/*
 * Conky, a system monitor, based on torsmo
 *
 * This program is licensed under BSD license, read COPYING
 *
 *  $Id$
 */

#include "top.h"

static regex_t *exclusion_expression = 0;
static unsigned long g_time = 0;
static unsigned long previous_total = 0;
static struct process *first_process = 0;

struct process *get_first_process()
{
	return first_process;
}

void free_all_processes(struct process *pr)
{
	struct process *next = NULL;
	while (pr) {
		next = pr->next;
		if (pr->name) {
			free(pr->name);
		}
		free(pr);
		pr = next;
	}
}

static struct process *find_process(pid_t pid)
{
	struct process *p = first_process;
	while (p) {
		if (p->pid == pid)
			return p;
		p = p->next;
	}
	return 0;
}

/*
* Create a new process object and insert it into the process list
*/
static struct process *new_process(int p)
{
	struct process *process;
	process = (struct process*)malloc(sizeof(struct process));

	// clean up memory first
	memset(process, 0, sizeof(struct process));

	/*
	 * Do stitching necessary for doubly linked list
	 */
	process->name = 0;
	process->previous = 0;
	process->next = first_process;
	if (process->next)
		process->next->previous = process;
	first_process = process;

	process->pid = p;
	process->time_stamp = 0;
	process->previous_user_time = ULONG_MAX;
	process->previous_kernel_time = ULONG_MAX;
	process->counted = 1;

	
	/*    process_find_name(process); */

	return process;
}

/******************************************/
/* Functions                              */
/******************************************/

static int process_parse_stat(struct process *);
static int update_process_table(void);
static int calculate_cpu(struct process *);
static void process_cleanup(void);
static void delete_process(struct process *);
/*inline void draw_processes(void);*/
static unsigned long calc_cpu_total(void);
static void calc_cpu_each(unsigned long);


/******************************************/
/* Extract information from /proc         */
/******************************************/

/*
* These are the guts that extract information out of /proc.
* Anyone hoping to port wmtop should look here first.
*/
static int process_parse_stat(struct process *process)
{
	struct information *cur;
	cur = &info;
	char line[BUFFER_LEN], filename[BUFFER_LEN], procname[BUFFER_LEN];
	int ps;
	unsigned long user_time = 0;
	unsigned long kernel_time = 0;
	int rc;
	char *r, *q;
	char deparenthesised_name[BUFFER_LEN];
	int endl;
	int nice_val;

	snprintf(filename, sizeof(filename), PROCFS_TEMPLATE,
		 process->pid);

	ps = open(filename, O_RDONLY);
	if (ps < 0)
		/*
		 * The process must have finished in the last few jiffies!
		 */
		return 1;

	/*
	 * Mark process as up-to-date.
	 */
	process->time_stamp = g_time;

	rc = read(ps, line, sizeof(line));
	close(ps);
	if (rc < 0)
		return 1;

	/*
	 * Extract cpu times from data in /proc filesystem
	 */
	rc = sscanf(line,
		    "%*s %s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %lu %lu %*s %*s %*s %d %*s %*s %*s %d %d",
		    procname, &process->user_time, &process->kernel_time,
		    &nice_val, &process->vsize, &process->rss);
	if (rc < 5)
		return 1;
	/*
	 * Remove parentheses from the process name stored in /proc/ under Linux...
	 */
	r = procname + 1;
	/* remove any "kdeinit: " */
	if (r == strstr(r, "kdeinit")) {
		snprintf(filename, sizeof(filename),
			 PROCFS_CMDLINE_TEMPLATE, process->pid);

		ps = open(filename, O_RDONLY);
		if (ps < 0)
			/*
			 * The process must have finished in the last few jiffies!
			 */
			return 1;

		endl = read(ps, line, sizeof(line));
		close(ps);

		/* null terminate the input */
		line[endl] = 0;
		/* account for "kdeinit: " */
		if ((char *) line == strstr(line, "kdeinit: "))
			r = ((char *) line) + 9;
		else
			r = (char *) line;

		q = deparenthesised_name;
		/* stop at space */
		while (*r && *r != ' ')
			*q++ = *r++;
		*q = 0;
	} else {
		q = deparenthesised_name;
		while (*r && *r != ')')
			*q++ = *r++;
		*q = 0;
	}

	if (process->name) {
		free(process->name);
	}
	process->name = strdup(deparenthesised_name);
	process->rss *= getpagesize();

	if (!cur->memmax)
		update_total_processes();



	process->totalmem = (float)(((float) process->rss / cur->memmax) / 10);
	if (process->previous_user_time == ULONG_MAX)
		process->previous_user_time = process->user_time;
	if (process->previous_kernel_time == ULONG_MAX)
		process->previous_kernel_time = process->kernel_time;

	/* store the difference of the user_time */
	user_time = process->user_time - process->previous_user_time;
	kernel_time = process->kernel_time - process->previous_kernel_time;

	/* backup the process->user_time for next time around */
	process->previous_user_time = process->user_time;
	process->previous_kernel_time = process->kernel_time;

	/* store only the difference of the user_time here... */
	process->user_time = user_time;
	process->kernel_time = kernel_time;


	return 0;
}

/******************************************/
/* Update process table                   */
/******************************************/

static int update_process_table()
{
	DIR *dir;
	struct dirent *entry;

	if (!(dir = opendir("/proc")))
		return 1;

	++g_time;

	/*
	 * Get list of processes from /proc directory
	 */
	while ((entry = readdir(dir))) {
		pid_t pid;

		if (!entry) {
			/*
			 * Problem reading list of processes
			 */
			closedir(dir);
			return 1;
		}

		if (sscanf(entry->d_name, "%d", &pid) > 0) {
			struct process *p;
			p = find_process(pid);
			if (!p)
				p = new_process(pid);

			/* compute each process cpu usage */
			calculate_cpu(p);
		}
	}

	closedir(dir);

	return 0;
}

/******************************************/
/* Get process structure for process pid  */
/******************************************/

/*
* This function seems to hog all of the CPU time. I can't figure out why - it
* doesn't do much.
*/
static int calculate_cpu(struct process *process)
{
	int rc;

	/* compute each process cpu usage by reading /proc/<proc#>/stat */
	rc = process_parse_stat(process);
	if (rc)
		return 1;
	/*rc = process_parse_statm(process);
	   if (rc)
	   return 1; */

	/*
	 * Check name against the exclusion list
	 */
	if (process->counted && exclusion_expression
	    && !regexec(exclusion_expression, process->name, 0, 0, 0))
		process->counted = 0;

	return 0;
}

/******************************************/
/* Strip dead process entries             */
/******************************************/

static void process_cleanup()
{

	struct process *p = first_process;
	while (p) {
		struct process *current = p;

#if defined(PARANOID)
		assert(p->id == 0x0badfeed);
#endif				/* defined(PARANOID) */

		p = p->next;
		/*
		 * Delete processes that have died
		 */
		if (current->time_stamp != g_time)
			delete_process(current);
	}
}

/******************************************/
/* Destroy and remove a process           */
/******************************************/

static void delete_process(struct process *p)
{
#if defined(PARANOID)
	assert(p->id == 0x0badfeed);

	/*
	 * Ensure that deleted processes aren't reused.
	 */
	p->id = 0x007babe;
#endif				/* defined(PARANOID) */

	/*
	 * Maintain doubly linked list.
	 */
	if (p->next)
		p->next->previous = p->previous;
	if (p->previous)
		p->previous->next = p->next;
	else
		first_process = p->next;

	if (p->name) {
		free(p->name);
	}
	free(p);
}

/******************************************/
/* Calculate cpu total                    */
/******************************************/

static unsigned long calc_cpu_total()
{
	unsigned long total = 0;
	unsigned long t = 0;
	int rc;
	int ps;
	char line[BUFFER_LEN];
	unsigned long cpu = 0;
	unsigned long nice = 0;
	unsigned long system = 0;
	unsigned long idle = 0;

	ps = open("/proc/stat", O_RDONLY);
	rc = read(ps, line, sizeof(line));
	close(ps);
	if (rc < 0)
		return 0;
	sscanf(line, "%*s %lu %lu %lu %lu", &cpu, &nice, &system, &idle);
	total = cpu + nice + system + idle;

	t = total - previous_total;
	previous_total = total;


	return t;
}

/******************************************/
/* Calculate each processes cpu           */
/******************************************/

inline static void calc_cpu_each(unsigned long total)
{
	struct process *p = first_process;
	while (p) {
		/*p->amount = total ?
		   (100.0 * (float) (p->user_time + p->kernel_time) /
		   total) : 0; */
		p->amount =
		    (100.0 * (p->user_time + p->kernel_time) / total);

/*		if (p->amount > 100)
		p->amount = 0;*/
		p = p->next;
	}
}

/******************************************/
/* Find the top processes                 */
/******************************************/


/*
 * cpu comparison function for insert_sp_element 
 */
int compare_cpu(struct process *a, struct process *b) {
	if (a->amount < b->amount) return 1; 
	return 0;
}

/*
 * mem comparison function for insert_sp_element 
 */
int compare_mem(struct process *a, struct process *b) {
	if (a->totalmem < b->totalmem) return 1; 
	return 0;
}

/*
 * insert this process into the list in a sorted fashion,
 * or destroy it if it doesn't fit on the list
*/ 
int insert_sp_element(
                     struct sorted_process * sp_cur
                   , struct sorted_process ** p_sp_head
                   , struct sorted_process ** p_sp_tail
		   , int max_elements
                   , int (*compare_funct) (struct process *, struct process *)
		  ) {

	struct sorted_process * sp_readthru=NULL, * sp_destroy=NULL;
	int did_insert = 0, x = 0;

	if (*p_sp_head == NULL) {
		*p_sp_head = sp_cur;
		*p_sp_tail = sp_cur;
		return(1);
	}
	for(sp_readthru=*p_sp_head, x=0; sp_readthru != NULL && x < max_elements; sp_readthru=sp_readthru->less, x++) {
		if (compare_funct(sp_readthru->proc, sp_cur->proc) && !did_insert) {
			/* sp_cur is bigger than sp_readthru so insert it before sp_readthru */
			sp_cur->less=sp_readthru;
			if (sp_readthru == *p_sp_head) { 
				*p_sp_head = sp_cur;  /* insert as the new head of the list */
			} else {
				sp_readthru->greater->less = sp_cur;  /* insert inside  the list */
				sp_cur->greater = sp_readthru->greater; 
			}
			sp_readthru->greater=sp_cur;
			did_insert = ++x;  /* element was inserted, so increase the counter */
		}
	}
	if (x < max_elements && sp_readthru == NULL && !did_insert) {
		/* sp_cur is the smallest element and list isn't full, so insert at the end */  
		(*p_sp_tail)->less=sp_cur;
		sp_cur->greater=*p_sp_tail;
		*p_sp_tail = sp_cur;
		did_insert=x;
	} else if (x == max_elements && sp_readthru != NULL) {
		/* we inserted an element and now the list is too big by one. Destroy the smallest element */
		sp_destroy = sp_readthru;
		sp_readthru->greater->less = NULL;
		*p_sp_tail = sp_readthru->greater;
		free(sp_destroy);
	}
	if (!did_insert) {
		/* sp_cur wasn't added to the sorted list, so destroy it */
		free(sp_cur);
	}
	return did_insert;
}

/*
 * create a new sp_process structure
*/
struct sorted_process * malloc_sp(struct process * proc) {
	struct sorted_process * sp;
	sp = malloc(sizeof(struct sorted_process));
	sp->greater = NULL;
	sp->less = NULL;
	sp->proc = proc;
	return(sp);
} 
  
/*
 * copy the procs in the sorted list to the array, and destroy the list 
 */
void sp_acopy(struct sorted_process *sp_head, struct process ** ar, int max_size)
{
	struct sorted_process * sp_cur, * sp_tmp;
	int x;
	sp_cur = sp_head;
	for (x = 0; x < max_size && sp_cur != NULL; x++) {
		ar[x] = sp_cur->proc;	
		sp_tmp = sp_cur;
		sp_cur = sp_cur->less;
		free(sp_tmp);
	}
}

// stole from common.c
#define NEED(a) ((need_mask & (1 << a)) && ((info.mask & (1 << a)) == 0))

/* ****************************************************************** */
/* Get a sorted list of the top cpu hogs and top mem hogs.            */
/* Results are stored in the cpu,mem arrays in decreasing order[0-9]. */
/* ****************************************************************** */

inline void process_find_top(struct process **cpu, struct process **mem)
{
	struct sorted_process *spc_head = NULL, *spc_tail = NULL, *spc_cur = NULL;
	struct sorted_process *spm_head = NULL, *spm_tail = NULL, *spm_cur = NULL;
	struct process *cur_proc = NULL;
	unsigned long total = 0;

	if (!top_cpu && !top_mem) return;

	total = calc_cpu_total();	/* calculate the total of the processor */
	update_process_table();	        /* update the table with process list */
	calc_cpu_each(total);	        /* and then the percentage for each task */
	process_cleanup();	        /* cleanup list from exited processes */
	
	cur_proc = first_process;

	while (cur_proc !=NULL) {
		if (top_cpu) {
			spc_cur = malloc_sp(cur_proc);
			insert_sp_element(spc_cur, &spc_head, &spc_tail, MAX_SP, &compare_cpu);
		}
		if (top_mem) {
			spm_cur = malloc_sp(cur_proc);
			insert_sp_element(spm_cur, &spm_head, &spm_tail, MAX_SP, &compare_mem);
		}
		cur_proc = cur_proc->next;
	}
	sp_acopy(spc_head, cpu, MAX_SP);
	sp_acopy(spm_head, mem, MAX_SP);
}