"""工作台服务（M4 ⑧）：区块实时聚合编排 + 最近动态分页。

设计决策（2026-10-19）：
- **只读**：不落库、不写审计（读操作不入操作日志）；总览只做 SQL 聚合，
  不复用报表的部门汇总（后者会加载整月台账，过重）
- **待办与预警实时派生**：不建待办/预警表、不引调度器；处置动作本身
  已有操作日志可追溯。与 FR-035「预警产生/消除留痕」的差距记录在
  计划开放项，待业务确认是否物化
- 同步记录与采集开关分别展示；读取关闭不抹掉已完成的采集记录
- 预警阈值走参数体系（``warning.*``），一次请求只解析一次快照
- **最近动态独立分页**（2026-10-23）：操作日志可能很长，聚合响应里
  只能塞前 20 条；拆成独立端点后翻页只重取这张列表
"""

from datetime import date, datetime, timedelta
from decimal import Decimal

from sqlalchemy import func, inspect, select
from sqlalchemy.orm import Session

from app.core.config import get_settings
from app.core.exceptions import BadRequestError
from app.core.month import validate_month
from app.models import TPlusSyncBatch
from app.repositories import dashboard_repository, operation_log_repository
from app.repositories.query_utils import LogFilters
from app.schemas.dashboard import ActivityItem, ActivityPageOut, ActivityQuery
from app.services import approval_service

# 工作台只展示摘要，完整列表跳转对应管理页
_TODO_LIMIT = 5
_WARNING_LIMIT = 20
_TREND_MONTHS = 6

_ORDER_TYPE_LABELS = {1: "二次分配方案", 2: "月度结算", 3: "调整单"}


def get_dashboard(session: Session, month: str | None = None, *, current_user) -> dict:
    """三区块一次性出数（前端一次请求渲染整页）。

    待办按当前用户角色只展示其可操作节点（admin 可查看全部在途单）；
    风险预警仍是全局经营视角，不按人裁剪。
    最近动态不在此返回 —— 它是分页列表，走 ``list_activities``。
    """
    resolved = _normalize_month(month)
    warning_params = _warning_params(session)
    from app.services.authorization_service import calculate

    permissions = calculate(session, current_user)["permissions"]
    pending_statuses = approval_service.pending_statuses_for_roles([
        role for role in ("finance", "leader") if "approvals:" + role in permissions
    ])
    sync = _sync_status(session)
    return {
        "month": resolved,
        "overview": _overview(session, resolved),
        "todos": _todos(session, pending_statuses, sync),
        "warnings": _warnings(session, warning_params, sync),
        "sync": sync,
    }


def _sync_status(session: Session) -> dict:
    """只读本地批次元数据，不连接源库，兼容尚未应用自动化迁移的开发库。"""
    settings = get_settings()
    result = {
        "available": False,
        "enabled": settings.t_plus_enabled,
        "automation_enabled": settings.t_plus_automation_enabled,
        "latest_status": None,
        "last_success_at": None,
        "historical_failure_total": 0,
    }
    if not inspect(session.connection()).has_table(TPlusSyncBatch.__tablename__):
        return result
    # 关联检查成功不能替代数据采集成功；仅查询原有列，避免加载 V20 新字段。
    reads = TPlusSyncBatch.sync_mode.in_(("FULL", "INCREMENTAL"))
    result["available"] = True
    result["latest_status"] = session.scalar(
        select(TPlusSyncBatch.status).where(reads).order_by(TPlusSyncBatch.id.desc()).limit(1)
    )
    result["last_success_at"] = session.scalar(
        select(func.max(TPlusSyncBatch.finished_at)).where(
            reads, TPlusSyncBatch.status == "SUCCEEDED"
        )
    )
    result["historical_failure_total"] = session.scalar(
        select(func.count()).select_from(TPlusSyncBatch).where(
            reads, TPlusSyncBatch.status.in_(("FAILED", "PARTIAL"))
        )
    ) or 0
    return result


def _normalize_month(month: str | None) -> str:
    """未传月份按当月；非法月份在入口拦成 400（避免 500）。"""
    if not month:
        today = date.today()
        return f"{today.year:04d}-{today.month:02d}"
    try:
        return validate_month(month)
    except ValueError as exc:
        raise BadRequestError(str(exc)) from exc


def _shift_month(month: str, delta: int) -> str:
    """YYYY-MM 平移 delta 个月（用于近 N 个月窗口）。"""
    year, mon = int(month[:4]), int(month[5:7])
    index = year * 12 + (mon - 1) + delta
    return f"{index // 12:04d}-{index % 12 + 1:02d}"


def _month_start(month: str) -> date:
    """YYYY-MM → 该月首日（范围查询边界，避免函数列过滤）。"""
    return date(int(month[:4]), int(month[5:7]), 1)


def _trend_months(month: str) -> list[str]:
    """窗口为「当月及之前共 6 个月」，升序返回便于前端画图。"""
    return [_shift_month(month, offset) for offset in range(-(_TREND_MONTHS - 1), 1)]


def _overview(session: Session, month: str) -> dict:
    """经营绩效总览（FR-033）：口径与台账/月结一致。"""
    sums = dashboard_repository.sum_month_performance(session, month)
    settlement = dashboard_repository.get_month_settlement(session, month)
    months = _trend_months(month)
    performance = dashboard_repository.performance_trend(session, months)
    receipts = dashboard_repository.receipt_trend(
        session,
        start_date=_month_start(months[0]),
        end_date=_month_start(_shift_month(months[-1], 1)),
    )
    return {
        "month": month,
        "performance_total": _dec(sums["performance_total"]),
        "payable_total": _dec(sums["payable_total"]),
        "person_count": int(sums["person_count"]),
        "team_count": dashboard_repository.count_active_managers(session),
        "settlement": {
            "exists": settlement is not None,
            "status": settlement.status if settlement else None,
            "total_performance": settlement.total_performance if settlement else None,
            "total_payable": settlement.total_payable if settlement else None,
            "locked_at": settlement.locked_at if settlement else None,
        },
        "trend": [
            {
                "month": item,
                "performance_total": _dec(performance.get(item)),
                "receipt_total": _dec(receipts.get(item)),
            }
            for item in months
        ],
        "note": (
            "绩效按台账归属月统计（二次分配按参与人拆分后求和，不重复不计漏）；"
            "回款按到账月统计（含尚未核算的回款）；不含经理团队分成与调整单"
        ),
    }


def _todos(session: Session, pending_statuses: tuple[int, ...], sync: dict) -> dict:
    """待办事项（FR-034，澄清 #11 起步范围）。

    ``pending_statuses`` 已按当前用户角色解析：财务只看待财务复核、
    领导只看待领导审核；admin 查看全部在途单。
    """
    orders = dashboard_repository.list_pending_approvals(
        session, statuses=pending_statuses, limit=_TODO_LIMIT
    )
    receipts = dashboard_repository.list_unassigned_receipts(session, limit=_TODO_LIMIT)
    return {
        "pending_approval_total": dashboard_repository.count_pending_approvals(
            session, statuses=pending_statuses
        ),
        "pending_approvals": [
            {
                "order_id": order.id,
                "order_no": order.order_no,
                "order_type": order.order_type,
                "submitter_name": order.submitter_name,
                "create_time": order.create_time,
            }
            for order in orders
        ],
        "unassigned_receipt_total": dashboard_repository.count_unassigned_receipts(session),
        "unassigned_receipts": [
            {
                "receipt_id": row[0].id,
                "receipt_batch_no": row[0].receipt_batch_no,
                "business_id": row[0].business_id,
                "business_no": row.business_no,
                "amount": row[0].amount,
                "receipt_date": row[0].receipt_date,
            }
            for row in receipts
        ],
        "sync_available": sync["available"],
        "sync_failure_total": sync["historical_failure_total"],
    }


def _warning_params(session: Session) -> dict:
    """预警参数一次解析（阈值参数化，澄清 #10）。"""
    from app.services.param_service import parse_fraction, resolve_snapshot

    snapshot = resolve_snapshot(session, date.today())
    return {
        "enabled": snapshot.get("warning.enabled") == "1",
        "receipt_overdue_days": int(parse_fraction(snapshot.get("warning.receipt.overdue.days"))),
        "approval_timeout_days": int(parse_fraction(snapshot.get("warning.approval.timeout.days"))),
    }


def _warnings(session: Session, params: dict, sync: dict) -> dict:
    """风险预警（FR-035）；采集状态与经营预警开关分别展示。"""
    if not params["enabled"]:
        return {
            "enabled": False,
            "receipt_overdue_days": params["receipt_overdue_days"],
            "approval_timeout_days": params["approval_timeout_days"],
            "items": [],
            "total": 0,
            "receipt_overdue_total": 0,
            "approval_timeout_total": 0,
            "sync_available": sync["available"],
        }

    receipt_cutoff = date.today() - timedelta(days=params["receipt_overdue_days"])
    approval_cutoff = datetime.now() - timedelta(days=params["approval_timeout_days"])
    shipments = dashboard_repository.list_overdue_shipments(
        session, cutoff=receipt_cutoff, limit=_WARNING_LIMIT
    )
    orders = dashboard_repository.list_overdue_approvals(
        session, cutoff=approval_cutoff, limit=_WARNING_LIMIT
    )

    items = [
        {
            "code": "receipt_overdue",
            "level": "danger",
            "object_type": "shipment",
            "object_id": row[0].id,
            "title": f"发货批次 {row[0].shipment_no} 逾期未回款",
            "detail": (
                f"业务 {row.business_no or row[0].business_id} 发货日 {row[0].ship_date}，"
                f"超过 {params['receipt_overdue_days']} 天无回款记录"
            ),
            "suggest": "联系客户催收，或核对回款批次指定关系",
            "link": "/business/shipments",
        }
        for row in shipments
    ]
    items += [
        {
            "code": "approval_timeout",
            "level": "warning",
            "object_type": "approval_order",
            "object_id": order.id,
            "title": f"审批单 {order.order_no} 超时未处理",
            "detail": (
                f"{_ORDER_TYPE_LABELS.get(order.order_type, '审批')}由 "
                f"{order.submitter_name or '—'} 提交于 {order.create_time:%Y-%m-%d %H:%M}，"
                f"已超过 {params['approval_timeout_days']} 天"
            ),
            "suggest": "在审批管理中复核或退回",
            "link": "/system/approvals",
        }
        for order in orders
    ]
    receipt_overdue_total = dashboard_repository.count_overdue_shipments(
        session, cutoff=receipt_cutoff
    )
    approval_timeout_total = dashboard_repository.count_overdue_approvals(
        session, cutoff=approval_cutoff
    )
    return {
        "enabled": True,
        "receipt_overdue_days": params["receipt_overdue_days"],
        "approval_timeout_days": params["approval_timeout_days"],
        "items": items,
        # items 有展示上限（_WARNING_LIMIT），徽标计数必须用全量命中数
        "total": receipt_overdue_total + approval_timeout_total,
        "receipt_overdue_total": receipt_overdue_total,
        "approval_timeout_total": approval_timeout_total,
        "sync_available": sync["available"],
    }


def list_activities(session: Session, query: ActivityQuery) -> ActivityPageOut:
    """最近动态分页（FR-036）：以操作日志为唯一来源（写操作即留痕）。

    模块筛选项与列表同源返回（全量模块名，不随当前页变化），
    前端模块下拉不必另取一次全量。
    """
    repo_query = operation_log_repository.OperationLogListQuery(
        filters=LogFilters(),
        offset=query.offset,
        limit=query.page_size,
        module=query.module,
    )
    logs = operation_log_repository.list_logs(session, repo_query)
    total = operation_log_repository.count_logs(session, repo_query)
    return ActivityPageOut(
        records=[
            ActivityItem(
                id=log.id,
                module=log.module,
                action=log.action,
                summary=log.summary,
                username=log.username,
                success=log.success,
                create_time=log.create_time,
            )
            for log in logs
        ],
        total=total,
        page_num=query.page_num,
        page_size=query.page_size,
        modules=operation_log_repository.distinct_modules(session),
    )


def _dec(value) -> Decimal | None:
    """SQL 聚合结果转 Decimal（SUM 可能返回 int，None 原样返回）。"""
    if value is None:
        return None
    return value if isinstance(value, Decimal) else Decimal(str(value))