use std::io::stderr;
use std::process::{exit, Stdio};
use std::time::{Duration, Instant};

use colored::Colorize;
use regex_lite::Regex;

use crate::files::{get_best_match_file, get_path_files};
use crate::rules::match_pattern;
use crate::shell::{expand_alias_multiline, shell_evaluated_commands, PRIVILEGE_LIST};

pub fn suggest_command(shell: &str, last_command: &str, error_msg: &str) -> Option<String> {
	let split_command = split_command(last_command);
	let executable = match PRIVILEGE_LIST.contains(&split_command[0].as_str()) {
		true => split_command.get(1).expect(&t!("no-command")).as_str(),
		false => split_command.first().expect(&t!("no-command")).as_str(),
	};

	if !PRIVILEGE_LIST.contains(&executable) {
		let suggest = match_pattern("_PR_privilege", last_command, error_msg, shell);
		if suggest.is_some() {
			return suggest;
		}
	}

	let last_command = match PRIVILEGE_LIST.contains(&split_command[0].as_str()) {
		true => &last_command[split_command[0].len() + 1..],
		false => last_command,
	};

	let suggest = match_pattern(executable, last_command, error_msg, shell);
	if let Some(suggest) = suggest {
		if PRIVILEGE_LIST.contains(&split_command[0].as_str()) {
			return Some(format!("{} {}", split_command[0], suggest));
		}
		return Some(suggest);
	}

	let suggest = match_pattern("_PR_general", last_command, error_msg, shell);
	if let Some(suggest) = suggest {
		if PRIVILEGE_LIST.contains(&split_command[0].as_str()) {
			return Some(format!("{} {}", split_command[0], suggest));
		}
		return Some(suggest);
	}

	#[cfg(feature = "runtime-rules")]
	{
		use crate::runtime_rules::runtime_match;
		let suggest = runtime_match(executable, last_command, error_msg, shell);
		if let Some(suggest) = suggest {
			if PRIVILEGE_LIST.contains(&split_command[0].as_str()) {
				return Some(format!("{} {}", split_command[0], suggest));
			}
			return Some(suggest);
		}
	}

	#[cfg(feature = "request-ai")]{
		use crate::requests::ai_suggestion;
		let suggest = ai_suggestion(last_command, error_msg);
		if let Some(suggest) = suggest {
			eprintln!("{}: {}\n", t!("ai-suggestion").bold().blue(), suggest.note);
			let command = suggest.command;
			if command != "None" {
				if PRIVILEGE_LIST.contains(&split_command[0].as_str()) {
					return Some(format!("{} {}", split_command[0], command));
				}
				return Some(command);
			}
		}
	}

	None
}

pub fn check_executable(shell: &str, executable: &str) -> bool {
	match shell {
		"nu" => std::process::Command::new(shell)
			.arg("-c")
			.arg(format!("if (which {} | is-empty) {{ exit 1 }}", executable))
			.output()
			.expect("failed to execute process")
			.status
			.success(),
		_ => std::process::Command::new(shell)
			.arg("-c")
			.arg(format!("command -v {}", executable))
			.output()
			.expect("failed to execute process")
			.status
			.success(),
	}
}

pub fn opt_regex(regex: &str, command: &mut String) -> String {
	let regex = Regex::new(regex).unwrap();

	let mut opts = Vec::new();
	for captures in regex.captures_iter(command) {
		for cap in captures.iter().skip(1).flatten() {
			opts.push(cap.as_str().to_owned());
		}
	}

	for opt in opts.clone() {
		*command = command.replace(&opt, "");
	}
	opts.join(" ")
}

pub fn err_regex(regex: &str, error_msg: &str) -> String {
	let regex = Regex::new(regex).unwrap();

	let mut err = Vec::new();
	for captures in regex.captures_iter(error_msg) {
		for cap in captures.iter().skip(1).flatten() {
			err.push(cap.as_str().to_owned());
		}
	}
	err.join(" ")
}

pub fn cmd_regex(regex: &str, command: &str) -> String {
	let regex = Regex::new(regex).unwrap();

	let mut cmd = Vec::new();
	for captures in regex.captures_iter(command) {
		for cap in captures.iter().skip(1).flatten() {
			cmd.push(cap.as_str().to_owned());
		}
	}
	cmd.join(" ")
}

pub fn eval_shell_command(shell: &str, command: &str) -> Vec<String> {
	let output = std::process::Command::new(shell)
		.arg("-c")
		.arg(command)
		.output()
		.expect("failed to execute process");
	let output = String::from_utf8_lossy(&output.stdout);
	let split_output = output.split('\n').collect::<Vec<&str>>();
	split_output
		.iter()
		.map(|s| s.trim().to_string())
		.collect::<Vec<String>>()
}

pub fn split_command(command: &str) -> Vec<String> {
	// this regex splits the command separated by spaces, except when the space
	// is escaped by a backslash or surrounded by quotes
	let regex = r#"([^\s"'\\]+|"(?:\\.|[^"\\])*"|'(?:\\.|[^'\\])*'|\\ )+|\\|\n"#;
	let regex = Regex::new(regex).unwrap();
	let split_command = regex
		.find_iter(command)
		.map(|cap| cap.as_str().to_owned())
		.collect::<Vec<String>>();
	split_command
}

pub fn suggest_typo(typos: &[String], candidates: Vec<String>) -> String {
	let mut path_files = Vec::new();
	let mut suggestions = Vec::new();
	for typo in typos {
		let typo = typo.as_str();
		if candidates.len() == 1 {
			match candidates[0].as_str() {
				"path" => {
					if path_files.is_empty() {
						path_files = get_path_files();
					};
					if let Some(suggest) = find_similar(typo, &path_files) {
						suggestions.push(suggest);
					};
				}
				"file" => {
					if let Some(suggest) = get_best_match_file(typo) {
						suggestions.push(suggest);
					}
				}
				_ => {}
			}
		} else if let Some(suggest) = find_similar(typo, &candidates) {
			suggestions.push(suggest);
		}
	}
	suggestions.join(" ")
}

pub fn find_similar(typo: &str, candidates: &[String]) -> Option<String> {
	let mut min_distance = 10;
	let mut min_distance_index = None;
	for (i, candidate) in candidates.iter().enumerate() {
		if candidate.is_empty() {
			continue;
		}
		let distance = compare_string(typo, candidate);
		if distance < min_distance {
			min_distance = distance;
			min_distance_index = Some(i);
		}
	}
	if let Some(min_distance_index) = min_distance_index {
		return Some(candidates[min_distance_index].to_string());
	}
	None
}

#[allow(clippy::needless_range_loop)]
pub fn compare_string(a: &str, b: &str) -> usize {
	let mut matrix = vec![vec![0; b.chars().count() + 1]; a.chars().count() + 1];

	for i in 0..a.chars().count() + 1 {
		matrix[i][0] = i;
	}
	for j in 0..b.chars().count() + 1 {
		matrix[0][j] = j;
	}

	for (i, ca) in a.chars().enumerate() {
		for (j, cb) in b.chars().enumerate() {
			let cost = if ca == cb { 0 } else { 1 };
			matrix[i + 1][j + 1] = std::cmp::min(
				std::cmp::min(matrix[i][j + 1] + 1, matrix[i + 1][j] + 1),
				matrix[i][j] + cost,
			);
		}
	}
	matrix[a.chars().count()][b.chars().count()]
}

pub fn confirm_suggestion(shell: &str, command: &str, highlighted: &str) -> Result<(), String> {
	eprintln!("{}\n", highlighted);
	let confirm = format!("[{}]", t!("confirm-yes")).green();
	eprintln!("{}: {} {}", t!("confirm"), confirm, "[Ctrl+C]".red());
	std::io::stdin().read_line(&mut String::new()).unwrap();

	for p in PRIVILEGE_LIST {
		let _p = p.to_owned() + " ";
		if !command.starts_with(&_p) {
			continue;
		}
		let mut command = command.replacen(&_p, "", 1);
		command = expand_alias_multiline(shell, &command);

		let now = Instant::now();
		let process = run_suggestion_p(shell, p, &command);

		if process.success() {
			let cd = shell_evaluated_commands(shell, &command);
			if let Some(cd) = cd {
				println!("{}", cd);
			}
		} else {
			if now.elapsed() > Duration::from_secs(3) {
				exit(1);
			}
			let process = std::process::Command::new(p)
				.arg(shell)
				.arg("-c")
				.arg(command)
				.env("LC_ALL", "C")
				.output()
				.expect("failed to execute process");
			let error_msg = match process.stderr.is_empty() {
				true => String::from_utf8_lossy(&process.stdout),
				false => String::from_utf8_lossy(&process.stderr),
			};
			return Err(error_msg.to_string());
		}
	}

	let command = expand_alias_multiline(shell, command);
	let now = Instant::now();
	let process = run_suggestion(shell, &command);

	if process.success() {
		let cd = shell_evaluated_commands(shell, &command);
		if let Some(cd) = cd {
			println!("{}", cd);
		}
		Ok(())
	} else {
		if now.elapsed() > Duration::from_secs(3) {
			exit(1);
		}
		let process = std::process::Command::new(shell)
			.arg("-c")
			.arg(command)
			.env("LC_ALL", "C")
			.output()
			.expect("failed to execute process");
		let error_msg = match process.stderr.is_empty() {
			true => String::from_utf8_lossy(&process.stdout).to_lowercase(),
			false => String::from_utf8_lossy(&process.stderr).to_lowercase(),
		};
		Err(error_msg.to_string())
	}
}

#[cfg(not(target_os = "windows"))]
fn run_suggestion_p(shell: &str, p: &str, command: &str) -> std::process::ExitStatus {
	use std::os::fd::AsFd;
	std::process::Command::new(p)
		.arg(shell)
		.arg("-c")
		.arg(command)
		.stdout(stderr().as_fd().try_clone_to_owned().unwrap())
		.stderr(Stdio::inherit())
		.spawn()
		.expect("failed to execute process")
		.wait()
		.unwrap()
}

#[cfg(not(target_os = "windows"))]
fn run_suggestion(shell: &str, command: &str) -> std::process::ExitStatus {
	use std::os::fd::AsFd;
	std::process::Command::new(shell)
		.arg("-c")
		.arg(command)
		// .stdout(Stdio::inherit())
		.stdout(stderr().as_fd().try_clone_to_owned().unwrap())
		.stderr(Stdio::inherit())
		.spawn()
		.expect("failed to execute process")
		.wait()
		.unwrap()
}

#[cfg(target_os = "windows")]
fn run_suggestion_p(shell: &str, p: &str, command: &str) -> std::process::ExitStatus {
	use std::os::windows::io::AsHandle;
	std::process::Command::new(p)
		.arg(shell)
		.arg("-c")
		.arg(command)
		.stdout(stderr().as_handle().try_clone_to_owned().unwrap())
		.stderr(Stdio::inherit())
		.spawn()
		.expect("failed to execute process")
		.wait()
		.unwrap()
}

#[cfg(target_os = "windows")]
fn run_suggestion(shell: &str, command: &str) -> std::process::ExitStatus {
	use std::os::windows::io::AsHandle;
	std::process::Command::new(shell)
		.arg("-c")
		.arg(command)
		.stdout(stderr().as_handle().try_clone_to_owned().unwrap())
		.stderr(Stdio::inherit())
		.spawn()
		.expect("failed to execute process")
		.wait()
		.unwrap()
}