rs-rich-ext 0.0.4

//! Optional CLI conveniences, kept outside the faithful command parser.

use crate::encoding::Encoding;

/// Options owned by the extension layer; the executable supplies input/mode facts.
#[derive(Default)]
pub struct CliExtensions {
    pub encoding: Option<Encoding>,
    gif_blocks: Option<bool>,
}

pub const HELP: &str = "        --gif-mode M With --gif: ascii (default) or blocks (half-block pixels).\n                     Blocks fall back to ASCII without color or when piped.\n        --encoding E Explicit text encoding: utf-8, utf-16 (BOM required),\n                     utf-16le or utf-16be. Strict; files, stdin and URLs only.";

impl CliExtensions {
    /// Consume an extension option. Unknown options remain with the mirror parser.
    pub fn parse_option<'a>(
        &mut self,
        arg: &str,
        rest: &mut impl Iterator<Item = &'a String>,
    ) -> Result<bool, String> {
        match arg {
            "--gif-mode" => {
                self.gif_blocks = Some(match rest.next().map(String::as_str) {
                    Some("ascii") => false,
                    Some("blocks") => true,
                    _ => return Err("--gif-mode requires ascii or blocks".into()),
                })
            }
            "--encoding" => {
                self.encoding = Some(
                    rest.next()
                        .ok_or("--encoding requires an encoding name")?
                        .parse()?,
                )
            }
            _ => return Ok(false),
        }
        Ok(true)
    }

    pub fn validate(&self, gif: bool, reads_text: bool) -> Result<(), String> {
        if self.gif_blocks.is_some() && !gif {
            return Err("--gif-mode only has an effect with --gif".into());
        }
        if self.encoding.is_some() && !reads_text {
            return Err("--encoding requires file, stdin or URL text input".into());
        }
        Ok(())
    }

    /// GIFs retain ASCII defaults unless the extension explicitly requests blocks.
    pub fn gif_blocks(&self) -> bool {
        self.gif_blocks.unwrap_or(false)
    }
}