use crate::{
	components::{
		visibility_blocking, CommandBlocking, CommandInfo, Component,
		DrawableComponent, EventState,
	},
	keys::SharedKeyConfig,
	strings,
	ui::{self, style::SharedTheme},
};
use anyhow::{anyhow, bail, Result};
use asyncgit::sync::{
	get_config_string, utils::repo_work_dir, RepoPath,
};
use crossterm::{
	event::Event,
	terminal::{EnterAlternateScreen, LeaveAlternateScreen},
	ExecutableCommand,
};
use ratatui::{
	backend::Backend,
	layout::Rect,
	text::{Line, Span},
	widgets::{Block, BorderType, Borders, Clear, Paragraph},
	Frame,
};
use scopeguard::defer;
use std::ffi::OsStr;
use std::{env, io, path::Path, process::Command};

///
pub struct ExternalEditorComponent {
	visible: bool,
	theme: SharedTheme,
	key_config: SharedKeyConfig,
}

impl ExternalEditorComponent {
	///
	pub fn new(
		theme: SharedTheme,
		key_config: SharedKeyConfig,
	) -> Self {
		Self {
			visible: false,
			theme,
			key_config,
		}
	}

	/// opens file at given `path` in an available editor
	pub fn open_file_in_editor(
		repo: &RepoPath,
		path: &Path,
	) -> Result<()> {
		let work_dir = repo_work_dir(repo)?;

		let path = if path.is_relative() {
			Path::new(&work_dir).join(path)
		} else {
			path.into()
		};

		if !path.exists() {
			bail!("file not found: {:?}", path);
		}

		io::stdout().execute(LeaveAlternateScreen)?;
		defer! {
			io::stdout().execute(EnterAlternateScreen).expect("reset terminal");
		}

		let environment_options = ["GIT_EDITOR", "VISUAL", "EDITOR"];

		let editor = env::var(environment_options[0])
			.ok()
			.or_else(|| {
				get_config_string(repo, "core.editor").ok()?
			})
			.or_else(|| env::var(environment_options[1]).ok())
			.or_else(|| env::var(environment_options[2]).ok())
			.unwrap_or_else(|| String::from("vi"));

		// TODO: proper handling arguments containing whitespaces
		// This does not do the right thing if the input is `editor --something "with spaces"`

		// deal with "editor name with spaces" p1 p2 p3
		// and with "editor_no_spaces" p1 p2 p3
		// does not address spaces in pn
		let mut echars = editor.chars().peekable();

		let first_char = *echars.peek().ok_or_else(|| {
			anyhow!(
				"editor env variable found empty: {}",
				environment_options.join(" or ")
			)
		})?;
		let command: String = if first_char == '\"' {
			echars
				.by_ref()
				.skip(1)
				.take_while(|c| *c != '\"')
				.collect()
		} else {
			echars.by_ref().take_while(|c| *c != ' ').collect()
		};

		let remainder_str = echars.collect::<String>();
		let remainder = remainder_str.split_whitespace();

		let mut args: Vec<&OsStr> =
			remainder.map(OsStr::new).collect();

		args.push(path.as_os_str());

		Command::new(command.clone())
			.current_dir(work_dir)
			.args(args)
			.status()
			.map_err(|e| anyhow!("\"{}\": {}", command, e))?;

		Ok(())
	}
}

impl DrawableComponent for ExternalEditorComponent {
	fn draw<B: Backend>(
		&self,
		f: &mut Frame<B>,
		_rect: Rect,
	) -> Result<()> {
		if self.visible {
			let txt = Line::from(
				strings::msg_opening_editor(&self.key_config)
					.split('\n')
					.map(|string| {
						Span::raw::<String>(string.to_string())
					})
					.collect::<Vec<Span>>(),
			);

			let area = ui::centered_rect_absolute(25, 3, f.size());
			f.render_widget(Clear, area);
			f.render_widget(
				Paragraph::new(txt)
					.block(
						Block::default()
							.borders(Borders::ALL)
							.border_type(BorderType::Thick)
							.border_style(self.theme.block(true)),
					)
					.style(self.theme.block(true)),
				area,
			);
		}

		Ok(())
	}
}

impl Component for ExternalEditorComponent {
	fn commands(
		&self,
		out: &mut Vec<CommandInfo>,
		force_all: bool,
	) -> CommandBlocking {
		if self.visible && !force_all {
			out.clear();
		}

		visibility_blocking(self)
	}

	fn event(&mut self, _ev: &Event) -> Result<EventState> {
		if self.visible {
			return Ok(EventState::Consumed);
		}

		Ok(EventState::NotConsumed)
	}

	fn is_visible(&self) -> bool {
		self.visible
	}

	fn hide(&mut self) {
		self.visible = false;
	}

	fn show(&mut self) -> Result<()> {
		self.visible = true;

		Ok(())
	}
}