/*
 * DWN - Desktop Window Manager
 * Window decorations implementation
 */

#include "decorations.h"
#include "client.h"
#include "config.h"
#include "util.h"

#include <string.h>
#include <stdbool.h>
#include <X11/Xft/Xft.h>

/* Button dimensions */
#define BUTTON_SIZE 16
#define BUTTON_PADDING 4

/* Resize edge size */
#define RESIZE_EDGE 8

/* ========== Initialization ========== */

void decorations_init(void)
{
    LOG_DEBUG("Decorations system initialized");
}

void decorations_cleanup(void)
{
    /* Nothing to clean up */
}

/* ========== Rendering ========== */

void decorations_render(Client *client, bool focused)
{
    if (client == NULL || client->frame == None) {
        return;
    }

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

    decorations_render_title_bar(client, focused);
    decorations_render_buttons(client, focused);
    decorations_render_border(client, focused);
}

void decorations_render_title_bar(Client *client, bool focused)
{
    if (client == NULL || client->frame == None) {
        return;
    }

    if (dwn == NULL || dwn->display == NULL || dwn->gc == None || dwn->config == NULL) {
        return;
    }

    Display *dpy = dwn->display;
    const ColorScheme *colors = config_get_colors();
    int title_height = config_get_title_height();
    int border = client->border_width;

    /* Set colors based on focus */
    unsigned long bg_color = focused ? colors->title_focused_bg : colors->title_unfocused_bg;
    unsigned long fg_color = focused ? colors->title_focused_fg : colors->title_unfocused_fg;

    /* Draw title bar background */
    XSetForeground(dpy, dwn->gc, bg_color);
    XFillRectangle(dpy, client->frame, dwn->gc,
                   border, border,
                   client->width, title_height);

    /* Draw title text */
    if (client->title[0] != '\0' && dwn->xft_font != NULL) {
        int text_y = border + (title_height + dwn->xft_font->ascent) / 2;
        int text_x = border + BUTTON_PADDING;

        /* Truncate title if too long */
        int max_width = client->width - 3 * (BUTTON_SIZE + BUTTON_PADDING) - 2 * BUTTON_PADDING;
        char display_title[256];
        strncpy(display_title, client->title, sizeof(display_title) - 4);  /* Leave room for "..." */
        display_title[sizeof(display_title) - 4] = '\0';

        XGlyphInfo extents;
        XftTextExtentsUtf8(dpy, dwn->xft_font,
                           (const FcChar8 *)display_title, strlen(display_title), &extents);
        int text_width = extents.xOff;

        /* Truncate UTF-8 aware: find valid UTF-8 boundary */
        bool title_truncated = false;
        while (text_width > max_width && strlen(display_title) > 3) {
            size_t len = strlen(display_title);
            /* Move back to find UTF-8 character boundary */
            size_t cut = len - 1;
            while (cut > 0 && (display_title[cut] & 0xC0) == 0x80) {
                cut--;  /* Skip continuation bytes */
            }
            if (cut > 0) cut--;  /* Remove one more character for ellipsis space */
            while (cut > 0 && (display_title[cut] & 0xC0) == 0x80) {
                cut--;
            }
            display_title[cut] = '\0';
            title_truncated = true;

            XftTextExtentsUtf8(dpy, dwn->xft_font,
                               (const FcChar8 *)display_title, strlen(display_title), &extents);
            text_width = extents.xOff;
        }
        if (title_truncated) {
            strncat(display_title, "...", sizeof(display_title) - strlen(display_title) - 1);
        }

        /* Draw with Xft for UTF-8 support */
        XftDraw *xft_draw = XftDrawCreate(dpy, client->frame,
                                          DefaultVisual(dpy, dwn->screen),
                                          dwn->colormap);
        if (xft_draw != NULL) {
            XftColor xft_color;
            XRenderColor render_color;
            render_color.red = ((fg_color >> 16) & 0xFF) * 257;
            render_color.green = ((fg_color >> 8) & 0xFF) * 257;
            render_color.blue = (fg_color & 0xFF) * 257;
            render_color.alpha = 0xFFFF;

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

            XftDrawStringUtf8(xft_draw, &xft_color, dwn->xft_font,
                              text_x, text_y,
                              (const FcChar8 *)display_title, strlen(display_title));

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

void decorations_render_buttons(Client *client, bool focused)
{
    if (client == NULL || client->frame == None) {
        return;
    }

    if (dwn == NULL || dwn->display == NULL || dwn->gc == None || dwn->config == NULL) {
        return;
    }

    Display *dpy = dwn->display;
    const ColorScheme *colors = config_get_colors();
    int title_height = config_get_title_height();
    int border = client->border_width;

    /* Button positions (right-aligned) */
    int button_y = border + (title_height - BUTTON_SIZE) / 2;
    int close_x = border + client->width - BUTTON_SIZE - BUTTON_PADDING;
    int max_x = close_x - BUTTON_SIZE - BUTTON_PADDING;
    int min_x = max_x - BUTTON_SIZE - BUTTON_PADDING;

    unsigned long bg_color = focused ? colors->title_focused_bg : colors->title_unfocused_bg;

    /* Close button (red X) */
    XSetForeground(dpy, dwn->gc, bg_color);
    XFillRectangle(dpy, client->frame, dwn->gc, close_x, button_y, BUTTON_SIZE, BUTTON_SIZE);
    XSetForeground(dpy, dwn->gc, 0xcc4444);  /* Red */
    XDrawLine(dpy, client->frame, dwn->gc,
              close_x + 3, button_y + 3,
              close_x + BUTTON_SIZE - 4, button_y + BUTTON_SIZE - 4);
    XDrawLine(dpy, client->frame, dwn->gc,
              close_x + BUTTON_SIZE - 4, button_y + 3,
              close_x + 3, button_y + BUTTON_SIZE - 4);

    /* Maximize button (square) */
    XSetForeground(dpy, dwn->gc, bg_color);
    XFillRectangle(dpy, client->frame, dwn->gc, max_x, button_y, BUTTON_SIZE, BUTTON_SIZE);
    XSetForeground(dpy, dwn->gc, 0x44cc44);  /* Green */
    XDrawRectangle(dpy, client->frame, dwn->gc,
                   max_x + 3, button_y + 3,
                   BUTTON_SIZE - 7, BUTTON_SIZE - 7);

    /* Minimize button (line) */
    XSetForeground(dpy, dwn->gc, bg_color);
    XFillRectangle(dpy, client->frame, dwn->gc, min_x, button_y, BUTTON_SIZE, BUTTON_SIZE);
    XSetForeground(dpy, dwn->gc, 0xcccc44);  /* Yellow */
    XDrawLine(dpy, client->frame, dwn->gc,
              min_x + 3, button_y + BUTTON_SIZE - 5,
              min_x + BUTTON_SIZE - 4, button_y + BUTTON_SIZE - 5);
}

void decorations_render_border(Client *client, bool focused)
{
    if (client == NULL || client->frame == None) {
        return;
    }

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

    const ColorScheme *colors = config_get_colors();
    unsigned long border_color = focused ? colors->border_focused : colors->border_unfocused;

    XSetWindowBorder(dwn->display, client->frame, border_color);
}

/* ========== Hit testing ========== */

ButtonType decorations_hit_test_button(Client *client, int x, int y)
{
    if (client == NULL) {
        return BUTTON_COUNT;  /* No button hit */
    }

    int title_height = config_get_title_height();
    int border = client->border_width;

    /* Check if in title bar area */
    if (y < border || y > border + title_height) {
        return BUTTON_COUNT;
    }

    int button_y = border + (title_height - BUTTON_SIZE) / 2;
    int close_x = border + client->width - BUTTON_SIZE - BUTTON_PADDING;
    int max_x = close_x - BUTTON_SIZE - BUTTON_PADDING;
    int min_x = max_x - BUTTON_SIZE - BUTTON_PADDING;

    /* Check close button */
    if (x >= close_x && x < close_x + BUTTON_SIZE &&
        y >= button_y && y < button_y + BUTTON_SIZE) {
        return BUTTON_CLOSE;
    }

    /* Check maximize button */
    if (x >= max_x && x < max_x + BUTTON_SIZE &&
        y >= button_y && y < button_y + BUTTON_SIZE) {
        return BUTTON_MAXIMIZE;
    }

    /* Check minimize button */
    if (x >= min_x && x < min_x + BUTTON_SIZE &&
        y >= button_y && y < button_y + BUTTON_SIZE) {
        return BUTTON_MINIMIZE;
    }

    return BUTTON_COUNT;
}

bool decorations_hit_test_title_bar(Client *client, int x, int y)
{
    if (client == NULL) {
        return false;
    }

    int title_height = config_get_title_height();
    int border = client->border_width;

    /* In title bar but not on a button */
    if (y >= border && y < border + title_height) {
        ButtonType btn = decorations_hit_test_button(client, x, y);
        return btn == BUTTON_COUNT;
    }

    return false;
}

bool decorations_hit_test_resize_area(Client *client, int x, int y, int *direction)
{
    if (client == NULL || direction == NULL) {
        return false;
    }

    int title_height = config_get_title_height();
    int border = client->border_width;
    int frame_width = client->width + 2 * border;
    int frame_height = client->height + title_height + 2 * border;

    *direction = 0;

    /* Check edges */
    bool left = (x < RESIZE_EDGE);
    bool right = (x > frame_width - RESIZE_EDGE);
    bool top = (y < RESIZE_EDGE);
    bool bottom = (y > frame_height - RESIZE_EDGE);

    if (!left && !right && !top && !bottom) {
        return false;
    }

    /* Encode direction as bitmask */
    if (left)   *direction |= 1;
    if (right)  *direction |= 2;
    if (top)    *direction |= 4;
    if (bottom) *direction |= 8;

    return true;
}

/* ========== Button actions ========== */

void decorations_button_press(Client *client, ButtonType button)
{
    if (client == NULL) {
        return;
    }

    switch (button) {
        case BUTTON_CLOSE:
            LOG_DEBUG("Close button pressed for %s", client->title);
            client_close(client);
            break;

        case BUTTON_MAXIMIZE:
            LOG_DEBUG("Maximize button pressed for %s", client->title);
            client_toggle_fullscreen(client);
            break;

        case BUTTON_MINIMIZE:
            LOG_DEBUG("Minimize button pressed for %s", client->title);
            client_minimize(client);
            break;

        default:
            break;
    }
}

/* ========== Text rendering ========== */

void decorations_draw_text(Window window, GC gc, int x, int y,
                           const char *text, 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, window,
                                          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, strlen(text));

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

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