use color_eyre::eyre::{eyre, Result};
use magnet_url::Magnet;

/// Extract magnet links from text
pub fn extract_magnet_links(text: &str) -> Result<Vec<Magnet>> {
    let mut links = Vec::new();

    let mut start_idx = 0;
    while let Some(idx) = text[start_idx..].find("magnet:") {
        let start = start_idx + idx;

        let end = text[start..]
            .find(char::is_whitespace)
            .map(|e| start + e)
            .unwrap_or(text.len());

        let link = &text[start..end];
        let magnet = Magnet::new(link)
            .map_err(|e| eyre!("Failed to parse magnet link '{}': {:?}", link, e))?;
        links.push(magnet);
        start_idx = end;
    }

    Ok(links)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_empty_text() {
        let text = "";

        let links = extract_magnet_links(text);

        assert!(links.unwrap().is_empty());
    }

    #[test]
    fn test_no_magnet_links() {
        let text = "This is a text without any magnet links";

        let links = extract_magnet_links(text);

        assert!(links.unwrap().is_empty());
    }

    #[test]
    fn test_single_magnet_link() {
        let text = "Here is a magnet link: magnet:?xt=urn:btih:example";

        let links = extract_magnet_links(text).unwrap();

        assert_eq!(links.len(), 1);
        assert_eq!(
            links[0],
            Magnet::new_no_validation("magnet:?xt=urn:btih:example")
        );
    }

    #[test]
    fn test_multiple_magnet_links() {
        let text = "First link: magnet:?xt=urn:btih:example1 and second link: magnet:?xt=urn:btih:example2";

        let links = extract_magnet_links(text).unwrap();

        assert_eq!(links.len(), 2);
        assert_eq!(
            links[0],
            Magnet::new_no_validation("magnet:?xt=urn:btih:example1")
        );
        assert_eq!(
            links[1],
            Magnet::new_no_validation("magnet:?xt=urn:btih:example2")
        );
    }

    #[test]
    fn test_magnet_link_at_beginning() {
        let text = "magnet:?xt=urn:btih:example at the beginning";

        let links = extract_magnet_links(text).unwrap();

        assert_eq!(links.len(), 1);
        assert_eq!(
            links[0],
            Magnet::new_no_validation("magnet:?xt=urn:btih:example")
        );
    }

    #[test]
    fn test_magnet_link_at_end() {
        let text = "Link at the end: magnet:?xt=urn:btih:example";

        let links = extract_magnet_links(text).unwrap();

        assert_eq!(links.len(), 1);
        assert_eq!(
            links[0],
            Magnet::new_no_validation("magnet:?xt=urn:btih:example")
        );
    }

    #[test]
    fn test_magnet_link_without_whitespace() {
        let text = "Text containing a link:magnet:?xt=urn:btih:example";

        let links = extract_magnet_links(text).unwrap();

        assert_eq!(links.len(), 1);
        assert_eq!(
            links[0],
            Magnet::new_no_validation("magnet:?xt=urn:btih:example")
        );
    }

    #[test]
    fn test_complex_magnet_link() {
        let text = "Complex link: magnet:?xt=urn:btih:a1b2c3d4e5f6g7h8i9j0&dn=example+file&tr=udp%3A%2F%2Ftracker.example.com%3A80";

        let links = extract_magnet_links(text).unwrap();

        assert_eq!(links.len(), 1);
        assert_eq!(links[0], Magnet::new_no_validation("magnet:?xt=urn:btih:a1b2c3d4e5f6g7h8i9j0&dn=example+file&tr=udp%3A%2F%2Ftracker.example.com%3A80"));
    }
}