use std::fmt;
use std::path::PathBuf;

use thiserror::Error;

#[derive(Debug, Error)]
pub enum ConfigError {
    #[error("failed to load .env file: {0}")]
    DotEnv(#[from] dotenvy::Error),

    #[error("config parse/merge error: {0}")]
    Figment(Box<figment::Error>),

    #[error("config I/O error: {0}")]
    Io(#[from] std::io::Error),

    #[error("config validation failed: {0}")]
    Validation(String),
}
impl From<figment::Error> for ConfigError {
    fn from(error: figment::Error) -> Self {
        // Boxed because a figment error carries ~200 bytes of provenance; an
        // inline variant would make every `Result<_, ConfigError>` in the
        // workspace pay for it on the success path too.
        Self::Figment(Box::new(error))
    }
}

#[derive(Debug)]
pub enum ConfigLoadError {
    Section { key: String, path: PathBuf },
    Load { path: PathBuf, message: String },
}

impl fmt::Display for ConfigLoadError {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Section { key, path } => {
                write!(formatter, "{} has no `{key}` section", path.display())
            }
            Self::Load { path, message } => {
                write!(formatter, "failed to load {}: {message}", path.display())
            }
        }
    }
}

impl std::error::Error for ConfigLoadError {}