import json
import typing

import liquid
from flask import url_for, current_app

from core_notifications.analytics import emails_events
from core_notifications.consts import SystemEvents
from core_notifications.helpers.services import BaseLogicService
from core_notifications.logs import logger
from core_notifications.models import DNAAccount, Template, TemplateVersion
from core_notifications.tasks import send_email_task


class CreateTemplateService(BaseLogicService):
    """Create new template instance and saves into DB."""

    def process(
        self,
        name: str,
        subject: str,
        source: str,
        context: str,
        dna_account: DNAAccount,
        is_active: bool,
        **kwargs,
    ) -> Template:
        template = Template()
        template.name = name
        template.subject = subject
        template.source = source
        template.context = context
        template.is_active = is_active
        template.created_by = dna_account
        template.updated_by = dna_account
        self.session.add(template)
        template.versions.append(TemplateVersion.from_template(template))
        return template


class UpdateTemplateService(BaseLogicService):
    """Updates existing template instance and saves into DB."""

    def process(
        self,
        template: Template,
        name: str,
        subject: str,
        source: str,
        context: str,
        dna_account: DNAAccount,
        is_active: bool,
        **kwargs,
    ) -> Template:
        need_version = (
            template.name != name
            or template.subject != subject
            or template.source != source
            or template.context != context
        )
        template.name = name
        template.subject = subject
        template.source = source
        template.context = context
        template.updated_by = dna_account
        template.is_active = is_active
        if need_version:
            self.session.add(TemplateVersion.from_template(template))
        return template


class EnableDisableTemplateService(BaseLogicService):
    """Enables or disables existing template instance and saves into DB."""

    def process(
        self,
        template: Template,
        is_active: bool,
        dna_account: DNAAccount,
        **kwargs,
    ) -> Template:
        template.is_active = is_active
        template.updated_by = dna_account
        return template


class RenderLiquidService(BaseLogicService):
    """
    Renders the template with Liquid engine.

    Fails silently on eny errors in source or context.
    The data is intended to be prevalidated.
    """

    commit = False

    def process(
        self, source: str, context: typing.Union[typing.Mapping, str], **kwargs
    ) -> str:
        if not isinstance(context, typing.Mapping):
            try:
                context = json.loads(context)
            except Exception as e:
                logger.bind(context=context, error=e).warning(
                    "Invalid context data"
                )
                context = {}
        try:
            result = liquid.Template(source).render(context)
        except Exception as e:
            logger.bind(error=e).warning("Invalid template source")
            result = ""
        return result


class SendTestEmailService(BaseLogicService):
    """Sending test email for specified template."""

    commit = False

    def process(self, template: Template, email: str):
        subject = RenderLiquidService.execute(
            template.subject, template.context
        )
        body = RenderLiquidService.execute(template.source, template.context)
        task_id = send_email_task.delay(
            subject=subject,
            to=email,
            body=body,
            analytic_url=url_for(
                "analytics.link_click",
                _external=True,
            ),
            analytics={
                "subject": subject,
                "template_id": template.id,
                "template_name": template.name,
                "user_id": current_app.config.get("ANALYTICS_USER_ID"),
                "user_name": current_app.config.get("ANALYTICS_USER_NAME"),
            },
            track_clicks=True,
        ).task_id
        emails_events.log(
            SystemEvents.sending_email,
            id=task_id,
            template_id=template.id,
            template_name=template.name,
            to=email,
            subject=subject,
            user_id=current_app.config.get("ANALYTICS_USER_ID"),
            user_name=current_app.config.get("ANALYTICS_USER_NAME"),
        )