/* See LICENSE file for copyright and license details. */
#include <endian.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "queue.h"
#include "util.h"

struct type {
	unsigned char     format;
	unsigned int      len;
	TAILQ_ENTRY(type) entry;
};

static TAILQ_HEAD(head, type) head = TAILQ_HEAD_INITIALIZER(head);
static unsigned char addr_format = 'o';
static off_t skip = 0;
static off_t max = -1;
static size_t linelen = 1;

static void
printaddress(off_t addr)
{
	char fmt[] = "%07j#";

	if (addr_format == 'n') {
		fputc(' ', stdout);
	} else {
		fmt[4] = addr_format;
		printf(fmt, (intmax_t)addr);
	}
}

static void
printchunk(unsigned char *s, unsigned char format, size_t len) {
	long long res, basefac;
	size_t i;
	char fmt[] = " %0*ll#";

	const char *namedict[] = {
		"nul", "soh", "stx", "etx", "eot", "enq", "ack",
		"bel", "bs",  "ht",  "nl",  "vt",  "ff",  "cr",
		"so",  "si",  "dle", "dc1", "dc2", "dc3", "dc4",
		"nak", "syn", "etb", "can", "em",  "sub", "esc",
		"fs",  "gs",  "rs",  "us",  "sp",
	};
	const char *escdict[] = {
		['\0'] = "\\0", ['\a'] = "\\a",
		['\b'] = "\\b", ['\t'] = "\\t",
		['\n'] = "\\n", ['\v'] = "\\v",
		['\f'] = "\\f", ['\r'] = "\\r",
	};

	switch (format) {
	case 'a':
		*s &= ~128; /* clear high bit as required by standard */
		if (*s < LEN(namedict) || *s == 127) {
			printf(" %3s", (*s == 127) ? "del" : namedict[*s]);
		} else {
			printf(" %3c", *s);
		}
		break;
	case 'c':
		if (strchr("\a\b\t\n\v\f\r\0", *s)) {
			printf(" %3s", escdict[*s]);
		} else {
			printf(" %3c", *s);
		}
		break;
	default:
		res = 0;
		basefac = 1;
#if __BYTE_ORDER == __BIG_ENDIAN
		for (i = len; i; i--) {
			res += s[i - 1] * basefac;
#else
		for (i = 0; i < len; i++) {
			res += s[i] * basefac;
#endif
			basefac <<= 8;
		}
		fmt[6] = format;
		printf(fmt, (int)(3 * len + len - 1), res);
	}
}

static void
printline(unsigned char *line, size_t len, off_t addr)
{
	struct type *t = NULL;
	size_t i;
	int first = 1;

	if (TAILQ_EMPTY(&head))
		goto once;
	TAILQ_FOREACH(t, &head, entry) {
once:
		if (first) {
			printaddress(addr);
			first = 0;
		} else {
			printf("%*c", (addr_format == 'n') ? 1 : 7, ' ');
		}
		for (i = 0; i < len; ) {
			printchunk(line + i, t ? t->format : 'o',
			           MIN(len - i, t ? t->len : 4));
			i += MIN(len - i, t ? t->len : 4);
		}
		fputc('\n', stdout);
		if (TAILQ_EMPTY(&head) || (!len && !first))
			break;
	}
}

static void
od(FILE *fp, char *fname, int last)
{
	static unsigned char *line;
	static size_t lineoff;
	size_t i;
	unsigned char buf[BUFSIZ];
	static off_t addr;
	size_t buflen;

	while (skip - addr) {
		buflen = fread(buf, 1, MIN(skip - addr, BUFSIZ), fp);
		addr += buflen;
		if (feof(fp) || ferror(fp))
			return;
	}
	if (!line)
		line = emalloc(linelen);

	while ((buflen = fread(buf, 1, max >= 0 ?
	                       max - (addr - skip) : BUFSIZ, fp))) {
		for (i = 0; i < buflen; i++, addr++) {
			line[lineoff++] = buf[i];
			if (lineoff == linelen) {
				printline(line, lineoff, addr - lineoff + 1);
				lineoff = 0;
			}
		}
	}
	if (lineoff)
		printline(line, lineoff, addr - lineoff);
	printline((unsigned char *)"", 0, addr);
}

static int
lcm(unsigned int a, unsigned int b)
{
	unsigned int c, d, e;

	for (c = a, d = b; c ;) {
		e = c;
		c = d % c;
		d = e;
	}

	return a / d * b;
}

static void
usage(void)
{
	eprintf("usage: %s", argv0);
}

int
main(int argc, char *argv[])
{
	FILE *fp;
	struct type *t;
	int ret = 0;
	char *s;

	ARGBEGIN {
	case 'A':
		s = EARGF(usage());
		if (strlen(s) != 1 || !strchr("doxn", s[0]))
			usage();
		addr_format = s[0];
		break;
	case 'j':
		if ((skip = parseoffset(EARGF(usage()))) < 0)
			usage();
		break;
	case 'N':
		if ((max = parseoffset(EARGF(usage()))) < 0)
			usage();
		break;
	case 't':
		s = EARGF(usage());
		for (; *s; s++) {
			t = emalloc(sizeof(struct type));
			switch (*s) {
			case 'a':
			case 'c':
				t->format = *s;
				t->len = 1;
				TAILQ_INSERT_TAIL(&head, t, entry);
				break;
			case 'd':
			case 'o':
			case 'u':
			case 'x':
				t->format = *s;
				/* todo: allow multiple digits */
				if (*(s+1) > '0' || *(s+1) <= '9') {
					t->len = *(s+1) - '0';
					s++;
				} else {
					switch (*(s + 1)) {
					case 'C':
						t->len = sizeof(char);
						break;
					case 'S':
						t->len = sizeof(short);
						break;
					case 'I':
						t->len = sizeof(int);
						break;
					case 'L':
						t->len = sizeof(long);
						break;
					default:
						t->len = 4;
					}
				}
				TAILQ_INSERT_TAIL(&head, t, entry);
				break;
			default:
				usage();
			}
		}
		break;
	case 'v':
		/* always set - use uniq(1) to handle duplicate lines */
		break;
	default:
		usage();
	} ARGEND;

	/* line length is lcm of type lengths and >= 16 by doubling */
	TAILQ_FOREACH(t, &head, entry)
		linelen = lcm(linelen, t->len);
	if (TAILQ_EMPTY(&head))
		linelen = 16;
	while (linelen < 16)
		linelen *= 2;

	if (!argc) {
		od(stdin, "<stdin>", 1);
	} else {
		for (; *argv; argc--, argv++) {
			if (!strcmp(*argv, "-")) {
				*argv = "<stdin>";
				fp = stdin;
			} else if (!(fp = fopen(*argv, "r"))) {
				weprintf("fopen %s:", *argv);
				ret = 1;
				continue;
			}
			od(fp, *argv, (!*(argv + 1)));
			if (fp != stdin && fshut(fp, *argv))
				ret = 1;
		}
	}

	ret |= fshut(stdin, "<stdin>") | fshut(stdout, "<stdout>") |
	       fshut(stderr, "<stderr>");

	return ret;
}