#[macro_use]
extern crate rust_util;

use std::{env, fs, process};
use std::path::PathBuf;
use std::process::Command;
use std::time::SystemTime;

use rust_util::util_cmd;

fn main() {
    let user_home = get_user_home();
    let rust_script = get_run_script_bin_name(&user_home);

    let args = env::args().skip(1).collect::<Vec<_>>();
    if args.is_empty() {
        failure_and_exit!("runrs v{}, need arguments, e.g.\n\nrunrs <script.rs> [arguments]\n", env!("CARGO_PKG_VERSION"));
    }
    let first_argument = args.get(0).unwrap_or_else(|| failure_and_exit!("Must assign a script file name"));
    if first_argument == "--help" {
        print_help();
        return;
    }
    let script_file = first_argument;

    let (_, script_sha256) = read_file_and_digest(script_file);
    debugging!("File {} -> sha256: {}", script_file, script_sha256);

    let cache_script_bin_name = format!("{}/Library/Caches/rust-script/binaries/release/{}", user_home, script_sha256);
    let mut run_script_cmd = build_script_command(rust_script, script_file, &script_sha256, &cache_script_bin_name);
    for arg in args.iter().skip(1) {
        run_script_cmd.arg(arg);
    }
    run_script_command(script_file, &cache_script_bin_name, &mut run_script_cmd)
}

fn build_script_command(rust_script: PathBuf, script_file: &str, script_sha256: &str, cache_script_bin_name: &str) -> Command {
    let skip_cache = is_env_on("RUNRS_SKIP_CACHE");
    let cache_script_bin_name_exists = fs::metadata(&cache_script_bin_name).is_ok();
    debugging!("Bin name: {} {}exists", cache_script_bin_name, iff!(cache_script_bin_name_exists, "", "not "));
    if !skip_cache && cache_script_bin_name_exists {
        Command::new(&cache_script_bin_name)
    } else {
        let mut cmd = Command::new(rust_script);
        if !is_env_on("RUNRS_SILENT_BUILD") {
            cmd.arg("--cargo-output");
        }
        cmd.args(&["--bin-name", &script_sha256, script_file]);
        cmd
    }
}

fn run_script_command(script_file: &str, cache_script_bin_name: &str, mut run_script_cmd: &mut Command) -> ! {
    debugging!("Run command: {:?}", run_script_cmd);
    let run_command_start = SystemTime::now();
    match util_cmd::run_command_and_wait(&mut run_script_cmd) {
        Err(e) => failure_and_exit!("Run rust-script failed: {}", e),
        Ok(exit_status) => {
            write_script_file_to_src(script_file, cache_script_bin_name);
            if let Ok(run_command_cost) = SystemTime::now().duration_since(run_command_start) {
                debugging!("Run command cost: {}ms", run_command_cost.as_millis());
            }
            process::exit(exit_status.code().unwrap_or_else(|| 0))
        }
    }
}

fn write_script_file_to_src(script_file: &str, cache_script_bin_name: &str) {
    if let Ok(Some(canonicalized_script_file)) = PathBuf::from(script_file)
        .canonicalize().map(|f| f.to_str().map(|f| f.to_string())) {
        let cache_script_bin_name_src = format!("{}.src", cache_script_bin_name);
        let src_content = fs::read_to_string(&cache_script_bin_name_src).ok();
        if src_content.as_ref().map(|c| c.contains(&canonicalized_script_file)).unwrap_or_else(|| false) {
            return;
        }
        let new_src_content = src_content.unwrap_or_else(|| "".to_string()) + &format!("{}\n", canonicalized_script_file);
        if let Ok(_) = fs::write(&cache_script_bin_name_src, &new_src_content) {
            debugging!("Add {} to {}", canonicalized_script_file, cache_script_bin_name_src);
        }
    }
}

fn print_help() {
    println!(r##"{} v{} - {}

Help:
runrs --help

Run Rust Script:
runrs <script.rs> [arguments]
"##,
             env!("CARGO_PKG_NAME"),
             env!("CARGO_PKG_VERSION"),
             env!("CARGO_PKG_DESCRIPTION")
    );
}

fn read_file_and_digest(script_file: &str) -> (String, String) {
    let default_max_script_len = 1024 * 1024;
    let max_script_len: u64 = env::var("RUNRS_MAX_SCRIPT_LEN")
        .map(|len| len.parse().unwrap_or_else(|_| default_max_script_len)).unwrap_or_else(|_| default_max_script_len);
    match fs::metadata(script_file) {
        Err(_) => failure_and_exit!("Script file not exists: {}", script_file),
        Ok(metadata) => if metadata.is_dir() {
            failure_and_exit!("Assigned input is dir: {}", script_file);
        } else if metadata.len() > max_script_len {
            failure_and_exit!("Script file: {} too large: {}", script_file, metadata.len());
        }
    }
    let script_content = fs::read_to_string(script_file).unwrap_or_else(|e|
        failure_and_exit!("Read file: {}, failed: {}", script_file, e)
    );
    let script_sha256 = sha256::digest(&script_content);

    (script_content, script_sha256)
}

fn get_run_script_bin_name(home: &str) -> PathBuf {
    if let Ok(rust_script) = env::var("RUNRS_RUST_SCRIPT") {
        let rust_script_path_buf = PathBuf::from(&rust_script);
        if !rust_script_path_buf.exists() {
            warning!("RUST_SCRIPT={} not exists", &rust_script);
        }
        return rust_script_path_buf;
    }
    let rust_script = PathBuf::from(format!("{}/.cargo/bin/rust-script", home));
    if !rust_script.exists() {
        warning!("rust-script not found, install it...");
        let mut cargo_install_rust_script = Command::new("cargo");
        cargo_install_rust_script.args(&["install", "--git", "https://git.hatter.ink/hatter/runrs", "rust-script"]);
        debugging!("Run command: {:?}", cargo_install_rust_script);
        match util_cmd::run_command_and_wait(&mut cargo_install_rust_script) {
            Err(e) => failure_and_exit!("Install rust-script failed: {}", e),
            Ok(exist_status) => if !exist_status.success() {
                failure!("Install rust-script not success: {}", exist_status);
            },
        }
    }
    rust_script
}

fn is_env_on(env: &str) -> bool {
    env::var(env).map(|v| {
        let v = v.to_lowercase();
        v == "true" || v == "on" || v == "yes" || v == "1"
    }).unwrap_or_else(|_| false)
}

fn get_user_home() -> String {
    env::var("HOME").unwrap_or_else(|_|
        failure_and_exit!("$HOME not found!")
    )
}