use crate::Project;
use futures::FutureExt;
use std::{
	ffi::OsStr,
	fmt::{Debug, Display, Formatter},
	path::PathBuf,
	process::Stdio,
};
use tokio::{
	io::{AsyncBufReadExt, BufReader},
	process::Command,
};
use tracing::instrument;

/// Script names used by pesde
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub enum ScriptName {
	/// Generates a config for syncing tools for Roblox. For example, for Rojo it should create a `default.project.json` file
	RobloxSyncConfigGenerator,
	/// Prints a sourcemap for a Wally package, used for finding the library export file
	#[cfg(feature = "wally-compat")]
	SourcemapGenerator,
}

impl Display for ScriptName {
	fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
		match self {
			ScriptName::RobloxSyncConfigGenerator => write!(f, "roblox_sync_config_generator"),
			#[cfg(feature = "wally-compat")]
			ScriptName::SourcemapGenerator => write!(f, "sourcemap_generator"),
		}
	}
}

/// Finds a script in the project, whether it be in the current package or it's workspace
pub async fn find_script(
	project: &Project,
	script_name: ScriptName,
) -> Result<Option<PathBuf>, errors::FindScriptError> {
	let script_name_str = script_name.to_string();

	let script_path = match project
		.deser_manifest()
		.await?
		.scripts
		.remove(&script_name_str)
	{
		Some(script) => script.to_path(project.package_dir()),
		None => match project
			.deser_workspace_manifest()
			.await?
			.and_then(|mut manifest| manifest.scripts.remove(&script_name_str))
		{
			Some(script) => script.to_path(project.workspace_dir().unwrap()),
			None => {
				return Ok(None);
			}
		},
	};

	Ok(Some(script_path))
}

#[allow(unused_variables)]
pub(crate) trait ExecuteScriptHooks {
	fn not_found(&self, script: ScriptName) {}
}

#[instrument(skip(project, hooks), level = "debug")]
pub(crate) async fn execute_script<
	A: IntoIterator<Item = S> + Debug,
	S: AsRef<OsStr> + Debug,
	H: ExecuteScriptHooks,
>(
	script_name: ScriptName,
	project: &Project,
	hooks: H,
	args: A,
	return_stdout: bool,
) -> Result<Option<String>, errors::ExecuteScriptError> {
	let Some(script_path) = find_script(project, script_name).await? else {
		hooks.not_found(script_name);
		return Ok(None);
	};

	match Command::new("lune")
		.arg("run")
		.arg(script_path.as_os_str())
		.arg("--")
		.args(args)
		.current_dir(project.package_dir())
		.stdin(Stdio::inherit())
		.stdout(Stdio::piped())
		.stderr(Stdio::piped())
		.spawn()
	{
		Ok(mut child) => {
			let mut stdout = BufReader::new(child.stdout.take().unwrap()).lines();
			let mut stderr = BufReader::new(child.stderr.take().unwrap()).lines();

			let mut stdout_str = String::new();

			loop {
				tokio::select! {
					Some(line) = stdout.next_line().map(Result::transpose) => match line {
						Ok(line) => {
							if return_stdout {
								stdout_str.push_str(&line);
								stdout_str.push('\n');
							} else {
								tracing::info!("[{script_name}]: {line}");
							}
						}
						Err(e) => {
							tracing::error!("ERROR IN READING STDOUT OF {script_name}: {e}");
						}
					},
					Some(line) = stderr.next_line().map(Result::transpose) => match line {
						Ok(line) => {
							tracing::error!("[{script_name}]: {line}");
						}
						Err(e) => {
							tracing::error!("ERROR IN READING STDERR OF {script_name}: {e}");
						}
					},
					else => break,
				}
			}

			if return_stdout {
				Ok(Some(stdout_str))
			} else {
				Ok(None)
			}
		}
		Err(e) if e.kind() == std::io::ErrorKind::NotFound => {
			tracing::warn!("Lune could not be found in PATH: {e}");

			Ok(None)
		}
		Err(e) => Err(e.into()),
	}
}

/// Errors that can occur when using scripts
pub mod errors {
	use thiserror::Error;

	/// Errors that can occur when finding a script
	#[derive(Debug, Error)]
	pub enum FindScriptError {
		/// Reading the manifest failed
		#[error("error reading manifest")]
		ManifestRead(#[from] crate::errors::ManifestReadError),

		/// An IO error occurred
		#[error("IO error")]
		Io(#[from] std::io::Error),
	}

	/// Errors which can occur while executing a script
	#[derive(Debug, Error)]
	pub enum ExecuteScriptError {
		/// Finding the script failed
		#[error("finding the script failed")]
		FindScript(#[from] FindScriptError),

		/// An IO error occurred
		#[error("IO error")]
		Io(#[from] std::io::Error),
	}
}