/*
 * params.c -- Device parameter file handling.
 *
 * Copyright (C) 2016 Tomasz Kramkowski <tk@the-tk.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <ctype.h>

#include "eprintf.h"
#include "params.h"
#include "util.h"

/* TODO: make this dynamic */
#define SZMAX_PFILE 1024

#ifndef DATADIR
#define DATADIR "hktool"
#endif

/* readparams: read a file's param definition */
static void readparams(struct flashparams *fp, const char *file)
{
	char cont[SZMAX_PFILE], *pos;
	size_t contsz;
	FILE *f;

	assert(file);
	assert(fp);

	f = fopen(file, "r");
	if (f == NULL)
		eprintf("Could not open '%s':", file);

	contsz = fread(cont, 1, SZMAX_PFILE, f);
	if (contsz >= sizeof cont)
		eprintf("Parameter file '%s' is longer than %zu", file, sizeof cont - 1);

	pos = cont;
	for (int i = 0; i < 4; i++) {
		char *end;
		unsigned long long val;

		errno = 0;
		val = strtoull(pos, &end, 0);
		if (pos == end)
			eprintf("Parameter file '%s' is malformed (offset:%zd not a number)", file, pos - cont);
		pos = end;

		if (errno == ERANGE || val > SIZE_MAX)
			eprintf("Parameter file '%s' is malformed (offset:%zd number too large)", file, pos - cont);

		switch (i) {
		case 0: fp->memsz = val; break;
		case 1: fp->blksz = val; break;
		case 2: fp->cmdsz = val; break;
		case 3: fp->addrshft = val; break;
		}
	}

	fclose(f);
}

static void printcname(const char *file)
{
	bool wasspace;
	FILE *f;
	int c, field;

	assert(file);

	f = fopen(file, "r");
	if (f == NULL) {
		printf(": Malformed file '%s'", file);
		return;
	}

	field = 0;
	wasspace = false;
	while (c = fgetc(f), c != EOF) {
		if (isspace(c)) {
			wasspace = true;
			continue;
		}
		if (wasspace) {
			wasspace = false;
			field++;
		}
		if (field >= 4) {
			ungetc(c, f);
			break;
		}
	}

	if (c == EOF)
		return;

	printf(": ");
	while (c = fgetc(f), c != EOF)
		if (c != '\n')
			putchar(c);
}

/* getparams: Locate a parameter file and load it or show names of all files */
bool getparams(struct flashparams *fp, const char *name)
{
	char pathbuf[PATH_MAX], *dirname, *fullpath;
	struct dirent *de;
	size_t pathsize;
	bool found;
	DIR *dir;

	assert((fp == NULL && name == NULL) || (fp != NULL && name != NULL));

	fullpath = pathbuf;
	pathsize = sizeof pathbuf;

	dirname = getenv("HKTOOL_DATADIR");
	if (dirname == NULL || strlen(dirname) == 0)
		dirname = DATADIR;

	dir = opendir(dirname);
	if (dir == NULL)
		eprintf("Could not open directory '%s':", dirname);

	if (name == NULL)
		printf("Searching '%s' for Device Parameter Files:\n", dirname);

	found = false;
	while (errno = 0, de = readdir(dir), de != NULL) {
		bool ismatch, doprint;

		doprint = name == NULL;
		if (doprint)
			ismatch = strcmp(de->d_name, name) == 0;
		else
			ismatch = false;

		if (doprint || ismatch) {
			int size;

			size = snprintf(NULL, 0, "%s/%s", dirname, de->d_name);
			assert(size > 0);
			if ((size_t)size > pathsize) {
				if (fullpath == pathbuf)
					fullpath = NULL;
				fullpath = erealloc(fullpath, size);
				pathsize = size;
			}
			size = snprintf(fullpath, pathsize, "%s/%s", dirname, de->d_name);
			assert(size > 0);
			assert((size_t)size < pathsize);
		}

		if (doprint) {
			printf("%s", de->d_name);
			printcname(fullpath);
			putchar('\n');
			continue;
		};

		if (!ismatch)
			continue;


		readparams(fp, fullpath);
		found = true;
		errno = 0;
		break;
	}
	if (errno)
		weprintf("Could not read directory '%s':", dirname);

	if (fullpath != pathbuf)
		free(fullpath);

	if (closedir(dir) == -1)
		eprintf("Could not close directory '%s':", dirname);

	return found;
}