from app_class import AppClass
from config import Config
from cpufreq import cpuFreq, cpufreq  # type: ignore
from functools import cached_property
from mapping import governor_priority_mapping
from exceptions import GovernorNotFound
from typing import Optional


class Governor(AppClass):
    def __init__(self, _config: Config) -> None:
        super().__init__(_config)
        self.log.info("current governor is: %s", self.current_governor)

    @cached_property
    def _cpufreq(self) -> Optional[cpuFreq]:
        try:
            return cpuFreq()
        except cpufreq.CPUFreqErrorInit:
            self.log.warning("cpu architecture has no governor support")
        return None
    
    @property
    def current_governor(self) -> Optional[str]:
        if self._cpufreq is None:
            return None
        _governor = set(self._cpufreq.get_governors().values())
        _governor_to_return = list(_governor)[0]
        if len(_governor) == 0:
            raise GovernorNotFound("Unable to retrieve current governor")
        if len(_governor) > 1:
            self.log.error("multiple governors have been set, which is not expected.")
            # returning governor with highest priority based on performance
            for gov in _governor:
                if governor_priority_mapping[gov] < governor_priority_mapping[_governor_to_return]:
                    _governor_to_return == gov
        return _governor_to_return            
                  
    def set_governor(self, governor_name: str) -> None:
        self.log.debug(
            "setting cpu governor to %s by using command self._cpufreq.set_governors(%s)", 
            governor_name, governor_name
        )
        
        if self._config.testmode:
            self.log.warning("application is running in testmode, cpu governor not set")
            return None
        
        if self._cpufreq is None:
            return None
        
        if governor_name not in self._cpufreq.available_governors:
            self.log.error("governor %s not supported by cpu", governor_name)
            return None
        
        self._cpufreq.set_governors(governor_name)