use rocket::fs::NamedFile;
use rocket::fs::TempFile;
use rocket::http::Method;
use rocket::http::Status;
use rocket::response::Redirect;
use rocket::response::{Responder, status};
use rocket::serde::{Deserialize, json::Json};
use rocket::uri;
use rocket::{self, get, launch, post, put, routes};
use rocket_cors::{AllowedOrigins, CorsOptions};
use std::env;
use std::path::Path;
use std::path::PathBuf;

#[derive(Deserialize)]
#[serde(crate = "rocket::serde")]
struct GenerationRequest<'r> {
    directory: &'r str,
    common_name: &'r str,
    #[serde(default)]
    email: &'r str,
    #[serde(default)]
    days: u32,
    #[serde(default)]
    use_openssl: Option<bool>,
}

#[derive(Responder)]
enum GenerationError {
    #[response(status = 500, content_type = "json")]
    InternalError(String),
    #[response(status = 404, content_type = "json")]
    DirectoryNotFoundError(String),
}

fn get_base_directory() -> String {
    match env::var("GENERATION_BASE_DIRECTORY") {
        Ok(directory) => directory,
        Err(_) => "base/".into(),
    }
}

async fn check_is_valid_directory(
    directory: impl AsRef<Path> + Clone,
) -> Result<(), GenerationError> {
    match tokio::fs::metadata(directory.clone()).await {
        Ok(metadata) => {
            if !metadata.is_dir() {
                return Err(GenerationError::DirectoryNotFoundError(
                    "The specified directory is not valid".into(),
                ));
            }
        }
        Err(_) => {
            return Err(GenerationError::DirectoryNotFoundError(
                "The specified directory is not exists".into(),
            ));
        }
    };

    // Check if the directory contains a 'vars.bat' and 'template.ovpn' files
    const REQUIRED_FILES: [&str; 2] = ["vars.bat", "template.ovpn"];
    for file_name in REQUIRED_FILES.iter() {
        let file_path = directory.as_ref().join(file_name);
        match tokio::fs::metadata(&file_path).await {
            Ok(metadata) => {
                if !metadata.is_file() {
                    return Err(GenerationError::DirectoryNotFoundError(format!(
                        "The specified directory is not valid, invalid file: {}",
                        file_name
                    )));
                }
            }
            Err(_) => {
                return Err(GenerationError::DirectoryNotFoundError(format!(
                    "The specified directory is not valid, missing file: {}",
                    file_name
                )));
            }
        };
    }

    Ok(())
}

#[get("/get")]
async fn list_directories() -> Result<Json<Vec<String>>, status::Custom<String>> {
    let mut reader = tokio::fs::read_dir(get_base_directory())
        .await
        .map_err(|e| {
            status::Custom(
                Status::InternalServerError,
                format!("Failed to read directory: {}", e),
            )
        })?;

    let mut directories = Vec::new();
    while let Ok(Some(entry)) = reader.next_entry().await {
        let path = entry.path();
        if check_is_valid_directory(&path).await.is_ok()
            && let Some(name) = path.file_name() {
                directories.push(name.to_str().unwrap().to_string())
            }
    }

    Ok(Json(directories))
}

#[get("/get/<directory>")]
async fn list_directory(directory: &str) -> Result<Json<Vec<String>>, status::Custom<String>> {
    let base = get_base_directory();
    let dir = Path::new(&base).join(directory);
    if check_is_valid_directory(&dir).await.is_err() {
        return Err(status::Custom(
            Status::BadRequest,
            "The specified directory is not valid".into(),
        ));
    }

    let dir = dir.join("config");
    let mut reader = tokio::fs::read_dir(dir).await.map_err(|e| {
        status::Custom(
            Status::InternalServerError,
            format!("Failed to read directory: {}", e),
        )
    })?;

    let mut files = Vec::new();
    while let Ok(Some(entry)) = reader.next_entry().await {
        let path = entry.path();
        if let Ok(meta) = path.metadata() {
            if !meta.is_file() {
                continue;
            }
            if let Some(ext) = path.extension() {
                if ext.to_str().unwrap() != "ovpn" {
                    continue;
                };
                if let Some(name) = path.file_name() {
                    files.push(name.to_str().unwrap().to_string())
                }
            }
        }
    }

    Ok(Json(files))
}

#[get("/get/<directory>/<file>")]
async fn get_file(directory: &str, file: &str) -> Result<NamedFile, status::NotFound<String>> {
    let dir = Path::new(&get_base_directory()).join(directory);
    if check_is_valid_directory(&dir).await.is_err() {
        return Err(status::NotFound(
            "The specified directory is not valid".into(),
        ));
    }

    let dir = dir.join("config");
    let path = dir.join(file);
    NamedFile::open(&path)
        .await
        .map_err(|e| status::NotFound(e.to_string()))
}

#[put("/put/<directory>/<name>", format = "plain", data = "<file>")]
async fn put_file(directory: &str, name: &str, mut file: TempFile<'_>) -> status::Custom<String> {
    let dir = Path::new(&get_base_directory()).join(directory);
    if check_is_valid_directory(&dir).await.is_err() {
        return status::Custom(
            Status::BadRequest,
            "The specified directory is not valid".into(),
        );
    }

    let dir = dir.join("config");
    let path = dir.join(name);

    // check if the file exists
    match tokio::fs::metadata(&path).await {
        Ok(meta) if meta.is_file() => {}
        _ => {
            return status::Custom(Status::NotFound, "The specified file is not found".into());
        }
    }

    if let Err(msg) = file.persist_to(&path).await {
        return status::Custom(
            Status::InternalServerError,
            format!("Failed to write file: {}", msg),
        );
    }

    status::Custom(Status::NoContent, "".into())
}

#[post("/generate", data = "<request>")]
async fn generate(request: Json<GenerationRequest<'_>>) -> Result<NamedFile, GenerationError> {
    let dir = Path::new(&get_base_directory()).join(request.directory);
    check_is_valid_directory(dir.clone()).await?;

    let generator_bin = env::var("GENERATOR_BIN").unwrap_or("peazyrsa".into());
    let mut cmd = tokio::process::Command::new(generator_bin);

    let mut use_openssl = env::var("USE_OPENSSL").unwrap_or("no".into()) == "yes";
    if let Some(req_use_openssl) = request.use_openssl {
        use_openssl = req_use_openssl;
    }
    if use_openssl {
        let openssl_bin = env::var("OPENSSL_BIN").unwrap_or("openssl".into());
        cmd.arg("--with-openssl").arg(openssl_bin);
    }
    cmd.arg("-d").arg(&dir).arg(request.common_name);

    if !request.email.is_empty() {
        cmd.arg("--email").arg(request.email);
    }

    if request.days > 0 {
        cmd.arg("--days").arg(request.days.to_string());
    }

    // execute the command and check error code
    let status = cmd
        .status()
        .await
        .map_err(|e| GenerationError::InternalError(format!("Failed to execute command: {}", e)))?;
    if !status.success() {
        return Err(GenerationError::InternalError(format!(
            "Command failed with status: {}",
            status
        )));
    }

    // check output file exists
    let output_file = dir
        .join("config")
        .join(format!("{}.ovpn", request.common_name));
    if !output_file.exists() {
        return Err(GenerationError::InternalError(
            "Output file not found".into(),
        ));
    }

    match NamedFile::open(output_file).await {
        Err(e) => Err(GenerationError::InternalError(format!(
            "Failed to open output file: {}",
            e
        ))),
        Ok(f) => Ok(f),
    }
}

#[get("/")]
fn index_redirect() -> Redirect {
    Redirect::permanent(uri!("/frontend").to_string() + "/")
}

#[get("/frontend/<path..>")]
async fn frontend(path: PathBuf) -> Option<NamedFile> {
    let frontend_base = env::var("FRONTEND_BASE").unwrap_or("../frontend/dist/".into());
    let frontend_path = Path::new(&frontend_base).join(path);
    let frontend_index_path = Path::new(&frontend_base).join("index.html");

    match tokio::fs::metadata(&frontend_path).await {
        Ok(meta) if meta.is_file() => NamedFile::open(frontend_path)
            .await
            .or(NamedFile::open(frontend_index_path).await)
            .ok(),
        _ => NamedFile::open(&frontend_index_path).await.ok(),
    }
}

#[launch]
fn rocket() -> _ {
    let cors = CorsOptions::default()
        .allowed_origins(AllowedOrigins::all())
        .allowed_methods(
            vec![Method::Get, Method::Post, Method::Put]
                .into_iter()
                .map(From::from)
                .collect(),
        )
        .allow_credentials(true);

    rocket::build()
        .mount(
            "/api/v1",
            routes![
                list_directories,
                list_directory,
                get_file,
                put_file,
                generate
            ],
        )
        .attach(cors.to_cors().unwrap())
        .mount("/", routes![index_redirect, frontend])
}