use serde::{Deserialize, Serialize};
use std::{
  fmt,
  fmt::{Debug, Display},
};
use tracing_error::SpanTrace;
#[cfg(feature = "full")]
use ts_rs::TS;

pub type LemmyResult<T> = Result<T, LemmyError>;

pub struct LemmyError {
  pub error_type: LemmyErrorType,
  pub inner: anyhow::Error,
  pub context: SpanTrace,
}

/// Maximum number of items in an array passed as API parameter. See [[LemmyErrorType::TooManyItems]]
pub const MAX_API_PARAM_ELEMENTS: usize = 1000;

impl<T> From<T> for LemmyError
where
  T: Into<anyhow::Error>,
{
  fn from(t: T) -> Self {
    let cause = t.into();
    LemmyError {
      error_type: LemmyErrorType::Unknown(format!("{}", &cause)),
      inner: cause,
      context: SpanTrace::capture(),
    }
  }
}

impl Debug for LemmyError {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
    f.debug_struct("LemmyError")
      .field("message", &self.error_type)
      .field("inner", &self.inner)
      .field("context", &self.context)
      .finish()
  }
}

impl Display for LemmyError {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "{}: ", &self.error_type)?;
    // print anyhow including trace
    // https://docs.rs/anyhow/latest/anyhow/struct.Error.html#display-representations
    // this will print the anyhow trace (only if it exists)
    // and if RUST_BACKTRACE=1, also a full backtrace
    writeln!(f, "{:?}", self.inner)?;
    fmt::Display::fmt(&self.context, f)
  }
}

impl actix_web::error::ResponseError for LemmyError {
  fn status_code(&self) -> http::StatusCode {
    if self.error_type == LemmyErrorType::IncorrectLogin {
      return http::StatusCode::UNAUTHORIZED;
    }
    match self.inner.downcast_ref::<diesel::result::Error>() {
      Some(diesel::result::Error::NotFound) => http::StatusCode::NOT_FOUND,
      _ => http::StatusCode::BAD_REQUEST,
    }
  }

  fn error_response(&self) -> actix_web::HttpResponse {
    actix_web::HttpResponse::build(self.status_code()).json(&self.error_type)
  }
}

#[derive(Display, Debug, Serialize, Deserialize, Clone, PartialEq, EnumIter)]
#[cfg_attr(feature = "full", derive(TS))]
#[cfg_attr(feature = "full", ts(export))]
#[serde(tag = "error", content = "message", rename_all = "snake_case")]
// TODO: order these based on the crate they belong to (utils, federation, db, api)
pub enum LemmyErrorType {
  ReportReasonRequired,
  ReportTooLong,
  NotAModerator,
  NotAnAdmin,
  CantBlockYourself,
  CantBlockAdmin,
  CouldntUpdateUser,
  PasswordsDoNotMatch,
  EmailNotVerified,
  EmailRequired,
  CouldntUpdateComment,
  CouldntUpdatePrivateMessage,
  CannotLeaveAdmin,
  NoLinesInHtml,
  SiteMetadataPageIsNotDoctypeHtml,
  PictrsResponseError(String),
  PictrsPurgeResponseError(String),
  PictrsCachingDisabled,
  ImageUrlMissingPathSegments,
  ImageUrlMissingLastPathSegment,
  PictrsApiKeyNotProvided,
  NoContentTypeHeader,
  NotAnImageType,
  NotAModOrAdmin,
  NoAdmins,
  NotTopAdmin,
  NotTopMod,
  NotLoggedIn,
  SiteBan,
  Deleted,
  BannedFromCommunity,
  CouldntFindCommunity,
  CouldntFindPerson,
  PersonIsBlocked,
  CommunityIsBlocked,
  InstanceIsBlocked,
  DownvotesAreDisabled,
  InstanceIsPrivate,
  /// Password must be between 10 and 60 characters
  InvalidPassword,
  SiteDescriptionLengthOverflow,
  HoneypotFailed,
  RegistrationApplicationIsPending,
  CantEnablePrivateInstanceAndFederationTogether,
  Locked,
  CouldntCreateComment,
  MaxCommentDepthReached,
  NoCommentEditAllowed,
  OnlyAdminsCanCreateCommunities,
  CommunityAlreadyExists,
  LanguageNotAllowed,
  OnlyModsCanPostInCommunity,
  CouldntUpdatePost,
  NoPostEditAllowed,
  CouldntFindPost,
  EditPrivateMessageNotAllowed,
  SiteAlreadyExists,
  ApplicationQuestionRequired,
  InvalidDefaultPostListingType,
  RegistrationClosed,
  RegistrationApplicationAnswerRequired,
  EmailAlreadyExists,
  FederationForbiddenByStrictAllowList,
  PersonIsBannedFromCommunity,
  ObjectIsNotPublic,
  InvalidCommunity,
  CannotCreatePostOrCommentInDeletedOrRemovedCommunity,
  CannotReceivePage,
  NewPostCannotBeLocked,
  OnlyLocalAdminCanRemoveCommunity,
  OnlyLocalAdminCanRestoreCommunity,
  NoIdGiven,
  IncorrectLogin,
  InvalidQuery,
  ObjectNotLocal,
  PostIsLocked,
  PersonIsBannedFromSite(String),
  InvalidVoteValue,
  PageDoesNotSpecifyCreator,
  PageDoesNotSpecifyGroup,
  NoCommunityFoundInCc,
  NoEmailSetup,
  EmailSmtpServerNeedsAPort,
  MissingAnEmail,
  RateLimitError,
  InvalidName,
  InvalidDisplayName,
  InvalidMatrixId,
  InvalidPostTitle,
  InvalidBodyField,
  BioLengthOverflow,
  MissingTotpToken,
  MissingTotpSecret,
  IncorrectTotpToken,
  CouldntParseTotpSecret,
  CouldntGenerateTotp,
  TotpAlreadyEnabled,
  CouldntLikeComment,
  CouldntSaveComment,
  CouldntCreateReport,
  CouldntResolveReport,
  CommunityModeratorAlreadyExists,
  CommunityUserAlreadyBanned,
  CommunityBlockAlreadyExists,
  CommunityFollowerAlreadyExists,
  CouldntUpdateCommunityHiddenStatus,
  PersonBlockAlreadyExists,
  UserAlreadyExists,
  TokenNotFound,
  CouldntLikePost,
  CouldntSavePost,
  CouldntMarkPostAsRead,
  CouldntUpdateCommunity,
  CouldntUpdateReplies,
  CouldntUpdatePersonMentions,
  PostTitleTooLong,
  CouldntCreatePost,
  CouldntCreatePrivateMessage,
  CouldntUpdatePrivate,
  SystemErrLogin,
  CouldntSetAllRegistrationsAccepted,
  CouldntSetAllEmailVerified,
  Banned,
  CouldntGetComments,
  CouldntGetPosts,
  InvalidUrl,
  EmailSendFailed,
  Slurs,
  CouldntFindObject,
  RegistrationDenied(Option<String>),
  FederationDisabled,
  DomainBlocked(String),
  DomainNotInAllowList(String),
  FederationDisabledByStrictAllowList,
  SiteNameRequired,
  SiteNameLengthOverflow,
  PermissiveRegex,
  InvalidRegex,
  CaptchaIncorrect,
  PasswordResetLimitReached,
  CouldntCreateAudioCaptcha,
  InvalidUrlScheme,
  CouldntSendWebmention,
  ContradictingFilters,
  InstanceBlockAlreadyExists,
  /// Thrown when an API call is submitted with more than 1000 array elements, see [[MAX_API_PARAM_ELEMENTS]]
  TooManyItems,
  CommunityHasNoFollowers,
  BanExpirationInPast,
  InvalidUnixTime,
  InvalidBotAction,
  Unknown(String),
}

impl From<LemmyErrorType> for LemmyError {
  fn from(error_type: LemmyErrorType) -> Self {
    let inner = anyhow::anyhow!("{}", error_type);
    LemmyError {
      error_type,
      inner,
      context: SpanTrace::capture(),
    }
  }
}

pub trait LemmyErrorExt<T, E: Into<anyhow::Error>> {
  fn with_lemmy_type(self, error_type: LemmyErrorType) -> Result<T, LemmyError>;
}

impl<T, E: Into<anyhow::Error>> LemmyErrorExt<T, E> for Result<T, E> {
  fn with_lemmy_type(self, error_type: LemmyErrorType) -> Result<T, LemmyError> {
    self.map_err(|error| LemmyError {
      error_type,
      inner: error.into(),
      context: SpanTrace::capture(),
    })
  }
}
pub trait LemmyErrorExt2<T> {
  fn with_lemmy_type(self, error_type: LemmyErrorType) -> Result<T, LemmyError>;
  fn into_anyhow(self) -> Result<T, anyhow::Error>;
}

impl<T> LemmyErrorExt2<T> for Result<T, LemmyError> {
  fn with_lemmy_type(self, error_type: LemmyErrorType) -> Result<T, LemmyError> {
    self.map_err(|mut e| {
      e.error_type = error_type;
      e
    })
  }
  // this function can't be an impl From or similar because it would conflict with one of the other broad Into<> implementations
  fn into_anyhow(self) -> Result<T, anyhow::Error> {
    self.map_err(|e| e.inner)
  }
}

#[cfg(test)]
mod tests {
  #![allow(clippy::unwrap_used)]
  #![allow(clippy::indexing_slicing)]
  use super::*;
  use actix_web::{body::MessageBody, ResponseError};
  use std::fs::read_to_string;
  use strum::IntoEnumIterator;

  #[test]
  fn deserializes_no_message() {
    let err = LemmyError::from(LemmyErrorType::Banned).error_response();
    let json = String::from_utf8(err.into_body().try_into_bytes().unwrap().to_vec()).unwrap();
    assert_eq!(&json, "{\"error\":\"banned\"}")
  }

  #[test]
  fn deserializes_with_message() {
    let reg_banned = LemmyErrorType::PersonIsBannedFromSite(String::from("reason"));
    let err = LemmyError::from(reg_banned).error_response();
    let json = String::from_utf8(err.into_body().try_into_bytes().unwrap().to_vec()).unwrap();
    assert_eq!(
      &json,
      "{\"error\":\"person_is_banned_from_site\",\"message\":\"reason\"}"
    )
  }

  /// Check if errors match translations. Disabled because many are not translated at all.
  #[test]
  #[ignore]
  fn test_translations_match() {
    #[derive(Deserialize)]
    struct Err {
      error: String,
    }

    let translations = read_to_string("translations/translations/en.json").unwrap();
    LemmyErrorType::iter().for_each(|e| {
      let msg = serde_json::to_string(&e).unwrap();
      let msg: Err = serde_json::from_str(&msg).unwrap();
      let msg = msg.error;
      assert!(translations.contains(&format!("\"{msg}\"")), "{msg}");
    });
  }
}