/*
 Author: José Bollo <jobol@nonadev.net>

 https://gitlab.com/jobol/mustach

 SPDX-License-Identifier: ISC
*/

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include <stdlib.h>
#include <stdio.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <libgen.h>

#include "mustach-wrap.h"

static const size_t BLOCKSIZE = 8192;

static const char *errors[] = {
	"??? unreferenced ???",
	"system",
	"unexpected end",
	"empty tag",
	"tag too long",
	"bad separators",
	"too depth",
	"closing",
	"bad unescape tag",
	"invalid interface",
	"item not found",
	"partial not found",
	"undefined tag",
	"too much template nesting"
};

static const char *errmsg = 0;
static int flags = 0;
static FILE *output = 0;

static void help(char *prog)
{
	char *name = basename(prog);
#define STR_INDIR(x) #x
#define STR(x) STR_INDIR(x)
	printf("%s version %s\n", name, STR(VERSION));
#undef STR
#undef STR_INDIR
	printf(
		"\n"
		"USAGE:\n"
		"    %s [FLAGS] <json-file> <mustach-templates...>\n"
		"\n"
		"FLAGS:\n"
		"    -h, --help     Prints help information\n"
		"    -s, --strict   Error when a tag is undefined\n"
		"\n"
		"ARGS: (if a file is -, read standard input)\n"
		"    <json-file>              JSON file with input data\n"
		"    <mustach-templates...>   Template files to instantiate\n",
		name);
	exit(0);
}

static char *readfile(const char *filename, size_t *length)
{
	int f;
	struct stat s;
	char *result;
	size_t size, pos;
	ssize_t rc;

	result = NULL;
	if (filename[0] == '-' &&  filename[1] == 0)
		f = dup(0);
	else
		f = open(filename, O_RDONLY);
	if (f < 0) {
		fprintf(stderr, "Can't open file: %s\n", filename);
		exit(1);
	}

	fstat(f, &s);
	switch (s.st_mode & S_IFMT) {
	case S_IFREG:
		size = s.st_size;
		break;
	case S_IFSOCK:
	case S_IFIFO:
		size = BLOCKSIZE;
		break;
	default:
		fprintf(stderr, "Bad file: %s\n", filename);
		exit(1);
	}

	pos = 0;
	result = malloc(size + 1);
	do {
		if (result == NULL) {
			fprintf(stderr, "Out of memory\n");
			exit(1);
		}
		rc = read(f, &result[pos], (size - pos) + 1);
		if (rc < 0) {
			fprintf(stderr, "Error while reading %s\n", filename);
			exit(1);
		}
		if (rc > 0) {
			pos += (size_t)rc;
			if (pos > size) {
				size = pos + BLOCKSIZE;
				result = realloc(result, size + 1);
			}
		}
	} while(rc > 0);

	close(f);
	if (length != NULL)
		*length = pos;
	result[pos] = 0;
	return result;
}

static int load_json(const char *filename);
static int process(const char *content, size_t length);
static void close_json();

int main(int ac, char **av)
{
	char *t, *f;
	char *prog = *av;
	int s;
	size_t length;

	(void)ac; /* unused */
	flags = Mustach_With_AllExtensions;
	output = stdout;

	for( ++av ; av[0] && av[0][0] == '-' && av[0][1] != 0 ; av++) {
		if (!strcmp(*av, "-h") || !strcmp(*av, "--help"))
			help(prog);
		if (!strcmp(*av, "-s") || !strcmp(*av, "--strict"))
			flags |= Mustach_With_ErrorUndefined;
	}
	if (*av) {
		f = (av[0][0] == '-' && !av[0][1]) ? "/dev/stdin" : av[0];
		s = load_json(f);
		if (s < 0) {
			fprintf(stderr, "Can't load json file %s\n", av[0]);
			if(errmsg)
				fprintf(stderr, "   reason: %s\n", errmsg);
			exit(1);
		}
		while(*++av) {
			t = readfile(*av, &length);
			s = process(t, length);
			free(t);
			if (s != MUSTACH_OK) {
				s = -s;
				if (s < 1 || s >= (int)(sizeof errors / sizeof * errors))
					s = 0;
				fprintf(stderr, "Template error %s (file %s)\n", errors[s], *av);
			}
		}
		close_json();
	}
	return 0;
}

#define MUSTACH_TOOL_JSON_C  1
#define MUSTACH_TOOL_JANSSON 2
#define MUSTACH_TOOL_CJSON   3

#if TOOL == MUSTACH_TOOL_JSON_C

#include "mustach-json-c.h"

static struct json_object *o;
static int load_json(const char *filename)
{
	o = json_object_from_file(filename);
#if JSON_C_VERSION_NUM >= 0x000D00
	errmsg = json_util_get_last_err();
	if (errmsg != NULL)
		return -1;
#endif
	if (o == NULL) {
		errmsg = "null json";
		return -1;
	}
	return 0;
}
static int process(const char *content, size_t length)
{
	return mustach_json_c_file(content, length, o, flags, output);
}
static void close_json()
{
	json_object_put(o);
}

#elif TOOL == MUSTACH_TOOL_JANSSON

#include "mustach-jansson.h"

static json_t *o;
static json_error_t e;
static int load_json(const char *filename)
{
	o = json_load_file(filename, JSON_DECODE_ANY, &e);
	if (o == NULL) {
		errmsg = e.text;
		return -1;
	}
	return 0;
}
static int process(const char *content, size_t length)
{
	return mustach_jansson_file(content, length, o, flags, output);
}
static void close_json()
{
	json_decref(o);
}

#elif TOOL == MUSTACH_TOOL_CJSON

#include "mustach-cjson.h"

static cJSON *o;
static int load_json(const char *filename)
{
	char *t;
	size_t length;

	t = readfile(filename, &length);
	o = t ? cJSON_ParseWithLength(t, length) : NULL;
	free(t);
	return -!o;
}
static int process(const char *content, size_t length)
{
	return mustach_cJSON_file(content, length, o, flags, output);
}
static void close_json()
{
	cJSON_Delete(o);
}

#else
#error "no defined json library"
#endif