import os

from sqlalchemy.orm import Session as DBSession

from app.db.models import AppSetting

# GUIから編集可能な環境変数の許可リスト。ここに無いキーは save()/clear() で拒否する。
CONFIGURABLE_KEYS = [
    "OPENAI_API_KEY",
    "ANTHROPIC_API_KEY",
    "AWS_ACCESS_KEY_ID",
    "AWS_SECRET_ACCESS_KEY",
    "AWS_SESSION_TOKEN",
    "AWS_BEARER_TOKEN_BEDROCK",
    "AWS_REGION_NAME",
    "OLLAMA_API_BASE",
    "TAVILY_API_KEY",
    "LOCAL_KB_EMBEDDING_MODEL",
]

# .env由来の起動時の値のスナップショット。clear() で戻す先として使う。
_env_defaults: dict[str, str | None] = {}
_snapshot_taken = False


def _ensure_snapshot() -> None:
    global _snapshot_taken
    if _snapshot_taken:
        return
    for key in CONFIGURABLE_KEYS:
        _env_defaults[key] = os.environ.get(key)
    _snapshot_taken = True


def _mask(value: str) -> str:
    if len(value) <= 4:
        return "••••"
    return f"••••{value[-4:]}"


def load_into_env(db: DBSession) -> None:
    """DBに保存済みの値をos.environに適用する。起動時に一度呼ぶ。"""
    _ensure_snapshot()
    for row in db.query(AppSetting).all():
        if row.key in CONFIGURABLE_KEYS:
            os.environ[row.key] = row.value


def list_masked(db: DBSession) -> list[dict]:
    _ensure_snapshot()
    saved = {row.key: row.value for row in db.query(AppSetting).all()}
    result = []
    for key in CONFIGURABLE_KEYS:
        current = os.environ.get(key)
        result.append({
            "key": key,
            "is_set": bool(current),
            "masked": _mask(current) if current else None,
            "overridden": key in saved,
        })
    return result


def save(db: DBSession, key: str, value: str) -> None:
    if key not in CONFIGURABLE_KEYS:
        raise ValueError(f"Unknown setting key: {key}")
    _ensure_snapshot()
    row = db.get(AppSetting, key)
    if row:
        row.value = value
    else:
        db.add(AppSetting(key=key, value=value))
    db.commit()
    os.environ[key] = value


def clear(db: DBSession, key: str) -> None:
    if key not in CONFIGURABLE_KEYS:
        raise ValueError(f"Unknown setting key: {key}")
    _ensure_snapshot()
    row = db.get(AppSetting, key)
    if row:
        db.delete(row)
        db.commit()
    original = _env_defaults.get(key)
    if original is None:
        os.environ.pop(key, None)
    else:
        os.environ[key] = original