"""API utilities."""
import functools
import os


from flask import g
from flask import request
from marshmallow import ValidationError

from asset_transcoder.constants import asset_upload as asset_upload_constants
from asset_transcoder.utils.exceptions import OwsError


def _get_request_context():
    """Get global context."""
    return g.request_context


def get_user_id():
    """Get user_id from global context."""
    context = _get_request_context()
    if context.identity_uuid:
        return context.identity_uuid
    elif context.identity_id:
        return context.identity_id
    elif context.context_type == 'account' and context.orchard_user_id:
        return context.orchard_user_id
    raise OwsError(message='Failed to identify user', status=401)


def get_app_by_object_type(object_type):
    """Get application name by object type."""
    related_app = None
    for app, obj_types in asset_upload_constants.OBJECT_APP_RELATION.items():
        if object_type in obj_types:
            related_app = app
            break
    if not related_app:
        raise OwsError.bad_request(
            'object type {object_type} is not supported'.format(
                object_type=object_type))
    return related_app


def get_pipeline_config(object_type):
    """Get config object for lambda's pipeline."""
    related_app = get_app_by_object_type(object_type)

    return {
        'output_bucket_name': os.environ.get(
            'OUTPUT_ASSETS_{0}_BUCKET_NAME'.format(related_app)),
        'preview_bucket_name': os.environ.get(
            'PREVIEW_ASSETS_{0}_BUCKET_NAME'.format(related_app)),
        'elastic_transcoder_id': os.environ.get(
            'ELASTIC_TRANSCODER_{0}_ID'.format(related_app))
    }


def utc_format(date):
    """Convert datetime to utc string."""
    return date.isoformat()


def utc_format_with_z(date):
    """Convert datetime to utc string."""
    return utc_format(date) + '.000Z'


def validate_request_data(schema, partial=False):
    """Decorate requests' input data validation.

    Args:
        schema (marshmallow.Schema()): schema instance to apply
        partial (bool): validate only derived fields
    """
    def validator(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            data = request.get_json()
            try:
                validated = schema.load(data, partial=partial)
            except ValidationError as err:
                raise OwsError.bad_request(err.messages)
            else:
                return func(*args, data=validated, **kwargs)
        return wrapper
    return validator


def validate_request_query(schema, partial=False):
    """Decorate requests' input query string validation.

    Args:
        schema (marshmallow.Schema()): schema instance to apply
        partial (bool): validate only derived fields
    """
    def validator(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            data = request.args
            try:
                validated = schema.load(data, partial=partial)
            except ValidationError as err:
                raise OwsError.bad_request(err.messages)
            else:
                return func(*args, data=validated, **kwargs)
        return wrapper
    return validator


def asset_url(filename, object_type):
    """Get full asset url for given objct type.

    Args:
        filename (str): uri part of url
        object_type (str): asset upload object type
    """
    related_app = get_app_by_object_type(object_type)
    output_cdn = os.environ.get('OUTPUT_{0}_CDN'.format(related_app))
    if not output_cdn:
        raise OwsError.bad_request('cdn value for {} not found'.format(object_type))
    return 'https://{}/{}'.format(output_cdn, filename)