"""Configuration management with validation."""

import os
from dataclasses import dataclass, field
from pathlib import Path

from dotenv import load_dotenv

# Load environment variables from .env file
load_dotenv()


class ConfigurationError(Exception):
    """Raised when configuration is invalid."""

    pass


@dataclass
class Settings:
    """Application settings loaded from environment variables."""

    # LLM Configuration
    deepseek_api_key: str = field(
        default_factory=lambda: os.getenv("DEEPSEEK_API_KEY", "")
    )
    deepseek_base_url: str = field(
        default_factory=lambda: os.getenv(
            "DEEPSEEK_BASE_URL", "https://api.deepseek.com"
        )
    )
    model: str = field(
        default_factory=lambda: os.getenv("DEEPSEEK_MODEL", "deepseek-chat")
    )
    temperature: float = field(
        default_factory=lambda: float(os.getenv("TEMPERATURE", "0.2"))
    )

    # TMDB Configuration
    tmdb_api_key: str = field(default_factory=lambda: os.getenv("TMDB_API_KEY", ""))
    tmdb_base_url: str = field(
        default_factory=lambda: os.getenv(
            "TMDB_BASE_URL", "https://api.themoviedb.org/3"
        )
    )

    # Storage Configuration
    memory_file: str = field(
        default_factory=lambda: os.getenv("MEMORY_FILE", "memory.json")
    )

    # Security Configuration
    max_tool_iterations: int = field(
        default_factory=lambda: int(os.getenv("MAX_TOOL_ITERATIONS", "5"))
    )
    request_timeout: int = field(
        default_factory=lambda: int(os.getenv("REQUEST_TIMEOUT", "30"))
    )

    # Memory Configuration
    max_history_messages: int = field(
        default_factory=lambda: int(os.getenv("MAX_HISTORY_MESSAGES", "10"))
    )

    def __post_init__(self):
        """Validate settings after initialization."""
        self._validate()

    def _validate(self) -> None:
        """Validate configuration values."""
        # Validate temperature
        if not 0.0 <= self.temperature <= 2.0:
            raise ConfigurationError(
                f"Temperature must be between 0.0 and 2.0, got {self.temperature}"
            )

        # Validate max_tool_iterations
        if self.max_tool_iterations < 1 or self.max_tool_iterations > 20:
            raise ConfigurationError(
                f"max_tool_iterations must be between 1 and 20, got {self.max_tool_iterations}"
            )

        # Validate request_timeout
        if self.request_timeout < 1 or self.request_timeout > 300:
            raise ConfigurationError(
                f"request_timeout must be between 1 and 300 seconds, got {self.request_timeout}"
            )

        # Validate URLs
        if not self.deepseek_base_url.startswith(("http://", "https://")):
            raise ConfigurationError(
                f"Invalid deepseek_base_url: {self.deepseek_base_url}"
            )

        if not self.tmdb_base_url.startswith(("http://", "https://")):
            raise ConfigurationError(f"Invalid tmdb_base_url: {self.tmdb_base_url}")

        # Validate memory file path
        memory_path = Path(self.memory_file)
        if memory_path.exists() and not memory_path.is_file():
            raise ConfigurationError(
                f"memory_file exists but is not a file: {self.memory_file}"
            )

    def is_deepseek_configured(self) -> bool:
        """Check if DeepSeek API is properly configured."""
        return bool(self.deepseek_api_key and self.deepseek_base_url)

    def is_tmdb_configured(self) -> bool:
        """Check if TMDB API is properly configured."""
        return bool(self.tmdb_api_key and self.tmdb_base_url)


# Global settings instance
settings = Settings()