package com.sb.web.account.service;

import com.sb.web.account.dto.AccountEntryRequest;
import com.sb.web.account.dto.AccountTagRequest;
import com.sb.web.account.dto.BudgetRequest;
import com.sb.web.account.dto.CategoryRequest;
import com.sb.web.account.dto.QuickEntryRequest;
import com.sb.web.account.dto.RecurringRequest;
import com.sb.web.account.dto.RestoreRequest;
import com.sb.web.account.dto.WalletRequest;
import com.sb.web.account.mapper.BackupMapper;
import com.sb.web.common.exception.ApiException;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;

/**
 * 데이터 가져오기(복구) — 기존 데이터를 전부 삭제하고 백업(이름 기준)을 새로 재생성한다.
 * 전체를 한 트랜잭션으로 처리해 중간 실패 시 롤백(기존 데이터 보존)된다.
 * ※ 투자 종목/매매내역은 백업에 포함되지 않아 복구 시 삭제된다(평가액 계좌 자체는 복원).
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class BackupService {

    private final BackupMapper backupMapper;
    private final AccountService accountService;
    private final CategoryService categoryService;
    private final RecurringService recurringService;
    private final BudgetService budgetService;
    private final QuickEntryService quickEntryService;

    @Transactional
    public void restore(Long memberId, RestoreRequest req) {
        if (isEmpty(req)) {
            throw new ApiException(HttpStatus.BAD_REQUEST, "복구할 데이터가 비어 있습니다. 백업 파일을 확인해주세요.");
        }

        // 1) 기존 데이터 전부 삭제 (FK 안전 순서)
        backupMapper.deleteEntryTags(memberId);
        backupMapper.deleteEntries(memberId);
        backupMapper.deleteRecurrings(memberId);
        backupMapper.deleteBudgets(memberId);
        backupMapper.deleteBudgetIncome(memberId);
        backupMapper.deleteQuickEntries(memberId);
        backupMapper.deleteInvestTrades(memberId);
        backupMapper.deleteInvestHoldings(memberId);
        backupMapper.deleteCategories(memberId);
        backupMapper.deleteTags(memberId);
        backupMapper.deleteWallets(memberId);

        // 2) 계좌 → 원본 id(oldId) → 새 id (같은 이름 계좌가 있어도 정확)
        Map<Long, Long> walletMap = new HashMap<>();
        if (req.getWallets() != null) {
            for (RestoreRequest.Wal w : req.getWallets()) {
                if (w == null || w.getName() == null) continue;
                WalletRequest wr = new WalletRequest();
                wr.setType(w.getType());
                wr.setName(w.getName());
                wr.setIssuer(w.getIssuer());
                wr.setAccountNumber(w.getAccountNumber());
                wr.setCardType(w.getCardType());
                wr.setOpeningBalance(w.getOpeningBalance());
                wr.setOpeningDate(w.getOpeningDate());
                wr.setCurrentValue(w.getCurrentValue());
                Long newId = accountService.createWallet(wr, memberId).getId();
                if (w.getOldId() != null) walletMap.put(w.getOldId(), newId);
            }
        }

        // 3) 태그 → 이름→새 ID
        Map<String, Long> tagMap = new HashMap<>();
        if (req.getTags() != null) {
            for (String name : req.getTags()) {
                if (name == null || name.isBlank()) continue;
                AccountTagRequest tr = new AccountTagRequest();
                tr.setName(name.trim());
                tagMap.put(name.trim(), accountService.createTag(tr, memberId).getId());
            }
        }

        // 4) 분류 — 대분류 먼저, 소분류는 부모 이름으로 매핑 ("TYPE|name" → id)
        Map<String, Long> catMap = new HashMap<>();
        if (req.getCategories() != null) {
            for (RestoreRequest.Cat c : req.getCategories()) {
                if (c.getName() == null || (c.getParent() != null && !c.getParent().isBlank())) continue;
                CategoryRequest cr = new CategoryRequest();
                cr.setType(c.getType());
                cr.setName(c.getName());
                catMap.put(key(c.getType(), c.getName()), categoryService.create(cr, memberId).getId());
            }
            for (RestoreRequest.Cat c : req.getCategories()) {
                if (c.getName() == null || c.getParent() == null || c.getParent().isBlank()) continue;
                CategoryRequest cr = new CategoryRequest();
                cr.setType(c.getType());
                cr.setName(c.getName());
                cr.setParentId(catMap.get(key(c.getType(), c.getParent())));
                categoryService.create(cr, memberId);
            }
        }

        // 5) 내역
        if (req.getEntries() != null) {
            for (RestoreRequest.Entry e : req.getEntries()) {
                if (e.getEntryDate() == null || e.getType() == null) continue;
                Long wid = walletMap.get(e.getWalletId());
                Long twid = walletMap.get(e.getToWalletId());
                if (badTransfer(e.getType(), wid, twid)) continue; // 이체 계좌가 없거나 같으면 건너뜀
                AccountEntryRequest er = new AccountEntryRequest();
                er.setEntryDate(e.getEntryDate());
                er.setType(e.getType());
                er.setCategory(e.getCategory());
                er.setAmount(e.getAmount());
                er.setMemo(e.getMemo());
                er.setWalletId(wid);
                er.setToWalletId(twid);
                er.setInstallmentMonths(e.getInstallmentMonths());
                if (e.getTags() != null) {
                    er.setTagIds(e.getTags().stream().map(tagMap::get).filter(Objects::nonNull).toList());
                }
                accountService.create(er, memberId);
            }
        }

        // 6) 고정지출
        if (req.getRecurrings() != null) {
            for (RestoreRequest.Recur r : req.getRecurrings()) {
                if (r.getTitle() == null) continue;
                Long wid = walletMap.get(r.getWalletId());
                Long twid = walletMap.get(r.getToWalletId());
                if (badTransfer(r.getType(), wid, twid)) continue;
                RecurringRequest rr = new RecurringRequest();
                rr.setTitle(r.getTitle());
                rr.setType(r.getType());
                rr.setAmount(r.getAmount());
                rr.setCategory(r.getCategory());
                rr.setMemo(r.getMemo());
                rr.setWalletId(wid);
                rr.setToWalletId(twid);
                rr.setFrequency(r.getFrequency());
                rr.setDayOfMonth(r.getDayOfMonth());
                rr.setDayOfWeek(r.getDayOfWeek());
                rr.setMonthOfYear(r.getMonthOfYear());
                rr.setStartDate(r.getStartDate());
                rr.setEndDate(r.getEndDate());
                rr.setActive(r.getActive() == null || r.getActive());
                recurringService.create(rr, memberId);
            }
        }

        // 7) 예산 — 복구 시 현재 월 예산으로 등록(백업엔 월 정보 없음)
        if (req.getBudgets() != null) {
            java.time.LocalDate today = java.time.LocalDate.now();
            for (BudgetRequest b : req.getBudgets()) {
                if (b == null || b.getCategory() == null) continue;
                budgetService.create(b, memberId, today.getYear(), today.getMonthValue());
            }
        }

        // 8) 자주 쓰는 내역
        if (req.getQuickEntries() != null) {
            for (RestoreRequest.Quick q : req.getQuickEntries()) {
                if (q.getType() == null) continue;
                QuickEntryRequest qr = new QuickEntryRequest();
                qr.setLabel(q.getLabel());
                qr.setType(q.getType());
                qr.setCategory(q.getCategory());
                qr.setAmount(q.getAmount());
                qr.setMemo(q.getMemo());
                qr.setWalletId(walletMap.get(q.getWalletId()));
                quickEntryService.create(qr, memberId);
            }
        }

        log.info("[restore] member={} wallets={} entries={} restored",
                memberId, walletMap.size(), req.getEntries() == null ? 0 : req.getEntries().size());
    }

    private static String key(String type, String name) {
        return type + "|" + name;
    }

    /** 이체인데 출금/입금 계좌가 없거나 같으면 복구에서 제외(검증 오류로 전체 롤백 방지) */
    private static boolean badTransfer(String type, Long walletId, Long toWalletId) {
        return "TRANSFER".equals(type) && (walletId == null || toWalletId == null || walletId.equals(toWalletId));
    }

    private boolean isEmpty(RestoreRequest r) {
        return empty(r.getWallets()) && empty(r.getCategories()) && empty(r.getTags())
                && empty(r.getEntries()) && empty(r.getRecurrings()) && empty(r.getBudgets())
                && empty(r.getQuickEntries());
    }

    private boolean empty(List<?> l) {
        return l == null || l.isEmpty();
    }
}