"""Shared configuration, runtime state and widget handles.

Every other module reaches this state as ``app_state.<name>`` rather than importing
the names directly. A plain ``from app_state import is_dirty`` would copy the value,
so later rebinding would only ever be seen by the module that did it.
"""

import configparser
import os

VERSION = "0.0.0.102"
PROPERTIES_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)), "editor.properties")
DEFAULT_GRID_SIZE = 10
DEFAULT_ADD_TIMESTAMP = True

# Purely a display choice, so it lives in editor.properties. The SAX file has nowhere to
# record it: meta stores a position and nothing about box size.
DEFAULT_BOX_WIDTH = 100
MIN_ALLOWED_BOX_WIDTH = 60
MAX_ALLOWED_BOX_WIDTH = 400

# The tree and palette column is held at this width whatever the window does, so a wider
# window only ever gives the wiresheet more room. The sash can still be dragged; this is
# the width the column is set to at startup and whenever the preference changes.
DEFAULT_LEFT_PANE_WIDTH = 230
MIN_ALLOWED_LEFT_PANE_WIDTH = 120
MAX_ALLOWED_LEFT_PANE_WIDTH = 600

# Called whenever "is there anything unwritten" may have changed, so the file name on
# the tree can follow it. main registers it; anything before that is a no-op.
dirty_display_callback = None

# Widget handles, filled in by main once the UI exists
window = None
canvas = None
tree = None
status_label = None      # the window's bottom status bar

# The unsaved-state tint. The wiresheet paints it on the canvas and the Properties view
# paints it on itself, so "there is something here you have not written yet" is one
# colour wherever the change was made.
DIRTY_TINT = "#ffe6e6"
CLEAN_TINT = "white"

# The file name on the tree's root row turns this colour while anything is unwritten,
# which is the one place a file name appears on screen -- a Tk window title cannot be
# coloured.
#
# The tag's colour is configured once and never changed; what moves is whether the row
# carries the tag. Reconfiguring a tag does not reliably repaint rows that are already
# drawn -- which is why the name only ever went red on the paths that happened to rebuild
# the tree, and stayed black after a box was dragged. Setting a row's tags repaints that
# row, so the two states cannot drift apart.
DIRTY_NAME_COLOUR = "#c00000"
DIRTY_NAME_TAG = "unsaved_file"

# A themed Treeview maps the selected state to SystemHighlightText, and that mapping beats
# a row tag's own foreground -- so the file name turned white-on-blue the moment its row
# was selected, which is exactly when the root sheet is the one being looked at. The
# navigation tree therefore runs on a style of its own that drops the selected foreground
# and picks a light selection background instead, so a tag's colour shows in every state
# and black text still reads on the highlight.
NAV_TREE_STYLE = "Nav.Treeview"
NAV_SELECTION_BG = "#cce4f7"

# Status bar tones. A hint that something needs attention later is worth a colour, so a
# placement that leaves the schema out of step is not read as a plain confirmation.
STATUS_INFO_COLOUR = "#333333"
STATUS_WARN_COLOUR = "#a04b00"

# Maps to hold tracking states
tree_element_map = {}       # Treeview item ID -> ET.Element
canvas_comp_map = {}        # Canvas item tag -> ET.Element
canvas_tag_by_element = {}  # ET.Element -> Canvas unique tag string
component_slot_offsets = {} # Canvas unique tag -> {slot name: y offset from box top}

# File modification tracking state
is_dirty = False
current_file_path = None
active_components_list = []   # Tracks what components are actively painted
selected_canvas_tag = None    # Tracks the currently clicked/highlighted canvas component tag
selected_tree_item_id = None  # Tracks the currently right-clicked Treeview item
link_mark_element = None      # Component marked as a link endpoint via "Link Mark"
selected_link_tag = None      # Canvas tag of the currently selected (red-highlighted) link wire
unroutable_link_count = 0     # Links drawn as knobs because no wire could avoid a component
meta_scale = DEFAULT_GRID_SIZE  # Pixels per meta coordinate step on the painted sheet
zoom = 1.0                    # Scale the open sheet is painted at; 1.0 is one pixel per pixel
knob_link_ends = {}           # wire tag -> (x1, y1, x2, y2) for a link shown as two knobs
canvas_link_map = {}          # Canvas link tag -> ET.Element (<link>)
xml_root_element = None       # Keep a persistent root reference to redraw tree layouts cleanly
current_sheet_parent = None   # Element whose children are painted; None means the app root

# Drag-and-drop state variables
drag_data = {"x": 0, "y": 0, "tag": None}

# Global component slot registries compiled dynamically per file load
final_components_registry = {}
active_schema_kits = {}      # kit name -> checksum, as the open file's <schema> declares them

# Kits a placed component needs that the file's <schema> does not declare yet, as
# kit name -> checksum resolved from Sedona home. Filled in when a palette component is
# placed and read back when saving, which is where the <schema> block is reconciled.
pending_schema_kits = {}


def load_preferences():
    """Loads application configurations from editor.properties or initializes defaults."""
    config = configparser.ConfigParser()
    grid_size = DEFAULT_GRID_SIZE
    add_timestamp = DEFAULT_ADD_TIMESTAMP
    box_width = DEFAULT_BOX_WIDTH
    left_pane_width = DEFAULT_LEFT_PANE_WIDTH
    sedona_home = ""
    trace_dasp = False

    if os.path.exists(PROPERTIES_FILE):
        try:
            config.read(PROPERTIES_FILE)
            grid_size = config.getint("Editor", "grid_size", fallback=DEFAULT_GRID_SIZE)
            add_timestamp = config.getboolean("Editor", "add_timestamp", fallback=DEFAULT_ADD_TIMESTAMP)
            box_width = config.getint("Editor", "box_width", fallback=DEFAULT_BOX_WIDTH)
            left_pane_width = config.getint(
                "Editor", "left_pane_width", fallback=DEFAULT_LEFT_PANE_WIDTH
            )
            sedona_home = config.get("Editor", "sedona.home", fallback="").strip()
            trace_dasp = config.getboolean("Editor", "trace_dasp", fallback=False)
        except Exception:
            pass
    else:
        config["Editor"] = {
            "sedona.home": "",
            "grid_size": str(DEFAULT_GRID_SIZE),
            "add_timestamp": str(DEFAULT_ADD_TIMESTAMP),
            "box_width": str(DEFAULT_BOX_WIDTH),
            "left_pane_width": str(DEFAULT_LEFT_PANE_WIDTH)
        }
        try:
            with open(PROPERTIES_FILE, "w") as configfile:
                config.write(configfile)
        except Exception:
            pass

    box_width = max(MIN_ALLOWED_BOX_WIDTH, min(MAX_ALLOWED_BOX_WIDTH, box_width))
    left_pane_width = max(
        MIN_ALLOWED_LEFT_PANE_WIDTH, min(MAX_ALLOWED_LEFT_PANE_WIDTH, left_pane_width)
    )
    return sedona_home, grid_size, add_timestamp, box_width, left_pane_width, trace_dasp


def save_preferences():
    """Writes the current preference values back to editor.properties."""
    config = configparser.ConfigParser()
    config["Editor"] = {
        "sedona.home": SEDONA_HOME,
        "grid_size": str(GRID_SIZE),
        "add_timestamp": str(ADD_TIMESTAMP),
        "box_width": str(BOX_WIDTH),
        "left_pane_width": str(LEFT_PANE_WIDTH),
        "trace_dasp": str(TRACE_DASP),
    }
    with open(PROPERTIES_FILE, "w") as configfile:
        config.write(configfile)


def base_window_title():
    """The window title with no file context, which handlers extend with their own suffix."""
    return f"Sedona SAX Offline Program Editor [v{VERSION}]"


def set_status(message, warn=False):
    """Posts a one-line note to the status bar. A no-op before the UI exists."""
    if status_label is None:
        return
    status_label.config(
        text=message,
        foreground=STATUS_WARN_COLOUR if warn else STATUS_INFO_COLOUR
    )


def clear_status():
    """Empties the status bar, for when the note no longer describes anything on screen."""
    set_status("")


def refresh_dirty_display():
    """Nudges whatever shows 'there is something unwritten'. A no-op before the UI exists."""
    if dirty_display_callback is not None:
        dirty_display_callback()


def mark_dirty():
    """Single funnel for 'the document changed', including the unsaved-state tint."""
    global is_dirty
    if not is_dirty:
        is_dirty = True
        if canvas is not None:
            canvas.config(bg=DIRTY_TINT)
    refresh_dirty_display()


def mark_clean():
    """Clears the unsaved-state marker after a successful save or a fresh load."""
    global is_dirty
    is_dirty = False
    if canvas is not None:
        canvas.config(bg=CLEAN_TINT)
    refresh_dirty_display()


# ── Live device connection state ────────────────────────────────
live_mode = False
device_session = None       # device_session.DeviceSession instance
device_host = ""
device_port = 1876
connection_status = "offline"  # offline | connecting | connected | error


def base_window_title_live():
    """Window title for live mode."""
    return f"Sedona Live Editor [v{VERSION}] — {device_host}:{device_port}"


SEDONA_HOME, GRID_SIZE, ADD_TIMESTAMP, BOX_WIDTH, LEFT_PANE_WIDTH, TRACE_DASP = load_preferences()