// MIT License
//
// Copyright (c) 2024 Rohan Vashisht
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

pub use async_std::task::block_on;
use libc::{
    accept, bind, c_char, c_int, c_void, close, in_addr, listen, recv, sa_family_t, send,
    setsockopt, sockaddr, sockaddr_in, socket, socklen_t, AF_INET, INADDR_ANY, SOCK_STREAM,
    SOL_SOCKET, SO_REUSEPORT,
};
use std::ffi::{CStr, CString};
use std::fs::File;
use std::io::Read;
use std::mem::size_of;

// Define the custom async_main macro.
#[macro_export]
macro_rules! rohanasan {
    // Define the macro pattern.
    ($($body:tt)*) => {
        use $crate::block_on as why_will_someone_use_this_as_a_name_to_import_task_32194ilqrjf8da;
        // Use async-std task spawning to run the asynchronous block provided.
        why_will_someone_use_this_as_a_name_to_import_task_32194ilqrjf8da(async {
            $($body)*
        });
    };
}

const STATIC_FOLDER: &str = "./static/";
/// This is the Default Html Header.
pub const DEFAULT_HTML_HEADER: &str = "HTTP/1.1 200 OK\nContent-Type: text/html\n\n";

/// This is the Default Json Header.
pub const DEFAULT_JSON_HEADER: &str = "HTTP/1.1 200 OK\nContent-Type: text/html\n\n";

/// This is the Default 404 errors' Header.
pub const ERROR_404_HEADER: &str = "HTTP/1.1 404 Not Found\nContent-Type: text/html\n\n";

/// Take this as a parameter in your handle function
/// This contains 5 things:
/// 1) path: This contains the path that the person requested like /hello or /something.
/// 2) method: This contains the method used to send the request like: GET or POST.
/// 3) get_request: This contains the GET requests' parameters (if GET request was made) like: ?q=something%20awesome.
/// 4) protocol: This contains the protocol used to make the HTTP request like:
/// 5) post_request: This contains the POST requests' parameter (if POST request was made) like: {something:something}.
pub struct Request {
    /// path: This contains the path that the person requested like /hello or /something.
    pub path: &'static str,
    /// method: This contains the method used to send the request like: GET or POST.
    pub method: &'static str,
    /// get_request: This contains the GET requests' parameters (if GET request was made) like: ?q=something%20awesome.
    pub get_request: &'static str,
    /// protocol: This contains the protocol used to make the HTTP request like:
    pub protocol: &'static str,
    /// post_request: This contains the POST requests' parameter (if POST request was made) like: {something:something}.
    pub post_request: &'static str,
}

/// Use this function to initialize rohanasan backend framework.
/// Provide this a port datatype: `u16`,
/// use this like this:
/// ```rust
/// use rohanasan::{init, Request, serve, rohanasan};
///
/// fn handle(request: Request) -> &'static str{
///     "Hello!"
/// }
///
/// fn main() {
///     rohanasan! {
///         serve(init(8080), handle).await;
///     }
/// }
/// ```

#[cfg(not(target_os = "linux"))]
pub fn init(port: u16) -> (i32, sockaddr_in, usize) {
    let opt: c_int = 1;

    let server_fd: c_int = unsafe { socket(AF_INET, SOCK_STREAM, 0) };
    if server_fd == -1 {
        panic!("Failed to create socket");
    }
    let address: sockaddr_in = sockaddr_in {
        sin_family: AF_INET as sa_family_t,
        sin_port: unsafe { htons(port) },
        sin_addr: in_addr { s_addr: INADDR_ANY },
        sin_zero: [0; 8],
        sin_len: 1,
    };
    let addrlen: usize = size_of::<sockaddr_in>();
    let res: c_int = unsafe {
        setsockopt(
            server_fd,
            SOL_SOCKET,
            SO_REUSEPORT,
            &opt as *const i32 as *const c_void,
            std::mem::size_of_val(&opt) as socklen_t,
        )
    };
    if res == -1 {
        panic!("Failed to set socket option");
    }
    (server_fd, address, addrlen)
}

/// Use this function to initialize rohanasan backend framework.
/// Provide this a port datatype: `u16`,
/// use this like this:
/// ```rust
/// use rohanasan::{init, Request, serve, rohanasan};
///
/// fn handle(request: Request) -> &'static str{
///     "Hello!"
/// }
///
/// fn main() {
///     rohanasan! {
///         serve(init(8080), handle).await;
///     }
/// }
/// ```
#[cfg(target_os = "linux")]
pub fn init(port: u16) -> (i32, sockaddr_in, usize) {
    let opt: i32 = 1;

    let server_fd: i32 = unsafe { socket(AF_INET, SOCK_STREAM, 0) };
    if server_fd == -1 {
        panic!("Failed to create socket");
    }
    let address: sockaddr_in = sockaddr_in {
        sin_family: AF_INET as sa_family_t,
        sin_port: unsafe { htons(port) },
        sin_addr: in_addr { s_addr: INADDR_ANY },
        sin_zero: [0; 8],
    };
    let addrlen: usize = size_of::<sockaddr_in>();
    let res: i32 = unsafe {
        setsockopt(
            server_fd,
            SOL_SOCKET,
            SO_REUSEADDR,
            &opt as *const i32 as *const c_void,
            size_of::<i32>() as socklen_t,
        )
    };
    if res == -1 {
        panic!("Failed to set socket option");
    }
    (server_fd, address, addrlen)
}

/// Use this function to serve the initialized port according to handle.
/// Provide this the value returned by serve function and a handle function as well,
/// use it like this:
/// ```rust
/// use rohanasan::{init, Request, serve, rohanasan};
///
/// fn handle(request: Request) -> &'static str{
///     "Hello!"
/// }
///
/// fn main() {
///     rohanasan! {
///         serve(init(8080), handle).await;
///     }
/// }
/// ```
pub async fn serve<F>(args: (i32, sockaddr_in, usize), func: F)
where
    F: Fn(Request) -> &'static str + Send + Sync + 'static + Copy,
{
    let (server_fd, address, addrlen) = args;
    let if_bind: i32 = unsafe {
        bind(
            server_fd,
            &address as *const _ as *const sockaddr,
            addrlen as socklen_t,
        )
    };
    if if_bind == -1 {
        panic!("Failed to bind");
    }
    let if_listen = unsafe { listen(server_fd, 3) };
    if if_listen == -1 {
        panic!("Failed to listen");
    }
    loop {
        let new_socket: i32 = unsafe {
            accept(
                server_fd,
                &address as *const _ as *mut sockaddr,
                &addrlen as *const _ as *mut socklen_t,
            )
        };
        if new_socket == -1 {
            continue;
        }
        async_std::task::spawn(async move {
            let mut buf: [c_char; BUFFER_SIZE] = [0; BUFFER_SIZE]; // Allocate buffer
            unsafe {
                recv(
                    new_socket,
                    buf.as_mut_ptr() as *mut c_void,
                    BUFFER_SIZE - 1,
                    0,
                );
                // puts(buf.as_ptr());
            }
            let x: String = String::from_utf8(buf.iter().map(|i| *i as u8).collect::<Vec<_>>())
                .unwrap()
                .clone();
            let tokens = x.leak().split_whitespace().collect::<Vec<&str>>(); // I hate leaks, can someone please provide a better way to do this? :)
            let method = tokens[0];
            let mut path: &str = "";
            let mut get_request = "";
            let mut post_request = "";
            let mut protocol = "";
            if tokens.len() > 2 {
                path = tokens[1].split("?").collect::<Vec<&str>>()[0];
                if tokens[1].split("?").collect::<Vec<&str>>().len() > 1 {
                    get_request = tokens[1].split("?").collect::<Vec<&str>>()[1];
                } else {
                    get_request = "";
                }
                protocol = tokens[2];
                if method == "POST" {
                    post_request = tokens[tokens.len() - 1];
                }
            }
            let the_thing_we_need_to_give_to_func = Request {
                path,
                method,
                get_request,
                protocol,
                post_request,
            };
            if path.starts_with("/static/") && path != "/static/" && path != "/static" {
                let mut file_path = String::from(STATIC_FOLDER);
                file_path.push_str(&path[8..]);
                println!("{}", file_path);

                let file_path_cstr = CString::new(file_path).expect("Invalid file path");
                serve_static_file(new_socket, file_path_cstr.as_ptr());
                unsafe {
                    close(new_socket);
                }
            } else {
                let response = func(the_thing_we_need_to_give_to_func);
                unsafe {
                    send(
                        new_socket,
                        response.as_ptr() as *const c_void,
                        response.len(),
                        0,
                    ); // Use the correct length
                    close(new_socket);
                }
            }
        });
    }
}

pub const BUFFER_SIZE: usize = 1024;

// Function to serve static files

extern "C" {
    fn htons(p0: u16) -> u16;
}

/// Use this function to send a file.
/// Provide this a header and a file path.
/// use it like this:
/// ```rust
/// use rohanasan::{init, Request, serve, DEFAULT_HTML_HEADER, send_file, ERROR_404_HEADER, rohanasan};
///
/// fn handle(request: Request) -> &'static str{
///     if request.path == "/"{
///         send_file(DEFAULT_HTML_HEADER,"./html/index.html")
///     }
///     else {
///         send_file(ERROR_404_HEADER ,"./html/404.html")
///     }
/// }
/// fn main() {
///     rohanasan! {
///         serve(init(8080), handle).await;
///     }
/// }
/// ```
pub fn send_file(header: &str, file_path: &str) -> &'static str {
    let mut file = File::open(file_path).expect("Please enter the correct path to your html file");
    let mut contents = String::new();
    file.read_to_string(&mut contents)
        .expect("File can't be read!");
    send_http_response(header, &*contents)
}

/// Use this function to send an HTTP response.
/// Provide this a header and a body.
/// use it like this:
/// ```rust
/// use rohanasan::{init, Request, serve, DEFAULT_HTML_HEADER, send_http_response, ERROR_404_HEADER, rohanasan};
///
/// fn handle(request: Request) -> &'static str{
///     if request.path == "/"{
///         send_http_response(DEFAULT_HTML_HEADER, "<h1>Hello!</h1>")
///     }
///     else {
///         send_http_response(ERROR_404_HEADER ,"<h1>404</h1>")
///     }
/// }
/// fn main() {
///     rohanasan! {
///         serve(init(8080), handle).await;
///     }
/// }
/// ```
pub fn send_http_response(header: &str, body: &str) -> &'static str {
    let thing: String = header.to_string().clone() + body;
    thing.leak() // I hate leaks, can someone please provide a better way to do this? :)
}
fn serve_static_file(client_socket: c_int, file_path: *const c_char) {
    let file_path_str = unsafe { CStr::from_ptr(file_path).to_string_lossy() };
    let file_path = file_path_str.trim();

    // Attempt to open the file
    let mut file = match File::open(file_path) {
        Ok(file) => file,
        Err(_) => {
            let not_found_response =
                b"HTTP/1.1 404 Not Found\r\nContent-Type: text/html\r\n\r\n<h1>404 Not Found</h1>";
            unsafe {
                send(
                    client_socket,
                    not_found_response.as_ptr() as *const c_void,
                    not_found_response.len(),
                    0,
                );
                close(client_socket);
            }
            return;
        }
    };

    // Determine content type based on file extension
    let content_type = determine_content_type(file_path);

    // Send HTTP response header with correct content type
    let response_header = format!("HTTP/1.1 200 OK\r\nContent-Type: {}\r\n\r\n", content_type);
    let response_header_cstr =
        CString::new(response_header.clone()).expect("Failed to create response header CString");
    unsafe {
        send(
            client_socket,
            response_header_cstr.as_ptr() as *const c_void,
            response_header.len(),
            0,
        )
    };

    // Send file content
    let mut buffer = [0; BUFFER_SIZE];
    loop {
        match file.read(&mut buffer) {
            Ok(0) => break,
            Ok(bytes_read) => {
                unsafe {
                    send(
                        client_socket,
                        buffer.as_ptr() as *const c_void,
                        bytes_read,
                        0,
                    )
                };
            }
            Err(_) => {
                eprintln!("Error reading file");
                break;
            }
        }
    }

    unsafe { close(client_socket) };
}

// Function to determine content type based on file extension
fn determine_content_type(file_path: &str) -> &str {
    match file_path.rsplit('.').next() {
        Some("css") => "text/css",
        Some("txt") => "text/plain",
        Some("js") => "application/javascript",
        Some("png") => "image/png",
        Some("jpg") | Some("jpeg") => "image/jpeg",
        Some("gif") => "image/gif",
        Some("pdf") => "application/pdf",
        Some("htm") | Some("html") => "text/html",
        _ => "application/octet-stream",
    }
}

/// url decode wrapper
/// crate used: url decode, but have made the wrapper suit rohanasan's needs
pub fn decode(x: &str) -> &'static str {
    urldecode::decode(x.to_string()).leak() // Leaks AGAIN!!! I HATE LEAKS! please someone tell me a better alternative to leaks :)
}