#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <stdlib.h>
#include <wayland-server-core.h>
#include <wlr/types/wlr_scene.h>
#include <wlr/types/wlr_xdg_shell.h>
#include <wlr/xwayland.h>
#include "../../screen.h"
#include "wl_types.h"

struct wl_frame_buf *frame_buf_find(WNativeWindow id);
struct wl_toplevel_view *wl_find_view_by_id(WNativeWindow id);


/* ------------------------------------------------------------------ */
/* Stacking                                                            */
/* ------------------------------------------------------------------ */

/* Map a WM window level integer to a level_trees[] bucket index.
 * Buckets are ordered 0=lowest (WL_LAYER_BACKGROUND) to 8=highest
 * (WL_LAYER_OVERLAY), matching the bottom-to-top creation order of
 * level_trees[].  Does not map WL_LAYER_BACKGROUND (no WM level). */
int
level_to_bucket(int level)
{
    if (level < -1)  return WL_LAYER_DESKTOP;
    if (level < 0)   return WL_LAYER_SUNKEN;
    if (level < 3)   return WL_LAYER_NORMAL;
    if (level < 20)  return WL_LAYER_FLOATING;
    if (level < 21)  return WL_LAYER_MENU;
    if (level < 50)  return WL_LAYER_DOCK;
    if (level < 100) return WL_LAYER_FULLSCREEN;
    return WL_LAYER_OVERLAY;
}

/* Return the level_trees[] entry for a given WM level integer.
 * Falls back to the root scene tree only if the scene is not yet
 * initialised, which cannot happen during normal window management. */
struct wlr_scene_tree *
level_tree_for(int level)
{
    int b = level_to_bucket(level);
    if (wl_state.level_trees[b])
        return wl_state.level_trees[b];
    /* Scene not yet initialised — this window will be invisible. */
    return &wl_state.scene->tree;
}

void
wl_stacking_set_level(WNativeWindow win, int level)
{
    /* Move the frame's grouping tree into the correct level bucket so
     * that the scene graph structurally enforces level ordering.  All
     * other nodes (background rect, dock panel, OR views, overlays)
     * are already placed in their fixed buckets at creation time. */
    struct wl_frame_buf *fb = frame_buf_find(win);
    if (!fb || !fb->tree) return;
    struct wlr_scene_tree *target = level_tree_for(level);
    if (fb->tree->node.parent != target)
        wlr_scene_node_reparent(&fb->tree->node, target);
}

void
wl_stacking_raise(WNativeWindow win)
{
    struct wl_toplevel_view *v = wl_find_view_by_id(win);
    if (v) {
        wl_list_remove(&v->link);
        wl_list_insert(&wl_state.toplevel_list, &v->link);
        if (v->frame_id) {
            struct wl_frame_buf *fb = frame_buf_find(v->frame_id);
            if (fb && fb->tree) {
                wlr_scene_node_raise_to_top(&fb->tree->node);
                return;
            }
        }
        if (v->scene_node)
            wlr_scene_node_raise_to_top(&v->scene_node->node);
        return;
    }
    struct wl_frame_buf *fb = frame_buf_find(win);
    if (fb) {
        if (fb->tree) {
            wlr_scene_node_raise_to_top(&fb->tree->node);
        } else if (fb->scene_buf) {
            wlr_scene_node_raise_to_top(&fb->scene_buf->node);
        }
        return;
    }
}

void
wl_stacking_lower(WNativeWindow win)
{
    /* Frame-buf path: operate on the grouping tree, not the inner buffer
     * node.  Lowering fb->tree moves the whole window (frame pixels +
     * reparented client surface) together, within its level bucket. */
    struct wl_frame_buf *fb = frame_buf_find(win);
    if (fb) {
        if (fb->tree)
            wlr_scene_node_lower_to_bottom(&fb->tree->node);
        else if (fb->scene_buf)
            wlr_scene_node_lower_to_bottom(&fb->scene_buf->node);
        return;
    }
    /* Unframed toplevel view (no frame_buf wrapper). */
    struct wl_toplevel_view *v = wl_find_view_by_id(win);
    if (v) {
        wl_list_remove(&v->link);
        wl_list_insert(wl_state.toplevel_list.prev, &v->link);
        if (v->scene_node)
            wlr_scene_node_lower_to_bottom(&v->scene_node->node);
    }
}

void
wl_stacking_restack(WNativeWindow *windows, int count)
{
    /* Reorder scene graph to match the WM stacking order.
     *
     * windows[] is ordered top-to-bottom (index 0 = topmost).
     * Process bottom-to-top: last raise_to_top call wins, so the
     * window at index 0 ends up on top within its level bucket.
     *
     * Each window is represented by its toplevel frame_buf ID.  We
     * raise fb->tree — the grouping tree that owns both the frame
     * pixel buffer and the reparented client surface — so the entire
     * window moves as one atomic unit.  Child frame_bufs (titlebar,
     * resizebar) are already children of fb->tree and move with it. */
    int i;
    for (i = count - 1; i >= 0; i--) {
        WNativeWindow win = windows[i];
        struct wl_frame_buf *fb = frame_buf_find(win);
        if (fb) {
            /* Raise the grouping tree: moves frame + client together. */
            if (fb->tree)
                wlr_scene_node_raise_to_top(&fb->tree->node);
            else if (fb->scene_buf)
                wlr_scene_node_raise_to_top(&fb->scene_buf->node);
            continue;
        }
        /* Fallback: unframed toplevel view (no frame_buf). */
        struct wl_toplevel_view *v = wl_find_view_by_id(win);
        if (v) {
            wl_list_remove(&v->link);
            wl_list_insert(&wl_state.toplevel_list, &v->link);
            if (v->scene_node)
                wlr_scene_node_raise_to_top(&v->scene_node->node);
        }
    }
}

int
wl_stacking_query(WNativeWindow root,
                  WNativeWindow **out, unsigned int *count)
{
    /* return synthetic IDs in Z-order (top to bottom).
     * RemakeStackList will find no WM_CTX_STACK entries for them
     * and set window_count=0, but returning 1 avoids the "could not
     * get window list" warning. */
    struct wl_toplevel_view *v;
    unsigned int n = 0, i = 0;
    WNativeWindow *wins;
    (void)root;

    wl_list_for_each(v, &wl_state.toplevel_list, link) n++;
    if (n == 0) { *out = NULL; *count = 0; return 1; }

    wins = wmalloc(n * sizeof(WNativeWindow));
    wl_list_for_each(v, &wl_state.toplevel_list, link) wins[i++] = v->id;
    *out = wins; *count = n;
    return 1;
}