/**
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0.
 */

#include <aws/auth/private/sigv4_http_request.h>

#include <aws/auth/credentials.h>
#include <aws/auth/signable.h>
#include <aws/auth/signing.h>
#include <aws/auth/signing_result.h>
#include <aws/common/condition_variable.h>
#include <aws/common/mutex.h>
#include <aws/common/string.h>
#include <aws/http/request_response.h>
#include <aws/io/uri.h>

#if defined(_MSC_VER)
#    pragma warning(disable : 4204)
#endif /* _MSC_VER */

#define DEFAULT_QUERY_PARAM_COUNT 10

/*
 * Uses the signing result to rebuild the request's URI.  If the signing was not done via
 * query params, then this ends up doing nothing.
 */
static int s_build_request_uri(
    struct aws_allocator *allocator,
    struct aws_http_message *request,
    const struct aws_signing_result *signing_result) {

    /* first let's see if we need to do anything at all */
    struct aws_array_list *result_param_list = NULL;
    aws_signing_result_get_property_list(
        signing_result, g_aws_http_query_params_property_list_name, &result_param_list);
    if (result_param_list == NULL) {
        return AWS_OP_SUCCESS;
    }

    /*
     * There are query params to apply.  Use the following algorithm:
     *
     * (1) Take the old uri and parse it into a URI structure
     * (2) Make a new URI builder and add the old URI's components to it
     * (3) Add the signing query params to the builder
     * (4) Use the builder to make a new URI
     */
    int result = AWS_OP_ERR;
    size_t signed_query_param_count = aws_array_list_length(result_param_list);

    struct aws_uri old_uri;
    AWS_ZERO_STRUCT(old_uri);

    struct aws_uri new_uri;
    AWS_ZERO_STRUCT(new_uri);

    struct aws_uri_builder_options new_uri_builder;
    AWS_ZERO_STRUCT(new_uri_builder);

    struct aws_array_list query_params;
    AWS_ZERO_STRUCT(query_params);

    struct aws_byte_cursor old_path;
    aws_http_message_get_request_path(request, &old_path);

    /* start with the old uri and parse it */
    if (aws_uri_init_parse(&old_uri, allocator, &old_path)) {
        goto done;
    }

    /* pull out the old query params */
    if (aws_array_list_init_dynamic(
            &query_params, allocator, DEFAULT_QUERY_PARAM_COUNT, sizeof(struct aws_uri_param))) {
        goto done;
    }

    if (aws_uri_query_string_params(&old_uri, &query_params)) {
        goto done;
    }

    /* initialize a builder for the new uri matching the old uri */
    new_uri_builder.host_name = old_uri.host_name;
    new_uri_builder.path = old_uri.path;
    new_uri_builder.port = old_uri.port;
    new_uri_builder.scheme = old_uri.scheme;
    new_uri_builder.query_params = &query_params;

    /* and now add any signing query params */
    for (size_t i = 0; i < signed_query_param_count; ++i) {
        struct aws_signing_result_property source_param;
        if (aws_array_list_get_at(result_param_list, &source_param, i)) {
            goto done;
        }

        struct aws_uri_param signed_param;
        signed_param.key = aws_byte_cursor_from_string(source_param.name);
        signed_param.value = aws_byte_cursor_from_string(source_param.value);

        aws_array_list_push_back(&query_params, &signed_param);
    }

    /* create the new uri */
    if (aws_uri_init_from_builder_options(&new_uri, allocator, &new_uri_builder)) {
        goto done;
    }

    /* copy the full string */
    struct aws_byte_cursor new_uri_cursor = aws_byte_cursor_from_buf(&new_uri.uri_str);
    if (aws_http_message_set_request_path(request, new_uri_cursor)) {
        goto done;
    }

    result = AWS_OP_SUCCESS;

done:

    aws_array_list_clean_up(&query_params);

    aws_uri_clean_up(&new_uri);
    aws_uri_clean_up(&old_uri);

    return result;
}

/*
 * Takes a mutable http request and adds all the additional query params and/or headers generated by the
 * signing process.
 */
int aws_apply_signing_result_to_http_request(
    struct aws_http_message *request,
    struct aws_allocator *allocator,
    const struct aws_signing_result *result) {

    /* uri/query params */
    if (s_build_request_uri(allocator, request, result)) {
        return AWS_OP_ERR;
    }

    /* headers */
    size_t signing_header_count = 0;
    struct aws_array_list *result_header_list = NULL;
    aws_signing_result_get_property_list(result, g_aws_http_headers_property_list_name, &result_header_list);
    if (result_header_list != NULL) {
        signing_header_count = aws_array_list_length(result_header_list);
    }

    for (size_t i = 0; i < signing_header_count; ++i) {
        struct aws_signing_result_property source_header;
        AWS_ZERO_STRUCT(source_header);

        if (aws_array_list_get_at(result_header_list, &source_header, i)) {
            return AWS_OP_ERR;
        }

        if (source_header.name == NULL || source_header.value == NULL) {
            return aws_raise_error(AWS_ERROR_INVALID_ARGUMENT);
        }

        struct aws_http_header dest_header = {
            .name = aws_byte_cursor_from_string(source_header.name),
            .value = aws_byte_cursor_from_string(source_header.value),
        };
        aws_http_message_add_header(request, dest_header);
    }

    return AWS_OP_SUCCESS;
}