/* As of FreeBSD 13.2, sigaction(2) still conforms to IEEE Std
 * 1003.1-1990 (POSIX.1), which did not define SA_RESTART.
 * FreeBSD supports it as an extension, but then _POSIX_C_SOURCE must
 * not be defined. */
#ifndef __FreeBSD__
#define _POSIX_C_SOURCE 200809L
#endif

#include <dynstr.h>
#include <libweb/handler.h>
#include <libweb/html.h>
#include <libweb/http.h>
#include <errno.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int send_response(const unsigned cnt, struct http_response *const r)
{
    int ret = -1;

    struct html_node *html = html_node_alloc("html"), *body, *p;
    struct dynstr d, text;

    dynstr_init(&d);
    dynstr_init(&text);

    if (!html)
    {
        fprintf(stderr, "%s: html_node_alloc failed\n", __func__);
        goto end;
    }
    else if (!(body = html_node_add_child(html, "body")))
    {
        fprintf(stderr, "%s: html_node_add_child body failed\n", __func__);
        goto end;
    }
    else if (!(p = html_node_add_child(body, "p")))
    {
        fprintf(stderr, "%s: html_node_add_child p failed\n", __func__);
        goto end;
    }
    else if (dynstr_append(&text, "It took %u iterations to generate "
        "this response!", cnt))
    {
        fprintf(stderr, "%s: dynstr_append failed\n", __func__);
        goto end;
    }
    else if (html_node_set_value(p, text.str))
    {
        fprintf(stderr, "%s: html_node_set_value p failed\n", __func__);
        goto end;
    }
    else if (html_serialize(html, &d))
    {
        fprintf(stderr, "%s: html_serialize failed\n", __func__);
        goto end;
    }

    *r = (const struct http_response)
    {
        .status = HTTP_STATUS_OK,
        .buf.rw = d.str,
        .n = d.len,
        .free = free
    };

    if (http_response_add_header(r, "Content-Type", "text/html"))
    {
        fprintf(stderr, "%s: http_response_add_header failed\n", __func__);
        goto end;
    }

    ret = 0;

end:
    dynstr_free(&text);
    html_node_free(html);

    if (ret)
        dynstr_free(&d);

    return ret;
}

static int step(const struct http_payload *const pl,
    struct http_response *const r, void *const user, void *args)
{
    unsigned *const cnt = args;
    const unsigned max = 10;

    fprintf(stderr, "%s: step %u\n", __func__, *cnt);

    if (++(*cnt) >= max)
        return send_response(*cnt, r);

    return 0;
}

static int hello(const struct http_payload *const pl,
    struct http_response *const r, void *const user)
{
    unsigned *const cnt = malloc(sizeof *cnt);

    if (!cnt)
    {
        fprintf(stderr, "%s: malloc(3): %s\n", __func__, strerror(errno));
        return -1;
    }

    *r = (const struct http_response)
    {
        .step.payload = step,
        .args = cnt
    };

    *cnt = 0;
    return 0;
}

static int on_length(const enum http_op op, const char *const res,
    const unsigned long long len, const struct http_cookie *const c,
    struct http_response *const r, void *const user)
{
    *r = (const struct http_response)
    {
        .status = HTTP_STATUS_FORBIDDEN
    };

    return 1;
}

struct handler *handler;

static void handle_signal(const int signum)
{
    switch (signum)
    {
        case SIGINT:
            /* Fall through. */
        case SIGTERM:
            handler_notify_close(handler);
            break;

        default:
            break;
    }
}

static int init_signals(void)
{
    struct sigaction sa =
    {
        .sa_handler = handle_signal,
        .sa_flags = SA_RESTART
    };

    sigemptyset(&sa.sa_mask);

    static const struct signal
    {
        int signal;
        const char *name;
    } signals[] =
    {
        {.signal = SIGINT, .name = "SIGINT"},
        {.signal = SIGTERM, .name = "SIGTERM"},
        {.signal = SIGPIPE, .name = "SIGPIPE"}
    };

    for (size_t i = 0; i < sizeof signals / sizeof *signals; i++)
    {
        const struct signal *const s = &signals[i];

        if (sigaction(s->signal, &sa, NULL))
        {
            fprintf(stderr, "%s: sigaction(2) %s: %s\n",
                __func__, s->name, strerror(errno));
            return -1;
        }
    }

    return 0;
}

int main(int argc, char *argv[])
{
    int ret = EXIT_FAILURE;
    const struct handler_cfg cfg =
    {
        .length = on_length
    };

    static const char *const urls[] = {"/", "/index.html"};

    if (!(handler = handler_alloc(&cfg)))
    {
        fprintf(stderr, "%s: handler_alloc failed\n", __func__);
        goto end;
    }

    for (size_t i = 0; i < sizeof urls / sizeof *urls; i++)
        if (handler_add(handler, urls[i], HTTP_OP_GET, hello, NULL))
        {
            fprintf(stderr, "%s: handler_add failed\n", __func__);
            goto end;
        }

    unsigned short outport;

    if (handler_listen(handler, 0, &outport))
    {
        fprintf(stderr, "%s: handler_listen failed\n", __func__);
        goto end;
    }

    printf("Listening on port %hu\n", outport);

    if (handler_loop(handler))
    {
        fprintf(stderr, "%s: handler_loop failed\n", __func__);
        goto end;
    }

    ret = EXIT_SUCCESS;

end:
    handler_free(handler);
    return ret;
}