"""Generic routing utilities."""
import logging
from json.decoder import JSONDecodeError

from flask import (flash,
                   url_for,
                   request,
                   redirect,
                   render_template,
                   current_app as app)

from gn_libs.mysqldb import database_connection

from uploader.datautils import base64_encode_dict, base64_decode_to_dict
from uploader.population.models import (populations_by_species,
                                        population_by_species_and_id)

logger = logging.getLogger(__name__)

def generic_select_population(
        # pylint: disable=[too-many-arguments, too-many-positional-arguments]
        species: dict,
        template: str,
        population_id: str,
        back_to: str,
        forward_to: str,
        activelink: str,
        error_message: str = "No such population found!"
):
    """Handles common flow for 'select population' step."""
    with database_connection(app.config["SQL_URI"]) as conn:
        if not bool(population_id):
            return render_template(
                template,
                species=species,
                populations=populations_by_species(conn, species["SpeciesId"]),
                activelink=activelink)

        if population_id == "CREATE-POPULATION":
            return redirect(url_for(
                "species.populations.create_population",
                species_id=species["SpeciesId"],
                return_to=forward_to))

        population = population_by_species_and_id(
            conn, species["SpeciesId"], int(population_id))
        if not bool(population):
            flash(error_message, "alert-danger")
            return redirect(url_for(back_to, species_id=species["SpeciesId"]))

        return redirect(url_for(forward_to,
                                species_id=species["SpeciesId"],
                                population_id=population["Id"]))


def redirect_to_next(default: dict):
    """Redirect to the next uri if specified, else redirect to default."""
    assert "uri" in default, "You must provide at least the 'uri' value."
    try:
        next_page = base64_decode_to_dict(request.args.get("next"))
        _uri = next_page["uri"]
        next_page.pop("uri")
        return redirect(url_for(_uri, **next_page))
    except (TypeError, JSONDecodeError) as _err:
        logger.debug("We could not decode the next value '%s'",
                     next_page,
                     exc_info=True)

    return redirect(url_for(
        default["uri"],
        **{key:value for key,value in default.items() if key != "uri"}))


def build_next_argument(uri: str, **kwargs) -> str:
    """Build the `next` URI argument from provided details."""
    dumps_keywords = (
        "skipkeys", "ensure_ascii", "check_circular", "allow_nan", "cls",
        "indent", "separators", "default", "sort_keys")
    return base64_encode_dict(
        {
            "uri": uri,
            **{
                key: val for key,val in kwargs.items()
                if key not in dumps_keywords
            }
        },
        **{
            key: val for key,val in kwargs.items()
            if key in dumps_keywords
        })