#include "stat.h"

#include <ncurses.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/statvfs.h>
#include <unistd.h>

#include "display.h"
#include "err.h"
#include "log.h"
#include "mem.h"

stat *stat_init()
{
	stat *s = xmalloc(sizeof(stat));
	*s = (stat){
	    .sysver = "",
	    .meminfo = {.mem_available = 0, .mem_total = 0},
	    .diskinfo = {.disk_available = 0, .disk_total = 0},
	};
	s->cpu_occ = xmalloc(sizeof(cpu_occupy));

	if (s->cpu_occ)
		*s->cpu_occ = (cpu_occupy){0};
	return s;
}

void stat_get_sysver(stat *s)
{
	FILE *fp = fopen(PROC_PATH_VERSION, "r");
	if (!fp)
		die("Cannot open %s", PROC_PATH_VERSION);

	if (fgets(s->sysver, sizeof(s->sysver), fp) != NULL) {
		s->sysver[strcspn(s->sysver, "\n")] = '\0';
	}
	fclose(fp);
}
void stat_print_cpu_info(WINDOW *w, int y, int maxx, stat *s)
{
	mvwprintw(w, y, maxx - STAT_INFO_WIDTH, " %.2f %%",
		  s->cpu_occ->smooth_cpu);
}
void stat_print_info(WINDOW *w, int y, int maxx, const char *label,
		     unsigned long total, unsigned long ava)
{
	unsigned long long t_bytes = total;
	unsigned long long a_bytes = ava;

	if (strcmp(label, "Mem") == 0 || strcmp(label, "Mem ") == 0) {
		t_bytes *= 1024;
		a_bytes *= 1024;
	}

	const char *units[] = {"B", "K", "M", "G", "T"};

	int t_idx = 0;
	int a_idx = 0;

	double d_total = (double)t_bytes;
	double d_ava = (double)a_bytes;

	while (d_total >= 1024.0 && t_idx < 4) {
		d_total /= 1024.0;
		t_idx++;
	}

	while (d_ava >= 1024.0 && a_idx < 4) {
		d_ava /= 1024.0;
		a_idx++;
	}

	int startx = maxx - STAT_INFO_WIDTH;

	mvwprintw(w, y, startx, " %.2f%s/%.2f%s", d_ava, units[t_idx], d_total,
		  units[t_idx]);

	/* wrefresh(w); */
}

int stat_get_bar_ticks(int maxx, unsigned long long total,
		       unsigned long long ava)
{
	if (total == 0)
		return 0;
	if (ava >= total)
		return 0;

	unsigned long long used = total - ava;

	unsigned long long slots = (unsigned long long)(maxx);

	return (int)((slots * used) / total);
}

void stat_draw_cpu_bar(WINDOW *w, int maxx, int y, int x, stat *s)
{
	int ava_to_draw_x = maxx - STAT_INFO_WIDTH - BAR_LABEL_WIDTH;
	int total_hashes = ava_to_draw_x * (s->cpu_occ->smooth_cpu * 0.1);

	char hashes[2048] = {0};

	if (total_hashes > ava_to_draw_x)
		total_hashes = ava_to_draw_x;
	memset(hashes, '#', total_hashes);
	hashes[total_hashes] = '\0';

	mvwprintw(w, y, x, "%-*s [", 4, "CPU");
	wprintw_colorful(w, COLOR_PAIR_PROGRESS, "%.*s", total_hashes, hashes);

	int remaining_spaces = ava_to_draw_x - total_hashes;
	if (remaining_spaces > 0) {
		wprintw(w, "%*s", remaining_spaces, "");
	}

	waddch(w, ']');
}

void stat_draw_bar(WINDOW *w, const char *label, int maxx, int y, int x,
		   unsigned long total, unsigned long ava)
{
	int ava_to_draw_x = maxx - STAT_INFO_WIDTH - BAR_LABEL_WIDTH;
	int total_hashes = stat_get_bar_ticks(ava_to_draw_x, total, ava);
	char hashes[2048] = {0};

	init_pair(COLOR_PAIR_PROGRESS, COLOR_GREEN, COLOR_BLACK);

	if (total_hashes > ava_to_draw_x)
		total_hashes = ava_to_draw_x;
	memset(hashes, '#', total_hashes);
	hashes[total_hashes] = '\0';

	mvwprintw(w, y, x, "%-*s [", 4, label);
	wprintw_colorful(w, COLOR_PAIR_PROGRESS, "%.*s", total_hashes, hashes);

	int remaining_spaces = ava_to_draw_x - total_hashes;
	if (remaining_spaces > 0) {
		wprintw(w, "%*s", remaining_spaces, "");
	}

	waddch(w, ']');

	/* wrefresh(w); */
}

void stat_get_meminfo(stat *s)
{
	static char buf[128];
	char key[32] = "";
	unsigned long long val = 0;

	FILE *fp = fopen(PROC_PATH_MEMINFO, "r");
	if (!fp)
		die("Cannot open %s", PROC_PATH_MEMINFO);

	while (fgets(buf, sizeof(buf), fp)) {
		if (sscanf(buf, "%31[^:]: %llu", key, &val) == 2) {
			if (strcmp(key, "MemTotal") == 0) {
				s->meminfo.mem_total = val;
			} else if (strcmp(key, "MemAvailable") == 0) {
				s->meminfo.mem_available = val;
				break;
			}
		}
	}

	fclose(fp);
}

void stat_get_diskinfo(stat *s)
{
	struct statvfs vfs;
	if (statvfs("/", &vfs) != 0) {
		s->diskinfo.disk_total = 0;
		s->diskinfo.disk_available = 0;
		log_write(LOG_WARN, "Cannot get disk info");
	}

	s->diskinfo.disk_total =
	    (unsigned long long)vfs.f_blocks * vfs.f_frsize;
	s->diskinfo.disk_available =
	    (unsigned long long)vfs.f_bavail * vfs.f_frsize;
}

void stat_get_cpuinfo(stat *s)
{
	char buf[256];
	FILE *fp = fopen(PROC_PATH_STAT, "r");
	if (!fp) {
		log_write(LOG_WARN, "Cannot open %s", PROC_PATH_STAT);
		return;
	}

	if (!fgets(buf, sizeof(buf), fp)) {
		fclose(fp);
		return;
	}
	fclose(fp);

	unsigned long long user = 0, nice = 0, system = 0, idle = 0;
	unsigned long long iowait = 0, irq = 0, softirq = 0;

	sscanf(buf, "%*s %llu %llu %llu %llu %llu %llu %llu", &user, &nice,
	       &system, &idle, &iowait, &irq, &softirq);

	s->cpu_occ->user = user;
	s->cpu_occ->nice = nice;
	s->cpu_occ->system = system;
	s->cpu_occ->idle = idle;
	s->cpu_occ->iowait = iowait;
	s->cpu_occ->irq = irq;
	s->cpu_occ->softirq = softirq;

	unsigned long long curr_idle = idle + iowait;
	unsigned long long curr_total =
	    user + nice + system + idle + iowait + irq + softirq;

	unsigned long long total_diff = curr_total - s->cpu_occ->prev_total;
	unsigned long long idle_diff = curr_idle - s->cpu_occ->prev_idle;

	if (total_diff > 0) {
		s->cpu_occ->cpu = (double)(total_diff - idle_diff) /
				  (double)total_diff * 100.0;
	} else {
		s->cpu_occ->cpu = 0.0; // 防零除
	}

	s->cpu_occ->prev_total = curr_total;
	s->cpu_occ->prev_idle = curr_idle;

	/* EMA - Exponential Moving Average */
	/* DisplayCPU = alpha * raw_cpu + (1 - alpha) * pre_cpu */
	double alpha = 0.1;
	if (total_diff > 0) {
		double raw_cpu = (double)(total_diff - idle_diff) /
				 (double)total_diff * 100.0;
		if (s->cpu_occ->smooth_cpu == 0.0) {
			s->cpu_occ->smooth_cpu = raw_cpu;
		} else {
			s->cpu_occ->smooth_cpu =
			    alpha * raw_cpu +
			    (1 - alpha) * s->cpu_occ->smooth_cpu;
		}

		s->cpu_occ->cpu = raw_cpu;
	}
}