/*
 * Bobbi January 2020
 *
 * TODO: Fix bugs!!!!
 * TODO: Sort by type, combinations etc.
 * TODO: Improve checking code
 */

#pragma debug 25	/* Enable stack checking */
#pragma lint -1

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <orca.h>
#include <gsos.h>
#include <prodos.h>


#define DEBUG           /* Enable additional debug printout */
#define CHECK		/* Perform additional integrity checking */

typedef unsigned char uchar;
typedef unsigned int uint;

#define NMLEN 15	/* Length of filename */
#define MAXFILES 1000	/* Max files per directory */

/*
 * ProDOS directory header
 * See ProDOS-8 Tech Ref pp. 152
 */
struct pd_dirhdr {
	uchar	typ_len;
	char	name[NMLEN];
	char	reserved[8];
	uchar	ctime[4];
	uchar	vers;
	uchar	minvers;
	uchar	access;
	uchar	entlen;
	uchar	entperblk;
	uchar	filecnt[2];
	uchar	parptr[2];	/* Bitmap pointer in volume dir */
	uchar	parentry;	/* Total blocks LSB in volume dir */
	uchar	parentlen;	/* Total blocks MSB in volume dir */
};

/*
 * ProDOS file entry
 * See ProDOS-8 Tech Ref pp. 155
 */
struct pd_dirent {
	uchar	typ_len;
	char	name[NMLEN];
	uchar 	type;
	uchar	keyptr[2];
	uchar	blksused[2];
	uchar	eof[3];
	uchar	ctime[4];
	uchar	vers;
	uchar	minvers;
	uchar	access;
	uchar	auxtype[2];
	uchar	mtime[4];
	uchar	hdrptr[2];
};

#define BLKSZ 512	/* 512 byte blocks */
#define PTRSZ 4		/* 4 bytes of pointers at beginning of each blk */

/*
 * Linked list of directory blocks read from disk
 * Original directory block is stored in data[]
 * Directory block for sorted directory is stored in sorteddata[]
 */
struct block {
	char data[BLKSZ];         /* Original contents of block */
	char sorteddata[BLKSZ];   /* Content block for sorted dir */
	uint blocknum;            /* Block number on disk */
	struct block *next;
};

/*
 * Entry for array of filenames used by qsort()
 */
struct fileent {
	char name[NMLEN+1]; /* Name converted to upper/lower case */
	uchar blockidx;     /* Index of dir block (1,2,3 ...)  */
	uchar entrynum;	    /* Entry within the block */
};

/* Globals */
static struct block *blocks = NULL;
static struct fileent filelist[MAXFILES];
static uint numfiles = 0;
static uchar entsz;              /* Bytes per file entry */
static uchar entperblk;          /* Number of entries per block */
static char buf[BLKSZ];          /* General purpose scratch buffer */
static uchar dowrite = 0;
static uchar doreverse = 0;
static uchar doverbose = 0;

static uint stack; // DEBUG

//#define STACK(msg) asm {tsc; sta stack }; fputs(msg, stdout); fputs(" ", stdout); pr_int(stack); putchar('\n');

/* Prototypes */
void prerr(char *s);
void reverse(char *s);
void itoa(int n, char s[]);
void uitoa(uint n, char s[]);
void pr_int(int a);
void pr_uint(uint a);
void print_uint(uint i);
int  readdiskblock(uchar device, uint blocknum, char *buf);
int  writediskblock(uchar device, uint blocknum, char *buf);
void fixcase(char *in, char *out, uchar minvers, uchar vers);
int  readdir(uint device, uint blocknum);
int  compare(const void *a, const void *b);
void sortlist(void);
void printlist(void);
void copyent(uint srcblk, uint srcent, uint dstblk, uint dstent, uint device);
void sortblocks(uint device);
int  writedir(uchar device);
void freeblocks(void);
void usage(void);

/* Print error string to stderr */
void prerr(char *s) {
	fputs(s, stderr);
	fputs("\n", stderr);
}

/* Reverse the characters of the string s */
void reverse(char *s) {
	char buf[10];
	int l = strlen(s);
	for (int i=0; i<l; ++i)
		buf[i] = s[i];
	for (int i=0; i<l; ++i)
		s[i] = buf[l-i-1];
}

/* Stolen from K&R 2nd Ed. pp 64 */
void itoa(int n, char s[]) {
	int i, sign;

	if ((sign = n) < 0)
		n = -1;
	i = 0;
	do {
		s[i++] = n % 10 + '0';
	} while ((n /= 10) > 0);
	if (sign < 0)
		s[i++] = '-';
	s[i] = '\0';
	reverse(s);
}

/* Unsigned verson of itoa() */
void uitoa(uint n, char s[]) {
	int i;

	i = 0;
	do {
		s[i++] = n % 10 + '0';
	} while ((n /= 10) > 0);
	s[i] = '\0';
	reverse(s);
}

/* Print an integer */
void pr_int(int a) {
	char buf[10];
	itoa(a, buf);
	fputs(buf, stdout);
}

/* Print an unsigned integer */
void pr_uint(unsigned int a) {
	char buf[10];
	uitoa(a, buf);
	fputs(buf, stdout);
}

/*
 * Read block from disk using ProDOS call
 * buf must point to buffer with at least 512 bytes
 */
int readdiskblock(uchar device, uint blocknum, char *buf) {
#ifdef DEBUG
	fputs("Reading dev ", stdout);
	pr_int(device);
	fputs(" block ", stdout);
	pr_uint(blocknum);
	putchar('\n');
#endif
	BlockRec br;
	br.blockDevNum = device;
	br.blockDataBuffer = buf;
	br.blockNum = blocknum;
	READ_BLOCK(&br);
	int rc = toolerror();
	if (rc) {
		fprintf(stderr, "READ_BLOCK failed, err=%x\n", rc);
		return -1;
	}
	return 0;
}

/*
 * Write block from disk using ProDOS call
 * buf must point to buffer with at least 512 bytes
 */
int writediskblock(uchar device, uint blocknum, char *buf) {
#ifdef DEBUG
	fputs("Writing dev ", stdout);
	pr_int(device);
	fputs(" block ", stdout);
	pr_uint(blocknum);
	putchar('\n');
#endif
	DIORecGS dr;
	dr.pCount = 6;
	dr.devNum = device;
	dr.buffer = buf;
	dr.requestCount = BLKSZ;
	dr.startingBlock = blocknum;
	dr.blockSize = BLKSZ;
	DWriteGS(&dr);
	if (dr.transferCount != BLKSZ)
		return -1;
	return 0;
}

/*
 * Uses the vers and minvers fields of the directory entry
 * as a bitmap representing which characters are upper and which are
 * lowercase
 */
void fixcase(char *in, char *out, uchar minvers, uchar vers) {
	uchar idx = 0;
	if (!(vers&0x80)) {
		for (idx=0; idx<NMLEN; ++idx)
			out[idx] = in[idx];
		return;
	}
	vers <<= 1;
	for (int i=0; i<7; ++i) {
		out[idx++] = ((vers&0x80) ? tolower(in[idx]) : in[idx]);
		vers <<= 1;
	}
	for (int i=0; i<8; ++i) {
		out[idx++] = ((minvers&0x80) ? tolower(in[idx]) : in[idx]);
		minvers <<= 1;
	}
}

/*
 * Read the first block of a directory and deduce the device ID and block
 * number of the first block of the directory.
 */
uchar firstblk(char *dirname, uchar *device, uint *block) {
	int fp;
	uchar rv = 0;

	fp = open(dirname, O_RDONLY);
	if (!fp) {
		fprintf(stderr, "Error opening dir %s\n", dirname);
		rv = 1;
		goto ret;
	}

	ssize_t len = read(fp, buf, BLKSZ);
	if (len != BLKSZ) {
		fprintf(stderr, "Error reading first block of dir %s", dirname);
		rv = 1;
		goto ret;
	}

	struct stat st;
	if (stat(dirname, &st) == -1) {
		fprintf(stderr, "Can't stat %s\n", dirname);
		exit(1);
	}

	if (!S_ISDIR(st.st_mode)) {
		fprintf(stderr, "%s is not a directory\n", dirname);
		exit(1);
	}

	*device = st.st_dev;

	struct pd_dirhdr *hdr = (struct pd_dirhdr*)(buf + PTRSZ);

	/* Detect & handle volume directory */
	if ((hdr->typ_len & 0xf0) == 0xf0) {
		*block = 2;
		goto ret;
	}

#ifdef CHECK
	if ((hdr->typ_len & 0xf0) != 0xe0) {
		prerr("Bad storage type");
		rv = 1;
		goto ret;
	}
#endif

	/* Handle subdirectory */
	uint parentblk    = hdr->parptr[0] + 256U * hdr->parptr[1];
	uint parententry  = hdr->parentry;
	uint parententlen = hdr->parentlen;

	/* Read parent directory block */
	if (readdiskblock(*device, parentblk, buf) == -1) {
		fprintf(stderr, "Can't read parent directory for %s", dirname);
		rv = 1;
		goto ret;
	}

	struct pd_dirent *ent =
	  (struct pd_dirent *)(buf + PTRSZ + (parententry-1) * parententlen);

	*block = ent->keyptr[0] + 256U * ent->keyptr[1];

ret:
	if (fp)
		close(fp);
	return rv;
}

/*
 * Read a directory, store the raw directory blocks in a linked list
 * and build filelist[] in preparation for sorting. 
 * device is the device number containing the directory
 * blocknum is the block number of the first block of the directory
 */
int readdir(uint device, uint blocknum) {
	uchar blkcnt = 1;
	uint hdrblknum = blocknum;

	blocks = (struct block*)malloc(sizeof(struct block));
	if (!blocks) {
		prerr("Unable to allocate memory");
		return 1;
	}
	struct block *curblk = blocks;
	curblk->next = NULL;
	curblk->blocknum = blocknum;

	if (readdiskblock(device, blocknum, curblk->data) == -1) {
		fprintf(stderr, "Error reading dir block %d\n", blkcnt);
		return 1;
	}

	struct pd_dirhdr *hdr = (struct pd_dirhdr*)(curblk->data + PTRSZ);

	entsz           = hdr->entlen;
	entperblk       = hdr->entperblk;
	uint filecount  = hdr->filecnt[0] + 256U * hdr->filecnt[1];

	/* Copy pointers and header to sorteddata[], zero the rest */
	bzero(curblk->sorteddata, BLKSZ);
	memcpy(curblk->sorteddata, curblk->data, PTRSZ + entsz);


#ifdef DEBUG
	fputs("entsz=", stdout);
	pr_uint(entsz);
	putchar('\n');
	fputs("entperblk=", stdout);
	pr_uint(entperblk);
	putchar('\n');
	fputs("filecount=", stdout);
	pr_uint(filecount);
	putchar('\n');
#endif

// TODO: Add a check that the filecount is correct

#ifdef CHECK
	if (entsz != 0x27) {
		prerr("Error - bad entry size");
		return 1;
	}
	if (entperblk != 0x0d) {
		prerr("Error - bad entries/block");
		return 1;
	}
#endif
	uint idx = entsz + PTRSZ; /* Skip header */
	uchar blkentries = 2;
	uchar entries = 0;

	static char namebuf[NMLEN];

	while (entries < filecount) {
		struct pd_dirent *ent = (struct pd_dirent*)(curblk->data + idx);
		if (ent->typ_len != 0) {
			fixcase(ent->name, namebuf, ent->vers, ent->minvers);
			for (uchar i=0; i<NMLEN+1; ++i)
				filelist[numfiles].name[i] = '\0';
			for (uchar i=0; i<(ent->typ_len & 0x0f); ++i)
				filelist[numfiles].name[i] = namebuf[i];
			filelist[numfiles].blockidx = blkcnt;
			filelist[numfiles].entrynum = blkentries;
#ifdef CHECK
			uint keyblk = ent->keyptr[0] + 256U * ent->keyptr[1];
			uint hdrblk = ent->hdrptr[0] + 256U * ent->hdrptr[1];
			if (hdrblk != hdrblknum) {
				fprintf(stderr,
				        "%s: Header ptr %u should be %u\n",
				        namebuf, hdrblk, hdrblknum);
			}
			if ((ent->typ_len & 0xf0) == 0xd0) {
				if (readdiskblock(device, keyblk, buf) == -1) {
					fprintf(stderr,
					        "Error reading blk %u\n",
					        keyblk);
					return 1;
				}
				hdr = (struct pd_dirhdr*)(buf + PTRSZ);
				uchar parentry = hdr->parentry;
				uchar parentlen = hdr->parentlen;
				uint parblk =
				  hdr->parptr[0] + 256U * hdr->parptr[1];

				if (parblk != blocknum) {
					prerr("Bad parent block number");
					return 1;
				}
				if (parentry != blkentries) {
					prerr("Bad parent block entry num");
					return 1;
				}
				if (parentlen != 0x27) {
					prerr("Bad parent entry length");
					return 1;
				}
				char *dirname = buf + 0x05;
				if (strncmp(dirname, ent->name, NMLEN)) {
					prerr("Subdirectory name mismatch");
					return 1;
				}
			}
#endif
			++numfiles;
			if (numfiles == MAXFILES) {
				prerr("Too many files");
				return 1;
			}
			++entries;
		}
		if (entries < filecount) {
			if (blkentries == entperblk) {
				blocknum =
				  curblk->data[0x02] + 256U*curblk->data[0x03];
				curblk->next =
				  (struct block*)malloc(sizeof(struct block));
				if (!curblk->next) {
					prerr("Unable to allocate memory");
					return 1;
				}
				curblk = curblk->next;
				curblk->next = NULL;
				curblk->blocknum = blocknum;
				++blkcnt;
				if (readdiskblock(device,
				                  blocknum,
				                  curblk->data) == -1) {
					fprintf(stderr,
					        "Error reading dir block %d\n",
					         blkcnt);
					return 1;
				}
				/* Copy ptrs to sorteddata[], zero the rest */
				bzero(curblk->sorteddata, BLKSZ);
				memcpy(curblk->sorteddata, curblk->data, PTRSZ);
				blkentries = 1;
				idx = PTRSZ;
			} else {
				++blkentries;
				idx += entsz;
			}
		}
	}
	return 0;
}

/*
 * Compare two filenames
 */
int compare(const void *a, const void *b) {
	int rc;
	rc = strncmp(((struct fileent*)a)->name,
	             ((struct fileent*)b)->name, 15);
	return (doreverse ? -rc : rc);
}

/*
 * Sort filelist[]
 */
void sortlist(void) {
	qsort(filelist, numfiles, sizeof(struct fileent), compare);
}

/*
 * Print the file info stored in filelist[]
 */
void printlist(void) {
	fputs("numfiles=", stdout);
	pr_int(numfiles);
	putchar('\n');
	for(uint i=0; i<numfiles; ++i) {
		fputs("blk=", stdout);
		pr_int(filelist[i].blockidx);
		fputs(" ent=", stdout);
		pr_int(filelist[i].entrynum);
		putchar('\t');
		fputs(filelist[i].name, stdout);
		putchar('\n');
	}
}

/*
 * Copy a file entry from one srcblk, srcent to dstblk, dstent
 * All indices are 1-based.
 */
void copyent(uint srcblk, uint srcent, uint dstblk, uint dstent, uint device) {

	if (doverbose) {
		fputs("  from blk ", stdout);
		pr_uint(srcblk);
		fputs(" entry ", stdout);
		pr_uint(srcent);
		putchar('\n');
		fputs("  to blk ", stdout);
		pr_uint(dstblk);
		fputs(" entry ", stdout);
		pr_uint(dstent);
		putchar('\n');
	}

	struct block *source = blocks;
	struct block *dest   = blocks;
	while (--srcblk > 0)
		source = source->next;
	while (--dstblk > 0)
		dest = dest->next;
	char *srcptr =  source->data + PTRSZ + (srcent-1) * entsz;
	char *dstptr =  dest->sorteddata + PTRSZ + (dstent-1) * entsz;
	memcpy(dstptr, srcptr, entsz);

	/* For directories, update the parent dir entry number */
	struct pd_dirent *ent = (struct pd_dirent*)dstptr;
	if ((ent->typ_len & 0xf0) == 0xd0) {
		uint block = ent->keyptr[0] + 256U * ent->keyptr[1];
		if (readdiskblock(device, block, buf) == -1) {
			prerr("Can't read subdirectory");
			exit(1);
		}
		struct pd_dirhdr *hdr = (struct pd_dirhdr*)(buf + PTRSZ);
		hdr->parentry = dstent;
		if (dowrite) {
			if (writediskblock(device, block, buf) == -1) {
				prerr("Can't write subdirectory");
				exit(1);
			}
		} else {
			if (doverbose)
				puts("Not writing updated subdir to disk");
		}
	}
}

/*
 * Use the sorted list in filelist[] to create a sorted set of directory
 * blocks.  Note that the block and entry numbers are 1-based indices.
 */
void sortblocks(uint device) {
	uchar destblk = 1;
	uchar destentry = 2; /* Skip header on first block */
	for(uint i=0; i<numfiles; ++i) {
		puts(filelist[i].name);
		copyent(filelist[i].blockidx, filelist[i].entrynum,
		        destblk, destentry, device);
		if (destentry++ == entperblk) {
			++destblk;
			destentry = 1;
		}
	}
}

/*
 * Write out the sorted directory
 */
int writedir(uchar device) {
	struct block *i = blocks;
	while (i) {
		if(writediskblock(device, i->blocknum, i->sorteddata) == -1) {
			fprintf(stderr, "Can't write block %u\n", i->blocknum);
			return 1;
		}
		i = i->next;
	}
	return 0;
}

/*
 * Walk through the linked list freeing memory
 */
void freeblocks(void) {
	struct block *i = blocks, *j;
	while (i) {
		j = i->next;
		free(i);
		i = j;
	}
}

void usage(void) {
	prerr("usage: sortdir [-rwv] path\n");
	prerr("  Options: -r   Reverse sort order");
	prerr("           -w   Enable writing to disk");
	prerr("           -v   Verbose output\n");
	exit(2);
}

#if 0
void debuglinkedlist(void) {
	puts("============================================");
	struct block *b = blocks;
	while (b) {
		pr_uint((uint)b);
		puts("----");
		b = b->next;
	}
}
#endif

int main(int argc, char *argv[]) {
	if (argc < 2) {
		usage();
		exit(1);
	}
	int opt;
	while ((opt = getopt(argc, argv, "rwv")) != -1) {
		switch (opt) {
		case 'r':
			doreverse = 1;
			break;
		case 'w':
			dowrite = 1;
			break;
		case 'v':
			doverbose = 1;
			break;
		default:
			usage();
		}
	}

	if (optind >= argc)
		usage();
	
	uchar dev;
	uint blk;
	if (firstblk(argv[optind], &dev, &blk) != 0) {
		exit(1);
	}
	uchar err = readdir(dev, blk);
	if (!err) {
		if (doverbose)
			printlist();
		sortlist();
		sortblocks(dev);
		if (dowrite)
			err = writedir(dev);
		else
			if (doverbose)
				puts("Not writing to disk");
	}
	freeblocks();
	return err;
}