/* See LICENSE file for copyright and license details. */
#define LIBBLIND_NO_NAMESPACE
#include "libblind.h"

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>


extern int writeall(int fd, const void *buf, size_t n);



#if defined(POSIX_FADV_SEQUENTIAL)
# define fadvise_sequential(...)  posix_fadvise(__VA_ARGS__, POSIX_FADV_SEQUENTIAL)
#else
# define fadvise_sequential(...)
#endif


#define MIN(A, B) ((A) < (B) ? (A) : (B))
#define ELEMSOF(A) (sizeof(A) / sizeof(*(A)))


#define X(NUM, NAM, STR) ,STR
static const char *error_names[] = {
	"Success", NULL
	LIBBLIND_LIST_ERRORS(X)
};
#undef X


const char *
libblind_strerror(int errnum)
{
	const char *ret;
	errnum = -errnum;
	if (errnum < 0 || errnum >= ELEMSOF(error_names))
		return "Unknown libblind error";
	ret = error_names[errnum];
	return ret ? ret : strerror(errno);
}


void
libblind_perror(const char *prefix, int errnum)
{
	fprintf(stderr, "%s%s%s\n",
	        prefix ? prefix : "",
	        prefix ? ": " : "",
	        libblind_strerror(errnum));
}


const char *
libblind_get_pixfmt(const char *specified, const char *current)
{
	enum colour_space space = CIEXYZ;
	enum alpha alpha = UNPREMULTIPLIED;
	enum encoding encoding = UINT16;
	int level = -1;
	size_t n = strlen(specified);

	if ((n >= 2 && !strcmp(specified - 2, " f")) ||
	    !strcmp(specified, "raw0") || !strcmp(specified, "raw1") ||
	    !strcmp(specified, "raw2") || !strcmp(specified, "raw2a"))
		return specified;

	if      (!strcmp(current, "xyza"))    space = CIEXYZ, encoding = DOUBLE;
	else if (!strcmp(current, "xyza f"))  space = CIEXYZ, encoding = FLOAT;
	else if (!strcmp(current, "raw0"))    level = 0;
	else if (!strcmp(current, "raw1"))    level = 1;
	else if (!strcmp(current, "raw2"))    level = 2, alpha = NO_ALPHA;
	else if (!strcmp(current, "raw2a"))   level = 2;
	else if (!strcmp(current, "raw3"))    level = 3, encoding = DOUBLE, alpha = NO_ALPHA;
	else if (!strcmp(current, "raw3a"))   level = 3, encoding = DOUBLE;
	else if (!strcmp(current, "raw3 f"))  level = 3, encoding = FLOAT, alpha = NO_ALPHA;
	else if (!strcmp(current, "raw3a f")) level = 3, encoding = FLOAT;
	else if (!strcmp(current, "raw4"))    level = 4, encoding = DOUBLE, alpha = NO_ALPHA;
	else if (!strcmp(current, "raw4a"))   level = 4, encoding = DOUBLE;
	else if (!strcmp(current, "raw4 f"))  level = 4, encoding = FLOAT, alpha = NO_ALPHA;
	else if (!strcmp(current, "raw4a f")) level = 4, encoding = FLOAT;
	else if (!strcmp(current, "raw5"))    level = 5, encoding = DOUBLE, alpha = NO_ALPHA;
	else if (!strcmp(current, "raw5a"))   level = 5, encoding = DOUBLE;
	else if (!strcmp(current, "raw5 f"))  level = 5, encoding = FLOAT, alpha = NO_ALPHA;
	else if (!strcmp(current, "raw5a f")) level = 5, encoding = FLOAT;
	else
		return specified;

	if      (!strcmp(specified, "f"))        encoding = FLOAT;
	else if (!strcmp(specified, "!f"))       encoding = DOUBLE;
	else if (!strcmp(specified, "xyza"))     level = -1, alpha = UNPREMULTIPLIED, space = CIEXYZ;
	else if (!strcmp(specified, "raw3"))     level = 3, alpha = NO_ALPHA;
	else if (!strcmp(specified, "raw3a"))    level = 3, alpha = UNPREMULTIPLIED;
	else if (!strcmp(specified, "raw4"))     level = 4, alpha = NO_ALPHA;
	else if (!strcmp(specified, "raw4a"))    level = 4, alpha = UNPREMULTIPLIED;
	else if (!strcmp(specified, "raw5"))     level = 5, alpha = NO_ALPHA;
	else if (!strcmp(specified, "raw5a"))    level = 5, alpha = UNPREMULTIPLIED;
	else if (!strcmp(specified, "xyza !f"))  return "xyza";
	else if (!strcmp(specified, "raw3 !f"))  return "raw3";
	else if (!strcmp(specified, "raw3a !f")) return "raw3a";
	else if (!strcmp(specified, "raw4 !f"))  return "raw4";
	else if (!strcmp(specified, "raw4a !f")) return "raw4a";
	else if (!strcmp(specified, "raw5 !f"))  return "raw5";
	else if (!strcmp(specified, "raw5a !f")) return "raw5a";
	else
		return specified;

	if      (level == 0 && encoding == UINT16) return "raw0";
	else if (level == 1 && encoding == UINT16) return "raw1";
	else if (level == 2 && encoding == UINT16) return alpha ? "raw2a"   : "raw2";
	else if (level == 3 && encoding == DOUBLE) return alpha ? "raw3a"   : "raw3";
	else if (level == 3 && encoding == FLOAT)  return alpha ? "raw3a f" : "raw3 f";
	else if (level == 4 && encoding == DOUBLE) return alpha ? "raw4a"   : "raw4";
	else if (level == 4 && encoding == FLOAT)  return alpha ? "raw4a f" : "raw4 f";
	else if (level == 5 && encoding == DOUBLE) return alpha ? "raw5a"   : "raw5";
	else if (level == 5 && encoding == FLOAT)  return alpha ? "raw5a f" : "raw5 f";
	else if (level < 0 && space == CIEXYZ && alpha == UNPREMULTIPLIED)
		return encoding == FLOAT ? "xyza f" : encoding == DOUBLE ? "xyza" : specified;
	else
		return specified;
}


int
libblind_set_pixfmt(struct libblind_stream *stream, const char *pixfmt)
{
#define TEST_ENCODING_AGNOSTIC(FMT) (!strcmp(stream->pixfmt, FMT) || !strcmp(stream->pixfmt, FMT" f"))

	if (pixfmt) {
		pixfmt = get_pixfmt(pixfmt, stream->pixfmt[0] ? stream->pixfmt : "xyza");
		if (strlen(pixfmt) >= sizeof(stream->pixfmt))
			return LIBBLIND_EPIXFMTNOSUPPORT;
		strcpy(stream->pixfmt, pixfmt);
	}

	stream->n_chan = 4;
	stream->alpha = UNPREMULTIPLIED;
	stream->encoding = DOUBLE;
	stream->endian = HOST;
	stream->alpha_chan = 3;
	stream->luma_chan = -1;

	if (!strcmp(stream->pixfmt, "xyza")) {
		stream->space = CIEXYZ;
	} else if (!strcmp(stream->pixfmt, "xyza f")) {
		stream->space = CIEXYZ;
		stream->encoding = FLOAT;
	} else if (!strcmp(stream->pixfmt, "raw0")) {
		stream->space = YUV_NONLINEAR;
		stream->encoding = UINT16;
		stream->endian = LITTLE;
		stream->alpha_chan = 0;
		stream->luma_chan = 1;
	} else if (!strcmp(stream->pixfmt, "raw1")) {
		stream->space = YUV_NONLINEAR;
		stream->encoding = UINT16;
		stream->endian = LITTLE;
	} else if (!strcmp(stream->pixfmt, "raw2a") || !strcmp(stream->pixfmt, "raw2")) {
		stream->space = YUV_NONLINEAR;
		stream->alpha = stream->pixfmt[4] == 'a' ? UNPREMULTIPLIED : NO_ALPHA;
		stream->encoding = UINT16;
	} else if (TEST_ENCODING_AGNOSTIC("raw3") || TEST_ENCODING_AGNOSTIC("raw3a")) {
		stream->space = YUV_NONLINEAR;
		stream->alpha = stream->pixfmt[4] == 'a' ? UNPREMULTIPLIED : NO_ALPHA;
		stream->encoding = strlen(stream->pixfmt) > 5 ? FLOAT : DOUBLE;
	} else if (TEST_ENCODING_AGNOSTIC("raw4") || TEST_ENCODING_AGNOSTIC("raw4a")) {
		stream->space = SRGB_NONLINEAR;
		stream->alpha = stream->pixfmt[4] == 'a' ? UNPREMULTIPLIED : NO_ALPHA;
		stream->encoding = strlen(stream->pixfmt) > 5 ? FLOAT : DOUBLE;
	} else if (TEST_ENCODING_AGNOSTIC("raw5") || TEST_ENCODING_AGNOSTIC("raw5a")) {
		stream->space = SRGB;
		stream->alpha = stream->pixfmt[4] == 'a' ? UNPREMULTIPLIED : NO_ALPHA;
		stream->encoding = strlen(stream->pixfmt) > 5 ? FLOAT : DOUBLE;
	} else {
		return LIBBLIND_EPIXFMTNOSUPPORT;
	}

	if (stream->alpha == NO_ALPHA) {
		stream->n_chan -= 1;
		stream->alpha_chan = -1;
	}

	if (stream->luma_chan == -1) {
		if (stream->space == CIEXYZ)
			stream->luma_chan = 1;
		else if (stream->space == YUV_NONLINEAR)
			stream->luma_chan = 0;
	}

	switch (stream->encoding) {
	case FLOAT:
		stream->chan_size = sizeof(float);
		break;
	case DOUBLE:
		stream->chan_size = sizeof(double);
		break;
	case LONG_DOUBLE:
		stream->chan_size = sizeof(long double);
		break;
	case UINT8:
		stream->chan_size = sizeof(uint8_t);
		break;
	case UINT16:
		stream->chan_size = sizeof(uint16_t);
		break;
	case UINT32:
		stream->chan_size = sizeof(uint32_t);
		break;
	case UINT64:
		stream->chan_size = sizeof(uint64_t);
		break;
	default:
		return LIBBLIND_ECORRUPTSTATE;
	}

	stream->pixel_size = stream->n_chan * stream->chan_size;
	stream->row_size   = stream->pixel_size * stream->width;
	stream->col_size   = stream->pixel_size * stream->height;
	stream->frame_size = stream->pixel_size * stream->height * stream->width;
	return 0;

#undef TEST_ENCODING_AGNOSTIC
}


ssize_t
libblind_read_stream(struct libblind_stream *stream, size_t n)
{
	ssize_t r;
	n = MIN(n, sizeof(stream->buf) - stream->ptr);
	r = read(stream->fd, &stream->buf[stream->ptr], n);
	if (r > 0)
		stream->ptr += (size_t)r;
	return r;
	/* LIBBLIND_ESYSTEM == -1 and read(3p) explicitly specifies -1 on error */
}


static inline int
get_dimension(size_t *out, const char *s, int dimerr)
{
	char *end;
	int saved_errno = errno;
	errno = 0;
	*out = strtoul(s, &end, 10);
	if (errno == ERANGE && *s != '-')
		return dimerr;
	errno = saved_errno;
	return LIBBLIND_EBADFORMAT;
}


int
libblind_init_stream(struct libblind_stream *stream)
{
	char *p = NULL, *w, *h, *f;
	size_t n;
	ssize_t r;
	int err;

	if (stream->fd >= 0) {
		fadvise_sequential(stream->fd, 0, 0);
		for (stream->ptr = 0; !p; p = memchr(stream->buf, '\n', stream->ptr))
			if ((r = libblind_read_stream(stream, SIZE_MAX)) <= 0)
				return r ? r : LIBBLIND_EBADFORMAT;
	} else {
		p = memchr(stream->buf, '\n', stream->ptr);
	}

	*p = '\0';
	if (!(w = strchr(stream->buf, ' ')) ||
	    !(h = strchr(&w[1], ' ')) ||
	    !(f = strchr(&h[1], ' ')))
		return LIBBLIND_EBADFORMAT;
	*w++ = *h++ = *f++ = '\0';

	if (strlen(f) >= sizeof(stream->pixfmt))
		return LIBBLIND_EBADFORMAT;
	strcpy(stream->pixfmt, f);
	if ((err = get_dimension(&stream->frames, stream->buf, LIBBLIND_EVIDTOOLONG)) ||
	    (err = get_dimension(&stream->width,  w,           LIBBLIND_EVIDTOOWIDE)) ||
	    (err = get_dimension(&stream->height, h,           LIBBLIND_EVIDTOOTALL)))
		return err;

	if (!stream->width)
		return LIBBLIND_EZEROWIDTH;
	if (!stream->height)
		return LIBBLIND_EZEROHEIGHT;

	n = (size_t)(p - stream->buf) + 1;
	memmove(stream->buf, &stream->buf[n], stream->ptr -= n);
	while (stream->ptr < 5)
		if ((r = libblind_read_stream(stream, SIZE_MAX)) <= 0)
			return r ? r : LIBBLIND_EBADFORMAT;
	if (stream->buf[0] != '\0' ||
	    stream->buf[1] != 'u' || stream->buf[2] != 'i' ||
	    stream->buf[3] != 'v' || stream->buf[4] != 'f')
		return LIBBLIND_EBADFORMAT;
	memmove(stream->buf, &stream->buf[5], stream->ptr -= 5);
	stream->headlen = n + 5;

	if ((err = libblind_set_pixfmt(stream, NULL)))
		return err;

	stream->xptr = 0;

	return 0;
}


int
libblind_check_dimensions(const struct stream *stream, enum dimension dimensions)
{
	size_t n;

	if (!stream->pixel_size)
		return LIBBLIND_ECORRUPTSTATE;
	n = SIZE_MAX / stream->pixel_size;

	if ((dimensions & WIDTH) && stream->width > n)
		return LIBBLIND_EFRMTOOWIDE;
	if ((dimensions & HEIGHT) && stream->height > n)
		return LIBBLIND_EFRMTOOTALL;
	if (!stream->width || !stream->height)
		return 0;

	if ((dimensions & (WIDTH | HEIGHT)) == (WIDTH | HEIGHT))
		if (stream->width > n / stream->height)
			return LIBBLIND_EFRMTOOLARGE;

	if (!(dimensions & LENGTH))
		return 0;
	if (dimensions & WIDTH)
		n /= stream->width;
	if (dimensions & HEIGHT)
		n /= stream->height;

	if (stream->frames > n)
		return LIBBLIND_EVIDTOOLARGE;

	return 0;
}


int
libblind_read_segment(struct stream *stream, void *buf, size_t n)
{
	char *buffer = buf;
	ssize_t r;
	size_t m;

	if (stream->ptr) {
		m = MIN(stream->ptr, n);
		memcpy(&buffer[stream->xptr], stream->buf, m);
		memmove(stream->buf, &stream->buf[m], stream->ptr -= m);
		stream->xptr += m;
	}

	for (; stream->xptr < n; stream->xptr += (size_t)r) {
		r = read(stream->fd, &buffer[stream->xptr], n - stream->xptr);
		if (r < 0)
			return LIBBLIND_ESYSTEM;
		if (!r) {
			if (!stream->xptr)
				break;
			return LIBBLIND_EINCOMPLETE;
		}
	}

	if (!stream->xptr)
		return 0;
	stream->xptr -= n;
	return 1;
}


ssize_t
libblind_send_frames(struct libblind_stream *stream, int outfd, size_t frames, int *outfailed)
{
	size_t h, w, p, n, ret;
	ssize_t r;

	for (ret = 0; ret < frames; ret++) {
		for (p = stream->pixel_size; p; p--) {
			for (h = stream->height; h; h--) {
				for (w = stream->width; w; w -= n) {
					if (!stream->ptr && (r = libblind_read_stream(stream, w)) <= 0) {
						if (outfailed)
							*outfailed = 0;
						if (!r)
							goto done;
						return r;
					}
					n = MIN(stream->ptr, p);
					if (outfd >= 0 && writeall(outfd, stream->buf, n)) {
						if (outfailed)
							*outfailed = 1;
						return LIBBLIND_ESYSTEM;
					}
					memmove(stream->buf, &stream->buf[n], stream->ptr -= n);
				}
			}
		}
	}

	return ret;
done:
	if (p != stream->pixel_size)
		return (ssize_t)LIBBLIND_EINCOMPLETEFRAME;
	/* Note that due to order of the nested for-loops, we don't
	 * know which unit is incomplete: pixel, row, or frame. */
	return ret;
}


ssize_t
libblind_send_rows(struct libblind_stream *stream, int outfd, size_t rows, int *outfailed)
{
	size_t w, p, n, ret;
	ssize_t r;

	for (ret = 0; ret < rows; ret++) {
		for (p = stream->pixel_size; p; p--) {
			for (w = stream->width; w; w -= n) {
				if (!stream->ptr && (r = libblind_read_stream(stream, w)) <= 0) {
					if (outfailed)
						*outfailed = 0;
					if (!r)
						goto done;
					return r;
				}
				n = MIN(stream->ptr, p);
				if (outfd >= 0 && writeall(outfd, stream->buf, n)) {
					if (outfailed)
						*outfailed = 1;
					return LIBBLIND_ESYSTEM;
				}
				memmove(stream->buf, &stream->buf[n], stream->ptr -= n);
			}
		}
	}

	return ret;
done:
	if (p != stream->pixel_size)
		return (ssize_t)LIBBLIND_EINCOMPLETEROW;
	/* Note that due to order of the nested for-loops, we don't
	 * know whether a pixel is incomplete or just a row. */
	return ret;
}


ssize_t
libblind_send_pixels(struct libblind_stream *stream, int outfd, size_t pixels, int *outfailed)
{
	size_t p, n, ret;
	ssize_t r;

	for (ret = 0; ret < pixels; ret++) {
		for (p = stream->pixel_size; p; p -= n) {
			if (!stream->ptr && (r = libblind_read_stream(stream, p)) <= 0) {
				if (outfailed)
					*outfailed = 0;
				if (!r)
					goto done;
				return r;
			}
			n = MIN(stream->ptr, p);
			if (outfd >= 0 && writeall(outfd, stream->buf, n)) {
				if (outfailed)
					*outfailed = 1;
				return LIBBLIND_ESYSTEM;
			}
			memmove(stream->buf, &stream->buf[n], stream->ptr -= n);
		}
	}

	return ret;
done:
	if (p != stream->pixel_size)
		return (ssize_t)LIBBLIND_EINCOMPLETEPIX;
	return ret;
}


int
libblind_send_stream(struct libblind_stream *stream, int outfd, int *outfailed)
{
	ssize_t r;
	do {
		if (writeall(outfd, stream->buf, stream->ptr)) {
			if (outfailed)
				*outfailed = 1;
			return LIBBLIND_ESYSTEM;
		}
		stream->ptr = 0;
	} while ((r = libblind_read_stream(stream, SIZE_MAX)) > 0);
	if (outfailed)
		*outfailed = 0;
	return -(r < 0);
}