#include <cstddef>

#include <iostream>
#include <exception>

#include <boost/lexical_cast.hpp>
#include <boost/asio/ip/network_v6.hpp>

#include <Alepha/IOStreams/Streamable.h>
#include <Alepha/IOStreams/String.h>

namespace asio= boost::asio;
namespace ip= asio::ip;

using Alepha::IOStreams::Str;

template< typename= Alepha::Capabilities< Alepha::IOStreams::Streamable > >
struct Allocation_core;

using Allocation= Allocation_core<>;

struct IP_Address : ip::network_v6
{
	using ip::network_v6::network_v6;

	IP_Address( const network_v6 &n ) : ip::network_v6( n ) {}

	friend std::istream &
	operator >> ( std::istream &is, IP_Address &a )
	{
		std::string s;
		is >> s;
		std::cerr << "Network string: " << s << std::endl;
		if( not s.contains( '/' ) )
		{
			throw std::runtime_error{ "No subnet mask detected.  Did you forget a `/`?" };
		}
		a= ip::make_network_v6( s );
		std::cerr << "Parsed into: `" << a << std::endl;

		return is;
	}
};

template< typename >
struct Allocation_core
{
	IP_Address network;

	std::string owner;
	std::string name;
	std::string purpose;

	std::string country;
	std::string region;
	std::string city;
	std::string postal;

	std::vector< Allocation > subAllocations() const;
	std::vector< Allocation > available() const;
};

std::vector< Allocation > spaces;


template<>
inline std::vector< Allocation >
Allocation::subAllocations() const
{
	std::vector< Allocation > rv;

	for( const auto &alloc: spaces )
	{
		if( alloc.network.is_subnet_of( network ) ) rv.push_back( alloc );
	}

	return rv;
}

struct Command
{
	std::string name;
	std::string help;
	std::function< void ( std::vector< std::string > ) > run;
};
	

std::map< std::string, Command > commands;

void
add_command( Command command )
{
	commands.insert( { command.name, command } );
}

int
main()
try
{
	spaces.push_back( { ip::make_network_v6( "2000::/3" ), "IANA", "Global Routing - v6", "The initial global routing table for v6" } );

	spaces.push_back( { ip::make_network_v6( "2600::/8" ), "ARIN", "ARIN v6 RIR Allocation", "Large ARIN block." } );

	spaces.push_back( { ip::make_network_v6( "2602:f6a8::/36" ), "IMP-NET", "Imperial Network", "Main Imperial Network Allocation." } );

	add_command
	(
		{
			"help",
			"List all commands",
			[]( ... )
			{
				for( const auto &[ name, command ]: commands )
				{
					std::cout << name << " - " << command.help << std::endl;
				}
			}
		}
	);

	add_command
	(
		{
			"quit",
			"Exits the IP Address Manager",
			[]( ... )
			{
				::exit( EXIT_SUCCESS );
			}
		}
	);

	add_command
	(
		{
			"describe",
			"Describe a network range",
			[]( const std::vector< std::string > &args )
			{
				if( args.empty() ) throw std::runtime_error{ "Requires one argument." };
				if( args.size() != 1 ) throw std::runtime_error{ "Too many arguments." };

				const auto &network= boost::lexical_cast< IP_Address >( args.at( 0 ) );
				std::cout << "Parsed: `" << network << "` -- it has a " << network.prefix_length()
						<< " bit mask." << std::endl;

				const Allocation *p= nullptr;

				std::optional< IP_Address > found;
				auto better= [&]( const auto &where )
				{
					return not found.has_value() or where.is_subnet_of( found.value() );
				};

				for( const auto &space: spaces )
				{
					const auto &[ where, owner, name, purpose, country, state, city, postal ]= space;
					std::cerr << "Checking " << network << " against: " << where;
					if( network == where )
					{
						std::cerr << " -- Exact match!" << std::endl;
						found= where;
						p= &space;
						break;
					}
					if( network.is_subnet_of( where ) and better( where ) )
					{
						std::cerr << " -- Matched." << std::endl;
						found= where;
						p = &space;
					}
					else std::cerr << " -- No match." << std::endl;
				}
				std::cout << network << " was best matched by " << found.value() << std::endl;

				const auto &[ _, owner, name, purpose, country, state, city, postal ]= *p;

				std::cout << network << " is owned by " << owner << std::endl;
				std::cout << "It is called `" << name << "`" << std::endl;
				std::cout << "It is used for '" << purpose << "'" << std::endl;
			}
		}
	);

	add_command
	(
		{
			"subnets",
			"Describe a network range's subnets",
			[]( const std::vector< std::string > &args )
			{
				if( args.empty() ) throw std::runtime_error{ "Requires one argument." };
				if( args.size() != 1 ) throw std::runtime_error{ "Too many arguments." };

				const auto &network= boost::lexical_cast< IP_Address >( args.at( 0 ) );
				std::cout << "Parsed: `" << network << "` -- it has a " << network.prefix_length()
						<< " bit mask." << std::endl;

				const Allocation *p= nullptr;

				std::optional< IP_Address > found;
				auto better= [&]( const auto &where )
				{
					return not found.has_value() or where.is_subnet_of( found.value() );
				};

				for( const auto &space: spaces )
				{
					const auto &[ where, owner, name, purpose, country, state, city, postal ]= space;
					if( network.is_subnet_of( where ) and better( where ) )
					{
						found= where;
						p = &space;
					}
				}
				std::cout << network << " was best matched by " << found.value() << std::endl;

				const auto &[ _, owner, name, purpose, country, state, city, postal ]= *p;

				std::cout << network << " is owned by " << owner << std::endl;
				std::cout << "It is called `" << name << "`" << std::endl;
				std::cout << "It is used for '" << purpose << "'" << std::endl;

				for( const auto &sub: p->subAllocations() )
				{
					std::cout << sub.network << ": " << owner << std::endl;
				}
			}
		}
	);

				

	while( not std::cin.eof() )
	try
	{
		std::string line; 
		getline( std::cin, line );

		const auto parsed= Alepha::split( line, ' ' );
		const auto &command= parsed.at( 0 );
		auto args= parsed;
		args.erase( begin( args ) );

		if( command.empty() ) continue;
		if( not commands.contains( command ) )
		{
			throw std::runtime_error{ Str << "No such command `" << command << '`' };
		}
		commands.at( command ).run( args );
	}
	catch( const std::exception &e )
	{
		std::cerr << "ERROR: " << e.what() << std::endl;
	}

	return EXIT_SUCCESS;
}
catch( const std::exception &ex )
{
	std::cerr << "FATAL ERROR: " << ex.what() << std::endl;
	return EXIT_FAILURE;
}