/*
 * wfont_x11.c — X11/Xft + PangoXft font backend for WINGs.
 *
 * Per-screen state (ScreenCtxX11): XftDraw + display + screen number.
 * Per-font handle (FontHandleX11): XftFont* + PangoLayout*.
 */

#include "wconfig.h"
#include "WINGsP.h"
#include "WINGs/WINGsX11.h"

#include <X11/Xft/Xft.h>
#include <fontconfig/fontconfig.h>

#ifdef USE_PANGO
#include <pango/pangoxft.h>
#include <pango/pangofc-fontmap.h>
#endif

/* ------------------------------------------------------------------ */

typedef struct {
    Display      *display;
    int           screen_num;
    XftDraw      *xftdraw;
#ifdef USE_PANGO
    PangoFontMap *fontmap;
#endif
} ScreenCtxX11;

typedef struct {
    Display      *display;   /* needed for XftFontClose / XftTextExtentsUtf8 */
    XftFont      *xft;
#ifdef USE_PANGO
    PangoLayout  *layout;
#endif
} FontHandleX11;

/* ------------------------------------------------------------------ */

static void *
x11_screen_init(W_Screen *scr)
{
    ScreenCtxX11 *ctx = wmalloc(sizeof(*ctx));
    ctx->display    = scr->display;
    ctx->screen_num = scr->screen;
    ctx->xftdraw    = XftDrawCreate(scr->display,
                                    W_DRAWABLE(scr),
                                    scr->visual,
                                    scr->colormap);
#ifdef USE_PANGO
    ctx->fontmap = pango_xft_get_font_map(scr->display, scr->screen);
#endif
    return ctx;
}

static void
x11_screen_fini(void *sctx)
{
    ScreenCtxX11 *ctx = sctx;
    XftDrawDestroy(ctx->xftdraw);
    wfree(ctx);
}

static void *
x11_font_open(void *sctx, const char *fc_name, int *height_out, int *y_out)
{
    ScreenCtxX11  *ctx = sctx;
    FontHandleX11 *h   = wmalloc(sizeof(*h));

    h->display = ctx->display;
    h->xft     = XftFontOpenName(ctx->display, ctx->screen_num, fc_name);
    if (!h->xft) {
        wfree(h);
        return NULL;
    }

    *height_out = h->xft->ascent + h->xft->descent;
    *y_out      = h->xft->ascent;

#ifdef USE_PANGO
    {
        PangoContext         *pctx = pango_font_map_create_context(ctx->fontmap);
        FcPattern            *pat  = FcNameParse((FcChar8 *)fc_name);
        PangoFontDescription *desc = pango_fc_font_description_from_pattern(pat, FALSE);
        double                sz   = 0;

        h->layout = pango_layout_new(pctx);
        if (FcPatternGetDouble(pat, FC_PIXEL_SIZE, 0, &sz) == FcResultMatch)
            pango_font_description_set_absolute_size(desc, sz * PANGO_SCALE);
        pango_layout_set_font_description(h->layout, desc);

        pango_font_description_free(desc);
        FcPatternDestroy(pat);
        g_object_unref(pctx);
    }
#endif

    return h;
}

static void
x11_font_close(void *sctx, void *handle)
{
    FontHandleX11 *h = handle;
    (void)sctx;
    if (!h) return;
#ifdef USE_PANGO
    if (h->layout) g_object_unref(h->layout);
#endif
    XftFontClose(h->display, h->xft);
    wfree(h);
}

static int
x11_text_width(void *handle, const char *text, int len)
{
    FontHandleX11 *h = handle;
#ifdef USE_PANGO
    const char *prev = pango_layout_get_text(h->layout);
    if (!prev || strncmp(text, prev, (size_t)len) != 0 || prev[len] != '\0')
        pango_layout_set_text(h->layout, text, len);
    int w = 0;
    pango_layout_get_pixel_size(h->layout, &w, NULL);
    return w;
#else
    XGlyphInfo ext;
    XftTextExtentsUtf8(h->display, h->xft, (XftChar8 *)text, len, &ext);
    return ext.xOff;
#endif
}

static void
x11_draw_string(void *sctx, void *handle, WMDrawable d,
                int x, int y,
                unsigned short r, unsigned short g,
                unsigned short b, unsigned short a,
                unsigned long pixel,
                const char *text, int len)
{
    ScreenCtxX11  *ctx = sctx;
    FontHandleX11 *h   = handle;
    XftColor       xc  = { .pixel = pixel,
                            .color = { .red=r, .green=g, .blue=b, .alpha=a } };

    XftDrawChange(ctx->xftdraw, (Drawable)d);

#ifdef USE_PANGO
    const char *prev = pango_layout_get_text(h->layout);
    if (!prev || strcmp(text, prev) != 0)
        pango_layout_set_text(h->layout, text, len);
    pango_xft_render_layout(ctx->xftdraw, &xc, h->layout,
                            x * PANGO_SCALE, y * PANGO_SCALE);
#else
    XftDrawStringUtf8(ctx->xftdraw, &xc, h->xft,
                      x, y + h->xft->ascent,
                      (XftChar8 *)text, len);
#endif
}

static void
x11_draw_image_string(void *sctx, void *handle, WMDrawable d,
                      int x, int y,
                      unsigned short tr, unsigned short tg,
                      unsigned short tb, unsigned short ta, unsigned long tpix,
                      unsigned short br, unsigned short bg,
                      unsigned short bb, unsigned short ba, unsigned long bpix,
                      int bg_w, int bg_h,
                      const char *text, int len)
{
    ScreenCtxX11  *ctx = sctx;
    FontHandleX11 *h   = handle;
    XftColor       tc  = { .pixel = tpix,
                            .color = { .red=tr, .green=tg, .blue=tb, .alpha=ta } };
    XftColor       bc  = { .pixel = bpix,
                            .color = { .red=br, .green=bg, .blue=bb, .alpha=ba } };

    XftDrawChange(ctx->xftdraw, (Drawable)d);
    XftDrawRect(ctx->xftdraw, &bc, x, y, (unsigned)bg_w, (unsigned)bg_h);

#ifdef USE_PANGO
    const char *prev = pango_layout_get_text(h->layout);
    if (!prev || strcmp(text, prev) != 0)
        pango_layout_set_text(h->layout, text, len);
    pango_xft_render_layout(ctx->xftdraw, &tc, h->layout,
                            x * PANGO_SCALE, y * PANGO_SCALE);
#else
    XftDrawStringUtf8(ctx->xftdraw, &tc, h->xft,
                      x, y + h->xft->ascent,
                      (XftChar8 *)text, len);
#endif
}

static int
x11_lookup_string(void *sctx, W_View *view, WMEvent *event,
                  char *buffer, int buflen, unsigned long *keysym_out)
{
    (void)sctx;
    if (!event->_x11_raw) { *keysym_out = 0; return 0; }
    return W_LookupString(view, &((XEvent *)event->_x11_raw)->xkey,
                          buffer, buflen, (KeySym *)keysym_out, NULL);
}

const W_FontBackend W_FontBackendX11 = {
    .screen_init       = x11_screen_init,
    .screen_fini       = x11_screen_fini,
    .font_open         = x11_font_open,
    .font_close        = x11_font_close,
    .text_width        = x11_text_width,
    .draw_string       = x11_draw_string,
    .draw_image_string = x11_draw_image_string,
    .lookup_string     = x11_lookup_string,
};