#include "nuklear.h"
#include "nuklear_internal.h"

/* ===============================================================
 *
 *                          GROUP
 *
 * ===============================================================*/
NK_API int
nk_group_scrolled_offset_begin(struct nk_context *ctx,
    nk_uint *x_offset, nk_uint *y_offset, const char *title, nk_flags flags)
{
    struct nk_rect bounds;
    struct nk_window panel;
    struct nk_window *win;

    win = ctx->current;
    nk_panel_alloc_space(&bounds, ctx);
    {const struct nk_rect *c = &win->layout->clip;
    if (!NK_INTERSECT(c->x, c->y, c->w, c->h, bounds.x, bounds.y, bounds.w, bounds.h) &&
        !(flags & NK_WINDOW_MOVABLE)) {
        return 0;
    }}
    if (win->flags & NK_WINDOW_ROM)
        flags |= NK_WINDOW_ROM;

    /* initialize a fake window to create the panel from */
    nk_zero(&panel, sizeof(panel));
    panel.bounds = bounds;
    panel.flags = flags;
    panel.scrollbar.x = *x_offset;
    panel.scrollbar.y = *y_offset;
    panel.buffer = win->buffer;
    panel.layout = (struct nk_panel*)nk_create_panel(ctx);
    ctx->current = &panel;
    nk_panel_begin(ctx, (flags & NK_WINDOW_TITLE) ? title: 0, NK_PANEL_GROUP);

    win->buffer = panel.buffer;
    win->buffer.clip = panel.layout->clip;
    panel.layout->offset_x = x_offset;
    panel.layout->offset_y = y_offset;
    panel.layout->parent = win->layout;
    win->layout = panel.layout;

    ctx->current = win;
    if ((panel.layout->flags & NK_WINDOW_CLOSED) ||
        (panel.layout->flags & NK_WINDOW_MINIMIZED))
    {
        nk_flags f = panel.layout->flags;
        nk_group_scrolled_end(ctx);
        if (f & NK_WINDOW_CLOSED)
            return NK_WINDOW_CLOSED;
        if (f & NK_WINDOW_MINIMIZED)
            return NK_WINDOW_MINIMIZED;
    }
    return 1;
}
NK_API void
nk_group_scrolled_end(struct nk_context *ctx)
{
    struct nk_window *win;
    struct nk_panel *parent;
    struct nk_panel *g;

    struct nk_rect clip;
    struct nk_window pan;
    struct nk_vec2 panel_padding;

    NK_ASSERT(ctx);
    NK_ASSERT(ctx->current);
    if (!ctx || !ctx->current)
        return;

    /* make sure nk_group_begin was called correctly */
    NK_ASSERT(ctx->current);
    win = ctx->current;
    NK_ASSERT(win->layout);
    g = win->layout;
    NK_ASSERT(g->parent);
    parent = g->parent;

    /* dummy window */
    nk_zero_struct(pan);
    panel_padding = nk_panel_get_padding(&ctx->style, NK_PANEL_GROUP);
    pan.bounds.y = g->bounds.y - (g->header_height + g->menu.h);
    pan.bounds.x = g->bounds.x - panel_padding.x;
    pan.bounds.w = g->bounds.w + 2 * panel_padding.x;
    pan.bounds.h = g->bounds.h + g->header_height + g->menu.h;
    if (g->flags & NK_WINDOW_BORDER) {
        pan.bounds.x -= g->border;
        pan.bounds.y -= g->border;
        pan.bounds.w += 2*g->border;
        pan.bounds.h += 2*g->border;
    }
    if (!(g->flags & NK_WINDOW_NO_SCROLLBAR)) {
        pan.bounds.w += ctx->style.window.scrollbar_size.x;
        pan.bounds.h += ctx->style.window.scrollbar_size.y;
    }
    pan.scrollbar.x = *g->offset_x;
    pan.scrollbar.y = *g->offset_y;
    pan.flags = g->flags;
    pan.buffer = win->buffer;
    pan.layout = g;
    pan.parent = win;
    ctx->current = &pan;

    /* make sure group has correct clipping rectangle */
    nk_unify(&clip, &parent->clip, pan.bounds.x, pan.bounds.y,
        pan.bounds.x + pan.bounds.w, pan.bounds.y + pan.bounds.h + panel_padding.x);
    nk_push_scissor(&pan.buffer, clip);
    nk_end(ctx);

    win->buffer = pan.buffer;
    nk_push_scissor(&win->buffer, parent->clip);
    ctx->current = win;
    win->layout = parent;
    g->bounds = pan.bounds;
    return;
}
NK_API int
nk_group_scrolled_begin(struct nk_context *ctx,
    struct nk_scroll *scroll, const char *title, nk_flags flags)
{
    return nk_group_scrolled_offset_begin(ctx, &scroll->x, &scroll->y, title, flags);
}
NK_API int
nk_group_begin_titled(struct nk_context *ctx, const char *id,
    const char *title, nk_flags flags)
{
    int id_len;
    nk_hash id_hash;
    struct nk_window *win;
    nk_uint *x_offset;
    nk_uint *y_offset;

    NK_ASSERT(ctx);
    NK_ASSERT(id);
    NK_ASSERT(ctx->current);
    NK_ASSERT(ctx->current->layout);
    if (!ctx || !ctx->current || !ctx->current->layout || !id)
        return 0;

    /* find persistent group scrollbar value */
    win = ctx->current;
    id_len = (int)nk_strlen(id);
    id_hash = nk_murmur_hash(id, (int)id_len, NK_PANEL_GROUP);
    x_offset = nk_find_value(win, id_hash);
    if (!x_offset) {
        x_offset = nk_add_value(ctx, win, id_hash, 0);
        y_offset = nk_add_value(ctx, win, id_hash+1, 0);

        NK_ASSERT(x_offset);
        NK_ASSERT(y_offset);
        if (!x_offset || !y_offset) return 0;
        *x_offset = *y_offset = 0;
    } else y_offset = nk_find_value(win, id_hash+1);
    return nk_group_scrolled_offset_begin(ctx, x_offset, y_offset, title, flags);
}
NK_API int
nk_group_begin(struct nk_context *ctx, const char *title, nk_flags flags)
{
    return nk_group_begin_titled(ctx, title, title, flags);
}
NK_API void
nk_group_end(struct nk_context *ctx)
{
    nk_group_scrolled_end(ctx);
}

