use serde::Deserialize;
use std::{fs, path::PathBuf};

use glob::glob;
use std::{fs::File, io::Write, path::Path};

use crate::template::Template;

/// Store the configuration of config/config.toml
#[derive(Clone, Debug, Default, Deserialize)]
pub struct FileConfiguration {
    /// http/https
    pub scheme: Option<String>,
    /// Domain name "sub.domain.tld"
    pub domain: Option<String>,
    /// Port used
    pub port: Option<u16>,
    /// Mail of owner
    pub mail: Option<String>,
    /// Lang used
    pub lang: Option<String>,
    /// .onion address for Tor of the app
    pub onion: Option<String>,
    /// App name
    pub app_name: Option<String>,
    /// Name of website owner
    pub name: Option<String>,
    /// Fullname of website owner
    pub fullname: Option<String>,
    /// List exclusion for courses
    pub exclude_courses: Option<Vec<String>>,
}

impl FileConfiguration {
    /// Initialize with default values
    fn new() -> Self {
        Self {
            scheme: Some("http".into()),
            domain: Some("localhost".into()),
            port: Some(8080),
            app_name: Some("EWP".into()),
            exclude_courses: Some([].into()),
            ..Self::default()
        }
    }

    /// Complete default structure with an existing one
    fn complete(a: Self) -> Self {
        // Default config
        let d = Self::new();

        #[allow(clippy::items_after_statements)]
        /// Return the default value if nothing is value is none
        fn test<T>(val: Option<T>, default: Option<T>) -> Option<T> {
            if val.is_some() {
                val
            } else {
                default
            }
        }

        Self {
            scheme: test(a.scheme, d.scheme),
            port: test(a.port, d.port),
            mail: test(a.mail, d.mail),
            lang: test(a.lang, d.lang),
            domain: test(a.domain, d.domain),
            onion: test(a.onion, d.onion),
            app_name: test(a.app_name, d.app_name),
            name: test(a.name, d.name),
            fullname: test(a.fullname, d.fullname),
            exclude_courses: test(a.exclude_courses, d.exclude_courses),
        }
    }
}

// Paths where files are stored
#[derive(Clone, Debug)]
pub struct Locations {
    pub static_dir: String,
    pub data_dir: String,
}

/// Configuration used internally in the app
#[derive(Clone, Debug)]
pub struct Config {
    /// Information given in the config file
    pub fc: FileConfiguration,
    /// Location where the static files are stored
    pub locations: Locations,
    /// Informations about templates
    pub tmpl: Template,
}

/// Load the config file
fn get_file_config(file_path: &str) -> FileConfiguration {
    fs::read_to_string(file_path).map_or_else(
        |_| FileConfiguration::new(),
        |file| match toml::from_str(&file) {
            Ok(stored_config) => FileConfiguration::complete(stored_config),
            Err(file_error) => {
                panic!("Error in config file: {file_error}");
            }
        },
    )
}

/// Build the configuration
pub fn get_configuration(file_path: &str) -> Config {
    let internal_config = get_file_config(file_path);

    let static_dir = "static";
    let templates_dir = "templates";
    let files_root = init("dist".into(), static_dir, templates_dir);

    Config {
        fc: internal_config.clone(),
        locations: Locations {
            static_dir: format!("{files_root}/{static_dir}"),
            data_dir: String::from("data"),
        },
        tmpl: Template {
            directory: format!("{files_root}/{templates_dir}"),
            app_name: internal_config.app_name.unwrap(),
            url: internal_config.domain.unwrap(),
            name: internal_config.name,
        },
    }
}

/// Preparation before running the http server
fn init(dist_dir: String, static_dir: &str, templates_dir: &str) -> String {
    // The static folder is minimized only in release mode
    if cfg!(debug_assertions) {
        ".".into()
    } else {
        let cfg = minify_html::Cfg {
            keep_closing_tags: true,
            preserve_brace_template_syntax: true,
            minify_css: true,
            minify_js: true,
            ..minify_html::Cfg::spec_compliant()
        };

        // Static files
        for entry in glob(&format!("{static_dir}/**/*.*")).unwrap() {
            let path = entry.unwrap();
            let path_with_dist = path
                .to_string_lossy()
                .replace(static_dir, &format!("{dist_dir}/{static_dir}"));

            minify_and_copy(&cfg, path, path_with_dist);
        }

        // Template files
        for entry in glob(&format!("{templates_dir}/**/*.*")).unwrap() {
            let path = entry.unwrap();
            let path_with_dist = path
                .to_string_lossy()
                .replace(templates_dir, &format!("{dist_dir}/{templates_dir}"));

            minify_and_copy(&cfg, path, path_with_dist);
        }

        dist_dir
    }
}

/// Minify some assets for production
fn minify_and_copy(cfg: &minify_html::Cfg, path: PathBuf, path_with_dist: String) {
    // Create folders
    let new_path = Path::new(&path_with_dist);
    fs::create_dir_all(new_path.parent().unwrap()).unwrap();

    let session = minify_js::Session::new();
    let mut copy = true;
    if let Some(ext) = path.extension() {
        let js_ext = "js";
        let current_ext = ext.to_string_lossy().to_lowercase();
        // List of files who should be minified
        if ["html", "css", js_ext, "svg", "webmanifest", "xml"].contains(&current_ext.as_str()) {
            // We won't copy, we'll minify
            copy = false;

            // Minify
            let data = fs::read(&path).unwrap();
            let minified = if current_ext == js_ext {
                let mut out = Vec::new();
                minify_js::minify(&session, minify_js::TopLevelMode::Global, &data, &mut out)
                    .unwrap();
                out
            } else {
                minify_html::minify(&data, cfg)
            };

            // Write files
            let file = File::create(&path_with_dist);
            file.expect("Error when minify the file")
                .write_all(&minified)
                .unwrap();
        }
    }

    if copy {
        // If no minification is needed
        fs::copy(path, path_with_dist).unwrap();
    }
}