use std::path::{Path, PathBuf};
use std::process::{exit, Command, Stdio};

use structopt::StructOpt;
use toml::Value;

use log::{error, info, warn};

#[derive(StructOpt, Debug)]
#[structopt(name = "cargo-remote", bin_name = "cargo")]
enum Opts {
    #[structopt(name = "remote")]
    Remote {
        #[structopt(short = "r", long = "remote", help = "remote ssh build server")]
        remote: Option<String>,

        #[structopt(
            short = "c",
            long = "copy-back",
            help = "transfer the target folder back to the local machine"
        )]
        copy_back: bool,

        #[structopt(
            long = "manifest-path",
            help = "Path to the manifest to execute",
            default_value = "Cargo.toml",
            parse(from_os_str)
        )]
        manifest_path: PathBuf,

        #[structopt(
            short = "h",
            long = "transfer-hidden",
            help = "transfer hidden files and directories to the build server"
        )]
        hidden: bool,

        #[structopt(help = "cargo command that will be executed remotely")]
        command: String,

        #[structopt(
            help = "cargo options and flags that will be applied remotely",
            name = "remote options"
        )]
        options: Vec<String>,
    },
}

/// Tries to parse the file [`config_path`]. Logs warnings and returns [`None`] if errors occur
/// during reading or parsing, [`Some(Value)`] otherwise.
fn config_from_file(config_path: &Path) -> Option<Value> {
    let config_file = std::fs::read_to_string(config_path)
        .map_err(|e| {
            warn!(
                "Can't parse config file '{}' (error: {})",
                config_path.to_string_lossy(),
                e
            );
        })
        .ok()?;

    let value = config_file
        .parse::<Value>()
        .map_err(|e| {
            warn!(
                "Can't parse config file '{}' (error: {})",
                config_path.to_string_lossy(),
                e
            );
        })
        .ok()?;

    Some(value)
}

fn main() {
    simple_logger::init().unwrap();

    let Opts::Remote {
        remote,
        copy_back,
        manifest_path,
        hidden,
        command,
        options,
    } = Opts::from_args();

    let mut metadata_cmd = cargo_metadata::MetadataCommand::new();
    metadata_cmd.manifest_path(manifest_path).no_deps();

    let project_metadata = metadata_cmd.exec().unwrap();

    // for now, assume that there is only one project and find it's root directory
    let (project_dir, project_name) = project_metadata.packages.first().map_or_else(
        || {
            error!("No project found.");
            exit(-2);
        },
        |project| (&project_metadata.workspace_root, &project.name),
    );

    let configs = vec![
        config_from_file(&project_dir.join(".cargo-remote.toml")),
        xdg::BaseDirectories::with_prefix("cargo-remote")
            .ok()
            .and_then(|base| base.find_config_file("cargo-remote.toml"))
            .and_then(|p: PathBuf| config_from_file(&p)),
    ];

    // TODO: move Opts::Remote fields into own type and implement complete_from_config(&mut self, config: &Value)
    let build_server = remote
        .or_else(|| {
            configs
                .into_iter()
                .flat_map(|config| config.and_then(|c| c["remote"].as_str().map(String::from)))
                .next()
        })
        .unwrap_or_else(|| {
            error!("No remote build server was defined (use config file or --remote flag)");
            exit(-3);
        });

    let build_path = format!("~/remote-builds/{}/", project_name);

    info!("Transferring sources to build server.");
    // transfer project to build server
    let mut rsync_to = Command::new("rsync");
    rsync_to
        .arg("-a".to_owned())
        .arg("--delete")
        .arg("--info=progress2")
        .arg("--exclude")
        .arg("target");

    if !hidden {
        rsync_to.arg("--exclude").arg(".*");
    }

    rsync_to
        .arg("--rsync-path")
        .arg("mkdir -p remote-builds && rsync")
        .arg(format!("{}/", project_dir.to_string_lossy()))
        .arg(format!("{}:{}", build_server, build_path))
        .stdout(Stdio::inherit())
        .stderr(Stdio::inherit())
        .stdin(Stdio::inherit())
        .output()
        .unwrap_or_else(|e| {
            error!("Failed to transfer project to build server (error: {})", e);
            exit(-4);
        });

    let build_command = format!(
        "cd {}; $HOME/.cargo/bin/cargo {} {}",
        build_path,
        command,
        options.join(" ")
    );

    info!("Starting build process.");
    Command::new("ssh")
        .arg("-t")
        .arg(&build_server)
        .arg(build_command)
        .stdout(Stdio::inherit())
        .stderr(Stdio::inherit())
        .stdin(Stdio::inherit())
        .output()
        .unwrap_or_else(|e| {
            error!("Failed to run cargo command remotely (error: {})", e);
            exit(-5);
        });

    if copy_back {
        info!("Transferring artifacts back to client.");
        Command::new("rsync")
            .arg("-a")
            .arg("--delete")
            .arg("--compress")
            .arg("--info=progress2")
            .arg(format!("{}:{}/target/", build_server, build_path))
            .arg(format!("{}/target/", project_dir.to_string_lossy()))
            .stdout(Stdio::inherit())
            .stderr(Stdio::inherit())
            .stdin(Stdio::inherit())
            .output()
            .unwrap_or_else(|e| {
                error!(
                    "Failed to transfer target back to local machine (error: {})",
                    e
                );
                exit(-6);
            });
    }
}