"""
core/reference_registry.py

Generic (device_id, channel_id) reference-rename propagation.

A Signal (physical device channel) or a Channel (derived, device_id ==
"derived") can be renamed by the user. Both kinds are referenced the same
way everywhere downstream — plot traces, control targets, filter
pipelines, other derived channels' sources — as a plain
(device_id, channel_id) pair. Renaming one without rewriting every
reference to it leaves those references dangling: they silently stop
receiving data (this is exactly the bug that motivated this module — an
Arduino analog pin remap changed a Signal's id and orphaned its plot
trace).

propagate_rename() is the single place that walks every subsystem able to
hold such a reference and rewrites it. It expects a MainWindow instance
(or anything exposing the same .engine/.processor/._chart/._ctrl/
._win_config attributes) since that's the one place all of them are
reachable from.
"""

from typing import Tuple

Ref = Tuple[str, str]


def propagate_rename(app, old_ref: Ref, new_ref: Ref) -> None:
    if old_ref == new_ref:
        return

    # Physical signals live in the acquisition engine's buffers; derived
    # Channels don't (their buffers live in SignalProcessor._derived_bufs).
    if old_ref[0] != "derived":
        app.engine.rename_channel(old_ref[0], old_ref[1], new_ref[1])

    # Filter pipelines, other derived channels' sources, latest-value cache,
    # and (if old_ref is itself a derived Channel) its ring buffer.
    app.processor.rename_reference(old_ref, new_ref)

    # Live plot — trace specs in the strip chart's current layout.
    chart = getattr(app, "_chart", None)
    changed = False
    if chart is not None and chart._cfg is not None:
        for pane in chart._cfg.panes:
            for tr in pane.traces:
                if (tr.device_id, tr.channel_id) == old_ref:
                    tr.device_id, tr.channel_id = new_ref
                    changed = True
    if changed:
        chart.refresh()

    # Control panel — saved specs (profile persistence) + live bound widgets
    # (actual I/O routing — ControlWidget reads its own .device_id/.channel_id
    # directly in _write()/_check_stale(), not from the spec).
    ctrl = getattr(app, "_ctrl", None)
    if ctrl is not None:
        for spec in ctrl.get_specs():
            if (spec.device_id, spec.channel_id) == old_ref:
                spec.device_id, spec.channel_id = new_ref
        for widget in getattr(ctrl, "_widgets", []):
            if (widget.device_id, widget.channel_id) == old_ref:
                widget.device_id, widget.channel_id = new_ref

    # Config window tabs, if currently open — refresh so pickers/tables
    # don't show the stale id until next full refresh.
    win = getattr(app, "_win_config", None)
    if win is not None:
        if chart is not None:
            win.refresh_plot(chart._cfg)
        if hasattr(win, "refresh_derived"):
            win.refresh_derived()
        if hasattr(win, "refresh_devices"):
            win.refresh_devices()