"""Gestion des tunnels SSH (redirections de ports) d'une session ouverte."""
from __future__ import annotations

from PySide6.QtCore import Qt
from PySide6.QtWidgets import (
    QDialog, QVBoxLayout, QHBoxLayout, QFormLayout, QTreeWidget, QTreeWidgetItem,
    QPushButton, QComboBox, QSpinBox, QLineEdit, QLabel, QMessageBox, QAbstractItemView,
)

from app.tunnels import DIRECTION_DYNAMIC, DIRECTION_LABELS, TunnelManager, describe


class TunnelDialog(QDialog):
    def __init__(self, manager: TunnelManager, parent=None):
        super().__init__(parent)
        self.manager = manager
        self.setWindowTitle("Tunnels SSH (redirection de ports)")
        self.setMinimumSize(660, 400)

        layout = QVBoxLayout(self)

        info = QLabel(
            "Une redirection <b>locale</b> ouvre un port sur votre poste et l'envoie, a travers "
            "la connexion SSH, vers une machine joignable depuis le serveur — pratique pour "
            "atteindre un service qui n'ecoute que sur la boucle locale du serveur.<br>"
            "Une redirection <b>distante</b> fait l'inverse : un port ouvert sur le serveur est "
            "relaye vers une machine joignable depuis votre poste.<br>"
            "Une redirection <b>dynamique</b> ouvre un proxy SOCKS sur votre poste : chaque "
            "application qui s'y connecte choisit elle-meme sa destination, atteinte a travers "
            "la connexion SSH (pratique pour naviguer comme si vous etiez sur le reseau du serveur)."
        )
        info.setWordWrap(True)
        layout.addWidget(info)

        self.tree = QTreeWidget()
        self.tree.setHeaderLabels(["Sens", "Redirection", "Etat"])
        self.tree.setRootIsDecorated(False)
        self.tree.setSelectionMode(QAbstractItemView.SingleSelection)
        self.tree.setColumnWidth(0, 110)
        self.tree.setColumnWidth(1, 380)
        layout.addWidget(self.tree)

        form = QFormLayout()
        self.direction = QComboBox()
        for key, label in DIRECTION_LABELS.items():
            self.direction.addItem(label, key)
        self.listen_port = QSpinBox(); self.listen_port.setRange(1, 65535); self.listen_port.setValue(8080)
        self.dest_host = QLineEdit("127.0.0.1")
        self.dest_port = QSpinBox(); self.dest_port.setRange(1, 65535); self.dest_port.setValue(80)

        form.addRow("Sens :", self.direction)
        form.addRow("Port a ouvrir :", self.listen_port)
        form.addRow("Machine de destination :", self.dest_host)
        form.addRow("Port de destination :", self.dest_port)
        layout.addLayout(form)
        self.form = form

        self.direction.currentIndexChanged.connect(self._update_dest_fields)
        self._update_dest_fields()

        buttons = QHBoxLayout()
        self.add_btn = QPushButton("Ouvrir le tunnel")
        self.add_btn.setObjectName("primary")
        self.remove_btn = QPushButton("Fermer le tunnel selectionne")
        buttons.addWidget(self.add_btn)
        buttons.addWidget(self.remove_btn)
        buttons.addStretch()
        close_btn = QPushButton("Fermer")
        close_btn.clicked.connect(self.accept)
        buttons.addWidget(close_btn)
        layout.addLayout(buttons)

        self.add_btn.clicked.connect(self.add_tunnel)
        self.remove_btn.clicked.connect(self.remove_tunnel)
        self.refresh()

    def _update_dest_fields(self) -> None:
        """La destination d'une redirection dynamique (-D) est negociee par
        chaque client SOCKS : les champs n'ont pas de sens dans ce mode."""
        has_dest = self.direction.currentData() != DIRECTION_DYNAMIC
        self.form.setRowVisible(self.dest_host, has_dest)
        self.form.setRowVisible(self.dest_port, has_dest)

    def refresh(self) -> None:
        self.tree.clear()
        for tunnel in self.manager.tunnels:
            etat = f"Erreur : {tunnel.error}" if tunnel.error else "Actif"
            item = QTreeWidgetItem([
                DIRECTION_LABELS.get(tunnel.direction, tunnel.direction),
                describe(tunnel.config),
                etat,
            ])
            item.setData(0, Qt.UserRole, id(tunnel))
            self.tree.addTopLevelItem(item)
        self.remove_btn.setEnabled(bool(self.manager.tunnels))

    def add_tunnel(self) -> None:
        direction = self.direction.currentData()
        if direction != DIRECTION_DYNAMIC and not self.dest_host.text().strip():
            QMessageBox.warning(self, "Destination manquante", "Indiquez la machine de destination.")
            return
        config = {"direction": direction, "listen_port": self.listen_port.value()}
        if direction != DIRECTION_DYNAMIC:
            config["dest_host"] = self.dest_host.text().strip()
            config["dest_port"] = self.dest_port.value()
        tunnel = self.manager.start(config)
        if tunnel.error:
            QMessageBox.critical(
                self, "Tunnel impossible",
                f"{describe(config)}\n\n{tunnel.error}\n\n"
                "Le port est peut-etre deja utilise sur le poste.",
            )
            self.manager.stop(tunnel)
        self.refresh()

    def remove_tunnel(self) -> None:
        item = self.tree.currentItem()
        if not item:
            return
        target = item.data(0, Qt.UserRole)
        for tunnel in list(self.manager.tunnels):
            if id(tunnel) == target:
                self.manager.stop(tunnel)
                break
        self.refresh()