/*
 * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

#include <aws/common/log_writer.h>

#include <aws/common/string.h>

#include <errno.h>
#include <stdio.h>

#ifdef _MSC_VER
#    pragma warning(disable : 4996) /* Disable warnings about fopen() being insecure */
#endif                              /* _MSC_VER */

/*
 * Basic log writer implementations - stdout, stderr, arbitrary file
 */

struct aws_file_writer;

struct aws_file_writer {
    FILE *log_file;
    bool close_file_on_cleanup;
};

static int s_aws_file_writer_write(struct aws_log_writer *writer, const struct aws_string *output) {
    struct aws_file_writer *impl = (struct aws_file_writer *)writer->impl;

    size_t length = output->len;
    if (fwrite(output->bytes, 1, length, impl->log_file) < length) {
        return aws_translate_and_raise_io_error(errno);
    }

    return AWS_OP_SUCCESS;
}

static void s_aws_file_writer_clean_up(struct aws_log_writer *writer) {
    struct aws_file_writer *impl = (struct aws_file_writer *)writer->impl;

    if (impl->close_file_on_cleanup) {
        fclose(impl->log_file);
    }

    aws_mem_release(writer->allocator, impl);
}

static struct aws_log_writer_vtable s_aws_file_writer_vtable = {
    .write = s_aws_file_writer_write,
    .clean_up = s_aws_file_writer_clean_up,
};

/*
 * Shared internal init implementation
 */
static int s_aws_file_writer_init_internal(
    struct aws_log_writer *writer,
    struct aws_allocator *allocator,
    const char *file_name_to_open,
    FILE *currently_open_file) {

    /* One or the other should be set */
    if (!((file_name_to_open != NULL) ^ (currently_open_file != NULL))) {
        return aws_raise_error(AWS_ERROR_INVALID_ARGUMENT);
    }

    /* Allocate and initialize the file writer */
    struct aws_file_writer *impl = aws_mem_calloc(allocator, 1, sizeof(struct aws_file_writer));
    if (impl == NULL) {
        return AWS_OP_ERR;
    }

    impl->log_file = NULL;
    impl->close_file_on_cleanup = false;

    /* Open file if name passed in */
    if (file_name_to_open != NULL) {
        impl->log_file = fopen(file_name_to_open, "a+");
        if (impl->log_file == NULL) {
            aws_mem_release(allocator, impl);
            return aws_translate_and_raise_io_error(errno);
        }
        impl->close_file_on_cleanup = true;
    } else {
        impl->log_file = currently_open_file;
    }

    writer->vtable = &s_aws_file_writer_vtable;
    writer->allocator = allocator;
    writer->impl = impl;

    return AWS_OP_SUCCESS;
}

/*
 * Public initialization interface
 */
int aws_log_writer_init_stdout(struct aws_log_writer *writer, struct aws_allocator *allocator) {
    return s_aws_file_writer_init_internal(writer, allocator, NULL, stdout);
}

int aws_log_writer_init_stderr(struct aws_log_writer *writer, struct aws_allocator *allocator) {
    return s_aws_file_writer_init_internal(writer, allocator, NULL, stderr);
}

int aws_log_writer_init_file(
    struct aws_log_writer *writer,
    struct aws_allocator *allocator,
    struct aws_log_writer_file_options *options) {
    return s_aws_file_writer_init_internal(writer, allocator, options->filename, options->file);
}

void aws_log_writer_clean_up(struct aws_log_writer *writer) {
    AWS_ASSERT(writer->vtable->clean_up);
    (writer->vtable->clean_up)(writer);
}