#include <exception>
#include <string>

#include "phonenumbers/phonenumberutil.h"

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

#include "short_phone_number.h"

using namespace i18n::phonenumbers;

static const PhoneNumberUtil* const phoneUtil = PhoneNumberUtil::GetInstance();

static const char* parseErrorMessage(PhoneNumberUtil::ErrorType error) {
	using PNU = i18n::phonenumbers::PhoneNumberUtil;
	switch(error) {
	case PNU::NO_PARSING_ERROR:
		return "Parsed successfully";
	case PNU::NOT_A_NUMBER:
		return "String does not appear to contain a phone number.";
	case PNU::INVALID_COUNTRY_CODE_ERROR:
		return "Invalid country code";
	//TODO: handle more error cases specifically.
	default:
		//We have some generic parsing error.
		return "Unable to parse number";
	}
}

/*
 * Utility functions for error handling
 */

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

static void reportParseError(const char* phone_number, PhoneNumberUtil::ErrorType err) {
	ereport(ERROR,
			(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
			 errmsg("unable to parse '%s' as a phone number", phone_number),
			 errdetail("%s", parseErrorMessage(err))));
}

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

static void logInfo(const char* msg) {
	ereport(INFO,
			(errcode(ERRCODE_SUCCESSFUL_COMPLETION),
			errmsg("%s", msg)));
}

/*
 * Utility functions
 */

//Internal function used by phone_number_in and parse_phone_number
ShortPhoneNumber* parsePhoneNumber(const char* number_str, const char* country) throw() {
	try {
		PhoneNumber number;
		ShortPhoneNumber* short_number;

		short_number = (ShortPhoneNumber*)palloc0(sizeof(ShortPhoneNumber));
		if(short_number == nullptr) {
			throw std::bad_alloc();
		}

		PhoneNumberUtil::ErrorType error;
		error = phoneUtil->Parse(number_str, country, &number);
		if(error == PhoneNumberUtil::NO_PARSING_ERROR) {
			//Initialize short_number using placement new.
			new(short_number) ShortPhoneNumber(number);
			return short_number;
		} else {
			reportParseError(number_str, error);
			return nullptr;
		}
		//TODO: check number validity.
	} catch(std::bad_alloc& e) {
		reportOutOfMemory();
	} catch (std::exception& e) {
		reportGenericError(e);
	}

	return nullptr;
}

//TODO: handle non-exception thrown types? (shouldn't happen, but you never know...)
//TODO: check null args? (PG_ARGISNULL). Make non-strict?

/*
 * Extension functions
 */

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 *number_str = PG_GETARG_CSTRING(0);

		ShortPhoneNumber* number = parsePhoneNumber(number_str, "US");
		if(number) {
			PG_RETURN_POINTER(number);
		} else {
			PG_RETURN_NULL();
		}
	}
	
	PGDLLEXPORT PG_FUNCTION_INFO_V1(parse_phone_number);

	PGDLLEXPORT
	Datum
	parse_phone_number(PG_FUNCTION_ARGS)
	{
		const char *number_str = PG_GETARG_CSTRING(0);
		const char *country = PG_GETARG_CSTRING(1);

		ShortPhoneNumber* number = parsePhoneNumber(number_str, country);
		if(number) {
			PG_RETURN_POINTER(number);
		} else {
			PG_RETURN_NULL();
		}
	}

	PGDLLEXPORT PG_FUNCTION_INFO_V1(phone_number_out);

	PGDLLEXPORT
	Datum
	phone_number_out(PG_FUNCTION_ARGS)
	{
		try {
			const ShortPhoneNumber* short_number = (ShortPhoneNumber*)PG_GETARG_POINTER(0);
			PhoneNumber number = *short_number;

			std::string formatted;
			phoneUtil->Format(number, PhoneNumberUtil::INTERNATIONAL, &formatted);

			//Copy the formatted number to a C-style string.
			//We must use the PostgreSQL allocator, not new/malloc.
			size_t len = formatted.length();
			char* result = (char*)palloc(len + 1);
			if(result == nullptr) {
				throw std::bad_alloc();
			}
			memcpy(result, formatted.data(), len);
			result[len] = '\0';

			PG_RETURN_CSTRING(result);
		} catch(std::bad_alloc& e) {
			reportOutOfMemory();
		} catch (std::exception& e) {
			reportGenericError(e);
		}

		PG_RETURN_NULL();
	}

	PGDLLEXPORT PG_FUNCTION_INFO_V1(phone_number_recv);

	//TODO: handle leading zeroes?
	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));
	}
}