use std::borrow::Cow;

use crate::{
    snapshot::InstanceSnapshot,
    vfs::{Vfs, VfsEntry, VfsFetcher},
};

use super::{
    context::InstanceSnapshotContext,
    middleware::{SnapshotInstanceResult, SnapshotMiddleware},
    util::match_file_name,
};

pub struct SnapshotRbxmx;

impl SnapshotMiddleware for SnapshotRbxmx {
    fn from_vfs<F: VfsFetcher>(
        _context: &mut InstanceSnapshotContext,
        vfs: &mut Vfs<F>,
        entry: &VfsEntry,
    ) -> SnapshotInstanceResult<'static> {
        if entry.is_directory() {
            return Ok(None);
        }

        let instance_name = match match_file_name(entry.path(), ".rbxmx") {
            Some(name) => name,
            None => return Ok(None),
        };

        let options = rbx_xml::DecodeOptions::new()
            .property_behavior(rbx_xml::DecodePropertyBehavior::ReadUnknown);

        let temp_tree = rbx_xml::from_reader(entry.contents(vfs)?, options)
            .expect("TODO: Handle rbx_xml errors");

        let root_instance = temp_tree.get_instance(temp_tree.get_root_id()).unwrap();
        let children = root_instance.get_children_ids();

        if children.len() == 1 {
            let mut snapshot = InstanceSnapshot::from_tree(&temp_tree, children[0]);
            snapshot.name = Cow::Owned(instance_name.to_owned());
            snapshot.metadata.instigating_source = Some(entry.path().to_path_buf().into());
            snapshot.metadata.relevant_paths = vec![entry.path().to_path_buf()];

            Ok(Some(snapshot))
        } else {
            panic!("Rojo doesn't have support for model files with zero or more than one top-level instances yet.");
        }
    }
}

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

    use std::collections::HashMap;

    use crate::vfs::{NoopFetcher, VfsDebug, VfsSnapshot};

    #[test]
    fn model_from_vfs() {
        let mut vfs = Vfs::new(NoopFetcher);
        let file = VfsSnapshot::file(
            r#"
            <roblox version="4">
                <Item class="Folder" referent="0">
                    <Properties>
                        <string name="Name">THIS NAME IS IGNORED</string>
                    </Properties>
                </Item>
            </roblox>
        "#,
        );

        vfs.debug_load_snapshot("/foo.rbxmx", file);

        let entry = vfs.get("/foo.rbxmx").unwrap();
        let instance_snapshot =
            SnapshotRbxmx::from_vfs(&mut InstanceSnapshotContext::default(), &mut vfs, &entry)
                .unwrap()
                .unwrap();

        assert_eq!(instance_snapshot.name, "foo");
        assert_eq!(instance_snapshot.class_name, "Folder");
        assert_eq!(instance_snapshot.properties, HashMap::new());
        assert_eq!(instance_snapshot.children, Vec::new());
    }
}