import boto3

from labelaudit import config
from labelaudit.consts import report_column_headings
from labelaudit.logic import audit_persistence
from labelaudit.logic import audit_prep_report
from labelaudit.logic.stream_to_s3 import StreamToS3


HTML_EMAIL_BODY = """
        Hello, <br/><br/>  The requested Audit doc for Label {} has
        been completed. Please download
        <a href="{}/youtubeaudit/index/vendor_id/{}">
        here</a>."""

TEXT_EMAIL_BODY = """
        Hello, The requested Audit doc for Label {} has
        been completed. Please download it here:
        {}/youtubeaudit/vendorId/{}
        """


def generate(report):
    """Generate an audit report and write to s3.

    Updates the audit report status to complete on success.

    Args:
        report (dict): see labelaudit.tasks.report_generation_tasks
    """

    youtube_audit_id = report.get('youtubeAuditId')
    limit = total = config.NUM_RELEASES_WRITE_CSV
    offset = 0
    bucket_root = config.S3_BUCKET_ROOT or ''
    vendor_id = report.get('vendorId')
    s3_key = '{}{}/{}.csv'.format(
        bucket_root, vendor_id, youtube_audit_id)

    # Write location of file we are creating to the db
    # TODO abstract the path generation and move this back to
    # where we set status to 'generating'
    write_report_path(youtube_audit_id, config.S3_BUCKET, s3_key)

    # TODO log that we are starting to write a file to S3
    with StreamToS3(
            s3_key, config.S3_BUCKET,
            report_column_headings.VAPI_REPORT_FIELDNAMES,
            report_column_headings.REPORT_COLUMN_HEADINGS) as s:
        s.write_column_headers()
        while offset < total:
            rows = audit_prep_report.fetch(
                youtubeAuditId=youtube_audit_id, offset=offset, limit=limit)
            if (rows.errors):
                raise Exception(
                    'Error getting report rows for generation: {}'
                    .format(rows.errors))

            total = rows.message.get('total_records')
            # stream results to S3 file one offset batch at a time
            s.write_batch_rows(rows.message.get('report_rows'))
            offset += limit

    audit_persistence.update_report_status(youtube_audit_id, 'complete')
    email_notification(vendor_id)


def email_notification(vendor_id):
    """Email auditor that report is ready for download.

    Args:
        vendor_id (int): label id for the report
    """

    conn = boto3.client('ses', region_name=config.AWS_REGION)
    conn.send_email(
        source=config.EMAIL_FROM_ADDRESS,
        subject='Vendor {} - Label Audit Prep Doc Completed'.format(vendor_id),
        body=TEXT_EMAIL_BODY.format(vendor_id, config.OA_URL, vendor_id),
        html_body=HTML_EMAIL_BODY.format(vendor_id, config.OA_URL, vendor_id),
        to_addresses=[config.EMAIL_TO_ADDRESS])


def write_report_path(youtube_audit_id, bucket, key):
    """Write storage path of the audit report to db via VAPI.

    Args:
        youtube_audit_id (int)
        bucket (str): s3 bucket without trailing slash
        key (str): s3 key
    """

    full_s3_path = '{}/{}'.format(bucket, key)
    audit_persistence.update(youtube_audit_id, {
        'reportLocation': full_s3_path})