use std::{cmp, io::ErrorKind};

use actix_web::HttpRequest;
use time::Duration;
use tokio::fs;

use crate::config::Config;

const INDEX_HTML: &str = include_str!("../template/index.html");
const AUTH_HIDE_JS: &str = include_str!("../template/auth-hide.js");
const AUTH_SNIPPET_HTML: &str = include_str!("../snippet/auth.html.snippet");
const MAX_SIZE_SNIPPET_HTML: &str = include_str!("../snippet/max_size.html.snippet");

pub async fn write_prefillable_templates(config: &Config) {
    let index_html = build_index_html(config);
    let auth_hide_js = build_auth_hide_js(config);
    let index_path = config.static_dir.join("index.html");
    let auth_hide_path = config.static_dir.join("auth-hide.js");

    fs::write(index_path, index_html)
        .await
        .expect("could not write index.html to static folder");
    if let Some(auth_hide_js) = auth_hide_js {
        fs::write(auth_hide_path, auth_hide_js)
            .await
            .expect("could not write auth-hide.js to static folder");
    } else {
        match fs::remove_file(auth_hide_path).await {
            Err(err) if err.kind() == ErrorKind::NotFound => {}
            r => r.expect("could not delete auth-hide.js from static folder"),
        }
    }
}

fn build_index_html(config: &Config) -> String {
    let auth_snippet = config
        .no_auth_limits
        .as_ref()
        .map_or("", |_| AUTH_SNIPPET_HTML);
    let max_size_snippet = config
        .max_file_size
        .as_ref()
        .map_or("", |_| MAX_SIZE_SNIPPET_HTML);
    INDEX_HTML
        .replace("{max_size_snippet}", max_size_snippet)
        .replace(
            "{max_size}",
            &render_file_size(config.max_file_size.unwrap_or(0)),
        )
        .replace("{auth_snippet}", auth_snippet)
        .replace(
            "{auth_time}",
            &config
                .no_auth_limits
                .as_ref()
                .map(|limit| limit.max_time)
                .map_or("".into(), render_duration),
        )
        .replace(
            "{auth_large_time}",
            &config
                .no_auth_limits
                .as_ref()
                .map(|limit| limit.large_file_max_time)
                .map_or("".into(), render_duration),
        )
        .replace(
            "{auth_large_size}",
            &config
                .no_auth_limits
                .as_ref()
                .map(|limit| limit.large_file_size)
                .map_or("".into(), render_file_size),
        )
}

fn render_file_size(size: u64) -> String {
    let magnitude = cmp::min((size as f64).log(1024.0) as u32, 5);
    let prefix = ["", "ki", "Mi", "Gi", "Ti", "Pi"][magnitude as usize];
    let value = size / (1024_u64.pow(magnitude));
    format!("{}{}B", value, prefix)
}

fn render_duration(duration: Duration) -> String {
    let days = duration.whole_days();
    let hours = duration.whole_hours() % 24;
    let minutes = duration.whole_minutes() % 60;
    let seconds = duration.whole_seconds() % 60;
    let mut elements = vec![];
    if let Some(name) = pluralize(days, "tag", "e") {
        elements.push(name);
    }
    if let Some(name) = pluralize(hours, "stunde", "n") {
        elements.push(name);
    }
    if let Some(name) = pluralize(minutes, "minute", "n") {
        elements.push(name);
    }
    if let Some(name) = pluralize(seconds, "sekunde", "n") {
        elements.push(name);
    }
    elements.join("+")
}

fn pluralize(number: i64, word: &str, suffix: &str) -> Option<String> {
    match number {
        0 => None,
        1 => Some(format!("{} {}", number, word)),
        _ => Some(format!("{} {}{}", number, word, suffix)),
    }
}

fn build_auth_hide_js(config: &Config) -> Option<String> {
    if let Some(no_auth_limits) = &config.no_auth_limits {
        let auth_hide_js = AUTH_HIDE_JS
            .replace(
                "{no_auth_max_time}",
                &no_auth_limits.max_time.whole_seconds().to_string(),
            )
            .replace(
                "{no_auth_large_file_max_time}",
                &no_auth_limits
                    .large_file_max_time
                    .whole_seconds()
                    .to_string(),
            )
            .replace(
                "{no_auth_large_file_size}",
                &no_auth_limits.large_file_size.to_string(),
            );
        Some(auth_hide_js)
        // Ok(HttpResponse::Ok()
        //     .content_type("application/javascript")
        //     .body(auth_hide_js))
    } else {
        None
        // Err(error::ErrorNotFound("file not found"))
    }
}

pub fn get_host_url(req: &HttpRequest) -> String {
    let conn = req.connection_info();
    format!("{}://{}", conn.scheme(), conn.host())
}