"""
Ziel-Module für CSV-Import: Tabellen-Felder, Pflichtfelder, Duplikat-Strategie (Issue #21).

Hinweis: blood_pressure nutzt in der DB measured_at; Logik-Felder measured_date + measured_time
werden im Executor zu measured_at zusammengefügt (Phase Import-Executor).

Activity: date kann aus start_time (ISO-Datetime) abgeleitet werden, wenn nur start_time gesetzt ist.
"""

from __future__ import annotations

from typing import Any, Dict, cast

MODULE_DEFINITIONS: Dict[str, Dict[str, Any]] = {
    "nutrition": {
        "table": "nutrition_log",
        "fields": {
            "date": {"type": "date", "required": True},
            "kcal": {"type": "float", "required": False},
            "protein_g": {"type": "float", "required": False, "min": 0},
            "fat_g": {"type": "float", "required": False, "min": 0},
            "carbs_g": {"type": "float", "required": False, "min": 0},
        },
        "duplicate_key": ["profile_id", "date"],
        "duplicate_strategy": "update",
    },
    "activity": {
        "table": "activity_log",
        "fields": {
            "date": {"type": "date", "required": True},
            "start_time": {"type": "time", "required": False},
            "end_time": {"type": "time", "required": False},
            "activity_type": {"type": "string", "required": True},
            "duration_min": {"type": "float", "required": False, "min": 0},
            "kcal_active": {"type": "float", "required": False},
            "distance_km": {"type": "float", "required": False},
            "hr_avg": {"type": "float", "required": False, "min": 30, "max": 220},
        },
        "derive_date_from_datetime_field": "start_time",
        "duplicate_key": ["profile_id", "date", "start_time"],
        "duplicate_strategy": "update",
    },
    "blood_pressure": {
        "table": "blood_pressure_log",
        "fields": {
            "measured_date": {"type": "date", "required": True},
            "measured_time": {"type": "time", "required": True},
            "systolic": {"type": "int", "required": True},
            "diastolic": {"type": "int", "required": True},
            "pulse": {"type": "int", "required": False},
        },
        "logical_to_db": "blood_pressure_composite_measured_at",
        "duplicate_key": ["profile_id", "measured_at"],
        "duplicate_strategy": "update",
    },
    "weight": {
        "table": "weight_log",
        "fields": {
            "date": {"type": "date", "required": True},
            "weight": {"type": "float", "required": True, "min": 20, "max": 400},
            "note": {"type": "string", "required": False, "max_length": 2000},
        },
        "duplicate_key": ["profile_id", "date"],
        "duplicate_strategy": "update",
    },
}


def get_module_definition(module: str) -> Dict[str, Any] | None:
    return MODULE_DEFINITIONS.get(module)


def list_modules() -> list[str]:
    return sorted(MODULE_DEFINITIONS.keys())


def validate_field_mappings(module: str, field_mappings: dict) -> None:
    """Wirft ValueError bei unbekanntem Modul oder unbekanntem DB-Feld."""
    mod = get_module_definition(module)
    if not mod:
        raise ValueError(f"Unbekanntes Modul: {module}")
    fields = cast(dict, mod["fields"])
    allowed = set(fields.keys())
    for _csv_col, db_field in field_mappings.items():
        if db_field in ("", None, "-"):
            continue
        if db_field not in allowed:
            raise ValueError(f"Ungültiges Zielfeld '{db_field}' für Modul '{module}'")