package com.xuqm.bugcollect.service;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.xuqm.bugcollect.dto.*;
import com.xuqm.bugcollect.entity.*;
import com.xuqm.bugcollect.repository.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.*;

@Service
public class LogService {

    private static final Logger log = LoggerFactory.getLogger(LogService.class);

    private final LogIssueRepository issueRepository;
    private final LogIssueEventRepository issueEventRepository;
    private final LogIssueUserRepository issueUserRepository;
    private final LogEventRepository eventRepository;
    private final WebhookService webhookService;
    private final ObjectMapper objectMapper;

    public LogService(LogIssueRepository issueRepository,
                      LogIssueEventRepository issueEventRepository,
                      LogIssueUserRepository issueUserRepository,
                      LogEventRepository eventRepository,
                      WebhookService webhookService,
                      ObjectMapper objectMapper) {
        this.issueRepository = issueRepository;
        this.issueEventRepository = issueEventRepository;
        this.issueUserRepository = issueUserRepository;
        this.eventRepository = eventRepository;
        this.webhookService = webhookService;
        this.objectMapper = objectMapper;
    }

    @Transactional
    public void processIssueBatch(IssueBatchRequest request) {
        for (IssueBatchRequest.IssueEventItem item : request.events()) {
            try {
                processSingleIssue(item);
            } catch (Exception e) {
                log.error("Failed to process issue event: fingerprint={}", item.fingerprint(), e);
            }
        }
    }

    private void processSingleIssue(IssueBatchRequest.IssueEventItem item) {
        if (item.eventId() != null && !item.eventId().isBlank()
                && issueEventRepository.existsByAppKeyAndEventId(item.appKey(), item.eventId())) {
            log.debug("Skipping duplicate eventId={} appKey={}", item.eventId(), item.appKey());
            return;
        }

        LocalDateTime now = LocalDateTime.now();
        LocalDateTime eventTime = item.timestamp() > 0
                ? Instant.ofEpochMilli(item.timestamp()).atZone(ZoneOffset.UTC).toLocalDateTime()
                : now;

        String exType  = item.exception() != null ? item.exception().type()       : "";
        String exValue = item.exception() != null ? item.exception().value()      : "";
        String stack   = item.exception() != null ? item.exception().stacktrace() : "";
        String title   = truncate(exType + (!exValue.isEmpty() ? ": " + exValue : ""), 500);
        String userId  = item.user() != null ? item.user().id() : null;

        Optional<LogIssueEntity> existing = issueRepository.findByAppKeyAndFingerprint(item.appKey(), item.fingerprint());

        LogIssueEntity issue;
        boolean isNew = false;
        if (existing.isPresent()) {
            issue = existing.get();
            issue.setLastSeenAt(now);
            issue.setCount(issue.getCount() + 1);
            if (userId != null && !issueUserRepository.existsByIssueIdAndUserId(issue.getId(), userId)) {
                LogIssueUserEntity iu = new LogIssueUserEntity();
                iu.setIssueId(issue.getId());
                iu.setUserId(userId);
                iu.setFirstSeenAt(now);
                issueUserRepository.save(iu);
                issue.setAffectedUsers(issue.getAffectedUsers() + 1);
            }
            if (!"open".equals(issue.getStatus())) issue.setStatus("open");
            issueRepository.save(issue);
        } else {
            issue = new LogIssueEntity();
            issue.setAppKey(item.appKey());
            issue.setFingerprint(item.fingerprint());
            issue.setLevel(item.level());
            issue.setType(item.level()); // backward compat column
            issue.setStatus("open");
            issue.setTitle(title);
            issue.setFirstSeenAt(eventTime);
            issue.setLastSeenAt(now);
            issue.setCount(1);
            issue.setAffectedUsers(userId != null ? 1 : 0);
            issue.setPlatform(item.platform());
            issue.setRelease(item.release());
            issue = issueRepository.save(issue);
            isNew = true;
        }

        LogIssueEventEntity eventEntity = new LogIssueEventEntity();
        eventEntity.setIssueId(issue.getId());
        eventEntity.setEventId(item.eventId());
        eventEntity.setAppKey(item.appKey());
        eventEntity.setLevel(item.level());
        eventEntity.setUserId(userId);
        eventEntity.setExceptionType(exType);
        eventEntity.setExceptionValue(exValue);
        eventEntity.setMessage(exValue);
        eventEntity.setStack(stack);
        eventEntity.setPlatform(item.platform());
        eventEntity.setRelease(item.release());
        eventEntity.setEnvironment(item.environment() != null ? item.environment() : "production");
        eventEntity.setDevice(item.device() != null ? toJson(item.device()) : null);
        eventEntity.setTags(item.tags() != null ? toJson(item.tags()) : null);
        if (item.breadcrumbs() != null && !item.breadcrumbs().isEmpty()) {
            eventEntity.setBreadcrumbs(toJson(item.breadcrumbs()));
        }
        eventEntity.setCreatedAt(eventTime);
        issueEventRepository.save(eventEntity);

        if (isNew) triggerWebhookAsync(issue);
        triggerSymbolicationAsync(issue.getId(), item.appKey(), item.platform(), item.release());
    }

    @Async
    void triggerWebhookAsync(LogIssueEntity issue) {
        try {
            webhookService.checkAndNotify(issue);
        } catch (Exception e) {
            log.error("Webhook trigger failed for issue={}", issue.getId(), e);
        }
    }

    @Async
    void triggerSymbolicationAsync(Long issueId, String appKey, String platform, String release) {
        log.debug("Symbolication triggered issueId={} appKey={} platform={} release={}", issueId, appKey, platform, release);
    }

    @Transactional
    public void processEventBatch(EventBatchRequest request) {
        for (EventBatchRequest.EventItem item : request.events()) {
            try {
                if (item.eventId() != null && !item.eventId().isBlank()
                        && eventRepository.existsByAppKeyAndEventId(item.appKey(), item.eventId())) {
                    continue;
                }
                LogEventEntity entity = new LogEventEntity();
                entity.setEventId(item.eventId());
                entity.setAppKey(item.appKey());
                entity.setName(item.name());
                entity.setUserId(item.user() != null ? item.user().id() : null);
                entity.setProperties(item.properties() != null ? toJson(item.properties()) : null);
                entity.setPlatform(item.platform());
                entity.setRelease(item.release());
                entity.setEnvironment(item.environment() != null ? item.environment() : "production");
                entity.setDevice(item.device() != null ? toJson(item.device()) : null);
                entity.setSdkName(item.sdk() != null ? item.sdk().name() : null);
                entity.setSdkVersion(item.sdk() != null ? item.sdk().version() : null);
                entity.setCreatedAt(
                    item.timestamp() > 0
                        ? Instant.ofEpochMilli(item.timestamp()).atZone(ZoneOffset.UTC).toLocalDateTime()
                        : LocalDateTime.now()
                );
                eventRepository.save(entity);
            } catch (Exception e) {
                log.error("Failed to process event: name={}", item.name(), e);
            }
        }
    }

    @Transactional(readOnly = true)
    public Page<IssueResponse> queryIssues(String appKey, String level, String platform,
                                           String status, String q, String assignee, String environment,
                                           String from, String to, int page, int size) {
        Pageable pageable = PageRequest.of(page, size, Sort.by(Sort.Direction.DESC, "lastSeenAt"));
        Page<LogIssueEntity> result = issueRepository.findByFilters(
                appKey, level, platform, status, q, assignee, environment, parseDate(from), parseDate(to), pageable);
        return result.map(this::toIssueResponse);
    }

    @Transactional(readOnly = true)
    public IssueResponse getIssueDetail(Long id) {
        LogIssueEntity issue = issueRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("Issue not found: " + id));
        Pageable pageable = PageRequest.of(0, 20, Sort.by(Sort.Direction.DESC, "createdAt"));
        List<IssueEventResponse> events = issueEventRepository
                .findByIssueIdOrderByCreatedAtDesc(issue.getId(), pageable)
                .getContent()
                .stream()
                .map(this::toIssueEventResponse)
                .toList();
        return new IssueResponse(
                issue.getId(), issue.getAppKey(), issue.getFingerprint(),
                issue.getLevel(),
                issue.getStatus() != null ? issue.getStatus() : "open",
                issue.getTitle(), issue.getFirstSeenAt(), issue.getLastSeenAt(),
                issue.getCount(), issue.getAffectedUsers(),
                issue.getAssignee(), issue.getPlatform(), issue.getRelease(), events
        );
    }

    @Transactional(readOnly = true)
    public Page<IssueEventResponse> getIssueEvents(Long issueId, String from, String to, int page, int size) {
        if (!issueRepository.existsById(issueId)) {
            throw new IllegalArgumentException("Issue not found: " + issueId);
        }
        Pageable pageable = PageRequest.of(page, size, Sort.by(Sort.Direction.DESC, "createdAt"));
        LocalDateTime fromDate = parseDate(from);
        LocalDateTime toDate   = parseDate(to) != null ? parseDate(to).plusDays(1) : null;
        Page<LogIssueEventEntity> result = (fromDate != null && toDate != null)
                ? issueEventRepository.findByIssueIdAndCreatedAtBetweenOrderByCreatedAtDesc(issueId, fromDate, toDate, pageable)
                : issueEventRepository.findByIssueIdOrderByCreatedAtDesc(issueId, pageable);
        return result.map(this::toIssueEventResponse);
    }

    @Transactional(readOnly = true)
    public IssueTrendResponse getIssueTrend(Long issueId, String from, String to) {
        if (!issueRepository.existsById(issueId)) {
            throw new IllegalArgumentException("Issue not found: " + issueId);
        }
        LocalDate fromDate = from != null ? LocalDate.parse(from) : LocalDate.now().minusDays(13);
        LocalDate toDate   = to   != null ? LocalDate.parse(to)   : LocalDate.now();

        List<Object[]> rows = issueEventRepository.findDailyCountsByIssueId(
                issueId, fromDate.atStartOfDay(), toDate.plusDays(1).atStartOfDay());

        Map<String, long[]> dayMap = new LinkedHashMap<>();
        for (LocalDate c = fromDate; !c.isAfter(toDate); c = c.plusDays(1)) {
            dayMap.put(c.toString(), new long[]{0, 0});
        }
        for (Object[] row : rows) {
            LocalDateTime dt = (LocalDateTime) row[0];
            String day = dt.toLocalDate().toString();
            dayMap.put(day, new long[]{((Number) row[1]).longValue(), ((Number) row[2]).longValue()});
        }
        List<IssueTrendResponse.TrendPoint> points = dayMap.entrySet().stream()
                .map(e -> new IssueTrendResponse.TrendPoint(e.getKey(), e.getValue()[0], e.getValue()[1]))
                .toList();
        return new IssueTrendResponse(issueId, points);
    }

    @Transactional
    public void resolveIssue(Long id) {
        LogIssueEntity issue = issueRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("Issue not found: " + id));
        issue.setStatus("resolved");
        issueRepository.save(issue);
    }

    @Transactional
    public void ignoreIssue(Long id) {
        LogIssueEntity issue = issueRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("Issue not found: " + id));
        issue.setStatus("ignored");
        issueRepository.save(issue);
    }

    @Transactional
    public void assignIssue(Long id, String assignee) {
        issueRepository.updateAssignee(id, assignee);
    }

    @Transactional
    public void bulkUpdateIssues(String appKey, List<Long> ids, String action) {
        String status = switch (action) {
            case "resolve" -> "resolved";
            case "ignore"  -> "ignored";
            case "reopen"  -> "open";
            default -> throw new IllegalArgumentException("Unknown action: " + action);
        };
        issueRepository.bulkUpdateStatus(appKey, ids, status);
    }

    @Transactional(readOnly = true)
    public List<IssueResponse> getFrequencyRankings(String appKey, String from, String to, int limit) {
        return issueRepository.findTopByFrequency(appKey, parseDate(from), parseDate(to), PageRequest.of(0, limit))
                .stream().map(this::toIssueResponse).toList();
    }

    @Transactional(readOnly = true)
    public List<IssueResponse> getRiskRankings(String appKey, String from, String to, int limit) {
        return issueRepository.findTopByRisk(appKey, parseDate(from), parseDate(to), PageRequest.of(0, limit))
                .stream().map(this::toIssueResponse).toList();
    }

    @Transactional(readOnly = true)
    public Page<IssueEventResponse> queryEvents(String appKey, String name, String userId,
                                                String from, String to, int page, int size) {
        LocalDateTime fromDate = parseDate(from);
        LocalDateTime toDate   = parseDate(to) != null ? parseDate(to).plusDays(1) : LocalDateTime.now();
        if (fromDate == null) fromDate = LocalDateTime.now().minusDays(7);
        Pageable pageable = PageRequest.of(page, size, Sort.by(Sort.Direction.DESC, "createdAt"));
        Page<LogEventEntity> result;
        if (name != null && userId != null) {
            result = eventRepository.findByAppKeyAndNameAndUserIdAndCreatedAtBetween(appKey, name, userId, fromDate, toDate, pageable);
        } else if (name != null) {
            result = eventRepository.findByAppKeyAndNameAndCreatedAtBetween(appKey, name, fromDate, toDate, pageable);
        } else {
            result = eventRepository.findByAppKeyAndCreatedAtBetween(appKey, fromDate, toDate, pageable);
        }
        return result.map(e -> new IssueEventResponse(
                e.getId(), null, null, e.getAppKey(), e.getUserId(), e.getSessionId(),
                null, null, e.getName(), null, null, null, e.getProperties(),
                null, e.getPlatform(), e.getRelease(), e.getEnvironment(), null, null, e.getCreatedAt()
        ));
    }

    @Transactional(readOnly = true)
    public FunnelResponse queryFunnel(String appKey, List<String> steps, String from, String to) {
        List<Object[]> rawData = eventRepository.findFunnelData(appKey, steps, parseDate(from), parseDate(to));

        Map<String, Set<String>> sessionsPerStep = new LinkedHashMap<>();
        for (String step : steps) sessionsPerStep.put(step, new HashSet<>());
        for (Object[] row : rawData) {
            String sid  = (String) row[0];
            String name = (String) row[1];
            if (sessionsPerStep.containsKey(name) && sid != null) sessionsPerStep.get(name).add(sid);
        }

        List<Long>   counts = steps.stream().map(s -> (long) sessionsPerStep.get(s).size()).toList();
        long         first  = counts.isEmpty() ? 1 : Math.max(counts.getFirst(), 1);
        List<Double> rates  = counts.stream().map(c -> Math.round((double) c / first * 1000.0) / 10.0).toList();
        return new FunnelResponse(steps, counts, rates);
    }

    @Transactional(readOnly = true)
    public OverviewResponse getOverview(String appKey, String from, String to) {
        LocalDateTime fromDate = parseDate(from);
        LocalDateTime toDate   = parseDate(to);

        long totalIssues    = issueRepository.countByAppKeyAndFirstSeenAtBetween(appKey, fromDate, toDate);
        long openIssues     = issueRepository.countByAppKeyAndStatus(appKey, "open");
        long todayNewIssues = issueRepository.countByAppKeyAndFirstSeenAtAfter(appKey, LocalDate.now().atStartOfDay());

        List<OverviewResponse.DailyCrashRate> trend = new ArrayList<>();
        if (fromDate != null && toDate != null) {
            for (LocalDate c = fromDate.toLocalDate(), end = toDate.toLocalDate(); !c.isAfter(end); c = c.plusDays(1)) {
                long dayCount = issueRepository.countByAppKeyAndFirstSeenAtBetween(
                        appKey, c.atStartOfDay(), c.plusDays(1).atStartOfDay());
                trend.add(new OverviewResponse.DailyCrashRate(c.toString(), dayCount, 0.0));
            }
        }
        return new OverviewResponse(totalIssues, todayNewIssues, openIssues, trend);
    }

    @Transactional
    public void deleteIssueAndEvents(Long issueId) {
        issueEventRepository.deleteByIssueId(issueId);
        issueRepository.deleteById(issueId);
    }

    private IssueResponse toIssueResponse(LogIssueEntity issue) {
        return new IssueResponse(
                issue.getId(), issue.getAppKey(), issue.getFingerprint(),
                issue.getLevel(),
                issue.getStatus() != null ? issue.getStatus() : "open",
                issue.getTitle(), issue.getFirstSeenAt(), issue.getLastSeenAt(),
                issue.getCount(), issue.getAffectedUsers(),
                issue.getAssignee(), issue.getPlatform(), issue.getRelease(), null
        );
    }

    private IssueEventResponse toIssueEventResponse(LogIssueEventEntity e) {
        IssueEventResponse.ExceptionInfo exception = new IssueEventResponse.ExceptionInfo(
                e.getExceptionType(),
                e.getExceptionValue() != null ? e.getExceptionValue() : e.getMessage(),
                e.getStack(),
                e.getStackSymbolicated()
        );
        return new IssueEventResponse(
                e.getId(), e.getIssueId(), e.getEventId(), e.getAppKey(), e.getUserId(), e.getSessionId(),
                exception,
                parseJsonField(e.getBreadcrumbs()),
                parseJsonField(e.getTags()),
                parseJsonField(e.getDevice()),
                e.getPlatform(), e.getRelease(), e.getEnvironment(),
                e.getSdkName(), e.getSdkVersion(), e.getCreatedAt()
        );
    }

    private Object parseJsonField(String json) {
        if (json == null || json.isBlank()) return null;
        try {
            return objectMapper.readValue(json, Object.class);
        } catch (Exception ex) {
            return json;
        }
    }

    private String toJson(Object obj) {
        if (obj == null) return null;
        try {
            return objectMapper.writeValueAsString(obj);
        } catch (JsonProcessingException e) {
            return obj.toString();
        }
    }

    private String truncate(String s, int maxLen) {
        if (s == null) return "";
        return s.length() <= maxLen ? s : s.substring(0, maxLen);
    }

    private LocalDateTime parseDate(String dateStr) {
        if (dateStr == null || dateStr.isBlank()) return null;
        try { return LocalDate.parse(dateStr).atStartOfDay(); }
        catch (Exception e) { return null; }
    }
}