use std::{fmt::Write as _, process::ExitCode};

use anyhow::{Context, Result};
use clap::{CommandFactory, Parser};

use lune::Lune;
use tokio::{
    fs::read as read_to_vec,
    io::{stdin, AsyncReadExt},
};

pub(crate) mod gen;
pub(crate) mod repl;
pub(crate) mod setup;
pub(crate) mod utils;

use setup::run_setup;
use utils::{
    files::{discover_script_path_including_lune_dirs, strip_shebang},
    listing::{find_lune_scripts, sort_lune_scripts, write_lune_scripts_list},
};

/// A Luau script runner
#[derive(Parser, Debug, Default, Clone)]
#[command(version, long_about = None)]
#[allow(clippy::struct_excessive_bools)]
pub struct Cli {
    /// Script name or full path to the file to run
    script_path: Option<String>,
    /// Arguments to pass to the script, stored in process.args
    script_args: Vec<String>,
    /// List scripts found inside of a nearby `lune` directory
    #[clap(long, short = 'l')]
    list: bool,
    /// Set up type definitions and settings for development
    #[clap(long)]
    setup: bool,
    /// Generate a Luau type definitions file in the current dir
    #[clap(long, hide = true)]
    generate_luau_types: bool,
    /// Generate a Selene type definitions file in the current dir
    #[clap(long, hide = true)]
    generate_selene_types: bool,
    /// Generate a Lune documentation file for Luau LSP
    #[clap(long, hide = true)]
    generate_docs_file: bool,
}

#[allow(dead_code)]
impl Cli {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn with_path<S>(mut self, path: S) -> Self
    where
        S: Into<String>,
    {
        self.script_path = Some(path.into());
        self
    }

    pub fn with_args<A>(mut self, args: A) -> Self
    where
        A: Into<Vec<String>>,
    {
        self.script_args = args.into();
        self
    }

    pub fn setup(mut self) -> Self {
        self.setup = true;
        self
    }

    pub fn list(mut self) -> Self {
        self.list = true;
        self
    }

    #[allow(clippy::too_many_lines)]
    pub async fn run(self) -> Result<ExitCode> {
        // List files in `lune` and `.lune` directories, if wanted
        // This will also exit early and not run anything else
        if self.list {
            let sorted_relative = match find_lune_scripts(false).await {
                Ok(scripts) => sort_lune_scripts(scripts),
                Err(e) => {
                    eprintln!("{e}");
                    return Ok(ExitCode::FAILURE);
                }
            };
            let sorted_home_dir = match find_lune_scripts(true).await {
                Ok(scripts) => sort_lune_scripts(scripts),
                Err(e) => {
                    eprintln!("{e}");
                    return Ok(ExitCode::FAILURE);
                }
            };

            let mut buffer = String::new();
            if !sorted_relative.is_empty() {
                if sorted_home_dir.is_empty() {
                    write!(&mut buffer, "Available scripts:")?;
                } else {
                    write!(&mut buffer, "Available scripts in current directory:")?;
                }
                write_lune_scripts_list(&mut buffer, sorted_relative)?;
            }
            if !sorted_home_dir.is_empty() {
                write!(&mut buffer, "Available global scripts:")?;
                write_lune_scripts_list(&mut buffer, sorted_home_dir)?;
            }

            if buffer.is_empty() {
                println!("No scripts found.");
            } else {
                print!("{buffer}");
            }

            return Ok(ExitCode::SUCCESS);
        }
        // Generate (save) definition files, if wanted
        let generate_file_requested = self.setup
            || self.generate_luau_types
            || self.generate_selene_types
            || self.generate_docs_file;
        if generate_file_requested {
            if (self.generate_luau_types || self.generate_selene_types || self.generate_docs_file)
                && !self.setup
            {
                eprintln!(
                    "\
					Typedef & docs generation commands have been superseded by the setup command.\
					Run `lune --setup` in your terminal to configure your editor and type definitions.
					"
                );
                return Ok(ExitCode::FAILURE);
            }
            if self.setup {
                run_setup().await;
            }
        }
        if self.script_path.is_none() {
            // Only generating typedefs without running a script is completely
            // fine, and we should just exit the program normally afterwards
            if generate_file_requested {
                return Ok(ExitCode::SUCCESS);
            }

            // HACK: We know that we didn't get any arguments here but since
            // script_path is optional clap will not error on its own, to fix
            // we will duplicate the CLI command and fetch the version of
            // lune to display
            let exit_code_status = repl::show_interface(Cli::command()).await;

            return exit_code_status;
        }
        // Figure out if we should read from stdin or from a file,
        // reading from stdin is marked by passing a single "-"
        // (dash) as the script name to run to the cli
        let script_path = self.script_path.unwrap();
        let (script_display_name, script_contents) = if script_path == "-" {
            let mut stdin_contents = Vec::new();
            stdin()
                .read_to_end(&mut stdin_contents)
                .await
                .context("Failed to read script contents from stdin")?;
            ("stdin".to_string(), stdin_contents)
        } else {
            let file_path = discover_script_path_including_lune_dirs(&script_path)?;
            let file_contents = read_to_vec(&file_path).await?;
            // NOTE: We skip the extension here to remove it from stack traces
            let file_display_name = file_path.with_extension("").display().to_string();
            (file_display_name, file_contents)
        };
        // Create a new lune object with all globals & run the script
        let result = Lune::new()
            .with_args(self.script_args)
            .run(&script_display_name, strip_shebang(script_contents))
            .await;
        Ok(match result {
            Err(err) => {
                eprintln!("{err}");
                ExitCode::FAILURE
            }
            Ok(code) => code,
        })
    }
}