"""

    AUTHOR:

        Khushal P Soonderji

    DATE:

        Tuesday, 8th Oct., 2024

    OBJECTIVE:

        This is the central location for the Quart module.
        We define the app here, and import and attach all blueprints here.

    REFERENCES:

        N/A

    DOWNLOADS:

        N/A

"""


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                                   IMPORT                                                      ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


# To make sibling directories accessible for imports:
import sys
sys.path.append(".")
sys.path.append("..")

# For system level activities:
import gc
import os
import psutil

# For using Quart:
from quart import Quart, request, current_app, redirect
from quart_cors import cors

# Common:
from shared import constants

# My utils:
from utils_v2.string import json
from utils_v2.api import async_quart
from utils_v2.date_time import date_time
from utils_v2.database.async_mongo_v2 import AsyncMongo
from utils_v2.cache.async_redis_cache_v3 import AsyncRedisCache
from utils_v2.api.async_quart import (
    set_api_version,
    read_input,
    log_request_to_mongo,
    should_not_be_under_maintenance,
    only_whitelisted_ips,
    limit_rate,
    validate_input,
    handle_cancelled_request
)

# For debugging:
from icecream import IceCreamDebugger

# Controllers:
from controllers.servers.server import CoreServerController

# All the blueprints:
from api_v2.blueprints.cred_and_data.blueprint import cred_and_data_bp
from api_v2.blueprints.logs.blueprint import logs_bp
from api_v2.blueprints.otp.blueprint import otp_bp
from api_v2.blueprints.servers.blueprint import servers_bp


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                           MACROS / ONE-TIME INIT                                              ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


# Quart related:
MODULE_BASE = "internal"
APP_VERSION = "2.2.0"


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                                VARIABLES                                                      ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


# The Quart app:
app = Quart(__name__)
app = cors(app)
app.register_blueprint(cred_and_data_bp, url_prefix = f"/{MODULE_BASE}")
app.register_blueprint(logs_bp, url_prefix = f"/{MODULE_BASE}/logs")
app.register_blueprint(otp_bp, url_prefix = f"/{MODULE_BASE}/otp")
app.register_blueprint(servers_bp, url_prefix = f"/{MODULE_BASE}/servers")


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                                  FUNCTIONS                                                    ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


@app.before_serving
@set_api_version(api_version = APP_VERSION)
@log_request_to_mongo(
    attr_name = "mongo",
    log_type = MODULE_BASE,
    operation = "apiStart",
    log_input = True,
    log_output = True
)
async def app_startup(**kwargs):

    """
    To initialize the variables that you would like to use in this module.
    WARNING: ALL VARIABLES WILL BE INITIALIZED 'n' NUMBER OF TIMES, WHERE 'n' IS THE COUNT OF WORKERS DEPLOYED.
    SO, IF YOU WANT TO CONNECT TO A DATABASE AND YOU ALLOW A POOL-SIZE OF 10 AND IF YOU DEPLOY 4 WORKERS, YOU WILL END
    UP WITH 40 CONNECTIONS TO THE DATABASE.
    :return: None.
    """

    # ┳  • •  ┓•
    # ┃┏┓┓╋┓┏┓┃┓┓┏┓
    # ┻┛┗┗┗┗┗┻┗┗┗┗

    # Safe-halt mechanism for upgrades (for a single-worker run):
    current_app.is_under_maintenance = False

    # ┳┓  ┓       •
    # ┃┃┏┓┣┓┓┏┏┓┏┓┓┏┓┏┓
    # ┻┛┗ ┗┛┗┻┗┫┗┫┗┛┗┗┫
    #          ┛ ┛    ┛

    # Debugging:
    enable_debugging = True if os.environ["DEBUG"].strip().lower() == "true" else False
    current_app.printer = IceCreamDebugger(prefix = f"{MODULE_BASE} (Q) | ", includeContext = True)
    if not enable_debugging: current_app.printer.disable()
    current_app.printer("initializing worker.")

    # ┳┳┓        ┳┓┳┓
    # ┃┃┃┏┓┏┓┏┓┏┓┃┃┣┫
    # ┛ ┗┗┛┛┗┗┫┗┛┻┛┻┛
    #         ┛

    # To connect to Mongo:
    current_app.mongo = AsyncMongo(
        connection_string = constants.MONGO_DATA_CONNECTION_STRING,
        database_name = constants.MONGO_DATA_DATABASE_NAME,
        max_connections = 10,
        debug = True,
        debug_only_errors = True
    )
    await current_app.mongo.connect()

    current_app.logs_mongo = current_app.mongo

    current_app.printer("MongoDB ready.")

    # ┏┓     ┓       ┓  ┳┓
    # ┃ ┏┓┏┓┏┫  ┏┓┏┓┏┫  ┃┃┏┓╋┏┓
    # ┗┛┛ ┗ ┗┻  ┗┻┛┗┗┻  ┻┛┗┻┗┗┻

    # Get the script data:
    script_id = os.environ["SCRIPT_ID"]
    script_cred = (await current_app.mongo.find_one(
        collection = "_scriptCred",
        filter = {"scriptId": script_id}
    ))["content"]
    current_app.script_data = (await current_app.mongo.find_one(
        collection = "_scriptData",
        filter = {"scriptId": script_id}
    ))["content"]

    current_app.printer("Cred and Data ready.")

    # ┳┓   ┓•   ┏┓   ┓
    # ┣┫┏┓┏┫┓┏  ┃ ┏┓┏┣┓┏┓
    # ┛┗┗ ┗┻┗┛  ┗┛┗┻┗┛┗┗

    current_app.otp_redis = AsyncRedisCache(
        connection_string = script_cred["redisCache"]["general"]["sentinelJson"],
        debug = enable_debugging,
        debug_prefix = "OTP Cache | "
    )

    current_app.printer("Redis ready.")

    # ┏┓         ┓┓
    # ┃ ┏┓┏┓╋┏┓┏┓┃┃┏┓┏┓┏
    # ┗┛┗┛┛┗┗┛ ┗┛┗┗┗ ┛ ┛

    current_app.server_controller = CoreServerController()

    current_app.printer("Controllers ready.")

    # ┳┳┓•
    # ┃┃┃┓┏┏
    # ┛ ┗┗┛┗•

    # Pick the important stuff:
    current_app.whitelisted_ips = current_app.script_data["whitelistedIps"]

    # Done here!
    print("Worker ready!")


# ---------------------------------------------------------------------------------------------------------------------


@app.after_serving
@set_api_version(api_version = APP_VERSION)
@log_request_to_mongo(
    attr_name = "mongo",
    log_type = MODULE_BASE,
    operation = "apiStop",
    log_input = True,
    log_output = True
)
async def app_shutdown(**kwargs):

    """
    This is called when "app.shutdown()" is called.
    :return: None.
    """

    message = "Shutting down..."
    current_app.printer(message)


# ---------------------------------------------------------------------------------------------------------------------


@app.before_request
async def enforce_https():

    """
    Here we enforce HTTPS (secure) requests and effectively reject unsecure requests. We make exemptions for local
    network requests for regular testing.
    :return: A redirect to the secure version if the incoming request is not secure.
    """

    # If the connection is not secure:
    if request.scheme != "https":

        # Check if it is a local IP. If not, redirect:
        exempt_ips = ["0.0.0.0", "127.0.0.1"]
        if not (
            request.remote_addr.startswith("192.168.") or
            request.remote_addr in exempt_ips
        ): return redirect(request.url.replace("http", "https"))


# ---------------------------------------------------------------------------------------------------------------------


@app.route(f"/", methods = ["GET", "POST"])
@app.route(f"/{MODULE_BASE}", methods = ["GET", "POST"])
async def root():

    """
    To check if the service is running or not.
    Use this to monitor the service from your "watchman" script.
    :return: only "ok"
    """

    return "ok"


# ---------------------------------------------------------------------------------------------------------------------


@app.route(f"/metrics/memory", methods = ["GET", "POST"])
@app.route(f"/{MODULE_BASE}/metrics/memory", methods = ["GET", "POST"])
async def metrics():

    """
    TO measure the metrics of the app.
    :return: A JSON of the metrics.
    """

    # Figure pout the parent process.
    # This is important for multi-worker environments:
    parent_pid = os.getppid()
    parent_process = psutil.Process(parent_pid)
    parent_mem_info = parent_process.memory_info()

    # Figure out all the children of the parent process:
    child_pids = [child.pid for child in parent_process.children()]
    child_processes = [psutil.Process(child_pid) for child_pid in child_pids]
    child_stats = []
    for pid, process in zip(child_pids, child_processes):
        mem_info = process.memory_info()
        child_stats.append({
            "pid": pid,
            "mem": round(mem_info.rss / (1024 ** 2), 2)
        })

    # Construct the response:
    metrics_json = {
        "parent": {
            "pid": parent_pid,
            "mem": round(parent_mem_info.rss / (1024 ** 2), 2)
        },
        "children": child_stats,
        "unit": {
            "mem": "MB"
        },
        "ts": date_time.get_current_ist_date_time(as_string = True)
    }

    # Done here:
    return metrics_json


# ---------------------------------------------------------------------------------------------------------------------


@app.route(f"/{MODULE_BASE}/debug/<action>", methods = ["POST", "GET"])
async def change_debug(action):

    """
    Enable or disable debugging for the entire microservice.
    WARNING: NOT RECOMMENDED FOR MULTI-WORKER DEPLOYMENTS.
    :param action: "enable" to allow debugging on the terminal, or "disable".
    :return: "enabled"/"disabled" if successful, else "ok"
    """

    # Enable or disable debugging only if the password matches:
    action = action.lower()
    if action == "enable": current_app.printer.enable()
    elif action == "disable": current_app.printer.disable()
    return "ok"


# ---------------------------------------------------------------------------------------------------------------------


@app.route(f"/{MODULE_BASE}/maintenance/<action>", methods = ["POST", "GET"])
async def change_maintenance(action):

    """
    Enable or disable debugging for the entire microservice.
    WARNING: NOT RECOMMENDED FOR MULTI-WORKER DEPLOYMENTS.
    :param action: "enable" to stop taking new requests on the API, or "disable".
    :return: "enabled"/"disabled" if successful, else "ok"
    """

    # Enable or disable debugging only if the password matches:
    action = action.lower()
    if action == "enable":
        current_app.is_under_maintenance = True
        os.environ["IS_UNDER_MAINTENANCE"] = "True"
    elif action == "disable":
        current_app.is_under_maintenance = False
        os.environ["IS_UNDER_MAINTENANCE"] = "False"
    return "ok"


#   *****************************************************************************************************************
#  *****                                                                                                          ****
# ***                                               MAIN PROGRAM                                                    ***
#  *****                                                                                                          ****
#   *****************************************************************************************************************


if __name__ == "__main__":

    # To get args from the terminal:
    import argparse

    # To run the ASGI:
    import uvicorn
    from multiprocessing import freeze_support

    # Get the config from the command-line:
    parser = argparse.ArgumentParser(description = f"Microservice for '{MODULE_BASE}' API.")
    parser.add_argument(
        "--workers",
        type = int,
        help = "The no. of threads to spin up for this instance!",
        default = 2
    )
    parser.add_argument(
        "--host",
        type = str,
        help = "The host for the app. e.g.: '0.0.0.0' or '127.0.0.1'.",
        default = "127.0.0.1"
    )
    parser.add_argument(
        "--port",
        type = int,
        help = "The port no. to bind the app to.",
        default = 8080
    )
    parser.add_argument(
        "--script-id",
        type = str,
        help = "The id of this script (will affect the loaded config)."
    )
    parser.add_argument(
        "--debug",
        action = "store_true",
        help = "Whether, or not, you want to see debugging messages in the terminal.",
        default = False
    )
    args = parser.parse_args()

    # Note down the config;
    os.environ["SCRIPT_ID"] = args.script_id
    os.environ["DEBUG"] = str(args.debug)

    # Run the gateway:
    freeze_support()
    uvicorn.run(
        app = "main:app",
        workers = args.workers,
        host = args.host,
        port = args.port
    )