/*
 * small libc functions for the PSXSDK
 *
 * In this file, C functions either not implemented by the BIOS
 * or very broken in the BIOS are implemented independently
 *
 * Some functions, such as printf, have both a BIOS implementation
 * and an implementation here. The implementation here is prefixed
 * with libc_ to not make confusion.
 */

#include <psx.h>
#include <stdio.h>
#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <strings.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>

int errno;
int __stdio_direction = STDIO_DIRECTION_BIOS;
static unsigned int __sio_cr_mapped = 0;

#define NUM_OF_FILE_STRUCTS 6

enum {SECTOR_SZ = 2048};

static FILE file_structs[NUM_OF_FILE_STRUCTS]  =
{
		[0] = // stdin
		{
			.fildes = 0,
			.pos = 0,
			.mode = O_RDONLY,
			.dev = FDEV_CONSOLE,
			.size = 0,
			.used = 1,
			.eof = 0,
			.error = 0
		},
		[1] = // stdout
		{
			.fildes = 1,
			.pos = 0,
			.mode = O_WRONLY,
			.dev = FDEV_CONSOLE,
			.size = 0,
			.used = 1,
			.eof = 0,
			.error = 0
		},
		[2] = // stderr
		{
			.fildes = 2,
			.pos = 0,
			.mode = O_WRONLY,
			.dev = FDEV_CONSOLE,
			.size = 0,
			.used = 1,
			.eof = 0,
			.error = 0
		},

		[3 ... NUM_OF_FILE_STRUCTS - 1] =
		{
			.buf = (unsigned char[SECTOR_SZ]){}
		}
};

FILE *const stdin = &file_structs[0];
FILE *const stdout = &file_structs[1];
FILE *const stderr = &file_structs[2];

#define IS_CONS_IN(f)	(f->fildes == 0)
#define IS_CONS_OUT(f)	(f->fildes == 1 || f->fildes == 2)

//unsigned char file_state[NUM_OF_FILE_STRUCTS];

int libc_get_transtbl_fname(const char *tofind, char *outstr, int outl);

unsigned int fmode_to_desmode(const char *fmode)
{
	char rmode[16];
	int x, y;

	y = 0;

	for(x=0;x<15;x++)
	{
		if(fmode[x] == 0)
			break;
		else
		{
			if(fmode[x] != 'b' && fmode[x] != 'f')
				rmode[y++] = fmode[x];
		}
	}

	rmode[y] = 0;

	if(strcmp(rmode, "r") == 0)
	{
		return O_RDONLY;
	}
	else if(strcmp(rmode, "r+") == 0)
	{
		return O_RDWR;
	}
	else if(strcmp(rmode, "w") == 0)
	{
		return O_WRONLY | O_CREAT | O_TRUNC;
	}
	else if(strcmp(rmode, "w+") == 0)
	{
		return O_RDWR | O_CREAT | O_TRUNC;
	}
	else if(strcmp(rmode, "a") == 0)
	{
		dprintf("Append; open for writing. Create file if it doesn't exist.\n");
		return O_WRONLY | O_APPEND;
	}
	else if(strcmp(rmode, "a+") == 0)
	{
		dprintf("Append; open for reading and writing. Create file if it doesn't exist.\n");
		return O_RDWR | O_APPEND | O_CREAT;
	}
	else
	{
		return 0;
	}
}

FILE *fdopen(int fildes, const char *mode)
{
// Adjust for malloc
	int x;

// Find a free file structure
	for(x = 0; x < NUM_OF_FILE_STRUCTS; x++)
	{
		FILE *const f = &file_structs[x];

		if(f->used == 0)
		{
			f->size = 0;
			f->eof = 0;
			f->error = 0;
			f->used = 1;
			f->last_sect = 0;
			f->cache_available = 0;

			if (f->buf)
				memset(f->buf, 0, SECTOR_SZ);

			break;
		}
	}

// If we found no free file structure, return NULL pointer

	if(x == NUM_OF_FILE_STRUCTS)
		return NULL;

	file_structs[x].fildes = fildes;
	file_structs[x].pos = lseek(fildes, 0, SEEK_CUR);
	file_structs[x].mode = fmode_to_desmode(mode);

	return &file_structs[x];
}

static FILE *fopen_internal(const char *path, const char *mode, FILE *f)
{
	int fd;
	char *s = NULL;

	if(strncmp(path, "cdromL:", 7) == 0)
	{
#ifdef PSXSDK_CDROML_ENABLED
		s = malloc(1024);

		if(libc_get_transtbl_fname(path+7, s, 1024) == 0)
			return NULL;

		fd = open(s, fmode_to_desmode(mode));
#else
		return NULL;
#endif
	}
	else
		fd = open(path, fmode_to_desmode(mode));

	if(fd == -1)
	{
		errno = ENOENT;
		if(s!=NULL)free(s);
		return NULL;
	}

	if(f == NULL)
		f = fdopen(fd, mode);
	else
	{
		f->fildes = fd;
		f->pos = lseek(fd, 0, SEEK_CUR);
		f->mode = fmode_to_desmode(mode);
	}

	if(f == NULL)
	{
		if(s!=NULL)free(s);
		return NULL;
	}

	f->dev = FDEV_UNKNOWN;

	if(strncmp(path, "cdrom", 5) == 0 || strncmp(path, "cdromL", 6) == 0)
		f->dev = FDEV_CDROM;
	else if(strncmp(path, "bu", 2) == 0)
		f->dev = FDEV_MEMCARD;

// nocash bios freezes at get_real_file_size(), due
// to problems with firstfile()

	if(s!=NULL)
	{
		f->size = get_real_file_size(s);
		free(s);
	}
	else
		f->size = get_real_file_size(path);

	return f;
}

FILE *fopen(const char *path, const char *mode)
{
	return fopen_internal(path, mode, NULL);
}

int fclose(FILE *stream)
{
	stream->used = 0;
	close(stream->fildes);
	return 0;
}

static size_t cdromread(void *restrict ptr, size_t sz,
						FILE *restrict const f)
{
	const size_t start_sect = f->pos >> __builtin_ctz(SECTOR_SZ);
	const size_t end_pos = f->pos + sz;
	const size_t end_sector = end_pos >> __builtin_ctz(SECTOR_SZ);
	size_t readb = 0;
	int read_complete_sector = 0;

	if (feof(f) || ferror(f))
		return 0;
	else if (f->cache_available)
	{
		const size_t first_sector_sz = f->pos % SECTOR_SZ;

		if (f->last_sect == start_sect && f->last_sect == end_sector)
		{
			/* Use buffered I/O. */
			size_t max;

			if (end_pos >= f->size)
			{
				max = f->size - f->pos;
				f->eof = 1;
			}
			else
			{
				max = sz;
			}

			memcpy(ptr, &f->buf[first_sector_sz], max);
			f->pos += max;
			readb = max;
		}
		else if (f->last_sect == start_sect)
		{
			/* Partial buffered I/O possible. */
			const size_t firstsz = SECTOR_SZ - first_sector_sz;

			memcpy(ptr, &f->buf[first_sector_sz], firstsz);
			ptr = (char *)ptr + firstsz;
			f->pos += firstsz;
			f->cache_available = 0;
			readb += firstsz;
			read_complete_sector = 1;
		}
	}

	const size_t rem = sz - readb;

	if (rem)
	{
		const size_t whole_sectors = rem / SECTOR_SZ;

		if (whole_sectors)
		{
			if (!read_complete_sector)
				lseek(f->fildes, f->pos & ~(SECTOR_SZ - 1), SEEK_SET);

			const size_t s = whole_sectors * SECTOR_SZ;
			const int n = read(f->fildes, &((unsigned char *)ptr)[readb], s);

			if (n >= 0)
			{
				readb += s;
				f->pos += s;
				ptr = (unsigned char *)ptr + s;

				if (f->pos >= f->size)
					f->eof = 1;

				f->cache_available = 1;
			}
		}

		if (f->pos < f->size)
		{
			int n;

			if (!read_complete_sector)
				lseek(f->fildes, f->pos & ~(SECTOR_SZ - 1), SEEK_SET);

			n = read(f->fildes, f->buf, SECTOR_SZ);

			if (n >= 0)
			{
				readb = n > rem ? rem : n;

				memmove(ptr, f->buf, readb);
				ptr = (unsigned char *)ptr + readb;
				f->pos += readb;

				if (f->pos >= f->size)
					f->eof = 1;

				f->cache_available = 1;
			}
		}
	}

	f->last_sect = end_sector;
	return f->pos;
}

/*
 * fread doesn't require reads to be carried in block unit
 * Notice that however seeks on the CD drive will be very slow - so avoid using non block units
 *
 * This is done to make programming and porting easier
 */

size_t fread(void *restrict const ptr, const size_t size, const size_t nmemb,
			 FILE *restrict const f)
{
	if (size && nmemb)
	{
		size_t rsize = size * nmemb;

		switch (f->dev)
		{
			case FDEV_CDROM:
				rsize = cdromread(ptr, rsize, f);
				break;

			case FDEV_CONSOLE:
				/* Fall through. */
			default:
				return 0;
		}

		return rsize / size;
	}

	return 0;
}

int fgetc(FILE *f)
{
	unsigned char c;

	if(f->pos >= f->size)
		return EOF;

	fread(&c, sizeof(char), 1, f);

	return (int)c;
}

int ftell(FILE *f)
{
	return f->pos;
}

int fseek(FILE *f, int offset, int whence)
{
	switch(whence)
	{
		case SEEK_SET:
			f->pos = offset;
		break;
		case SEEK_CUR:
			f->pos+= offset;
		break;
		case SEEK_END:
			f->pos = f->size + offset;
		break;
		default:
			f->pos = whence + offset;
		break;
	}

	return 0;
}

void rewind(FILE *f)
{
	fseek(f, 0, SEEK_SET);
	clearerr(f);
}

int toupper(int c)
{
	if(c >= 'a' && c <= 'z')
		return (c-'a')+'A';

	return c;
}

int tolower(int c)
{
	if(c >= 'A' && c <= 'Z')
		return (c-'A')+'a';

	return c;
}

int libc_get_transtbl_fname(const char *tofind, char *outstr, int outl)
{
	FILE *f;
	int s;
	int x;
	int type = 0;
	int y;
	int l = strlen(tofind);
	int filename_found = 0;
	int exit_loop = 0;
	int otfp = 0;
	int tfp = 0;
	char transtbl[0x4000];
	char orgname[16];
	char newname[256];
	char rootpath[256];

	bzero(transtbl, 0x4000);
	strcpy(rootpath, "cdrom:\\");

	f = fopen("cdrom:\\TRANS.TBL;1", "rb");

	if(f == NULL)
		return 0;

	fseek(f, 0, SEEK_END);
	s = ftell(f);
	fseek(f, 0, SEEK_SET);
	fread(transtbl, 1, s, f);
	fclose(f);

	outstr[0] = 0;

	x = 0;

	exit_loop = 0;
	filename_found = 0;

	for(tfp = 0; tofind[tfp] == '\\' || tofind[tfp] == '/'; tfp++);

	otfp = tfp;

	for(y = otfp; y < l; y++)
	{
		if(tofind[y] == '\0' || tofind[y] == '\\' || tofind[y] == '/')
			break;
	}

	tfp = y;

	while((x < s) && !exit_loop)
	{
		while(transtbl[x] == ' ' || transtbl[x] == '\t' || transtbl[x] == '\n' || transtbl[x] == '\r')
			x++;

		if(transtbl[x] == 'F')
			type = 0;
		else if(transtbl[x] == 'D')
			type = 1;

		x++;

		while(transtbl[x] == ' ' || transtbl[x] == '\t' || transtbl[x] == '\n' || transtbl[x] == '\r')
			x++;

		y = 0;

		while(!(transtbl[x] == ' ' || transtbl[x] == '\t' || transtbl[x] == '\n' || transtbl[x] == '\r'
		|| transtbl[x] == 0))
				orgname[y++] = transtbl[x++];

		orgname[y] = 0;
		//printf("orgname = %s\n", orgname);

		while(transtbl[x] == ' ' || transtbl[x] == '\t' || transtbl[x] == '\n' || transtbl[x] == '\r')
			x++;

		y = 0;

		while(!(transtbl[x] == '\n' || transtbl[x] == '\r' || transtbl[x] == 0))
			newname[y++] = transtbl[x++];

		newname[y] = 0;

		while(transtbl[x] == ' ' || transtbl[x] == '\t' || transtbl[x] == '\n' || transtbl[x] == '\r')
			x++;

		//printf("newname = %s\n", newname);

		if(strncasecmp(&tofind[otfp],  newname, tfp-otfp) == 0)
		{
			if(type == 0)
			{
				dprintf("Filename found: %s -> %s%s\n", tofind, rootpath, orgname);
				filename_found = 1;
				exit_loop = 1;

				strncpy(outstr, rootpath, outl);
				strncat(outstr, orgname, outl-strlen(rootpath));
			}
			else
			{
				//printf("Found directory! %s\n", newname);

				//printf("tfp = %d\n", tfp);

				if(tfp == l || tofind[l-1] == '/'
					|| tofind[l-1] == '\\')
				{
					dprintf("File not found. A directory was specified.\n");
					exit_loop = 1;
					continue;
				}

				//tfp++;
				for(; tofind[tfp] == '\\' || tofind[tfp] == '/'; tfp++);

				otfp = tfp;

				for(y = otfp; y < l; y++)
				{
					if(tofind[y] == '\0' || tofind[y] == '\\' || tofind[y] == '/')
						break;
				}

				tfp = y;

				strcat(rootpath, orgname);
				strcat(rootpath, "\\");

				y = strlen(rootpath);
				strcat(rootpath, "TRANS.TBL;1");

				bzero(transtbl, 0x4000);

				f = fopen(rootpath, "rb");

				if(f == NULL)
				{
					dprintf("Couldn't find %s\n", rootpath);
					exit_loop = 1;
					continue;
				}

				rootpath[y] = 0;

				fseek(f, 0, SEEK_END);
				s = ftell(f);
				fseek(f, 0, SEEK_SET);
				fread(transtbl, 1, s, f);
				fclose(f);

				x = 0;
			}
		}
	}

	return filename_found;
}

int isupper(int c)
{
	return (c >= 'A' && c <= 'Z');
}

int islower(int c)
{
	return (c >= 'a' && c <= 'z');
}

int isdigit(int c)
{
	return (c >= '0' && c <= '9');
}

int isxdigit(int c)
{
	return ((c >= '0' && c <= '9') || (c >= 'A' && c<='F') || (c >= 'a' && c<='f'));
}

int isalpha(int c)
{
	return ((c>='a' && c<='z') || (c>='A' && c<='Z'));
}

int isalnum(int c)
{
	return ((c>='a' && c<='z') || (c>='A' && c<='Z') || (c>='0' && c<='9'));
}

int isspace(int c)
{
	return ((c == ' ') || (c == '\f') || (c == '\n') || (c == '\r') || (c == '\t') || (c == '\v'));
}

int isprint(int c)
{
	return (c >= 0x20) && (c <= 0x7E);
}

int isgraph(int c)
{
	return (c > 0x20) && (c <= 0x7E);
}

int iscntrl(int c)
{
	return (c < 0x20);
}

int isblank(int c)
{
	return ((c == ' ') || (c == '\t'));
}

void redirect_stdio_to_sio(void)
{
	__stdio_direction = STDIO_DIRECTION_SIO;
}

void sio_stdio_mapcr(unsigned int setting)
{
	__sio_cr_mapped = setting;
}

int sio_putchar(int c)
{
	if(c == '\n' && __sio_cr_mapped)
		sio_putchar('\r');

	while(!SIOCheckOutBuffer());

	SIOSendByte(c);

	return c;
}

int sio_puts(const char *str)
{
	while(*str)
		sio_putchar(*(str++));

	sio_putchar('\n');

	return 1;
}

extern int bios_putchar(int c);
extern int bios_puts(const char *str);

int putchar(int c)
{
	switch(__stdio_direction)
	{
		case STDIO_DIRECTION_BIOS:
			return bios_putchar(c);
		break;
		case STDIO_DIRECTION_SIO:
			return sio_putchar(c);
		break;
	}

	return EOF;
}

int puts(const char *str)
{
	switch(__stdio_direction)
	{
		case STDIO_DIRECTION_BIOS:
			return bios_puts(str);
		break;
		case STDIO_DIRECTION_SIO:
			return sio_puts(str);
		break;
	}

	return EOF;
}

size_t fwrite(const void *restrict const ptr, const size_t size, const size_t nmemb,
			  FILE *restrict const f)
{
	if(IS_CONS_OUT(f)) // stdout or stderr
	{
		const char *c = ptr;
		int i;

		for(i = 0; i < size; i++)
			putchar(c[i]);

		return size;
	}

	return 0;
}

int fputs(const char *str, FILE *stream)
{
	if(IS_CONS_OUT(stream))
		return puts(str);

	return EOF;
}

FILE *freopen(const char *path, const char *mode, FILE *stream)
{
	if(stream == NULL)
		return NULL;

	if(stream->used)
		fclose(stream);

	return fopen_internal(path, mode, stream);
}

void clearerr(FILE *stream)
{
	stream->eof = 0;
	stream->error = 0;
}

int feof(FILE *stream)
{
	return stream->eof;
}

int ferror(FILE *stream)
{
	return stream->error;
}

int fileno(FILE *stream)
{
	return stream->fildes;
}