"""Bố cục khung chat — R08-T06.

Hai cột: mạch hội thoại bên trái, khung tệp đầu ra bên phải. Ô nhập nằm dưới
CẢ HAI cột — đó là lý do khung tệp đứng cạnh mạch hội thoại mà không làm hẹp
chỗ gõ. Đặt trong cột chat thì ô nhập co lại mỗi lần có tệp xuất hiện.

Vài widget cố ý được gắn vào một cha ẩn vĩnh viễn thay vì bỏ hẳn: khung tệp
đầu vào và bảng kế hoạch cũ vẫn còn được gọi ``set_steps``/``add`` ở nơi
khác. Không có cha thì lần gọi đầu tiên sẽ bật lên thành một cửa sổ nổi lạc
lõng giữa màn hình.

Cùng kiểu mixin, xem ghi chú ở đầu ``presentation/shell/nav_rail.py``.
"""
from __future__ import annotations

from pathlib import Path
from typing import Any, Dict, List, Optional
from PySide6.QtCore import Qt, QTimer, Signal
from PySide6.QtCore import QFileSystemWatcher
from PySide6.QtWidgets import (
    QComboBox, QHBoxLayout, QLabel, QMessageBox, QPushButton, QSplitter,
    QVBoxLayout, QWidget,
)
from ...core.worker import AgentWorker
from ...i18n import on_language_changed, tr
from ...state import AppContext
from ...theme import current_palette
from .chat_bubble_style import ThinkingIndicator
from .chat_history_widget import ChatView
from .composer_widget import Composer
from ...ui.icons import collapse_right_icon, icon as app_icon
from ...ui.osutil import is_image, open_path
from ...ui.widgets import CollapsibleSection, CollapseStrip, PlanSection


class ChatPanelLayoutMixin:
    """Dựng bố cục. Trộn vào ChatPanel."""

    def _build_layout(self, root) -> None:
        """``root`` là QVBoxLayout gốc do ``__init__`` dựng."""
        # Chat column: transcript expands, the chat box is pinned at the bottom.
        chat_col = QWidget()
        cc = QVBoxLayout(chat_col)
        cc.setContentsMargins(0, 0, 0, 0)
        cc.setSpacing(0)
        cc.addWidget(self.chat_view, 1)
        self.thinking = ThinkingIndicator()   # animated "working…" line while we wait
        cc.addWidget(self.thinking)
        self.center_split = QSplitter(Qt.Horizontal)
        self.center_split.addWidget(chat_col)
        root.addWidget(self.center_split, 1)

        # The composer spans the whole screen, under BOTH columns — that is how
        # the drawing lays it out, and it is the reason the files panel can sit
        # beside the transcript without narrowing what you type into. Inside the
        # chat column it stopped at the panel's edge and the input shrank
        # whenever files appeared.
        composer_wrap = QWidget()
        cwl = QVBoxLayout(composer_wrap)
        cwl.setContentsMargins(8, 4, 8, 8)
        cwl.addWidget(self.composer)
        root.addWidget(composer_wrap)

        # Right sidebar: Output files only (see below — Input is tracked but
        # not shown).
        self.input_section = CollapsibleSection(tr("widgets.input_files"))
        # No cap: this section owns the whole right panel (its header is
        # hoisted into io_hdr below), so the list should fill the space down
        # to the composer instead of stopping at a fixed height with empty
        # panel below it.
        self.output_section = CollapsibleSection(tr("widgets.output_files").upper(), max_height=None)
        # Input files are NOT shown in Cowork's UI anymore — but they're still
        # fully tracked (add/remove/paths()) exactly as before, since that list
        # is what gets written into the conversation's own "inputs" field on
        # save (kept alongside the conversation; nothing here deletes the
        # user's actual files — the conversation JSON itself only disappears
        # when the conversation is deleted, same as always). Give input_section
        # a real, permanently-hidden PARENT (not just "never added to a layout")
        # so its own internal auto-show-on-add() call can never pop it up as a
        # stray floating window.
        self._input_hidden_host = QWidget(self)
        self._input_hidden_host.setVisible(False)
        _hh_lay = QVBoxLayout(self._input_hidden_host)
        _hh_lay.setContentsMargins(0, 0, 0, 0)
        _hh_lay.addWidget(self.input_section)
        self.plan_section = PlanSection(tr("widgets.plan_title"))   # live step checklist, above the Files panel
        # The plan is shown INLINE in the conversation now (see add_plan), so this
        # legacy right-panel checklist is parked inside the permanently-hidden
        # host. Without a parent it would pop as a stray top-level "Plan (N)"
        # window the moment set_steps() made it visible — parenting it here keeps
        # its set_steps/clear calls truly inert (a hidden ancestor never renders).
        _hh_lay.addWidget(self.plan_section)
        self.input_section.activated.connect(self._open_io_item)
        self.output_section.activated.connect(self._open_io_item)
        # Right-click a file → Open / "View & AI Edit" (in-app viewer+editor).
        for section in (self.input_section, self.output_section):
            section.list.setContextMenuPolicy(Qt.CustomContextMenu)
            section.list.customContextMenuRequested.connect(
                lambda pos, s=section: self._io_context_menu(s, pos))
        self._io_widget = QWidget()
        iol = QVBoxLayout(self._io_widget)
        iol.setContentsMargins(6, 6, 6, 6)
        iol.setSpacing(4)
        io_hdr = QHBoxLayout()
        self._io_collapse_btn = QPushButton()
        self._io_collapse_btn.setIcon(collapse_right_icon())
        self._io_collapse_btn.setFixedWidth(28)
        self._io_collapse_btn.clicked.connect(lambda: self._set_io_collapsed(True))
        self._files_header = QLabel()
        self._files_header.setStyleSheet("font-weight:600;")
        # The drawing gives this panel ONE heading — "TỆP ĐẦU RA (3) ›" — and
        # the section already draws exactly that, count included. A separate
        # "Files" label above it was the same thing said twice, so the section's
        # own header moves onto this row and the collapse chevron sits at its
        # right, where the drawing puts it. _files_header stays for the tabs
        # that still label their panel, just not in this layout.
        self._files_header.setVisible(False)
        io_hdr.addWidget(self.output_section.header, 1)
        io_hdr.addWidget(self._io_collapse_btn)
        # The plan now shows INLINE in the conversation (an expandable block whose
        # steps tick off as they complete), not in this right panel — so it's kept
        # out of the layout here. The object stays (its set_steps/clear calls are
        # harmless no-ops on a hidden widget).
        self.plan_section.setVisible(False)
        iol.addLayout(io_hdr)
        bl_host = QWidget()
        bl = QVBoxLayout(bl_host)
        bl.setContentsMargins(0, 0, 0, 0)
        bl.setSpacing(4)
        bl.addWidget(self.output_section, 1)   # Output only — Input is tracked but hidden; fills down to the composer
        iol.addWidget(bl_host, 1)

        # Collapsing shrinks the panel to a thin clickable line (not hidden).
        # The collapse button lives in the panel header; the strip re-expands.
        self._io_strip = CollapseStrip(tr("chatpanel.expand_files_tooltip"), expand_dir="left")
        self._io_strip.clicked.connect(lambda: self._set_io_collapsed(False))
        self._io_strip.setVisible(False)
        self._io_pane = QWidget()
        pl = QHBoxLayout(self._io_pane)
        pl.setContentsMargins(0, 0, 0, 0)
        pl.setSpacing(0)
        pl.addWidget(self._io_strip)
        pl.addWidget(self._io_widget, 1)

        self.center_split.addWidget(self._io_pane)
        self.center_split.setStretchFactor(0, 1)
        self.center_split.setStretchFactor(1, 0)
        self.center_split.setChildrenCollapsible(False)
        self.center_split.setSizes([820, 220])
        on_language_changed(self._retranslate_base)