dwn/src/panel.c

/*
 * DWN - Desktop Window Manager
 * Panel system implementation
 */

#include "panel.h"
#include "workspace.h"
#include "layout.h"
#include "client.h"
#include "config.h"
#include "util.h"
#include "atoms.h"
#include "systray.h"
#include "news.h"

#include <string.h>
#include <stdbool.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <X11/Xft/Xft.h>

/* Panel padding and spacing */
#define PANEL_PADDING 8
#define WIDGET_SPACING 12
#define WORKSPACE_WIDTH 28
#define TASKBAR_ITEM_WIDTH 150

/* Clock format */
#define CLOCK_FORMAT "%H:%M:%S"
#define DATE_FORMAT "%Y-%m-%d"

/* Static clock buffer */
static char clock_buffer[32] = "";
static char date_buffer[32] = "";

/* System stats */
typedef struct {
    int cpu_percent;          /* CPU usage percentage */
    int mem_percent;          /* Memory usage percentage */
    int mem_used_mb;          /* Memory used in MB */
    int mem_total_mb;         /* Total memory in MB */
    float load_1min;          /* 1-minute load average */
    float load_5min;          /* 5-minute load average */
    float load_15min;         /* 15-minute load average */
    /* CPU calculation state */
    unsigned long long prev_idle;
    unsigned long long prev_total;
} SystemStats;

static SystemStats sys_stats = {0};

/* Forward declarations */
static void panel_render_system_stats(Panel *panel, int x, int *width);
static int panel_calculate_stats_width(void);

/* ========== UTF-8 text helpers ========== */

/* Get text width using Xft (UTF-8 aware) */
static int panel_text_width(const char *text, int len)
{
    if (text == NULL || dwn == NULL) return 0;

    if (dwn->xft_font != NULL) {
        XGlyphInfo extents;
        XftTextExtentsUtf8(dwn->display, dwn->xft_font,
                           (const FcChar8 *)text, len, &extents);
        return extents.xOff;
    }

    /* Fallback to legacy font */
    if (dwn->font != NULL) {
        return XTextWidth(dwn->font, text, len);
    }

    return 0;
}

/* Draw text using Xft (UTF-8 aware) */
static void panel_draw_text(Drawable d, int x, int y, const char *text,
                            int len, unsigned long color)
{
    if (text == NULL || dwn == NULL || dwn->display == NULL) return;

    /* Use Xft for UTF-8 support */
    if (dwn->xft_font != NULL) {
        XftDraw *xft_draw = XftDrawCreate(dwn->display, d,
                                          DefaultVisual(dwn->display, dwn->screen),
                                          dwn->colormap);
        if (xft_draw != NULL) {
            XftColor xft_color;
            XRenderColor render_color;
            render_color.red = ((color >> 16) & 0xFF) * 257;
            render_color.green = ((color >> 8) & 0xFF) * 257;
            render_color.blue = (color & 0xFF) * 257;
            render_color.alpha = 0xFFFF;

            XftColorAllocValue(dwn->display, DefaultVisual(dwn->display, dwn->screen),
                               dwn->colormap, &render_color, &xft_color);

            XftDrawStringUtf8(xft_draw, &xft_color, dwn->xft_font,
                              x, y, (const FcChar8 *)text, len);

            XftColorFree(dwn->display, DefaultVisual(dwn->display, dwn->screen),
                         dwn->colormap, &xft_color);
            XftDrawDestroy(xft_draw);
            return;
        }
    }

    /* Fallback to legacy X11 text */
    XSetForeground(dwn->display, dwn->gc, color);
    XDrawString(dwn->display, d, dwn->gc, x, y, text, len);
}

/* Get text Y position for vertical centering */
static int panel_text_y(int panel_height)
{
    if (dwn->xft_font != NULL) {
        return (panel_height + dwn->xft_font->ascent) / 2;
    }
    if (dwn->font != NULL) {
        return (panel_height + dwn->font->ascent - dwn->font->descent) / 2;
    }
    return panel_height / 2;
}

/* ========== Panel creation/destruction ========== */

Panel *panel_create(PanelPosition position)
{
    if (dwn == NULL || dwn->display == NULL) {
        return NULL;
    }

    Panel *panel = dwn_calloc(1, sizeof(Panel));
    panel->position = position;
    panel->width = dwn->screen_width;
    panel->height = config_get_panel_height();
    panel->x = 0;
    panel->visible = true;

    if (position == PANEL_TOP) {
        panel->y = 0;
    } else {
        panel->y = dwn->screen_height - panel->height;
    }

    /* Create panel window */
    XSetWindowAttributes swa;
    swa.override_redirect = True;
    swa.background_pixel = dwn->config->colors.panel_bg;
    swa.event_mask = ExposureMask | ButtonPressMask | ButtonReleaseMask;

    panel->window = XCreateWindow(dwn->display, dwn->root,
                                  panel->x, panel->y,
                                  panel->width, panel->height,
                                  0,
                                  CopyFromParent, InputOutput, CopyFromParent,
                                  CWOverrideRedirect | CWBackPixel | CWEventMask,
                                  &swa);

    /* Create double buffer */
    panel->buffer = XCreatePixmap(dwn->display, panel->window,
                                  panel->width, panel->height,
                                  DefaultDepth(dwn->display, dwn->screen));

    /* Set EWMH strut to reserve space */
    long strut[4] = { 0, 0, 0, 0 };
    if (position == PANEL_TOP) {
        strut[2] = panel->height;
    } else {
        strut[3] = panel->height;
    }

    XChangeProperty(dwn->display, panel->window, ewmh.NET_WM_STRUT,
                    XA_CARDINAL, 32, PropModeReplace,
                    (unsigned char *)strut, 4);

    LOG_DEBUG("Created %s panel at y=%d",
              position == PANEL_TOP ? "top" : "bottom", panel->y);

    return panel;
}

void panel_destroy(Panel *panel)
{
    if (panel == NULL) {
        return;
    }

    if (panel->buffer != None) {
        XFreePixmap(dwn->display, panel->buffer);
    }

    if (panel->window != None) {
        XDestroyWindow(dwn->display, panel->window);
    }

    dwn_free(panel);
}

void panels_init(void)
{
    if (dwn == NULL || dwn->config == NULL) {
        return;
    }

    if (dwn->config->top_panel_enabled) {
        dwn->top_panel = panel_create(PANEL_TOP);
        if (dwn->top_panel != NULL) {
            XMapRaised(dwn->display, dwn->top_panel->window);
        }
    }

    if (dwn->config->bottom_panel_enabled) {
        dwn->bottom_panel = panel_create(PANEL_BOTTOM);
        if (dwn->bottom_panel != NULL) {
            XMapRaised(dwn->display, dwn->bottom_panel->window);
        }
    }

    /* Initial clock and stats update */
    panel_update_clock();
    panel_update_system_stats();

    LOG_INFO("Panels initialized");
}

void panels_cleanup(void)
{
    if (dwn->top_panel != NULL) {
        panel_destroy(dwn->top_panel);
        dwn->top_panel = NULL;
    }

    if (dwn->bottom_panel != NULL) {
        panel_destroy(dwn->bottom_panel);
        dwn->bottom_panel = NULL;
    }
}

/* ========== Panel rendering ========== */

void panel_render(Panel *panel)
{
    if (panel == NULL || !panel->visible) {
        return;
    }

    Display *dpy = dwn->display;
    const ColorScheme *colors = config_get_colors();

    /* Clear buffer with background color */
    XSetForeground(dpy, dwn->gc, colors->panel_bg);
    XFillRectangle(dpy, panel->buffer, dwn->gc, 0, 0, panel->width, panel->height);

    int x = PANEL_PADDING;
    int width;

    if (panel->position == PANEL_TOP) {
        /* Top panel: workspaces, layout indicator, taskbar, systray */

        /* Workspace indicators */
        panel_render_workspaces(panel, x, &width);
        x += width + WIDGET_SPACING;

        /* Layout indicator */
        panel_render_layout_indicator(panel, x, &width);
        x += width + WIDGET_SPACING;

        /* Taskbar (takes remaining space, but leave room for systray) */
        panel_render_taskbar(panel, x, &width);

        /* System tray (right side) - WiFi, Audio, etc. */
        int systray_actual_width = systray_get_width();
        int systray_x = panel->width - systray_actual_width - PANEL_PADDING;
        systray_render(panel, systray_x, &width);

        /* AI status (left of systray) */
        if (dwn->ai_enabled) {
            int ai_x = systray_x - 60;
            panel_render_ai_status(panel, ai_x, &width);
        }
    } else {
        /* Bottom panel: date (left), news ticker (center), system stats + clock (right) */

        /* Date (left side) */
        int date_width = 0;
        if (dwn->xft_font != NULL || dwn->font != NULL) {
            int text_y = panel_text_y(panel->height);
            panel_draw_text(panel->buffer, x, text_y, date_buffer,
                            strlen(date_buffer), colors->panel_fg);
            date_width = panel_text_width(date_buffer, strlen(date_buffer));
        }

        /* Calculate positions from right edge */
        int clock_width = panel_text_width(clock_buffer, strlen(clock_buffer));
        int stats_width = panel_calculate_stats_width();

        /* Clock at rightmost position */
        int clock_x = panel->width - clock_width - PANEL_PADDING;
        panel_render_clock(panel, clock_x, &width);

        /* Stats immediately left of clock */
        int stats_x = clock_x - stats_width - WIDGET_SPACING;
        panel_render_system_stats(panel, stats_x, &width);

        /* News ticker between date and stats */
        int news_start = PANEL_PADDING + date_width + WIDGET_SPACING * 2;
        int news_max_width = stats_x - news_start - WIDGET_SPACING;
        if (news_max_width > 100) {  /* Only show if there's reasonable space */
            int news_width = 0;
            news_render(panel, news_start, news_max_width, &news_width);
        }
    }

    /* Copy buffer to window */
    XCopyArea(dpy, panel->buffer, panel->window, dwn->gc,
              0, 0, panel->width, panel->height, 0, 0);

    XFlush(dpy);
}

void panel_render_all(void)
{
    if (dwn->top_panel != NULL) {
        panel_render(dwn->top_panel);
    }
    if (dwn->bottom_panel != NULL) {
        panel_render(dwn->bottom_panel);
    }
}

void panel_render_workspaces(Panel *panel, int x, int *width)
{
    if (panel == NULL || width == NULL) {
        return;
    }

    Display *dpy = dwn->display;
    const ColorScheme *colors = config_get_colors();
    int text_y = panel_text_y(panel->height);

    *width = 0;

    for (int i = 0; i < MAX_WORKSPACES; i++) {
        bool active = (i == dwn->current_workspace);
        bool has_clients = !workspace_is_empty(i);

        /* Background */
        unsigned long bg = active ? colors->workspace_active : colors->panel_bg;
        XSetForeground(dpy, dwn->gc, bg);
        XFillRectangle(dpy, panel->buffer, dwn->gc,
                       x + i * WORKSPACE_WIDTH, 2,
                       WORKSPACE_WIDTH - 2, panel->height - 4);

        /* Workspace number */
        char num[4];
        snprintf(num, sizeof(num), "%d", i + 1);

        unsigned long fg = active ? colors->panel_bg :
                          (has_clients ? colors->panel_fg : colors->workspace_inactive);

        int text_x = x + i * WORKSPACE_WIDTH + (WORKSPACE_WIDTH - panel_text_width(num, strlen(num))) / 2;
        panel_draw_text(panel->buffer, text_x, text_y, num, strlen(num), fg);
    }

    *width = MAX_WORKSPACES * WORKSPACE_WIDTH;
}

void panel_render_taskbar(Panel *panel, int x, int *width)
{
    if (panel == NULL || width == NULL) {
        return;
    }

    Display *dpy = dwn->display;
    const ColorScheme *colors = config_get_colors();
    int text_y = panel_text_y(panel->height);

    int current_x = x;
    int available_width = panel->width - x - 100 - PANEL_PADDING;
    int item_count = 0;

    /* Count visible clients */
    for (Client *c = dwn->client_list; c != NULL; c = c->next) {
        if (c->workspace == (unsigned int)dwn->current_workspace && !client_is_minimized(c)) {
            item_count++;
        }
    }

    if (item_count == 0) {
        *width = 0;
        return;
    }

    int item_width = available_width / item_count;
    if (item_width > TASKBAR_ITEM_WIDTH) {
        item_width = TASKBAR_ITEM_WIDTH;
    }

    /* Render each client */
    Workspace *ws = workspace_get_current();

    for (Client *c = dwn->client_list; c != NULL; c = c->next) {
        if (c->workspace != (unsigned int)dwn->current_workspace || client_is_minimized(c)) {
            continue;
        }

        bool focused = (ws != NULL && ws->focused == c);

        /* Background */
        unsigned long bg = focused ? colors->workspace_active : colors->panel_bg;
        XSetForeground(dpy, dwn->gc, bg);
        XFillRectangle(dpy, panel->buffer, dwn->gc,
                       current_x, 2, item_width - 2, panel->height - 4);

        /* Title - leave room for "..." (4 bytes including null) */
        char title[64];
        strncpy(title, c->title, sizeof(title) - 4);  /* Leave room for "..." */
        title[sizeof(title) - 4] = '\0';

        /* Truncate UTF-8 aware if necessary */
        int max_text_width = item_width - 8;
        bool truncated = false;
        while (panel_text_width(title, strlen(title)) > max_text_width && strlen(title) > 3) {
            size_t len = strlen(title);
            /* Move back to find UTF-8 character boundary */
            size_t cut = len - 1;
            while (cut > 0 && (title[cut] & 0xC0) == 0x80) {
                cut--;  /* Skip continuation bytes */
            }
            if (cut > 0) cut--;
            while (cut > 0 && (title[cut] & 0xC0) == 0x80) {
                cut--;
            }
            /* Ensure we have room for "..." */
            if (cut > sizeof(title) - 4) {
                cut = sizeof(title) - 4;
            }
            title[cut] = '\0';
            truncated = true;
        }
        if (truncated) {
            strncat(title, "...", sizeof(title) - strlen(title) - 1);
        }

        unsigned long fg = focused ? colors->panel_bg : colors->panel_fg;
        panel_draw_text(panel->buffer, current_x + 4, text_y, title, strlen(title), fg);

        current_x += item_width;
    }

    *width = current_x - x;
}

void panel_render_clock(Panel *panel, int x, int *width)
{
    if (panel == NULL || width == NULL) {
        return;
    }
    if (dwn->xft_font == NULL && dwn->font == NULL) {
        return;
    }

    const ColorScheme *colors = config_get_colors();
    int text_y = panel_text_y(panel->height);

    panel_draw_text(panel->buffer, x, text_y, clock_buffer,
                    strlen(clock_buffer), colors->panel_fg);

    *width = panel_text_width(clock_buffer, strlen(clock_buffer));
}

void panel_render_systray(Panel *panel, int x, int *width)
{
    /* System tray placeholder - actual implementation requires
       handling _NET_SYSTEM_TRAY protocol */
    (void)panel;
    (void)x;
    *width = 0;
}

void panel_render_layout_indicator(Panel *panel, int x, int *width)
{
    if (panel == NULL || width == NULL) {
        return;
    }
    if (dwn->xft_font == NULL && dwn->font == NULL) {
        return;
    }

    const ColorScheme *colors = config_get_colors();
    int text_y = panel_text_y(panel->height);

    Workspace *ws = workspace_get_current();
    const char *symbol = layout_get_symbol(ws != NULL ? ws->layout : LAYOUT_TILING);

    panel_draw_text(panel->buffer, x, text_y, symbol, strlen(symbol),
                    colors->workspace_active);

    *width = panel_text_width(symbol, strlen(symbol));
}

void panel_render_ai_status(Panel *panel, int x, int *width)
{
    if (panel == NULL || width == NULL) {
        return;
    }
    if (dwn->xft_font == NULL && dwn->font == NULL) {
        return;
    }

    const ColorScheme *colors = config_get_colors();
    int text_y = panel_text_y(panel->height);

    const char *status = dwn->ai_enabled ? "[AI]" : "";

    panel_draw_text(panel->buffer, x, text_y, status, strlen(status),
                    colors->workspace_active);

    *width = panel_text_width(status, strlen(status));
}

/* ========== Panel interaction ========== */

void panel_handle_click(Panel *panel, int x, int y, int button)
{
    if (panel == NULL) {
        return;
    }

    if (panel->position == PANEL_TOP) {
        /* Check systray click first (right side) */
        int systray_actual_width = systray_get_width();
        int systray_start = panel->width - systray_actual_width - PANEL_PADDING;
        if (x >= systray_start) {
            systray_handle_click(x, y, button);
            return;
        }

        /* Check workspace click */
        int ws = panel_hit_test_workspace(panel, x, y);
        if (ws >= 0 && ws < MAX_WORKSPACES) {
            if (button == 1) {  /* Left click */
                workspace_switch(ws);
            }
            return;
        }

        /* Check taskbar click */
        Client *c = panel_hit_test_taskbar(panel, x, y);
        if (c != NULL) {
            if (button == 1) {
                client_focus(c);
            } else if (button == 3) {  /* Right click */
                client_close(c);
            }
            return;
        }
    } else if (panel->position == PANEL_BOTTOM) {
        /* Bottom panel - click on news opens article in browser */
        if (button == 1) {
            news_handle_click(x, y);
        }
    }
}

int panel_hit_test_workspace(Panel *panel, int x, int y)
{
    (void)y;

    if (panel == NULL || panel->position != PANEL_TOP) {
        return -1;
    }

    if (x < PANEL_PADDING || x >= PANEL_PADDING + MAX_WORKSPACES * WORKSPACE_WIDTH) {
        return -1;
    }

    return (x - PANEL_PADDING) / WORKSPACE_WIDTH;
}

Client *panel_hit_test_taskbar(Panel *panel, int x, int y)
{
    (void)y;

    if (panel == NULL || panel->position != PANEL_TOP) {
        return NULL;
    }

    int taskbar_start = PANEL_PADDING + MAX_WORKSPACES * WORKSPACE_WIDTH + WIDGET_SPACING + 50;
    if (x < taskbar_start) {
        return NULL;
    }

    int available_width = panel->width - taskbar_start - 100 - PANEL_PADDING;
    int item_count = 0;

    for (Client *c = dwn->client_list; c != NULL; c = c->next) {
        if (c->workspace == (unsigned int)dwn->current_workspace && !client_is_minimized(c)) {
            item_count++;
        }
    }

    if (item_count == 0) {
        return NULL;
    }

    int item_width = available_width / item_count;
    if (item_width > TASKBAR_ITEM_WIDTH) {
        item_width = TASKBAR_ITEM_WIDTH;
    }

    int index = (x - taskbar_start) / item_width;
    int i = 0;

    for (Client *c = dwn->client_list; c != NULL; c = c->next) {
        if (c->workspace == (unsigned int)dwn->current_workspace && !client_is_minimized(c)) {
            if (i == index) {
                return c;
            }
            i++;
        }
    }

    return NULL;
}

/* ========== Panel visibility ========== */

void panel_show(Panel *panel)
{
    if (panel == NULL) {
        return;
    }

    panel->visible = true;
    XMapRaised(dwn->display, panel->window);
    panel_render(panel);
}

void panel_hide(Panel *panel)
{
    if (panel == NULL) {
        return;
    }

    panel->visible = false;
    XUnmapWindow(dwn->display, panel->window);
}

void panel_toggle(Panel *panel)
{
    if (panel == NULL) {
        return;
    }

    if (panel->visible) {
        panel_hide(panel);
    } else {
        panel_show(panel);
    }
}

/* ========== Clock updates ========== */

void panel_update_clock(void)
{
    time_t now = time(NULL);
    struct tm *tm_info = localtime(&now);

    strftime(clock_buffer, sizeof(clock_buffer), CLOCK_FORMAT, tm_info);
    strftime(date_buffer, sizeof(date_buffer), DATE_FORMAT, tm_info);
}

/* ========== System stats ========== */

void panel_update_system_stats(void)
{
    FILE *fp;
    char line[256];

    /* Read CPU stats from /proc/stat */
    fp = fopen("/proc/stat", "r");
    if (fp != NULL) {
        if (fgets(line, sizeof(line), fp) != NULL) {
            unsigned long long user, nice, system, idle, iowait, irq, softirq;
            if (sscanf(line, "cpu %llu %llu %llu %llu %llu %llu %llu",
                       &user, &nice, &system, &idle, &iowait, &irq, &softirq) >= 4) {
                unsigned long long total = user + nice + system + idle + iowait + irq + softirq;
                unsigned long long idle_time = idle + iowait;

                if (sys_stats.prev_total > 0) {
                    unsigned long long total_diff = total - sys_stats.prev_total;
                    unsigned long long idle_diff = idle_time - sys_stats.prev_idle;
                    if (total_diff > 0) {
                        sys_stats.cpu_percent = (int)(100 * (total_diff - idle_diff) / total_diff);
                    }
                }

                sys_stats.prev_total = total;
                sys_stats.prev_idle = idle_time;
            }
        }
        fclose(fp);
    }

    /* Read memory stats from /proc/meminfo */
    fp = fopen("/proc/meminfo", "r");
    if (fp != NULL) {
        unsigned long mem_total = 0, mem_free = 0, buffers = 0, cached = 0;

        while (fgets(line, sizeof(line), fp) != NULL) {
            if (strncmp(line, "MemTotal:", 9) == 0) {
                sscanf(line + 9, " %lu", &mem_total);
            } else if (strncmp(line, "MemFree:", 8) == 0) {
                sscanf(line + 8, " %lu", &mem_free);
            } else if (strncmp(line, "Buffers:", 8) == 0) {
                sscanf(line + 8, " %lu", &buffers);
            } else if (strncmp(line, "Cached:", 7) == 0) {
                sscanf(line + 7, " %lu", &cached);
                break;  /* Got all we need */
            }
        }
        fclose(fp);

        if (mem_total > 0) {
            unsigned long used = mem_total - mem_free - buffers - cached;
            sys_stats.mem_total_mb = (int)(mem_total / 1024);
            sys_stats.mem_used_mb = (int)(used / 1024);
            sys_stats.mem_percent = (int)(100 * used / mem_total);
        }
    }

    /* Read load average from /proc/loadavg */
    fp = fopen("/proc/loadavg", "r");
    if (fp != NULL) {
        if (fscanf(fp, "%f %f %f",
                   &sys_stats.load_1min,
                   &sys_stats.load_5min,
                   &sys_stats.load_15min) != 3) {
            sys_stats.load_1min = 0;
            sys_stats.load_5min = 0;
            sys_stats.load_15min = 0;
        }
        fclose(fp);
    }
}

/* Calculate stats width without rendering */
static int panel_calculate_stats_width(void)
{
    if (dwn->xft_font == NULL && dwn->font == NULL) return 0;

    char buf[256];
    int total = 0;

    /* CPU */
    int len = snprintf(buf, sizeof(buf), "CPU:%2d%%", sys_stats.cpu_percent);
    total += panel_text_width(buf, len) + WIDGET_SPACING;

    /* Memory */
    if (sys_stats.mem_total_mb >= 1024) {
        len = snprintf(buf, sizeof(buf), "MEM:%.1fG/%dG",
                       sys_stats.mem_used_mb / 1024.0f, sys_stats.mem_total_mb / 1024);
    } else {
        len = snprintf(buf, sizeof(buf), "MEM:%dM/%dM",
                       sys_stats.mem_used_mb, sys_stats.mem_total_mb);
    }
    total += panel_text_width(buf, len) + WIDGET_SPACING;

    /* Load */
    len = snprintf(buf, sizeof(buf), "Load:%.2f %.2f %.2f",
                   sys_stats.load_1min, sys_stats.load_5min, sys_stats.load_15min);
    total += panel_text_width(buf, len) + WIDGET_SPACING;

    /* Battery - use thread-safe snapshot */
    BatteryState bat_snap = systray_get_battery_snapshot();
    if (bat_snap.present) {
        const char *bat_icon = bat_snap.charging ? "[+]" : "[=]";
        len = snprintf(buf, sizeof(buf), "%s%d%%", bat_icon, bat_snap.percentage);
        total += panel_text_width(buf, len) + WIDGET_SPACING;
    }

    return total;
}

static void panel_render_system_stats(Panel *panel, int x, int *width)
{
    if (panel == NULL || width == NULL) {
        *width = 0;
        return;
    }
    if (dwn->xft_font == NULL && dwn->font == NULL) {
        *width = 0;
        return;
    }

    const ColorScheme *colors = config_get_colors();
    int text_y = panel_text_y(panel->height);
    int current_x = x;

    /* Format: "CPU: 25% | MEM: 4.2G/16G | Load: 1.23 0.98 0.76 | BAT: 85%" */

    char stats_buf[256];
    int len;

    /* CPU with color coding */
    unsigned long cpu_color = colors->panel_fg;
    if (sys_stats.cpu_percent >= 90) {
        cpu_color = colors->workspace_urgent;  /* Red for high CPU */
    } else if (sys_stats.cpu_percent >= 70) {
        cpu_color = 0xFFA500;  /* Orange for medium-high */
    }

    len = snprintf(stats_buf, sizeof(stats_buf), "CPU:%2d%%", sys_stats.cpu_percent);
    panel_draw_text(panel->buffer, current_x, text_y, stats_buf, len, cpu_color);
    current_x += panel_text_width(stats_buf, len) + WIDGET_SPACING;

    /* Memory */
    unsigned long mem_color = colors->panel_fg;
    if (sys_stats.mem_percent >= 90) {
        mem_color = colors->workspace_urgent;
    } else if (sys_stats.mem_percent >= 75) {
        mem_color = 0xFFA500;
    }

    if (sys_stats.mem_total_mb >= 1024) {
        len = snprintf(stats_buf, sizeof(stats_buf), "MEM:%.1fG/%dG",
                       sys_stats.mem_used_mb / 1024.0f, sys_stats.mem_total_mb / 1024);
    } else {
        len = snprintf(stats_buf, sizeof(stats_buf), "MEM:%dM/%dM",
                       sys_stats.mem_used_mb, sys_stats.mem_total_mb);
    }
    panel_draw_text(panel->buffer, current_x, text_y, stats_buf, len, mem_color);
    current_x += panel_text_width(stats_buf, len) + WIDGET_SPACING;

    /* Load average */
    unsigned long load_color = colors->panel_fg;
    if (sys_stats.load_1min >= 4.0f) {
        load_color = colors->workspace_urgent;
    } else if (sys_stats.load_1min >= 2.0f) {
        load_color = 0xFFA500;
    }

    len = snprintf(stats_buf, sizeof(stats_buf), "Load:%.2f %.2f %.2f",
                   sys_stats.load_1min, sys_stats.load_5min, sys_stats.load_15min);
    panel_draw_text(panel->buffer, current_x, text_y, stats_buf, len, load_color);
    current_x += panel_text_width(stats_buf, len) + WIDGET_SPACING;

    /* Battery (if present) - use thread-safe snapshot */
    BatteryState bat_snap = systray_get_battery_snapshot();
    if (bat_snap.present) {
        unsigned long bat_color = colors->panel_fg;
        if (bat_snap.percentage <= 20 && !bat_snap.charging) {
            bat_color = colors->workspace_urgent;  /* Red for low */
        } else if (bat_snap.percentage <= 40 && !bat_snap.charging) {
            bat_color = 0xFFA500;  /* Orange for medium-low */
        } else if (bat_snap.charging) {
            bat_color = colors->workspace_active;  /* Blue for charging */
        }

        const char *bat_icon = bat_snap.charging ? "[+]" : "[=]";
        len = snprintf(stats_buf, sizeof(stats_buf), "%s%d%%", bat_icon, bat_snap.percentage);
        panel_draw_text(panel->buffer, current_x, text_y, stats_buf, len, bat_color);
        current_x += panel_text_width(stats_buf, len) + WIDGET_SPACING;
    }

    *width = current_x - x;
}

/* ========== System tray ========== */

void panel_init_systray(void)
{
    /* System tray initialization - requires _NET_SYSTEM_TRAY protocol */
    LOG_DEBUG("System tray initialization (placeholder)");
}

void panel_add_systray_icon(Window icon)
{
    (void)icon;
    LOG_DEBUG("Add systray icon (placeholder)");
}

void panel_remove_systray_icon(Window icon)
{
    (void)icon;
    LOG_DEBUG("Remove systray icon (placeholder)");
}