"""器谱应用服务：设备配对、逐项授契、撤回与可用性裁决。

铁律（PRD §8.3）：器谱属于镜域、逐项授契；撤回立即生效；
失联设备只允许安全自治与输入暂存（不产生本地人物副本）。
"""

from __future__ import annotations

import json

from sqlalchemy import select

from app.core.errors import AppError
from app.core.time import utc_now
from app.db.session import AsyncSessionLocal
from app.domains import one_qi
from app.domains.tianzai.models import Device, DeviceGrant

# 器谱能力键（可授契面；新增能力必须显式登记于此）
GRANTABLE = {
    "notifications", "file_dialog", "voice_input",
    "camera", "screen", "location", "local_search",
}


async def pair_device(*, owner_scope: str, kind: str, name: str, key_fingerprint: str) -> dict:
    """配对设备（一次配对；指纹登记后续凭证验签依据）。"""
    async with AsyncSessionLocal() as session:
        device = Device(
            owner_scope=owner_scope, kind=kind or "desktop_shell",
            name=name, key_fingerprint=key_fingerprint,
        )
        session.add(device)
        await session.commit()
        session.expunge(device)
        return _device_dict(device)


async def list_devices(owner_scope: str) -> list[dict]:
    async with AsyncSessionLocal() as session:
        rows = (
            await session.execute(
                select(Device).where(Device.owner_scope == owner_scope)
                .order_by(Device.created_at.desc())
            )
        ).scalars().all()
        return [_device_dict(r) for r in rows]


async def revoke_device(device_id: str, owner_scope: str) -> dict:
    """撤销设备：立即生效（全部授契随之失效）。"""
    await _owned_device(device_id, owner_scope)
    async with AsyncSessionLocal() as session:
        device = await session.get(Device, device_id)
        device.status = "revoked"
        grants = (
            await session.execute(
                select(DeviceGrant).where(DeviceGrant.device_id == device_id, DeviceGrant.status == "active")
            )
        ).scalars().all()
        now = utc_now()
        for g in grants:
            g.status = "revoked"
            g.revoked_at = now
        await session.commit()
    await one_qi.emit(
        "device.revoked", character_id=None,
        payload={"device_id": device_id}, source="tianzai",
    )
    return {"device_id": device_id, "status": "revoked", "grants_revoked": len(grants)}


async def grant(device_id: str, owner_scope: str, *, capability: str, scope: dict) -> dict:
    """逐项授契（能力键必须显式登记；设备撤销后不可再授）。"""
    if capability not in GRANTABLE:
        raise AppError(
            "invalid_request",
            f"未知器谱能力：{capability}（可授面：{sorted(GRANTABLE)}）",
        )
    await _owned_device(device_id, owner_scope)
    async with AsyncSessionLocal() as session:
        device = await session.get(Device, device_id)
        if device.status != "active":
            raise AppError("invalid_request", "设备已撤销，不可授契。", status_code=409)
        row = DeviceGrant(
            device_id=device_id, owner_scope=owner_scope,
            capability=capability, scope_json=json.dumps(scope or {}, ensure_ascii=False),
        )
        session.add(row)
        await session.commit()
        session.expunge(row)
        return _grant_dict(row)


async def revoke_grant(grant_id: str, owner_scope: str) -> dict:
    """撤回单项授契：立即生效。"""
    async with AsyncSessionLocal() as session:
        row = await session.get(DeviceGrant, grant_id)
        if row is None or row.owner_scope != owner_scope:
            raise AppError("not_found", "授契不存在。", status_code=404)
        row.status = "revoked"
        row.revoked_at = utc_now()
        await session.commit()
    return {"grant_id": grant_id, "status": "revoked", "effective": "immediate"}


async def assert_granted(device_id: str, owner_scope: str, capability: str) -> dict:
    """能力使用前置裁决：设备 active 且该能力授契 active（失联= revoked 同拒）。"""
    await _owned_device(device_id, owner_scope)
    async with AsyncSessionLocal() as session:
        device = await session.get(Device, device_id)
        if device.status != "active":
            raise AppError("invalid_request", "设备已撤销，能力不可用。", status_code=403)
        row = (
            await session.execute(
                select(DeviceGrant).where(
                    DeviceGrant.device_id == device_id,
                    DeviceGrant.capability == capability,
                    DeviceGrant.status == "active",
                )
            )
        ).scalars().first()
        if row is None:
            raise AppError(
                "invalid_request", f"能力 {capability} 未授契（器谱逐项授权）。", status_code=403
            )
        device.last_seen_at = utc_now()
        await session.commit()
        session.expunge(row)
        return _grant_dict(row)


async def list_grants(device_id: str, owner_scope: str) -> list[dict]:
    await _owned_device(device_id, owner_scope)
    async with AsyncSessionLocal() as session:
        rows = (
            await session.execute(
                select(DeviceGrant).where(DeviceGrant.device_id == device_id)
                .order_by(DeviceGrant.granted_at.desc())
            )
        ).scalars().all()
        return [_grant_dict(r) for r in rows]


async def _owned_device(device_id: str, owner_scope: str) -> None:
    async with AsyncSessionLocal() as session:
        device = await session.get(Device, device_id)
        if device is None or device.owner_scope != owner_scope:
            raise AppError("not_found", "设备不存在。", status_code=404)


def _device_dict(d: Device) -> dict:
    return {
        "id": d.id, "kind": d.kind, "name": d.name,
        "key_fingerprint": d.key_fingerprint, "status": d.status,
        "created_at": d.created_at.isoformat() if d.created_at else None,
        "last_seen_at": d.last_seen_at.isoformat() if d.last_seen_at else None,
    }


def _grant_dict(g: DeviceGrant) -> dict:
    return {
        "id": g.id, "device_id": g.device_id, "capability": g.capability,
        "scope": json.loads(g.scope_json or "{}"), "status": g.status,
        "granted_at": g.granted_at.isoformat() if g.granted_at else None,
        "revoked_at": g.revoked_at.isoformat() if g.revoked_at else None,
    }