package com.kaidi.oa.web;

import com.kaidi.oa.common.ApiException;
import com.kaidi.oa.common.ApiResp;
import com.kaidi.oa.common.Money;
import com.kaidi.oa.common.NotFoundException;
import com.kaidi.oa.domain.FertPkgMaterialLedger;
import com.kaidi.oa.repository.FertPkgMaterialLedgerRepository;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
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.time.Instant;
import java.time.LocalDate;
import java.util.ArrayList;
import java.util.List;

/**
 * 生物质肥料制造中心·包装物独立台账（需求 §6，审计 PARTIAL[low]）。
 *
 * 补全缺口：包装物库（编织袋/标签/吨袋）独立台账实体，与成品批次明细关联管理，库位管理。
 *
 * 端点：
 * <ul>
 *   <li>GET /fert-pkg-material-ledger：列表（可按 status/packSpec/keyword 筛选）；</li>
 *   <li>POST /fert-pkg-material-ledger：建档（pkgCode 唯一约束 → 409）；</li>
 *   <li>PUT /fert-pkg-material-ledger/{id}：更新描述字段；</li>
 *   <li>DELETE /fert-pkg-material-ledger/{id}：删除；</li>
 *   <li>POST /fert-pkg-material-ledger/{id}/inbound：入库（增 qty，记录入库日期）；</li>
 *   <li>POST /fert-pkg-material-ledger/{id}/issue：领用出库（减 qty，绑定成品批次）；</li>
 *   <li>POST /fert-pkg-material-ledger/{id}/return：退库；</li>
 *   <li>GET /fert-pkg-material-ledger/low-stock：低库存预警（qty &lt;= safetyStock）；</li>
 *   <li>GET /fert-pkg-material-ledger/summary：各包装规格汇总统计；</li>
 * </ul>
 */
@RestController
@RequestMapping("/api/oa/fert-pkg-material-ledger")
public class FertPkgMaterialLedgerController {

    private final FertPkgMaterialLedgerRepository repo;

    public FertPkgMaterialLedgerController(FertPkgMaterialLedgerRepository repo) {
        this.repo = repo;
    }

    // -------- 列表 --------

    @GetMapping
    public ApiResp<List<FertPkgMaterialLedger>> list(
            @RequestParam(required = false) String status,
            @RequestParam(required = false) String packSpec,
            @RequestParam(required = false) String keyword) {
        List<FertPkgMaterialLedger> all;
        if (keyword != null && !keyword.isBlank()) {
            all = repo.findByPkgNameContaining(keyword.trim());
        } else if (packSpec != null && !packSpec.isBlank()) {
            all = repo.findByPackSpec(packSpec.trim());
        } else if (status != null && !status.isBlank()) {
            all = repo.findByStatus(status.trim());
        } else {
            all = repo.findAll();
        }
        return ApiResp.ok(all);
    }

    @GetMapping("/{id}")
    public ApiResp<FertPkgMaterialLedger> get(@PathVariable Long id) {
        return ApiResp.ok(find(id));
    }

    // -------- 建档/更新/删除 --------

    public record PkgRequest(
            String pkgCode, String pkgName, String spec, String bin, String unit,
            Double qty, Double safetyStock, Double unitCost, String supplier,
            String packSpec, String remark) {
    }

    @PostMapping
    @Transactional
    public ApiResp<FertPkgMaterialLedger> create(@RequestBody PkgRequest req) {
        if (req.pkgName() == null || req.pkgName().isBlank()) {
            throw new ApiException(400, "包装物名称(pkgName) 不能为空");
        }
        String code = (req.pkgCode() == null || req.pkgCode().isBlank())
                ? "PKG-" + (repo.count() + 1) : req.pkgCode().trim();
        if (repo.findByPkgCode(code).isPresent()) {
            throw new ApiException(409, "包装物编码已存在：" + code);
        }
        FertPkgMaterialLedger e = new FertPkgMaterialLedger();
        e.setPkgCode(code);
        e.setPkgName(req.pkgName().trim());
        e.setSpec(req.spec());
        e.setWarehouse("包装物库");
        e.setBin(req.bin() == null || req.bin().isBlank() ? "A货架-01" : req.bin().trim());
        e.setUnit(req.unit() == null || req.unit().isBlank() ? "条" : req.unit().trim());
        BigDecimal qty = Money.of(req.qty());
        e.setQty(qty);
        e.setSafetyStock(Money.of(req.safetyStock()));
        e.setUnitCost(Money.of(req.unitCost()));
        e.setSupplier(req.supplier());
        e.setPackSpec(req.packSpec());
        e.setLastInboundDate(LocalDate.now().toString());
        e.setLastMoveType(qty.signum() > 0 ? "入库" : null);
        e.setStatus(evalStatus(qty, Money.of(req.safetyStock())));
        e.setRemark(req.remark());
        e.setCreatedAt(Instant.now());
        return ApiResp.ok(repo.save(e));
    }

    @PutMapping("/{id}")
    @Transactional
    public ApiResp<FertPkgMaterialLedger> update(@PathVariable Long id, @RequestBody PkgRequest req) {
        FertPkgMaterialLedger e = find(id);
        if (req.pkgName() != null && !req.pkgName().isBlank()) e.setPkgName(req.pkgName().trim());
        if (req.spec() != null) e.setSpec(req.spec());
        if (req.bin() != null && !req.bin().isBlank()) e.setBin(req.bin().trim());
        if (req.unit() != null && !req.unit().isBlank()) e.setUnit(req.unit().trim());
        if (req.safetyStock() != null) e.setSafetyStock(Money.of(req.safetyStock()));
        if (req.unitCost() != null) e.setUnitCost(Money.of(req.unitCost()));
        if (req.supplier() != null) e.setSupplier(req.supplier());
        if (req.packSpec() != null) e.setPackSpec(req.packSpec());
        if (req.remark() != null) e.setRemark(req.remark());
        e.setStatus(evalStatus(e.getQty(), e.getSafetyStock()));
        return ApiResp.ok(repo.save(e));
    }

    @DeleteMapping("/{id}")
    @Transactional
    public ApiResp<Void> delete(@PathVariable Long id) {
        repo.delete(find(id));
        return ApiResp.ok();
    }

    // -------- 出入库操作 --------

    public record MoveRequest(Double qty, String linkedBatchNo, String operator, String remark) {
    }

    /** 入库：增 qty，记录入库日期。 */
    @PostMapping("/{id}/inbound")
    @Transactional
    public ApiResp<FertPkgMaterialLedger> inbound(@PathVariable Long id, @RequestBody MoveRequest req) {
        FertPkgMaterialLedger e = find(id);
        BigDecimal q = requirePositive(req.qty());
        e.setQty(Money.of(e.getQty().add(q)));
        e.setLastInboundDate(LocalDate.now().toString());
        e.setLastMoveType("入库");
        e.setStatus(evalStatus(e.getQty(), e.getSafetyStock()));
        return ApiResp.ok(repo.save(e));
    }

    /** 领用出库：减 qty，绑定成品批次号（补全与成品明细关联管理缺口）。 */
    @PostMapping("/{id}/issue")
    @Transactional
    public ApiResp<FertPkgMaterialLedger> issue(@PathVariable Long id, @RequestBody MoveRequest req) {
        FertPkgMaterialLedger e = find(id);
        BigDecimal q = requirePositive(req.qty());
        if (q.compareTo(e.getQty()) > 0) {
            throw new ApiException(400, "领用数量(" + q + ")超过库存(" + e.getQty() + ")");
        }
        e.setQty(Money.of(e.getQty().subtract(q)));
        if (req.linkedBatchNo() != null && !req.linkedBatchNo().isBlank()) {
            e.setLinkedBatchNo(req.linkedBatchNo().trim());
        }
        e.setLastMoveType("领用");
        e.setStatus(evalStatus(e.getQty(), e.getSafetyStock()));
        return ApiResp.ok(repo.save(e));
    }

    /** 退库：增 qty，清除成品批次关联。 */
    @PostMapping("/{id}/return")
    @Transactional
    public ApiResp<FertPkgMaterialLedger> returnToStock(@PathVariable Long id, @RequestBody MoveRequest req) {
        FertPkgMaterialLedger e = find(id);
        BigDecimal q = requirePositive(req.qty());
        e.setQty(Money.of(e.getQty().add(q)));
        e.setLastMoveType("退库");
        e.setStatus(evalStatus(e.getQty(), e.getSafetyStock()));
        return ApiResp.ok(repo.save(e));
    }

    // -------- 低库存预警 --------

    public record LowStockRow(Long id, String pkgCode, String pkgName, String spec, String packSpec,
                               BigDecimal qty, BigDecimal safetyStock, String unit, String bin) {
    }

    @GetMapping("/low-stock")
    public ApiResp<List<LowStockRow>> lowStock() {
        List<LowStockRow> out = new ArrayList<>();
        for (FertPkgMaterialLedger e : repo.findAll()) {
            if (e.getSafetyStock() != null && e.getSafetyStock().signum() > 0
                    && e.getQty().compareTo(e.getSafetyStock()) <= 0) {
                out.add(new LowStockRow(e.getId(), e.getPkgCode(), e.getPkgName(),
                        e.getSpec(), e.getPackSpec(), e.getQty(), e.getSafetyStock(),
                        e.getUnit(), e.getBin()));
            }
        }
        return ApiResp.ok(out);
    }

    // -------- 规格汇总统计 --------

    public record PkgSummaryRow(String packSpec, BigDecimal totalQty, int itemCount, BigDecimal totalValue) {
    }

    @GetMapping("/summary")
    public ApiResp<List<PkgSummaryRow>> summary() {
        java.util.Map<String, BigDecimal[]> map = new java.util.LinkedHashMap<>();
        for (FertPkgMaterialLedger e : repo.findAll()) {
            String key = e.getPackSpec() == null ? "未指定" : e.getPackSpec();
            BigDecimal[] arr = map.computeIfAbsent(key, k -> new BigDecimal[]{BigDecimal.ZERO, BigDecimal.ZERO, BigDecimal.ZERO});
            arr[0] = arr[0].add(e.getQty());
            arr[1] = arr[1].add(BigDecimal.ONE);
            BigDecimal val = e.getQty().multiply(e.getUnitCost() == null ? BigDecimal.ZERO : e.getUnitCost());
            arr[2] = arr[2].add(val);
        }
        List<PkgSummaryRow> out = new ArrayList<>();
        for (java.util.Map.Entry<String, BigDecimal[]> entry : map.entrySet()) {
            out.add(new PkgSummaryRow(entry.getKey(), Money.of(entry.getValue()[0]),
                    entry.getValue()[1].intValue(), Money.of(entry.getValue()[2])));
        }
        return ApiResp.ok(out);
    }

    // -------- helpers --------

    private FertPkgMaterialLedger find(Long id) {
        return repo.findById(id).orElseThrow(() -> new NotFoundException("包装物台账记录不存在：" + id));
    }

    private static BigDecimal requirePositive(Double v) {
        BigDecimal q = Money.of(v);
        if (q.signum() <= 0) throw new ApiException(400, "数量必须大于 0");
        return q;
    }

    private static String evalStatus(BigDecimal qty, BigDecimal safety) {
        if (qty == null || qty.signum() <= 0) return "已耗尽";
        if (safety != null && safety.signum() > 0 && qty.compareTo(safety) <= 0) return "低库存";
        return "在库";
    }
}