use std::sync::Arc;

use actix_web::{http::StatusCode, HttpResponse, ResponseError};
use color_eyre::Report;

use crate::error_code::ErrorCode;

pub(crate) struct Error {
    inner: color_eyre::Report,
    debug: Arc<str>,
    display: Arc<str>,
}

impl Error {
    fn kind(&self) -> Option<&UploadError> {
        self.inner.downcast_ref()
    }

    pub(crate) fn root_cause(&self) -> &(dyn std::error::Error + 'static) {
        self.inner.root_cause()
    }

    pub(crate) fn error_code(&self) -> ErrorCode {
        self.kind()
            .map(|e| e.error_code())
            .unwrap_or(ErrorCode::UNKNOWN_ERROR)
    }

    pub(crate) fn is_disconnected(&self) -> bool {
        self.kind().map(|e| e.is_disconnected()).unwrap_or(false)
    }
}

impl std::fmt::Debug for Error {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(&self.debug)
    }
}

impl std::fmt::Display for Error {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(&self.display)
    }
}

impl std::error::Error for Error {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        self.inner.source()
    }
}

impl<T> From<T> for Error
where
    UploadError: From<T>,
{
    fn from(error: T) -> Self {
        let inner = Report::from(UploadError::from(error));
        let debug = Arc::from(format!("{inner:?}"));
        let display = Arc::from(format!("{inner}"));

        Error {
            inner,
            debug,
            display,
        }
    }
}

#[derive(Debug, thiserror::Error)]
pub(crate) enum UploadError {
    #[error("Couldn't upload file")]
    Upload(#[from] actix_form_data::Error),

    #[error("Error in DB")]
    Repo(#[from] crate::repo::RepoError),

    #[error("Error in old repo")]
    OldRepo(#[from] crate::repo_04::RepoError),

    #[error("Error interacting with filesystem")]
    Io(#[from] std::io::Error),

    #[error("Error validating upload")]
    Validation(#[from] crate::validate::ValidationError),

    #[error("Error in store")]
    Store(#[source] crate::store::StoreError),

    #[error("Error in ffmpeg")]
    Ffmpeg(#[from] crate::ffmpeg::FfMpegError),

    #[error("Error in imagemagick")]
    Magick(#[from] crate::magick::MagickError),

    #[error("Error in exiftool")]
    Exiftool(#[from] crate::exiftool::ExifError),

    #[error("Error building reqwest client")]
    BuildClient(#[source] reqwest::Error),

    #[error("Error making request")]
    RequestMiddleware(#[from] reqwest_middleware::Error),

    #[error("Error in request response")]
    Request(#[from] reqwest::Error),

    #[error("pict-rs is in read-only mode")]
    ReadOnly,

    #[error("Requested file extension cannot be served by source file")]
    InvalidProcessExtension,

    #[error("Provided process path is invalid")]
    ParsePath,

    #[error("Failed to acquire the semaphore")]
    Semaphore,

    #[error("Panic in blocking operation")]
    Canceled,

    #[error("No files present in upload")]
    NoFiles,

    #[error("Requested a file that doesn't exist")]
    MissingAlias,

    #[error("Requested a file that pict-rs lost track of")]
    MissingIdentifier,

    #[error("Provided token did not match expected token")]
    InvalidToken,

    #[error("Process endpoint was called with invalid extension")]
    UnsupportedProcessExtension,

    #[error("Unable to download image, bad response {0}")]
    Download(actix_web::http::StatusCode),

    #[error("Tried to save an image with an already-taken name")]
    DuplicateAlias,

    #[error("Failed to serialize job")]
    PushJob(#[source] serde_json::Error),

    #[error("Range header not satisfiable")]
    Range,

    #[error("Hit limit")]
    Limit(#[from] crate::stream::LimitError),

    #[error("Response timeout")]
    Timeout(#[from] crate::stream::TimeoutError),

    #[error("Failed external validation")]
    FailedExternalValidation,
}

impl UploadError {
    const fn error_code(&self) -> ErrorCode {
        match self {
            Self::Upload(_) => ErrorCode::FILE_UPLOAD_ERROR,
            Self::Repo(e) => e.error_code(),
            Self::OldRepo(_) => ErrorCode::OLD_REPO_ERROR,
            Self::Io(_) => ErrorCode::IO_ERROR,
            Self::Validation(e) => e.error_code(),
            Self::Store(e) => e.error_code(),
            Self::Ffmpeg(e) => e.error_code(),
            Self::Magick(e) => e.error_code(),
            Self::Exiftool(e) => e.error_code(),
            Self::BuildClient(_) | Self::RequestMiddleware(_) | Self::Request(_) => {
                ErrorCode::HTTP_CLIENT_ERROR
            }
            Self::Download(_) => ErrorCode::DOWNLOAD_FILE_ERROR,
            Self::ReadOnly => ErrorCode::READ_ONLY,
            Self::InvalidProcessExtension => ErrorCode::INVALID_FILE_EXTENSION,
            Self::ParsePath => ErrorCode::INVALID_PROCESS_PATH,
            Self::Semaphore => ErrorCode::PROCESS_SEMAPHORE_CLOSED,
            Self::Canceled => ErrorCode::PANIC,
            Self::NoFiles => ErrorCode::VALIDATE_NO_FILES,
            Self::MissingAlias => ErrorCode::ALIAS_NOT_FOUND,
            Self::MissingIdentifier => ErrorCode::LOST_FILE,
            Self::InvalidToken => ErrorCode::INVALID_DELETE_TOKEN,
            Self::UnsupportedProcessExtension => ErrorCode::INVALID_FILE_EXTENSION,
            Self::DuplicateAlias => ErrorCode::DUPLICATE_ALIAS,
            Self::PushJob(_) => ErrorCode::PUSH_JOB,
            Self::Range => ErrorCode::RANGE_NOT_SATISFIABLE,
            Self::Limit(_) => ErrorCode::VALIDATE_FILE_SIZE,
            Self::Timeout(_) => ErrorCode::STREAM_TOO_SLOW,
            Self::FailedExternalValidation => ErrorCode::FAILED_EXTERNAL_VALIDATION,
        }
    }

    const fn is_disconnected(&self) -> bool {
        match self {
            Self::Repo(e) => e.is_disconnected(),
            Self::Store(s) => s.is_disconnected(),
            _ => false,
        }
    }
}

impl From<actix_web::error::BlockingError> for UploadError {
    fn from(_: actix_web::error::BlockingError) -> Self {
        UploadError::Canceled
    }
}

impl From<tokio::sync::AcquireError> for UploadError {
    fn from(_: tokio::sync::AcquireError) -> Self {
        UploadError::Semaphore
    }
}

impl From<crate::store::StoreError> for UploadError {
    fn from(value: crate::store::StoreError) -> Self {
        match value {
            crate::store::StoreError::Repo(repo_error) => Self::Repo(repo_error),
            e => Self::Store(e),
        }
    }
}

impl ResponseError for Error {
    fn status_code(&self) -> StatusCode {
        match self.kind() {
            Some(
                UploadError::DuplicateAlias
                | UploadError::Limit(_)
                | UploadError::NoFiles
                | UploadError::Upload(_)
                | UploadError::Store(crate::store::StoreError::Repo(
                    crate::repo::RepoError::AlreadyClaimed,
                ))
                | UploadError::Repo(crate::repo::RepoError::AlreadyClaimed)
                | UploadError::Validation(_)
                | UploadError::UnsupportedProcessExtension
                | UploadError::InvalidProcessExtension
                | UploadError::ReadOnly
                | UploadError::FailedExternalValidation,
            ) => StatusCode::BAD_REQUEST,
            Some(UploadError::Magick(e)) if e.is_client_error() => StatusCode::BAD_REQUEST,
            Some(UploadError::Ffmpeg(e)) if e.is_client_error() => StatusCode::BAD_REQUEST,
            Some(UploadError::Exiftool(e)) if e.is_client_error() => StatusCode::BAD_REQUEST,
            Some(UploadError::MissingAlias) => StatusCode::NOT_FOUND,
            Some(UploadError::Ffmpeg(e)) if e.is_not_found() => StatusCode::NOT_FOUND,
            Some(UploadError::InvalidToken) => StatusCode::FORBIDDEN,
            Some(UploadError::Range) => StatusCode::RANGE_NOT_SATISFIABLE,
            _ => StatusCode::INTERNAL_SERVER_ERROR,
        }
    }

    fn error_response(&self) -> HttpResponse {
        HttpResponse::build(self.status_code())
            .content_type("application/json")
            .body(
                serde_json::to_string(&serde_json::json!({
                    "msg": self.root_cause().to_string(),
                    "code": self.error_code()
                }))
                .unwrap_or_else(|_| {
                    r#"{"msg":"Request failed","code":"unknown-error"}"#.to_string()
                }),
            )
    }
}