sedona_editor/main.py

"""Sedona SAX Tree View Viewer & Program Editor — UI wiring, dialogs and event handlers."""

import os
import sys
import tkinter as tk
from tkinter import filedialog, font as tkfont, messagebox, ttk

import app_state
import manage_kits
import palette
import sax_file
import schema
import undo
import wiresheet
from sax_dom import get_component_path, read_meta_property, update_meta_property

# Tree column measurements, in pixels. The padding covers the expander arrow and the
# cell's own inset, which sit ahead of the text ttk lets us measure.
TREE_INDENT = 20
TREE_TEXT_PADDING = 28
TREE_MIN_COLUMN_WIDTH = 40

# Rows each list asks for. This is the only real floor ttk offers on the left column's own
# split: a pane keeps its requested height, and a short window takes the shortfall from the
# panes in proportion to their weights. Left at the ten-row default the palette asked for
# so much that the tree, carrying the larger weight, gave up all of its height first.
TREE_REQUESTED_ROWS = 6
PALETTE_REQUESTED_ROWS = 5

# Below this the shortfall is deep enough to shrink the tree past a usable few rows, and
# ttk has no way to hold a pane at a floor once the room is simply not there.
MIN_WINDOW_HEIGHT = 300


def refresh_all_views():
    """Rebuilds tree and canvas from the DOM. Registered as undo/redo's view refresh."""
    sax_file.refresh_treeview_from_dom(app_state.xml_root_element)
    wiresheet.render_current_sheet()


def do_undo(event=None):
    label = undo.undo()
    if label is None:
        return "break"
    app_state.window.title(f"{app_state.base_window_title()} — undid {label}")
    return "break"


def do_redo(event=None):
    label = undo.redo()
    if label is None:
        return "break"
    app_state.window.title(f"{app_state.base_window_title()} — redid {label}")
    return "break"


def do_save(event=None):
    sax_file.execute_direct_overwrite_save()
    return "break"


NL = chr(10)   # newline, for the multi-line message boxes


def do_tidy_layout(event=None):
    """Menu command: re-flow the open sheet so nothing overlaps."""
    if not app_state.canvas_comp_map:
        messagebox.showinfo("Tidy Layout", "Open a sheet with components first.")
        return "break"

    moved, clamped = wiresheet.tidy_layout()
    multiplier = app_state.meta_scale // app_state.GRID_SIZE

    if moved == 0:
        messagebox.showinfo("Tidy Layout", "Nothing to move — no boxes overlap.")
    elif clamped:
        messagebox.showwarning(
            "Tidy Layout",
            f"Repositioned {moved} component(s).\n\n"
            f"{clamped} still hit the coordinate limit of {wiresheet.META_COORD_MAX} "
            "steps, because meta stores x and y in one byte each. This sheet is already "
            f"laid out at {multiplier} grid squares per step, the widest meta can reach, "
            "so it does not fit however it is spaced. Split it across sub-sheets."
        )
    elif multiplier > 1:
        messagebox.showinfo(
            "Tidy Layout",
            f"Repositioned {moved} component(s)." + NL + NL +
            f"This sheet needs more width than meta's {wiresheet.META_COORD_MAX} "
            f"coordinate steps allow at one grid square each, so it is laid out at "
            f"{multiplier} grid squares per step ({app_state.meta_scale} px). Boxes "
            f"settle on every {multiplier} grid lines rather than every one. Your grid "
            "size in Preferences is unchanged."
        )
    return "break"


# --- Event handlers ---

def on_tree_select(event):
    """Triggered when a branch node is clicked in the Navigation view."""
    tree = app_state.tree
    selected_items = tree.selection()
    if not selected_items:
        return

    selected_id = selected_items[0]
    element = app_state.tree_element_map.get(selected_id)
    components_to_render = []

    # Remembered so undo/redo and tidy can repaint this same sheet from the DOM.
    app_state.current_sheet_parent = element

    if element is not None:
        components_to_render = [child for child in element if child.tag == "comp"]
    else:
        top_level_ids = tree.get_children(selected_id)
        for t_id in top_level_ids:
            comp_elem = app_state.tree_element_map.get(t_id)
            if comp_elem is not None:
                components_to_render.append(comp_elem)

    wiresheet.render_components(components_to_render)


def delete_selected_link():
    """Removes the currently selected link from the DOM and repaints."""
    if not app_state.selected_link_tag:
        return
    link_elem = app_state.canvas_link_map.get(app_state.selected_link_tag)
    if link_elem is None:
        return

    from_ref = link_elem.get("from", "")
    to_ref = link_elem.get("to", "")
    confirm = messagebox.askyesno(
        "Delete Link",
        f"Delete link?\n\n  from: {from_ref}\n  to:     {to_ref}"
    )
    if not confirm:
        return

    sax_file.remove_link(link_elem)


def delete_selected_component(event=None):
    """Deletes the highlighted canvas component (or selected link) and all its descendants recursively."""
    if app_state.selected_link_tag:
        delete_selected_link()
        return

    if not app_state.selected_canvas_tag:
        return

    comp_element = app_state.canvas_comp_map.get(app_state.selected_canvas_tag)
    if comp_element is not None:
        sax_file.execute_cascading_deletion(comp_element)


def delete_tree_selected_component():
    """Triggered by the context popup menu to delete an item selected in the Treeview architecture."""
    if not app_state.selected_tree_item_id:
        return

    comp_element = app_state.tree_element_map.get(app_state.selected_tree_item_id)
    if comp_element is not None:
        sax_file.execute_cascading_deletion(comp_element)


def on_tree_right_click(event):
    """Intercepts right-clicks on the treeview architecture to render branch context panels."""
    tree = app_state.tree
    item_id = tree.identify_row(event.y)
    if not item_id:
        return

    tree.selection_set(item_id)
    app_state.selected_tree_item_id = item_id
    parent_id = tree.parent(item_id)

    if parent_id == "":
        tree_root_context_menu.post(event.x_root, event.y_root)
    else:
        tree_comp_context_menu.post(event.x_root, event.y_root)


def on_canvas_click(event):
    canvas = app_state.canvas
    canvas.itemconfig("block_outline", outline="#7f9db9", width=2)
    wiresheet.deselect_link()
    app_state.drag_data["tag"] = None
    app_state.selected_canvas_tag = None

    cx = canvas.canvasx(event.x)
    cy = canvas.canvasy(event.y)
    clicked_item = canvas.find_closest(cx, cy, halo=3)

    if not clicked_item:
        return

    tags = canvas.gettags(clicked_item[0])
    group_tag = next((t for t in tags if t.startswith("comp_group_")), None)
    wire_tag = next((t for t in tags if t.startswith("link_wire_")), None)

    if wire_tag:
        wiresheet.select_link(wire_tag)
        return

    if group_tag:
        app_state.drag_data["tag"] = group_tag
        app_state.drag_data["x"] = cx
        app_state.drag_data["y"] = cy
        app_state.selected_canvas_tag = group_tag

        # Where the box starts out. The drag is measured as an offset from this pair
        # rather than accumulated per motion event, so repeated snapping cannot drift.
        origin = wiresheet.get_box_origin(group_tag)
        app_state.drag_data["box_x"] = origin[0] if origin else None
        app_state.drag_data["box_y"] = origin[1] if origin else None

        # Snapshot the pre-drag meta so the move can be pushed as one undoable step.
        dragged = app_state.canvas_comp_map.get(group_tag)
        meta_prop = dragged.find("prop[@name='meta']") if dragged is not None else None
        app_state.drag_data["meta_before"] = meta_prop.get("val") if meta_prop is not None else None
        canvas.itemconfig(f"{group_tag} && block_outline", outline="#1f4e79", width=3)

        # Bring the clicked box clear of any neighbour it happens to sit under.
        canvas.tag_raise(group_tag)
        wiresheet.draw_links()


def do_link_mark():
    """Marks the currently selected canvas component as a link endpoint."""
    if not app_state.selected_canvas_tag:
        return
    comp = app_state.canvas_comp_map.get(app_state.selected_canvas_tag)
    if comp is not None:
        app_state.link_mark_element = comp


def _slot_linkable(slot_flags, slot_type, readonly, is_target):
    """Returns False if a slot cannot participate in a link on the given side."""
    if is_target and readonly:
        return False
    if "a" in slot_flags or slot_type == "void":
        return False
    return True


def open_link_dialog(source_element, target_element):
    """Opens a dialog to select source and target slots, validates types, and creates a link."""
    window = app_state.window

    sides = [source_element, target_element]

    dialog = tk.Toplevel(window)
    dialog.title("Link")
    dialog.resizable(False, False)
    dialog.transient(window)
    dialog.grab_set()
    dialog.geometry(f"+{window.winfo_x() + 100}+{window.winfo_y() + 60}")

    main_frame = tk.Frame(dialog, padx=10, pady=10)
    main_frame.pack(fill=tk.BOTH, expand=True)

    src_frame = tk.LabelFrame(main_frame, padx=5, pady=5)
    src_frame.grid(row=0, column=0, sticky="nsew", padx=(0, 5))

    mid_frame = tk.Frame(main_frame)
    mid_frame.grid(row=0, column=1, padx=5)

    tgt_frame = tk.LabelFrame(main_frame, padx=5, pady=5)
    tgt_frame.grid(row=0, column=2, sticky="nsew", padx=(5, 0))

    src_var = tk.StringVar(value="")
    tgt_var = tk.StringVar(value="")

    src_widgets = []
    tgt_widgets = []
    src_slot_info = {}
    tgt_slot_info = {}

    status_var = tk.StringVar(value="")

    def _update_peer_states(selected_var, selected_info, peer_widgets, peer_info, peer_is_target):
        """Grey out incompatible slots on the peer side after a selection."""
        chosen = selected_var.get()
        if not chosen or chosen not in selected_info:
            for rb in peer_widgets:
                name = rb.cget("value")
                info = peer_info.get(name)
                if info and _slot_linkable(info[1], info[0], info[2], peer_is_target):
                    rb.config(state=tk.NORMAL, fg="black")
                else:
                    rb.config(state=tk.DISABLED, fg="#999999")
            return

        sel_type = selected_info[chosen][0]

        for rb in peer_widgets:
            name = rb.cget("value")
            info = peer_info.get(name)
            if not info:
                rb.config(state=tk.DISABLED, fg="#999999")
                continue

            peer_type, peer_flags, peer_ro = info
            if not _slot_linkable(peer_flags, peer_type, peer_ro, peer_is_target):
                rb.config(state=tk.DISABLED, fg="#999999")
            elif peer_type != sel_type:
                rb.config(state=tk.DISABLED, fg="#999999")
            else:
                rb.config(state=tk.NORMAL, fg="black")

    def _on_src_change(*_args):
        _update_peer_states(src_var, src_slot_info, tgt_widgets, tgt_slot_info, True)
        _update_status_label()

    def _on_tgt_change(*_args):
        _update_peer_states(tgt_var, tgt_slot_info, src_widgets, src_slot_info, False)
        _update_status_label()

    def _update_status_label():
        s = src_var.get()
        t = tgt_var.get()
        left_name = sides[0].get("name", "?")
        right_name = sides[1].get("name", "?")
        if s and t:
            status_var.set(f"Link {left_name}.{s} -> {right_name}.{t}")
        elif s:
            status_var.set(f"Link {left_name}.{s} -> ?")
        elif t:
            status_var.set(f"Link ? -> {right_name}.{t}")
        else:
            status_var.set("")

    def populate_panel(parent_frame, slots, var, widgets_list, info_dict, is_target):
        for child in parent_frame.winfo_children():
            child.destroy()
        widgets_list.clear()
        info_dict.clear()

        panel_canvas = tk.Canvas(parent_frame, width=160, height=300, highlightthickness=0)
        panel_scroll = ttk.Scrollbar(parent_frame, orient=tk.VERTICAL, command=panel_canvas.yview)
        inner = tk.Frame(panel_canvas)
        panel_canvas.create_window((0, 0), window=inner, anchor="nw")
        panel_canvas.config(yscrollcommand=panel_scroll.set)
        panel_canvas.pack(side=tk.LEFT, fill=tk.BOTH, expand=True)
        panel_scroll.pack(side=tk.RIGHT, fill=tk.Y)

        for slot_name, slot_type, slot_flags, slot_ro in slots:
            info_dict[slot_name] = (slot_type, slot_flags, slot_ro)
            linkable = _slot_linkable(slot_flags, slot_type, slot_ro, is_target)
            rb = tk.Radiobutton(inner, text=slot_name, variable=var, value=slot_name,
                                anchor="w", bg="#c8d4e8", relief="flat", padx=4, pady=1,
                                state=tk.NORMAL if linkable else tk.DISABLED,
                                fg="black" if linkable else "#999999",
                                disabledforeground="#999999")
            rb.pack(fill=tk.X)
            widgets_list.append(rb)

        inner.update_idletasks()
        panel_canvas.config(scrollregion=panel_canvas.bbox("all"))

    def refresh_panels():
        left = sides[0]
        right = sides[1]
        left_name = left.get("name", "?")
        right_name = right.get("name", "?")
        left_type = left.get("type", "")
        right_type = right.get("type", "")

        src_frame.config(text=f"{left_name} [Source]")
        tgt_frame.config(text=f"{right_name} [Target]")

        left_slots = schema.get_all_slots_for_type(left_type)
        right_slots = schema.get_all_slots_for_type(right_type)

        src_var.set("")
        tgt_var.set("")
        populate_panel(src_frame, left_slots, src_var, src_widgets, src_slot_info, False)
        populate_panel(tgt_frame, right_slots, tgt_var, tgt_widgets, tgt_slot_info, True)
        _update_status_label()

    src_var.trace_add("write", _on_src_change)
    tgt_var.trace_add("write", _on_tgt_change)

    def on_swap():
        sides[0], sides[1] = sides[1], sides[0]
        refresh_panels()

    ttk.Button(mid_frame, text="⇄", width=3, command=on_swap).pack(pady=5)

    refresh_panels()

    status_label = tk.Label(main_frame, textvariable=status_var, anchor="w", fg="#333333")
    status_label.grid(row=1, column=0, columnspan=3, sticky="w", pady=(8, 0))

    def on_ok():
        src_slot = src_var.get()
        tgt_slot = tgt_var.get()

        if not src_slot or not tgt_slot:
            messagebox.showwarning("Link", "Select a slot from both source and target.", parent=dialog)
            return

        st = src_slot_info.get(src_slot, ("?", ""))[0]
        tt = tgt_slot_info.get(tgt_slot, ("?", ""))[0]

        if st != tt:
            messagebox.showwarning(
                "Slot type mismatch",
                f"Cannot link slots of different types.\n\n"
                f"Source: {src_slot} ({st})\n"
                f"Target: {tgt_slot} ({tt})",
                parent=dialog
            )
            return

        src_path = get_component_path(sides[0], app_state.xml_root_element)
        tgt_path = get_component_path(sides[1], app_state.xml_root_element)

        from_ref = f"{src_path}.{src_slot}"
        to_ref = f"{tgt_path}.{tgt_slot}"

        dialog.destroy()
        sax_file.add_link(from_ref, to_ref)

    btn_frame = tk.Frame(main_frame)
    btn_frame.grid(row=2, column=0, columnspan=3, pady=(15, 0))

    ttk.Button(btn_frame, text="OK", width=10, command=on_ok).pack(side=tk.LEFT, padx=5)
    ttk.Button(btn_frame, text="Cancel", width=10, command=dialog.destroy).pack(side=tk.LEFT, padx=5)


def do_link_from_mark():
    """Link From: marked component is source, right-clicked component is target."""
    if app_state.link_mark_element is None or not app_state.selected_canvas_tag:
        return
    target = app_state.canvas_comp_map.get(app_state.selected_canvas_tag)
    if target is not None:
        open_link_dialog(app_state.link_mark_element, target)


def do_link_to_mark():
    """Link To: right-clicked component is source, marked component is target."""
    if app_state.link_mark_element is None or not app_state.selected_canvas_tag:
        return
    source = app_state.canvas_comp_map.get(app_state.selected_canvas_tag)
    if source is not None:
        open_link_dialog(source, app_state.link_mark_element)


def on_canvas_right_click(event):
    """Detects right-clicks on nodes to instantly show context-sensitive action overlays."""
    canvas = app_state.canvas
    cx = canvas.canvasx(event.x)
    cy = canvas.canvasy(event.y)
    clicked_item = canvas.find_closest(cx, cy, halo=3)

    if clicked_item:
        tags = canvas.gettags(clicked_item[0])
        group_tag = next((t for t in tags if t.startswith("comp_group_")), None)
        wire_tag = next((t for t in tags if t.startswith("link_wire_")), None)

        if wire_tag:
            wiresheet.select_link(wire_tag)
            link_context_menu.post(event.x_root, event.y_root)
            return

        if group_tag:
            wiresheet.deselect_link()
            canvas.itemconfig("block_outline", outline="#7f9db9", width=2)
            app_state.selected_canvas_tag = group_tag
            canvas.itemconfig(f"{group_tag} && block_outline", outline="#1f4e79", width=3)

            _rebuild_canvas_context_menu()
            canvas_context_menu.post(event.x_root, event.y_root)


def on_canvas_drag(event):
    if not app_state.drag_data["tag"]:
        return

    canvas = app_state.canvas
    group_tag = app_state.drag_data["tag"]
    cx = canvas.canvasx(event.x)
    cy = canvas.canvasy(event.y)

    box_x = app_state.drag_data.get("box_x")
    origin = wiresheet.get_box_origin(group_tag)

    if box_x is None or origin is None:
        # Nothing to align against, so the box just follows the pointer one to one.
        canvas.move(group_tag, cx - app_state.drag_data["x"], cy - app_state.drag_data["y"])
        app_state.drag_data["x"] = cx
        app_state.drag_data["y"] = cy
        wiresheet.draw_links()
        return

    # Snap to whole meta steps, which is the grid on an ordinary sheet and a multiple of
    # it on one too wide for meta's range -- a position between steps cannot be stored.
    step = app_state.meta_scale
    margin = wiresheet.layout_margin(step)

    # Follow the pointer, but land the box on a step every step of the way, and keep it
    # out of the margin strip along the top and left canvas edges.
    wanted_x = box_x + (cx - app_state.drag_data["x"])
    wanted_y = app_state.drag_data["box_y"] + (cy - app_state.drag_data["y"])
    target_x = max(margin, round(wanted_x / step) * step)
    target_y = max(margin, round(wanted_y / step) * step)

    shift_x = target_x - origin[0]
    shift_y = target_y - origin[1]

    if shift_x or shift_y:
        canvas.move(group_tag, shift_x, shift_y)
        # Wires are not part of the dragged group, so they are re-routed against the
        # new positions.
        wiresheet.draw_links()


def on_canvas_release(event):
    if not app_state.drag_data["tag"]:
        return

    canvas = app_state.canvas
    step = app_state.meta_scale
    group_tag = app_state.drag_data["tag"]
    origin = wiresheet.get_box_origin(group_tag)

    if origin is not None:
        current_x, current_y = origin

        margin = wiresheet.layout_margin(step)
        snapped_x = max(margin, round(current_x / step) * step)
        snapped_y = max(margin, round(current_y / step) * step)

        shift_x = snapped_x - current_x
        shift_y = snapped_y - current_y

        if shift_x != 0 or shift_y != 0:
            canvas.move(group_tag, shift_x, shift_y)
            app_state.mark_dirty()

        raw_x = min(wiresheet.META_COORD_MAX, int(round(snapped_x / step)))
        raw_y = min(wiresheet.META_COORD_MAX, int(round(snapped_y / step)))

        comp_element = app_state.canvas_comp_map.get(group_tag)
        if comp_element is not None:
            meta_str = None
            orig_prop = comp_element.find("prop[@name='meta']")
            if orig_prop is not None:
                meta_str = orig_prop.get("val")

            orig_x, orig_y, _, _, _, _, _, _ = read_meta_property(meta_str)
            if orig_x != raw_x or orig_y != raw_y:
                meta_before = app_state.drag_data.get("meta_before", meta_str)
                update_meta_property(comp_element, meta_str, raw_x, raw_y)
                undo.push(undo.MetaMoveCommand(
                    [(comp_element, meta_before, raw_x, raw_y)],
                    label=f"move {comp_element.get('name', 'component')}"
                ))
                app_state.mark_dirty()

    app_state.drag_data["tag"] = None
    wiresheet.draw_links()


def fit_tree_column(tree):
    """Sizes a Treeview's tree column to its widest visible row.

    ttk derives the horizontal scroll range from the column width, so a column left to
    stretch with the widget can never scroll - long text is simply clipped. Sizing it to
    the content is what gives the horizontal scrollbar something to move, and the max()
    keeps a short list filling the width it has instead of leaving a bare strip.
    """
    if tree is None or not tree.winfo_exists():
        return

    style = ttk.Style()
    text_font = tkfont.nametofont(style.lookup("Treeview", "font") or "TkDefaultFont")
    try:
        indent = int(style.lookup("Treeview", "indent") or TREE_INDENT)
    except (ValueError, tk.TclError):
        indent = TREE_INDENT

    widest = 0

    def measure(node, depth):
        nonlocal widest
        for child in tree.get_children(node):
            width = depth * indent + text_font.measure(tree.item(child, "text"))
            widest = max(widest, width)
            # A closed branch hides its children, so they are not part of the width.
            if tree.item(child, "open"):
                measure(child, depth + 1)

    measure("", 1)
    tree.column("#0", width=max(widest + TREE_TEXT_PADDING, tree.winfo_width() - 2),
                minwidth=TREE_MIN_COLUMN_WIDTH, stretch=False)


def attach_tree_scrollbars(container, tree):
    """Puts a Treeview in its container with scrollbars that show only when they help.

    The tree/palette column is a fixed width now, so a deep path or a long type name has
    to be reachable by scrolling sideways rather than by widening the window. A bar that
    has nothing to scroll is taken out of the grid so it costs no room.
    """
    vertical = ttk.Scrollbar(container, orient=tk.VERTICAL, command=tree.yview)
    horizontal = ttk.Scrollbar(container, orient=tk.HORIZONTAL, command=tree.xview)
    vertical_cell = {"row": 0, "column": 1, "sticky": "ns"}
    horizontal_cell = {"row": 1, "column": 0, "sticky": "ew"}

    def show_when_needed(bar, cell, first, last):
        if float(first) <= 0.0 and float(last) >= 1.0:
            bar.grid_remove()
        else:
            bar.grid(**cell)
        bar.set(first, last)

    tree.configure(
        yscrollcommand=lambda first, last: show_when_needed(vertical, vertical_cell, first, last),
        xscrollcommand=lambda first, last: show_when_needed(horizontal, horizontal_cell, first, last),
    )

    container.rowconfigure(0, weight=1)
    container.columnconfigure(0, weight=1)
    tree.grid(row=0, column=0, sticky="nsew")

    # Resizing, and opening or closing a branch, both change what the widest row is.
    tree.bind("<Configure>", lambda event: fit_tree_column(tree), add="+")
    tree.bind("<<TreeviewOpen>>", lambda event: tree.after_idle(fit_tree_column, tree), add="+")
    tree.bind("<<TreeviewClose>>", lambda event: tree.after_idle(fit_tree_column, tree), add="+")


def clamp_left_pane_split(event=None):
    """Keeps both halves of the left column visible, whatever the sash or the window does.

    ttk lets a sash drag run to either end, and it remembers that position when the window
    is made shorter afterwards, so either list can be left with no height at all. Each
    pane's requested height is the line. Once the column is too short to seat both, the
    floors are dropped and ttk's own proportional squeeze takes over.
    """
    total = left_pane.winfo_height()
    tree_floor = frame_tree.winfo_reqheight()
    palette_floor = frame_palette.winfo_reqheight()
    if total <= tree_floor + palette_floor:
        return

    position = left_pane.sashpos(0)
    clamped = min(max(position, tree_floor), total - palette_floor)
    if clamped != position:
        left_pane.sashpos(0, clamped)


def apply_left_pane_width():
    """Pins the tree/palette column to the configured width.

    Setting the sash before the paned window has been laid out collapses the column
    instead of sizing it, so the startup call retries until there is a width to divide.
    This is also how a changed preference reaches an already open window.
    """
    app_state.window.update_idletasks()
    if paned_window.winfo_width() <= 1:
        paned_window.after(50, apply_left_pane_width)
        return
    paned_window.sashpos(0, app_state.LEFT_PANE_WIDTH)


# --- Dialogs ---

def open_preferences_dialog():
    """Pops open a tabular modal dialog to edit configuration attributes."""
    window = app_state.window

    dialog = tk.Toplevel(window)
    dialog.title("Preferences")
    dialog.geometry("470x290")
    dialog.resizable(False, False)
    dialog.transient(window)
    dialog.grab_set()

    dialog.geometry(f"+{window.winfo_x() + 100}+{window.winfo_y() + 100}")

    frame_padded = ttk.Frame(dialog, padding=15)
    frame_padded.pack(fill=tk.BOTH, expand=True)

    frame_padded.columnconfigure(0, weight=1, minsize=160)
    frame_padded.columnconfigure(1, weight=2)

    lbl_home = ttk.Label(frame_padded, text="Sedona home folder:", anchor="w")
    lbl_home.grid(row=0, column=0, sticky="w", pady=(0, 10), padx=(0, 10))

    frame_home_picker = ttk.Frame(frame_padded)
    frame_home_picker.grid(row=0, column=1, sticky="ew", pady=(0, 10))
    frame_home_picker.columnconfigure(0, weight=1)

    entry_home = ttk.Entry(frame_home_picker)
    entry_home.insert(0, app_state.SEDONA_HOME)
    entry_home.grid(row=0, column=0, sticky="ew", padx=(0, 5))

    def browse_home_folder():
        chosen_dir = filedialog.askdirectory(title="Select Sedona Home Folder", initialdir=entry_home.get() or None)
        if chosen_dir:
            entry_home.delete(0, tk.END)
            entry_home.insert(0, os.path.normpath(chosen_dir))

    btn_home_browse = ttk.Button(frame_home_picker, text="...", width=3, command=browse_home_folder)
    btn_home_browse.grid(row=0, column=1, sticky="e")

    lbl_size = ttk.Label(frame_padded, text="Grid size (pixels):", anchor="w")
    lbl_size.grid(row=1, column=0, sticky="w", pady=(0, 10), padx=(0, 10))

    entry_grid = ttk.Entry(frame_padded)
    entry_grid.insert(0, str(app_state.GRID_SIZE))
    entry_grid.grid(row=1, column=1, sticky="ew", pady=(0, 10))

    lbl_box = ttk.Label(frame_padded, text="Component box width (pixels):", anchor="w")
    lbl_box.grid(row=2, column=0, sticky="w", pady=(0, 10), padx=(0, 10))

    entry_box_width = ttk.Entry(frame_padded)
    entry_box_width.insert(0, str(app_state.BOX_WIDTH))
    entry_box_width.grid(row=2, column=1, sticky="ew", pady=(0, 10))

    lbl_left_pane = ttk.Label(frame_padded, text="Tree/palette width (pixels):", anchor="w")
    lbl_left_pane.grid(row=3, column=0, sticky="w", pady=(0, 10), padx=(0, 10))

    entry_left_pane = ttk.Entry(frame_padded)
    entry_left_pane.insert(0, str(app_state.LEFT_PANE_WIDTH))
    entry_left_pane.grid(row=3, column=1, sticky="ew", pady=(0, 10))

    lbl_timestamp = ttk.Label(frame_padded, text="Save with Date-Time stamp?", anchor="w")
    lbl_timestamp.grid(row=4, column=0, sticky="w", pady=(0, 15), padx=(0, 10))

    var_timestamp = tk.BooleanVar(value=app_state.ADD_TIMESTAMP)
    chk_timestamp = ttk.Checkbutton(
        frame_padded,
        text="Yes",
        variable=var_timestamp
    )
    chk_timestamp.grid(row=4, column=1, sticky="w", pady=(0, 15))

    def apply_preferences():
        try:
            val = int(entry_grid.get().strip())
            if val < 2 or val > 200:
                raise ValueError("Grid size must be a whole number between 2 and 200.")

            try:
                width = int(entry_box_width.get().strip())
            except ValueError:
                raise ValueError(
                    f"Box width must be a whole number between "
                    f"{app_state.MIN_ALLOWED_BOX_WIDTH} and {app_state.MAX_ALLOWED_BOX_WIDTH}."
                )
            if not (app_state.MIN_ALLOWED_BOX_WIDTH <= width <= app_state.MAX_ALLOWED_BOX_WIDTH):
                raise ValueError(
                    f"Box width must be between {app_state.MIN_ALLOWED_BOX_WIDTH} and "
                    f"{app_state.MAX_ALLOWED_BOX_WIDTH} pixels."
                )

            try:
                pane_width = int(entry_left_pane.get().strip())
            except ValueError:
                raise ValueError(
                    f"Tree/palette width must be a whole number between "
                    f"{app_state.MIN_ALLOWED_LEFT_PANE_WIDTH} and "
                    f"{app_state.MAX_ALLOWED_LEFT_PANE_WIDTH}."
                )
            if not (app_state.MIN_ALLOWED_LEFT_PANE_WIDTH <= pane_width
                    <= app_state.MAX_ALLOWED_LEFT_PANE_WIDTH):
                raise ValueError(
                    f"Tree/palette width must be between "
                    f"{app_state.MIN_ALLOWED_LEFT_PANE_WIDTH} and "
                    f"{app_state.MAX_ALLOWED_LEFT_PANE_WIDTH} pixels."
                )

            # The width cap is applied after each box is fitted to its text, so a cap
            # that is not a multiple of the grid leaves the widest boxes off-grid.
            proposed = wiresheet.suggest_box_width_for_grid(width, val)
            if proposed != width:
                if not messagebox.askyesno(
                    "Box Width Off Grid",
                    f"A box width of {width} px is not a multiple of the {val} px grid, "
                    f"so the widest boxes would not line up with it.\n\n"
                    f"Change the box width to {proposed} px?",
                    parent=dialog,
                ):
                    return
                width = proposed
                entry_box_width.delete(0, tk.END)
                entry_box_width.insert(0, str(width))

            app_state.BOX_WIDTH = width
            app_state.LEFT_PANE_WIDTH = pane_width
            app_state.GRID_SIZE = val
            app_state.ADD_TIMESTAMP = var_timestamp.get()
            app_state.SEDONA_HOME = entry_home.get().strip()

            app_state.save_preferences()

            apply_left_pane_width()
            wiresheet.draw_grid()
            if app_state.active_components_list:
                wiresheet.render_components(app_state.active_components_list)

            # Sedona home may have moved, so the palette's kit list is rebuilt.
            refresh_palette_kits()

            dialog.destroy()
        except ValueError as error:
            message = str(error) or "Please enter a valid integer size between 2 and 200."
            messagebox.showerror("Invalid Input", message, parent=dialog)

    btn_save_pref = ttk.Button(frame_padded, text="Apply Changes", command=apply_preferences)
    btn_save_pref.grid(row=5, column=1, sticky="e")

    if not app_state.SEDONA_HOME:
        entry_home.focus_set()
    else:
        entry_grid.focus_set()


def show_app_info():
    """Displays information tracking details for the currently active schema file in standard columns."""
    window = app_state.window

    if app_state.current_file_path:
        file_name = os.path.basename(app_state.current_file_path)
        folder_path = os.path.dirname(app_state.current_file_path)
    else:
        file_name = "No profile loaded"
        folder_path = "None"

    lastReachedID = 0
    all_found_ids = set()

    if app_state.xml_root_element is not None:
        for elem in app_state.xml_root_element.iter():
            if elem.tag == "comp":
                id_str = elem.get("id")
                if id_str is not None:
                    try:
                        val = int(id_str)
                        all_found_ids.add(val)
                        if val > lastReachedID:
                            lastReachedID = val
                    except ValueError:
                        pass

    not_used_ids = [i for i in range(1, lastReachedID + 1) if i not in all_found_ids]
    usedComponentNumber = lastReachedID - len(not_used_ids)

    not_used_str = ", ".join(map(str, not_used_ids)) if not_used_ids else "None"
    if len(not_used_str) > 40:
        not_used_str = not_used_str[:37] + "..."

    info_win = tk.Toplevel(window)
    info_win.title("App Info")
    info_win.resizable(False, False)
    info_win.transient(window)
    info_win.grab_set()

    frame = ttk.Frame(info_win, padding=15)
    frame.pack(fill=tk.BOTH, expand=True)

    rows_data = [
        ("App File Name:", file_name),
        ("File Location:", folder_path),
        ("Last Reached ID:", str(lastReachedID)),
        ("Used Component Count:", str(max(0, usedComponentNumber))),
        ("Unused IDs:", not_used_str)
    ]

    for idx, (lbl_txt, val_txt) in enumerate(rows_data):
        lbl = tk.Label(frame, text=lbl_txt, font=("TkDefaultFont", 9, "bold"), anchor="w")
        lbl.grid(row=idx, column=0, sticky="w", padx=(0, 15), pady=4)

        val = tk.Label(frame, text=val_txt, anchor="w", justify="left")
        val.grid(row=idx, column=1, sticky="w", pady=4)

    info_win.update_idletasks()
    x = window.winfo_x() + (window.winfo_width() // 2) - (info_win.winfo_width() // 2)
    y = window.winfo_y() + (window.winfo_height() // 2) - (info_win.winfo_height() // 2)
    info_win.geometry(f"+{x}+{y}")


def verify_startup_configurations():
    """Checks for configuration gaps, triggers an alert, and opens setup if empty."""
    if not app_state.SEDONA_HOME:
        messagebox.showwarning(
            "Configuration Required",
            "The 'Sedona home folder' path is not configured.\n\n"
            "Please specify the directory path in the configuration options "
            "before trying to view or load profile source files."
        )
        open_preferences_dialog()
        return

    # editor.properties can be hand-edited, so the pair is reconciled here too.
    proposed = wiresheet.suggest_box_width_for_grid(app_state.BOX_WIDTH, app_state.GRID_SIZE)
    if proposed != app_state.BOX_WIDTH and messagebox.askyesno(
        "Box Width Off Grid",
        f"The saved box width of {app_state.BOX_WIDTH} px is not a multiple of the "
        f"{app_state.GRID_SIZE} px grid, so the widest boxes will not line up with it.\n\n"
        f"Change the box width to {proposed} px?",
    ):
        app_state.BOX_WIDTH = proposed
        app_state.save_preferences()
        wiresheet.draw_grid()
        if app_state.active_components_list:
            wiresheet.render_components(app_state.active_components_list)


# --- UI Setup ---
window = tk.Tk()
app_state.window = window
window.title(app_state.base_window_title())
window.geometry("950x600")
# Width is left alone; only the height needs a floor, to keep the tree pane off zero.
window.minsize(1, MIN_WINDOW_HEIGHT)

# --- Context Popups Structures ---
canvas_context_menu = tk.Menu(window, tearoff=0)
link_context_menu = tk.Menu(window, tearoff=0)
link_context_menu.add_command(label="Delete Link", command=delete_selected_link)


def _rebuild_canvas_context_menu():
    """Rebuilds the canvas context menu with dynamic Link From/Link To labels."""
    canvas_context_menu.delete(0, tk.END)
    canvas_context_menu.add_command(label="Delete Component", command=delete_selected_component)
    canvas_context_menu.add_separator()
    canvas_context_menu.add_command(label="Link Mark", command=do_link_mark)

    if app_state.link_mark_element is not None:
        mark_name = app_state.link_mark_element.get("name", "?")
        canvas_context_menu.add_command(
            label=f'Link From "{mark_name}"', command=do_link_from_mark
        )
        canvas_context_menu.add_command(
            label=f'Link To "{mark_name}"', command=do_link_to_mark
        )

tree_comp_context_menu = tk.Menu(window, tearoff=0)
tree_comp_context_menu.add_command(label="Delete Component", command=delete_tree_selected_component)

tree_root_context_menu = tk.Menu(window, tearoff=0)
tree_root_context_menu.add_command(label="Save", command=sax_file.execute_direct_overwrite_save)

# --- Keyboard shortcuts ---
# Command and Control are both bound on every platform, so muscle memory from either
# side works and Windows users are not asked to learn a Mac chord.
SHORTCUTS = [
    ("s", do_save),
    ("z", do_undo),
    ("y", do_redo),
]
for key, handler in SHORTCUTS:
    window.bind_all(f"<Command-{key}>", handler)
    window.bind_all(f"<Control-{key}>", handler)

# Redo also as Shift-Z, the usual mac chord.
window.bind_all("<Command-Shift-Z>", do_redo)
window.bind_all("<Control-Shift-Z>", do_redo)

# Delete: the mac Delete key reports as BackSpace, the Windows one as Delete.
window.bind_all("<Delete>", delete_selected_component)
window.bind_all("<BackSpace>", delete_selected_component)

accel_mod = "Cmd" if sys.platform == "darwin" else "Ctrl"

# --- Native Application Menu Configurations ---
menu_bar = tk.Menu(window)

menu_file = tk.Menu(menu_bar, tearoff=0)
menu_file.add_command(label="Open", command=sax_file.open_file)
menu_file.add_command(label="Save", command=do_save, accelerator=f"{accel_mod}+S")
menu_file.add_command(label="Save As...", command=sax_file.save_file_as)
menu_file.add_separator()
menu_file.add_command(label="Exit", command=window.quit)
menu_bar.add_cascade(label="File", menu=menu_file)

menu_edit = tk.Menu(menu_bar, tearoff=0)
menu_edit.add_command(label="Undo", command=do_undo, accelerator=f"{accel_mod}+Z")
menu_edit.add_command(label="Redo", command=do_redo, accelerator=f"{accel_mod}+Y")
menu_edit.add_separator()
menu_edit.add_command(label="Delete Component", command=delete_selected_component, accelerator="Del")
menu_edit.add_separator()
menu_edit.add_command(label="Tidy Layout", command=do_tidy_layout)
menu_bar.add_cascade(label="Edit", menu=menu_edit)

menu_kits = tk.Menu(menu_bar, tearoff=0)
menu_kits.add_command(
    label="Manage Kits...",
    command=lambda: manage_kits.open_dialog(on_applied=refresh_palette_kits)
)
menu_bar.add_cascade(label="Kits", menu=menu_kits)

menu_app_info = tk.Menu(menu_bar, tearoff=0)
menu_app_info.add_command(label="App Info", command=show_app_info)
menu_bar.add_cascade(label="App", menu=menu_app_info)

menu_prefs = tk.Menu(menu_bar, tearoff=0)
menu_prefs.add_command(label="Preferences", command=open_preferences_dialog)
menu_bar.add_cascade(label="Preferences", menu=menu_prefs)

window.config(menu=menu_bar)

# Packed before the paned window: pack hands out the cavity in order, and the paned
# window expands into whatever is left, so a status bar added afterwards would get no room.
status_label = ttk.Label(window, text="", anchor="w", foreground=app_state.STATUS_INFO_COLOUR)
status_label.pack(side=tk.BOTTOM, fill=tk.X, padx=8, pady=(0, 4))
app_state.status_label = status_label

paned_window = ttk.PanedWindow(window, orient=tk.HORIZONTAL)
paned_window.pack(fill=tk.BOTH, expand=True, padx=5, pady=5)

# Left column splits into the navigation tree above and the component palette below.
left_pane = ttk.PanedWindow(paned_window, orient=tk.VERTICAL)

frame_tree = ttk.Frame(left_pane)

tree = ttk.Treeview(
    frame_tree,
    show="tree",
    selectmode="browse",
    height=TREE_REQUESTED_ROWS,
)
app_state.tree = tree
attach_tree_scrollbars(frame_tree, tree)
tree.bind("<<TreeviewSelect>>", on_tree_select)

tree.bind("<ButtonPress-3>", on_tree_right_click)
tree.bind("<ButtonPress-2>", on_tree_right_click)

left_pane.add(frame_tree, weight=3)

# --- Component palette ---
frame_palette = ttk.Frame(left_pane)

ttk.Label(frame_palette, text="Palette", font=("TkDefaultFont", 9, "bold")).pack(
    anchor="w", padx=4, pady=(4, 2)
)

palette_kit_var = tk.StringVar()
palette_kit_combo = ttk.Combobox(frame_palette, textvariable=palette_kit_var, state="readonly")
palette_kit_combo.pack(fill=tk.X, padx=4)

frame_palette_list = ttk.Frame(frame_palette)
frame_palette_list.pack(fill=tk.BOTH, expand=True, padx=4, pady=4)

palette_tree = ttk.Treeview(
    frame_palette_list,
    show="tree",
    selectmode="browse",
    height=PALETTE_REQUESTED_ROWS,
)
attach_tree_scrollbars(frame_palette_list, palette_tree)

palette_status = ttk.Label(frame_palette, text="", foreground="#666666")
palette_status.pack(anchor="w", padx=4, pady=(0, 4))


def populate_palette_types(event=None):
    """Lists the component types of the kit chosen in the palette dropdown."""
    for item in palette_tree.get_children():
        palette_tree.delete(item)

    index = palette_kit_combo.current()
    if index < 0 or index >= len(palette_kit_names):
        palette_status.config(text="")
        return

    kit_name = palette_kit_names[index]
    types = palette.list_component_types(kit_name)

    for type_name, base in types:
        palette_tree.insert("", "end", text=type_name, values=(f"{kit_name}::{type_name}", base))

    palette_status.config(text=f"{len(types)} component{'' if len(types) == 1 else 's'}")
    fit_tree_column(palette_tree)


def refresh_palette_kits():
    """Reloads the kit list from Sedona home. Also called after Preferences changes it."""
    global palette_kit_names

    palette.invalidate()
    palette_kit_names = palette.list_kits()

    labels = []
    for kit_name in palette_kit_names:
        version = palette.kit_version_label(kit_name)
        labels.append(f"{kit_name} ({version})" if version else kit_name)

    palette_kit_combo.config(values=labels)

    for item in palette_tree.get_children():
        palette_tree.delete(item)

    if not palette_kit_names:
        palette_status.config(
            text="No kits found — check Sedona home" if app_state.SEDONA_HOME
            else "Set Sedona home in Preferences"
        )
        palette_kit_var.set("")
        return

    palette_status.config(text=f"{len(palette_kit_names)} kits")
    palette_kit_var.set("")
    fit_tree_column(palette_tree)



# --- Palette drag and drop ---
# Tk has no drag-and-drop between widgets, so the gesture is assembled by hand:
# remember what was pressed, start dragging past a small threshold, follow the pointer
# with a borderless ghost window, and on release test the pointer against the canvas.
DRAG_THRESHOLD = 6

palette_drag = {"kit": None, "type": None, "origin": None, "active": False, "ghost": None}


def _destroy_drag_ghost():
    if palette_drag["ghost"] is not None:
        palette_drag["ghost"].destroy()
        palette_drag["ghost"] = None


def _reset_palette_drag():
    _destroy_drag_ghost()
    palette_drag.update(kit=None, type=None, origin=None, active=False)


def on_palette_press(event):
    item = palette_tree.identify_row(event.y)
    if not item:
        _reset_palette_drag()
        return

    palette_tree.selection_set(item)
    index = palette_kit_combo.current()
    if index < 0 or index >= len(palette_kit_names):
        return

    palette_drag.update(
        kit=palette_kit_names[index],
        type=palette_tree.item(item, "text"),
        origin=(event.x_root, event.y_root),
        active=False,
    )


def on_palette_motion(event):
    if palette_drag["type"] is None or palette_drag["origin"] is None:
        return

    origin_x, origin_y = palette_drag["origin"]
    moved = abs(event.x_root - origin_x) + abs(event.y_root - origin_y)

    if not palette_drag["active"]:
        if moved < DRAG_THRESHOLD:
            return
        palette_drag["active"] = True

        ghost = tk.Toplevel(window)
        ghost.overrideredirect(True)
        ghost.attributes("-topmost", True)
        tk.Label(
            ghost, text=f"{palette_drag['type']}",
            bg="#dce6f2", fg="black", relief="solid", borderwidth=1,
            padx=6, pady=2, font=("TkDefaultFont", 9),
        ).pack()
        palette_drag["ghost"] = ghost

    if palette_drag["ghost"] is not None:
        palette_drag["ghost"].geometry(f"+{event.x_root + 12}+{event.y_root + 10}")


def _pointer_over_canvas(x_root, y_root):
    left = canvas.winfo_rootx()
    top = canvas.winfo_rooty()
    return (left <= x_root < left + canvas.winfo_width()
            and top <= y_root < top + canvas.winfo_height())


def on_palette_release(event):
    was_dragging = palette_drag["active"]
    kit_name = palette_drag["kit"]
    type_name = palette_drag["type"]
    _reset_palette_drag()

    if not was_dragging or not kit_name or not type_name:
        return

    if not _pointer_over_canvas(event.x_root, event.y_root):
        return

    if app_state.xml_root_element is None:
        messagebox.showwarning("Add Component", "Open a SAX file first.")
        return

    # Pointer position -> canvas coordinates -> grid units, snapped like a dragged box.
    drop_x = canvas.canvasx(event.x_root - canvas.winfo_rootx())
    drop_y = canvas.canvasy(event.y_root - canvas.winfo_rooty())

    step = app_state.meta_scale
    min_step = wiresheet.layout_margin(step) // step
    grid_x = max(min_step, min(wiresheet.META_COORD_MAX, round(drop_x / step)))
    grid_y = max(min_step, min(wiresheet.META_COORD_MAX, round(drop_y / step)))

    sax_file.add_component(kit_name, type_name, grid_x, grid_y)


palette_kit_names = []
palette_kit_combo.bind("<<ComboboxSelected>>", populate_palette_types)
palette_tree.bind("<ButtonPress-1>", on_palette_press)
palette_tree.bind("<B1-Motion>", on_palette_motion)
palette_tree.bind("<ButtonRelease-1>", on_palette_release)

left_pane.add(frame_palette, weight=2)

# weight=0 keeps the tree/palette column out of the share-out of spare width, so growing
# the window feeds the wiresheet alone and the column stays at its configured width.
paned_window.add(left_pane, weight=0)

frame_editor = ttk.Frame(paned_window)

canvas_vscroll = ttk.Scrollbar(frame_editor, orient=tk.VERTICAL)
canvas_vscroll.pack(side=tk.RIGHT, fill=tk.Y)

canvas_hscroll = ttk.Scrollbar(frame_editor, orient=tk.HORIZONTAL)
canvas_hscroll.pack(side=tk.BOTTOM, fill=tk.X)

canvas = tk.Canvas(
    frame_editor,
    bg="white",
    highlightthickness=0,
    xscrollcommand=canvas_hscroll.set,
    yscrollcommand=canvas_vscroll.set,
    scrollregion=(0, 0, 2000, 2000),
)
app_state.canvas = canvas
canvas.pack(fill=tk.BOTH, expand=True)

canvas_vscroll.config(command=canvas.yview)
canvas_hscroll.config(command=canvas.xview)

canvas.bind("<ButtonPress-1>", on_canvas_click)
canvas.bind("<B1-Motion>", on_canvas_drag)
canvas.bind("<ButtonRelease-1>", on_canvas_release)
canvas.bind("<Configure>", lambda e: wiresheet.draw_grid())

canvas.bind("<ButtonPress-3>", on_canvas_right_click)
canvas.bind("<ButtonPress-2>", on_canvas_right_click)

paned_window.add(frame_editor, weight=3)

undo.set_refresh_callback(refresh_all_views)
sax_file.set_tree_filled_callback(lambda: fit_tree_column(tree))
refresh_palette_kits()
apply_left_pane_width()

# Moving the sash changes the split directly; resizing the window changes what fits.
left_pane.bind("<B1-Motion>", clamp_left_pane_split, add="+")
left_pane.bind("<ButtonRelease-1>", clamp_left_pane_split, add="+")
left_pane.bind("<Configure>", clamp_left_pane_split, add="+")

window.after(100, verify_startup_configurations)
window.mainloop()