"""AI决策建议 — 一键应用到KPI/预算/行动方案 (路线图R1 2026-08-30)

北极星④决策闭环：AI建议 → 点击应用 → 写库变更 → OperationLog留痕 → 前端可查已应用/未应用。
应用动作复用现有 kpis/budget/action_plans 数据模型，不新建业务接口。
"""
from fastapi import APIRouter, Depends, HTTPException, Query, Request
from sqlalchemy.orm import Session
from sqlalchemy import func
from typing import Optional
from datetime import datetime

from app.database import get_db
from app.deps import get_entity_id, resolve_entity_for_request
from app.auth_middleware import require_auth, require_role
from app.models import AISuggestion, KPIDefinition, KPIValue, OperationLog, BudgetPlan, ActionPlan

router = APIRouter(prefix="/api/cma/ai/suggestions", tags=["AI建议"],
    dependencies=[Depends(require_role("ceo", "finance", "business", "it"))],
)


def _sug_dict(s: AISuggestion) -> dict:
    return {
        "id": s.id,
        "entity_id": s.entity_id,
        "user_id": s.user_id,
        "source": s.source,
        "suggestion_type": s.suggestion_type,
        "target_type": s.target_type,
        "target_id": s.target_id,
        "title": s.title,
        "content": s.content,
        "suggestion_data": s.suggestion_data or {},
        "status": s.status,
        "applied_by": s.applied_by,
        "applied_at": s.applied_at.isoformat() if s.applied_at else None,
        "apply_detail": s.apply_detail or [],
        "created_at": s.created_at.isoformat() if s.created_at else None,
    }


@router.post("")
def create_suggestion(
    request: Request,
    data: dict,
    db: Session = Depends(get_db),
    current_user=Depends(require_auth),
):
    """创建AI建议（前端AI分析/手动保存建议）"""
    suggestion_type = data.get("suggestion_type") or data.get("type")
    title = (data.get("title") or "").strip()
    if not suggestion_type:
        raise HTTPException(400, "缺少 suggestion_type (kpi_target/budget_adjust/action_plan)")
    if not title:
        raise HTTPException(400, "缺少 title")

    entity_id = resolve_entity_for_request(request, data.get("entity_id") or 1)

    sug = AISuggestion(
        entity_id=entity_id,
        user_id=getattr(current_user, "id", None),
        source=data.get("source", "manual"),
        suggestion_type=suggestion_type,
        target_type=data.get("target_type", "kpi"),
        target_id=data.get("target_id"),
        title=title,
        content=data.get("content"),
        suggestion_data=data.get("suggestion_data") or {},
        status="unapplied",
    )
    db.add(sug)
    db.commit()
    db.refresh(sug)
    return {"success": True, "message": "建议已保存", "data": _sug_dict(sug)}


@router.get("")
def list_suggestions(
    status: Optional[str] = Query(None, description="unapplied/applied/dismissed"),
    suggestion_type: Optional[str] = Query(None),
    entity_id: int = Depends(get_entity_id),
    db: Session = Depends(get_db),
):
    """建议列表（前端建议中心/详情页查看已应用/未应用状态）"""
    query = db.query(AISuggestion).filter(AISuggestion.entity_id == entity_id)
    if status:
        query = query.filter(AISuggestion.status == status)
    if suggestion_type:
        query = query.filter(AISuggestion.suggestion_type == suggestion_type)
    items = query.order_by(AISuggestion.created_at.desc()).limit(200).all()
    return {"data": [_sug_dict(s) for s in items], "total": len(items)}


@router.get("/{suggestion_id}")
def get_suggestion(suggestion_id: int, db: Session = Depends(get_db)):
    """建议详情"""
    s = db.query(AISuggestion).filter(AISuggestion.id == suggestion_id).first()
    if not s:
        raise HTTPException(404, "建议不存在")
    return {"data": _sug_dict(s)}


def _apply_kpi_target(db: Session, sug: AISuggestion, params: dict, current_user) -> dict:
    """改KPI目标"""
    target_value = params.get("target_value")
    if target_value is None:
        raise HTTPException(400, "应用kpi_target需要 target_value")
    kpi_id = params.get("kpi_id") or sug.target_id
    if not kpi_id:
        raise HTTPException(400, "缺少 kpi_id")
    kpi = db.query(KPIDefinition).filter(KPIDefinition.id == kpi_id).first()
    if not kpi:
        raise HTTPException(404, f"KPI {kpi_id} 不存在")
    before = kpi.target_value
    kpi.target_value = float(target_value)
    db.flush()
    detail_item = {
        "target_type": "kpi",
        "target_id": kpi.id,
        "target_name": kpi.kpi_name,
        "action": "update_target_value",
        "before": before,
        "after": float(target_value),
    }
    db.add(OperationLog(
        user_id=getattr(current_user, "id", None),
        action="ai_suggestion_apply",
        target_type="kpi",
        target_id=kpi.id,
        detail={
            "suggestion_id": sug.id,
            "suggestion_title": sug.title,
            "apply_action": "kpi_target",
            "before": before,
            "after": float(target_value),
        },
    ))
    return detail_item


def _apply_budget_adjust(db: Session, sug: AISuggestion, params: dict, current_user) -> dict:
    """调预算（BudgetPlan upsert，按 kpi_id+period）"""
    period = params.get("period")
    budget_value = params.get("budget_value")
    if not period or budget_value is None:
        raise HTTPException(400, "应用budget_adjust需要 period + budget_value")
    kpi_id = params.get("kpi_id") or sug.target_id
    if not kpi_id:
        raise HTTPException(400, "缺少 kpi_id")
    kpi = db.query(KPIDefinition).filter(KPIDefinition.id == kpi_id).first()
    if not kpi:
        raise HTTPException(404, f"KPI {kpi_id} 不存在")

    # 解析期间 2026-09 → year=2026 month=9
    try:
        parts = period.split("-")
        year = int(parts[0])
        month = int(parts[1])
    except Exception:
        raise HTTPException(400, f"period格式错误: {period} (需要 YYYY-MM)")

    plan = db.query(BudgetPlan).filter(
        BudgetPlan.entity_id == sug.entity_id,
        BudgetPlan.kpi_id == kpi_id,
        BudgetPlan.period == period,
        BudgetPlan.budget_year == year,
        BudgetPlan.budget_month == month,
        BudgetPlan.status == "active",
    ).first()

    before = None
    if plan:
        before = plan.budget_value
        plan.budget_value = float(budget_value)
    else:
        plan = BudgetPlan(
            entity_id=sug.entity_id,
            kpi_id=kpi_id,
            period=period,
            budget_value=float(budget_value),
            budget_year=year,
            budget_month=month,
            version="v1.0",
            status="active",
            source_type="ai_suggestion",
            calc_logic=f"AI建议应用 #{sug.id}: {sug.title}",
            created_by=getattr(current_user, "name", "") or "",
        )
        db.add(plan)
    db.flush()
    detail_item = {
        "target_type": "budget",
        "target_id": plan.id,
        "target_name": f"{kpi.kpi_name}[{period}]",
        "action": "update_budget" if before is not None else "create_budget",
        "before": before,
        "after": float(budget_value),
    }
    db.add(OperationLog(
        user_id=getattr(current_user, "id", None),
        action="ai_suggestion_apply",
        target_type="budget",
        target_id=plan.id,
        detail={
            "suggestion_id": sug.id,
            "suggestion_title": sug.title,
            "apply_action": "budget_adjust",
            "kpi_id": kpi_id,
            "period": period,
            "before": before,
            "after": float(budget_value),
        },
    ))
    return detail_item


def _apply_action_plan(db: Session, sug: AISuggestion, params: dict, current_user) -> dict:
    """建行动方案"""
    title = (params.get("title") or "").strip() or sug.title
    kpi_id = params.get("kpi_id") or sug.target_id
    if not kpi_id:
        raise HTTPException(400, "缺少 kpi_id")
    kpi = db.query(KPIDefinition).filter(KPIDefinition.id == kpi_id).first()
    if not kpi:
        raise HTTPException(404, f"KPI {kpi_id} 不存在")

    due_date = None
    if params.get("due_date"):
        try:
            due_date = datetime.strptime(str(params["due_date"])[:10], "%Y-%m-%d")
        except Exception:
            due_date = None

    plan = ActionPlan(
        kpi_id=kpi_id,
        title=title,
        description=params.get("description") or sug.content or f"由AI建议 #{sug.id} 生成: {sug.title}",
        assignee=params.get("assignee") or "",
        priority=params.get("priority") or "medium",
        due_date=due_date,
        status="pending",
        progress=0,
        created_by=getattr(current_user, "name", "") or "ai_suggestion",
    )
    db.add(plan)
    db.flush()
    detail_item = {
        "target_type": "action_plan",
        "target_id": plan.id,
        "target_name": title,
        "action": "create_action_plan",
        "before": None,
        "after": plan.id,
    }
    db.add(OperationLog(
        user_id=getattr(current_user, "id", None),
        action="ai_suggestion_apply",
        target_type="action_plan",
        target_id=plan.id,
        detail={
            "suggestion_id": sug.id,
            "suggestion_title": sug.title,
            "apply_action": "action_plan",
            "kpi_id": kpi_id,
            "plan_title": title,
        },
    ))
    return detail_item


_APPLYERS = {
    "kpi_target": _apply_kpi_target,
    "budget_adjust": _apply_budget_adjust,
    "action_plan": _apply_action_plan,
}


@router.post("/{suggestion_id}/apply")
def apply_suggestion(
    suggestion_id: int,
    data: dict,
    db: Session = Depends(get_db),
    current_user=Depends(require_auth),
):
    """应用建议：改KPI目标 / 调预算 / 建行动方案（写库+操作日志留痕）

    Body 示例:
      {"action": "kpi_target", "target_value": 2000000}
      {"action": "budget_adjust", "period": "2026-09", "budget_value": 100000}
      {"action": "action_plan", "title": "...", "assignee": "...", "priority": "high", "due_date": "2026-09-30"}
    """
    sug = db.query(AISuggestion).filter(AISuggestion.id == suggestion_id).first()
    if not sug:
        raise HTTPException(404, "建议不存在")
    if sug.status == "applied":
        raise HTTPException(400, "该建议已应用，不能重复应用")
    if sug.status == "dismissed":
        raise HTTPException(400, "该建议已忽略，如需应用请重新创建")

    action = data.get("action") or sug.suggestion_type
    applier = _APPLYERS.get(action)
    if not applier:
        raise HTTPException(400, f"不支持的应用动作: {action} (支持 kpi_target/budget_adjust/action_plan)")

    # 应用参数 = 请求体参数 覆盖 建议默认参数
    params = dict(sug.suggestion_data or {})
    params.update({k: v for k, v in data.items() if k != "action" and v is not None})

    detail_item = applier(db, sug, params, current_user)
    sug.status = "applied"
    sug.applied_by = getattr(current_user, "name", "") or ""
    sug.applied_user_id = getattr(current_user, "id", None)
    sug.applied_at = datetime.now()
    sug.apply_detail = [detail_item]
    db.commit()
    db.refresh(sug)
    return {
        "success": True,
        "message": "建议已应用并留痕",
        "data": _sug_dict(sug),
    }


@router.post("/{suggestion_id}/dismiss")
def dismiss_suggestion(
    suggestion_id: int,
    db: Session = Depends(get_db),
    current_user=Depends(require_auth),
):
    """忽略建议"""
    sug = db.query(AISuggestion).filter(AISuggestion.id == suggestion_id).first()
    if not sug:
        raise HTTPException(404, "建议不存在")
    sug.status = "dismissed"
    db.commit()
    return {"success": True, "message": "建议已忽略"}