#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <glib-2.0/glib.h>
#include <gtk-4.0/gtk/gtk.h>

// Simplified TreeNode structure for demonstration purposes
struct TreeNode_t
{
    gchar *text;
    struct TreeNode_t *child;
    struct TreeNode_t *next;
};

struct TreeNode_t *root = NULL;


// Function to create a new TreeNode instance
struct TreeNode_t *create_tree_node (const gchar* text)
{
    struct TreeNode_t *node = g_malloc0 (sizeof(struct TreeNode_t));
    node->text = g_strdup(text);
    node->child = NULL;
    return node;
}

// Function to add a child node to a parent node
void add_child_node (struct TreeNode_t *parent, struct TreeNode_t *child)
{
    struct TreeNode_t *cur;

    if (parent->child) {
        cur = parent->child;
        while (cur && cur->next) {
            cur = cur->next;
        }
        cur->next = child;
    } else {
        parent->child = child;
    }
}

// Recursive function to free a TreeNode and its children
void free_tree_node (struct TreeNode_t *node)
{
    struct TreeNode_t *cur;
    struct TreeNode_t *tmp;

    if (!node) return;
    
    // free siblings
    cur = node;
    while (cur) {
        tmp = cur->next;
        g_free(cur);
        cur = tmp;
    }
    
    // recursive free
    free_tree_node(node->child);
    g_free(node->text);
    g_free(node);
}

// Function to simulate getting a GListModel of children for a given TreeNode
GListModel* get_children_model (struct TreeNode_t *parent)
{
    struct TreeNode_t *child;

    GtkStringList *list = gtk_string_list_new(NULL);
    
    if (parent) {
        child = parent->child;
        while(child) {
             gtk_string_list_append(list, child->text);
             child = child->next;
        }
    }
    return G_LIST_MODEL(list);
}

// GtkTreeListModelCreateModelFunc callback implementation
GListModel* create_model_func(GObject *item, gpointer user_data)
{
    struct TreeNode_t *cur = root;
    gchar *string =  gtk_string_object_get_string(GTK_STRING_OBJECT(item));
    
    if (strcmp(string, "Child 1")) {
        cur = root->child;
    }
    else if (strcmp(string, "Child 2")) {
        cur = root->child->next;
    } else {
        cur = NULL;
    }

    return get_children_model(cur);
}

void setup_factory (GtkListItemFactory *factory, GtkListItem *list_item, gpointer user_data)
{
        GtkWidget *label = gtk_label_new(NULL);
        gtk_list_item_set_child(list_item, label);
}

void bind_factory (GtkListItemFactory *factory, GtkListItem *list_item, gpointer user_data)
{
        GObject *item = gtk_list_item_get_item(list_item);
        const gchar *text = gtk_string_object_get_string(GTK_STRING_OBJECT(item));
        GtkWidget *label = gtk_list_item_get_child(list_item);
        gtk_label_set_text(GTK_LABEL(label), text);
}

// Application activation callback
void app_activate (GApplication *app, gpointer user_data)
{
    GtkWidget *window = gtk_application_window_new(GTK_APPLICATION(app));
    gtk_window_set_title(GTK_WINDOW(window), "GTK4 Tree Example");
    gtk_window_set_default_size(GTK_WINDOW(window), 400, 300);

    GtkStringList *model = gtk_string_list_new(NULL);
    gtk_string_list_append(model, root->text);

    // Create a GtkTreeListModel
    GtkTreeListModel *tree_model = gtk_tree_list_model_new(
        G_LIST_MODEL(model),
        TRUE, // Passthrough - False in actual usage with dynamic children retrieval
        TRUE, // autoexpand
        (GtkTreeListModelCreateModelFunc)create_model_func,
        NULL,
        NULL  //(GDestroyNotify)free_tree_node
    );

    // Create and setup the list view and item factory
    GtkListItemFactory *factory = gtk_signal_list_item_factory_new();
    g_signal_connect(factory, "setup", G_CALLBACK(setup_factory), NULL);
    g_signal_connect(factory, "bind", G_CALLBACK(bind_factory), NULL);

    GtkWidget *list_view = gtk_list_view_new(GTK_SELECTION_MODEL(gtk_no_selection_new(tree_model)), factory);

    gtk_window_set_child(GTK_WINDOW(window), list_view);
    gtk_widget_set_visible(window, TRUE);
}

int main (int argc, char **argv)
{
    // Create a simple tree structure
    root = create_tree_node("Root");
    add_child_node(root, create_tree_node("Child 1"));
    add_child_node(root, create_tree_node("Child 2"));
    GtkApplication *app = gtk_application_new("org.gtk.example", G_APPLICATION_FLAGS_NONE);
    g_signal_connect(app, "activate", G_CALLBACK(app_activate), NULL);
    int status = g_application_run(G_APPLICATION(app), argc, argv);
    g_object_unref(app);
    free_tree_node(root); // Ensure to free the tree structure after the app has finished
    return status;
}