1 files changed, 83 insertions, 0 deletions
diff --git a/src-tauri/src/core/modpack/formats/multimc.rs b/src-tauri/src/core/modpack/formats/multimc.rs
new file mode 100644
index 0000000..25449ae
--- /dev/null
+++ b/src-tauri/src/core/modpack/formats/multimc.rs
@@ -0,0 +1,83 @@
+use super::super::{
+    archive::{Archive, read_entry, read_json},
+    types::{ModpackInfo, ParsedModpack},
+};
+
+pub(crate) fn parse(archive: &mut Archive) -> Result<ParsedModpack, String> {
+    let root = find_root(archive).ok_or("not multimc")?;
+    let cfg = read_entry(archive, &format!("{root}instance.cfg")).ok_or("not multimc")?;
+    let name = cfg_value(&cfg, "name").unwrap_or_else(|| "MultiMC Modpack".into());
+
+    let (minecraft_version, mod_loader, mod_loader_version) =
+        read_json(archive, &format!("{root}mmc-pack.json"))
+            .map(|json| parse_components(&json))
+            .unwrap_or_default();
+    let minecraft_version = minecraft_version.or_else(|| cfg_value(&cfg, "IntendedVersion"));
+
+    Ok(ParsedModpack {
+        info: ModpackInfo {
+            name,
+            minecraft_version,
+            mod_loader,
+            mod_loader_version,
+            modpack_type: "multimc".into(),
+            instance_id: None,
+        },
+        files: Vec::new(),
+        override_prefixes: vec![format!("{root}.minecraft/"), format!("{root}minecraft/")],
+    })
+}
+
+fn cfg_value(content: &str, key: &str) -> Option<String> {
+    let prefix = format!("{key}=");
+    content
+        .lines()
+        .find_map(|line| Some(line.strip_prefix(&prefix)?.trim().to_string()))
+}
+
+fn find_root(archive: &mut Archive) -> Option<String> {
+    for index in 0..archive.len() {
+        let name = archive.by_index_raw(index).ok()?.name().to_string();
+        if name == "instance.cfg" {
+            return Some(String::new());
+        }
+        if name.ends_with("/instance.cfg") && name.matches('/').count() == 1 {
+            return Some(name.strip_suffix("instance.cfg")?.to_string());
+        }
+    }
+    None
+}
+
+fn parse_components(json: &serde_json::Value) -> (Option<String>, Option<String>, Option<String>) {
+    let (mut minecraft_version, mut mod_loader, mut mod_loader_version) = (None, None, None);
+
+    for component in json["components"].as_array().into_iter().flatten() {
+        let version = component["version"].as_str().map(String::from);
+        match component["uid"].as_str().unwrap_or("") {
+            "net.minecraft" => minecraft_version = version,
+            "net.minecraftforge" => {
+                mod_loader = Some("forge".into());
+                mod_loader_version = version;
+            }
+            "net.neoforged" => {
+                mod_loader = Some("neoforge".into());
+                mod_loader_version = version;
+            }
+            "net.fabricmc.fabric-loader" => {
+                mod_loader = Some("fabric".into());
+                mod_loader_version = version;
+            }
+            "org.quiltmc.quilt-loader" => {
+                mod_loader = Some("quilt".into());
+                mod_loader_version = version;
+            }
+            "com.mumfrey.liteloader" => {
+                mod_loader = Some("liteloader".into());
+                mod_loader_version = version;
+            }
+            _ => {}
+        }
+    }
+
+    (minecraft_version, mod_loader, mod_loader_version)
+}