#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <errno.h>
#include <pwd.h>
#include <time.h>
#include <limits.h>
#include "proc_parser.h"
#include "human.h"

static char c_flag;

static int pscan(const pid_t pid, const char *prog_name) {
	struct mu_proc proc;
	if (mu_proc_parser("ps", pid, &proc))
		return 1;

	if (prog_name != NULL && strncmp(proc.cmd, prog_name, strlen(prog_name)))
		return 1;

	/* Uid */
	char *name = "unknow";
	struct passwd *pw = getpwuid(proc.uid);
	if (pw != NULL)
		name = pw->pw_name;

	/* Time */
	unsigned int rtime = (proc.utime + proc.stime) / sysconf(_SC_CLK_TCK);

	/* Print */
	char virt[MU_HUMAN_BUF_SIZE + 1];
	strcpy(virt, mu_humansize(proc.vsize, 1024));

	char rss[MU_HUMAN_BUF_SIZE + 1];
	strcpy(rss, mu_humansize(proc.vmrss * 1024, 1024));

	char *prog = (c_flag) ? proc.cmdline : proc.cmd;
	if (prog[0] == '\0')
		return 0;

	printf("%6d %8s %4ld %4ld %8s %8s %2c %02um:%02us %2s\n", proc.pid, name, proc.priority, proc.nice, virt, rss, proc.state, rtime / 60, rtime % 60, prog);
	return 0;
}

static char name_2_pid(const char *prog_name) {
	DIR *dp = opendir("/proc");
	if (dp == NULL) {
		fprintf(stderr, "ps: /proc: %s\n", strerror(errno));
		return 1;
	}

	int ret = 0;
	struct dirent *ep;
	while ((ep = readdir(dp)) != NULL) {
		pid_t pid = strtoul(ep->d_name, 0L, 10);
		if (pid)
			if (pscan(pid, prog_name))
				ret = 1;
	}

	closedir(dp);
	return ret;
}

int main(int argc, char **argv) {
	int opt;
	while ((opt = getopt(argc, argv, "c")) != -1) {
		switch (opt) {
			case 'c':
				c_flag = 1;
				break;

			default:
				puts("ps [c] [PID]\n\t-c Print cmdline instead of program name\n");
				return 0;
		}
	}

	argv += optind;
	argc -= optind;

	puts("   PID     USER  PRI NICE     VIRT      RSS  S RTIME   CMD");
	if (argc == 0)
		return name_2_pid(NULL);

	else {
		int ret = 0;
		for (int i = 0; i < argc; i++) {
			pid_t pid = strtoul(argv[i], 0L, 10);
			if (pid) {
				if (pscan(pid, NULL))
					ret = 1;
			}

			else
				if (name_2_pid(argv[i]))
					ret = 1;
		}

		return ret;
	}
}