use crate::pack;
use quick_error::quick_error;
use std::{
    convert::TryFrom,
    path::{Path, PathBuf},
};

pub mod locate;
pub mod write;

quick_error! {
    #[derive(Debug)]
    pub enum Error {
        InvalidPath(path: PathBuf) {
            display("An 'idx' extension is expected of an index file: '{}'", path.display())
        }
        Pack(err: pack::data::parse::Error) {
            display("Could not instantiate pack")
            from()
            source(err)
        }
        Index(err: pack::index::init::Error) {
            display("Could not instantiate pack index")
            from()
            source(err)
        }
    }
}

/// A packfile with an index
pub struct Bundle {
    pub pack: pack::data::File,
    pub index: pack::index::File,
}

impl Bundle {
    /// `path` is either a pack file or an index file
    pub fn at(path: impl AsRef<Path>) -> Result<Self, Error> {
        Self::try_from(path.as_ref())
    }
}

impl TryFrom<&Path> for Bundle {
    type Error = Error;

    fn try_from(path: &Path) -> Result<Self, Self::Error> {
        let ext = path
            .extension()
            .and_then(|e| e.to_str())
            .ok_or_else(|| Error::InvalidPath(path.to_owned()))?;
        Ok(match ext {
            "idx" => Self {
                index: pack::index::File::at(path)?,
                pack: pack::data::File::at(path.with_extension("pack"))?,
            },
            "pack" => Self {
                pack: pack::data::File::at(path)?,
                index: pack::index::File::at(path.with_extension("idx"))?,
            },
            _ => return Err(Error::InvalidPath(path.to_owned())),
        })
    }
}