1 files changed, 65 insertions, 6 deletions

diff --git a/src/launcher.rs b/src/launcher.rs
index 4c4f762..5dfc68a 100644
--- a/src/launcher.rs
+++ b/src/launcher.rs
@@ -2,16 +2,21 @@ mod constants;
 mod version;
 mod profile;
 mod strsub;
+mod download;
+mod request;
 
 use std::borrow::Cow;
 use std::collections::HashMap;
 use std::env::consts::{ARCH, OS};
 use std::error::Error;
 use std::fmt::{Display, Formatter};
+use std::io::ErrorKind;
 use std::path::{Path, PathBuf};
 use serde::{Deserialize, Serialize};
-use sha1_smol::Digest;
+use sha1_smol::Sha1;
 use sysinfo::System;
+use tokio::fs::File;
+use tokio::io::AsyncReadExt;
 use version::VersionList;
 use profile::{Instance, Profile};
 use crate::launcher::version::{VersionResolveError, VersionResult};
@@ -57,14 +62,22 @@ pub enum LaunchError {
 impl Display for LaunchError {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match &self {
-            LaunchError::UnknownVersion(id) => write!(f, "Unknown version ID: {id}"),
+            LaunchError::UnknownVersion(id) => write!(f, "unknown version id: {id}"),
             LaunchError::LoadVersion(e) => write!(f, "error loading remote version: {e}"),
             LaunchError::ResolveVersion(e) => write!(f, "error resolving remote version: {e}")
         }
     }
 }
 
-impl Error for LaunchError {}
+impl Error for LaunchError {
+    fn cause(&self) -> Option<&dyn Error> {
+        match &self {
+            LaunchError::LoadVersion(e) => Some(e.as_ref()),
+            LaunchError::ResolveVersion(e) => Some(e),
+            _ => None
+        }
+    }
+}
 
 impl Launcher {
     // FIXME: more descriptive error type por favor
@@ -133,6 +146,23 @@ impl Launcher {
     }
 }
 
+#[derive(Debug, Clone)]
+enum LibraryError {
+    InvalidName(String),
+    IOError(ErrorKind)
+}
+
+impl Display for LibraryError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            LibraryError::InvalidName(name) => write!(f, "invalid name: {name}"),
+            LibraryError::IOError(e) => write!(f, "io error reading library: {e}"),
+        }
+    }
+}
+
+impl Error for LibraryError {}
+
 impl LibraryRepository {
     fn get_artifact_base_dir(name: &str) -> Option<PathBuf> {
         let end_of_gid = name.find(':')?;
@@ -167,8 +197,37 @@ impl LibraryRepository {
         Some(p)
     }
 
-    async fn should_redownload(&self, lib: &Library, classifier: Option<&str>) -> Result<bool, Box<dyn Error>> {
-        let path = Self::get_artifact_path(lib.name.as_str(), classifier);
+    async fn should_redownload(&self, lib: &Library, classifier: Option<&str>) -> Result<bool, LibraryError> {
+        let path = Self::get_artifact_path(lib.name.as_str(), classifier)
+            .map_or_else(|| Err(LibraryError::InvalidName(lib.name.clone())), |p| Ok(p))?;
+
+        let mut f = match File::open(path).await {
+            Ok(f) => f,
+            Err(e) => return match e.kind() {
+                ErrorKind::NotFound => Ok(true),
+                e => Err(LibraryError::IOError(e))
+            }
+        };
+
+        let mut data = [0u8; 4096];
+        let mut sha1 = Sha1::new();
+
+        loop {
+            let n = match f.read(&mut data).await {
+                Ok(n) => n,
+                Err(e) => return match e.kind() {
+                    ErrorKind::Interrupted => continue,
+                    kind => Err(LibraryError::IOError(kind))
+                }
+            };
+
+            if n == 0 {
+                break; // we reached the end of the file
+            }
+
+            sha1.update(&data[..n]);
+        }
+
 
         todo!()
     }
@@ -185,7 +244,7 @@ impl SystemInfo {
 
         let mut os_version = System::os_version().unwrap_or_default();
         if os == OperatingSystem::Windows && (os_version.starts_with("10") || os_version.starts_with("11")) {
-            os_version.replace_range(..2, "10.0"); // java expects this funny business...
+            os_version.replace_range(..2, "10.0"); // minecraft expects this funny business...
         }
 
         let mut arch = ARCH.to_owned();