"""
QAbstractTableModel that wraps a list of plain tuples (rows) for display
in a QTableView. Supports sorting and in-place data refresh.
"""
from PyQt6.QtCore import (
    QAbstractTableModel, QModelIndex, Qt, QSortFilterProxyModel
)
from PyQt6.QtGui import QColor, QFont

from app.config.theme import get_palette


class ResultTableModel(QAbstractTableModel):
    """Immutable result-set model — replaces data via set_data()."""

    @property
    def NULL_COLOR(self):
        return QColor(get_palette()["overlay"])
    NUM_ALIGN   = Qt.AlignmentFlag.AlignRight | Qt.AlignmentFlag.AlignVCenter
    TEXT_ALIGN  = Qt.AlignmentFlag.AlignLeft  | Qt.AlignmentFlag.AlignVCenter

    _NUMERIC_TYPES = (int, float)

    def __init__(self, parent=None):
        super().__init__(parent)
        self._columns: list = []
        self._rows:    list = []

    # ── Public API ────────────────────────────────────────────────────────────

    def set_data(self, columns: list, rows: list) -> None:
        self.beginResetModel()
        self._columns = list(columns)
        self._rows    = [tuple(r) for r in rows]
        self.endResetModel()

    def clear(self) -> None:
        self.set_data([], [])

    def get_row(self, row: int) -> tuple:
        return self._rows[row]

    def column_names(self) -> list:
        return list(self._columns)

    def export_csv(self, filepath: str, delimiter: str = ",") -> None:
        import csv
        with open(filepath, "w", newline="", encoding="utf-8") as f:
            writer = csv.writer(f, delimiter=delimiter)
            writer.writerow(self._columns)
            writer.writerows(self._rows)

    def export_json(self, filepath: str) -> None:
        import json
        records = [dict(zip(self._columns, row)) for row in self._rows]
        with open(filepath, "w", encoding="utf-8") as f:
            json.dump(records, f, indent=2, default=str)

    def export_sql(self, filepath: str, table_name: str = "table") -> None:
        with open(filepath, "w", encoding="utf-8") as f:
            cols = ", ".join(self._columns)
            for row in self._rows:
                vals = ", ".join(
                    "NULL" if v is None else f"'{str(v).replace(chr(39), chr(39)*2)}'"
                    for v in row
                )
                f.write(f"INSERT INTO {table_name} ({cols}) VALUES ({vals});\n")

    # ── QAbstractTableModel interface ─────────────────────────────────────────

    def rowCount(self, parent=QModelIndex()) -> int:
        return len(self._rows)

    def columnCount(self, parent=QModelIndex()) -> int:
        return len(self._columns)

    def headerData(self, section: int, orientation, role=Qt.ItemDataRole.DisplayRole):
        if role == Qt.ItemDataRole.DisplayRole:
            if orientation == Qt.Orientation.Horizontal:
                return self._columns[section] if section < len(self._columns) else ""
            else:
                return str(section + 1)
        if role == Qt.ItemDataRole.FontRole and orientation == Qt.Orientation.Horizontal:
            f = QFont()
            f.setBold(True)
            return f
        return None

    def data(self, index: QModelIndex, role=Qt.ItemDataRole.DisplayRole):
        if not index.isValid():
            return None
        row, col = index.row(), index.column()
        if row >= len(self._rows) or col >= len(self._columns):
            return None
        value = self._rows[row][col]

        if role == Qt.ItemDataRole.DisplayRole:
            if value is None:
                return "NULL"
            return str(value)

        if role == Qt.ItemDataRole.ForegroundRole and value is None:
            return self.NULL_COLOR

        if role == Qt.ItemDataRole.TextAlignmentRole:
            if isinstance(value, self._NUMERIC_TYPES):
                return int(self.NUM_ALIGN)
            return int(self.TEXT_ALIGN)

        if role == Qt.ItemDataRole.UserRole:
            return value   # raw Python value

        return None

    def flags(self, index: QModelIndex):
        return Qt.ItemFlag.ItemIsEnabled | Qt.ItemFlag.ItemIsSelectable