#include <glib.h>
#include <math.h>
#include <pango/pangocairo.h>
#include <pango/pango-font.h>
#include <pango/pango-types.h>

#include "draw.h"
#include "button.h"
#include "log.h"

// Idea: Either make a to_draw queue where we put things we schedule to redraw
// (this will also work for animations in the future)
// or use some flags to trigger drawing

static void layout_destroy(Layout *layout)
{
    g_object_unref(layout->pl);
    g_free(layout);
}

Drawable *draw_create(const char *font, int height, int left_pad, int right_pad, int top_pad, double alpha)
{
    Drawable *draw = g_malloc(sizeof(Drawable));
    g_assert_nonnull(draw);

    log_debug("Pango loading font description '%s'", font);
    draw->desc = pango_font_description_from_string(font);
    log_debug("Pango found matching font '%s'", pango_font_description_get_family(draw->desc));

    draw->height = height;
    draw->left_pad = left_pad;
    draw->right_pad = right_pad;
    draw->top_pad = top_pad;
    draw->alpha = alpha;
    g_assert(alpha >= 0 && alpha <= 1);

    draw->layouts = NULL;

    log_debug("Draw context created [height=%d, left_pad=%d, right_pad=%d, top_pad=%d, alpha=%.2lf]", height, left_pad, right_pad, top_pad, alpha);

    return draw;
}

void draw_paint(Drawable *draw, Window *win)
{
    // FIXME: Does not work for scale != 1
    //double scale = window_get_scale(win);
    double scale = 1;

    int screen_width, screen_height;
    window_get_screen_size(win, &screen_width, &screen_height);

    int width0  = screen_width - draw->right_pad - draw->left_pad;
    int width  = round(width0 * scale);
    int height = round(draw->height * scale);

    cairo_surface_t *surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height);

    cairo_t *cr = cairo_create(surface);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
    cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);

    int radius = height / 2;
    double degree = M_PI / 180.0;

    cairo_set_source_rgba(cr, 0.3, 0.3, 0.3, draw->alpha);

    // TODO: Here we should paint the shape of the bar, however there is a problem with the surface
    //       painted in the pixmap to mask the window shape in window_paint_corners.
    //
    //       This is caused by some difference between the two shapes (that should technically be the same)
    //       which causes a mismatch between the two layers and leaves some black pixels visible

    //cairo_arc(cr, radius, radius, radius, 90.0 * degree, 270 * degree);
    //cairo_arc(cr, width - radius, radius, radius, 270 * degree, 450 * degree);
    //cairo_fill(cr);

    cairo_paint(cr);

    int line_w = 1 * scale;
    cairo_set_line_width(cr, line_w);

    for (GList *it = draw->layouts; it; it = it->next) {
        Layout *layout = it->data;

        int text_x = layout->x + (layout->width / 2) - (layout->text_w / 2);
        int text_y = layout->y + (layout->height / 2) - (layout->text_h / 2);

        // purple
        cairo_set_source_rgba(cr, 0.502, 0.168, 0.886, 1);
        cairo_new_sub_path(cr);
        cairo_arc(cr, layout->x + radius, layout->y + radius, radius, 90 * degree, 270 * degree);
        cairo_arc(cr, layout->x + layout->width - radius, layout->y + radius, radius, 270 * degree, 450 * degree);
        cairo_close_path(cr);
        cairo_fill(cr);

        cairo_set_source_rgba(cr, 0.8, 0.8, 0.8, 1);
        cairo_new_sub_path(cr);
        cairo_arc(cr, layout->x + radius, layout->y + radius, radius - line_w , 90 * degree, 270 * degree);
        cairo_arc(cr, layout->x + layout->width - radius, layout->y + radius, radius - line_w, 270 * degree, 450 * degree);
        cairo_close_path(cr);
        cairo_stroke(cr);

        cairo_set_source_rgb(cr, 0.8, 0.8, 0.8);
        cairo_move_to(cr, text_x, text_y);

        pango_cairo_update_layout(cr, layout->pl);
        pango_cairo_show_layout(cr, layout->pl);
    }

    cairo_destroy(cr);

    // TODO: Move these somewhere else
    window_move(win, draw->left_pad, draw->top_pad);
    window_resize(win, width0, draw->height);

    window_paint_surface(win, surface, width, height);
    cairo_surface_destroy(surface);
}

void draw_compute_layout(Drawable *draw, GList *btns, cairo_t *cr)
{
    g_list_free_full(draw->layouts, (GDestroyNotify)layout_destroy);
    draw->layouts = NULL;

    // FIXME: Does not work for scale != 1
    //double scale = window_get_scale(win);
    double scale = 1;

    int x = 0;
    int height = round(draw->height * scale);
    int radius = height / 2;

    for (GList *it = btns; it; it = it->next) {
        Button *btn = it->data;

        Layout *layout = g_malloc(sizeof(Layout));
        layout->btn = btn;

        layout->x = x;
        layout->y = 0;

        layout->pl = pango_cairo_create_layout(cr);
        pango_layout_set_font_description(layout->pl, draw->desc);
        pango_layout_set_text(layout->pl, btn->text, -1);
        pango_layout_set_alignment(layout->pl, PANGO_ALIGN_CENTER);

        int text_w, text_h;
        pango_layout_get_pixel_size(layout->pl, &text_w, &text_h);

        layout->text_w = ceil(text_w / scale);
        layout->text_h = ceil(text_h / scale);

        layout->width = btn->fixed_size ? height : layout->text_w + 2 * radius;
        layout->height = height;

        draw->layouts = g_list_append(draw->layouts, layout);

        int sep = 10 * scale;
        int line_w = 1 * scale;
        x += height + line_w * 2 + sep;
    }

    log_debug("Updated layouts");
}

void draw_destroy(Drawable *draw)
{
    g_list_free_full(draw->layouts, (GDestroyNotify)layout_destroy);
    pango_font_description_free(draw->desc);
    g_free(draw);
}

// vim: ts=4 sw=4 et