Fetch file version from Nexus

When importing an archive file downloaded from Nexus, the file name does
include a version field. But, presumably for compatibility reasons,
Nexus replaces special characters with `-`, so that this field doesn't
match common schemes like `1.0.0`.
So instead we use the also included update timestamp to find the
corresponding file info from Nexus and use the version data from that.

Closes #131.

crates/dtmm/src/controller/import.rs

@@ -381,7 +381,7 @@ pub(crate) async fn import_mod(state: ActionState, info: FileInfo) -> Result<Mod
         .wrap_err_with(|| format!("Failed to read file {}", info.path.display()))?;
     let data = Cursor::new(data);
 
-    let nexus = if let Some((_, id, version, _)) = info
+    let nexus = if let Some((_, id, version, timestamp)) = info
         .path
         .file_name()
         .and_then(|s| s.to_str())
@@ -393,9 +393,23 @@ pub(crate) async fn import_mod(state: ActionState, info: FileInfo) -> Result<Mod
                 .mods_id(id)
                 .await
                 .wrap_err_with(|| format!("Failed to query mod {} from Nexus", id))?;
-            let info = NexusInfo::from(mod_info);
 
-            tracing::debug!("{:?}", info);
+            let version = match api.file_version(id, timestamp).await {
+                Ok(version) => version,
+                Err(err) => {
+                    let err = Report::new(err);
+                    tracing::warn!(
+                        "Failed to fetch version for Nexus download. \
+                        Falling back to file name:\n{:?}",
+                        err
+                    );
+                    version
+                }
+            };
+
+            let info = NexusInfo::from(mod_info);
+            tracing::debug!(version, ?info);
+
             Some((info, version))
         } else {
             None

lib/nexusmods/src/lib.rs

@@ -39,6 +39,8 @@ pub enum Error {
     Infallible(#[from] Infallible),
     #[error("invalid NXM URL '{}': {0}", .1.as_str())]
     InvalidNXM(&'static str, Url),
+    #[error("{0}")]
+    Custom(String),
 }
 
 pub type Result<T> = std::result::Result<T, Error>;
@@ -102,6 +104,28 @@ impl Api {
         self.send(req).await
     }
 
+    #[tracing::instrument(skip(self))]
+    pub async fn file_version<T>(&self, id: u64, timestamp: T) -> Result<String>
+    where
+        T: std::fmt::Debug,
+        OffsetDateTime: PartialEq<T>,
+    {
+        let url = BASE_URL_GAME.join(&format!("mods/{id}/files.json"))?;
+        let req = self.client.get(url);
+        let files: FileList = self.send(req).await?;
+
+        let Some(file) = files
+            .files
+            .into_iter()
+            .find(|file| file.updated_timestamp == timestamp)
+        else {
+            let err = Error::Custom("Timestamp does not match any file".into());
+            return Err(err);
+        };
+
+        Ok(file.version)
+    }
+
     pub fn parse_file_name<S: AsRef<str>>(
         name: S,
     ) -> Option<(String, u64, String, OffsetDateTime)> {

lib/nexusmods/src/types.rs

@@ -64,6 +64,35 @@ pub struct Mod {
     // pub contains_adult_content: bool,
 }
 
+#[derive(Debug, Deserialize)]
+pub struct File {
+    pub id: Vec<u64>,
+    pub uid: u64,
+    pub file_id: u64,
+    pub name: String,
+    pub version: String,
+    pub category_id: u64,
+    pub category_name: String,
+    pub is_primary: bool,
+    pub size: u64,
+    pub file_name: String,
+    #[serde(with = "time::serde::timestamp")]
+    pub updated_timestamp: OffsetDateTime,
+    pub mod_version: String,
+    pub external_virus_scan_url: String,
+    pub description: String,
+    pub size_kb: u64,
+    pub size_in_bytes: u64,
+    pub changelog_html: String,
+    pub content_preview_link: String,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct FileList {
+    pub files: Vec<File>,
+    // pub file_updates: Vec<serde_json::Value>,
+}
+
 #[derive(Debug, Deserialize)]
 pub struct DownloadLink {
     pub name: String,