use std::{ffi::OsStr, fs::{FileType, Metadata}, hash::{BuildHasher, Hash, Hasher}, ops::Deref};

use anyhow::Result;
use tokio::fs;
use yazi_shared::{SyncCell, theme::IconCache, url::{Url, Urn, UrnBuf}};

use crate::Cha;

#[derive(Clone, Debug, Default)]
pub struct File {
	pub url:     Url,
	pub cha:     Cha,
	pub link_to: Option<Url>,
	pub icon:    SyncCell<IconCache>,
}

impl Deref for File {
	type Target = Cha;

	#[inline]
	fn deref(&self) -> &Self::Target { &self.cha }
}

impl File {
	#[inline]
	pub async fn from(url: Url) -> Result<Self> {
		let meta = fs::symlink_metadata(&url).await?;
		Ok(Self::from_meta(url, meta).await)
	}

	#[inline]
	pub async fn from_meta(url: Url, meta: Metadata) -> Self {
		let link_to =
			if meta.is_symlink() { fs::read_link(&url).await.map(Url::from).ok() } else { None };

		let cha = Cha::new(&url, meta).await;

		Self { url, cha, link_to, icon: Default::default() }
	}

	#[inline]
	pub fn from_dummy(url: Url, ft: Option<FileType>) -> Self {
		Self {
			url,
			cha: ft.map_or_else(Cha::dummy, Cha::from),
			link_to: None,
			icon: Default::default(),
		}
	}

	#[inline]
	pub fn hash(&self) -> u64 {
		let mut h = foldhash::fast::FixedState::default().build_hasher();
		self.url.hash(&mut h);
		h.write_u8(0);
		self.cha.len.hash(&mut h);
		h.write_u8(0);
		self.cha.mtime.hash(&mut h);
		h.write_u8(0);
		self.cha.btime.hash(&mut h);
		h.finish()
	}

	#[inline]
	pub fn rebase(&self, parent: &Url) -> Self {
		Self {
			url:     self.url.rebase(parent),
			cha:     self.cha,
			link_to: self.link_to.clone(),
			icon:    Default::default(),
		}
	}
}

impl File {
	// --- Url
	#[inline]
	pub fn url_owned(&self) -> Url { self.url.to_owned() }

	#[inline]
	pub fn urn(&self) -> &Urn { self.url.urn() }

	#[inline]
	pub fn urn_owned(&self) -> UrnBuf { self.url.urn_owned() }

	#[inline]
	pub fn name(&self) -> &OsStr { self.url.name() }

	#[inline]
	pub fn stem(&self) -> Option<&OsStr> { self.url.file_stem() }
}