from typing import Any

from discord import Guild
from pydantic import BaseModel, ConfigDict, field_validator

from ..config import config

SUPPORTED_PROVIDER_SERVICES = ["github", "gitlab", "forgejo"]


class UnsupportedServiceError(Exception):
    """Custom exception for unsupported provider services."""

    pass


class Provider(BaseModel):
    """Model for a provider configuration.

    Attributes:
        id (str): The ID of the provider. This should usually be the same as the URl, just without the scheme (i.e. https://).
        url (str): The URL of the provider.
        service (str): The service type of the provider (e.g., `github`, `gitlab`, `forgejo`). Must be one of the supported services.
        token (str): An optional API token for the provider. If not provided, unauthenticated requests will be used.
        guild (Guild | None): The Discord guild associated with the provider. If `None`, the provider is considered a global provider.

    Properties:
        api_url (str): The API URL for the provider. This is typically the base URL with an API path appended.
        favicon_url (str): The URL to the provider's favicon. This is typically the base URL with a favicon path appended.

    Methods:
        to_config: Save the provider to Red's configuration. Saves to guilds if the `guild` class attribute is not `None`.

    Class Methods:
        from_config: Create a Provider instance from the Red configuration. Checks both global and guild providers, prioritizing guild providers.
        fetch_all: Fetch all providers from the Red configuration. Checks both global and guild providers
    """

    model_config = ConfigDict(arbitrary_types_allowed=True)

    id: str
    url: str
    service: str
    token: str | None = None
    guild: Guild | None = None

    @field_validator("service")
    @classmethod
    def _validate_provider(cls, value: Any) -> Any:
        if value not in SUPPORTED_PROVIDER_SERVICES:
            raise UnsupportedServiceError("Provider service '%s' is not supported." % value)
        return value

    @property
    def api_url(self) -> str:
        """Return the API URL for the provider. This is typically the base URL with an API path appended."""
        match self.service:
            case "github":
                if self.url == "https://github.com":
                    return "https://api.github.com"
                return self.url.rstrip("/") + "/api/v3"
            case "gitlab":
                return self.url.rstrip("/") + "/api/v4"
            case "forgejo":
                return self.url.rstrip("/") + "/api/v1"
            case _:
                raise UnsupportedServiceError("Unsupported provider service:' '%s'" % self.service)

    @property
    def graphql_url(self) -> str:
        """Return the GraphQL URL for the provider. This is typically the base URL with a GraphQL path appended."""
        match self.service:
            case "github":
                if self.url == "https://github.com":
                    return "https://api.github.com/graphql"
                return self.url.rstrip("/") + "/api/graphql"
            case "gitlab":
                return self.url.rstrip("/") + "/api/graphql"
            case "forgejo":
                raise ValueError("Forgejo does not support GraphQL.")
            case _:
                raise UnsupportedServiceError("Unsupported provider service:' '%s'" % self.service)

    @property
    def favicon_url(self) -> str:
        """Return the URL to the provider's favicon. This is typically the base URL with a favicon path appended."""
        if self.service == "github":
            # GitHub's favicon is *actually* an ico, and Discord can't embed those
            return self.url.rstrip("/") + "/apple-touch-icon.png"
        return self.url.rstrip("/") + "/favicon.ico"

    async def to_config(self) -> None:
        """Save the provider to Red's configuration. Saves to guilds if the `guild` class attribute is not `None`."""
        if self.guild:
            providers = await config.guild(self.guild).providers()
        else:
            providers = await config.global_providers()

        for provider in providers:
            if provider["url"] == self.url:
                provider["token"] = self.token

        if not any(provider["url"] == self.url for provider in providers):
            providers.append(self.model_dump(mode="json", exclude={"guild"}))

        if self.guild:
            await config.guild(self.guild).providers.set(providers)
        else:
            await config.global_providers.set(providers)

    @classmethod
    async def from_config(cls, provider_id: str, guild: Guild | None = None) -> "Provider":
        """Create a Provider instance from the Red configuration. Checks both global and guild providers, prioritizing guild providers."""
        if guild:
            guild_providers = await config.guild(guild).providers()
            for provider in guild_providers:
                if provider["id"] == provider_id:
                    return cls(guild=guild, **provider)

        providers = await config.global_providers()
        for provider in providers:
            if provider["id"] == provider_id:
                return cls(guild=None, **provider)
        raise ValueError("No provider found for ID: %s" % provider_id)

    @classmethod
    async def fetch_all(cls, guild: Guild | None = None) -> tuple["Provider"]:
        """Fetch all providers from the Red configuration. Checks both global and guild providers."""
        providers_list = []

        if guild:
            guild_providers = await config.guild(guild).providers()
            for provider in guild_providers:
                providers_list.extend((cls(guild=guild, **provider),))

        global_providers = await config.global_providers()
        for provider in global_providers:
            providers_list.extend((cls(guild=None, **provider),))

        return tuple(providers_list)