extern crate bytesize;
extern crate downcast_rs;
extern crate serde;
extern crate serde_derive;

#[cfg(target_os = "windows")]
extern crate static_vcruntime;

use bytesize::ByteSize;
use chrono::{DateTime, Datelike, Local, TimeZone};
use evtx::{EvtxParser, ParserSettings};
use git2::Repository;
use hashbrown::{HashMap, HashSet};
use hayabusa::detections::configs::{load_pivot_keywords, TargetEventTime, TARGET_EXTENSIONS};
use hayabusa::detections::detection::{self, EvtxRecordInfo};
use hayabusa::detections::pivot::PivotKeyword;
use hayabusa::detections::pivot::PIVOT_KEYWORD;
use hayabusa::detections::print::{
    AlertMessage, ERROR_LOG_PATH, ERROR_LOG_STACK, LOGONSUMMARY_FLAG, PIVOT_KEYWORD_LIST_FLAG,
    QUIET_ERRORS_FLAG, STATISTICS_FLAG,
};
use hayabusa::detections::rule::{get_detection_keys, RuleNode};
use hayabusa::omikuji::Omikuji;
use hayabusa::options::level_tuning::LevelTuning;
use hayabusa::yaml::ParseYaml;
use hayabusa::{afterfact::after_fact, detections::utils};
use hayabusa::{detections::configs, timeline::timelines::Timeline};
use hayabusa::{detections::utils::write_color_buffer, filter};
use hhmmss::Hhmmss;
use pbr::ProgressBar;
use serde_json::Value;
use std::cmp::Ordering;
use std::ffi::{OsStr, OsString};
use std::fmt::Display;
use std::fmt::Write as _;
use std::fs::create_dir;
use std::io::{BufWriter, Write};
use std::path::Path;
use std::sync::Arc;
use std::time::SystemTime;
use std::{
    env,
    fs::{self, File},
    path::PathBuf,
    vec,
};
use termcolor::{BufferWriter, Color, ColorChoice};
use tokio::runtime::Runtime;
use tokio::spawn;
use tokio::task::JoinHandle;

#[cfg(target_os = "windows")]
use is_elevated::is_elevated;

// 一度にtimelineやdetectionを実行する行数
const MAX_DETECT_RECORDS: usize = 5000;

fn main() {
    let mut app = App::new();
    app.exec();
    app.rt.shutdown_background();
}

pub struct App {
    rt: Runtime,
    rule_keys: Vec<String>,
}

impl Default for App {
    fn default() -> Self {
        Self::new()
    }
}

impl App {
    pub fn new() -> App {
        App {
            rt: utils::create_tokio_runtime(),
            rule_keys: Vec::new(),
        }
    }

    fn exec(&mut self) {
        if *PIVOT_KEYWORD_LIST_FLAG {
            load_pivot_keywords("config/pivot_keywords.txt");
        }

        let analysis_start_time: DateTime<Local> = Local::now();
        // Show usage when no arguments.
        if std::env::args().len() == 1 {
            self.output_logo();
            configs::CONFIG.write().unwrap().app.print_help().ok();
            println!();
            return;
        }
        if !configs::CONFIG.read().unwrap().args.quiet {
            self.output_logo();
            println!();
            self.output_eggs(&format!(
                "{:02}/{:02}",
                &analysis_start_time.month().to_owned(),
                &analysis_start_time.day().to_owned()
            ));
        }

        if !self.is_matched_architecture_and_binary() {
            AlertMessage::alert(
                "The hayabusa version you ran does not match your PC architecture.\nPlease use the correct architecture. (Binary ending in -x64.exe for 64-bit and -x86.exe for 32-bit.)",
            )
            .ok();
            println!();
            return;
        }

        if configs::CONFIG.read().unwrap().args.update_rules {
            match self.update_rules() {
                Ok(output) => {
                    if output != "You currently have the latest rules." {
                        write_color_buffer(
                            BufferWriter::stdout(ColorChoice::Always),
                            None,
                            "Rules updated successfully.",
                        )
                        .ok();
                    }
                }
                Err(e) => {
                    AlertMessage::alert(&format!("Failed to update rules. {:?}  ", e)).ok();
                }
            }
            println!();
            return;
        }

        if !Path::new("./config").exists() {
            AlertMessage::alert(
                "Hayabusa could not find the config directory.\nPlease run it from the Hayabusa root directory.\nExample: ./hayabusa-1.0.0-windows-x64.exe"
            )
            .ok();
            return;
        }

        if let Some(csv_path) = &configs::CONFIG.read().unwrap().args.output {
            let pivot_key_unions = PIVOT_KEYWORD.read().unwrap();
            pivot_key_unions.iter().for_each(|(key, _)| {
                let keywords_file_name =
                    csv_path.as_path().display().to_string() + "-" + key + ".txt";
                if Path::new(&keywords_file_name).exists() {
                    AlertMessage::alert(&format!(
                        " The file {} already exists. Please specify a different filename.",
                        &keywords_file_name
                    ))
                    .ok();
                }
            });
            if csv_path.exists() {
                AlertMessage::alert(&format!(
                    " The file {} already exists. Please specify a different filename.",
                    csv_path.as_os_str().to_str().unwrap()
                ))
                .ok();
                return;
            }
        }

        let time_filter = TargetEventTime::default();
        if !time_filter.is_parse_success() {
            return;
        }

        if *STATISTICS_FLAG {
            write_color_buffer(
                BufferWriter::stdout(ColorChoice::Always),
                None,
                "Generating Event ID Statistics",
            )
            .ok();
            println!();
        }
        if *LOGONSUMMARY_FLAG {
            write_color_buffer(
                BufferWriter::stdout(ColorChoice::Always),
                None,
                "Generating Logons Summary",
            )
            .ok();
            println!();
        }

        if configs::CONFIG.read().unwrap().args.live_analysis {
            let live_analysis_list = self.collect_liveanalysis_files();
            if live_analysis_list.is_none() {
                return;
            }
            self.analysis_files(live_analysis_list.unwrap(), &time_filter);
        } else if let Some(filepath) = &configs::CONFIG.read().unwrap().args.filepath {
            if !TARGET_EXTENSIONS.contains(
                filepath
                    .extension()
                    .unwrap_or_else(|| OsStr::new("."))
                    .to_str()
                    .unwrap(),
            ) || filepath
                .as_path()
                .file_stem()
                .unwrap_or_else(|| OsStr::new("."))
                .to_str()
                .unwrap()
                .trim()
                .starts_with('.')
            {
                AlertMessage::alert(
                    "--filepath only accepts .evtx files. Hidden files are ignored.",
                )
                .ok();
                return;
            }
            self.analysis_files(vec![PathBuf::from(filepath)], &time_filter);
        } else if let Some(directory) = &configs::CONFIG.read().unwrap().args.directory {
            let evtx_files = self.collect_evtxfiles(directory.as_os_str().to_str().unwrap());
            if evtx_files.is_empty() {
                AlertMessage::alert("No .evtx files were found.").ok();
                return;
            }
            self.analysis_files(evtx_files, &time_filter);
        } else if configs::CONFIG.read().unwrap().args.contributors {
            self.print_contributors();
            return;
        } else if std::env::args()
            .into_iter()
            .any(|arg| arg.contains("level-tuning"))
        {
            let level_tuning_config_path = configs::CONFIG
                .read()
                .unwrap()
                .args
                .level_tuning
                .as_path()
                .display()
                .to_string();

            if Path::new(&level_tuning_config_path).exists() {
                if let Err(err) = LevelTuning::run(
                    &level_tuning_config_path,
                    configs::CONFIG
                        .read()
                        .unwrap()
                        .args
                        .rules
                        .as_os_str()
                        .to_str()
                        .unwrap(),
                ) {
                    AlertMessage::alert(&err).ok();
                }
            } else {
                AlertMessage::alert(
                    "Need rule_levels.txt file to use --level-tuning option [default: ./rules/config/level_tuning.txt]",
                )
                .ok();
            }
            return;
        } else {
            write_color_buffer(
                BufferWriter::stdout(ColorChoice::Always),
                None,
                &configs::CONFIG.read().unwrap().headless_help,
            )
            .ok();
            return;
        }

        let analysis_end_time: DateTime<Local> = Local::now();
        let analysis_duration = analysis_end_time.signed_duration_since(analysis_start_time);
        println!();
        write_color_buffer(
            BufferWriter::stdout(ColorChoice::Always),
            None,
            &format!("Elapsed Time: {}", &analysis_duration.hhmmssxxx()),
        )
        .ok();
        println!();

        // Qオプションを付けた場合もしくはパースのエラーがない場合はerrorのstackが0となるのでエラーログファイル自体が生成されない。
        if ERROR_LOG_STACK.lock().unwrap().len() > 0 {
            AlertMessage::create_error_log(ERROR_LOG_PATH.to_string());
        }

        if *PIVOT_KEYWORD_LIST_FLAG {
            let pivot_key_unions = PIVOT_KEYWORD.read().unwrap();
            let create_output = |mut output: String, key: &String, pivot_keyword: &PivotKeyword| {
                write!(output, "{}: ", key).ok();

                write!(output, "( ").ok();
                for i in pivot_keyword.fields.iter() {
                    write!(output, "%{}% ", i).ok();
                }
                writeln!(output, "):").ok();

                for i in pivot_keyword.keywords.iter() {
                    writeln!(output, "{}", i).ok();
                }
                writeln!(output).ok();

                output
            };

            //ファイル出力の場合
            if let Some(pivot_file) = &configs::CONFIG.read().unwrap().args.output {
                pivot_key_unions.iter().for_each(|(key, pivot_keyword)| {
                    let mut f = BufWriter::new(
                        fs::File::create(
                            pivot_file.as_path().display().to_string() + "-" + key + ".txt",
                        )
                        .unwrap(),
                    );
                    f.write_all(create_output(String::default(), key, pivot_keyword).as_bytes())
                        .unwrap();
                });
                //output to stdout
                let mut output =
                    "Pivot keyword results saved to the following files:\n".to_string();

                pivot_key_unions.iter().for_each(|(key, _)| {
                    writeln!(
                        output,
                        "{}",
                        &(pivot_file.as_path().display().to_string() + "-" + key + ".txt")
                    )
                    .ok();
                });
                write_color_buffer(BufferWriter::stdout(ColorChoice::Always), None, &output).ok();
            } else {
                //標準出力の場合
                let output = "The following pivot keywords were found:".to_string();
                write_color_buffer(BufferWriter::stdout(ColorChoice::Always), None, &output).ok();

                pivot_key_unions.iter().for_each(|(key, pivot_keyword)| {
                    write_color_buffer(
                        BufferWriter::stdout(ColorChoice::Always),
                        None,
                        &create_output(String::default(), key, pivot_keyword),
                    )
                    .ok();
                });
            }
        }
    }

    #[cfg(not(target_os = "windows"))]
    fn collect_liveanalysis_files(&self) -> Option<Vec<PathBuf>> {
        AlertMessage::alert("-l / --liveanalysis needs to be run as Administrator on Windows.")
            .ok();
        println!();
        None
    }

    #[cfg(target_os = "windows")]
    fn collect_liveanalysis_files(&self) -> Option<Vec<PathBuf>> {
        if is_elevated() {
            let log_dir = env::var("windir").expect("windir is not found");
            let evtx_files =
                self.collect_evtxfiles(&[log_dir, "System32\\winevt\\Logs".to_string()].join("/"));
            if evtx_files.is_empty() {
                AlertMessage::alert("No .evtx files were found.").ok();
                return None;
            }
            Some(evtx_files)
        } else {
            AlertMessage::alert("-l / --liveanalysis needs to be run as Administrator on Windows.")
                .ok();
            println!();
            None
        }
    }

    fn collect_evtxfiles(&self, dirpath: &str) -> Vec<PathBuf> {
        let entries = fs::read_dir(dirpath);
        if entries.is_err() {
            let errmsg = format!("{}", entries.unwrap_err());
            if configs::CONFIG.read().unwrap().args.verbose {
                AlertMessage::alert(&errmsg).ok();
            }
            if !*QUIET_ERRORS_FLAG {
                ERROR_LOG_STACK
                    .lock()
                    .unwrap()
                    .push(format!("[ERROR] {}", errmsg));
            }
            return vec![];
        }

        let mut ret = vec![];
        for e in entries.unwrap() {
            if e.is_err() {
                continue;
            }

            let path = e.unwrap().path();
            if path.is_dir() {
                path.to_str().map(|path_str| {
                    let subdir_ret = self.collect_evtxfiles(path_str);
                    ret.extend(subdir_ret);
                    Option::Some(())
                });
            } else if TARGET_EXTENSIONS.contains(
                path.extension()
                    .unwrap_or_else(|| OsStr::new(""))
                    .to_str()
                    .unwrap(),
            ) && !path
                .file_stem()
                .unwrap_or_else(|| OsStr::new("."))
                .to_str()
                .unwrap()
                .starts_with('.')
            {
                ret.push(path);
            }
        }

        ret
    }

    fn print_contributors(&self) {
        match fs::read_to_string("./contributors.txt") {
            Ok(contents) => {
                write_color_buffer(BufferWriter::stdout(ColorChoice::Always), None, &contents).ok();
            }
            Err(err) => {
                AlertMessage::alert(&format!("{}", err)).ok();
            }
        }
    }

    fn analysis_files(&mut self, evtx_files: Vec<PathBuf>, time_filter: &TargetEventTime) {
        let level = configs::CONFIG
            .read()
            .unwrap()
            .args
            .min_level
            .to_uppercase();
        write_color_buffer(
            BufferWriter::stdout(ColorChoice::Always),
            None,
            &format!("Analyzing event files: {:?}", evtx_files.len()),
        )
        .ok();

        let mut total_file_size = ByteSize::b(0);
        for file_path in &evtx_files {
            let meta = fs::metadata(file_path).ok();
            total_file_size += ByteSize::b(meta.unwrap().len());
        }
        println!("Total file size: {}", total_file_size.to_string_as(false));
        println!();
        println!("Loading detections rules. Please wait.");
        println!();

        let rule_files = detection::Detection::parse_rule_files(
            level,
            &configs::CONFIG.read().unwrap().args.rules,
            &filter::exclude_ids(),
        );

        if rule_files.is_empty() {
            AlertMessage::alert(
                "No rules were loaded. Please download the latest rules with the --update-rules option.\r\n",
            )
            .ok();
            return;
        }

        let mut pb = ProgressBar::new(evtx_files.len() as u64);
        pb.show_speed = false;
        self.rule_keys = self.get_all_keys(&rule_files);
        let mut detection = detection::Detection::new(rule_files);
        let mut total_records: usize = 0;
        for evtx_file in evtx_files {
            if configs::CONFIG.read().unwrap().args.verbose {
                println!("Checking target evtx FilePath: {:?}", &evtx_file);
            }
            let cnt_tmp: usize;
            (detection, cnt_tmp) = self.analysis_file(evtx_file, detection, time_filter);
            total_records += cnt_tmp;
            pb.inc();
        }
        if configs::CONFIG.read().unwrap().args.output.is_some() {
            println!();
            println!();
            println!("Analysis finished. Please wait while the results are being saved.");
        }
        println!();
        detection.add_aggcondition_msges(&self.rt);
        if !(*STATISTICS_FLAG || *LOGONSUMMARY_FLAG || *PIVOT_KEYWORD_LIST_FLAG) {
            after_fact(total_records);
        }
    }

    // Windowsイベントログファイルを1ファイル分解析する。
    fn analysis_file(
        &self,
        evtx_filepath: PathBuf,
        mut detection: detection::Detection,
        time_filter: &TargetEventTime,
    ) -> (detection::Detection, usize) {
        let path = evtx_filepath.display();
        let parser = self.evtx_to_jsons(evtx_filepath.clone());
        let mut record_cnt = 0;
        if parser.is_none() {
            return (detection, record_cnt);
        }

        let mut tl = Timeline::new();
        let mut parser = parser.unwrap();
        let mut records = parser.records_json_value();
        loop {
            let mut records_per_detect = vec![];
            while records_per_detect.len() < MAX_DETECT_RECORDS {
                // パースに失敗している場合、エラーメッセージを出力
                let next_rec = records.next();
                if next_rec.is_none() {
                    break;
                }

                let record_result = next_rec.unwrap();
                if record_result.is_err() {
                    let evtx_filepath = &path;
                    let errmsg = format!(
                        "Failed to parse event file. EventFile:{} Error:{}",
                        evtx_filepath,
                        record_result.unwrap_err()
                    );
                    if configs::CONFIG.read().unwrap().args.verbose {
                        AlertMessage::alert(&errmsg).ok();
                    }
                    if !*QUIET_ERRORS_FLAG {
                        ERROR_LOG_STACK
                            .lock()
                            .unwrap()
                            .push(format!("[ERROR] {}", errmsg));
                    }
                    continue;
                }

                // target_eventids.txtでフィルタする。
                let data = record_result.as_ref().unwrap().data.clone();
                let timestamp = record_result.unwrap().timestamp;

                if !self._is_target_event_id(&data) || !time_filter.is_target(&Some(timestamp)) {
                    continue;
                }

                records_per_detect.push(data);
            }
            if records_per_detect.is_empty() {
                break;
            }

            record_cnt += records_per_detect.len();

            let records_per_detect = self.rt.block_on(App::create_rec_infos(
                records_per_detect,
                &path,
                self.rule_keys.clone(),
            ));

            // timeline機能の実行
            tl.start(&records_per_detect);

            if !(*STATISTICS_FLAG || *LOGONSUMMARY_FLAG) {
                // ruleファイルの検知
                detection = detection.start(&self.rt, records_per_detect);
            }
        }

        tl.tm_stats_dsp_msg();
        tl.tm_logon_stats_dsp_msg();

        (detection, record_cnt)
    }

    async fn create_rec_infos(
        records_per_detect: Vec<Value>,
        path: &dyn Display,
        rule_keys: Vec<String>,
    ) -> Vec<EvtxRecordInfo> {
        let path = Arc::new(path.to_string());
        let rule_keys = Arc::new(rule_keys);
        let threads: Vec<JoinHandle<EvtxRecordInfo>> = {
            let this = records_per_detect
                .into_iter()
                .map(|rec| -> JoinHandle<EvtxRecordInfo> {
                    let arc_rule_keys = Arc::clone(&rule_keys);
                    let arc_path = Arc::clone(&path);
                    spawn(async move {
                        utils::create_rec_info(rec, arc_path.to_string(), &arc_rule_keys)
                    })
                });
            FromIterator::from_iter(this)
        };

        let mut ret = vec![];
        for thread in threads.into_iter() {
            ret.push(thread.await.unwrap());
        }

        ret
    }

    fn get_all_keys(&self, rules: &[RuleNode]) -> Vec<String> {
        let mut key_set = HashSet::new();
        for rule in rules {
            let keys = get_detection_keys(rule);
            key_set.extend(keys);
        }

        let ret: Vec<String> = key_set.into_iter().collect();
        ret
    }

    // target_eventids.txtの設定を元にフィルタする。
    fn _is_target_event_id(&self, data: &Value) -> bool {
        let eventid = utils::get_event_value(&utils::get_event_id_key(), data);
        if eventid.is_none() {
            return true;
        }

        match eventid.unwrap() {
            Value::String(s) => utils::is_target_event_id(s),
            Value::Number(n) => utils::is_target_event_id(&n.to_string()),
            _ => true, // レコードからEventIdが取得できない場合は、特にフィルタしない
        }
    }

    fn evtx_to_jsons(&self, evtx_filepath: PathBuf) -> Option<EvtxParser<File>> {
        match EvtxParser::from_path(evtx_filepath) {
            Ok(evtx_parser) => {
                // parserのデフォルト設定を変更
                let mut parse_config = ParserSettings::default();
                parse_config = parse_config.separate_json_attributes(true); // XMLのattributeをJSONに変換する時のルールを設定
                parse_config = parse_config.num_threads(0); // 設定しないと遅かったので、設定しておく。

                let evtx_parser = evtx_parser.with_configuration(parse_config);
                Option::Some(evtx_parser)
            }
            Err(e) => {
                eprintln!("{}", e);
                Option::None
            }
        }
    }

    fn _output_with_omikuji(&self, omikuji: Omikuji) {
        let fp = &format!("art/omikuji/{}", omikuji);
        let content = fs::read_to_string(fp).unwrap();
        println!("{}", content);
    }

    /// output logo
    fn output_logo(&self) {
        let fp = &"art/logo.txt".to_string();
        let content = fs::read_to_string(fp).unwrap_or_default();
        let output_color = if configs::CONFIG.read().unwrap().args.no_color {
            None
        } else {
            Some(Color::Green)
        };
        write_color_buffer(
            BufferWriter::stdout(ColorChoice::Always),
            output_color,
            &content,
        )
        .ok();
    }

    /// output easter egg arts
    fn output_eggs(&self, exec_datestr: &str) {
        let mut eggs: HashMap<&str, &str> = HashMap::new();
        eggs.insert("01/01", "art/happynewyear.txt");
        eggs.insert("02/22", "art/ninja.txt");
        eggs.insert("08/08", "art/takoyaki.txt");
        eggs.insert("12/25", "art/christmas.txt");

        match eggs.get(exec_datestr) {
            None => {}
            Some(path) => {
                let content = fs::read_to_string(path).unwrap_or_default();
                write_color_buffer(BufferWriter::stdout(ColorChoice::Always), None, &content).ok();
            }
        }
    }

    /// update rules(hayabusa-rules subrepository)
    fn update_rules(&self) -> Result<String, git2::Error> {
        let mut result;
        let mut prev_modified_time: SystemTime = SystemTime::UNIX_EPOCH;
        let mut prev_modified_rules: HashSet<String> = HashSet::default();
        let hayabusa_repo = Repository::open(Path::new("."));
        let hayabusa_rule_repo = Repository::open(Path::new("rules"));
        if hayabusa_repo.is_err() && hayabusa_rule_repo.is_err() {
            write_color_buffer(
                BufferWriter::stdout(ColorChoice::Always),
                None,
                "Attempting to git clone the hayabusa-rules repository into the rules folder.",
            )
            .ok();
            // execution git clone of hayabusa-rules repository when failed open hayabusa repository.
            result = self.clone_rules();
        } else if hayabusa_rule_repo.is_ok() {
            // case of exist hayabusa-rules repository
            self._repo_main_reset_hard(hayabusa_rule_repo.as_ref().unwrap())?;
            // case of failed fetching origin/main, git clone is not executed so network error has occurred possibly.
            prev_modified_rules = self.get_updated_rules("rules", &prev_modified_time);
            prev_modified_time = fs::metadata("rules").unwrap().modified().unwrap();
            result = self.pull_repository(&hayabusa_rule_repo.unwrap());
        } else {
            // case of no exist hayabusa-rules repository in rules.
            // execute update because submodule information exists if hayabusa repository exists submodule information.

            prev_modified_time = fs::metadata("rules").unwrap().modified().unwrap();
            let rules_path = Path::new("rules");
            if !rules_path.exists() {
                create_dir(rules_path).ok();
            }
            let hayabusa_repo = hayabusa_repo.unwrap();
            let submodules = hayabusa_repo.submodules()?;
            let mut is_success_submodule_update = true;
            // submodule rules erase path is hard coding to avoid unintentional remove folder.
            fs::remove_dir_all(".git/.submodule/rules").ok();
            for mut submodule in submodules {
                submodule.update(true, None)?;
                let submodule_repo = submodule.open()?;
                if let Err(e) = self.pull_repository(&submodule_repo) {
                    AlertMessage::alert(&format!("Failed submodule update. {}", e)).ok();
                    is_success_submodule_update = false;
                }
            }
            if is_success_submodule_update {
                result = Ok("Successed submodule update".to_string());
            } else {
                result = Err(git2::Error::from_str(&String::default()));
            }
        }
        if result.is_ok() {
            let updated_modified_rules = self.get_updated_rules("rules", &prev_modified_time);
            result =
                self.print_diff_modified_rule_dates(prev_modified_rules, updated_modified_rules);
        }
        result
    }

    /// hard reset in main branch
    fn _repo_main_reset_hard(&self, input_repo: &Repository) -> Result<(), git2::Error> {
        let branch = input_repo
            .find_branch("main", git2::BranchType::Local)
            .unwrap();
        let local_head = branch.get().target().unwrap();
        let object = input_repo.find_object(local_head, None).unwrap();
        match input_repo.reset(&object, git2::ResetType::Hard, None) {
            Ok(()) => Ok(()),
            _ => Err(git2::Error::from_str("Failed reset main branch in rules")),
        }
    }

    /// Pull(fetch and fast-forward merge) repositoryto input_repo.
    fn pull_repository(&self, input_repo: &Repository) -> Result<String, git2::Error> {
        match input_repo
            .find_remote("origin")?
            .fetch(&["main"], None, None)
            .map_err(|e| {
                AlertMessage::alert(&format!("Failed git fetch to rules folder. {}", e)).ok();
            }) {
            Ok(it) => it,
            Err(_err) => return Err(git2::Error::from_str(&String::default())),
        };
        let fetch_head = input_repo.find_reference("FETCH_HEAD")?;
        let fetch_commit = input_repo.reference_to_annotated_commit(&fetch_head)?;
        let analysis = input_repo.merge_analysis(&[&fetch_commit])?;
        if analysis.0.is_up_to_date() {
            Ok("Already up to date".to_string())
        } else if analysis.0.is_fast_forward() {
            let mut reference = input_repo.find_reference("refs/heads/main")?;
            reference.set_target(fetch_commit.id(), "Fast-Forward")?;
            input_repo.set_head("refs/heads/main")?;
            input_repo.checkout_head(Some(git2::build::CheckoutBuilder::default().force()))?;
            Ok("Finished fast forward merge.".to_string())
        } else if analysis.0.is_normal() {
            AlertMessage::alert(
            "update-rules option is git Fast-Forward merge only. please check your rules folder."
                ,
            ).ok();
            Err(git2::Error::from_str(&String::default()))
        } else {
            Err(git2::Error::from_str(&String::default()))
        }
    }

    /// git clone でhauyabusa-rules レポジトリをrulesフォルダにgit cloneする関数
    fn clone_rules(&self) -> Result<String, git2::Error> {
        match Repository::clone(
            "https://github.com/Yamato-Security/hayabusa-rules.git",
            "rules",
        ) {
            Ok(_repo) => {
                println!("Finished cloning the hayabusa-rules repository.");
                Ok("Finished clone".to_string())
            }
            Err(e) => {
                AlertMessage::alert(
                    &format!(
                        "Failed to git clone into the rules folder. Please rename your rules folder name. {}",
                        e
                    ),
                )
                .ok();
                Err(git2::Error::from_str(&String::default()))
            }
        }
    }

    /// Create rules folder files Hashset. Format is "[rule title in yaml]|[filepath]|[filemodified date]|[rule type in yaml]"
    fn get_updated_rules(
        &self,
        rule_folder_path: &str,
        target_date: &SystemTime,
    ) -> HashSet<String> {
        let mut rulefile_loader = ParseYaml::new();
        // level in read_dir is hard code to check all rules.
        rulefile_loader
            .read_dir(
                rule_folder_path,
                "INFORMATIONAL",
                &filter::RuleExclude::default(),
            )
            .ok();

        let hash_set_keys: HashSet<String> = rulefile_loader
            .files
            .into_iter()
            .filter_map(|(filepath, yaml)| {
                let file_modified_date = fs::metadata(&filepath).unwrap().modified().unwrap();

                if file_modified_date.cmp(target_date).is_gt() {
                    let yaml_date = yaml["date"].as_str().unwrap_or("-");
                    return Option::Some(format!(
                        "{}|{}|{}|{}",
                        yaml["title"].as_str().unwrap_or(&String::default()),
                        yaml["modified"].as_str().unwrap_or(yaml_date),
                        &filepath,
                        yaml["ruletype"].as_str().unwrap_or("Other")
                    ));
                }
                Option::None
            })
            .collect();
        hash_set_keys
    }

    /// print updated rule files.
    fn print_diff_modified_rule_dates(
        &self,
        prev_sets: HashSet<String>,
        updated_sets: HashSet<String>,
    ) -> Result<String, git2::Error> {
        let diff = updated_sets.difference(&prev_sets);
        let mut update_count_by_rule_type: HashMap<String, u128> = HashMap::new();
        let mut latest_update_date = Local.timestamp(0, 0);
        for diff_key in diff {
            let tmp: Vec<&str> = diff_key.split('|').collect();
            let file_modified_date = fs::metadata(&tmp[2]).unwrap().modified().unwrap();

            let dt_local: DateTime<Local> = file_modified_date.into();

            if latest_update_date.cmp(&dt_local) == Ordering::Less {
                latest_update_date = dt_local;
            }
            *update_count_by_rule_type
                .entry(tmp[3].to_string())
                .or_insert(0b0) += 1;
            write_color_buffer(
                BufferWriter::stdout(ColorChoice::Always),
                None,
                &format!(
                    "[Updated] {} (Modified: {} | Path: {})",
                    tmp[0], tmp[1], tmp[2]
                ),
            )
            .ok();
        }
        println!();
        for (key, value) in &update_count_by_rule_type {
            println!("Updated {} rules: {}", key, value);
        }
        if !&update_count_by_rule_type.is_empty() {
            Ok("Rule updated".to_string())
        } else {
            write_color_buffer(
                BufferWriter::stdout(ColorChoice::Always),
                None,
                "You currently have the latest rules.",
            )
            .ok();
            Ok("You currently have the latest rules.".to_string())
        }
    }

    /// check architecture
    fn is_matched_architecture_and_binary(&self) -> bool {
        if cfg!(target_os = "windows") {
            let is_processor_arch_32bit = env::var_os("PROCESSOR_ARCHITECTURE")
                .unwrap_or_default()
                .eq("x86");
            // PROCESSOR_ARCHITEW6432は32bit環境には存在しないため、環境変数存在しなかった場合は32bit環境であると判断する
            let not_wow_flag = env::var_os("PROCESSOR_ARCHITEW6432")
                .unwrap_or_else(|| OsString::from("x86"))
                .eq("x86");
            return (cfg!(target_pointer_width = "64") && !is_processor_arch_32bit)
                || (cfg!(target_pointer_width = "32") && is_processor_arch_32bit && not_wow_flag);
        }
        true
    }
}

#[cfg(test)]
mod tests {
    use crate::App;
    use std::time::SystemTime;

    #[test]
    fn test_collect_evtxfiles() {
        let app = App::new();
        let files = app.collect_evtxfiles("test_files/evtx");
        assert_eq!(3, files.len());

        files.iter().for_each(|file| {
            let is_contains = &vec!["test1.evtx", "test2.evtx", "testtest4.evtx"]
                .into_iter()
                .any(|filepath_str| {
                    return file.file_name().unwrap().to_str().unwrap_or("") == filepath_str;
                });
            assert_eq!(is_contains, &true);
        })
    }

    #[test]
    fn test_get_updated_rules() {
        let app = App::new();

        let prev_modified_time: SystemTime = SystemTime::UNIX_EPOCH;

        let prev_modified_rules =
            app.get_updated_rules("test_files/rules/level_yaml", &prev_modified_time);
        assert_eq!(prev_modified_rules.len(), 5);

        let target_time: SystemTime = SystemTime::now();
        let prev_modified_rules2 =
            app.get_updated_rules("test_files/rules/level_yaml", &target_time);
        assert_eq!(prev_modified_rules2.len(), 0);
    }
}