use crate::rpcgit::error::BabyError;

#[derive(Debug, thiserror::Error)]
pub enum GitError {
    #[error("cache error: {0}")]
    Cache(#[from] cache::CacheError),
    #[error("invalid argument: {0}")]
    InvalidArgument(String),
    #[error("conflict: {0}")]
    Conflict(String),
    #[error("resource not found")]
    NotFound,
    #[error("unauthorized")]
    Unauthorized,
    #[error("forbidden")]
    Forbidden,
    #[error("git error: {0}")]
    Git(#[from] BabyError),
    #[error("not implemented: {0}")]
    Unimplemented(&'static str),
    #[error("internal error: {0}")]
    Internal(String),
}

impl From<sea_orm::DbErr> for GitError {
    fn from(err: sea_orm::DbErr) -> Self {
        if is_unique_violation(&err) {
            Self::Conflict("resource already exists".to_string())
        } else {
            Self::Internal(format!("database error: {err}"))
        }
    }
}

impl From<sea_orm::TransactionError<sea_orm::DbErr>> for GitError {
    fn from(err: sea_orm::TransactionError<sea_orm::DbErr>) -> Self {
        match &err {
            sea_orm::TransactionError::Transaction(db_err) if is_unique_violation(db_err) => {
                Self::Conflict("resource already exists".to_string())
            }
            _ => Self::Internal(format!("database transaction error: {err}")),
        }
    }
}

impl From<sea_orm::TransactionError<GitError>> for GitError {
    fn from(err: sea_orm::TransactionError<GitError>) -> Self {
        match err {
            sea_orm::TransactionError::Connection(db_err) => Self::from(db_err),
            sea_orm::TransactionError::Transaction(git_err) => git_err,
        }
    }
}

impl From<std::io::Error> for GitError {
    fn from(err: std::io::Error) -> Self {
        Self::Internal(format!("io error: {err}"))
    }
}

impl axum::response::IntoResponse for GitError {
    fn into_response(self) -> axum::response::Response {
        use axum::http::StatusCode;
        let status = match &self {
            Self::NotFound => StatusCode::NOT_FOUND,
            Self::Unauthorized => StatusCode::UNAUTHORIZED,
            Self::Forbidden => StatusCode::FORBIDDEN,
            Self::Conflict(_) => StatusCode::CONFLICT,
            Self::InvalidArgument(_) => StatusCode::BAD_REQUEST,
            Self::Unimplemented(_) => StatusCode::NOT_IMPLEMENTED,
            Self::Cache(_) | Self::Git(_) | Self::Internal(_) => StatusCode::INTERNAL_SERVER_ERROR,
        };
        let body = match &self {
            Self::Cache(_) | Self::Git(_) | Self::Internal(_) => {
                tracing::warn!(error = %self, "git internal error");
                "internal server error".to_string()
            }
            Self::Unimplemented(_) => self.to_string(),
            other => other.to_string(),
        };
        let mut resp = (status, body).into_response();
        if status == StatusCode::UNAUTHORIZED {
            resp.headers_mut().insert(
                axum::http::header::WWW_AUTHENTICATE,
                axum::http::HeaderValue::from_static("Basic realm=\"gitdata\""),
            );
        }
        resp
    }
}

pub fn is_unique_violation(err: &sea_orm::DbErr) -> bool {
    let msg = err.to_string().to_lowercase();
    msg.contains("unique") || msg.contains("duplicate") || msg.contains("23505")
}

pub fn map_baby(err: BabyError) -> GitError {
    use BabyError::*;
    match err {
        BranchNotFound(_)
        | TagNotFound(_)
        | RefNotFound(_)
        | RevisionNotFound(_)
        | BlobNotFound { .. }
        | RemoteNotFound(_)
        | PathNotFound { .. }
        | MergeBaseNotFound(_) => GitError::NotFound,
        BranchAlreadyExists(name) | TagAlreadyExists(name) | RemoteAlreadyExists(name) => {
            GitError::Conflict(format!("`{name}` already exists"))
        }
        RefUpdateRejected(reason) => GitError::Conflict(reason),
        RevisionEmpty
        | RevisionInvalid(_)
        | InvalidRefName(_)
        | InvalidBranchName(_)
        | InvalidTagName(_)
        | InvalidRemoteUrl(_)
        | InvalidGitArg(_)
        | InvalidRange
        | PathEscapesRepository
        | InvalidTimestamp(_)
        | AmbiguousRef { .. }
        | PayloadTooLarge { .. } => GitError::InvalidArgument(err.to_string()),
        other => GitError::Git(other),
    }
}