use std::{
    io::{self, Write},
    net::{IpAddr, Ipv4Addr},
    path::PathBuf,
    sync::Arc,
};

use clap::Parser;
use memofs::Vfs;
use termcolor::{BufferWriter, Color, ColorChoice, ColorSpec, WriteColor};

use crate::{serve_session::ServeSession, web::LiveServer};

use super::{resolve_path, GlobalOptions};

const DEFAULT_BIND_ADDRESS: Ipv4Addr = Ipv4Addr::new(127, 0, 0, 1);
const DEFAULT_PORT: u16 = 34872;

/// Expose a Rojo project to the Rojo Studio plugin.
#[derive(Debug, Parser)]
pub struct ServeCommand {
    /// Path to the project to serve. Defaults to the current directory.
    #[clap(default_value = "")]
    pub project: PathBuf,

    /// The IP address to listen on. Defaults to `127.0.0.1`.
    #[clap(long)]
    pub address: Option<IpAddr>,

    /// The port to listen on. Defaults to the project's preference, or `34872` if
    /// it has none.
    #[clap(long)]
    pub port: Option<u16>,

    /// Extra `Host`/`Origin` values the server will accept, beyond localhost and
    /// the bind address (for example a hostname like `mypc.lan`). Repeat the
    /// option or comma-separate to allow several. When given, this overrides the
    /// project's `serveAllowedHosts`. Listing any host also turns on Host/Origin
    /// validation for binds where it is otherwise off (such as `0.0.0.0`).
    #[clap(long, value_delimiter = ',')]
    pub allowed_hosts: Vec<String>,
}

impl ServeCommand {
    pub fn run(self, global: GlobalOptions) -> anyhow::Result<()> {
        let project_path = resolve_path(&self.project)?;

        let vfs = Vfs::new_default()?;

        let session = Arc::new(ServeSession::new(vfs, project_path)?);

        let ip = self
            .address
            .or_else(|| session.serve_address())
            .unwrap_or(DEFAULT_BIND_ADDRESS.into());

        let port = self
            .port
            .or_else(|| session.project_port())
            .unwrap_or(DEFAULT_PORT);

        // The CLI flag, when given, replaces the project's list rather than
        // merging with it, matching how --address and --port override theirs.
        let allowed_hosts = if self.allowed_hosts.is_empty() {
            session.serve_allowed_hosts().to_vec()
        } else {
            self.allowed_hosts
        };

        let server = LiveServer::new(session);

        server.start((ip, port).into(), allowed_hosts, || {
            let _ = show_start_message(ip, port, global.color.into());
        })?;

        Ok(())
    }
}

fn show_start_message(bind_address: IpAddr, port: u16, color: ColorChoice) -> io::Result<()> {
    let mut green = ColorSpec::new();
    green.set_fg(Some(Color::Green)).set_bold(true);

    let writer = BufferWriter::stdout(color);
    let mut buffer = writer.buffer();

    let address_string = if bind_address.is_loopback() {
        "localhost".to_owned()
    } else {
        bind_address.to_string()
    };

    writeln!(&mut buffer, "Rojo server listening:")?;

    write!(&mut buffer, "  Address: ")?;
    buffer.set_color(&green)?;
    writeln!(&mut buffer, "{}", address_string)?;

    buffer.set_color(&ColorSpec::new())?;
    write!(&mut buffer, "  Port:    ")?;
    buffer.set_color(&green)?;
    writeln!(&mut buffer, "{}", port)?;

    writeln!(&mut buffer)?;

    if !bind_address.is_loopback() {
        let mut warning = ColorSpec::new();
        warning.set_fg(Some(Color::Yellow)).set_bold(true);

        buffer.set_color(&warning)?;
        writeln!(
            &mut buffer,
            "WARNING: This server is bound to {address_string}, which is reachable from the \
             network.\n\
             The serve API is unauthenticated, so anyone who can reach {address_string}:{port} \
             can read\n\
             and modify your project's source. Prefer binding to localhost and tunneling (e.g. \
             SSH,\n\
             Tailscale, or WireGuard) when you need remote access."
        )?;
        buffer.set_color(&ColorSpec::new())?;
        writeln!(&mut buffer)?;
    }

    buffer.set_color(&ColorSpec::new())?;
    write!(&mut buffer, "Visit ")?;

    buffer.set_color(&green)?;
    write!(&mut buffer, "http://{}:{}/", address_string, port)?;

    buffer.set_color(&ColorSpec::new())?;
    writeln!(&mut buffer, " in your browser for more information.")?;

    writer.print(&buffer)?;

    Ok(())
}