"""Provider registry.

Concrete provider implementations live in the ``Provider`` package.  This module
is the single source of truth for discovery, metadata, and lifecycle helpers
for those plugins.
"""

from __future__ import annotations

import importlib
import pkgutil
import sys
from dataclasses import dataclass, field
from types import ModuleType
from typing import Any, Dict, Iterable, List, Optional, Sequence, Tuple, Type
from urllib.parse import urlparse

from SYS.logger import log, debug

from ProviderCore.base import FileProvider, Provider, SearchProvider, SearchResult
from Provider.soulseek import download_soulseek_file


@dataclass(frozen=True)
class ProviderInfo:
    """Metadata about a single provider entry."""

    canonical_name: str
    provider_class: Type[Provider]
    module: str
    alias_names: Tuple[str, ...] = field(default_factory=tuple)

    @property
    def supports_search(self) -> bool:
        return self.provider_class.search is not Provider.search

    @property
    def supports_upload(self) -> bool:
        return self.provider_class.upload is not Provider.upload


class ProviderRegistry:
    """Handles discovery, registration, and lookup of provider classes."""

    def __init__(self, package_name: str) -> None:
        self.package_name = (package_name or "").strip()
        self._infos: Dict[str, ProviderInfo] = {}
        self._lookup: Dict[str, ProviderInfo] = {}
        self._modules: set[str] = set()
        self._discovered = False

    def _normalize(self, value: Any) -> str:
        return str(value or "").strip().lower()

    def _candidate_names(self,
                         provider_class: Type[Provider],
                         override_name: Optional[str]) -> List[str]:
        names: List[str] = []
        seen: set[str] = set()

        def _add(value: Any) -> None:
            text = str(value or "").strip()
            normalized = text.lower()
            if not text or normalized in seen:
                return
            seen.add(normalized)
            names.append(text)

        if override_name:
            _add(override_name)
        else:
            # Use class name as the primary canonical name
            _add(getattr(provider_class, "__name__", None))
            _add(getattr(provider_class, "PROVIDER_NAME", None))
            _add(getattr(provider_class, "NAME", None))

        for alias in getattr(provider_class, "PROVIDER_ALIASES", ()) or ():
            _add(alias)

        return names

    def register(
        self,
        provider_class: Type[Provider],
        *,
        override_name: Optional[str] = None,
        extra_aliases: Optional[Sequence[str]] = None,
        module_name: Optional[str] = None,
        replace: bool = False,
    ) -> ProviderInfo:
        """Register a provider class with canonical and alias names."""
        candidates = self._candidate_names(provider_class, override_name)
        if not candidates:
            raise ValueError("provider name candidates are required")

        canonical = self._normalize(candidates[0])
        if not canonical:
            raise ValueError("provider name must not be empty")

        alias_names: List[str] = []
        alias_seen: set[str] = set()

        for candidate in candidates[1:]:
            normalized = self._normalize(candidate)
            if not normalized or normalized == canonical or normalized in alias_seen:
                continue
            alias_seen.add(normalized)
            alias_names.append(normalized)

        for alias in extra_aliases or ():
            normalized = self._normalize(alias)
            if not normalized or normalized == canonical or normalized in alias_seen:
                continue
            alias_seen.add(normalized)
            alias_names.append(normalized)

        info = ProviderInfo(
            canonical_name=canonical,
            provider_class=provider_class,
            module=module_name or getattr(provider_class, "__module__", "") or "",
            alias_names=tuple(alias_names),
        )

        existing = self._infos.get(canonical)
        if existing is not None and not replace:
            return existing

        self._infos[canonical] = info
        for lookup in (canonical,) + tuple(alias_names):
            self._lookup[lookup] = info
        return info

    def _register_module(self, module: ModuleType) -> None:
        module_name = getattr(module, "__name__", "")
        if not module_name or module_name in self._modules:
            return
        self._modules.add(module_name)

        for attr in dir(module):
            candidate = getattr(module, attr)
            if not isinstance(candidate, type):
                continue
            if not issubclass(candidate, Provider):
                continue
            if candidate in {Provider, SearchProvider, FileProvider}:
                continue
            if getattr(candidate, "__module__", "") != module_name:
                continue
            try:
                self.register(candidate, module_name=module_name)
            except Exception as exc:
                log(f"[provider] Failed to register {module_name}.{candidate.__name__}: {exc}", file=sys.stderr)

    def discover(self) -> None:
        """Import and register providers from the package."""

        if self._discovered or not self.package_name:
            return
        self._discovered = True

        try:
            package = importlib.import_module(self.package_name)
        except Exception as exc:
            log(f"[provider] Failed to import package {self.package_name}: {exc}", file=sys.stderr)
            return

        self._register_module(package)
        package_path = getattr(package, "__path__", None)
        if not package_path:
            return

        for finder, module_name, _ in pkgutil.iter_modules(package_path):
            if module_name.startswith("_"):
                continue
            module_path = f"{self.package_name}.{module_name}"
            try:
                module = importlib.import_module(module_path)
            except Exception as exc:
                log(f"[provider] Failed to load {module_path}: {exc}", file=sys.stderr)
                continue
            self._register_module(module)

    def get(self, name: str) -> Optional[ProviderInfo]:
        self.discover()
        if not name:
            return None
        return self._lookup.get(self._normalize(name))

    def iter_providers(self) -> Iterable[ProviderInfo]:
        self.discover()
        return tuple(self._infos.values())

    def has_name(self, name: str) -> bool:
        return self.get(name) is not None

    def _sync_subclasses(self) -> None:
        """Walk all Provider subclasses in memory and register them."""
        def _walk(cls: Type[Provider]) -> None:
            for sub in cls.__subclasses__():
                if sub in {SearchProvider, FileProvider}:
                    _walk(sub)
                    continue
                try:
                    self.register(sub)
                except Exception:
                    pass
                _walk(sub)
        _walk(Provider)

REGISTRY = ProviderRegistry("Provider")
REGISTRY.discover()
REGISTRY._sync_subclasses()


def register_provider(
    provider_class: Type[Provider],
    *,
    name: Optional[str] = None,
    aliases: Optional[Sequence[str]] = None,
    module_name: Optional[str] = None,
    replace: bool = False,
) -> ProviderInfo:
    """Register a provider class from tests or third-party packages."""

    return REGISTRY.register(
        provider_class,
        override_name=name,
        extra_aliases=aliases,
        module_name=module_name,
        replace=replace,
    )


def get_provider_class(name: str) -> Optional[Type[Provider]]:
    info = REGISTRY.get(name)
    if info is None:
        return None
    return info.provider_class


def selection_auto_stage_for_table(
    table_type: str,
    stage_args: Optional[Sequence[str]] = None,
) -> Optional[list[str]]:
    t = str(table_type or "").strip().lower()
    if not t:
        return None

    provider_key = t.split(".", 1)[0] if "." in t else t
    provider_class = get_provider_class(provider_key) or get_provider_class(t)
    if provider_class is None:
        return None

    try:
        return provider_class.selection_auto_stage(t, stage_args)
    except Exception:
        return None


def is_known_provider_name(name: str) -> bool:
    return REGISTRY.has_name(name)


def _supports_search(provider: Provider) -> bool:
    return provider.__class__.search is not Provider.search


def _supports_upload(provider: Provider) -> bool:
    return provider.__class__.upload is not Provider.upload


def _provider_url_patterns(provider_class: Type[Provider]) -> Sequence[str]:
    try:
        return list(provider_class.url_patterns())
    except Exception:
        return []


def get_provider(name: str, config: Optional[Dict[str, Any]] = None) -> Optional[Provider]:
    info = REGISTRY.get(name)
    if info is None:
        debug(f"[provider] Unknown provider: {name}")
        return None

    try:
        provider = info.provider_class(config)
        if not provider.validate():
            debug(f"[provider] Provider '{name}' is not available")
            return None
        return provider
    except Exception as exc:
        debug(f"[provider] Error initializing '{name}': {exc}")
        return None


def list_providers(config: Optional[Dict[str, Any]] = None) -> Dict[str, bool]:
    availability: Dict[str, bool] = {}
    for info in REGISTRY.iter_providers():
        try:
            provider = info.provider_class(config)
            availability[info.canonical_name] = provider.validate()
        except Exception:
            availability[info.canonical_name] = False
    return availability


def get_search_provider(name: str,
                        config: Optional[Dict[str, Any]] = None) -> Optional[SearchProvider]:
    provider = get_provider(name, config)
    if provider is None:
        return None
    if not _supports_search(provider):
        debug(f"[provider] Provider '{name}' does not support search")
        return None
    return provider  # type: ignore[return-value]


def list_search_providers(config: Optional[Dict[str, Any]] = None) -> Dict[str, bool]:
    availability: Dict[str, bool] = {}
    for info in REGISTRY.iter_providers():
        try:
            provider = info.provider_class(config)
            availability[info.canonical_name] = bool(
                provider.validate() and info.supports_search
            )
        except Exception:
            availability[info.canonical_name] = False
    return availability


def get_file_provider(name: str,
                      config: Optional[Dict[str, Any]] = None) -> Optional[FileProvider]:
    provider = get_provider(name, config)
    if provider is None:
        return None
    if not _supports_upload(provider):
        debug(f"[provider] Provider '{name}' does not support upload")
        return None
    return provider  # type: ignore[return-value]


def list_file_providers(config: Optional[Dict[str, Any]] = None) -> Dict[str, bool]:
    availability: Dict[str, bool] = {}
    for info in REGISTRY.iter_providers():
        try:
            provider = info.provider_class(config)
            availability[info.canonical_name] = bool(
                provider.validate() and info.supports_upload
            )
        except Exception:
            availability[info.canonical_name] = False
    return availability


def match_provider_name_for_url(url: str) -> Optional[str]:
    raw_url = str(url or "").strip()
    raw_url_lower = raw_url.lower()
    try:
        parsed = urlparse(raw_url)
        host = (parsed.hostname or "").strip().lower()
        path = (parsed.path or "").strip()
    except Exception:
        host = ""
        path = ""

    def _norm_host(h: str) -> str:
        h_norm = str(h or "").strip().lower()
        if h_norm.startswith("www."):
            h_norm = h_norm[4:]
        return h_norm

    host_norm = _norm_host(host)

    if host_norm:
        if host_norm == "openlibrary.org" or host_norm.endswith(".openlibrary.org"):
            return "openlibrary" if REGISTRY.has_name("openlibrary") else None

        if host_norm == "archive.org" or host_norm.endswith(".archive.org"):
            low_path = str(path or "").lower()
            is_borrowish = (
                low_path.startswith("/borrow/")
                or low_path.startswith("/stream/")
                or low_path.startswith("/services/loans/")
                or "/services/loans/" in low_path
            )
            if is_borrowish:
                return "openlibrary" if REGISTRY.has_name("openlibrary") else None
            return "internetarchive" if REGISTRY.has_name("internetarchive") else None

    for info in REGISTRY.iter_providers():
        domains = _provider_url_patterns(info.provider_class)
        if not domains:
            continue
        for domain in domains:
            dom_raw = str(domain or "").strip()
            dom = dom_raw.lower()
            if not dom:
                continue
            if "://" in dom or dom.startswith("magnet:"):
                if raw_url_lower.startswith(dom):
                    return info.canonical_name
                continue

            dom_norm = _norm_host(dom)
            if not dom_norm or not host_norm:
                continue
            if host_norm == dom_norm or host_norm.endswith("." + dom_norm):
                return info.canonical_name

    return None


def provider_inline_query_choices(
    provider_name: str,
    field_name: str,
    config: Optional[Dict[str, Any]] = None,
) -> List[str]:
    """Return provider-declared inline query choices for a field (e.g., system:GBA).

    Providers can expose a mapping via ``QUERY_ARG_CHOICES`` (preferred) or
    ``INLINE_QUERY_FIELD_CHOICES`` / ``inline_query_field_choices()``. The helper
    keeps completion logic simple and reusable.
    This helper keeps completion logic simple and reusable.
    """

    pname = str(provider_name or "").strip().lower()
    field = str(field_name or "").strip().lower()
    if not pname or not field:
        return []

    provider = get_search_provider(pname, config)
    if provider is None:
        provider = get_provider(pname, config)
    if provider is None:
        return []

    def _normalize_choice_entry(entry: Any) -> Optional[Dict[str, Any]]:
        if entry is None:
            return None
        if isinstance(entry, dict):
            value = entry.get("value")
            text = entry.get("text") or entry.get("label") or value
            aliases = entry.get("alias") or entry.get("aliases") or []
            value_str = str(value) if value is not None else (str(text) if text is not None else None)
            text_str = str(text) if text is not None else value_str
            if not value_str or not text_str:
                return None
            alias_list = [str(a) for a in aliases if a is not None]
            return {"value": value_str, "text": text_str, "aliases": alias_list}
        # string/other primitives
        return {"value": str(entry), "text": str(entry), "aliases": []}

    def _collect_mapping(p) -> Dict[str, List[Dict[str, Any]]]:
        mapping: Dict[str, List[Dict[str, Any]]] = {}
        base = getattr(p, "QUERY_ARG_CHOICES", None)
        if not isinstance(base, dict):
            base = getattr(p, "INLINE_QUERY_FIELD_CHOICES", None)
        if isinstance(base, dict):
            for k, v in base.items():
                normalized: List[Dict[str, Any]] = []
                seq = v
                try:
                    if callable(seq):
                        seq = seq()
                except Exception:
                    seq = v
                if isinstance(seq, dict):
                    seq = seq.get("choices") or seq.get("values") or seq
                if isinstance(seq, (list, tuple, set)):
                    for entry in seq:
                        n = _normalize_choice_entry(entry)
                        if n:
                            normalized.append(n)
                if normalized:
                    mapping[str(k).strip().lower()] = normalized
        try:
            fn = getattr(p, "inline_query_field_choices", None)
            if callable(fn):
                extra = fn()
                if isinstance(extra, dict):
                    for k, v in extra.items():
                        normalized: List[Dict[str, Any]] = []
                        seq = v
                        try:
                            if callable(seq):
                                seq = seq()
                        except Exception:
                            seq = v
                        if isinstance(seq, dict):
                            seq = seq.get("choices") or seq.get("values") or seq
                        if isinstance(seq, (list, tuple, set)):
                            for entry in seq:
                                n = _normalize_choice_entry(entry)
                                if n:
                                    normalized.append(n)
                        if normalized:
                            mapping[str(k).strip().lower()] = normalized
        except Exception:
            pass
        return mapping

    try:
        mapping = _collect_mapping(provider)
        if not mapping:
            return []

        entries = mapping.get(field, [])
        if not entries:
            return []

        seen: set[str] = set()
        out: List[str] = []
        for entry in entries:
            text = entry.get("text") or entry.get("value")
            if not text:
                continue
            text_str = str(text)
            if text_str in seen:
                continue
            seen.add(text_str)
            out.append(text_str)
            for alias in entry.get("aliases", []):
                alias_str = str(alias)
                if alias_str and alias_str not in seen:
                    seen.add(alias_str)
                    out.append(alias_str)
        return out
    except Exception:
        return []


def get_provider_for_url(url: str,
                         config: Optional[Dict[str, Any]] = None) -> Optional[Provider]:
    name = match_provider_name_for_url(url)
    if not name:
        return None
    return get_provider(name, config)


def resolve_inline_filters(
    provider: Provider,
    inline_args: Dict[str, Any],
    *,
    field_transforms: Optional[Dict[str, Any]] = None,
) -> Dict[str, str]:
    """Map inline query args to provider filter values using declared choices.

    - Uses provider's inline choice mapping (value/text/aliases) to resolve user text.
    - Applies optional per-field transforms (e.g., str.upper).
    - Returns normalized filters suitable for provider.search.
    """

    filters: Dict[str, str] = {}
    if not inline_args:
        return filters

    mapping = _collect_mapping(provider)
    transforms = field_transforms or {}

    for raw_key, raw_val in inline_args.items():
        if raw_val is None:
            continue
        key = str(raw_key or "").strip().lower()
        val_str = str(raw_val).strip()
        if not key or not val_str:
            continue

        entries = mapping.get(key, [])
        resolved: Optional[str] = None
        val_lower = val_str.lower()
        for entry in entries:
            text = str(entry.get("text") or "").strip()
            value = str(entry.get("value") or "").strip()
            aliases = [str(a).strip() for a in entry.get("aliases", []) if a is not None]
            if val_lower in {text.lower(), value.lower()} or val_lower in {a.lower() for a in aliases}:
                resolved = value or text or val_str
                break

        if resolved is None:
            resolved = val_str

        transform = transforms.get(key)
        if callable(transform):
            try:
                resolved = transform(resolved)
            except Exception:
                pass
        if resolved:
            filters[key] = str(resolved)

    return filters


__all__ = [
    "ProviderInfo",
    "Provider",
    "SearchProvider",
    "FileProvider",
    "SearchResult",
    "register_provider",
    "get_provider",
    "list_providers",
    "get_search_provider",
    "list_search_providers",
    "get_file_provider",
    "list_file_providers",
    "match_provider_name_for_url",
    "get_provider_for_url",
    "get_provider_class",
    "selection_auto_stage_for_table",
    "download_soulseek_file",
    "provider_inline_query_choices",
]