package com.goldenchart.service;

import com.goldenchart.entity.GcFcmToken;
import com.goldenchart.repository.GcFcmTokenRepository;
import com.google.firebase.FirebaseApp;
import com.google.firebase.messaging.AndroidConfig;
import com.google.firebase.messaging.AndroidNotification;
import com.google.firebase.messaging.FirebaseMessaging;
import com.google.firebase.messaging.FirebaseMessagingException;
import com.google.firebase.messaging.Message;
import com.google.firebase.messaging.MessagingErrorCode;
import com.google.firebase.messaging.Notification;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;
import java.util.List;
import java.util.Optional;

@Service
@RequiredArgsConstructor
@Slf4j
public class FcmPushService {

    /** Capacitor Android 앱 알림 채널 (app/android strings.xml 과 동일) */
    private static final String ANDROID_CHANNEL_ID = "goldenchart_trade_signals";

    private final GcFcmTokenRepository tokenRepo;
    private final AppSettingsService appSettingsService;

    @Value("${firebase.enabled:false}")
    private boolean firebaseEnabled;

    @Transactional
    public void registerToken(Long userId, String deviceId, String token) {
        if (token == null || token.isBlank()) return;
        String dev = deviceId != null ? deviceId : "anonymous";
        Optional<GcFcmToken> existing = tokenRepo.findByToken(token);
        if (existing.isPresent()) {
            GcFcmToken t = existing.get();
            t.setUserId(userId);
            t.setDeviceId(dev);
            t.setActive(true);
            t.setLastUsedAt(LocalDateTime.now());
            tokenRepo.save(t);
        } else {
            tokenRepo.save(GcFcmToken.builder()
                    .token(token)
                    .userId(userId)
                    .deviceId(dev)
                    .active(true)
                    .lastUsedAt(LocalDateTime.now())
                    .build());
        }
        log.info("[FCM] token registered device={}", dev);
    }

    @Transactional
    public void deleteByDevice(String deviceId) {
        if (deviceId != null) tokenRepo.deleteByDeviceId(deviceId);
    }

    public boolean isAvailable() {
        return firebaseEnabled && !FirebaseApp.getApps().isEmpty();
    }

    /**
     * 전략 조건 일치(매매 시그널) 시 FCM 푸시 — fcm_push_enabled + 등록된 토큰 대상.
     */
    public void sendTradeSignalIfEnabled(String deviceId, Long userId, String market,
                                         String signalType, double price,
                                         String strategyName, Long signalId) {
        if (!isAvailable()) {
            log.debug("[FCM] skip trade_signal {} {} — Firebase unavailable", market, signalType);
            return;
        }

        var app = appSettingsService.getEntity(userId, deviceId);
        if (!Boolean.TRUE.equals(app.getFcmPushEnabled())) {
            log.debug("[FCM] skip trade_signal {} — fcm_push_enabled=false userId={} deviceId={}",
                    market, userId, deviceId);
            return;
        }

        List<GcFcmToken> tokens = resolveTokens(userId, deviceId);
        if (tokens.isEmpty()) {
            log.info("[FCM] no active tokens for trade_signal market={} userId={} deviceId={}",
                    market, userId, deviceId);
            return;
        }

        String title = "BUY".equals(signalType) ? "🟢 매수 시그널" : "🔴 매도 시그널";
        String body = String.format("%s · ₩%,.0f%s",
                market, price,
                strategyName != null && !strategyName.isBlank() ? " · " + strategyName : "");

        int sent = 0;
        for (GcFcmToken t : tokens) {
            if (sendTradeSignalMessage(t, title, body, market, signalType, price, signalId)) {
                sent++;
            }
        }
        log.info("[FCM] trade_signal sent {}/{} tokens market={} {}", sent, tokens.size(), market, signalType);
    }

    private List<GcFcmToken> resolveTokens(Long userId, String deviceId) {
        if (userId != null) {
            List<GcFcmToken> byUser = tokenRepo.findByUserIdAndActiveTrue(userId);
            if (!byUser.isEmpty()) return byUser;
        }
        if (deviceId != null && !deviceId.isBlank()) {
            return tokenRepo.findByDeviceIdAndActiveTrue(deviceId);
        }
        return List.of();
    }

    private boolean sendTradeSignalMessage(GcFcmToken t, String title, String body,
                                            String market, String signalType,
                                            double price, Long signalId) {
        try {
            Message msg = Message.builder()
                    .setToken(t.getToken())
                    .setNotification(Notification.builder().setTitle(title).setBody(body).build())
                    .setAndroidConfig(AndroidConfig.builder()
                            .setPriority(AndroidConfig.Priority.HIGH)
                            .setNotification(AndroidNotification.builder()
                                    .setChannelId(ANDROID_CHANNEL_ID)
                                    .build())
                            .build())
                    .putData("type", "trade_signal")
                    .putData("signalId", signalId != null ? String.valueOf(signalId) : "")
                    .putData("market", market != null ? market : "")
                    .putData("signalType", signalType != null ? signalType : "")
                    .putData("price", String.valueOf(price))
                    .build();
            FirebaseMessaging.getInstance().send(msg);
            t.setLastUsedAt(LocalDateTime.now());
            tokenRepo.save(t);
            return true;
        } catch (FirebaseMessagingException e) {
            log.warn("[FCM] send failed tokenId={} code={}", t.getId(), e.getMessagingErrorCode());
            if (e.getMessagingErrorCode() == MessagingErrorCode.UNREGISTERED
                    || e.getMessagingErrorCode() == MessagingErrorCode.INVALID_ARGUMENT) {
                t.setActive(false);
                tokenRepo.save(t);
            }
            return false;
        } catch (Exception e) {
            log.warn("[FCM] send error: {}", e.getMessage());
            return false;
        }
    }

    public void sendTest(Long userId, String deviceId) {
        if (!isAvailable()) {
            log.warn("[FCM] test skipped — Firebase not initialized");
            return;
        }
        List<GcFcmToken> tokens = resolveTokens(userId, deviceId);
        if (tokens.isEmpty()) {
            log.warn("[FCM] test skipped — no tokens userId={} deviceId={}", userId, deviceId);
            return;
        }
        for (GcFcmToken t : tokens) {
            try {
                Message msg = Message.builder()
                        .setToken(t.getToken())
                        .setNotification(Notification.builder()
                                .setTitle("GoldenChart 테스트")
                                .setBody("FCM 푸시가 정상 동작합니다.")
                                .build())
                        .putData("type", "test")
                        .build();
                FirebaseMessaging.getInstance().send(msg);
            } catch (Exception e) {
                log.warn("[FCM] test send failed: {}", e.getMessage());
            }
        }
    }
}