/**
	rexbacklight
	Copyright (C) 2018 rexy712

	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 <stdio.h> //printf
#include <string.h> //strcmp, strlen
#include <rjp.h>
#include <sys/types.h> //getpwnam
#include <pwd.h> //getpwnam
#include <unistd.h> //chdir
#include <stdlib.h> //malloc, free

#include "restore.h"
#include "common.h"
#include "cmd.h"
#include "globals.h"
#include "rexbacklight.h"

static char* get_home_folder(void){
	char* user = getenv("SUDO_USER");
	char* home = getenv("HOME");
	if(!home || user){
		if(!user){
			return NULL;
		}
		struct passwd* pw_entry = getpwnam(user);
		if(!pw_entry){
			return NULL;
		}
		home = pw_entry->pw_dir;
	}
	return home;
}
static char* restore_file(void){
	char* home_folder = get_home_folder();
	if(!home_folder)
		return NULL;

	//"/.config/rexbacklight.json"
	size_t home_folder_len = strlen(home_folder);
	size_t conf_len = strlen(restore_file_suffix());
	char* rest_file = malloc(home_folder_len + conf_len + 1);
	strncpy(rest_file, home_folder, home_folder_len);
	strncpy(rest_file+home_folder_len, restore_file_suffix(), conf_len);
	rest_file[home_folder_len+conf_len] = 0;
	return rest_file;
}

RJP_value* read_restore_file(const char* file){
	size_t filesize;
	char* file_contents;
	int i;
	FILE* fp = fopen(file, "r");
	if(!fp){
		fprintf(stderr, "Could not restore! No restore file found!\n");
		return NULL;
	}

	fseek(fp, 0, SEEK_END);
	filesize = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	file_contents = malloc(filesize+1);
	i = fread(file_contents, filesize, 1, fp);
	fclose(fp);
	file_contents[filesize] = 0;
	RJP_value* root = rjp_parse(file_contents);
	free(file_contents);
	return root;
}

RJP_value* find_matching_json_device(const char* name, RJP_value* root){
	for(RJP_value* curr = rjp_get_member(root);curr;curr = rjp_next_member(curr)){
		if(!strcmp(rjp_member_name(curr), name)){
			return curr;
		}
	}
	return NULL;
}

//convert a restoration operation to a set operation
int restore_to_delta(struct arg_values* curr, RJP_value** root, int* try_restore){
	if(!*root && *try_restore){
		char* tmp = restore_file();
		*root = read_restore_file(tmp);
		free(tmp);
		if(!*root){
			*try_restore = 0;
			return 0;
		}
	}
	RJP_value* match = find_matching_json_device(curr->device, *root);
	if(!match){
		fprintf(stderr, "No matching device '%s' in restore file!\n", curr->device);
		return 0;
	}
	curr->operation = OP_SET;
	curr->delta = rjp_value_dfloat(match);
	return 1;
}

void save_restore_file(struct string_array* devices){
 	RJP_value* root = rjp_init_json();
	for(size_t i = 0;i < devices->size;++i){
		if(chdir(devices->list[i])){
			io_error_2(IO_ERROR_OPEN, IO_ERROR_DIR, device_dir(), devices->list[i]);
			return_value = RETVAL_INVALID_DIR;
			continue;
		}
		size_t esc_name_len = rjp_escape_strlen(devices->list[i]);
		char* esc_str = rjp_alloc(esc_name_len + 1);
		rjp_escape_strcpy(esc_str, devices->list[i]);

		float curr = get_brightness(brightness_file());
		float max = get_brightness(max_brightness_file());
		if(return_value == RETVAL_INVALID_FILE && (!curr || !max)){
			rjp_add_member(root, 0, esc_str, 0, rjp_null());
		}else{
			rjp_add_member(root, 0, esc_str, 0, rjp_dfloat(curr/max*100));
		}

		if(chdir(device_dir())){
			io_error(IO_ERROR_OPEN, IO_ERROR_DIR, device_dir());
			return_value = RETVAL_INVALID_DIR;
			rjp_free_value(root);
			free(esc_str);
			return;
		}
	}
	char* tmp = rjp_to_json(root);
	char* rfil = restore_file();
	FILE* restf = fopen(rfil, "w");
	if(!restf){
		io_error(IO_ERROR_OPEN, IO_ERROR_FILE, rfil);
	}else{
		fprintf(restf, "//File generated by %s\n%s\n", executable_name(), tmp);
		fclose(restf);
	}
	free(rfil);
	rjp_free(tmp);
	rjp_free_value(root);
}