use std::io::Read;
use clap::{Args,Parser,Subcommand};
use anyhow::Result as AResult;
use futures::StreamExt;
use rbx_dom_weak::types::Ref;

type AssetID=u64;
type AssetIDFileMap=Vec<(AssetID,std::path::PathBuf)>;
const CONCURRENT_DECODE:usize=8;
const CONCURRENT_REQUESTS:usize=32;

#[derive(Parser)]
#[command(author,version,about,long_about=None)]
#[command(propagate_version = true)]
struct Cli{
	//asset options
	#[arg(short,long)]
	group:Option<u64>,
	#[arg(long)]
	asset_id:Option<AssetID>,
	//idk how to do this better
	#[arg(long)]
	cookie_literal:Option<String>,
	#[arg(long)]
	cookie_env:Option<String>,
	#[arg(long)]
	cookie_file:Option<std::path::PathBuf>,
	//TODO: read the versions.json file instead of doing this
	//TODO: write file dates instead of versions.json
	#[arg(long)]
	start_version:Option<u64>,
	#[arg(long)]
	end_version:Option<u64>,
	#[arg(long)]
	r#continue:bool,

	//decompile options
	#[arg(long)]
	no_models:Option<bool>,
	#[arg(long)]
	no_scripts:Option<bool>,
	#[arg(long)]
	no_template:Option<bool>,
	#[arg(long)]
	style:Option<String>,

	//git options
	#[arg(long)]
	git_committer_name:Option<String>,
	#[arg(long)]
	git_committer_email:Option<String>,

	#[arg(short,long)]
	input:Option<std::path::PathBuf>,

	#[arg(short,long)]
	output:Option<std::path::PathBuf>,

	#[command(subcommand)]
	command:Commands,
}

#[derive(Subcommand)]
enum Commands{
	DownloadHistory,
	Download,
	Upload,
	Compile,
	Decompile,
	DecompileHistoryIntoGit,
	DownloadAndDecompileHistoryIntoGit,
}

#[derive(Clone,Copy)]
enum DecompileStyle{
	Rox,
	Rojo,
	RoxRojo,
}

#[derive(Args)]
struct PathBufList{
	paths:Vec<std::path::PathBuf>
}

#[derive(serde::Deserialize)]
#[allow(nonstandard_style,dead_code)]
struct VersionPage{
	previousPageCursor:Option<String>,
	nextPageCursor:Option<String>,
	data:Vec<AssetVersion>,
}
#[derive(serde::Deserialize,serde::Serialize)]
#[allow(nonstandard_style,dead_code)]
struct AssetVersion{
	Id:u64,
	assetId:AssetID,
	assetVersionNumber:u64,
	creatorType:String,
	creatorTargetId:u64,
	creatingUniverseId:Option<u64>,
	created:chrono::DateTime<chrono::Utc>,
	isPublished:bool,
}

#[tokio::main]
async fn main()->AResult<()>{
	let cli=Cli::parse();

	let cookie_enum={
		match (cli.cookie_literal,cli.cookie_env,cli.cookie_file){
			(Some(literal),None,None)=>Some(Cookie::Literal(literal)),
			(None,Some(env_var),None)=>Some(Cookie::Environment(env_var)),
			(None,None,Some(path))=>Some(Cookie::File(path)),
			(None,None,None)=>None,
			_=>return Err(anyhow::Error::msg("Cookie was specified multiple times.")),
		}
	};
	let cookie=match cookie_enum{
		Some(c)=>Some(format!(".ROBLOSECURITY={}",match c{
			Cookie::Literal(s)=>s,
			Cookie::Environment(var)=>std::env::var(var)?,
			Cookie::File(path)=>tokio::fs::read_to_string(path).await?,
		})),
		None=>None,
	};

	let decompile_style=match cli.style.as_deref(){
		Some("rox")
		|Some("Rox")=>Some(DecompileStyle::Rox),
		Some("rojo")
		|Some("Rojo")=>Some(DecompileStyle::Rojo),
		Some("rox-rojo")
		|Some("rojo-rox")
		|Some("roxrojo")
		|Some("rojorox")
		|Some("RoxRojo")
		|Some("RojoRox")=>Some(DecompileStyle::RoxRojo),
		None=>None,
		_=>return Err(anyhow::Error::msg("Invalid style")),
	};

	match cli.command{
		Commands::DownloadHistory=>download_history(DownloadHistoryConfig{
			continue_from_versions:cli.r#continue,
			end_version:cli.end_version,
			start_version:cli.start_version.unwrap_or(0),
			output_folder:cli.output.unwrap(),
			cookie:cookie.unwrap(),
			asset_id:cli.asset_id.unwrap(),
		}).await,
		Commands::Download=>download_list(cookie.unwrap(),vec![(cli.asset_id.unwrap(),cli.output.unwrap())]).await,
		Commands::Upload=>upload_list(cookie.unwrap(),cli.group,vec![(cli.asset_id.unwrap(),cli.output.unwrap())]).await,
		Commands::Compile=>compile(cli.input.unwrap(),cli.output.unwrap()),
		Commands::Decompile=>decompile(DecompileConfig{
			style:decompile_style.unwrap(),
			input_file:cli.input.unwrap(),
			output_folder:cli.output.unwrap(),
			write_template:!cli.no_template.unwrap_or(false),
			write_models:!cli.no_models.unwrap_or(false),
			write_scripts:!cli.no_scripts.unwrap_or(false),
		}).await,
		Commands::DecompileHistoryIntoGit=>decompile_history_into_git(DecompileHistoryConfig{
			git_committer_name:cli.git_committer_name.unwrap(),
			git_committer_email:cli.git_committer_email.unwrap(),
			input_folder:cli.input.unwrap(),
			output_folder:cli.output.unwrap(),
			style:decompile_style.unwrap(),
			write_template:!cli.no_template.unwrap_or(false),
			write_models:!cli.no_models.unwrap_or(false),
			write_scripts:!cli.no_scripts.unwrap_or(false),
		 }).await,
		Commands::DownloadAndDecompileHistoryIntoGit=>download_and_decompile_history_into_git(DownloadAndDecompileHistoryConfig{
			git_committer_name:cli.git_committer_name.unwrap(),
			git_committer_email:cli.git_committer_email.unwrap(),
			cookie:cookie.unwrap(),
			asset_id:cli.asset_id.unwrap(),
			output_folder:cli.output.unwrap(),
			style:decompile_style.unwrap(),
			write_template:!cli.no_template.unwrap_or(false),
			write_models:!cli.no_models.unwrap_or(false),
			write_scripts:!cli.no_scripts.unwrap_or(false),
		 }).await,
	}
}

enum Cookie{
	Literal(String),
	Environment(String),
	File(std::path::PathBuf),
}

enum ReaderType<R:Read>{
	GZip(flate2::read::GzDecoder<std::io::BufReader<R>>),
	Raw(std::io::BufReader<R>),
}

fn maybe_gzip_decode<R:Read>(input:R)->AResult<ReaderType<R>>{
	let mut buf=std::io::BufReader::new(input);
	let peek=std::io::BufRead::fill_buf(&mut buf)?;
	match &peek[0..2]{
		b"\x1f\x8b"=>Ok(ReaderType::GZip(flate2::read::GzDecoder::new(buf))),
		_=>Ok(ReaderType::Raw(buf)),
	}
}

async fn upload_list(cookie:String,group:Option<u64>,asset_id_file_map:AssetIDFileMap)->AResult<()>{
	let client=reqwest::Client::new();
	futures::stream::iter(asset_id_file_map.into_iter()
	.map(|(asset_id,file)|{
		let client=&client;
		let cookie=cookie.as_str();
		let group=&group;
		async move{
			let mut url=reqwest::Url::parse("https://data.roblox.com/Data/Upload.ashx?json=1&type=Model&genreTypeId=1")?;
			//url borrow scope
			{
				let mut query=url.query_pairs_mut();//borrow here
				query.append_pair("assetid",asset_id.to_string().as_str());
				match group{
					Some(group_id)=>{query.append_pair("groupId",group_id.to_string().as_str());},
					None=>(),
				}
			}
			
			let body=tokio::fs::read_to_string(file).await?;
			let mut resp=client.post(url.clone())
			.header("Cookie",cookie)
			.body(body.clone())
			.send().await?;

			//This is called a CSRF challenge apparently
			if resp.status()==reqwest::StatusCode::FORBIDDEN{
				if let Some(csrf_token)=resp.headers().get("X-CSRF-Token"){
					resp=client.post(url)
					.header("X-CSRF-Token",csrf_token)
					.header("Cookie",cookie)
					.body(body)
					.send().await?;
				}else{
					return Err(anyhow::Error::msg("Roblox returned 403 with no CSRF"));
				}
			}

			Ok((asset_id,resp.bytes().await?))
		}
	}))
	.buffer_unordered(CONCURRENT_REQUESTS)
	.for_each(|b:AResult<_>|async{
			match b{
				Ok((asset_id,body))=>{
					println!("asset_id={} response.body={:?}",asset_id,body);
				},
				Err(e)=>eprintln!("ul error: {}",e),
			}
		}).await;
	Ok(())
}

fn read_readable(mut readable:impl Read)->AResult<Vec<u8>>{
	let mut contents=Vec::new();
	readable.read_to_end(&mut contents)?;
	Ok(contents)
}

async fn download_list(cookie:String,asset_id_file_map:AssetIDFileMap)->AResult<()>{
	let client=reqwest::Client::new();
	futures::stream::iter(asset_id_file_map.into_iter()
	.map(|(asset_id,file)|{
		let client=&client;
		let cookie=cookie.as_str();
		async move{
			let resp=client.get(format!("https://assetdelivery.roblox.com/v1/asset/?ID={}",asset_id))
			.header("Cookie",cookie)
			.send().await?;
			Ok((file,resp.bytes().await?))
		}
	}))
	.buffer_unordered(CONCURRENT_REQUESTS)
	.for_each(|b:AResult<_>|async{
			match b{
				Ok((dest,body))=>{
					let contents=match maybe_gzip_decode(&mut std::io::Cursor::new(body)){
						Ok(ReaderType::GZip(readable))=>read_readable(readable),
						Ok(ReaderType::Raw(readable))=>read_readable(readable),
						Err(e)=>Err(e),
					};
					match contents{
						Ok(data)=>match tokio::fs::write(dest,data).await{
							Err(e)=>eprintln!("fs error: {}",e),
							_=>(),
						},
						Err(e)=>eprintln!("gzip error: {}",e),
					};
				},
				Err(e)=>eprintln!("dl error: {}",e),
			}
		}).await;
	Ok(())
}

async fn download_page(client:&reqwest::Client,cookie:&str,asset_id:AssetID,cursor:Option<String>)->AResult<VersionPage>{
	let mut url=reqwest::Url::parse(format!("https://develop.roblox.com/v1/assets/{}/saved-versions",asset_id).as_str())?;
	//url borrow scope
	{
		let mut query=url.query_pairs_mut();//borrow here
		//query.append_pair("sortOrder","Asc");
		//query.append_pair("limit","100");
		//query.append_pair("count","100");
		match cursor.as_deref(){
			Some(next_page)=>{query.append_pair("cursor",next_page);}
			None=>(),
		}
	}
	println!("page url={}",url);
	let resp=client.get(url)
	.header("Cookie",cookie)
	.send().await?;
	Ok(resp.json::<VersionPage>().await?)
}

async fn get_version_history(client:&reqwest::Client,cookie:&str,asset_id:AssetID)->AResult<Vec<AssetVersion>>{
	let mut cursor:Option<String>=None;
	let mut asset_list=Vec::new();
	loop{
		let mut page=download_page(client,cookie,asset_id,cursor).await?;
		asset_list.append(&mut page.data);
		if page.nextPageCursor.is_none(){
			break;
		}
		cursor=page.nextPageCursor;
	}
	asset_list.sort_by(|a,b|a.assetVersionNumber.cmp(&b.assetVersionNumber));
	Ok(asset_list)
}

async fn download_asset_version(client:&reqwest::Client,cookie:&str,asset_id_str:&str,asset_version_str:&str)->AResult<reqwest::Response>{
	let mut url=reqwest::Url::parse("https://assetdelivery.roblox.com/v1/asset/")?;
	//url borrow scope
	{
		let mut query=url.query_pairs_mut();//borrow here
		query.append_pair("ID",asset_id_str);
		query.append_pair("version",asset_version_str);
	}
	println!("download url={}",url);
	for i in 0..8{
		let resp=client.get(url.clone())
		.header("Cookie",cookie)
		.send().await?;

		if !resp.status().is_success(){
			println!("request {} failed",i);
			continue;
		}

		return Ok(resp);
	}
	Err(anyhow::Error::msg("all requests failed"))
}

struct DownloadHistoryConfig{
	continue_from_versions:bool,
	end_version:Option<u64>,
	start_version:u64,
	output_folder:std::path::PathBuf,
	cookie:String,
	asset_id:AssetID,
}

async fn download_history(mut config:DownloadHistoryConfig)->AResult<()>{
	let mut asset_list_contents=std::collections::HashSet::new();
	let mut asset_list:Vec<AssetVersion>=Vec::new();
	if config.end_version.is_none()&&config.continue_from_versions{
		//load prexisting versions list
		let mut versions_path=config.output_folder.clone();
		versions_path.push("versions.json");
		match std::fs::File::open(versions_path){
			Ok(versions_file)=>asset_list.append(&mut serde_json::from_reader(versions_file)?),
			Err(e)=>match e.kind(){
				std::io::ErrorKind::NotFound=>return Err(anyhow::Error::msg("Cannot continue from versions.json - file does not exist")),
				_=>Err(e)?,
			}
		}
		//write down which versions are contained
		for asset_version in &asset_list{
			asset_list_contents.insert(asset_version.assetVersionNumber);
		}
		//find the highest number
		match asset_list.iter().map(|asset_version|asset_version.assetVersionNumber).max(){
			Some(max)=>{
				//count down contiguously until a number is missing
				for i in (1..=max).rev(){
					if !asset_list_contents.contains(&i){
						//that is end_version
						config.end_version=Some(i);
						break;
					}
				}
				//if all versions are contained, set start_version to the max + 1
				if config.end_version.is_none(){
					config.start_version=max+1;
				}
			},
			None=>Err(anyhow::Error::msg("Cannot continue from versions.json - there are no previous versions"))?,
		}
	}
	let client=reqwest::Client::new();

	let asset_id_string=config.asset_id.to_string();

	//limit concurrent downloads
	let mut join_set=tokio::task::JoinSet::new();

	//poll paged list of all asset versions
	let mut cursor:Option<String>=None;
	loop{
		let mut page=download_page(&client,config.cookie.as_str(),config.asset_id,cursor).await?;
		let client=&client;
		let cookie=config.cookie.clone();
		let asset_id_str=asset_id_string.clone();
		let output_folder=config.output_folder.clone();
		let data=&page.data;
		let asset_list_contents=&asset_list_contents;
		let join_set=&mut join_set;
		let error_catcher=||async move{
		let mut cancel_paging=false;
		for asset_version in data{
			let version_number=asset_version.assetVersionNumber;
			//skip assets beyond specified end_version
			if config.end_version.is_some_and(|v|v<version_number){
				continue;
			}
			//skip assets lower than start_version and cancel paging asset versions
			if version_number<config.start_version{
				cancel_paging=true;
				continue;//don't trust roblox returned order
			}
			//skip previously downloaded assets
			if asset_list_contents.contains(&version_number){
				continue;
			}
			while CONCURRENT_REQUESTS<=join_set.len(){
				join_set.join_next().await.unwrap()??;
			}
			let client=client.clone();
			let cookie=cookie.clone();
			let asset_id_str=asset_id_str.clone();
			let mut path=output_folder.clone();
			path.push(format!("{}_v{}.rbxl",config.asset_id,version_number));
			join_set.spawn(async move{
				let resp=download_asset_version(&client,cookie.as_str(),asset_id_str.as_str(),version_number.to_string().as_str()).await?;
				let contents=match maybe_gzip_decode(std::io::Cursor::new(resp.bytes().await?))?{
					ReaderType::GZip(readable)=>read_readable(readable)?,
					ReaderType::Raw(readable)=>read_readable(readable)?,
				};

				tokio::fs::write(path,contents).await?;

				Ok::<_,anyhow::Error>(())
			});
		}
		Ok::<_,anyhow::Error>(cancel_paging)
		};
		let cancel_paging=match error_catcher().await{
			Ok(cancel)=>cancel,
			Err(e)=>{
				println!("download error: {}",e);
				//cancel download and write versions
				true
			},
		};
		if page.nextPageCursor.is_none()||cancel_paging{
			for asset_version in page.data.into_iter(){
				if !(asset_list_contents.contains(&asset_version.assetVersionNumber)
				||config.end_version.is_some_and(|v|v<asset_version.assetVersionNumber)
				||asset_version.assetVersionNumber<config.start_version){
					asset_list.push(asset_version);
				}
			}
			break;
		}else{
			asset_list.append(&mut page.data);
		}
		cursor=page.nextPageCursor;
	}

	asset_list.sort_by(|a,b|a.assetVersionNumber.cmp(&b.assetVersionNumber));

	let mut path=config.output_folder.clone();
	path.set_file_name("versions.json");
	tokio::fs::write(path,serde_json::to_string(&asset_list)?).await?;

	while let Some(result)=join_set.join_next().await{
		result??;
	}

	Ok(())
}

fn load_dom<R:Read>(input:R)->AResult<rbx_dom_weak::WeakDom>{
	let mut buf=std::io::BufReader::new(input);
	let peek=std::io::BufRead::fill_buf(&mut buf)?;
	match &peek[0..4]{
		b"<rob"=>{
			match &peek[4..8]{
				b"lox!"=>return rbx_binary::from_reader(buf).map_err(anyhow::Error::msg),
				b"lox "=>return rbx_xml::from_reader_default(buf).map_err(anyhow::Error::msg),
				other=>Err(anyhow::Error::msg(format!("Unknown Roblox file type {:?}",other))),
			}
		},
		_=>Err(anyhow::Error::msg("unsupported file type")),
	}
}

#[derive(PartialEq)]
enum Class{
	Folder,
	ModuleScript,
	LocalScript,
	Script,
	Model,
}

struct TreeNode{
	name:String,
	referent:Ref,
	parent:Ref,
	class:Class,
	children:Vec<Ref>,
}
impl TreeNode{
	fn new(name:String,referent:Ref,parent:Ref,class:Class)->Self{
		Self{
			name,
			referent,
			parent,
			class,
			children:Vec::new(),
		}
	}
}

enum TrimStackInstruction{
	Referent(Ref),
	IncrementScript,
	DecrementScript,
}

enum WriteStackInstruction<'a>{
	Node(&'a TreeNode,u32),//(Node,NameTally)
	PushFolder(String),
	PopFolder,
	Destroy(Ref),
}

#[derive(Default)]
struct PropertiesOverride{
	name:Option<String>,
	class_name:Option<String>,
}
impl PropertiesOverride{
	fn is_some(&self)->bool{
		self.name.is_some()
		||self.class_name.is_some()
	}
}
impl std::fmt::Display for PropertiesOverride{
	fn fmt(&self,f:&mut std::fmt::Formatter<'_>)->std::fmt::Result{
		if let Some(name)=self.name.as_deref(){
			writeln!(f,"--! Properties.Name=\"{}\"",name)?;
		}
		if let Some(class_name)=self.class_name.as_deref(){
			writeln!(f,"--! Properties.ClassName=\"{}\"",class_name)?;
		}
		Ok(())
    }
}

fn sanitize<'a>(s:&'a str)->std::borrow::Cow<'a,str>{
	lazy_regex::regex!(r"[^a-zA-Z0-9._-]").replace_all(s,"_")
}

fn write_item(dom:&rbx_dom_weak::WeakDom,mut file:std::path::PathBuf,node:&TreeNode,node_name_override:String,mut properties:PropertiesOverride,style:DecompileStyle,write_models:bool,write_scripts:bool)->AResult<()>{
	file.push(sanitize(node_name_override.as_str()).as_ref());
	match node.class{
		Class::Folder=>(),
		Class::ModuleScript|Class::LocalScript|Class::Script=>{
			if !write_scripts{
				return Ok(())
			}

			//set extension
			match style{
				DecompileStyle::Rox=>assert!(file.set_extension("lua"),"could not set extension"),
				DecompileStyle::RoxRojo|DecompileStyle::Rojo=>{
					match properties.class_name.as_deref(){
						Some("LocalScript")=>{
							file.set_extension("client.lua");
							properties.class_name=None;
						},
						Some("Script")=>{
							file.set_extension("server.lua");
							properties.class_name=None;
						},
						// Some("ModuleScript")=>{
						// 	file.set_extension("module");
						// 	properties.class_name=None;
						// },
						None=>assert!(file.set_extension("lua"),"could not set extension"),
						Some(other)=>return Err(anyhow::Error::msg(format!("Attempt to write a {} as a script",other))),
					}
				}
			}

			if let Some(item)=dom.get_by_ref(node.referent){
				//TODO: delete disabled scripts
				if let Some(rbx_dom_weak::types::Variant::String(source))=item.properties.get("Source"){
					if properties.is_some(){
						//rox style
						let source=properties.to_string()+source.as_str();
						std::fs::write(file,source)?;
					}else{
						std::fs::write(file,source)?;
					}
				}
			}
		},
		Class::Model=>{
			if !write_models{
				return Ok(())
			}
			assert!(file.set_extension("rbxmx"));
			let output=std::io::BufWriter::new(std::fs::File::create(file)?);
			rbx_xml::to_writer_default(output,dom,&[node.referent])?;
		},
	}
	Ok(())
}

struct DecompiledContext{
	dom:rbx_dom_weak::WeakDom,
	tree_refs:std::collections::HashMap<rbx_dom_weak::types::Ref,TreeNode>,
}

fn generate_decompiled_context<R:Read>(input:R)->AResult<DecompiledContext>{
	let dom=load_dom(input)?;

	let mut tree_refs=std::collections::HashMap::new();
	tree_refs.insert(dom.root_ref(),TreeNode::new(
		"src".to_string(),
		dom.root_ref(),
		Ref::none(),
		Class::Folder
	));

	//run rules
	let mut stack=vec![dom.root()];
	while let Some(item)=stack.pop(){
		let class=match item.class.as_str(){
			"ModuleScript"=>Class::ModuleScript,
			"LocalScript"=>Class::LocalScript,
			"Script"=>Class::Script,
			"Model"=>Class::Model,
			_=>Class::Folder,
		};
		let skip=match class{
			Class::Model=>true,
			_=>false,
		};
		if let Some(parent_node)=tree_refs.get_mut(&item.parent()){
			let referent=item.referent();
			let node=TreeNode::new(item.name.clone(),referent,parent_node.referent,class);
			parent_node.children.push(referent);
			tree_refs.insert(referent,node);
		}
		//look no further, turn this node and all its children into a model
		if skip{
			continue;
		}
		for &referent in item.children(){
			if let Some(c)=dom.get_by_ref(referent){
				stack.push(c);
			}
		}
	}

	//trim empty folders
	let mut script_count=0;
	let mut stack:Vec<TrimStackInstruction>=tree_refs.get(&dom.root_ref()).unwrap().children
	.iter().map(|&c|TrimStackInstruction::Referent(c)).collect();
	while let Some(instruction)=stack.pop(){
		match instruction{
			TrimStackInstruction::IncrementScript=>script_count+=1,
			TrimStackInstruction::DecrementScript=>script_count-=1,
			TrimStackInstruction::Referent(referent)=>{
				let mut delete=None;
				if let Some(node)=tree_refs.get_mut(&referent){
					if node.class==Class::Folder&&script_count!=0{
						node.class=Class::Model
					}
					if node.class==Class::Folder&&node.children.len()==0{
						delete=Some(node.parent);
					}else{
						//how the hell do I do this better without recursion
						let is_script=match node.class{
							Class::ModuleScript|Class::LocalScript|Class::Script=>true,
							_=>false,
						};
						//stack is popped from back
						if is_script{
							stack.push(TrimStackInstruction::DecrementScript);
						}
						for &child_referent in &node.children{
							stack.push(TrimStackInstruction::Referent(child_referent));
						}
						if is_script{
							stack.push(TrimStackInstruction::IncrementScript);
						}
					}
				}
				//trim referent
				if let Some(parent_ref)=delete{
					let parent_node=tree_refs.get_mut(&parent_ref)
					.expect("parent_ref does not exist in tree_refs");
					parent_node.children.remove(
						parent_node.children.iter()
						.position(|&r|r==referent)
						.expect("parent.children does not contain referent")
					);
					tree_refs.remove(&referent);
				}
			},
		}
	}

	Ok(DecompiledContext{
		dom,
		tree_refs,
	})
}

struct WriteConfig{
	style:DecompileStyle,
	output_folder:std::path::PathBuf,
	write_template:bool,
	write_models:bool,
	write_scripts:bool,
}

async fn write_files(config:WriteConfig,mut context:DecompiledContext)->AResult<()>{
	let mut write_queue=Vec::new();
	let mut destroy_queue=Vec::new();

	let mut name_tally=std::collections::HashMap::<String,u32>::new();
	let mut folder=config.output_folder.clone();
	let mut stack=vec![WriteStackInstruction::Node(context.tree_refs.get(&context.dom.root_ref()).unwrap(),0)];
	while let Some(instruction)=stack.pop(){
		match instruction{
			WriteStackInstruction::PushFolder(component)=>folder.push(component),
			WriteStackInstruction::PopFolder=>assert!(folder.pop(),"weirdness"),
			WriteStackInstruction::Destroy(referent)=>destroy_queue.push(referent),
			WriteStackInstruction::Node(node,name_count)=>{
				//track properties that must be overriden to compile folder structure back into a place file
				let mut properties=PropertiesOverride::default();
				let has_children=node.children.len()!=0;
				match node.class{
					Class::Folder=>(),
					Class::ModuleScript=>(),//.lua files are ModuleScript by default
					Class::LocalScript=>properties.class_name=Some("LocalScript".to_string()),
					Class::Script=>properties.class_name=Some("Script".to_string()),
					Class::Model=>(),
				}
				let name_override=if 0<name_count{
					properties.name=Some(node.name.clone());
					format!("{}_{}",node.name,name_count)
				}else{
					node.name.clone()
				};

				if has_children{
					//push temp subfolder
					let mut subfolder=folder.clone();
					subfolder.push(sanitize(name_override.as_str()).as_ref());
					//make folder
					tokio::fs::create_dir(subfolder.clone()).await?;

					let name_final=match config.style{
						DecompileStyle::Rox
						|DecompileStyle::RoxRojo=>name_override.clone(),
						DecompileStyle::Rojo=>"init".to_owned(),
					};

					//write item in subfolder
					write_queue.push((subfolder,node,name_final,properties,config.style));
				}else{
					//write item
					write_queue.push((folder.clone(),node,name_override.clone(),properties,config.style));
				}
				//queue item to be deleted from dom after child objects are handled (stack is popped from the back)
				match node.class{
					Class::Folder=>(),
					_=>stack.push(WriteStackInstruction::Destroy(node.referent)),
				}
				if has_children{
					stack.push(WriteStackInstruction::PopFolder);
					name_tally.clear();
					for referent in &node.children{
						if let Some(c)=context.tree_refs.get(referent){
							let v=name_tally.entry(c.name.clone()).and_modify(|v|*v+=1).or_default();
							stack.push(WriteStackInstruction::Node(c,*v));
						}
					}
					stack.push(WriteStackInstruction::PushFolder(sanitize(name_override.as_str()).to_string()));
				}
			},
		}
	}

	//run the async
	{
		let dom=&context.dom;
		let write_models=config.write_models;
		let write_scripts=config.write_scripts;
		let results:Vec<AResult<()>>=rayon::iter::ParallelIterator::collect(rayon::iter::ParallelIterator::map(rayon::iter::IntoParallelIterator::into_par_iter(write_queue),|(write_path,node,node_name_override,properties,style)|{
			write_item(&dom,write_path,node,node_name_override,properties,style,write_models,write_scripts)
		}));
		for result in results{
			result?;
		}
	}

	//run the destroy
	for destroy_ref in destroy_queue{
		context.dom.destroy(destroy_ref);
	}

	//write what remains in template.rbxlx
	if config.write_template{
		let mut file=config.output_folder.clone();
		file.push("template");
		assert!(file.set_extension("rbxlx"));
		let output=std::io::BufWriter::new(std::fs::File::create(file)?);
		rbx_xml::to_writer_default(output,&context.dom,&[context.dom.root_ref()])?;
	}

	Ok(())
}

struct DecompileConfig{
	style:DecompileStyle,
	input_file:std::path::PathBuf,
	output_folder:std::path::PathBuf,
	write_template:bool,
	write_models:bool,
	write_scripts:bool,
}

async fn decompile(config:DecompileConfig)->AResult<()>{
	//rules:
	//Class Script|LocalScript|ModuleScript->$Name.lua
	//Class Model->$Name.rbxmx
	//overrides.json per-folder [Override{name,class}]
	//Everything else goes into template.rbxlx

	//read file
	let context=generate_decompiled_context(std::io::BufReader::new(std::fs::File::open(config.input_file)?))?;

	//generate folders, models, and scripts
	//delete models and scripts from dom
	write_files(WriteConfig{
		style:config.style,
		output_folder:config.output_folder,
		write_template:config.write_template,
		write_models:config.write_models,
		write_scripts:config.write_scripts,
	},context).await?;

	Ok(())
}

struct WriteCommitConfig{
	git_committer_name:String,
	git_committer_email:String,
	output_folder:std::path::PathBuf,
	style:DecompileStyle,
	write_template:bool,
	write_models:bool,
	write_scripts:bool,
}

async fn write_commit(config:WriteCommitConfig,b:Result<AResult<(AssetVersion,DecompiledContext)>,tokio::task::JoinError>,repo:&git2::Repository)->AResult<()>{
	let (asset_version,context)=b??;
	println!("writing files for version {}",asset_version.assetVersionNumber);

	//clean output dir
	if config.write_models||config.write_scripts{
		let mut src=config.output_folder.clone();
		src.push("src");
		match std::fs::remove_dir_all(src){
			Ok(())=>(),
			Err(e)=>println!("remove_dir_all src failed {}",e),
		}
	}
	if config.write_template{
		let mut template=config.output_folder.clone();
		template.push("template.rbxlx");
		match std::fs::remove_file(template){
			Ok(())=>(),
			Err(e)=>println!("remove_file template.rbxlx failed {}",e),
		}
	}

	//write files
	write_files(WriteConfig{
		style:config.style,
		output_folder:config.output_folder.clone(),
		write_template:config.write_template,
		write_models:config.write_models,
		write_scripts:config.write_scripts,
	},context).await?;

	let date=asset_version.created;
	//let sig=repo.signature()?; //this pulls default name and email
	let sig=git2::Signature::new(config.git_committer_name.as_str(),config.git_committer_email.as_str(),&git2::Time::new(date.timestamp(),0)).unwrap();
	let tree_id={
		let mut tree_index = repo.index()?;
		tree_index.add_all([config.output_folder.as_path()].iter(),git2::IndexAddOption::DEFAULT,None)?;
		match tree_index.update_all([config.output_folder.as_path()].iter(),None){
			Ok(_)=>(),
			Err(e)=>println!("tree_index.update_all error: {}",e),
		}
		tree_index.write()?;
		tree_index.write_tree()?
	};
	let tree=repo.find_tree(tree_id)?;

	let mut parents=Vec::new();

	match repo.head(){
		Ok(reference)=>{
			let commit=reference.peel_to_commit()?;

			//test tree against commit tree to see if there is any changes
			let commit_tree=commit.tree()?;
			let diff=repo.diff_tree_to_tree(Some(&commit_tree),Some(&tree),None)?;
			if diff.deltas().count()==0{
				println!("no changes");
				return Ok(());
			}

			parents.push(commit);
		},
		Err(e)=>println!("repo head error {:?}",e),
	};

	repo.commit(
		Some("HEAD"),//update_ref
		&sig,//author
		&sig,//commiter
		&format!("v{}", asset_version.assetVersionNumber),//message
		&tree,//tree (basically files)
		parents.iter().collect::<Vec<&git2::Commit<'_>>>().as_slice(),//parents
	)?;

	//commit
	Ok(())
}

struct DecompileHistoryConfig{
	git_committer_name:String,
	git_committer_email:String,
	input_folder:std::path::PathBuf,
	style:DecompileStyle,
	output_folder:std::path::PathBuf,
	write_template:bool,
	write_models:bool,
	write_scripts:bool,
}

async fn decompile_history_into_git(config:DecompileHistoryConfig)->AResult<()>{
	//use prexisting versions list
	let mut versions_path=config.input_folder.clone();
	versions_path.push("versions.json");
	let asset_list:Vec<AssetVersion>=serde_json::from_reader(std::fs::File::open(versions_path)?)?;

	let repo=git2::Repository::init(config.output_folder.clone())?;

	//decompile all versions
	futures::stream::iter(asset_list.into_iter()
	.map(|asset_version|{
		let mut file_path=config.input_folder.clone();
		tokio::task::spawn_blocking(move||{
			file_path.push(format!("{}_v{}.rbxl",asset_version.assetId,asset_version.assetVersionNumber));
			let file=std::fs::File::open(file_path)?;
			let contents=generate_decompiled_context(file)?;
			Ok::<_,anyhow::Error>((asset_version,contents))
		})
	}))
	.buffered(CONCURRENT_DECODE)
	.for_each(|join_handle_result|async{
		match write_commit(WriteCommitConfig{
			git_committer_name:config.git_committer_name.clone(),
			git_committer_email:config.git_committer_email.clone(),
			style:config.style,
			output_folder:config.output_folder.clone(),
			write_template:config.write_template,
			write_models:config.write_models,
			write_scripts:config.write_scripts,
		},join_handle_result,&repo).await{
			Ok(())=>(),
			Err(e)=>println!("decompile/write/commit error: {}",e),
		}
	}).await;
	Ok(())
}

struct DownloadAndDecompileHistoryConfig{
	cookie:String,
	asset_id:AssetID,
	git_committer_name:String,
	git_committer_email:String,
	style:DecompileStyle,
	output_folder:std::path::PathBuf,
	write_template:bool,
	write_models:bool,
	write_scripts:bool,
}

async fn download_and_decompile_history_into_git(config:DownloadAndDecompileHistoryConfig)->AResult<()>{
	let client=reqwest::Client::new();

	//poll paged list of all asset versions
	let asset_list=get_version_history(&client,&config.cookie.as_str(),config.asset_id).await?;

	let repo=git2::Repository::init(config.output_folder.clone())?;

	//download all versions
	let asset_id_string=config.asset_id.to_string();
	futures::stream::iter(asset_list.into_iter()
	.map(|asset_version|{
		let client=client.clone();
		let cookie=config.cookie.clone();
		let asset_id_str=asset_id_string.clone();
		tokio::task::spawn(async move{
			let resp=download_asset_version(&client,cookie.as_str(),asset_id_str.as_str(),asset_version.assetVersionNumber.to_string().as_str()).await?;
			let contents=match maybe_gzip_decode(std::io::Cursor::new(resp.bytes().await?))?{
				ReaderType::GZip(readable)=>generate_decompiled_context(readable)?,
				ReaderType::Raw(readable)=>generate_decompiled_context(readable)?,
			};
			Ok::<_,anyhow::Error>((asset_version,contents))
		})
	}))
	.buffered(CONCURRENT_DECODE)
	.for_each(|join_handle_result|async{
		match write_commit(WriteCommitConfig{
			style:config.style,
			git_committer_name:config.git_committer_name.clone(),
			git_committer_email:config.git_committer_email.clone(),
			output_folder:config.output_folder.clone(),
			write_template:config.write_template,
			write_models:config.write_models,
			write_scripts:config.write_scripts,
		},join_handle_result,&repo).await{
			Ok(())=>(),
			Err(e)=>println!("download/unzip/decompile/write/commit error: {}",e),
		}
	}).await;
	Ok(())
}

fn compile(_folder:std::path::PathBuf,_file:std::path::PathBuf)->AResult<()>{
	Ok(())
}