/*
 * main.c: the daemon itself
 */

#include <unistd.h>
#include <syslog.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <signal.h>

#include "config.h"
#include "trie.h"
#include "task.h"
#include "daemonize.h"
#include "async.h"

enum resp {
	SUCCESS, FAIL
};

void reg_sig_handlers(void);
bool process(int fd);

int sockfd; //async.h has to be able to use it, and I would hate to write a getter for that

int main (void) {
	openlog(cfg_log_ident, cfg_log_opt, cfg_log_facility); //I will probably close its fd a moment later, FIXME
	syslog(cfg_log_facility | LOG_INFO, "Starting");
	// No arguments, if you want something, go change source, according to documentation.
//	daemonize(0);

	// Load saved state -- variable values and tasks
	async_load(0);

	// Set basic signal handlers
	reg_sig_handlers();

	// Setup a socket to listen on
	sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
	struct sockaddr_un addr;
	socklen_t addrsize = sizeof(struct sockaddr_un);
	addr.sun_family = AF_UNIX;
	memcpy(&addr.sun_path, cfg_socket, strlen(cfg_socket)+1);
	if(bind(sockfd, (struct sockaddr *) &addr, sizeof(struct sockaddr_un)) == -1) {
		syslog(cfg_log_facility | LOG_ERR, "daemon: bind failed: %m");
	}
	if(listen(sockfd, cfg_sock_maxclients) == -1) {
		syslog(cfg_log_facility | LOG_ERR, "daemon: listen failed: %m");
	}

	// Everything prepared
	syslog(cfg_log_facility | LOG_INFO, "Started");

	// Main loop: (everything else is handled by process() and signal handlers).
	while (true) {
		int fd = accept(sockfd, (struct sockaddr *) &addr, &addrsize);
		if (fd == -1) {
			syslog(cfg_log_facility | LOG_ERR, "daemon: accept failed: %m");
			while(1);
			break;
		} else {
			syslog(cfg_log_facility | LOG_INFO, "daemon: accepted new connection");
			process(fd);
		}
	}

	syslog(cfg_log_facility | LOG_CRIT, "Escaped infinite loop!");
	return 5;
}

uint64_t read_uint64(int fd) {
	char buf[8];
	read(fd, buf, 8);
	uint64_t num = *(uint64_t *)buf;
	return num;
}

bool write_uint64(uint64_t num, int fd) {
	char *buf = &num;
	write(fd, buf, 8);
	return true; //TODO: error handling
}

char *read_string(int fd) {
	char *buf;
	struct grow *tmp = grow_init(true);
	do {
		buf = malloc(1);
		if(buf == NULL) {
			syslog(cfg_log_facility | LOG_ERR, "cannot malloc memory for a letter: %m");
			grow_drop(tmp);
			return NULL;
		}
		read(fd, buf, 1);
		grow_push(buf, tmp);
	} while (buf[0] != '\0');
	char *str = malloc(tmp->elems * sizeof(char));
	if (str == NULL) {
		syslog(cfg_log_facility | LOG_ERR, "cannot malloc memory for string: %m");
		grow_drop(tmp);
		return NULL;
	}
	for (uint64_t j = 0; j < tmp -> elems; j++) {
		str[j] = *(char *)(tmp->arr[j]);
	}
	grow_drop(tmp);
	syslog(cfg_log_facility | LOG_DEBUG, "daemon: read_string: returning '%s'", str);
	return str;
}

bool write_string (char *str, int fd) {
	int len = strlen(str)+1;
	write(fd, str, len);
	return true; // TODO: error handling
}

void response(enum resp r, int fd) {
	if (r==SUCCESS) {
		char str[] = "OK";
		write(fd, str, 2);
	} else {
		char str[] = "KO";
		write(fd, str, 2);
	}
	return;
}

bool process(int fd) {
	char cmd[5];
	read(fd, cmd, 4);
	cmd[4] = '\0';
	if (0){ //alignment
		return true;
	} else if (strcmp(cmd, "TADD") == 0) {
		struct task *t = task_read(fd);
		if (t == NULL) {			// We do not handle errors here, they are already logged
			response(FAIL,fd);
			return false;
		}
		if(task_add(*t)) {
			response(SUCCESS,fd);
			return true;
		} else {
			response(FAIL,fd);
			return false;
		}
	} else if (strcmp(cmd, "TDEL") == 0) {
		uint64_t id = read_uint64(fd);
		if(task_delete(id)) {
			response(SUCCESS,fd);
			return true;
		} else {
			response(FAIL,fd);
			return false;
		}
	} else if (strcmp(cmd, "TENA") == 0) {
		uint64_t id = read_uint64(fd);
		if(task_enable(id)) {
			response(SUCCESS,fd);
			return true;
		} else {
			response(FAIL,fd);
			return false;
		}
	} else if (strcmp(cmd, "TDIS") == 0) {
		uint64_t id = read_uint64(fd);
		if(task_disable(id)) {
			response(SUCCESS,fd);
			return true;
		} else {
			response(FAIL,fd);
			return false;
		}
	} else if (strcmp(cmd, "TDET") == 0) {
		uint64_t id = read_uint64(fd);
		struct task t = task_details(id);
		response(SUCCESS, fd);
		return task_write(t, fd);
	} else if (strcmp(cmd, "TLST") == 0) {
		bool retval = true;
		struct grow *lst = task_list();
		if (lst == NULL) {
			response(SUCCESS, fd);
			retval &= write_uint64(0, fd);
		} else {
			response(SUCCESS,fd);
			retval &= write_uint64(lst->active_elems, fd);
			for (uint64_t i = 0; i < lst->elems; i++) {
				if (lst->arr[i] == NULL) {
					continue;
				} else {
					struct task t = *(struct task *)lst->arr[i];
					retval &= task_write(t, fd);
				}
			}
		}
		return retval;

	} else if (strcmp(cmd, "VADD") == 0) {
		int64_t val = (int64_t) read_uint64(fd);
		char *str = read_string(fd);
		if(trie_set(str, val)) {
			response(SUCCESS, fd);
			return true;
		} else {
			response(FAIL, fd);
			return false;
		}
	} else if (strcmp(cmd, "VSET") == 0) {
		int64_t val = (int64_t) read_uint64(fd);
		char *str = read_string(fd);
		if(trie_set(str, val)) {
			response(SUCCESS, fd);
			return true;
		} else {
			response(FAIL, fd);
			return false;
		}
	} else if (strcmp(cmd, "VDEL") == 0) {
		char *str = read_string(fd);
		if(trie_unset(str)) {
			response(SUCCESS, fd);
			return true;
		} else {
			response(FAIL, fd);
			return false;
		}
	} else if (strcmp(cmd, "VLST") == 0) {
		bool retval = true;
		struct grow *lst = trie_list();
		if (lst == NULL) {
			response(SUCCESS, fd);
			retval &= write_uint64(0, fd);
			return retval;
		}
		response(SUCCESS, fd);
		retval &= write_uint64(lst->elems, fd);
		for (uint64_t i = 0; i < lst->elems; i++) {
			struct trie_list item = *(struct trie_list *)lst->arr[i];
			retval &= write_uint64(item.val, fd);
			retval &= write_string(item.name, fd);
		}
		return retval;
	} else if (strcmp(cmd, "VDET") == 0) {
		char *name = read_string(fd);
		if (name == NULL) {
			response(FAIL, fd);
			return false;
		}
		struct trie_retval var = trie_lookup(name);
		response(SUCCESS, fd);
		write(fd, &var, sizeof(struct trie_retval));
		if (var.tasks == NULL) {
			write_uint64(0, fd);
			return true;
		}
		write_uint64(var.tasks->active_elems, fd);
		for(uint64_t i = 0; i< var.tasks->elems; i++) {
			if(var.tasks->arr[i] == NULL) {
				continue;
			} else {
				uint64_t task = *(uint64_t *)var.tasks->arr[i];
				write_uint64(task, fd);
			}
		}
		return true; // TODO: error handling!!

	} else if (strcmp(cmd, "QUIT") == 0) {
		response(SUCCESS, fd);
		async_shutdown(0);
		return true;
	} else if (strcmp(cmd, "REST") == 0) {
		response(SUCCESS, fd);
		async_restart(0);
		return true;
	} else if (strcmp(cmd, "SAVE") == 0) {
		response(SUCCESS, fd);
		async_save(0);
		return true;
	} else if (strcmp(cmd, "FLSH") == 0) {
		char *safe = calloc(1+strlen(cfg_safe_string), sizeof(char));
		read(fd, safe, strlen(cfg_safe_string));
		if (strcmp(safe, cfg_safe_string) == 0) {
			response(SUCCESS, fd);
			async_flush(0);
			return true;
		} else {
			response(FAIL, fd);
			return false;
		}
	} else if (strcmp(cmd, "LOAD") == 0) {
		char *safe = calloc(1+strlen(cfg_safe_string), sizeof(char));
		read(fd, safe, strlen(cfg_safe_string));
		if (strcmp(safe, cfg_safe_string) == 0) {
			response(SUCCESS, fd);
			async_load(0);
			return true;
		} else {
			response(FAIL, fd);
			return false;
		}
	} else if (strcmp(cmd, "KILL") == 0) {
		char *safe = calloc(1+strlen(cfg_safe_string), sizeof(char));
		read(fd, safe, strlen(cfg_safe_string));
		if (strcmp(safe, cfg_safe_string) == 0) {
			response(SUCCESS, fd);
			async_kill(0);
			return true;
		} else {
			response(FAIL, fd);
			return false;
		}

	} else {
		syslog(cfg_log_facility | LOG_NOTICE, "Unknown command: %s (0x%02X%02X%02X%02X)", cmd, cmd[0], cmd[1], cmd[2], cmd[3]);
		char str[] = "KO";
		write(fd, str, 2);
		response(FAIL,fd);
		return false;
	}
}


void reg_sig_handlers(void) {
	sigset_t empty;
	sigemptyset(&empty); // Shall not fail

	//SIGTERM
	struct sigaction term_sigh;
	term_sigh.sa_handler = &async_shutdown;
	term_sigh.sa_mask = empty;
	term_sigh.sa_flags = 0;
	sigaction(SIGTERM, &term_sigh, NULL);

	//SIGCHLD
	struct sigaction chld_sigh;
	chld_sigh.sa_handler = SIG_IGN; // We don't care for children
	chld_sigh.sa_mask = empty;
	chld_sigh.sa_flags = SA_NOCLDWAIT;
	sigaction(SIGCHLD, &chld_sigh, NULL);

	//SIGHUP
	struct sigaction hup_sigh;
	hup_sigh.sa_handler = &async_restart;
	hup_sigh.sa_mask = empty;
	hup_sigh.sa_flags = 0;
	sigaction(SIGHUP, &hup_sigh, NULL);

	//SIGINT
	struct sigaction int_sigh;
	int_sigh.sa_handler = &async_save;
	int_sigh.sa_mask = empty;
	int_sigh.sa_flags = 0;
	sigaction(SIGINT, &int_sigh, NULL);

	//SIGALRM
	struct sigaction alrm_sigh;
	alrm_sigh.sa_sigaction = &async_run;
	alrm_sigh.sa_mask = empty;
	alrm_sigh.sa_flags = SA_SIGINFO;
	sigaction(SIGALRM, &alrm_sigh, NULL);
}