use std::{convert::Infallible, fmt};

use axum::response::{IntoResponse, Response};
use bytes::BytesMut;
use http::StatusCode;
use http_body_util::Full;
use ruma::{
	api::{
		client::{
			error::ErrorKind::{
				Forbidden, GuestAccessForbidden, LimitExceeded, MissingToken, NotFound, ThreepidAuthFailed,
				ThreepidDenied, TooLarge, Unauthorized, Unknown, UnknownToken, Unrecognized, UserDeactivated,
				WrongRoomKeysVersion,
			},
			uiaa::{UiaaInfo, UiaaResponse},
		},
		OutgoingResponse,
	},
	OwnedServerName,
};
use thiserror::Error;

use crate::{debug_error, error};

#[derive(Error)]
pub enum Error {
	// std
	#[error("{0}")]
	Fmt(#[from] fmt::Error),
	#[error("I/O error: {0}")]
	Io(#[from] std::io::Error),
	#[error("{0}")]
	Utf8Error(#[from] std::str::Utf8Error),
	#[error("{0}")]
	FromUtf8Error(#[from] std::string::FromUtf8Error),
	#[error("{0}")]
	TryFromSliceError(#[from] std::array::TryFromSliceError),
	#[error("{0}")]
	TryFromIntError(#[from] std::num::TryFromIntError),
	#[error("{0}")]
	ParseIntError(#[from] std::num::ParseIntError),
	#[error("{0}")]
	ParseFloatError(#[from] std::num::ParseFloatError),

	// third-party
	#[error("Regex error: {0}")]
	Regex(#[from] regex::Error),
	#[error("Tracing filter error: {0}")]
	TracingFilter(#[from] tracing_subscriber::filter::ParseError),
	#[error("Image error: {0}")]
	Image(#[from] image::error::ImageError),
	#[error("Request error: {0}")]
	Reqwest(#[from] reqwest::Error),
	#[error("{0}")]
	Extension(#[from] axum::extract::rejection::ExtensionRejection),
	#[error("{0}")]
	Path(#[from] axum::extract::rejection::PathRejection),

	// ruma
	#[error("{0}")]
	Mxid(#[from] ruma::IdParseError),
	#[error("{0}: {1}")]
	BadRequest(ruma::api::client::error::ErrorKind, &'static str),
	#[error("from {0}: {1}")]
	Redaction(OwnedServerName, ruma::canonical_json::RedactionError),
	#[error("Remote server {0} responded with: {1}")]
	Federation(OwnedServerName, ruma::api::client::error::Error),
	#[error("{0} in {1}")]
	InconsistentRoomState(&'static str, ruma::OwnedRoomId),

	// conduwuit
	#[error("Arithmetic operation failed: {0}")]
	Arithmetic(&'static str),
	#[error("There was a problem with your configuration: {0}")]
	BadConfig(String),
	#[error("{0}")]
	BadDatabase(&'static str),
	#[error("{0}")]
	Database(String),
	#[error("{0}")]
	BadServerResponse(&'static str),
	#[error("{0}")]
	Conflict(&'static str), // This is only needed for when a room alias already exists
	#[error("uiaa")]
	Uiaa(UiaaInfo),

	// unique / untyped
	#[error("{0}")]
	Err(String),
}

impl Error {
	pub fn bad_database(message: &'static str) -> Self {
		error!("BadDatabase: {}", message);
		Self::BadDatabase(message)
	}

	pub fn bad_config(message: &str) -> Self {
		error!("BadConfig: {}", message);
		Self::BadConfig(message.to_owned())
	}

	/// Returns the Matrix error code / error kind
	#[inline]
	pub fn error_code(&self) -> ruma::api::client::error::ErrorKind {
		if let Self::Federation(_, error) = self {
			return error.error_kind().unwrap_or_else(|| &Unknown).clone();
		}

		match self {
			Self::BadRequest(kind, _) => kind.clone(),
			_ => Unknown,
		}
	}

	/// Sanitizes public-facing errors that can leak sensitive information.
	pub fn sanitized_error(&self) -> String {
		match self {
			Self::Database {
				..
			} => String::from("Database error occurred."),
			Self::Io {
				..
			} => String::from("I/O error occurred."),
			_ => self.to_string(),
		}
	}
}

impl From<Infallible> for Error {
	fn from(i: Infallible) -> Self { match i {} }
}

impl fmt::Debug for Error {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{self}") }
}

#[inline]
pub fn log(e: Error) {
	error!("{e}");
	drop(e);
}

#[inline]
pub fn debug_log(e: Error) {
	debug_error!("{e}");
	drop(e);
}

#[derive(Clone)]
pub struct RumaResponse<T>(pub T);

impl<T> From<T> for RumaResponse<T> {
	fn from(t: T) -> Self { Self(t) }
}

impl From<Error> for RumaResponse<UiaaResponse> {
	fn from(t: Error) -> Self { t.to_response() }
}

impl Error {
	pub fn to_response(&self) -> RumaResponse<UiaaResponse> {
		use ruma::api::client::error::{Error as RumaError, ErrorBody};

		if let Self::Uiaa(uiaainfo) = self {
			return RumaResponse(UiaaResponse::AuthResponse(uiaainfo.clone()));
		}

		if let Self::Federation(origin, error) = self {
			let mut error = error.clone();
			error.body = ErrorBody::Standard {
				kind: error.error_kind().unwrap_or_else(|| &Unknown).clone(),
				message: format!("Answer from {origin}: {error}"),
			};
			return RumaResponse(UiaaResponse::MatrixError(error));
		}

		let message = format!("{self}");
		let (kind, status_code) = match self {
			Self::BadRequest(kind, _) => (
				kind.clone(),
				match kind {
					WrongRoomKeysVersion {
						..
					}
					| Forbidden {
						..
					}
					| GuestAccessForbidden
					| ThreepidAuthFailed
					| UserDeactivated
					| ThreepidDenied => StatusCode::FORBIDDEN,
					Unauthorized
					| UnknownToken {
						..
					}
					| MissingToken => StatusCode::UNAUTHORIZED,
					NotFound | Unrecognized => StatusCode::NOT_FOUND,
					LimitExceeded {
						..
					} => StatusCode::TOO_MANY_REQUESTS,
					TooLarge => StatusCode::PAYLOAD_TOO_LARGE,
					_ => StatusCode::BAD_REQUEST,
				},
			),
			Self::Conflict(_) => (Unknown, StatusCode::CONFLICT),
			_ => (Unknown, StatusCode::INTERNAL_SERVER_ERROR),
		};

		RumaResponse(UiaaResponse::MatrixError(RumaError {
			body: ErrorBody::Standard {
				kind,
				message,
			},
			status_code,
		}))
	}
}

impl ::axum::response::IntoResponse for Error {
	fn into_response(self) -> ::axum::response::Response { self.to_response().into_response() }
}

impl<T: OutgoingResponse> IntoResponse for RumaResponse<T> {
	fn into_response(self) -> Response {
		match self.0.try_into_http_response::<BytesMut>() {
			Ok(res) => res.map(BytesMut::freeze).map(Full::new).into_response(),
			Err(_) => StatusCode::INTERNAL_SERVER_ERROR.into_response(),
		}
	}
}