"""
Column definition dialog — used for both Add Column and Rename Column operations
in the Table Designer.
"""
from PyQt6.QtWidgets import (
    QDialog, QVBoxLayout, QHBoxLayout, QFormLayout,
    QLineEdit, QComboBox, QCheckBox, QDialogButtonBox, QLabel,
)
from PyQt6.QtCore import Qt


# Common SQL types offered in the dropdown (user can type anything)
_COMMON_TYPES = [
    "INT",
    "BIGINT",
    "SMALLINT",
    "TINYINT",
    "BOOLEAN",
    "FLOAT",
    "DOUBLE",
    "DECIMAL(10,2)",
    "VARCHAR(255)",
    "VARCHAR(100)",
    "CHAR(36)",
    "TEXT",
    "LONGTEXT",
    "DATE",
    "DATETIME",
    "TIMESTAMP",
    "TIME",
    "JSON",
    "BLOB",
    "BINARY(16)",
]


class ColumnDialog(QDialog):
    """
    Dialog for adding a new column or renaming an existing one.

    In rename mode only the Name field is shown; in add mode all fields appear.
    """

    def __init__(self, mode: str = "add", column_name: str = "",
                 db_type: str = "", parent=None):
        """
        Args:
            mode: "add" | "rename"
            column_name: pre-filled name (for rename, the old name)
            db_type: driver db_type string — used to tailor type suggestions
        """
        super().__init__(parent)
        self._mode = mode
        self._db_type = db_type

        self.setWindowTitle("Add Column" if mode == "add" else "Rename Column")
        self.setModal(True)
        self.setMinimumWidth(360)
        self._build_ui(column_name)

    # ── Properties ────────────────────────────────────────────────────────────

    @property
    def column_name(self) -> str:
        return self._name_edit.text().strip()

    @property
    def column_type(self) -> str:
        return self._type_combo.currentText().strip()

    @property
    def nullable(self) -> bool:
        return self._nullable_cb.isChecked()

    @property
    def default_value(self) -> str:
        return self._default_edit.text().strip()

    # ── UI ────────────────────────────────────────────────────────────────────

    def _build_ui(self, column_name: str):
        root = QVBoxLayout(self)

        form = QFormLayout()
        form.setLabelAlignment(Qt.AlignmentFlag.AlignRight)

        # Name
        self._name_edit = QLineEdit(column_name)
        self._name_edit.setPlaceholderText("column_name")
        form.addRow("Column name:", self._name_edit)

        if self._mode == "add":
            # Type
            self._type_combo = QComboBox()
            self._type_combo.setEditable(True)
            self._type_combo.addItems(_COMMON_TYPES)
            self._type_combo.setCurrentText("VARCHAR(255)")
            form.addRow("Data type:", self._type_combo)

            # Nullable
            self._nullable_cb = QCheckBox()
            self._nullable_cb.setChecked(True)
            form.addRow("Allow NULL:", self._nullable_cb)

            # Default
            self._default_edit = QLineEdit()
            self._default_edit.setPlaceholderText("optional default value")
            form.addRow("Default:", self._default_edit)
        else:
            # Stub widgets so properties don't crash in rename mode
            self._type_combo = QComboBox()
            self._nullable_cb = QCheckBox()
            self._nullable_cb.setChecked(True)
            self._default_edit = QLineEdit()

        root.addLayout(form)

        if self._mode == "add":
            note = QLabel(
                "<i>Changes are applied immediately via ALTER TABLE.</i>"
            )
            note.setWordWrap(True)
            root.addWidget(note)

        # Buttons
        btns = QDialogButtonBox(
            QDialogButtonBox.StandardButton.Ok |
            QDialogButtonBox.StandardButton.Cancel
        )
        btns.accepted.connect(self._accept)
        btns.rejected.connect(self.reject)
        root.addWidget(btns)

    def _accept(self):
        if not self.column_name:
            self._name_edit.setFocus()
            return
        if self._mode == "add" and not self.column_type:
            self._type_combo.setFocus()
            return
        self.accept()