import datetime
import decimal
import json
import uuid

from plain.utils.duration import duration_iso_string
from plain.utils.functional import Promise
from plain.utils.timezone import is_aware


class PlainJSONEncoder(json.JSONEncoder):
    """
    JSONEncoder subclass that knows how to encode date/time, decimal types, and
    UUIDs.
    """

    def default(self, o):
        # See "Date Time String Format" in the ECMA-262 specification.
        if isinstance(o, datetime.datetime):
            r = o.isoformat()
            if o.microsecond:
                r = r[:23] + r[26:]
            if r.endswith("+00:00"):
                r = r.removesuffix("+00:00") + "Z"
            return r
        elif isinstance(o, datetime.date):
            return o.isoformat()
        elif isinstance(o, datetime.time):
            if is_aware(o):
                raise ValueError("JSON can't represent timezone-aware times.")
            r = o.isoformat()
            if o.microsecond:
                r = r[:12]
            return r
        elif isinstance(o, datetime.timedelta):
            return duration_iso_string(o)
        elif isinstance(o, decimal.Decimal | uuid.UUID | Promise):
            return str(o)
        else:
            return super().default(o)