import os
import re
from pathlib import Path
from typing import List, Optional
from pydantic import BaseModel, Field, field_validator
import yaml
from loguru import logger


class RegisterConfig(BaseModel):
    """Modbus Register Configuration"""
    address: int
    attribute: str
    name: str
    unit: str
    register_type: str
    data_type: str
    adaptor: str


class OutputConfig(BaseModel):
    """Output Configuration for Modbus Devices"""
    name: str
    enabled: bool = Field(default=True)
    scan_rate: Optional[int] = Field(default=60)
    publish_topic: str
    raw_output: Optional[bool] = Field(default=False)
    slave_id: int
    registers: List[RegisterConfig]

class InputConfig(BaseModel):
    """Input Configuration for Modbus Devices (MQTT -> Modbus)"""
    name: str
    enabled: bool = Field(default=True)
    subscribe_topic: str
    slave_id: int
    address: int
    register_type: str


class MqttConfig(BaseModel):
    """MQTT Configuration"""
    broker: str
    port: int


class ModbusConfig(BaseModel):
    """Modbus Configuration"""
    gateway: str


class GlobalConfig(BaseModel):
    """Global settings"""
    scan_interval: int
    log_level: str


class Config(BaseModel):
    """Main Configuration"""
    global_: GlobalConfig = Field(alias="global")
    mqtt: MqttConfig
    modbus: ModbusConfig
    input: List[InputConfig]
    output: List[OutputConfig]

    @classmethod
    def load_from_file(cls, config_path: Optional[str] = None) -> 'Config':
        """
        Load configuration from YAML file with environment variable substitution.
        
        Args:
            config_path: Path to config file. If None, uses CFG_FILE environment variable.
        
        Returns:
            Config instance
        """
        if config_path is None:
            config_path = os.getenv('CFG_FILE')
            if config_path is None:
                raise ValueError("Config path not provided and CFG_FILE environment variable not set")
        
        config_file = Path(config_path)
        if not config_file.exists():
            raise FileNotFoundError(f"Configuration file not found: {config_path}")
        
        # Read YAML file
        with open(config_file, 'r', encoding='utf-8') as f:
            yaml_content = f.read()
        
        # Parse YAML
        config_dict = yaml.safe_load(yaml_content)
        
        logger.info(f"Configuration loaded from: {config_path}")
        return cls(**config_dict)