/*
 * Copyright 2016-present Facebook. All Rights Reserved.
 *
 * linelogcli.c: a simple CLI tool manipulating a linelog file
 *
 * This software may be used and distributed according to the terms of the
 * GNU General Public License version 2 or any later version.
 */

/* this tool is mainly for testing and debugging purpose. it does not have
   proper error handling and is not very user-friendly. */

#ifndef _XOPEN_SOURCE
#define _XOPEN_SOURCE 500 /* ftruncate */
#endif

#include "linelog.c" /* unusual but we want to access some private structs */
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#define ensure(expr) if (!(expr)) { \
	fprintf(stderr, "unexpected: %s\n at line %d\n errno = %d %s", \
		#expr, __LINE__, errno, strerror(errno)); \
	closefile(); exit(-1); }

#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
const size_t UNIT_SIZE = 1;
#else
const size_t UNIT_SIZE = 0x1000; /* 4KB, used when resizing the file */
#endif

static linelog_buf buf;
static linelog_annotateresult ar;
static int fd = -1;
static size_t maplen;
static const char *filename;

static const char helptext[] =
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
	"(built for fuzz testing)\n"
#endif
	"usage: linelogcli FILE CMDLIST\n"
	"where  CMDLIST := CMD | CMDLIST CMD\n"
	"       CMD := init | info | dump | ANNOTATECMD | REPLACELINESCMD | "
		"GETALLLINESCMD\n"
	"       ANNOTATECMD := annotate REV | annotate -\n"
	"       REPLACELINESCMD := replacelines rev a1:a2 b1:b2\n"
	"       GETALLLINESCMD := getalllines offset1:offset2\n";

static void closefile(void) {
	if (buf.data) {
		ensure(msync(buf.data, buf.size, MS_ASYNC) == 0);
		ensure(munmap(buf.data, maplen) == 0);
		buf.data = NULL;
		buf.size = 0;
	}
	if (fd != -1) {
		ensure(close(fd) == 0);
		fd = -1;
	}
}

static void openfile(void) {
	closefile();
	ensure((fd = open(filename, O_RDWR | O_CREAT, 0644)) != -1);

	struct stat st;
	ensure(fstat(fd, &st) == 0);

	maplen = (st.st_size == 0 ? 1 : (size_t)st.st_size);
	void *p = mmap(NULL, maplen, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	ensure(p != MAP_FAILED);

	buf.data = p;
	buf.size = (size_t)st.st_size;
}

static void resizefile(size_t size) {
	closefile();
	ensure((fd = open(filename, O_RDWR | O_CREAT, 0644)) != -1);
	ensure(ftruncate(fd, (off_t)size) == 0);
	openfile();
}

/* handle LINELOG_RESULT_ENEEDRESIZE automatically */
#define eval(result, expr) while (1) { \
	result = (expr); \
	if (result != LINELOG_RESULT_ENEEDRESIZE) \
		break; \
	resizefile((buf.neededsize / UNIT_SIZE + 1) * UNIT_SIZE); }

int cmdinit(const char *args[]) {
	(void)args;
	linelog_result r;
	eval(r, linelog_clear(&buf));
	if (r == LINELOG_RESULT_OK)
		printf("init: okay\n");
	return r;
}

int cmdinfo(const char *args[]) {
	(void)args;
	size_t size = linelog_getactualsize(&buf);
	linelog_revnum rev = linelog_getmaxrev(&buf);
	printf("info: maxrev = %u, size = %lu\n",
			(unsigned)rev, (unsigned long)size);
	return 0;
}

int cmdannotate(const char *args[]) {
	linelog_result r = LINELOG_RESULT_OK;
	unsigned rev = 0;
	if (sscanf(args[0], "%u", &rev) == 1) {
		printf("annotate: run annotate for rev %u\n", rev);
		eval(r, linelog_annotate(&buf, &ar, (linelog_revnum)rev));
	}
	if (r == LINELOG_RESULT_OK) {
		printf("annotate: %u lines, endoffset %u\n",
				ar.linecount, ar.lines[ar.linecount].offset);
		for (uint32_t i = 0; i < ar.linecount; ++i) {
			linelog_lineinfo l = ar.lines[i];
			printf("  %u: rev %u, line %u, offset %u\n",
					i, l.rev, l.linenum, l.offset);
		}
	}
	return r;
}

#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
static void doublecheckannotateresult(linelog_revnum rev) {
	/* backup current ar for later comparison */
	linelog_annotateresult ar2 = ar;
	size_t arsize = (ar.linecount + 1) * sizeof(linelog_lineinfo);
	ar2.lines = malloc(arsize);
	ar2.maxlinecount = ar2.linecount + 1;
	ensure(ar2.lines != NULL);
	memcpy(ar2.lines, ar.lines, arsize);
	linelog_result r;
	eval(r, linelog_annotate(&buf, &ar2, rev));
	if (r != LINELOG_RESULT_OK || (ar.linecount == ar2.linecount &&
				memcmp(ar2.lines, ar.lines, arsize) == 0)) {
		free(ar2.lines);
		return;
	}
	fprintf(stderr, "unexpected: annotate results mismatch\n");
	int cmddump(const char *args[]);
	cmddump(NULL);

	linelog_linenum maxlc = ar.linecount > ar2.linecount
		? ar.linecount : ar2.linecount;
	fprintf(stderr, "ar %d lines | ar2 %d lines\n",
			ar.linecount, ar2.linecount);
	for (uint32_t i = 0; i <= maxlc; ++i) {
		linelog_lineinfo l[2];
		memset(l, -1, sizeof(l));
		if (i <= ar.linecount)
			l[0] = ar.lines[i];
		if (i <= ar2.linecount)
			l[1] = ar2.lines[i];
		char ch = memcmp(l, l + 1, sizeof(l[0])) ? '!' : '=';
		fprintf(stderr, "%c %u: %u %u %u | %u %u %u\n",
				ch, i,
				l[0].rev, l[0].linenum, l[0].offset,
				l[1].rev, l[1].linenum, l[1].offset);
	}
	abort();
}
#endif

int cmdreplacelines(const char *args[]) {
	linelog_result r;
	unsigned rev = 0, b1 = 0, b2 = 0;
	int a1 = 0, a2 = 0;
	sscanf(args[0], "%u", &rev);
	sscanf(args[1], "%d:%d", &a1, &a2);
	sscanf(args[2], "%u:%u", &b1, &b2);
	/* for negative number of a1, a2. use linecount automatically */
	if (a1 < 0)
		a1 = (int)ar.linecount + 1 + a1;
	if (a2 < 0)
		a2 = (int)ar.linecount + 1 + a2;
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
	/* make sure we use clean, up-to-date annotate result. this changes
	   behavior a bit but reduces noise from fuzz testing */
	eval(r, linelog_annotate(&buf, &ar, rev));
	if (r != LINELOG_RESULT_OK)
		return r;
#endif
	eval(r, linelog_replacelines(&buf, &ar, rev,
				(uint32_t)a1, (uint32_t)a2, b1, b2));
	if (r == LINELOG_RESULT_OK) {
		printf("replacelines: rev %u, lines %u:%u -> %u:%u\n",
				rev, a1, a2, b1, b2);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
		/* annotateresult updated by linelog_replacelines should be
		   the same with running linelog_annotate directly */
		doublecheckannotateresult(rev);
#endif
	}
	return r;
}

int cmddump(const char *args[]) {
	(void)args;
	size_t size = linelog_getactualsize(&buf) / INST_SIZE;
	printf("dump:\n");
	for (size_t offset = 1; offset < size; ++offset) {
		linelog_inst i;
		memset(&i, 0, sizeof(i));
		readinst(&buf, &i, offset);
		/* opcode */
		const char *opname = "?";
		if (i.opcode == JGE) {
			if (i.rev == 0) {
				if (i.offset == 0) /* JGE 0 0 => END */
					opname = "END";
				else /* JGE 0 => J */
					opname = "J";
			} else {
				opname = "JGE";
			}
		} else if (i.opcode == JL) {
			opname = "JL";
		} else if (i.opcode == LINE) {
			opname = "LINE";
		}
		printf("  %6u: %-4s ", (unsigned)offset, opname);
		/* operand 1 */
		if (i.rev) {
			printf("%5u ", (unsigned)i.rev);
		} else {
			printf("      ");
		}
		/* operand 2 */
		if (opname[0] == 'E') { /* END */
			printf("\n");
		} else {
			printf("%u\n", (unsigned)i.offset);
		}
	}
	return LINELOG_RESULT_OK;
}

int cmdgetalllines(const char *args[]) {
	unsigned offset1 = 0, offset2 = 0;
	sscanf(args[0], "%u:%u", &offset1, &offset2);

	linelog_result r;
	linelog_annotateresult ar;
	memset(&ar, 0, sizeof(ar));
	eval(r, linelog_getalllines(&buf, &ar, offset1, offset2));
	if (r == LINELOG_RESULT_OK) {
		printf("getalllines: %u lines\n", ar.linecount);
		for (uint32_t i = 0; i < ar.linecount; ++i) {
			linelog_lineinfo l = ar.lines[i];
			printf("  %u: rev %u, line %u, offset %u\n",
					i, l.rev, l.linenum, l.offset);
		}
	}
	linelog_annotateresult_clear(&ar);
	return r;
}

typedef int cmdfunc(const char *args[]);
typedef struct {
	const char *name;
	const char shortname;
	int argcount;
	cmdfunc *func;
} cmdentry;

static cmdentry cmdtable[] = {
	{ "init", 'i', 0, cmdinit },
	{ "info", 'f', 0, cmdinfo },
	{ "annotate", 'a', 1, cmdannotate },
	{ "replacelines", 'r', 3, cmdreplacelines },
	{ "dump", 'd', 0, cmddump },
	{ "getalllines", 'l', 1, cmdgetalllines },
};

const cmdentry *findcmd(const char *name) {
	size_t len = strlen(name);
	for (size_t i = 0; i < sizeof(cmdtable) / sizeof(cmdtable[0]); ++i) {
		if (len == 1 ? name[0] == cmdtable[i].shortname
				: strcmp(name, cmdtable[i].name) == 0)
			return &cmdtable[i];
	}
	return NULL;
}

const char *translateerror(linelog_result result) {
	switch (result) {
		case LINELOG_RESULT_ENOMEM:
			return "NOMEM";
		case LINELOG_RESULT_EILLDATA:
			return "ILLDATA";
		case LINELOG_RESULT_EOVERFLOW:
			return "OVERFLOW";
	}
	return "(unknown)";
}

int main(int argc, char const *argv[]) {
	if (argc < 3) {
		puts(helptext);
		return 1;
	}

	filename = argv[1];
	openfile();
	linelog_annotateresult_clear(&ar);

	for (int i = 2; i < argc; i++) {
		const cmdentry *cmd = findcmd(argv[i]);
		if (!cmd) {
			fprintf(stderr, "%s: unknown command\n", argv[i]);
			continue;
		}
		if (argc - i - 1 < cmd->argcount) {
			fprintf(stderr, "%s: missing argument\n", argv[i++]);
			break;
		}
		linelog_result r = cmd->func(argv + i + 1);
		if (r != LINELOG_RESULT_OK)
			fprintf(stderr, "%s: error %d (%s)\n",
					cmd->name, (int)r, translateerror(r));
		i += cmd->argcount;
	}

	/* truncate the file to actual used size */
	size_t size = linelog_getactualsize(&buf);
	if (size && size != buf.size)
		resizefile(size);

	closefile();
	linelog_annotateresult_clear(&ar);
	return 0;
}