/*
 * pg_column_map.c - PG::ColumnMap class extension
 * $Id$
 *
 */

#include "pg.h"
#include "pg_util.h"
#ifdef HAVE_INTTYPES_H
#include <inttypes.h>
#endif

VALUE rb_mPG_BinaryEncoder;
static ID s_id_year;
static ID s_id_month;
static ID s_id_day;


/*
 * Document-class: PG::BinaryEncoder::Boolean < PG::SimpleEncoder
 *
 * This is the encoder class for the PostgreSQL boolean type.
 *
 * It accepts true and false. Other values will raise an exception.
 *
 */
static int
pg_bin_enc_boolean(t_pg_coder *conv, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	char mybool;
    if (value == Qtrue) {
      mybool = 1;
    } else if (value == Qfalse) {
      mybool = 0;
    } else {
      rb_raise( rb_eTypeError, "wrong data for binary boolean converter" );
	}
	if(out) *out = mybool;
	return 1;
}

/*
 * Document-class: PG::BinaryEncoder::Int2 < PG::SimpleEncoder
 *
 * This is the encoder class for the PostgreSQL +int2+ (alias +smallint+) type.
 *
 * Non-Number values are expected to have method +to_i+ defined.
 *
 */
static int
pg_bin_enc_int2(t_pg_coder *conv, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	if(out){
		write_nbo16(NUM2INT(*intermediate), out);
	}else{
		*intermediate = pg_obj_to_i(value);
	}
	return 2;
}

/*
 * Document-class: PG::BinaryEncoder::Int4 < PG::SimpleEncoder
 *
 * This is the encoder class for the PostgreSQL +int4+ (alias +integer+) type.
 *
 * Non-Number values are expected to have method +to_i+ defined.
 *
 */
static int
pg_bin_enc_int4(t_pg_coder *conv, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	if(out){
		write_nbo32(NUM2LONG(*intermediate), out);
	}else{
		*intermediate = pg_obj_to_i(value);
	}
	return 4;
}

/*
 * Document-class: PG::BinaryEncoder::Int8 < PG::SimpleEncoder
 *
 * This is the encoder class for the PostgreSQL +int8+ (alias +bigint+) type.
 *
 * Non-Number values are expected to have method +to_i+ defined.
 *
 */
static int
pg_bin_enc_int8(t_pg_coder *conv, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	if(out){
		write_nbo64(NUM2LL(*intermediate), out);
	}else{
		*intermediate = pg_obj_to_i(value);
	}
	return 8;
}

/*
 * Document-class: PG::BinaryEncoder::Float4 < PG::SimpleEncoder
 *
 * This is the binary encoder class for the PostgreSQL +float4+ type.
 *
 */
static int
pg_bin_enc_float4(t_pg_coder *conv, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	union {
		float f;
		int32_t i;
	} swap4;

	if(out){
		swap4.f = NUM2DBL(*intermediate);
		write_nbo32(swap4.i, out);
	}else{
		*intermediate = value;
	}
	return 4;
}

/*
 * Document-class: PG::BinaryEncoder::Float8 < PG::SimpleEncoder
 *
 * This is the binary encoder class for the PostgreSQL +float8+ type.
 *
 */
static int
pg_bin_enc_float8(t_pg_coder *conv, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	union {
		double f;
		int64_t i;
	} swap8;

	if(out){
		swap8.f = NUM2DBL(*intermediate);
		write_nbo64(swap8.i, out);
	}else{
		*intermediate = value;
	}
	return 8;
}

#define PG_INT32_MIN    (-0x7FFFFFFF-1)
#define PG_INT32_MAX    (0x7FFFFFFF)
#define PG_INT64_MIN	(-0x7FFFFFFFFFFFFFFFL - 1)
#define PG_INT64_MAX	0x7FFFFFFFFFFFFFFFL

/*
 * Document-class: PG::BinaryEncoder::Timestamp < PG::SimpleEncoder
 *
 * This is a encoder class for conversion of Ruby Time objects to PostgreSQL binary timestamps.
 *
 * The following flags can be used to specify timezone interpretation:
 * * +PG::Coder::TIMESTAMP_DB_UTC+ : Send timestamp as UTC time (default)
 * * +PG::Coder::TIMESTAMP_DB_LOCAL+ : Send timestamp as local time (slower)
 *
 * Example:
 *   enco = PG::BinaryEncoder::Timestamp.new(flags: PG::Coder::TIMESTAMP_DB_UTC)
 *   enco.encode(Time.utc(2000, 1, 1))  # => "\x00\x00\x00\x00\x00\x00\x00\x00"
 *
 * String values are expected to contain a binary data with a length of 8 byte.
 *
 */
static int
pg_bin_enc_timestamp(t_pg_coder *this, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	if(out){
		int64_t timestamp;
		struct timespec ts;

		/* second call -> write data to *out */
		switch(TYPE(*intermediate)){
			case T_STRING:
				return pg_coder_enc_to_s(this, value, out, intermediate, enc_idx);
			case T_TRUE:
				write_nbo64(PG_INT64_MAX, out);
				return 8;
			case T_FALSE:
				write_nbo64(PG_INT64_MIN, out);
				return 8;
		}

		ts = rb_time_timespec(*intermediate);
		/* PostgreSQL's timestamp is based on year 2000 and Ruby's time is based on 1970.
			* Adjust the 30 years difference. */
		timestamp = ((int64_t)ts.tv_sec - 10957L * 24L * 3600L) * 1000000 + ((int64_t)ts.tv_nsec / 1000);

		if( this->flags & PG_CODER_TIMESTAMP_DB_LOCAL ) {
			/* send as local time */
			timestamp += NUM2LL(rb_funcall(*intermediate, rb_intern("utc_offset"), 0)) * 1000000;
		}

		write_nbo64(timestamp, out);
	}else{
		/* first call -> determine the required length */
		if(TYPE(value) == T_STRING){
			char *pstr = RSTRING_PTR(value);
			if(RSTRING_LEN(value) >= 1){
				switch(pstr[0]) {
					case 'I':
					case 'i':
						*intermediate = Qtrue;
						return 8;
					case '-':
						if (RSTRING_LEN(value) >= 2 && (pstr[1] == 'I' || pstr[1] == 'i')) {
							*intermediate = Qfalse;
							return 8;
						}
				}
			}

			return pg_coder_enc_to_s(this, value, out, intermediate, enc_idx);
		}

		if( this->flags & PG_CODER_TIMESTAMP_DB_LOCAL ) {
			/* make a local time, so that utc_offset is set */
			value = rb_funcall(value, rb_intern("getlocal"), 0);
		}
		*intermediate = value;
	}
	return 8;
}

#define POSTGRES_EPOCH_JDATE   2451545 /* == date2j(2000, 1, 1) */
int
date2j(int year, int month, int day)
{
	int			julian;
	int			century;

	if (month > 2)
	{
		month += 1;
		year += 4800;
	}
	else
	{
		month += 13;
		year += 4799;
	}

	century = year / 100;
	julian = year * 365 - 32167;
	julian += year / 4 - century + century / 4;
	julian += 7834 * month / 256 + day;

	return julian;
}								/* date2j() */

/*
 * Document-class: PG::BinaryEncoder::Date < PG::SimpleEncoder
 *
 * This is a encoder class for conversion of Ruby Date objects to PostgreSQL binary date.
 *
 * String values are expected to contain a binary data with a length of 4 byte.
 *
 */
static int
pg_bin_enc_date(t_pg_coder *this, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	if(out){
		/* second call -> write data to *out */
		switch(TYPE(*intermediate)){
			case T_STRING:
				return pg_coder_enc_to_s(this, value, out, intermediate, enc_idx);
			case T_TRUE:
				write_nbo32(PG_INT32_MAX, out);
				return 4;
			case T_FALSE:
				write_nbo32(PG_INT32_MIN, out);
				return 4;
		} {
			VALUE year = rb_funcall(value, s_id_year, 0);
			VALUE month = rb_funcall(value, s_id_month, 0);
			VALUE day = rb_funcall(value, s_id_day, 0);
			int jday = date2j(NUM2INT(year), NUM2INT(month), NUM2INT(day)) - POSTGRES_EPOCH_JDATE;
			write_nbo32(jday, out);
		}
	}else{
		/* first call -> determine the required length */
		if(TYPE(value) == T_STRING){
			char *pstr = RSTRING_PTR(value);
			if(RSTRING_LEN(value) >= 1){
				switch(pstr[0]) {
					case 'I':
					case 'i':
						*intermediate = Qtrue;
						return 4;
					case '-':
						if (RSTRING_LEN(value) >= 2 && (pstr[1] == 'I' || pstr[1] == 'i')) {
							*intermediate = Qfalse;
							return 4;
						}
				}
			}

			return pg_coder_enc_to_s(this, value, out, intermediate, enc_idx);
		}

		*intermediate = value;
	}
	return 4;
}

/*
 * Maximum number of array subscripts (arbitrary limit)
 */
#define MAXDIM 6

/*
 * Document-class: PG::BinaryEncoder::Array < PG::CompositeEncoder
 *
 * This is the encoder class for PostgreSQL array types in binary format.
 *
 * All values are encoded according to the #elements_type
 * accessor. Sub-arrays are encoded recursively.
 *
 * This encoder expects an Array of values or sub-arrays as input.
 * Other values are passed through as byte string without interpretation.
 *
 * It is possible to enforce a number of dimensions to be encoded by #dimensions= .
 * Deeper nested arrays are then passed to the elements encoder and less nested arrays raise an ArgumentError.
 *
 * The accessors needs_quotation and delimiter are ignored for binary encoding.
 *
 */
static int
pg_bin_enc_array(t_pg_coder *conv, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	if (TYPE(value) == T_ARRAY) {
		t_pg_composite_coder *this = (t_pg_composite_coder *)conv;
		t_pg_coder_enc_func enc_func = pg_coder_enc_func(this->elem);
		int dim_sizes[MAXDIM];
		int ndim = 1;
		int nitems = 1;
		VALUE el1 = value;

		if (RARRAY_LEN(value) == 0) {
			nitems = 0;
			ndim = 0;
			dim_sizes[0] = 0;
		} else {
			/* Determine number of dimensions, sizes of dimensions and number of items */
			while(1) {
				VALUE el2;

				dim_sizes[ndim-1] = RARRAY_LENINT(el1);
				nitems *= dim_sizes[ndim-1];
				el2 = rb_ary_entry(el1, 0);
				if ( (this->dimensions < 0 || ndim < this->dimensions) &&
						TYPE(el2) == T_ARRAY) {
					ndim++;
					if (ndim > MAXDIM)
						rb_raise( rb_eArgError, "unsupported number of array dimensions: >%d", ndim );
				} else {
					break;
				}
				el1 = el2;
			}
		}
		if( this->dimensions >= 0 && (ndim==0 ? 1 : ndim) != this->dimensions ){
			rb_raise(rb_eArgError, "less array dimensions to encode (%d) than expected (%d)", ndim, this->dimensions);
		}

		if(out){
			/* Second encoder pass -> write data to `out` */
			int dimpos[MAXDIM];
			VALUE arrays[MAXDIM];
			int dim = 0;
			int item_idx = 0;
			int i;
			char *orig_out = out;
			Oid elem_oid = this->elem ? this->elem->oid : 0;

			write_nbo32(ndim, out); out += 4;
			write_nbo32(1 /* flags */, out); out += 4;
			write_nbo32(elem_oid, out); out += 4;
			for (i = 0; i < ndim; i++) {
				dimpos[i] = 0;
				write_nbo32(dim_sizes[i], out); out += 4;
				write_nbo32(1 /* offset */, out); out += 4;
			}
			arrays[0] = value;

			while(1) {
				/* traverse tree down */
				while (dim < ndim - 1) {
					arrays[dim + 1] = rb_ary_entry(arrays[dim], dimpos[dim]);
					dim++;
				}

				for (i = 0; i < dim_sizes[dim]; i++) {
					VALUE item = rb_ary_entry(arrays[dim], i);

					if (NIL_P(item)) {
						write_nbo32(-1, out); out += 4;
					} else {
						/* Encoded string is returned in subint */
						int strlen;
						VALUE is_one_pass = rb_ary_entry(*intermediate, item_idx++);
						VALUE subint = rb_ary_entry(*intermediate, item_idx++);

						if (is_one_pass == Qtrue) {
							strlen = RSTRING_LENINT(subint);
							memcpy( out + 4, RSTRING_PTR(subint), strlen);
						} else {
							strlen = enc_func(this->elem, item, out + 4, &subint, enc_idx);
						}
						write_nbo32(strlen, out);
						out += 4 /* length */ + strlen;
					}
				}

				/* traverse tree up and go to next sibling array */
				do {
					if (dim > 0) {
						dimpos[dim] = 0;
						dim--;
						dimpos[dim]++;
					} else {
						goto finished2;
					}
				} while (dimpos[dim] >= dim_sizes[dim]);
			}
			finished2:
			return (int)(out - orig_out);

		} else {
			/* First encoder pass -> determine required buffer space for `out` */

			int dimpos[MAXDIM];
			VALUE arrays[MAXDIM];
			int dim = 0;
			int item_idx = 0;
			int i;
			int size_sum = 0;

			*intermediate = rb_ary_new2(nitems);

			for (i = 0; i < MAXDIM; i++) {
				dimpos[i] = 0;
			}
			arrays[0] = value;

			while(1) {

				/* traverse tree down */
				while (dim < ndim - 1) {
					VALUE array = rb_ary_entry(arrays[dim], dimpos[dim]);
					if (TYPE(array) != T_ARRAY) {
						rb_raise( rb_eArgError, "expected Array instead of %+"PRIsVALUE" in dimension %d", array, dim + 1 );
					}
					if (dim_sizes[dim + 1] != RARRAY_LEN(array)) {
						rb_raise( rb_eArgError, "varying number of array elements (%d and %d) in dimension %d", dim_sizes[dim + 1], RARRAY_LENINT(array), dim + 1 );
					}
					arrays[dim + 1] = array;
					dim++;
				}

				for (i = 0; i < dim_sizes[dim]; i++) {
					VALUE item = rb_ary_entry(arrays[dim], i);

					if (NIL_P(item)) {
						size_sum += 4 /* length bytes = -1 */;
					} else {
						VALUE subint;
						int strlen = enc_func(this->elem, item, NULL, &subint, enc_idx);

						/* Gather all intermediate values of elements into an array, which is returned as intermediate for the array encoder */
						if( strlen == -1 ){
							/* Encoded string is returned in subint */
							rb_ary_store(*intermediate, item_idx++, Qtrue);
							rb_ary_store(*intermediate, item_idx++, subint);

							strlen = RSTRING_LENINT(subint);
						} else {
							/* Two passes necessary */
							rb_ary_store(*intermediate, item_idx++, Qfalse);
							rb_ary_store(*intermediate, item_idx++, subint);
						}
						size_sum += 4 /* length bytes */ + strlen;
					}
				}

				/* traverse tree up and go to next sibling array */
				do {
					if (dim > 0) {
						dimpos[dim] = 0;
						dim--;
						dimpos[dim]++;
					} else {
						goto finished1;
					}
				} while (dimpos[dim] >= dim_sizes[dim]);
			}
			finished1:;

			return 4 /* ndim */ + 4 /* flags */ + 4 /* oid */ +
				ndim * (4 /* dim size */ + 4 /* dim offset */) +
				size_sum;
		}
	} else {
		return pg_coder_enc_to_s( conv, value, out, intermediate, enc_idx );
	}
}

/*
 * Document-class: PG::BinaryEncoder::FromBase64 < PG::CompositeEncoder
 *
 * This is an encoder class for conversion of base64 encoded data
 * to it's binary representation.
 *
 */
static int
pg_bin_enc_from_base64(t_pg_coder *conv, VALUE value, char *out, VALUE *intermediate, int enc_idx)
{
	int strlen;
	VALUE subint;
	t_pg_composite_coder *this = (t_pg_composite_coder *)conv;
	t_pg_coder_enc_func enc_func = pg_coder_enc_func(this->elem);

	if(out){
		/* Second encoder pass, if required */
		strlen = enc_func(this->elem, value, out, intermediate, enc_idx);
		strlen = rbpg_base64_decode( out, out, strlen );

		return strlen;
	} else {
		/* First encoder pass */
		strlen = enc_func(this->elem, value, NULL, &subint, enc_idx);

		if( strlen == -1 ){
			/* Encoded string is returned in subint */
			VALUE out_str;

			strlen = RSTRING_LENINT(subint);
			out_str = rb_str_new(NULL, BASE64_DECODED_SIZE(strlen));

			strlen = rbpg_base64_decode( RSTRING_PTR(out_str), RSTRING_PTR(subint), strlen);
			rb_str_set_len( out_str, strlen );
			*intermediate = out_str;

			return -1;
		} else {
			*intermediate = subint;

			return BASE64_DECODED_SIZE(strlen);
		}
	}
}

void
init_pg_binary_encoder(void)
{
	s_id_year = rb_intern("year");
	s_id_month = rb_intern("month");
	s_id_day = rb_intern("day");

	/* This module encapsulates all encoder classes with binary output format */
	rb_mPG_BinaryEncoder = rb_define_module_under( rb_mPG, "BinaryEncoder" );

	/* Make RDoc aware of the encoder classes... */
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Boolean", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Boolean", pg_bin_enc_boolean, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Int2", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Int2", pg_bin_enc_int2, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Int4", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Int4", pg_bin_enc_int4, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Int8", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Int8", pg_bin_enc_int8, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Float4", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Float4", pg_bin_enc_float4, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Float8", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Float8", pg_bin_enc_float8, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "String", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "String", pg_coder_enc_to_s, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Bytea", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Bytea", pg_coder_enc_to_s, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Timestamp", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Timestamp", pg_bin_enc_timestamp, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Date", rb_cPG_SimpleEncoder ); */
	pg_define_coder( "Date", pg_bin_enc_date, rb_cPG_SimpleEncoder, rb_mPG_BinaryEncoder );

	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "Array", rb_cPG_CompositeEncoder ); */
	pg_define_coder( "Array", pg_bin_enc_array, rb_cPG_CompositeEncoder, rb_mPG_BinaryEncoder );
	/* dummy = rb_define_class_under( rb_mPG_BinaryEncoder, "FromBase64", rb_cPG_CompositeEncoder ); */
	pg_define_coder( "FromBase64", pg_bin_enc_from_base64, rb_cPG_CompositeEncoder, rb_mPG_BinaryEncoder );
}