import os
from datetime import datetime

import pymysql
import requests

CE_ENDPOINT = os.environ["CE_ENDPOINT"]
CE_DB_HOST = os.environ["CE_DB_HOST"]
CE_DB_PORT = 4000
CE_DB_USER = os.environ["CE_DB_USER"]
CE_DB_PASSWD = os.environ["CE_DB_PASSWD"]
CE_DB_NAME = "diagnose-rule-stats"


def lambda_handler(event, context):
    if context.get_remaining_time_in_millis() < 60000:
        raise ValueError("the lambda function's timeout property should be configured at least 60s")

    _end = int(datetime.now().timestamp())
    _start = _end - 600

    try:
        trigger_stats = calculate_trigger_stats(_start, _end)
        write_trigger_stats_to_db(trigger_stats)
    except Exception as e:
        return {
            "code": 500,
            "error": e,
        }
    return {"code": 200}


def query_api(uri, body=None):
    _url = "{}{}".format(CE_ENDPOINT, uri)
    if not body:
        return requests.get(_url).json()
    return requests.post(_url, json=body).json()


def calculate_trigger_stats(start, end):
    log_uri = "/tasks/log-diag?status=success&begin={}&end={}".format(start, end)
    log_resp = query_api(log_uri, {"data": {"abnormal": True}})
    metric_uri = "/tasks/metrics-advisor?status=success&begin={}&end={}".format(start, end)
    metric_resp = query_api(metric_uri, {"data": {"abnormal": True}})
    joint_resp = log_resp + metric_resp

    stats = {}
    for _resp in joint_resp:
        # validate responses
        _data = _resp["data"]
        if _resp["status"] != "success" or not _data["abnormal"]:
            continue

        # convert timestamp to 1min steps
        _cts = _resp["created_at"]
        _ts = _cts - (_cts % 60)

        for _advice in _resp["data"]["advice"]:
            _key = "{}-{}".format(_ts, _advice["id"])
            try:
                stats[_key]["cnt"] += 1
            except KeyError:
                stats[_key] = {"id": _advice["id"], "time": _ts, "cnt": 1}

    return stats


def write_trigger_stats_to_db(stats):
    conn = pymysql.connect(
        host=CE_DB_HOST,
        port=CE_DB_PORT,
        user=CE_DB_USER,
        password=CE_DB_PASSWD,
        database=CE_DB_NAME,
        charset="utf8mb4",
        cursorclass=pymysql.cursors.DictCursor,
    )
    with conn:
        with conn.cursor() as cursor:
            for stat in stats.values():
                _ts = datetime.fromtimestamp(stat["time"]).strftime("%Y-%m-%d %H:%M:%S")
                sql = "REPLACE INTO `rule_trigger_details` (rule_id, ts, alert_cnt) VALUES ('{}', '{}', '{}')".format(
                    stat["id"],
                    _ts,
                    stat["cnt"],
                )
                try:
                    cursor.execute(sql)
                except pymysql.IntegrityError:  # skip exist rows
                    continue

        # connection is not autocommit by default. So you must commit to save
        # your changes.
        conn.commit()