#include <exception>
#include <string>

#define I18N_PHONENUMBERS_USE_BOOST
#include "phonenumbers/phonenumberutil.h"

extern "C" {
	#include "postgres.h"
	#include "libpq/pqformat.h"
	#include "fmgr.h"
}

using namespace i18n::phonenumbers;

PhoneNumberUtil *phoneUtil = PhoneNumberUtil::GetInstance();

//Utility functions for error handling

void reportOutOfMemory() {
	ereport(ERROR,
		(errcode(ERRCODE_OUT_OF_MEMORY)));
}

void reportParsingError(const char* phone_number, const char* msg = "") {
	ereport(ERROR,
			(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
			 errmsg("unable to parse '%s' as a phone number", phone_number),
			 errdetail("%s", msg)));
}

void reportGenericError(std::exception& exception) {
	ereport(ERROR,
			(errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
			 errmsg("C++ exception: %s", typeid(exception).name()),
			 errdetail("%s", exception.what())));
}

//TODO: handle non-exception thrown types? (shouldn't happen, but you never know...)

extern "C" {
	#ifdef PG_MODULE_MAGIC
		PG_MODULE_MAGIC;
	#endif

	PGDLLEXPORT PG_FUNCTION_INFO_V1(phone_number_in);

	PGDLLEXPORT
	Datum
	phone_number_in(PG_FUNCTION_ARGS)
	{
		const char *str = PG_GETARG_CSTRING(0);
		PhoneNumber *number;

		number = (PhoneNumber*)palloc0(sizeof(PhoneNumber));
		//TODO: can this be removed? (palloc normally handles this, right?)
		if(number == nullptr) {
			reportOutOfMemory();
			PG_RETURN_NULL();
		}

		try {
			using PNU = i18n::phonenumbers::PhoneNumberUtil;
			PNU::ErrorType error;
			error = phoneUtil->Parse(str, "US", number);
			switch(error) {
			case PNU::NO_PARSING_ERROR:
				//The number was parsed correctly; return it.
				PG_RETURN_POINTER(number);
				break;
			case PNU::NOT_A_NUMBER:
				reportParsingError(str, "String does not appear to contain a phone number.");
				break;
			case PNU::INVALID_COUNTRY_CODE_ERROR:
				reportParsingError(str, "Invalid country code");
				break;
			//TODO: handle more error cases specifically.
			default:
				//We have some generic parsing error.
				reportParsingError(str);
			}
			//TODO: check number validity.
		} catch(std::bad_alloc& e) {
			reportOutOfMemory();
		} catch (std::exception& e) {
			reportGenericError(e);
		}

		//If we get here, we couldn't return a valid number.
		PG_RETURN_NULL();
	}

	PGDLLEXPORT PG_FUNCTION_INFO_V1(phone_number_out);

	PGDLLEXPORT
	Datum
	phone_number_out(PG_FUNCTION_ARGS)
	{
		PhoneNumber *number = (PhoneNumber*)PG_GETARG_POINTER(0);
		std::string formatted;
		char *result;

		formatted.resize(20, ' ');

		try {
			phoneUtil->Format(*number, PhoneNumberUtil::INTERNATIONAL, &formatted);
		} catch(std::bad_alloc& e) {
			reportOutOfMemory();
		} catch (std::exception& e) {
			reportGenericError(e);
		}

		//Copy the formatted number to a C-style string.
		//We must use the PostgreSQL allocator, not new/malloc.
		size_t len = formatted.length();
		ereport(INFO,
				(errcode(ERRCODE_SUCCESSFUL_COMPLETION),
				errmsg("Length: %zu", len)));
		result = (char*)palloc(len + 1);
		if(result == nullptr) {
			reportOutOfMemory();
			PG_RETURN_NULL();
		}
		memcpy(result, formatted.data(), len);
		result[len] = '\0';

		PG_RETURN_CSTRING(result);
	}

	PGDLLEXPORT PG_FUNCTION_INFO_V1(phone_number_recv);

	PGDLLEXPORT
	Datum
	phone_number_recv(PG_FUNCTION_ARGS)
	{
		StringInfo buf = (StringInfo)PG_GETARG_POINTER(0);
		PhoneNumber *result;

		//TODO: error handling?
		result = (PhoneNumber*)palloc0(sizeof(PhoneNumber));
		result->set_country_code(pq_getmsgint(buf, 4));
		result->set_national_number(pq_getmsgint64(buf));
		PG_RETURN_POINTER(result);
	}

	PGDLLEXPORT PG_FUNCTION_INFO_V1(phone_number_send);

	PGDLLEXPORT
	Datum
	phone_number_send(PG_FUNCTION_ARGS)
	{
		PhoneNumber *number = (PhoneNumber*)PG_GETARG_POINTER(0);
		StringInfoData buf;

		pq_begintypsend(&buf);
		pq_sendint(&buf, number->country_code(), 4);
		pq_sendint64(&buf, number->national_number());
		PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
	}
}