"""
New / Edit connection dialog.
Supports MySQL, PostgreSQL, SQLite, and SQL Server.
"""
from PyQt6.QtWidgets import (
    QDialog, QDialogButtonBox, QFormLayout, QHBoxLayout, QVBoxLayout,
    QLabel, QLineEdit, QComboBox, QSpinBox, QCheckBox, QPushButton,
    QTabWidget, QWidget, QFileDialog, QMessageBox, QFrame, QColorDialog,
)
from PyQt6.QtCore import Qt
from PyQt6.QtGui import QColor

from app.models.connection_model import ConnectionProfile
from app.config.connections import save_profile


class ColorButton(QPushButton):
    """A button that shows a solid colour and opens a colour picker."""

    def __init__(self, color: str = "#8caaee", parent=None):
        super().__init__(parent)
        self._color = color
        self.setFixedSize(32, 24)
        self._refresh()
        self.clicked.connect(self._pick)

    def _refresh(self):
        self.setStyleSheet(
            f"background-color:{self._color}; border:1px solid #51576d; border-radius:4px;"
        )

    def _pick(self):
        col = QColorDialog.getColor(QColor(self._color), self, "Pick a colour")
        if col.isValid():
            self._color = col.name()
            self._refresh()

    @property
    def color(self) -> str:
        return self._color

    @color.setter
    def color(self, value: str):
        self._color = value
        self._refresh()


class ConnectionDialog(QDialog):
    """Dialog for creating or editing a ConnectionProfile."""

    DB_TYPES = [
        ("MySQL",       "mysql",      3306),
        ("PostgreSQL",  "postgresql", 5432),
        ("SQLite",      "sqlite",     0),
        ("SQL Server",  "mssql",      1433),
    ]

    def __init__(self, profile: ConnectionProfile = None, parent=None):
        super().__init__(parent)
        self._profile  = profile
        self._editing  = profile is not None
        self.setWindowTitle("Edit Connection" if self._editing else "New Connection")
        self.setMinimumWidth(520)
        self.setModal(True)
        self._build_ui()
        if self._editing:
            self._populate(profile)

    # ── UI construction ───────────────────────────────────────────────────────

    def _build_ui(self):
        root = QVBoxLayout(self)
        root.setSpacing(0)

        # ── Tabs ──────────────────────────────────────────────────────────────
        tabs = QTabWidget()
        tabs.addTab(self._build_general_tab(), "General")
        tabs.addTab(self._build_ssl_tab(),     "SSL / Advanced")
        root.addWidget(tabs)

        # ── Buttons ───────────────────────────────────────────────────────────
        self._test_btn = QPushButton("Test Connection")
        self._test_btn.clicked.connect(self._test_connection)

        bbox = QDialogButtonBox(
            QDialogButtonBox.StandardButton.Ok |
            QDialogButtonBox.StandardButton.Cancel
        )
        bbox.accepted.connect(self._accept)
        bbox.rejected.connect(self.reject)
        ok_btn = bbox.button(QDialogButtonBox.StandardButton.Ok)
        if ok_btn:
            ok_btn.setDefault(True)

        btn_row = QHBoxLayout()
        btn_row.addWidget(self._test_btn)
        btn_row.addStretch()
        btn_row.addWidget(bbox)
        root.addSpacing(8)
        root.addLayout(btn_row)

    def _build_general_tab(self) -> QWidget:
        w = QWidget()
        form = QFormLayout(w)
        form.setRowWrapPolicy(QFormLayout.RowWrapPolicy.DontWrapRows)
        form.setLabelAlignment(Qt.AlignmentFlag.AlignRight)
        form.setSpacing(10)
        form.setContentsMargins(16, 16, 16, 8)

        # Connection name + colour
        name_row = QHBoxLayout()
        self._name = QLineEdit()
        self._name.setPlaceholderText("My Database")
        self._color_btn = ColorButton()
        name_row.addWidget(self._name, 1)
        name_row.addWidget(self._color_btn)
        form.addRow("Name:", name_row)

        # DB type selector
        self._db_type = QComboBox()
        for label, _, _ in self.DB_TYPES:
            self._db_type.addItem(label)
        self._db_type.currentIndexChanged.connect(self._on_type_changed)
        form.addRow("Type:", self._db_type)

        # Separator line
        line = QFrame()
        line.setFrameShape(QFrame.Shape.HLine)
        form.addRow(line)

        # Host / port
        hp = QHBoxLayout()
        self._host = QLineEdit()
        self._host.setPlaceholderText("localhost")
        self._port = QSpinBox()
        self._port.setRange(1, 65535)
        self._port.setValue(3306)
        self._port.setFixedWidth(90)
        hp.addWidget(self._host, 1)
        hp.addWidget(QLabel("Port:"))
        hp.addWidget(self._port)
        form.addRow("Host:", hp)

        # Database / file path
        db_row = QHBoxLayout()
        self._database = QLineEdit()
        self._database.setPlaceholderText("database name or file path")
        self._browse_btn = QPushButton("Browse…")
        self._browse_btn.setFixedWidth(80)
        self._browse_btn.clicked.connect(self._browse_file)
        self._browse_btn.setVisible(False)
        db_row.addWidget(self._database, 1)
        db_row.addWidget(self._browse_btn)
        form.addRow("Database:", db_row)

        # Username / password
        self._username = QLineEdit()
        self._username.setPlaceholderText("username")
        form.addRow("Username:", self._username)

        self._password = QLineEdit()
        self._password.setPlaceholderText("password")
        self._password.setEchoMode(QLineEdit.EchoMode.Password)
        form.addRow("Password:", self._password)

        # Timeout
        self._timeout = QSpinBox()
        self._timeout.setRange(1, 300)
        self._timeout.setValue(30)
        self._timeout.setSuffix(" sec")
        form.addRow("Timeout:", self._timeout)

        # Enter in password submits the dialog
        self._password.returnPressed.connect(self._accept)

        # Focus starts on the name field
        self._name.setFocus()

        return w

    def _build_ssl_tab(self) -> QWidget:
        w = QWidget()
        form = QFormLayout(w)
        form.setSpacing(10)
        form.setContentsMargins(16, 16, 16, 8)

        self._ssl = QCheckBox("Use SSL / TLS")
        form.addRow(self._ssl)

        self._ssl_ca   = self._file_row(form, "CA Certificate:")
        self._ssl_cert = self._file_row(form, "Client Certificate:")
        self._ssl_key  = self._file_row(form, "Client Key:")
        return w

    def _file_row(self, form: QFormLayout, label: str) -> QLineEdit:
        row = QHBoxLayout()
        le = QLineEdit()
        le.setPlaceholderText("(optional) path to file")
        btn = QPushButton("…")
        btn.setFixedWidth(32)
        btn.clicked.connect(lambda: self._choose_file(le))
        row.addWidget(le, 1)
        row.addWidget(btn)
        form.addRow(label, row)
        return le

    # ── Slots ─────────────────────────────────────────────────────────────────

    def _on_type_changed(self, idx: int):
        _, db_type, default_port = self.DB_TYPES[idx]
        is_sqlite = (db_type == "sqlite")
        self._host.setEnabled(not is_sqlite)
        self._port.setEnabled(not is_sqlite)
        self._username.setEnabled(not is_sqlite)
        self._password.setEnabled(not is_sqlite)
        self._browse_btn.setVisible(is_sqlite)
        if default_port:
            self._port.setValue(default_port)

    def _browse_file(self):
        path, _ = QFileDialog.getOpenFileName(
            self, "Select SQLite File", "",
            "SQLite Databases (*.db *.sqlite *.sqlite3);;All Files (*)"
        )
        if path:
            self._database.setText(path)

    def _choose_file(self, target: QLineEdit):
        path, _ = QFileDialog.getOpenFileName(self, "Select File", "", "All Files (*)")
        if path:
            target.setText(path)

    def _test_connection(self):
        p = self._build_profile()
        from app.drivers import get_driver
        try:
            driver = get_driver(p.db_type, self._driver_config(p))
            ok, msg = driver.test_connection()
        except Exception as e:
            ok, msg = False, str(e)

        icon = "✅" if ok else "❌"
        QMessageBox.information(self, "Test Connection", f"{icon}  {msg}")

    def _accept(self):
        if not self._name.text().strip():
            QMessageBox.warning(self, "Validation", "Connection name is required.")
            return
        profile = self._build_profile()
        save_profile(profile)
        self._profile = profile
        self.accept()

    # ── Helpers ───────────────────────────────────────────────────────────────

    def _build_profile(self) -> ConnectionProfile:
        idx = self._db_type.currentIndex()
        _, db_type, _ = self.DB_TYPES[idx]
        base = self._profile if self._editing else ConnectionProfile(
            name="", db_type=db_type
        )
        base.name     = self._name.text().strip()
        base.db_type  = db_type
        base.host     = self._host.text().strip()
        base.port     = self._port.value()
        base.database = self._database.text().strip()
        base.username = self._username.text().strip()
        base.password = self._password.text()
        base.color    = self._color_btn.color
        base.ssl      = self._ssl.isChecked()
        base.ssl_ca   = self._ssl_ca.text().strip()
        base.ssl_cert = self._ssl_cert.text().strip()
        base.ssl_key  = self._ssl_key.text().strip()
        base.connection_timeout = self._timeout.value()
        return base

    @staticmethod
    def _driver_config(p: ConnectionProfile) -> dict:
        return dict(
            host=p.host, port=p.port, database=p.database,
            user=p.username, password=p.password,
            connection_timeout=p.connection_timeout,
        )

    def _populate(self, p: ConnectionProfile):
        self._name.setText(p.name)
        self._color_btn.color = p.color
        # Set db type combo
        for i, (_, db_type, _) in enumerate(self.DB_TYPES):
            if db_type == p.db_type:
                self._db_type.setCurrentIndex(i)
                break
        self._host.setText(p.host)
        self._port.setValue(p.port)
        self._database.setText(p.database)
        self._username.setText(p.username)
        self._password.setText(p.password)
        self._timeout.setValue(p.connection_timeout)
        self._ssl.setChecked(p.ssl)
        self._ssl_ca.setText(p.ssl_ca)
        self._ssl_cert.setText(p.ssl_cert)
        self._ssl_key.setText(p.ssl_key)
        self._on_type_changed(self._db_type.currentIndex())

    # ── Result ────────────────────────────────────────────────────────────────

    @property
    def profile(self) -> ConnectionProfile:
        return self._profile