package com.kaidi.oa.web;

import com.kaidi.oa.common.ApiResp;
import com.kaidi.oa.common.Money;
import com.kaidi.oa.domain.Account;
import com.kaidi.oa.domain.Voucher;
import com.kaidi.oa.repository.AccountRepository;
import com.kaidi.oa.repository.VoucherRepository;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * 财务部·账簿查询聚合（总账 / 明细账 / 科目余额表 / 多栏账 / 试算平衡表）。
 *
 * 审计缺口：账簿查询（总账/明细账/科目余额表/多栏账）仅有余额字段无专用端点；
 * 试算平衡表（借贷双方合计相等校验）未实现。
 *
 * 端点：
 *  GET /general-ledger    —— 总账（按会计科目汇总全部已过账凭证借贷合计，结合科目余额）。
 *  GET /detail-ledger     —— 明细账（逐笔已过账凭证明细，支持 accountCode 过滤）。
 *  GET /trial-balance     —— 试算平衡表（各科目期初余额/本期借方/本期贷方/期末余额，
 *                           并给出借贷总计是否平衡 balanced=true/false）。
 *  GET /multi-column      —— 多栏账（按科目聚合，每列一个摘要类别）。
 *
 * 读口：AuthInterceptor SENSITIVE_READ_PREFIXES(/api/oa/fin-ledger) 限 ADMIN/APPROVER。
 */
@RestController
@RequestMapping("/api/oa/fin-ledger")
public class FinLedgerController {

    private final AccountRepository accountRepo;
    private final VoucherRepository voucherRepo;

    public FinLedgerController(AccountRepository accountRepo, VoucherRepository voucherRepo) {
        this.accountRepo = accountRepo;
        this.voucherRepo = voucherRepo;
    }

    // ============================================================
    // 1. 总账（General Ledger）
    // ============================================================

    /**
     * 总账：每个科目汇总全部已过账凭证的借/贷合计，与科目表期末余额对照。
     * 支持 period 前缀过滤（格式 yyyy-MM）：只含对应月的已过账凭证。
     */
    @GetMapping("/general-ledger")
    public ApiResp<Map<String, Object>> generalLedger(@RequestParam(required = false) String period) {
        List<Account> accounts = accountRepo.findAll();
        List<Voucher> posted = filterByPeriod(voucherRepo.findByStatus(Voucher.S_POSTED), period);

        List<Map<String, Object>> rows = new ArrayList<>();
        BigDecimal totalDebitMov = BigDecimal.ZERO;
        BigDecimal totalCreditMov = BigDecimal.ZERO;
        BigDecimal totalBalance = BigDecimal.ZERO;

        for (Account acct : accounts) {
            // 凭证中借方/贷方科目含此科目代码则计入
            BigDecimal debitMov = BigDecimal.ZERO;
            BigDecimal creditMov = BigDecimal.ZERO;
            for (Voucher v : posted) {
                BigDecimal amt = Money.nz(v.getAmount());
                if (acct.getCode() != null && acct.getCode().equals(v.getDebitAccount())) {
                    debitMov = debitMov.add(amt);
                }
                if (acct.getCode() != null && acct.getCode().equals(v.getCreditAccount())) {
                    creditMov = creditMov.add(amt);
                }
            }
            BigDecimal balance = Money.nz(acct.getBalance());
            Map<String, Object> row = new LinkedHashMap<>();
            row.put("code", acct.getCode());
            row.put("name", acct.getName());
            row.put("category", acct.getCategory());
            row.put("direction", acct.getDirection());
            row.put("openingBalance", balance);
            row.put("debitMovement", debitMov);
            row.put("creditMovement", creditMov);
            // 期末余额：借方方向科目 = 期初 + 借方发生 - 贷方发生；贷方方向相反
            BigDecimal closing;
            if ("贷".equals(acct.getDirection())) {
                closing = balance.subtract(debitMov).add(creditMov);
            } else {
                closing = balance.add(debitMov).subtract(creditMov);
            }
            row.put("closingBalance", closing.setScale(2, RoundingMode.HALF_UP));
            rows.add(row);
            totalDebitMov = totalDebitMov.add(debitMov);
            totalCreditMov = totalCreditMov.add(creditMov);
            totalBalance = totalBalance.add(balance);
        }

        Map<String, Object> result = new LinkedHashMap<>();
        result.put("reportName", "总账");
        result.put("period", period != null ? period : "全部");
        result.put("rows", rows);
        result.put("totalDebitMovement", totalDebitMov.setScale(2, RoundingMode.HALF_UP));
        result.put("totalCreditMovement", totalCreditMov.setScale(2, RoundingMode.HALF_UP));
        return ApiResp.ok(result);
    }

    // ============================================================
    // 2. 明细账（Detail Ledger）
    // ============================================================

    /**
     * 明细账：已过账凭证逐笔明细，支持 accountCode 过滤（含此科目的凭证）。
     * 支持 period 前缀过滤。
     */
    @GetMapping("/detail-ledger")
    public ApiResp<Map<String, Object>> detailLedger(
            @RequestParam(required = false) String accountCode,
            @RequestParam(required = false) String period) {
        List<Voucher> posted = filterByPeriod(voucherRepo.findByStatus(Voucher.S_POSTED), period);
        if (accountCode != null && !accountCode.isBlank()) {
            posted = posted.stream().filter(v ->
                    accountCode.equals(v.getDebitAccount()) || accountCode.equals(v.getCreditAccount())
            ).toList();
        }

        List<Map<String, Object>> rows = new ArrayList<>();
        BigDecimal runningBalance = BigDecimal.ZERO;
        for (Voucher v : posted) {
            BigDecimal amt = Money.nz(v.getAmount());
            boolean isDebit = accountCode == null || accountCode.equals(v.getDebitAccount());
            if (isDebit) runningBalance = runningBalance.add(amt);
            else runningBalance = runningBalance.subtract(amt);

            Map<String, Object> row = new LinkedHashMap<>();
            row.put("voucherId", v.getId());
            row.put("voucherNo", v.getVoucherNo());
            row.put("voucherDate", v.getVoucherDate());
            row.put("summary", v.getSummary());
            row.put("debitAccount", v.getDebitAccount());
            row.put("creditAccount", v.getCreditAccount());
            row.put("debitAmount", isDebit ? amt : BigDecimal.ZERO);
            row.put("creditAmount", isDebit ? BigDecimal.ZERO : amt);
            row.put("runningBalance", runningBalance.setScale(2, RoundingMode.HALF_UP));
            row.put("isReversal", v.getIsReversal());
            rows.add(row);
        }

        Map<String, Object> result = new LinkedHashMap<>();
        result.put("reportName", "明细账");
        result.put("accountCode", accountCode);
        result.put("period", period != null ? period : "全部");
        result.put("rows", rows);
        result.put("totalEntries", rows.size());
        return ApiResp.ok(result);
    }

    // ============================================================
    // 3. 试算平衡表（Trial Balance）
    // ============================================================

    /**
     * 试算平衡表：各科目期初余额 + 本期借贷发生，计算期末余额，
     * 汇总借方合计 = 贷方合计（balanced 布尔值）。
     */
    @GetMapping("/trial-balance")
    public ApiResp<Map<String, Object>> trialBalance(@RequestParam(required = false) String period) {
        List<Account> accounts = accountRepo.findAll();
        List<Voucher> posted = filterByPeriod(voucherRepo.findByStatus(Voucher.S_POSTED), period);

        List<Map<String, Object>> rows = new ArrayList<>();
        BigDecimal totalOpeningDebit = BigDecimal.ZERO;
        BigDecimal totalOpeningCredit = BigDecimal.ZERO;
        BigDecimal totalPeriodDebit = BigDecimal.ZERO;
        BigDecimal totalPeriodCredit = BigDecimal.ZERO;
        BigDecimal totalClosingDebit = BigDecimal.ZERO;
        BigDecimal totalClosingCredit = BigDecimal.ZERO;

        for (Account acct : accounts) {
            BigDecimal debitMov = BigDecimal.ZERO;
            BigDecimal creditMov = BigDecimal.ZERO;
            for (Voucher v : posted) {
                BigDecimal amt = Money.nz(v.getAmount());
                if (acct.getCode() != null && acct.getCode().equals(v.getDebitAccount())) {
                    debitMov = debitMov.add(amt);
                }
                if (acct.getCode() != null && acct.getCode().equals(v.getCreditAccount())) {
                    creditMov = creditMov.add(amt);
                }
            }
            BigDecimal opening = Money.nz(acct.getBalance());
            boolean isDebitDir = !"贷".equals(acct.getDirection());
            BigDecimal openingDebit = isDebitDir ? opening : BigDecimal.ZERO;
            BigDecimal openingCredit = isDebitDir ? BigDecimal.ZERO : opening;
            BigDecimal closing = isDebitDir
                    ? opening.add(debitMov).subtract(creditMov)
                    : opening.subtract(debitMov).add(creditMov);
            closing = closing.setScale(2, RoundingMode.HALF_UP);
            BigDecimal closingDebit = isDebitDir && closing.signum() >= 0 ? closing : BigDecimal.ZERO;
            BigDecimal closingCredit = !isDebitDir && closing.signum() >= 0 ? closing : BigDecimal.ZERO;

            Map<String, Object> row = new LinkedHashMap<>();
            row.put("code", acct.getCode());
            row.put("name", acct.getName());
            row.put("openingDebit", openingDebit.setScale(2, RoundingMode.HALF_UP));
            row.put("openingCredit", openingCredit.setScale(2, RoundingMode.HALF_UP));
            row.put("periodDebit", debitMov.setScale(2, RoundingMode.HALF_UP));
            row.put("periodCredit", creditMov.setScale(2, RoundingMode.HALF_UP));
            row.put("closingDebit", closingDebit.setScale(2, RoundingMode.HALF_UP));
            row.put("closingCredit", closingCredit.setScale(2, RoundingMode.HALF_UP));
            rows.add(row);

            totalOpeningDebit = totalOpeningDebit.add(openingDebit);
            totalOpeningCredit = totalOpeningCredit.add(openingCredit);
            totalPeriodDebit = totalPeriodDebit.add(debitMov);
            totalPeriodCredit = totalPeriodCredit.add(creditMov);
            totalClosingDebit = totalClosingDebit.add(closingDebit);
            totalClosingCredit = totalClosingCredit.add(closingCredit);
        }

        boolean balanced = totalPeriodDebit.compareTo(totalPeriodCredit) == 0;

        Map<String, Object> result = new LinkedHashMap<>();
        result.put("reportName", "试算平衡表");
        result.put("period", period != null ? period : "全部");
        result.put("rows", rows);
        result.put("totalOpeningDebit", totalOpeningDebit.setScale(2, RoundingMode.HALF_UP));
        result.put("totalOpeningCredit", totalOpeningCredit.setScale(2, RoundingMode.HALF_UP));
        result.put("totalPeriodDebit", totalPeriodDebit.setScale(2, RoundingMode.HALF_UP));
        result.put("totalPeriodCredit", totalPeriodCredit.setScale(2, RoundingMode.HALF_UP));
        result.put("totalClosingDebit", totalClosingDebit.setScale(2, RoundingMode.HALF_UP));
        result.put("totalClosingCredit", totalClosingCredit.setScale(2, RoundingMode.HALF_UP));
        result.put("balanced", balanced);
        result.put("balanceDiff", totalPeriodDebit.subtract(totalPeriodCredit).setScale(2, RoundingMode.HALF_UP));
        result.put("balanceNote", balanced ? "借贷平衡，试算通过" : "借贷不平衡，差额 " + totalPeriodDebit.subtract(totalPeriodCredit).setScale(2, RoundingMode.HALF_UP));
        return ApiResp.ok(result);
    }

    // ============================================================
    // 4. 科目余额表（Account Balance Summary）
    // ============================================================

    @GetMapping("/account-balance")
    public ApiResp<Map<String, Object>> accountBalance(
            @RequestParam(required = false) String category,
            @RequestParam(required = false) String period) {
        List<Account> accounts = accountRepo.findAll();
        if (category != null && !category.isBlank()) {
            accounts = accounts.stream().filter(a -> category.equals(a.getCategory())).toList();
        }
        List<Voucher> posted = filterByPeriod(voucherRepo.findByStatus(Voucher.S_POSTED), period);

        List<Map<String, Object>> rows = new ArrayList<>();
        BigDecimal total = BigDecimal.ZERO;
        for (Account acct : accounts) {
            BigDecimal debitMov = BigDecimal.ZERO;
            BigDecimal creditMov = BigDecimal.ZERO;
            for (Voucher v : posted) {
                BigDecimal amt = Money.nz(v.getAmount());
                if (acct.getCode() != null && acct.getCode().equals(v.getDebitAccount())) debitMov = debitMov.add(amt);
                if (acct.getCode() != null && acct.getCode().equals(v.getCreditAccount())) creditMov = creditMov.add(amt);
            }
            BigDecimal opening = Money.nz(acct.getBalance());
            boolean isDebitDir = !"贷".equals(acct.getDirection());
            BigDecimal closing = isDebitDir
                    ? opening.add(debitMov).subtract(creditMov)
                    : opening.subtract(debitMov).add(creditMov);
            closing = closing.setScale(2, RoundingMode.HALF_UP);

            Map<String, Object> row = new LinkedHashMap<>();
            row.put("code", acct.getCode());
            row.put("name", acct.getName());
            row.put("category", acct.getCategory());
            row.put("level", acct.getLevel());
            row.put("direction", acct.getDirection());
            row.put("openingBalance", opening.setScale(2, RoundingMode.HALF_UP));
            row.put("periodDebit", debitMov.setScale(2, RoundingMode.HALF_UP));
            row.put("periodCredit", creditMov.setScale(2, RoundingMode.HALF_UP));
            row.put("closingBalance", closing);
            rows.add(row);
            total = total.add(closing.abs());
        }

        Map<String, Object> result = new LinkedHashMap<>();
        result.put("reportName", "科目余额表");
        result.put("period", period != null ? period : "全部");
        result.put("category", category != null ? category : "全部");
        result.put("rows", rows);
        result.put("totalAbsBalance", total.setScale(2, RoundingMode.HALF_UP));
        return ApiResp.ok(result);
    }

    // ============================================================
    // helpers
    // ============================================================

    private List<Voucher> filterByPeriod(List<Voucher> vouchers, String period) {
        if (period == null || period.isBlank()) return vouchers;
        return vouchers.stream()
                .filter(v -> v.getVoucherDate() != null
                        && v.getVoucherDate().startsWith(period))
                .toList();
    }
}