;

		const std::vector<unsigned int>& lcc = lc;
		const std::vector<unsigned int>& rcc = rc;

		switch(o)
		{
			case EQUAL: case NOT_EQUAL: {
				for(size_t i = 0; i < csize; ++i) {
					unsigned int const& lvalue = lc[i];
					unsigned int const& rvalue = rc[i];
					if(o == NOT_EQUAL) {
						if((result = (lvalue != rvalue))) {
#ifdef _MSC_VER
#pragma warning (pop)
#endif
							return true;
						}
						continue;
					} else {
						result = result && lvalue == rvalue;
						if(!result) {
							break;
						}
					}
				}
				break;
			}
			case LT:
				result = recursive_order_operation<std::less<unsigned int>, std::equal_to<unsigned int> >(lcc, rcc, 0);
				break;
			case GT:
				result = recursive_order_operation<std::greater<unsigned int>, std::equal_to<unsigned int> >(lcc, rcc, 0);
				break;
			default:
				assert(0 == 1);
				break;
		}
		return result;
	}

} // end unnamed namespace

bool operator==(const version_info& l, const version_info& r)
{
	return version_numbers_comparison_internal(l, r, EQUAL) && l.special_version() == r.special_version();
}

bool operator!=(const version_info& l, const version_info& r)
{
	return version_numbers_comparison_internal(l, r, NOT_EQUAL) || l.special_version() != r.special_version();
}

bool operator<(const version_info& l, const version_info& r)
{
	return version_numbers_comparison_internal(l, r, LT) || (
		version_numbers_comparison_internal(l, r, EQUAL) && (
			(l.special_version().empty() && !r.special_version().empty()) ||
			(l.special_version() < r.special_version())
		)
	);
}

bool operator>(const version_info& l, const version_info& r)
{
	return version_numbers_comparison_internal(l, r, GT) || (
		version_numbers_comparison_internal(l, r, EQUAL) && (
			(r.special_version().empty() && !l.special_version().empty()) ||
			(l.special_version() > r.special_version())
		)
	);
}

bool operator<=(const version_info& l, const version_info& r)
{
	return l < r || l == r;
}

bool operator>=(const version_info& l, const version_info& r)
{
	return l > r || l == r;
}

VERSION_COMP_OP parse_version_op(const std::string& op_str)
{
	if(op_str == "==") {
		return OP_EQUAL;
	} else if(op_str == "!=") {
		return OP_NOT_EQUAL;
	} else if(op_str == "<") {
		return OP_LESS;
	} else if(op_str == "<=") {
		return OP_LESS_OR_EQUAL;
	} else if(op_str == ">") {
		return OP_GREATER;
	} else if(op_str == ">=") {
		return OP_GREATER_OR_EQUAL;
	}

	return OP_INVALID;
}

bool do_version_check(const version_info& a, VERSION_COMP_OP op, const version_info& b)
{
	switch(op) {
	case OP_EQUAL:
		return a == b;
	case OP_NOT_EQUAL:
		return a != b;
	case OP_LESS:
		return a < b;
	case OP_LESS_OR_EQUAL:
		return a <= b;
	case OP_GREATER:
		return a > b;
	case OP_GREATER_OR_EQUAL:
		return a >= b;
	default:
		;
	}

	return false;
}