#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include "http_response.h"
#include "http_server.h"
#include "http_response_cache.h"
#include "hw_string.h"

#define CRLF "\r\n"
KHASH_MAP_INIT_STR(string_hashmap, char *)

hw_http_response hw_create_http_response(http_connection *connection) {
    http_response *response     = malloc(sizeof(http_response));
    response->connection        = connection;
    response->request           = connection->request;
    response->http_major        = 1;
    response->http_minor        = 1;
    response->body.value        = NULL;
    response->body.length       = 0;
    response->number_of_headers = 0;
    return response;
}

void hw_free_http_response(hw_http_response *response) {
    http_response *resp = (http_response *)response;
    free(resp);
}

void hw_set_http_version(hw_http_response *response, unsigned short major, unsigned short minor) {
    http_response *resp = (http_response *)response;
    resp->http_major    = major;
    resp->http_minor    = minor;
}

void hw_set_response_status_code(hw_http_response *response, hw_string *status_code) {
    http_response *resp = (http_response *)response;
    resp->status_code   = *status_code;
}

void hw_set_response_header(hw_http_response *response, hw_string *name, hw_string *value) {
    http_response *resp                    = (http_response *)response;
    http_header   *header                  = &resp->headers[resp->number_of_headers];
    header->name                           = *name;
    header->value                          = *value;
    resp->headers[resp->number_of_headers] = *header;
    resp->number_of_headers++;
}

void hw_set_body(hw_http_response *response, hw_string *body) {
    http_response *resp = (http_response *)response;
    resp->body          = *body;
}

int num_chars(int n) {
    int r = 1;
    if (n < 0) {
        n = (n == INT_MIN) ? INT_MAX : -n;
    }
    while (n > 9) {
        n /= 10;
        r++;
    }
    return r;
}

hw_string *create_response_buffer(hw_http_response *response) {
    http_response *resp            = (http_response *)response;
    hw_string     *response_string = malloc(sizeof(hw_string));
    hw_string     *cached_entry    = get_cached_request(resp->status_code.value);
    hw_string      content_length;

    int i = 0;

    char length_header[] = "Content-Length: ";
    int  line_sep_size   = sizeof(CRLF);

    int header_buffer_incr    = 512;
    int body_size             = resp->body.length;
    int header_size_remaining = header_buffer_incr;
    int response_size = header_size_remaining + sizeof(length_header) + num_chars(resp->body.length) + 2 * line_sep_size
        + body_size + line_sep_size;

    response_string->value = malloc(response_size);

    response_string->length = 0;
    append_string(response_string, cached_entry);

    for (i = 0; i < resp->number_of_headers; i++) {
        http_header header = resp->headers[i];

        header_size_remaining -= header.name.length + 2 + header.value.length + line_sep_size;
        if (header_size_remaining < 0) {
            header_size_remaining += header_buffer_incr * ((-header_size_remaining / header_buffer_incr) + 1);
            response_size += header_size_remaining;
            response_string->value = realloc(response_string->value, response_size);
        }

        append_string(response_string, &header.name);
        APPENDSTRING(response_string, ": ");
        append_string(response_string, &header.value);
        APPENDSTRING(response_string, CRLF);
    }

    /* Add the body */
    APPENDSTRING(response_string, length_header);

    string_from_int(&content_length, body_size, 10);

    if (body_size > 0) {
        append_string(response_string, &content_length);
    } else {
        hw_string zero_content;
        zero_content.value  = "0";
        zero_content.length = 1;
        append_string(response_string, &zero_content);
    }

    APPENDSTRING(response_string, CRLF CRLF);

    if (body_size > 0) {
        append_string(response_string, &resp->body);
    }

    return response_string;
}

void hw_http_response_send(hw_http_response *response, void *user_data, http_response_complete_callback callback) {
    hw_write_context *write_context   = malloc(sizeof(hw_write_context));
    http_response    *resp            = (http_response *)response;
    hw_string        *response_buffer = create_response_buffer(response);

    write_context->connection = resp->connection;
    write_context->user_data  = user_data;
    write_context->callback   = callback;
    write_context->request    = resp->request;

    http_server_write_response(write_context, response_buffer);
    resp->sent = 1;

    free(response_buffer);
    hw_free_http_response(response);
}

void hw_http_response_send_error(hw_http_response *response, const char *error, const char *err_msg) {
    hw_string status_code;
    hw_string content_type_name;
    hw_string content_type_value;
    hw_string body;
    hw_string keep_alive_name;
    hw_string keep_alive_value;

    SETSTRING(content_type_name, "Content-Type");
    SETSTRING(content_type_value, "text/html");
    hw_set_response_header(response, &content_type_name, &content_type_value);

    SETSTRING(status_code, error);
    SETSTRING(body, err_msg);

    hw_set_body(response, &body);
    hw_set_response_status_code(response, &status_code);

    SETSTRING(keep_alive_name, "Connection");
    SETSTRING(keep_alive_value, "close");
    hw_set_response_header(response, &keep_alive_name, &keep_alive_value);

    hw_http_response_send(response, NULL, NULL);
}