"""Clinical modules config (`config/modules.yaml`, ADR-001) and scale scheduling.

Shared by the dialog engine (lane A: start screening, daily question) and the scheduler (lane B: due scales).
"""

from datetime import date
from functools import lru_cache
from pathlib import Path
from typing import Literal

import yaml
from pydantic import BaseModel, ConfigDict, Field

from app.config import get_settings

ModuleId = Literal["veteran", "depression", "family"]


class _Strict(BaseModel):
    model_config = ConfigDict(extra="forbid", frozen=True)


class ScheduleEntry(_Strict):
    scale: str
    every_days: int = Field(gt=0)
    from_day: int = 0
    until_day: int | None = None


class Threshold(_Strict):
    scale: str
    op: Literal[">=", ">"]
    value: int


class ModuleDef(_Strict):
    title: str
    start_scales: list[str]
    start_questions: list[str] = Field(default_factory=list)
    daily_question: str | None = None
    schedule: list[ScheduleEntry] = Field(default_factory=list)
    enables_depression_if: Threshold | None = None
    enhanced_monitoring_under_age: int | None = None


class CoreDef(_Strict):
    daily: list[str]
    silence_alert_days: int
    item9_followup: str


class ModulesConfig(_Strict):
    core: CoreDef
    modules: dict[ModuleId, ModuleDef]


@lru_cache
def load_modules(path: Path | None = None) -> ModulesConfig:
    path = path or get_settings().config_dir / "modules.yaml"
    return ModulesConfig.model_validate(yaml.safe_load(path.read_text(encoding="utf-8")))


def due_scales(
    modules: set[str], therapy_day: int, last_done: dict[str, date], today: date, config: ModulesConfig | None = None
) -> list[str]:
    """Scales due today for a patient: per enabled module, a scale is due if never done in its window or
    `every_days` have passed since it was last completed. Deduplicated, in config order."""
    cfg = config or load_modules()
    out: list[str] = []
    for mod_id, mod in cfg.modules.items():
        if mod_id not in modules:
            continue
        for e in mod.schedule:
            if therapy_day < e.from_day or (e.until_day is not None and therapy_day > e.until_day):
                continue
            last = last_done.get(e.scale)
            if (last is None or (today - last).days >= e.every_days) and e.scale not in out:
                out.append(e.scale)
    return out