"""Application entry point: wires slices, cross-cutting request rules, and JSON error handling."""

import logging

import psycopg2.errors
from flask import Flask, Response, g, jsonify, request
from flask.typing import ResponseReturnValue
from werkzeug.exceptions import HTTPException

import auth
import books
import db
import notes
from validation import ApiError

log = logging.getLogger(__name__)
MUTATING_METHODS = {"POST", "PUT", "PATCH", "DELETE"}


def create_app() -> Flask:
    logging.basicConfig(
        level=logging.INFO, format="%(asctime)s %(levelname)s %(name)s: %(message)s"
    )
    app = Flask(__name__)
    app.config["MAX_CONTENT_LENGTH"] = 1024 * 1024
    db.init_app(app)
    auth.init_app(app)
    app.register_blueprint(books.bp)
    app.register_blueprint(notes.bp)

    @app.get("/api/health")
    @auth.allow_anonymous
    def health() -> ResponseReturnValue:
        return {"status": "ok"}

    @app.before_request
    def require_json_for_mutations() -> None:
        if request.method in MUTATING_METHODS and not request.is_json:
            raise ApiError(
                400, "Request body must be JSON with Content-Type: application/json"
            )

    @app.after_request
    def log_request(response: Response) -> Response:
        log.info(
            "%s %s -> %s user=%s",
            request.method,
            request.path,
            response.status_code,
            g.get("user_id"),
        )
        return response

    @app.errorhandler(ApiError)
    def handle_api_error(error: ApiError) -> ResponseReturnValue:
        body = {"error": error.message}
        if error.field:
            body["field"] = error.field
        return jsonify(body), error.status

    @app.errorhandler(HTTPException)
    def handle_http_error(error: HTTPException) -> ResponseReturnValue:
        return jsonify(error=error.description), error.code or 500

    @app.errorhandler(psycopg2.errors.CheckViolation)
    def handle_check_violation(
        error: psycopg2.errors.CheckViolation,
    ) -> ResponseReturnValue:
        return (
            jsonify(
                error=f"Value breaks data rule '{error.diag.constraint_name}'; correct it and retry"
            ),
            400,
        )

    @app.errorhandler(Exception)
    def handle_unexpected(_error: Exception) -> ResponseReturnValue:
        log.exception("Unhandled error on %s %s", request.method, request.path)
        return jsonify(error="Unexpected server error"), 500

    return app


if __name__ == "__main__":
    create_app().run(host="127.0.0.1", port=5000)