import datetime
import logging
from typing import Tuple, List

from app import db
from app.models.bridges import BridgeConf, Bridge
from app.terraform import BaseAutomation
from app.terraform.bridge.gandi import BridgeGandiAutomation
from app.terraform.bridge.hcloud import BridgeHcloudAutomation
from app.terraform.bridge.ovh import BridgeOvhAutomation

BRIDGE_PROVIDERS = {p.provider: p for p in [
    # In order of cost
    BridgeHcloudAutomation,
    BridgeGandiAutomation,
    BridgeOvhAutomation,
    # BridgeAWSAutomation,  TODO: This module is broken right now
] if p.enabled}


def create_bridges(bridgeconf: BridgeConf, count: int) -> int:
    """
    Creates a bridge resource for the given bridge configuration.
    """
    logging.debug("Creating %s bridges for configuration %s", count, bridgeconf.id)
    created = 0
    # TODO: deal with the fact that I created a dictionary and then forgot it wasn't ordered
    while created < count:
        for provider in BRIDGE_PROVIDERS:
            if BRIDGE_PROVIDERS[provider].max_bridges > BRIDGE_PROVIDERS[provider].active_bridges_count():
                logging.debug("Creating bridge for configuration %s with provider %s", bridgeconf.id, provider)
                bridge = Bridge()
                bridge.pool_id = bridgeconf.pool.id
                bridge.conf_id = bridgeconf.id
                bridge.provider = provider
                bridge.added = datetime.datetime.utcnow()
                bridge.updated = datetime.datetime.utcnow()
                logging.debug("Creating bridge %s", bridge)
                db.session.add(bridge)
                created += 1
                break
            else:
                logging.debug("No provider has available quota to create missing bridge for configuration %s",
                              bridgeconf.id)
    logging.debug("Created %s bridges", created)
    return created


def deprecate_bridges(bridgeconf: BridgeConf, count: int, reason: str = "redundant") -> int:
    logging.debug("Deprecating %s bridges (%s) for configuration %s", count, reason, bridgeconf.id)
    deprecated = 0
    active_conf_bridges = iter(Bridge.query.filter(
        Bridge.conf_id == bridgeconf.id,
        Bridge.deprecated.is_(None),
        Bridge.destroyed.is_(None),
    ).all())
    while deprecated < count:
        logging.debug("Deprecating bridge %s for configuration %s", deprecated + 1, bridgeconf.id)
        bridge = next(active_conf_bridges)
        logging.debug("Bridge %r", bridge)
        bridge.deprecate(reason=reason)
        deprecated += 1
    return deprecated


class BridgeMetaAutomation(BaseAutomation):
    short_name = "bridge_meta"
    description = "Housekeeping for bridges"
    frequency = 1

    def automate(self, full: bool = False) -> Tuple[bool, str]:
        # Destroy expired bridges
        deprecated_bridges: List[Bridge] = Bridge.query.filter(
            Bridge.destroyed.is_(None),
            Bridge.deprecated.is_not(None),
        ).all()
        logging.debug("Found %s deprecated bridges", len(deprecated_bridges))
        for bridge in deprecated_bridges:
            cutoff = datetime.datetime.utcnow() - datetime.timedelta(hours=bridge.conf.expiry_hours)
            if bridge.deprecated < cutoff:
                logging.debug("Destroying expired bridge")
                bridge.destroy()
        # Deprecate orphaned bridges
        active_bridges = Bridge.query.filter(
            Bridge.deprecated.is_(None),
            Bridge.destroyed.is_(None),
        ).all()
        logging.debug("Found %s active bridges", len(active_bridges))
        for bridge in active_bridges:
            if bridge.conf.destroyed is not None:
                bridge.deprecate(reason="conf_destroyed")
        # Create new bridges
        activate_bridgeconfs = BridgeConf.query.filter(
            BridgeConf.destroyed.is_(None),
        ).all()
        logging.debug("Found %s active bridge configurations", len(activate_bridgeconfs))
        for bridgeconf in activate_bridgeconfs:
            active_conf_bridges = Bridge.query.filter(
                Bridge.conf_id == bridgeconf.id,
                Bridge.deprecated.is_(None),
                Bridge.destroyed.is_(None),
            ).all()
            total_conf_bridges = Bridge.query.filter(
                Bridge.conf_id == bridgeconf.id,
                Bridge.destroyed.is_(None),
            ).all()
            logging.debug("Generating new bridges for %s (active: %s, total: %s, target: %s, max: %s)",
                          bridgeconf.id,
                          len(active_conf_bridges),
                          len(total_conf_bridges),
                          bridgeconf.target_number,
                          bridgeconf.max_number
                          )
            missing = min(
                bridgeconf.target_number - len(active_conf_bridges),
                bridgeconf.max_number - len(total_conf_bridges))
            if missing > 0:
                create_bridges(bridgeconf, missing)
            elif missing < 0:
                deprecate_bridges(bridgeconf, 0 - missing)
        db.session.commit()
        return True, ""