use serde::Serialize;
use thiserror::Error;

#[allow(dead_code)]
#[derive(Debug, Error, Clone)]
pub enum IdxError {
    #[error("symbol not found: {0}")]
    SymbolNotFound(String),
    #[error("provider rate limited")]
    RateLimited,
    #[error("provider unavailable")]
    ProviderUnavailable,
    #[error("unsupported: {0}")]
    Unsupported(String),
    #[error("parse error: {0}")]
    ParseError(String),
    #[error("cache miss: {0}")]
    CacheMiss(String),
    #[error("offline: {0}")]
    Offline(String),
    #[error("config error: {0}")]
    ConfigError(String),
    #[error("io error: {0}")]
    Io(String),
    #[error("http error: {0}")]
    Http(String),
    #[error("auth error: {0}")]
    AuthError(String),
    #[error("database error: {0}")]
    DatabaseError(String),
    #[error("PDF parse error: {0}")]
    PdfParseError(String),
    #[error("invalid input: {0}")]
    InvalidInput(String),
    #[error("no market data: {0}")]
    NoMarketData(String),
}

#[derive(Debug, Clone, Copy, Serialize, PartialEq, Eq)]
pub enum ErrorCode {
    SymbolNotFound,
    RateLimited,
    ProviderUnavailable,
    Unsupported,
    ParseError,
    CacheMiss,
    Offline,
    ConfigError,
    Io,
    Http,
    AuthError,
    DatabaseError,
    PdfParseError,
    InvalidInput,
    NoMarketData,
}

/// The stable wire form frontends emit, e.g. `SYMBOLNOTFOUND`.
impl std::fmt::Display for ErrorCode {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(&format!("{self:?}").to_uppercase())
    }
}

impl IdxError {
    pub fn code(&self) -> ErrorCode {
        match self {
            Self::SymbolNotFound(_) => ErrorCode::SymbolNotFound,
            Self::RateLimited => ErrorCode::RateLimited,
            Self::ProviderUnavailable => ErrorCode::ProviderUnavailable,
            Self::Unsupported(_) => ErrorCode::Unsupported,
            Self::ParseError(_) => ErrorCode::ParseError,
            Self::CacheMiss(_) => ErrorCode::CacheMiss,
            Self::Offline(_) => ErrorCode::Offline,
            Self::ConfigError(_) => ErrorCode::ConfigError,
            Self::Io(_) => ErrorCode::Io,
            Self::Http(_) => ErrorCode::Http,
            Self::AuthError(_) => ErrorCode::AuthError,
            Self::DatabaseError(_) => ErrorCode::DatabaseError,
            Self::PdfParseError(_) => ErrorCode::PdfParseError,
            Self::InvalidInput(_) => ErrorCode::InvalidInput,
            Self::NoMarketData(_) => ErrorCode::NoMarketData,
        }
    }

    /// Exit status by error class, so scripts can branch without parsing
    /// stderr. Clap usage errors also exit 2. See docs/DESIGN.md.
    pub fn exit_code(&self) -> i32 {
        match self.code() {
            ErrorCode::InvalidInput | ErrorCode::ConfigError => 2,
            ErrorCode::SymbolNotFound | ErrorCode::NoMarketData | ErrorCode::CacheMiss => 3,
            ErrorCode::Http
            | ErrorCode::RateLimited
            | ErrorCode::ProviderUnavailable
            | ErrorCode::Offline
            | ErrorCode::AuthError => 4,
            ErrorCode::Unsupported => 5,
            ErrorCode::Io
            | ErrorCode::ParseError
            | ErrorCode::DatabaseError
            | ErrorCode::PdfParseError => 1,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::{ErrorCode, IdxError};

    #[test]
    fn display_and_code_work() {
        let err = IdxError::SymbolNotFound("BBCA".to_string());
        assert_eq!(err.to_string(), "symbol not found: BBCA");
        assert_eq!(err.code(), ErrorCode::SymbolNotFound);

        let parse = IdxError::ParseError("bad json".to_string());
        assert_eq!(parse.code(), ErrorCode::ParseError);

        let unsupported = IdxError::Unsupported("history unavailable".to_string());
        assert_eq!(unsupported.code(), ErrorCode::Unsupported);
    }
}