from __future__ import annotations

import logging
from logging.handlers import RotatingFileHandler
import os
import sys
import threading

from flask import Flask, Response, abort, jsonify, render_template, url_for
from werkzeug.exceptions import HTTPException

from .collector import Collector
from .config import Config
from .netatmo import NetatmoClient
from .rrd import ALIASES, PERIODS, RRD_ERROR, RRDStore, SCHEMAS


class PrefixMiddleware:
    """Mount a WSGI application below a fixed URL path."""

    def __init__(self, application, prefix: str):
        self.application = application
        self.prefix = prefix

    def __call__(self, environ, start_response):
        path = environ.get("PATH_INFO", "")
        if path == self.prefix or path.startswith(f"{self.prefix}/"):
            environ["SCRIPT_NAME"] = environ.get("SCRIPT_NAME", "") + self.prefix
            environ["PATH_INFO"] = path[len(self.prefix):] or "/"
            return self.application(environ, start_response)
        start_response("404 Not Found", [("Content-Type", "text/plain; charset=utf-8")])
        return [b"Not Found\n"]


def configure_logging(app: Flask) -> None:
    log_path = app.config["LOG_FILE"]
    log_path.parent.mkdir(parents=True, exist_ok=True)
    handler = RotatingFileHandler(
        log_path,
        maxBytes=app.config["LOG_MAX_BYTES"],
        backupCount=app.config["LOG_BACKUP_COUNT"],
        encoding="utf-8",
    )
    handler.setFormatter(logging.Formatter(
        "%(asctime)s %(levelname)s %(name)s [%(threadName)s] %(message)s"
    ))
    root = logging.getLogger()
    root.setLevel(app.config["LOG_LEVEL"])
    # Avoid duplicate handlers when an app factory is called repeatedly in tests.
    target = str(log_path)
    if not any(
        isinstance(item, RotatingFileHandler)
        and getattr(item, "baseFilename", None) == target
        for item in root.handlers
    ):
        root.addHandler(handler)
    else:
        handler.close()

    def uncaught_exception(exception_type, exception, traceback):
        if issubclass(exception_type, KeyboardInterrupt):
            return sys.__excepthook__(exception_type, exception, traceback)
        logging.getLogger("netatmo_service.uncaught").critical(
            "Uncaught Python exception", exc_info=(exception_type, exception, traceback)
        )

    def uncaught_thread_exception(arguments):
        logging.getLogger("netatmo_service.uncaught").critical(
            "Uncaught exception in thread %s",
            arguments.thread.name if arguments.thread else "unknown",
            exc_info=(arguments.exc_type, arguments.exc_value, arguments.exc_traceback),
        )

    sys.excepthook = uncaught_exception
    threading.excepthook = uncaught_thread_exception


def create_app(test_config: dict | None = None) -> Flask:
    app = Flask(__name__)
    app.config.from_object(Config)
    if test_config:
        app.config.update(test_config)

    prefix = app.config["URL_PREFIX"]
    app.config["APPLICATION_ROOT"] = prefix or "/"
    if prefix:
        app.wsgi_app = PrefixMiddleware(app.wsgi_app, prefix)

    configure_logging(app)
    app.logger.info("Starting GetNetatmoData v2 (URL prefix=%s)", prefix or "/")
    store = app.config.get("RRD_STORE") or RRDStore(
        app.config["RRD_FOLDER"], app.config["GRAPH_WIDTH"], app.config["GRAPH_HEIGHT"]
    )
    store.ensure_all()
    client = app.config.get("NETATMO_CLIENT") or NetatmoClient(app.config)
    names = {key: app.config[f"MODULE_{key.upper()}"] for key in SCHEMAS}
    collector = Collector(client, store, names, app.config["POLL_INTERVAL"])
    app.extensions["rrd_store"] = store
    app.extensions["netatmo_collector"] = collector

    # Flask's debug reloader imports twice. Only its serving child starts a poller.
    should_start = app.config["START_COLLECTOR"] and client.configured
    if should_start and (not app.debug or os.environ.get("WERKZEUG_RUN_MAIN") == "true"):
        collector.start()
    elif app.config["START_COLLECTOR"] and not client.configured:
        app.logger.warning("Collector disabled: configure NETATMO_ACCESS_TOKEN or OAuth refresh credentials")

    @app.get("/")
    def dashboard():
        return render_template(
            "dashboard.html",
            rrd_names=list(SCHEMAS),
            periods=list(PERIODS),
            graph_url_template=url_for("graph", rrd_name="__name__", period="__period__"),
        )

    @app.get("/health")
    def health():
        return jsonify(status="ok", collector_configured=client.configured)

    @app.errorhandler(Exception)
    def unexpected_error(error):
        if isinstance(error, HTTPException):
            return error
        app.logger.exception("Unhandled Flask request error")
        return jsonify(error="Internal server error"), 500

    @app.get("/last/<rrd_name>/<data_point>")
    def last(rrd_name: str, data_point: str):
        try:
            return jsonify(store.last(rrd_name.lower(), data_point.lower()))
        except KeyError:
            abort(404, description="Unknown RRD or data point")
        except (OSError, RuntimeError, RRD_ERROR):
            app.logger.exception("Could not read RRD")
            abort(503, description="RRD data is unavailable")

    @app.get("/graph/<rrd_name>/<period>")
    def graph(rrd_name: str, period: str):
        try:
            image = store.graph(rrd_name.lower(), ALIASES.get(period.lower(), period.lower()))
            return Response(image, mimetype="image/png", headers={"Cache-Control": "no-cache, max-age=0"})
        except KeyError:
            abort(404, description="Unknown RRD or period")
        except (OSError, RuntimeError, RRD_ERROR):
            app.logger.exception("Could not render graph")
            abort(503, description="RRD graph is unavailable")

    # Compatibility with the compact form requested as /graph/[rrdname][period].
    @app.get("/graph/<rrd_and_period>")
    def compact_graph(rrd_and_period: str):
        for name in SCHEMAS:
            if rrd_and_period.startswith(name):
                return graph(name, rrd_and_period[len(name):].lstrip("-_"))
        abort(404, description="Unknown RRD or period")

    @app.cli.command("collect-now")
    def collect_now():
        """Fetch Netatmo and update every RRD immediately."""
        count = collector.collect_once()
        print(f"Updated {count} RRDs")

    return app