//! Implementation of the `modderbaas install` subcommand.

use std::{io::Write, path::Path, str::FromStr};

use anyhow::{bail, Context, Result};
use clap::ArgMatches;
use itertools::Itertools;
use termcolor::StandardStream;

use modderbaas::{
    baas::{Baas, Installer},
    minemod::{self, ModContainer},
    util, ContentDb, Downloader, MineMod, Source, World,
};

use super::uiutil::{ask_continue, user_choice};

/// Install the given mods, installing dependencies if needed.
pub fn install_mods(
    output: &mut StandardStream,
    baas: &Baas,
    world: &World,
    mods: &[&str],
    matches: &ArgMatches,
) -> Result<()> {
    let target_dir = Path::new(matches.value_of("target").unwrap());
    let dry_run = matches.is_present("dry-run");
    let chown = matches.is_present("chown");

    let content_db = ContentDb::new();
    let downloader = Downloader::new()?;
    let sources = mods
        .iter()
        .map(|&s| Source::from_str(s))
        .collect::<Result<Vec<_>, _>>()?;

    let installer = InteractiveInstaller {
        output,
        content_db,
        target_dir,
        dry_run,
        chown,
    };
    baas.install(installer, &downloader, world, sources)?;

    writeln!(output, "Done!")?;

    Ok(())
}

/// The installer that interactively asks the user about choices.
struct InteractiveInstaller<'o, 'p> {
    output: &'o mut StandardStream,
    content_db: ContentDb,
    target_dir: &'p Path,
    dry_run: bool,
    chown: bool,
}

impl<'o, 'p> Installer for InteractiveInstaller<'o, 'p> {
    type Error = anyhow::Error;

    fn resolve(&mut self, mod_id: &str) -> Result<Source> {
        writeln!(&mut self.output, "Searching for candidates: {}", mod_id)?;

        let candidates = self.content_db.resolve(mod_id)?;
        if candidates.is_empty() {
            bail!("Could not find a suitable mod for '{}'", mod_id);
        } else if candidates.len() == 1 {
            Ok(Source::Http(candidates.into_iter().next().unwrap().url))
        } else {
            let items = candidates
                .into_iter()
                .map(|c| {
                    (
                        format!("{} by {} - {}", c.title, c.author, c.short_description),
                        c,
                    )
                })
                .collect::<Vec<_>>();
            writeln!(
                &mut self.output,
                "{} candidates found, please select one:",
                items.len()
            )?;
            let candidate = user_choice(&items, self.output)?;
            Ok(Source::Http(candidate.url.clone()))
        }
    }

    fn install_mod(&mut self, mod_or_pack: &dyn ModContainer) -> Result<Box<dyn ModContainer>> {
        let mod_id = mod_or_pack.name()?;
        writeln!(&mut self.output, "Installing {}", mod_id)?;

        if self.dry_run {
            // Re-open so we get a fresh Box<>
            return Ok(minemod::open_mod_or_pack(mod_or_pack.path())?);
        }

        let installed = mod_or_pack
            .install_to(self.target_dir)
            .context(format!("Error installing '{}'", mod_id))?;

        #[cfg(unix)]
        {
            use nix::{
                sys::stat,
                unistd::{Gid, Uid},
            };
            if self.chown {
                let perms = stat::stat(self.target_dir)?;
                let (uid, gid) = (Uid::from_raw(perms.st_uid), Gid::from_raw(perms.st_gid));
                util::chown_recursive(installed.path(), Some(uid), Some(gid))?;
            }
        }

        Ok(installed)
    }

    fn display_changes(&mut self, to_install: &[Box<dyn ModContainer>]) -> Result<()> {
        writeln!(
            &mut self.output,
            "Installing {} new mods:",
            to_install.len()
        )?;
        writeln!(&mut self.output, "{}", to_install.iter().join(", "))?;

        ask_continue(self.output)
    }

    fn enable_mod(&mut self, world: &World, minemod: &MineMod) -> Result<()> {
        let mod_id = minemod.mod_id()?;
        writeln!(&mut self.output, "Enabling {}", mod_id)?;

        if !self.dry_run {
            world
                .enable_mod(&mod_id)
                .context(format!("Error enabling '{}'", mod_id))?;
        }
        Ok(())
    }
}