//! The system clipboard, behind the `"+` register (and behind every yank
//! and paste with `clipboard = "unnamedplus"`). It's opened the first time
//! it's used, and kept open: on Linux, text copied there lasts as long as
//! cumulus runs, or until a clipboard manager takes it over.
//!
//! The tests keep their clipboard in memory, so they never touch yours.

/// The system clipboard.
#[derive(Default)]
pub struct Clipboard {
    #[cfg(not(test))]
    system: Option<arboard::Clipboard>,
    #[cfg(test)]
    text: Option<String>,
}

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

#[cfg(not(test))]
impl Clipboard {
    /// The text on the clipboard.
    pub fn read(&mut self) -> Result<String, String> {
        self.open()?.get_text().map_err(problem)
    }

    /// Puts text on the clipboard.
    pub fn write(&mut self, text: &str) -> Result<(), String> {
        self.open()?.set_text(text.to_string()).map_err(problem)
    }

    fn open(&mut self) -> Result<&mut arboard::Clipboard, String> {
        if self.system.is_none() {
            self.system = Some(arboard::Clipboard::new().map_err(problem)?);
        }
        self.system.as_mut().ok_or_else(|| "the clipboard isn't available".to_string())
    }
}

/// What went wrong with the clipboard, in words.
#[cfg(not(test))]
fn problem(error: arboard::Error) -> String {
    match error {
        arboard::Error::ContentNotAvailable => "the clipboard holds no text".to_string(),
        error => format!("the clipboard isn't available: {error}"),
    }
}

#[cfg(test)]
impl Clipboard {
    pub fn read(&mut self) -> Result<String, String> {
        self.text.clone().ok_or_else(|| "the clipboard holds no text".to_string())
    }

    pub fn write(&mut self, text: &str) -> Result<(), String> {
        self.text = Some(text.to_string());
        Ok(())
    }
}