from __future__ import annotations

from datetime import UTC, datetime, timedelta
from typing import Any

from sqlalchemy import or_, select

from app.models.financial_record import ExpenseClaim
from app.services.expense_claim_constants import (
    AI_REVIEW_LOOKBACK_DAYS,
    AI_REVIEW_REPEAT_RISK_BLOCK_COUNT,
    AI_REVIEW_REPEAT_RISK_WARNING_COUNT,
)
from app.services.expense_claim_item_sync import ExpenseClaimItemSyncMixin
from app.services.expense_claim_platform_risk import ExpenseClaimPlatformRiskMixin
from app.services.expense_claim_policy_review import ExpenseClaimPolicyReviewMixin


class ExpenseClaimRiskReviewMixin(
    ExpenseClaimPlatformRiskMixin,
    ExpenseClaimPolicyReviewMixin,
    ExpenseClaimItemSyncMixin,
):
    def _run_ai_submission_review(self, claim: ExpenseClaim) -> dict[str, Any]:
        base_flags = list(claim.risk_flags_json or [])
        attachment_flags = [
            flag
            for flag in base_flags
            if isinstance(flag, dict) and str(flag.get("source") or "").strip() == "attachment_analysis"
        ]
        preserved_flags = [
            flag
            for flag in base_flags
            if not (isinstance(flag, dict) and str(flag.get("source") or "").strip() == "submission_review")
        ]

        review_flags: list[dict[str, Any]] = []
        attention_reasons: list[str] = []

        high_attachment_flags = [
            flag
            for flag in attachment_flags
            if str(flag.get("severity") or "").strip().lower() == "high"
        ]
        medium_attachment_flags = [
            flag
            for flag in attachment_flags
            if str(flag.get("severity") or "").strip().lower() == "medium"
        ]
        if high_attachment_flags:
            attention_reasons.append("存在高风险票据，需审批人重点复核。")
            review_flags.append(
                {
                    "source": "submission_review",
                    "severity": "high",
                    "label": "AI预审重点复核",
                    "message": (
                        f"AI预审发现 {len(high_attachment_flags)} 条高风险附件，"
                        "已随单流转给审批人重点复核。"
                    ),
                }
            )
        elif medium_attachment_flags:
            review_flags.append(
                {
                    "source": "submission_review",
                    "severity": "medium",
                    "label": "AI预审提醒",
                    "message": f"AI预审发现 {len(medium_attachment_flags)} 条中风险附件，已随单流转给审批人复核。",
                }
            )

        manager_name = self._resolve_claim_manager_name(claim)
        if not manager_name:
            attention_reasons.append("未识别到该员工的直属领导，需审批环节补充分配。")
            review_flags.append(
                {
                    "source": "submission_review",
                    "severity": "medium",
                    "label": "审批链待分配",
                    "message": "AI预审发现直属领导缺失，已提交到审批环节等待分配或复核。",
                }
            )

        historical_risk_count = self._count_recent_risky_claims(claim)
        if historical_risk_count >= AI_REVIEW_REPEAT_RISK_BLOCK_COUNT:
            review_flags.append(
                {
                    "source": "submission_review",
                    "severity": "medium",
                    "label": "历史风险偏高",
                    "message": (
                        f"近 {AI_REVIEW_LOOKBACK_DAYS} 天内该员工已有 {historical_risk_count} 笔带风险标记的报销，"
                        "本次已追加到审批链重点关注。"
                    ),
                }
            )
        elif historical_risk_count >= AI_REVIEW_REPEAT_RISK_WARNING_COUNT:
            review_flags.append(
                {
                    "source": "submission_review",
                    "severity": "low",
                    "label": "历史风险提醒",
                    "message": (
                        f"近 {AI_REVIEW_LOOKBACK_DAYS} 天内该员工已有 {historical_risk_count} 笔带风险标记的报销，"
                        "建议直属领导重点复核。"
                    ),
                }
            )

        travel_review = self._run_travel_policy_review(claim)
        attention_reasons.extend(travel_review["blocking_reasons"])
        review_flags.extend(travel_review["flags"])

        scene_policy_review = self._run_scene_policy_review(claim)
        attention_reasons.extend(scene_policy_review["blocking_reasons"])
        review_flags.extend(scene_policy_review["flags"])

        platform_risk_review = self.evaluate_platform_risk_rules(claim)
        attention_reasons.extend(platform_risk_review["blocking_reasons"])
        review_flags.extend(platform_risk_review["flags"])

        if attention_reasons:
            summary_message = "AI预审发现需审批重点关注事项：" + "；".join(
                dict.fromkeys(attention_reasons)
            )
            review_flags.insert(
                0,
                {
                    "source": "submission_review",
                    "severity": "medium",
                    "label": "AI预审重点复核",
                    "message": summary_message,
                },
            )

        return {
            "status": "submitted",
            "approval_stage": "直属领导审批",
            "risk_flags": preserved_flags + review_flags,
            "message": (
                f"报销单 {claim.claim_no} 已完成 AI预审，"
                f"现已提交给直属领导 {manager_name or '审批人'} 审批。"
            ),
            "passed": True,
        }

    @staticmethod
    def _resolve_claim_manager_name(claim: ExpenseClaim) -> str:
        if claim.employee is not None:
            if claim.employee.manager is not None and claim.employee.manager.name:
                return str(claim.employee.manager.name).strip()
            if claim.employee.organization_unit is not None and claim.employee.organization_unit.manager_name:
                return str(claim.employee.organization_unit.manager_name).strip()
        return ""

    def _count_recent_risky_claims(self, claim: ExpenseClaim) -> int:
        filters = []
        if claim.employee_id:
            filters.append(ExpenseClaim.employee_id == claim.employee_id)
        elif claim.employee_name:
            filters.append(ExpenseClaim.employee_name == claim.employee_name)
        if not filters:
            return 0

        since = datetime.now(UTC) - timedelta(days=AI_REVIEW_LOOKBACK_DAYS)
        stmt = (
            select(ExpenseClaim)
            .where(or_(*filters))
            .where(ExpenseClaim.id != claim.id)
            .where(ExpenseClaim.occurred_at >= since)
        )
        recent_claims = list(self.db.scalars(stmt).all())
        return sum(1 for item in recent_claims if list(item.risk_flags_json or []))