"""
sn_basis/functions/variable_wrapper.py – QGIS-Variablen-Abstraktion
"""

from typing import Any

from sn_basis.functions.qgiscore_wrapper import QgsProject


# ---------------------------------------------------------
# Versuch: QgsExpressionContextUtils importieren
# ---------------------------------------------------------

try:
    from qgis.core import QgsExpressionContextUtils

    _HAS_QGIS_VARIABLES = True

# ---------------------------------------------------------
# Mock-Modus
# ---------------------------------------------------------

except Exception:
    _HAS_QGIS_VARIABLES = False

    class _MockVariableStore:
        global_vars: dict[str, str] = {}
        project_vars: dict[str, str] = {}

    class QgsExpressionContextUtils:
        @staticmethod
        def setGlobalVariable(name: str, value: str) -> None:
            _MockVariableStore.global_vars[name] = value

        @staticmethod
        def globalScope():
            class _Scope:
                def variable(self, name: str) -> str:
                    return _MockVariableStore.global_vars.get(name, "")

            return _Scope()

        @staticmethod
        def setProjectVariable(project: Any, name: str, value: str) -> None:
            _MockVariableStore.project_vars[name] = value

        @staticmethod
        def projectScope(project: Any):
            class _Scope:
                def variable(self, name: str) -> str:
                    return _MockVariableStore.project_vars.get(name, "")

            return _Scope()


# ---------------------------------------------------------
# Öffentliche API
# ---------------------------------------------------------

def get_variable(key: str, scope: str = "project") -> str:
    """
    Liest eine QGIS-Variable.

    :param key: Variablenname ohne Prefix
    :param scope: 'project' oder 'global'
    """
    var_name = f"sn_{key}"

    if scope == "project":
        project = QgsProject.instance()
        return (
            QgsExpressionContextUtils
            .projectScope(project)
            .variable(var_name)
            or ""
        )

    if scope == "global":
        return (
            QgsExpressionContextUtils
            .globalScope()
            .variable(var_name)
            or ""
        )

    raise ValueError("Scope muss 'project' oder 'global' sein.")


def set_variable(key: str, value: str, scope: str = "project") -> None:
    """
    Setzt eine QGIS-Variable.

    :param key: Variablenname ohne Prefix
    :param value: Wert
    :param scope: 'project' oder 'global'
    """
    var_name = f"sn_{key}"

    if scope == "project":
        project = QgsProject.instance()
        QgsExpressionContextUtils.setProjectVariable(
            project,
            var_name,
            value,
        )
        return

    if scope == "global":
        QgsExpressionContextUtils.setGlobalVariable(
            var_name,
            value,
        )
        return

    raise ValueError("Scope muss 'project' oder 'global' sein.")