use std::{fmt, sync::LazyLock};

use log::{debug, trace};
use regex::Regex;
use serde::{Deserialize, Serialize};

use crate::error;

// pub struct AliasID(String);
// pub struct ShareID(String);

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct FileID(String);

impl fmt::Display for FileID {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str(&self.0)
    }
}

impl AsRef<str> for FileID {
    fn as_ref(&self) -> &str {
        &self.0
    }
}

impl TryFrom<String> for FileID {
    type Error = error::Error;

    fn try_from(value: String) -> error::Result<Self> {
        /// Pattern breakdown:
        /// - `^([^:/?#]+)://`        – scheme (anything but `:/?#`) + `"://"`
        /// - `([^/?#]+)`             – authority/host (anything but `/?#`)
        /// - `/api/v2/alias/upload/` – literal path segment
        /// - `([^/]+)`               – capture SID (one or more non-slash chars)
        /// - `/files/tus/`           – literal path segment
        /// - `(?P<fid>[^/]+)`        – capture FID (one or more non-slash chars)
        /// - `$`                     – end of string
        static UPLOAD_URL_RE: LazyLock<Regex> = LazyLock::new(|| {
            trace!("compiling UPLOAD_URL_RE");

            Regex::new(
                r"^([^:/?#]+)://([^/?#]+)/api/v2/alias/upload/[^/]+/files/tus/(?P<fid>[^/]+)$",
            )
            .expect("Regex compilation failed")
        });

        trace!("TryFrom {value:?}");

        if let Some(fid) = UPLOAD_URL_RE
            .captures(&value)
            .and_then(|caps| caps.name("fid").map(|m| m.as_str()))
        {
            let result = Self(fid.to_owned());
            debug!("{result:?}");

            Ok(result)
        } else {
            Err(error::Error::mismatch(
                "<proto>://<base>/api/v2/alias/upload/<share>/files/tus/<file>",
                value,
            ))
        }
    }
}

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

    #[test]
    fn test_fileid_tryfrom_string() {
        let good = "https://example.com/api/v2/alias/upload/SID123/files/tus/FID456".to_owned();
        let good = FileID::try_from(good);
        assert!(good.is_ok());
        assert_eq!(good.unwrap().as_ref(), "FID456");

        let bad = "https://example.com/api/v2/alias/upload//files/tus/FID456".to_owned(); // missing SID
        assert!(FileID::try_from(bad).is_err());

        let bad = "https://example.com/api/v2/alias/upload/SID123/files/tus/".to_owned(); // missing FID
        assert!(FileID::try_from(bad).is_err());
    }
}