from utils.config_validate import ConfigError, require, require_schema
from components.sud import Sud

# The only part of a sud.json document's shape that's fixed regardless of
# content - same declarative mechanism validate_temp_ctrl() uses for
# config.json's TempCtrl section (see config_validate.py's require_schema()).
# Everything else about a schedule (how many steps, which fields each one
# overrides vs. inherits from default.step, whether a step needs ramp.rate
# at all) depends on the document's own content, not just its shape, so it
# can't be expressed as a static schema - handled by the step loop below
# instead, still built on the same require()/ConfigError primitives.
SUD_SCHEMA = {
    'steps': list,
}


def validate_sud(data):
    """Fail-fast structural check for a sud.json document - same rationale
    as config_validate.py's validate_temp_ctrl(): a malformed field here
    doesn't surface until deep inside a run, or worse, during
    SudForecastEstimator's very first Load-time simulation (tasks/sud.py,
    components/sud_forecast.py and scripts/demos/sud/demo_sud.py all read
    ramp['rate'] directly, no .get() fallback, the moment any step actually
    sets its own 'temperature') - as a bare KeyError with no indication of
    which schedule step or field is wrong.

    Reuses Sud._parse_data() itself (rather than re-implementing default-
    merging/step-building) so what's checked here can never drift from what
    actually gets parsed at runtime."""
    require_schema(data, SUD_SCHEMA)
    if not data['steps']:
        raise ConfigError("'steps' must be a non-empty list")

    try:
        schedule = Sud._parse_data(data)[2]
    except (KeyError, TypeError, AttributeError) as e:
        raise ConfigError("malformed sud document: {}".format(e))

    for step in schedule:
        if step['temperature'] is None:
            continue
        try:
            require(step, 'ramp.rate', type=(int, float))
        except ConfigError as e:
            raise ConfigError("step {} ({}): {}".format(step['number'], step.get('descr'), e))