pub mod parse_folder;

use std::cell::RefCell;
use std::fs::File;
use std::io::{Read, Write};
use std::process::{Command, ExitCode};
use std::rc::Rc;

use async_fn_stream::try_stream;
use camino::Utf8PathBuf;
use clap::{Parser, Subcommand};
use futures::future::LocalBoxFuture;
use futures::{FutureExt, Stream, TryStreamExt, io};
use itertools::Itertools;
use orchid_base::error::{try_with_reporter, with_reporter};
use orchid_base::format::{FmtCtxImpl, Format, fmt, fmt_v, take_first};
use orchid_base::interner::local_interner::local_interner;
use orchid_base::interner::{is, with_interner};
use orchid_base::location::SrcRange;
use orchid_base::logging::{LogStrategy, Logger, with_logger};
use orchid_base::name::{NameLike, VPath};
use orchid_base::parse::{Import, Snippet};
use orchid_base::sym;
use orchid_base::tree::{Token, ttv_fmt};
use orchid_host::ctx::{Ctx, JoinHandle, Spawner};
use orchid_host::execute::{ExecCtx, ExecResult};
use orchid_host::expr::ExprKind;
use orchid_host::extension::Extension;
use orchid_host::lex::lex;
use orchid_host::parse::{HostParseCtxImpl, parse_item, parse_items};
use orchid_host::parsed::{Item, ItemKind, ParsTokTree, ParsedMember, ParsedModule};
use orchid_host::subprocess::ext_command;
use orchid_host::system::init_systems;
use orchid_host::tree::{MemberKind, Module, RootData};
use substack::Substack;
use tokio::io::{AsyncBufReadExt, BufReader, stdin};
use tokio::task::{LocalSet, spawn_local};

use crate::parse_folder::parse_folder;

#[derive(Parser, Debug)]
#[command(version, about, long_about)]
pub struct Args {
	#[arg(short, long, env = "ORCHID_EXTENSIONS", value_delimiter = ';')]
	extension: Vec<Utf8PathBuf>,
	#[arg(short, long, env = "ORCHID_DEFAULT_SYSTEMS", value_delimiter = ';')]
	system: Vec<String>,
	#[arg(short, long)]
	logs: bool,
	#[arg(short, long)]
	msg_logs: bool,
	#[command(subcommand)]
	command: Commands,
}

#[derive(Subcommand, Debug)]
pub enum Commands {
	Lex {
		#[arg(short, long)]
		file: Utf8PathBuf,
	},
	Parse {
		#[arg(short, long)]
		file: Utf8PathBuf,
	},
	Repl,
	ModTree {
		#[arg(long)]
		proj: Option<Utf8PathBuf>,
		#[arg(long)]
		prefix: Option<String>,
	},
	Exec {
		#[arg(long)]
		proj: Option<Utf8PathBuf>,
		#[arg()]
		code: String,
	},
}

fn get_all_extensions<'a>(
	args: &'a Args,
	ctx: &'a Ctx,
) -> impl Stream<Item = io::Result<Extension>> + 'a {
	try_stream(async |mut cx| {
		for ext_path in args.extension.iter() {
			let exe = if cfg!(windows) { ext_path.with_extension("exe") } else { ext_path.clone() };
			let init = ext_command(Command::new(exe.as_os_str()), ctx.clone()).await?;
			cx.emit(Extension::new(init, ctx.clone()).await?).await;
		}
		Ok(cx)
	})
}

struct JoinHandleImpl(tokio::task::JoinHandle<()>);
impl JoinHandle for JoinHandleImpl {
	fn abort(&self) { self.0.abort() }
	fn join(self: Box<Self>) -> LocalBoxFuture<'static, ()> {
		Box::pin(async { self.0.await.unwrap() })
	}
}

struct SpawnerImpl;
impl Spawner for SpawnerImpl {
	fn spawn_obj(&self, fut: LocalBoxFuture<'static, ()>) -> Box<dyn JoinHandle> {
		Box::new(JoinHandleImpl(spawn_local(fut)))
	}
}

#[tokio::main]
async fn main() -> io::Result<ExitCode> {
	eprintln!("orcx launched");
	let exit_code = Rc::new(RefCell::new(ExitCode::SUCCESS));
	let local_set = LocalSet::new();
	let exit_code1 = exit_code.clone();
	let args = Args::parse();
	let logger = Logger::new(if args.logs { LogStrategy::StdErr } else { LogStrategy::Discard });
	let cx_logger = logger.clone();
	let msg_logger =
		Logger::new(if args.msg_logs { LogStrategy::StdErr } else { LogStrategy::Discard });
	local_set.spawn_local(async move {
		let ctx = &Ctx::new(msg_logger.clone(), SpawnerImpl);
		let extensions = get_all_extensions(&args, ctx).try_collect::<Vec<Extension>>().await.unwrap();
		match args.command {
			Commands::Lex { file } => {
				let (_, systems) = init_systems(&args.system, &extensions).await.unwrap();
				let mut file = File::open(file.as_std_path()).unwrap();
				let mut buf = String::new();
				file.read_to_string(&mut buf).unwrap();
				let lexemes = lex(is(&buf).await, sym!(usercode), &systems, ctx).await.unwrap();
				println!("{}", take_first(&ttv_fmt(&lexemes, &FmtCtxImpl::default()).await, true))
			},
			Commands::Parse { file } => {
				let (_, systems) = init_systems(&args.system, &extensions).await.unwrap();
				let mut file = File::open(file.as_std_path()).unwrap();
				let mut buf = String::new();
				file.read_to_string(&mut buf).unwrap();
				let lexemes = lex(is(&buf).await, sym!(usercode), &systems, ctx).await.unwrap();
				let Some(first) = lexemes.first() else {
					println!("File empty!");
					return;
				};
				let pctx = HostParseCtxImpl { systems: &systems, ctx: ctx.clone(), src: sym!(usercode) };
				let snip = Snippet::new(first, &lexemes);
				match with_reporter(parse_items(&pctx, Substack::Bottom, snip)).await.unwrap() {
					Err(errv) => {
						eprintln!("{errv}");
						*exit_code1.borrow_mut() = ExitCode::FAILURE;
					},
					Ok(ptree) if ptree.is_empty() => {
						eprintln!("File empty only after parsing, but no errors were reported");
						*exit_code1.borrow_mut() = ExitCode::FAILURE;
					},
					Ok(ptree) =>
						for item in ptree {
							println!("{}", take_first(&item.print(&FmtCtxImpl::default()).await, true))
						},
				};
			},
			Commands::Repl => {
				let mut counter = 0;
				let mut imports = Vec::new();
				let usercode_path = sym!(usercode);
				let mut stdin = BufReader::new(stdin());
				loop {
					counter += 1;
					let (mut root, systems) = init_systems(&args.system, &extensions).await.unwrap();
					print!("\\.> ");
					std::io::stdout().flush().unwrap();
					let mut prompt = String::new();
					stdin.read_line(&mut prompt).await.unwrap();
					let name = is(&format!("_{counter}")).await;
					let path = usercode_path.suffix([name.clone()]).await;
					let mut lexemes =
						lex(is(prompt.trim()).await, path.clone(), &systems, ctx).await.unwrap();
					let Some(discr) = lexemes.first() else { continue };
					if args.logs {
						println!(
							"lexed: {}",
							take_first(&ttv_fmt(&lexemes, &FmtCtxImpl::default()).await, true)
						);
					}
					let prefix_sr = SrcRange::zw(path.clone(), 0);
					let process_lexemes = async |lexemes: &[ParsTokTree]| {
						let snippet = Snippet::new(&lexemes[0], lexemes);
						let parse_ctx =
							HostParseCtxImpl { ctx: ctx.clone(), src: path.clone(), systems: &systems[..] };
						match try_with_reporter(parse_item(&parse_ctx, Substack::Bottom, vec![], snippet)).await
						{
							Ok(items) => Some(items),
							Err(e) => {
								eprintln!("{e}");
								None
							},
						}
					};
					let add_imports = |items: &mut Vec<Item>, imports: &[Import]| {
						items.extend(imports.iter().map(|import| Item::new(import.sr.clone(), import.clone())));
					};
					if discr.is_kw(is("import").await) {
						let Some(import_lines) = process_lexemes(&lexemes).await else { continue };
						imports.extend(import_lines.into_iter().map(|it| match it.kind {
							ItemKind::Import(imp) => imp,
							_ => panic!("Expected imports from import line"),
						}));
						continue;
					}
					if !discr.is_kw(is("let").await) {
						let prefix = [is("export").await, is("let").await, name.clone(), is("=").await];
						lexemes.splice(0..0, prefix.map(|n| Token::Name(n).at(prefix_sr.clone())));
					}
					let Some(mut new_lines) = process_lexemes(&lexemes).await else { continue };
					let const_decl = new_lines.iter().exactly_one().expect("Multiple lines from let");
					let input_sr = const_decl.sr.map_range(|_| 0..0);
					let const_name = match &const_decl.kind {
						ItemKind::Member(ParsedMember { name: const_name, .. }) => const_name.clone(),
						_ => panic!("Expected exactly one constant declaration from let"),
					};
					add_imports(&mut new_lines, &imports);
					imports.push(Import::new(input_sr.clone(), VPath::new(path.segs()), const_name.clone()));
					let new_module = ParsedModule::new(true, new_lines);
					match with_reporter(root.add_parsed(&new_module, path.clone())).await {
						Ok(new) => root = new,
						Err(errv) => {
							eprintln!("{errv}");
							*exit_code1.borrow_mut() = ExitCode::FAILURE;
							return;
						},
					}
					eprintln!("parsed");
					let entrypoint =
						ExprKind::Const(path.suffix([const_name.clone()]).await).at(input_sr.pos());
					let mut xctx = ExecCtx::new(root.clone(), entrypoint).await;
					eprintln!("executed");
					xctx.set_gas(Some(1000));
					xctx.execute().await;
					match xctx.result() {
						ExecResult::Value(val) => println!(
							"{const_name} = {}",
							take_first(&val.print(&FmtCtxImpl::default()).await, false)
						),
						ExecResult::Err(e) => println!("error: {e}"),
						ExecResult::Gas(_) => println!("Ran out of gas!"),
					}
				}
			},
			Commands::ModTree { proj, prefix } => {
				let (mut root, _systems) = init_systems(&args.system, &extensions).await.unwrap();
				if let Some(proj_path) = proj {
					let path = proj_path.into_std_path_buf();
					match try_with_reporter(parse_folder(&root, path, sym!(src), ctx.clone())).await {
						Ok(r) => root = r,
						Err(e) => {
							eprintln!("{e}");
							*exit_code1.borrow_mut() = ExitCode::FAILURE;
							return;
						},
					}
				}
				let prefix = match prefix {
					Some(pref) => VPath::parse(&pref).await,
					None => VPath::new([]),
				};
				let root_data = root.0.read().await;
				print_mod(&root_data.root, prefix, &root_data).await;
				async fn print_mod(module: &Module, path: VPath, root: &RootData) {
					let indent = "  ".repeat(path.len());
					for (key, tgt) in &module.imports {
						match tgt {
							Ok(tgt) => println!("{indent}import {key} => {}", tgt.target),
							Err(opts) => println!(
								"{indent}import {key} conflicts between {}",
								opts.iter().map(|i| &i.target).join(" ")
							),
						}
					}
					for (key, mem) in &module.members {
						let new_path = path.clone().name_with_suffix(key.clone()).to_sym().await;
						match mem.kind(root.ctx.clone(), &root.consts).await {
							MemberKind::Module(module) => {
								println!("{indent}module {key} {{");
								print_mod(module, VPath::new(new_path.segs()), root).boxed_local().await;
								println!("{indent}}}")
							},
							MemberKind::Const => {
								let value = root.consts.get(&new_path).expect("Missing const!");
								println!("{indent}const {key} = {}", fmt(value).await)
							},
						}
					}
				}
			},
			Commands::Exec { proj, code } => {
				eprintln!("exec branch");
				let path = sym!(usercode);
				let prefix_sr = SrcRange::zw(path.clone(), 0);
				let (mut root, systems) = init_systems(&args.system, &extensions).await.unwrap();
				if let Some(proj_path) = proj {
					let path = proj_path.into_std_path_buf();
					match try_with_reporter(parse_folder(&root, path, sym!(src), ctx.clone())).await {
						Ok(r) => root = r,
						Err(e) => {
							eprintln!("{e}");
							*exit_code1.borrow_mut() = ExitCode::FAILURE;
							return;
						},
					}
				}
				let mut lexemes = match lex(is(code.trim()).await, path.clone(), &systems, ctx).await {
					Ok(lexemes) => {
						if args.logs {
							println!("lexed: {}", fmt_v::<ParsTokTree>(lexemes.iter()).await.join(" "));
						}
						lexemes
					},
					Err(e) => {
						eprintln!("{e}");
						*exit_code1.borrow_mut() = ExitCode::FAILURE;
						return;
					},
				};
				let parse_ctx =
					HostParseCtxImpl { ctx: ctx.clone(), src: path.clone(), systems: &systems[..] };
				let prefix = [is("export").await, is("let").await, is("entrypoint").await, is("=").await];
				lexemes.splice(0..0, prefix.map(|n| Token::Name(n).at(prefix_sr.clone())));
				let snippet = Snippet::new(&lexemes[0], &lexemes);
				let entrypoint = match try_with_reporter(parse_item(
					&parse_ctx,
					Substack::Bottom,
					vec![],
					snippet,
				))
				.await
				{
					Ok(items) => ParsedModule::new(true, items),
					Err(e) => {
						eprintln!("{e}");
						*exit_code1.borrow_mut() = ExitCode::FAILURE;
						return;
					},
				};
				let root = match with_reporter(root.add_parsed(&entrypoint, path.clone())).await {
					Err(e) => {
						eprintln!("{e}");
						*exit_code1.borrow_mut() = ExitCode::FAILURE;
						return;
					},
					Ok(new_root) => new_root,
				};
				let expr = ExprKind::Const(sym!(usercode::entrypoint)).at(prefix_sr.pos());
				let mut xctx = ExecCtx::new(root, expr).await;
				xctx.set_gas(Some(10_000));
				xctx.execute().await;
				match xctx.result() {
					ExecResult::Value(val) =>
						println!("{}", take_first(&val.print(&FmtCtxImpl::default()).await, false)),
					ExecResult::Err(e) => println!("error: {e}"),
					ExecResult::Gas(_) => println!("Ran out of gas!"),
				}
			},
		}
	});
	with_interner(local_interner(), with_logger(cx_logger, local_set)).await;
	let x = *exit_code.borrow();
	Ok(x)
}