from __future__ import annotations

from datetime import datetime
from uuid import uuid4
from zoneinfo import ZoneInfo

from app.repositories.monitoring_repository import MonitoringRepository
from app.services.email_notification_service import email_notification_service


class AlertService:
    def __init__(self) -> None:
        self.repository = MonitoringRepository()
        self.tz = ZoneInfo("Asia/Shanghai")

    @staticmethod
    def _format_amount(value: float | None) -> str:
        if value is None:
            return "-"
        return f"{value:.4f}"

    @staticmethod
    def _format_signed_amount(value: float | None) -> str:
        if value is None:
            return "-"
        return f"{value:+.4f}"

    @staticmethod
    def _format_points(value: float | None) -> str:
        if value is None:
            return "-"
        return f"{value:.2f}"

    @staticmethod
    def _build_benchmark_lookup(snapshot: dict) -> dict[str, float | None]:
        lookup: dict[str, float | None] = {}
        for item in snapshot.get("benchmark_series", []) or []:
            points = item.get("points", []) or []
            lookup[item.get("label", "")] = points[-1].get("value") if points else None
        return lookup

    def _build_enhanced_body(
        self,
        *,
        snapshot: dict,
        title: str,
        summary: str,
        note: str | None = None,
        operation_advice: str | None = None,
        market_context: list[str] | None = None,
    ) -> str:
        benchmarks = self._build_benchmark_lookup(snapshot)
        lines = [
            title,
            "",
            f"交易日期: {snapshot.get('trade_date')}",
            f"快照时间: {snapshot.get('snapshot_time') or snapshot.get('updated_at') or '-'}",
            f"南向总净流入: {self._format_signed_amount(snapshot.get('total_net_inflow'))} 亿港元",
            f"1分钟净变化: {self._format_signed_amount(snapshot.get('one_min_change'))} 亿港元",
            f"5分钟净变化: {self._format_signed_amount(snapshot.get('five_min_change'))} 亿港元",
            f"恒生指数: {self._format_points(benchmarks.get('恒生指数'))}",
            f"恒生科技指数: {self._format_points(benchmarks.get('恒生科技指数'))}",
            "",
            "摘要",
            summary,
        ]

        if market_context:
            lines.extend(["", "市场要点"])
            lines.extend([f"{index}. {item}" for index, item in enumerate(market_context, start=1)])

        if operation_advice:
            lines.extend(["", "操作建议", operation_advice])

        if note:
            lines.extend(["", "备注", note])

        return "\n".join(lines)

    def _send_email(self, subject: str, body: str) -> None:
        config = self.repository.get_system_config()
        email_notification_service.send(
            smtp_host=config.get("smtp_host", ""),
            smtp_port=int(config.get("smtp_port", 465)),
            smtp_username=config.get("smtp_username", ""),
            smtp_password=config.get("smtp_password", ""),
            sender_email=config.get("sender_email", ""),
            recipients=config.get("recipients", []),
            subject=subject,
            text_body=body,
        )

    def _build_record(
        self,
        *,
        snapshot: dict,
        rule_code: str,
        subject: str,
        summary: str,
        description: str,
        trigger_value: float | None,
    ) -> dict:
        return {
            "id": f"push-{uuid4().hex[:12]}",
            "triggered_at": datetime.now(self.tz).isoformat(timespec="seconds"),
            "push_type": "email",
            "rule_code": rule_code,
            "trigger_value_hkd_billion": trigger_value,
            "description": description,
            "email_subject": subject,
            "email_summary": summary,
            "status": "pending",
            "error_message": None,
        }

    def send_snapshot_alert(
        self,
        *,
        snapshot: dict,
        rule_code: str,
        subject: str,
        summary: str,
        description: str,
        trigger_value: float | None,
        body_note: str | None = None,
        body_text: str | None = None,
        operation_advice: str | None = None,
        market_context: list[str] | None = None,
    ) -> dict:
        body = (
            body_text
            if body_text is not None
            else self._build_enhanced_body(
                snapshot=snapshot,
                title="南向资金监控自动告警",
                summary=summary,
                note=body_note,
                operation_advice=operation_advice,
                market_context=market_context,
            )
        )
        record = self._build_record(
            snapshot=snapshot,
            rule_code=rule_code,
            subject=subject,
            summary=summary,
            description=description,
            trigger_value=trigger_value,
        )
        try:
            self._send_email(subject=subject, body=body)
            record["status"] = "sent"
        except Exception as exc:
            record["status"] = "failed"
            record["error_message"] = str(exc)
        self.repository.append_push_record(record)
        return record

    def send_test_alert(self) -> dict:
        snapshot = self.repository.get_latest_snapshot()
        history = self.repository.get_history()
        if not snapshot:
            raise ValueError("未找到可用于测试的快照数据")
        if snapshot.get("total_net_inflow") is None:
            raise ValueError("快照缺少 total_net_inflow，无法发送测试告警")
        total_net_inflow = snapshot.get("total_net_inflow")
        five_min_change = snapshot.get("five_min_change")
        cumulative = history.get("summary", {}).get("cumulative_net_inflow_hkd_billion")
        summary = (
            f"{snapshot.get('trade_date')} 南向资金当前净流入 {self._format_signed_amount(total_net_inflow)} 亿港元，"
            f"5分钟净变化 {self._format_signed_amount(five_min_change)} 亿港元，"
            f"统计区间累计 {self._format_amount(cumulative)} 亿港元。"
        )
        body = self._build_enhanced_body(
            snapshot=snapshot,
            title="南向资金监控提醒",
            summary=summary,
            market_context=[
                "南向资金尾盘仍以净流出为主。",
                "恒生科技指数仍处在弱修复阶段。",
            ],
            operation_advice="南向资金仍偏弱，短线先控制仓位，等待南向重新转正后再考虑分批回补恒生科技方向。",
        )
        return self.send_snapshot_alert(
            snapshot=snapshot,
            rule_code="manual_test_alert",
            subject=f"[南向资金监控] {snapshot.get('trade_date')} 港股操作建议",
            summary=summary,
            description="用于发送简版正式样式邮件。",
            trigger_value=total_net_inflow,
            body_text=body,
        )


alert_service = AlertService()