from pathlib import Path
from typing import Annotated
from functools import lru_cache
from urllib.parse import urlparse
from dataclasses import dataclass, fields

from msgspec import Struct, Meta, convert, ValidationError

from scrapling.core._types import (
    Any,
    Dict,
    List,
    Set,
    Tuple,
    Optional,
    Callable,
    Sequence,
    overload,
    SetCookieParam,
    SelectorWaitStates,
)
from scrapling.engines.toolbelt.proxy_rotation import ProxyRotator
from scrapling.engines.toolbelt.navigation import construct_proxy_dict
from scrapling.engines._browsers._types import PlaywrightFetchParams, StealthFetchParams


# Custom validators for msgspec
@lru_cache(8)
def _is_invalid_file_path(value: str) -> bool | str:  # pragma: no cover
    """Fast file path validation"""
    path = Path(value)
    if not path.exists():
        return f"Init script path not found: {value}"
    if not path.is_file():
        return f"Init script is not a file: {value}"
    if not path.is_absolute():
        return f"Init script is not a absolute path: {value}"
    return False


@lru_cache(2)
def _is_invalid_cdp_url(cdp_url: str) -> bool | str:
    """Fast CDP URL validation"""
    if not cdp_url.startswith(("ws://", "wss://")):
        return "CDP URL must use 'ws://' or 'wss://' scheme"

    netloc = urlparse(cdp_url).netloc
    if not netloc:  # pragma: no cover
        return "Invalid hostname for the CDP URL"
    return False


# Type aliases for cleaner annotations
PagesCount = Annotated[int, Meta(ge=1, le=50)]
RetriesCount = Annotated[int, Meta(ge=1, le=10)]
Seconds = Annotated[int, float, Meta(ge=0)]


class PlaywrightConfig(Struct, kw_only=True, frozen=False, weakref=True):
    """Configuration struct for validation"""

    max_pages: PagesCount = 1
    headless: bool = True
    disable_resources: bool = False
    network_idle: bool = False
    load_dom: bool = True
    wait_selector: Optional[str] = None
    wait_selector_state: SelectorWaitStates = "attached"
    cookies: Sequence[SetCookieParam] | None = []
    google_search: bool = True
    wait: Seconds = 0
    timezone_id: str | None = ""
    page_action: Optional[Callable] = None
    proxy: Optional[str | Dict[str, str] | Tuple] = None  # The default value for proxy in Playwright's source is `None`
    proxy_rotator: Optional[ProxyRotator] = None
    extra_headers: Optional[Dict[str, str]] = None
    timeout: Seconds = 30000
    init_script: Optional[str] = None
    user_data_dir: str = ""
    selector_config: Optional[Dict] = {}
    additional_args: Optional[Dict] = {}
    locale: str | None = None
    real_chrome: bool = False
    cdp_url: Optional[str] = None
    useragent: Optional[str] = None
    extra_flags: Optional[List[str]] = None
    blocked_domains: Optional[Set[str]] = None
    retries: RetriesCount = 3
    retry_delay: Seconds = 1

    def __post_init__(self):  # pragma: no cover
        """Custom validation after msgspec validation"""
        if self.page_action and not callable(self.page_action):
            raise TypeError(f"page_action must be callable, got {type(self.page_action).__name__}")
        if self.proxy and self.proxy_rotator:
            raise ValueError(
                "Cannot use 'proxy_rotator' together with 'proxy'. "
                "Use either a static proxy or proxy rotation, not both."
            )
        if self.proxy:
            self.proxy = construct_proxy_dict(self.proxy)
        if self.cdp_url:
            cdp_msg = _is_invalid_cdp_url(self.cdp_url)
            if cdp_msg:
                raise ValueError(cdp_msg)

        if not self.cookies:
            self.cookies = []
        if not self.extra_flags:
            self.extra_flags = []
        if not self.selector_config:
            self.selector_config = {}
        if not self.additional_args:
            self.additional_args = {}

        if self.init_script is not None:
            validation_msg = _is_invalid_file_path(self.init_script)
            if validation_msg:
                raise ValueError(validation_msg)


class StealthConfig(PlaywrightConfig, kw_only=True, frozen=False, weakref=True):
    allow_webgl: bool = True
    hide_canvas: bool = False
    block_webrtc: bool = False
    solve_cloudflare: bool = False

    def __post_init__(self):
        """Custom validation after msgspec validation"""
        super(StealthConfig, self).__post_init__()
        # Cloudflare timeout adjustment
        if self.solve_cloudflare and self.timeout < 60_000:
            self.timeout = 60_000


@dataclass
class _fetch_params:
    """A dataclass of all parameters used by `fetch` calls"""

    google_search: bool
    timeout: Seconds
    wait: Seconds
    page_action: Optional[Callable]
    extra_headers: Optional[Dict[str, str]]
    disable_resources: bool
    wait_selector: Optional[str]
    wait_selector_state: SelectorWaitStates
    network_idle: bool
    load_dom: bool
    blocked_domains: Optional[Set[str]]
    solve_cloudflare: bool
    selector_config: Dict


def validate_fetch(
    method_kwargs: Dict | PlaywrightFetchParams | StealthFetchParams,
    session: Any,
    model: type[PlaywrightConfig] | type[StealthConfig],
) -> _fetch_params:  # pragma: no cover
    result: Dict[str, Any] = {}
    overrides: Dict[str, Any] = {}
    kwargs_dict: Dict[str, Any] = dict(method_kwargs)

    # Get all field names that _fetch_params needs
    fetch_param_fields = {f.name for f in fields(_fetch_params)}

    for key in fetch_param_fields:
        if key in kwargs_dict:
            overrides[key] = kwargs_dict[key]
        elif hasattr(session, "_config") and hasattr(session._config, key):
            result[key] = getattr(session._config, key)

    if overrides:
        validated_config = validate(overrides, model)
        # Extract ONLY the fields that were actually overridden (not all fields)
        # This prevents validated defaults from overwriting session config values
        validated_dict = {
            field: getattr(validated_config, field) for field in overrides.keys() if hasattr(validated_config, field)
        }

        # Preserve solve_cloudflare if the user explicitly provided it, even if the model doesn't have it
        if "solve_cloudflare" in overrides:
            validated_dict["solve_cloudflare"] = overrides["solve_cloudflare"]

        # Start with session defaults, then overwrite with validated overrides
        result.update(validated_dict)

    # solve_cloudflare defaults to False for models that don't have it (PlaywrightConfig)
    result.setdefault("solve_cloudflare", False)
    result.setdefault("blocked_domains", None)

    return _fetch_params(**result)


# Cache default values for each model to reduce validation overhead
models_default_values = {}

for _model in (StealthConfig, PlaywrightConfig):
    _defaults = {}
    if hasattr(_model, "__struct_defaults__") and hasattr(_model, "__struct_fields__"):
        for field_name, default_value in zip(_model.__struct_fields__, _model.__struct_defaults__):  # type: ignore
            # Skip factory defaults - these are msgspec._core.Factory instances
            if type(default_value).__name__ != "Factory":
                _defaults[field_name] = default_value

    models_default_values[_model.__name__] = _defaults.copy()


def _filter_defaults(params: Dict, model: str) -> Dict:
    """Filter out parameters that match their default values to reduce validation overhead."""
    defaults = models_default_values[model]
    return {k: v for k, v in params.items() if k not in defaults or v != defaults[k]}


@overload
def validate(params: Dict, model: type[StealthConfig]) -> StealthConfig: ...


@overload
def validate(params: Dict, model: type[PlaywrightConfig]) -> PlaywrightConfig: ...


def validate(params: Dict, model: type[PlaywrightConfig] | type[StealthConfig]) -> PlaywrightConfig | StealthConfig:
    try:
        # Filter out params with the default values (no need to validate them) to speed up validation
        filtered = _filter_defaults(params, model.__name__)
        return convert(filtered, model)
    except ValidationError as e:
        raise TypeError(f"Invalid argument type: {e}") from e
