"""Scraper configuration with environment variable loading."""
from __future__ import annotations

import os
from dataclasses import dataclass
from typing import Self


@dataclass(frozen=True)
class ScraperConfig:
    """Configuration for the Rightmove scraper.

    Attributes:
        max_concurrent_requests: Maximum number of concurrent HTTP requests.
        request_delay_ms: Delay between requests in milliseconds.
        result_cap: Maximum results Rightmove returns per query (their limit).
        split_threshold: When results exceed this, split the query further.
        min_price_band: Minimum width of a price band (won't split below this).
        max_pages_per_query: Maximum pages to fetch per subquery (60 * 25 = 1500).
        proxy_url: Optional SOCKS proxy URL (e.g., socks5://localhost:9050 for Tor).
        slow_response_threshold: Response time threshold in seconds for throttle detection.
        enable_circuit_breaker: Whether to enable circuit breaker protection.
        circuit_breaker_failure_threshold: Number of consecutive failures to open circuit.
        circuit_breaker_recovery_timeout: Seconds to wait before testing recovery.
    """

    max_concurrent_requests: int = 5
    request_delay_ms: int = 100
    result_cap: int = 1500
    split_threshold: int = 1200  # Split when approaching cap
    min_price_band: int = 100  # Minimum band width in currency units
    max_pages_per_query: int = 60  # 60 * 25 = 1500 results max
    proxy_url: str | None = None
    slow_response_threshold: float = 10.0  # seconds
    enable_circuit_breaker: bool = True
    circuit_breaker_failure_threshold: int = 5
    circuit_breaker_recovery_timeout: float = 60.0

    @classmethod
    def from_env(cls) -> Self:
        """Load configuration from environment variables.

        Environment variables:
            RIGHTMOVE_MAX_CONCURRENT: Max concurrent requests (default: 5)
            RIGHTMOVE_REQUEST_DELAY_MS: Request delay in ms (default: 100)
            RIGHTMOVE_RESULT_CAP: Result cap per query (default: 1500)
            RIGHTMOVE_SPLIT_THRESHOLD: Split threshold (default: 1200)
            RIGHTMOVE_MIN_PRICE_BAND: Minimum price band width (default: 100)
            RIGHTMOVE_MAX_PAGES: Max pages per query (default: 60)
            RIGHTMOVE_PROXY_URL: SOCKS proxy URL (default: None)
            RIGHTMOVE_SLOW_RESPONSE_THRESHOLD: Slow response threshold in seconds (default: 10.0)
            RIGHTMOVE_ENABLE_CIRCUIT_BREAKER: Enable circuit breaker (default: True)
            RIGHTMOVE_CIRCUIT_BREAKER_FAILURES: Failures to open circuit (default: 5)
            RIGHTMOVE_CIRCUIT_BREAKER_TIMEOUT: Recovery timeout in seconds (default: 60.0)

        Returns:
            ScraperConfig instance with values from environment or defaults.
        """
        return cls(
            max_concurrent_requests=int(
                os.environ.get("RIGHTMOVE_MAX_CONCURRENT", "5")
            ),
            request_delay_ms=int(
                os.environ.get("RIGHTMOVE_REQUEST_DELAY_MS", "100")
            ),
            result_cap=int(os.environ.get("RIGHTMOVE_RESULT_CAP", "1500")),
            split_threshold=int(
                os.environ.get("RIGHTMOVE_SPLIT_THRESHOLD", "1200")
            ),
            min_price_band=int(
                os.environ.get("RIGHTMOVE_MIN_PRICE_BAND", "100")
            ),
            max_pages_per_query=int(
                os.environ.get("RIGHTMOVE_MAX_PAGES", "60")
            ),
            proxy_url=os.environ.get("RIGHTMOVE_PROXY_URL") or None,
            slow_response_threshold=float(
                os.environ.get("RIGHTMOVE_SLOW_RESPONSE_THRESHOLD", "10.0")
            ),
            enable_circuit_breaker=os.environ.get(
                "RIGHTMOVE_ENABLE_CIRCUIT_BREAKER", "true"
            ).lower() in ("true", "1", "yes"),
            circuit_breaker_failure_threshold=int(
                os.environ.get("RIGHTMOVE_CIRCUIT_BREAKER_FAILURES", "5")
            ),
            circuit_breaker_recovery_timeout=float(
                os.environ.get("RIGHTMOVE_CIRCUIT_BREAKER_TIMEOUT", "60.0")
            ),
        )