#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <uv.h>

#define DEFAULT_PORT 7000

#define DEFAULT_BACKLOG 128

uv_loop_t *loop;

struct sockaddr_in addr;

typedef struct {

    uv_write_t req;

    uv_buf_t buf;

} write_req_t;

void free_write_req(uv_write_t *req) {

    write_req_t *wr = (write_req_t*) req;

    free(wr->buf.base);

    free(wr);

}

void alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf) {

    buf->base = (char*) malloc(suggested_size);

    buf->len = suggested_size;

}

void on_close(uv_handle_t* handle) {

    free(handle);

}

void echo_write(uv_write_t *req, int status) {

    if (status) {

        fprintf(stderr, "Write error %s\n", uv_strerror(status));

    }

    free_write_req(req);

}

void echo_read(uv_stream_t *client, ssize_t nread, const uv_buf_t *buf) {

    if (nread > 0) {

        write_req_t *req = (write_req_t*) malloc(sizeof(write_req_t));

        req->buf = uv_buf_init(buf->base, nread);

        uv_write((uv_write_t*) req, client, &req->buf, 1, echo_write);

        return;

    }

    if (nread < 0) {

        if (nread != UV_EOF)

            fprintf(stderr, "Read error %s\n", uv_err_name(nread));

        uv_close((uv_handle_t*) client, on_close);

    }

    free(buf->base);

}

void on_new_connection(uv_stream_t *server, int status) {

    if (status < 0) {

        fprintf(stderr, "New connection error %s\n", uv_strerror(status));

        // error!

        return;

    }

    uv_tcp_t *client = (uv_tcp_t*) malloc(sizeof(uv_tcp_t));

    uv_tcp_init(loop, client);

    if (uv_accept(server, (uv_stream_t*) client) == 0) {

        uv_read_start((uv_stream_t*) client, alloc_buffer, echo_read);

    }

    else {

        uv_close((uv_handle_t*) client, on_close);

    }

}

int main() {

    loop = uv_default_loop();

    uv_tcp_t server;

    uv_tcp_init(loop, &server);

    uv_ip4_addr("0.0.0.0", DEFAULT_PORT, &addr);

    uv_tcp_bind(&server, (const struct sockaddr*)&addr, 0);

    int r = uv_listen((uv_stream_t*) &server, DEFAULT_BACKLOG, on_new_connection);

    if (r) {

        fprintf(stderr, "Listen error %s\n", uv_strerror(r));

        return 1;

    }

    return uv_run(loop, UV_RUN_DEFAULT);

}