/*
 * OSCam WebIf pages generator
 * Copyright (C) 2013 Unix Solutions Ltd.
 *
 * Authors: Georgi Chorbadzhiyski (gf@unixsol.org)
 *
 * 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 <ctype.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libgen.h>

#include "../config.h"
#ifdef WITH_COMPRESS_WEBIF
#include "../minilzo/minilzo.h"
#define USE_COMPRESSION 1
#endif

#define MAX_TEMPLATES 512
static char *index_filename = "pages_index.txt";
static char *defined_file   = "is_defined.txt";
static char *output_pages_c = "pages.c";
static char *output_pages_h = "pages.h";

struct template
{
	char ident[64];
	char file[128];
	char deps[1024];
	uint32_t data_len;
	enum { TXT, BIN } type;
	uint8_t mime_type;
#ifdef USE_COMPRESSION
	uint8_t *buf;
	size_t buf_len;
	uint32_t ident_ofs;
	uint32_t data_ofs;
	uint32_t deps_ofs;
#endif
};

struct templates
{
	unsigned int num;
	struct template data[MAX_TEMPLATES];
};

static struct templates templates;
static FILE *output_file;

__attribute__ ((noreturn)) static void die(const char *s, ...)
{
	va_list args;
	va_start(args, s);
	fprintf(stderr, "ERROR: ");
	vfprintf(stderr, s, args);
	if(s[strlen(s) - 1] != '\n')
		{ fprintf(stderr, "\n"); }
	va_end(args);
	exit(EXIT_FAILURE);
}

static FILE *xfopen(char *filename, char *mode)
{
	FILE *fh = fopen(filename, mode);
	if(!fh)
		{ die("fopen(%s, %s): %s\n", filename, mode, strerror(errno)); }
	return fh;
}

static void readfile(const char *filename, uint8_t **data, size_t *data_len)
{
	struct stat sb;
	if(stat(filename, &sb) != 0)
		{ die("stat(%s): %s\n", filename, strerror(errno)); }
	int fd = open(filename, O_RDONLY);
	if(fd < 0)
		{ die("open(%s): %s\n", filename, strerror(errno)); }
	*data_len = sb.st_size;
	*data = malloc(*data_len);
	if(!*data)
		{ die("%s(%s): can't alloc %zd bytes\n", __func__, filename, *data_len); }
	if(read(fd, *data, *data_len) < 0)
		{ die("read(%d, %zd): %s\n", fd, *data_len, strerror(errno)); }
	close(fd);
}

static bool is_text(char *filename)
{
	char *ext = strchr(basename(filename), '.');
	if(ext)
	{
		ext++;
		if(strcmp(ext, "html") == 0) { return true; }
		else if(strcmp(ext, "json") == 0) { return true; }
		else if(strcmp(ext, "xml")  == 0) { return true; }
		else if(strcmp(ext, "css")  == 0) { return true; }
		else if(strcmp(ext, "svg")  == 0) { return true; }
		else if(strcmp(ext, "js")   == 0) { return true; }
	}
	return false;
}

static uint8_t mime_type_from_filename(char *filename)
{
	char *ext = strchr(basename(filename), '.');
	if(ext)
	{
		ext++;
		// See "enum template_types" bellow
		if(strcmp(ext, "png") == 0) { return 1; }
		else if(strcmp(ext, "gif") == 0) { return 2; }
		else if(strcmp(ext, "ico") == 0) { return 3; }
		else if(strcmp(ext, "jpg") == 0) { return 4; }
	}
	return 0;
}

static void parse_index_file(char *filename)
{
	uint8_t *is_defined = NULL;
	size_t is_defined_len = 0;
	if(access(defined_file, R_OK) != -1)
		readfile(defined_file, &is_defined, &is_defined_len);
	FILE *f = xfopen(filename, "r");
	int max_fields = 3;
	char line[1024];
	while(fgets(line, sizeof(line) - 1, f))
	{
		int field = 0, pos = 0;
		char *ident = "", *file = "", *deps = "";
		int len = strlen(line);
		if(!len || !isalnum((unsigned char)line[0]))  // Skip comments and junk
			{ continue; }
		// Parse text[   ]text[   ]text
		do
		{
			while(line[pos] == ' ' || line[pos] == '\t')  // Skip white space
				{ pos++; }
			if(line[pos] == '\n')
				{ break; }
			int start = pos;
			while(line[pos] != ' ' && line[pos] != '\t' && line[pos] != '\n')  // Data
				{ pos++; }
			switch(++field)
			{
			case 1:
				ident = line + start;
				line[pos] = '\0';
				break;
			case 2:
				file  = line + start;
				line[pos] = '\0';
				break;
			case 3:
				deps  = line + start;
				line[pos] = '\0';
				break;
			}
			if(field >= max_fields)
				{ break; }
			pos++;
		}
		while(pos < len);

		if(deps && strlen(deps) && is_defined){
			if(strstr(deps, ",")){
				int i,def_found=0;
				char *ptr, *saveptr1 = NULL;
				char *deps_sep = strdup(deps);
	 			for(i = 0, ptr = strtok_r(deps_sep, ",", &saveptr1); ptr; ptr = strtok_r(NULL, ",", &saveptr1), i++)
	 			{
					if(strstr((char *)is_defined, ptr))
	 					{ def_found = 1; }
	 			}
				free(deps_sep);
				if(!def_found)
					{ continue; }
			}
			else if( !strstr((char *)is_defined, deps))
				{ continue; }
		}
		if(!strlen(ident) || !strlen(file))
			{ continue; }

#define template_set(var) \
    do { \
        len = strlen(var); \
        pos = sizeof(templates.data[0].var); \
        if (len > pos - 1) \
            die("%s=%s length exceeds maxlen (%d > %d)\n", #var, var, len, pos - 1); \
        snprintf(templates.data[templates.num].var, pos, "%s", var); \
    } while (0)
		template_set(ident);
		template_set(file);
		template_set(deps);

		templates.data[templates.num].type = is_text(file) ? TXT : BIN;
		templates.data[templates.num].mime_type = mime_type_from_filename(file);
		templates.num++;
		if(templates.num == MAX_TEMPLATES - 1)
		{
			die("Too many templates in %s. Maximum is %d. Increase MAX_TEMPLATES!\n",
				filename, MAX_TEMPLATES);
		}
	}
	fclose(f);
}

static void print_template(int tpl_idx)
{
	static bool ifdef_open = 0;
	char *prev_deps = "";
	char *next_deps = "";
	char *ident     = templates.data[tpl_idx].ident;
	char *deps      = templates.data[tpl_idx].deps;
	if(tpl_idx > 0)
		{ prev_deps   = templates.data[tpl_idx - 1].deps; }
	if(tpl_idx + 1 < templates.num)
		{ next_deps   = templates.data[tpl_idx + 1].deps; }
	int deps_len    = strlen(deps);

	// Put guards
	if(deps_len && strcmp(deps, prev_deps) != 0)
	{
		int i, commas = 0;
		for(i = 0; i < deps_len; i++)
		{
			if(deps[i] == ',')
				{ commas++; }
		}
		if(commas == 0)
		{
			fprintf(output_file, "#ifdef %s\n", deps);
		}
		else
		{
			char *ptr, *saveptr1 = NULL;
			char *split_deps = strdup(deps);
			for(i = 0, ptr = strtok_r(split_deps, ",", &saveptr1); ptr; ptr = strtok_r(NULL, ",", &saveptr1), i++)
			{
				if(i == 0)
					{ fprintf(output_file, "#if defined(%s)", ptr); }
				else
					{ fprintf(output_file, " || defined(%s)", ptr); }
			}
			fprintf(output_file, "\n");
			free(split_deps);
		}
		ifdef_open = 1;
	}

#ifdef USE_COMPRESSION
	fprintf(output_file, "\t{ .tpl_name_ofs=%5u, .tpl_data_ofs=%5u, .tpl_deps_ofs=%5u, .tpl_data_len=%5u, .tpl_type=%u }, /* %s %s %s */\n",
			templates.data[tpl_idx].ident_ofs,
			templates.data[tpl_idx].data_ofs,
			templates.data[tpl_idx].deps_ofs,
			templates.data[tpl_idx].data_len,
			templates.data[tpl_idx].mime_type,
			ident,
			templates.data[tpl_idx].file,
			deps
		   );
#else
	fprintf(output_file, "\t{ .tpl_name=\"%s\", .tpl_data=TPL%s, .tpl_deps=\"%s\", .tpl_data_len=%u, .tpl_type=%u },\n",
			ident, ident, deps, templates.data[tpl_idx].data_len, templates.data[tpl_idx].mime_type
		   );
#endif

	if(ifdef_open && strcmp(deps, next_deps) != 0)
	{
		fprintf(output_file, "#endif\n");
		ifdef_open = 0;
	}
}

#ifdef USE_COMPRESSION
static void dump_cbinary(char *var_name, uint8_t *buf, size_t buf_len, size_t obuf_len)
{
	fprintf(output_file, "static const char   *%s     = \"", var_name);
	int i;
	for(i = 0; i < buf_len; i++)
	{
		fprintf(output_file, "\\x%02x", buf[i]);
	}
	fprintf(output_file, "\";\n");
	fprintf(output_file, "static const size_t %s_len  = %zu;\n"  , var_name, buf_len);
	fprintf(output_file, "static const size_t %s_olen = %zu;\n\n", var_name, obuf_len);
}

#define HEAP_ALLOC(var, size) \
    lzo_align_t __LZO_MMODEL var [ ((size) + (sizeof(lzo_align_t) - 1)) / sizeof(lzo_align_t) ]

static HEAP_ALLOC(wrkmem, LZO1X_1_MEM_COMPRESS);
#else

static void dump_text(char *ident, uint8_t *buf, size_t buf_len)
{
	int i;
	fprintf(output_file, "#define TPL%s \\\n\"", ident);
	for(i = 0; i < buf_len; i++)
	{
		switch(buf[i])
		{
		case '\n':
			if(i < buf_len - 1)
				{ fprintf(output_file, "\\n\\\n"); }
			else
				{ fprintf(output_file, "\\n"); }
			break;
		case '\\':
			fprintf(output_file, "\\\\");
			break;
		case '"' :
			fprintf(output_file, "\\\"");
			break;
		default  :
			fprintf(output_file, "%c", buf[i]);
			break;
		}
	}
	fprintf(output_file, "\"\n\n");
}

static void dump_binary(char *ident, uint8_t *buf, size_t buf_len)
{
	fprintf(output_file, "#define TPL%s \\\n\"", ident);
	int i;
	for(i = 0; i < buf_len; i++)
	{
		fprintf(output_file, "\\x%02x", buf[i]);
	}
	fprintf(output_file, "\"\n\n");
}
#endif

int main(void)
{
	int i;

	parse_index_file(index_filename);

	output_file = xfopen(output_pages_h, "w");
	fprintf(output_file, "#ifndef WEBIF_PAGES_H_\n");
	fprintf(output_file, "#define WEBIF_PAGES_H_\n");
	fprintf(output_file, "\n");
	fprintf(output_file, "enum template_types {\n");
	fprintf(output_file, "	TEMPLATE_TYPE_TEXT = 0,\n");
	fprintf(output_file, "	TEMPLATE_TYPE_PNG  = 1,\n");
	fprintf(output_file, "	TEMPLATE_TYPE_GIF  = 2,\n");
	fprintf(output_file, "	TEMPLATE_TYPE_ICO  = 3,\n");
	fprintf(output_file, "	TEMPLATE_TYPE_JPG  = 4,\n");
	fprintf(output_file, "};\n");
	fprintf(output_file, "\n");
#ifdef USE_COMPRESSION
	fprintf(output_file, "#define COMPRESSED_TEMPLATES 1\n\n");
	fprintf(output_file, "struct template {\n");
	fprintf(output_file, "	uint32_t tpl_name_ofs;\n");
	fprintf(output_file, "	uint32_t tpl_data_ofs;\n");
	fprintf(output_file, "	uint32_t tpl_deps_ofs;\n");
	fprintf(output_file, "	uint32_t tpl_data_len;\n");
	fprintf(output_file, "	uint8_t tpl_type;\n");
	fprintf(output_file, "};\n");
#else
	fprintf(output_file, "struct template {\n");
	fprintf(output_file, "	char *tpl_name;\n");
	fprintf(output_file, "	char *tpl_data;\n");
	fprintf(output_file, "	char *tpl_deps;\n");
	fprintf(output_file, "	uint32_t tpl_data_len;\n");
	fprintf(output_file, "	uint8_t tpl_type;\n");
	fprintf(output_file, "};\n");
#endif
	fprintf(output_file, "\n");
	fprintf(output_file, "int32_t templates_count(void);\n");
	fprintf(output_file, "bool template_is_image(enum template_types tpl_type);\n");
	fprintf(output_file, "const char *template_get_mimetype(enum template_types tpl_type);\n");
	fprintf(output_file, "const struct template *templates_get(void);\n");
#ifdef USE_COMPRESSION
	fprintf(output_file, "void templates_get_data(const char **data, size_t *data_len, size_t *odata_len);\n");
#endif
	fprintf(output_file, "\n");
	fprintf(output_file, "#endif\n");
	fclose(output_file);

	output_file = xfopen(output_pages_c, "w");
	fprintf(output_file, "#include \"../globals.h\"\n");
	fprintf(output_file, "\n");
	fprintf(output_file, "#ifdef WEBIF\n");
	fprintf(output_file, "\n");
	fprintf(output_file, "#include \"pages.h\"\n");
	fprintf(output_file, "\n");

#ifdef USE_COMPRESSION
	// Calculate positions at which the values would be storred
	uint32_t cur_pos = 0;
#define align_up(val, align) (val += (align - val % align))
	for(i = 0; i < templates.num; i++)
	{
		struct template *t = &templates.data[i];
		readfile(t->file, &t->buf, &t->buf_len);
		t->data_len = t->buf_len;
		// +1 to leave space for \0
		t->ident_ofs = cur_pos;
		cur_pos += strlen(t->ident) + 1;
		align_up(cur_pos, sizeof(void *));
		t->data_ofs  = cur_pos;
		cur_pos += t->data_len      + 1;
		align_up(cur_pos, sizeof(void *));
		t->deps_ofs  = cur_pos;
		cur_pos += strlen(t->deps)  + 1;
		align_up(cur_pos, sizeof(void *));
	}

	// Allocate template data and populate it
#define data_len cur_pos
	if(!data_len)
		die("No defined templates");
	uint8_t *data = calloc(1, data_len);
	if(!data)
		{ die("Can't alloc %u bytes", data_len); }
	for(i = 0; i < templates.num; i++)
	{
		struct template *t = &templates.data[i];
		memcpy(data + t->ident_ofs, t->ident, strlen(t->ident));
		memcpy(data + t->data_ofs , t->buf  , t->buf_len);
		free(t->buf);
		if(!t->deps[0])  // No need to copy empty deps
			{ continue; }
		memcpy(data + t->deps_ofs, t->deps, strlen(t->deps));
	}
	FILE *bin = xfopen("pages.bin", "w");
	fwrite(data, data_len, 1, bin);
	fclose(bin);

	// Compress template data
	lzo_uint in_len  = data_len;
	lzo_uint out_len = data_len + data_len / 16 + 64 + 3; // Leave enough space in the output
	uint8_t *out = malloc(out_len);
	if(!out)
		{ die("Can't alloc %zu bytes", out_len); }

	if(lzo_init() != LZO_E_OK)
	{
		fprintf(stderr, "internal error - lzo_init() failed !!!\n");
		fprintf(stderr, "(this usually indicates a compiler bug - try recompiling\nwithout optimizations, and enable '-DLZO_DEBUG' for diagnostics)\n");
		free(out);
		free(data);
		return 3;
	}

	int r = lzo1x_1_compress(data, in_len, out, &out_len, wrkmem);
	if(r == LZO_E_OK)
	{
		int64_t saved_bytes = (int64_t)in_len - (int64_t)out_len;
		printf("GEN\tCompressed %lu template bytes into %lu bytes. %" PRId64 " saved bytes (%.2f%%).\n",
				(unsigned long)in_len, (unsigned long)out_len,
				saved_bytes, 100 - ((float)out_len / in_len) * 100);
	}
	else
	{
		/* this should NEVER happen */
		printf("internal error - compression failed: %d\n", r);
		free(out);
		free(data);
		return 2;
	}

	bin = xfopen("pages.bin.compressed", "w");
	fwrite(out, out_len, 1, bin);
	fclose(bin);

	dump_cbinary("templates_data", out, out_len, data_len);
	free(out);
	free(data);
#else
	for(i = 0; i < templates.num; i++)
	{
		uint8_t *buf;
		size_t buf_len;
		readfile(templates.data[i].file, &buf, &buf_len);
		templates.data[i].data_len = buf_len;
		switch(templates.data[i].type)
		{
		case TXT:
			dump_text(templates.data[i].ident, buf, buf_len);
			break;
		case BIN:
			dump_binary(templates.data[i].ident, buf, buf_len);
			break;
		}
		free(buf);
	}
#endif

	fprintf(output_file, "static const struct template templates[] = {\n");
	for(i = 0; i < templates.num; i++)
	{
		print_template(i);
	}
	fprintf(output_file, "};\n");
	fprintf(output_file, "\n");
	fprintf(output_file, "int32_t templates_count(void) { return sizeof(templates) / sizeof(struct template); }\n");
	fprintf(output_file, "const struct template *templates_get(void) { return templates; }\n");
#ifdef USE_COMPRESSION
	fprintf(output_file, "void templates_get_data(const char **data, size_t *data_len, size_t *data_olen) { *data = templates_data; *data_len = templates_data_len; *data_olen = templates_data_olen; }\n");
#endif
	fprintf(output_file, "\n");
	fprintf(output_file, "bool template_is_image(enum template_types tpl_type) {\n");
	fprintf(output_file, "	switch (tpl_type) {\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_PNG:\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_GIF:\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_ICO:\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_JPG:\n");
	fprintf(output_file, "		return true;\n");
	fprintf(output_file, "	default:\n");
	fprintf(output_file, "		return false;\n");
	fprintf(output_file, "	}\n");
	fprintf(output_file, "	return false;\n");
	fprintf(output_file, "}\n");
	fprintf(output_file, "\n");
	fprintf(output_file, "const char *template_get_mimetype(enum template_types tpl_type) {\n");
	fprintf(output_file, "	switch (tpl_type) {\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_TEXT: return \"text/plain\";\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_PNG : return \"image/png\";\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_GIF : return \"image/gif\";\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_ICO : return \"image/x-icon\";\n");
	fprintf(output_file, "	case TEMPLATE_TYPE_JPG : return \"image/jpg\";\n");
	fprintf(output_file, "	}\n");
	fprintf(output_file, "	return \"\";\n");
	fprintf(output_file, "}\n");
	fprintf(output_file, "\n");
	fprintf(output_file, "#endif\n");
	fclose(output_file);

	return 0;
}