use figment::Provider;
use ignore::{Walk, WalkBuilder};
use std::{path::PathBuf, vec::IntoIter};
use tracing::warn;

pub use config::{Config, PathEntry};
pub use error::{Error, Result};

mod config;
mod error;

pub struct Paths {
    paths_iter: IntoIter<PathEntry>,
    iter: Option<Walk>,
}

impl Paths {
    pub fn new() -> Result<Self> {
        Self::from_provider(Config::figment())
    }

    /// Extract `Config` from `provider` to construct new `Paths`
    pub fn from_provider<T: Provider>(provider: T) -> Result<Self> {
        Config::extract(&provider)
            .map_err(Into::into)
            .map(Into::into)
    }
}

impl From<Vec<PathEntry>> for Paths {
    fn from(value: Vec<PathEntry>) -> Self {
        Self {
            paths_iter: value.into_iter(),
            iter: None,
        }
    }
}

impl From<Config> for Paths {
    fn from(value: Config) -> Self {
        value.paths.into()
    }
}

impl Iterator for Paths {
    type Item = PathBuf;

    #[tracing::instrument(skip(self))]
    fn next(&mut self) -> Option<Self::Item> {
        loop {
            match self.iter.as_mut().and_then(|iter| iter.next()) {
                Some(Ok(d)) => return Some(d.into_path()),
                Some(Err(err)) => warn!("{:?}", err),
                None => {
                    let next = self.paths_iter.next()?;
                    self.iter = Some(
                        WalkBuilder::new(next.path)
                            .standard_filters(true)
                            .max_depth(next.recurse)
                            .hidden(next.hidden)
                            .build(),
                    );
                }
            };
        }
    }
}

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

    #[test]
    fn test_iteration() {
        let temp_dir = tempfile::Builder::new()
            .tempdir()
            .unwrap()
            .path()
            .to_owned();

        let project_dir = temp_dir.join("project_dir");
        let project1 = temp_dir.join("project_dir/project1");
        let project2 = temp_dir.join("project_dir/project2");
        let project3 = temp_dir.join("project3");
        let project4 = temp_dir.join("subdir/project4");

        let paths = Paths::from(Vec::from([
            PathEntry {
                path: project_dir.to_owned(),
                hidden: false,
                recurse: Some(1),
            },
            PathEntry {
                path: project3.to_owned(),
                hidden: false,
                recurse: Some(0),
            },
            PathEntry {
                path: project4.to_owned(),
                hidden: false,
                recurse: Some(0),
            },
        ]));

        let mut path_bufs = Vec::from([project_dir, project1, project2, project3, project4]);
        path_bufs.iter().try_for_each(fs::create_dir_all).unwrap();
        path_bufs.sort();

        let mut results = paths.into_iter().collect::<Vec<PathBuf>>();
        results.sort();

        assert_eq!(path_bufs, results);
    }
}