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.DesignChangeOrder;
import com.kaidi.oa.domain.DesignProject;
import com.kaidi.oa.repository.DesignChangeOrderRepository;
import com.kaidi.oa.repository.DesignProjectRepository;
import com.kaidi.oa.service.NotificationService;
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.PatchMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
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.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * 设计研究中心·规划设计部 §3 设计变更管理（变更单工作流）。覆盖变更申请→评估→按等级生成
 * 审批链→会签审批→执行（版本更新+自动提醒受影响专业）→变更台账统计。
 *
 * 状态机：草稿 → 评估中(submit) → 审批中 → 已批准(approve) → 已实施(implement)；任一审批环节
 * 可 已驳回(reject)。审批链按变更等级自动生成：
 *   重大 → 专业负责人 / 项目总工 / 成本部 / 甲方代表（多方会签）；
 *   一般 → 专业负责人 / 项目总工；
 *   轻微 → 专业负责人。
 *
 * 写口含成本影响额，默认受 AuthInterceptor 的 default-deny(ADMIN/APPROVER) 保护，
 * 读口含金额应登记进 SENSITIVE_READ_PREFIXES（见 sharedFileSnippets）。
 */
@RestController
@RequestMapping("/api/oa/design-change-orders")
public class DesignChangeOrderController {

    private final DesignChangeOrderRepository repo;
    private final DesignProjectRepository projectRepo;
    private final NotificationService notificationService;

    public DesignChangeOrderController(DesignChangeOrderRepository repo,
                                       DesignProjectRepository projectRepo,
                                       NotificationService notificationService) {
        this.repo = repo;
        this.projectRepo = projectRepo;
        this.notificationService = notificationService;
    }

    @GetMapping
    public ApiResp<List<DesignChangeOrder>> list(@RequestParam(required = false) String status,
                                                 @RequestParam(required = false) Long projectId) {
        if (projectId != null) {
            return ApiResp.ok(repo.findByProjectId(projectId));
        }
        if (status != null && !status.isBlank()) {
            return ApiResp.ok(repo.findByStatus(status));
        }
        return ApiResp.ok(repo.findAll());
    }

    @GetMapping("/{id}")
    public ApiResp<DesignChangeOrder> get(@PathVariable Long id) {
        return ApiResp.ok(repo.findById(id)
                .orElseThrow(() -> new NotFoundException("design change order not found: " + id)));
    }

    public record ChangeRequest(
            Long projectId, String projectName, String docName, String title, String source,
            String level, String reason, String impactScope, String affectedDisciplines,
            Double costImpact, Integer scheduleImpactDays, String fromVersion, String applicant) {
    }

    @PostMapping
    public ApiResp<DesignChangeOrder> create(@RequestBody ChangeRequest req) {
        if (req.title() == null || req.title().isBlank()) {
            throw new ApiException(400, "变更标题不能为空");
        }
        DesignChangeOrder c = new DesignChangeOrder();
        c.setCode("BG-" + (repo.count() + 1));
        if (req.projectId() != null) {
            DesignProject p = projectRepo.findById(req.projectId()).orElse(null);
            if (p != null) {
                c.setProjectId(p.getId());
                c.setProjectCode(p.getCode());
                c.setProjectName(p.getName());
            }
        }
        if (c.getProjectName() == null) {
            c.setProjectName(req.projectName());
        }
        c.setDocName(req.docName());
        c.setTitle(req.title());
        c.setSource(req.source());
        c.setLevel(normLevel(req.level()));
        c.setReason(req.reason());
        c.setImpactScope(req.impactScope());
        c.setAffectedDisciplines(req.affectedDisciplines());
        c.setCostImpact(Money.of(req.costImpact()));
        c.setScheduleImpactDays(req.scheduleImpactDays());
        c.setFromVersion(req.fromVersion());
        c.setApplicant(req.applicant());
        c.setStatus("草稿");
        c.setCreatedAt(Instant.now());
        return ApiResp.ok(repo.save(c));
    }

    @PatchMapping("/{id}")
    public ApiResp<DesignChangeOrder> update(@PathVariable Long id, @RequestBody ChangeRequest req) {
        DesignChangeOrder c = repo.findById(id)
                .orElseThrow(() -> new NotFoundException("design change order not found: " + id));
        if (!"草稿".equals(c.getStatus())) {
            throw new ApiException(409, "仅草稿状态可编辑（当前：" + c.getStatus() + "）");
        }
        if (req.projectName() != null) c.setProjectName(req.projectName());
        if (req.docName() != null) c.setDocName(req.docName());
        if (req.title() != null && !req.title().isBlank()) c.setTitle(req.title());
        if (req.source() != null) c.setSource(req.source());
        if (req.level() != null) c.setLevel(normLevel(req.level()));
        if (req.reason() != null) c.setReason(req.reason());
        if (req.impactScope() != null) c.setImpactScope(req.impactScope());
        if (req.affectedDisciplines() != null) c.setAffectedDisciplines(req.affectedDisciplines());
        if (req.costImpact() != null) c.setCostImpact(Money.of(req.costImpact()));
        if (req.scheduleImpactDays() != null) c.setScheduleImpactDays(req.scheduleImpactDays());
        if (req.fromVersion() != null) c.setFromVersion(req.fromVersion());
        if (req.applicant() != null) c.setApplicant(req.applicant());
        return ApiResp.ok(repo.save(c));
    }

    /**
     * 提交评估并进入审批：草稿 → 评估中 → 审批中（按变更等级自动生成会签审批链）。
     * 同时自动计算审批链——这一步把"变更等级→不同审批链"落到工作流上。
     */
    @PostMapping("/{id}/submit")
    public ApiResp<DesignChangeOrder> submit(@PathVariable Long id) {
        DesignChangeOrder c = repo.findById(id)
                .orElseThrow(() -> new NotFoundException("design change order not found: " + id));
        if (!"草稿".equals(c.getStatus()) && !"已驳回".equals(c.getStatus())) {
            throw new ApiException(409, "仅草稿/已驳回可提交审批（当前：" + c.getStatus() + "）");
        }
        c.setApprovalChain(chainFor(c.getLevel()));
        c.setStatus("审批中");
        c.setDecisionNote(null);
        return ApiResp.ok(repo.save(c));
    }

    public record DecisionRequest(String note) {
    }

    /** 审批通过：审批中 → 已批准。 */
    @PostMapping("/{id}/approve")
    public ApiResp<DesignChangeOrder> approve(@PathVariable Long id, @RequestBody(required = false) DecisionRequest req) {
        DesignChangeOrder c = repo.findById(id)
                .orElseThrow(() -> new NotFoundException("design change order not found: " + id));
        if (!"审批中".equals(c.getStatus())) {
            throw new ApiException(409, "仅审批中可审批通过（当前：" + c.getStatus() + "）");
        }
        c.setStatus("已批准");
        if (req != null && req.note() != null) {
            c.setDecisionNote(req.note());
        }
        return ApiResp.ok(repo.save(c));
    }

    /** 审批驳回：审批中 → 已驳回（可重新提交）。 */
    @PostMapping("/{id}/reject")
    public ApiResp<DesignChangeOrder> reject(@PathVariable Long id, @RequestBody(required = false) DecisionRequest req) {
        DesignChangeOrder c = repo.findById(id)
                .orElseThrow(() -> new NotFoundException("design change order not found: " + id));
        if (!"审批中".equals(c.getStatus())) {
            throw new ApiException(409, "仅审批中可驳回（当前：" + c.getStatus() + "）");
        }
        c.setStatus("已驳回");
        c.setDecisionNote(req == null ? null : req.note());
        return ApiResp.ok(repo.save(c));
    }

    public record ImplementRequest(String toVersion) {
    }

    /**
     * 执行变更：已批准 → 已实施。强制更新图纸版本（fromVersion→toVersion，未给则自动 +0.1），
     * 落实施日期。返回体里带"受影响专业自动提醒"清单（前端据此提示通知其他专业）。
     */
    @PostMapping("/{id}/implement")
    @Transactional
    public ApiResp<DesignChangeOrder> implement(@PathVariable Long id, @RequestBody(required = false) ImplementRequest req) {
        DesignChangeOrder c = repo.findById(id)
                .orElseThrow(() -> new NotFoundException("design change order not found: " + id));
        if (!"已批准".equals(c.getStatus())) {
            throw new ApiException(409, "仅已批准的变更可执行（当前：" + c.getStatus() + "）");
        }
        String to = req == null ? null : req.toVersion();
        if (to == null || to.isBlank()) {
            to = bumpVersion(c.getFromVersion());
        }
        c.setToVersion(to);
        c.setStatus("已实施");
        c.setImplementedDate(LocalDate.now().toString());
        DesignChangeOrder saved = repo.save(c);

        // §3 缺口补完：实施后对受影响专业逐一发送真实站内通知（Message 持久化），
        // 而非仅在响应体 affectedDisciplines 字段提示，解决"无真实推送"缺口。
        String disciplines = c.getAffectedDisciplines();
        if (disciplines != null && !disciplines.isBlank()) {
            String title = "【设计变更通知】" + safe(c.getTitle());
            String body = "变更单「" + safe(c.getCode()) + "」已实施，图纸版本已从 "
                    + safe(c.getFromVersion()) + " 更新至 " + to
                    + "。受影响专业：" + disciplines + "，请相关专业负责人核实本专业图纸并做对应调整。";
            for (String disc : disciplines.split("[,，]+")) {
                String recipient = disc.trim();
                if (!recipient.isBlank()) {
                    notificationService.notify(recipient, "设计变更", title, body,
                            "DesignChangeOrder", c.getId());
                }
            }
        }
        return ApiResp.ok(saved);
    }

    @DeleteMapping("/{id}")
    public ApiResp<Void> delete(@PathVariable Long id) {
        DesignChangeOrder c = repo.findById(id)
                .orElseThrow(() -> new NotFoundException("design change order not found: " + id));
        if ("已实施".equals(c.getStatus())) {
            throw new ApiException(409, "已实施的变更已进台账，不可删除");
        }
        repo.deleteById(id);
        return ApiResp.ok(null);
    }

    // ---------- 变更台账统计 ----------

    public record LedgerRow(String key, int count, double costImpact, int scheduleImpactDays) {
    }

    public record Ledger(List<LedgerRow> bySource, List<LedgerRow> byLevel,
                         int total, int implemented, double totalCostImpact, int totalScheduleDays) {
    }

    /**
     * 变更台账：按来源 / 按等级汇总变更数、成本影响合计、工期影响合计。这是 §3"生成变更台账，
     * 支持按项目/时间/变更原因统计分析"的只读聚合。projectId 给定时只统计该项目。
     */
    @GetMapping("/ledger")
    public ApiResp<Ledger> ledger(@RequestParam(required = false) Long projectId) {
        List<DesignChangeOrder> all = projectId != null ? repo.findByProjectId(projectId) : repo.findAll();
        Map<String, BigDecimal[]> bySource = new LinkedHashMap<>();
        Map<String, BigDecimal[]> byLevel = new LinkedHashMap<>();
        BigDecimal totalCost = BigDecimal.ZERO;
        int totalDays = 0;
        int implemented = 0;
        for (DesignChangeOrder c : all) {
            BigDecimal cost = Money.nz(c.getCostImpact());
            int days = c.getScheduleImpactDays() == null ? 0 : c.getScheduleImpactDays();
            accumulate(bySource, c.getSource() == null ? "未分类" : c.getSource(), cost, days);
            accumulate(byLevel, c.getLevel() == null ? "未分级" : c.getLevel(), cost, days);
            totalCost = Money.add(totalCost, cost);
            totalDays += days;
            if ("已实施".equals(c.getStatus())) {
                implemented++;
            }
        }
        return ApiResp.ok(new Ledger(toRows(bySource), toRows(byLevel),
                all.size(), implemented, totalCost.doubleValue(), totalDays));
    }

    private void accumulate(Map<String, BigDecimal[]> map, String key, BigDecimal cost, int days) {
        BigDecimal[] acc = map.computeIfAbsent(key, k -> new BigDecimal[]{BigDecimal.ZERO, BigDecimal.ZERO, BigDecimal.ZERO});
        acc[0] = acc[0].add(BigDecimal.ONE);
        acc[1] = Money.add(acc[1], cost);
        acc[2] = acc[2].add(BigDecimal.valueOf(days));
    }

    private List<LedgerRow> toRows(Map<String, BigDecimal[]> map) {
        List<LedgerRow> rows = new ArrayList<>();
        for (Map.Entry<String, BigDecimal[]> e : map.entrySet()) {
            BigDecimal[] v = e.getValue();
            rows.add(new LedgerRow(e.getKey(), v[0].intValue(), v[1].doubleValue(), v[2].intValue()));
        }
        return rows;
    }

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

    private static String normLevel(String level) {
        if (level == null || level.isBlank()) {
            return "一般";
        }
        return level;
    }

    /** 按变更等级生成会签审批链。 */
    private static String chainFor(String level) {
        if ("重大".equals(level)) {
            return "专业负责人,项目总工,成本部,甲方代表";
        }
        if ("轻微".equals(level)) {
            return "专业负责人";
        }
        return "专业负责人,项目总工";
    }

    // ---------- §3 成本影响自动估算 ----------

    /**
     * §3 缺口补完：变更成本影响自动估算（从成本数据库/项目预算联动，不再只靠人工填写）。
     *
     * 逻辑：取项目 budget（设计预算）×变更等级系数 → 估算 costImpact 建议值（元）。
     *   重大：预算×5%；一般：预算×1%；轻微：预算×0.3%。
     * 真实场景下此处应接成本数据库/BIM工程量清单API；当前接设计项目预算做近似估算。
     * 前端调此接口后将建议值回填 costImpact 字段，用户仍可手动覆盖。
     */
    @GetMapping("/estimate-cost-impact")
    public ApiResp<Map<String, Object>> estimateCostImpact(
            @RequestParam(required = false) Long projectId,
            @RequestParam(required = false) String level) {
        BigDecimal budget = BigDecimal.ZERO;
        String projectName = "";
        if (projectId != null) {
            DesignProject p = projectRepo.findById(projectId).orElse(null);
            if (p != null) {
                budget = Money.nz(p.getBudget());
                projectName = p.getName();
            }
        }
        // 系数
        double ratio;
        String normalizedLevel = level == null ? "一般" : level;
        switch (normalizedLevel) {
            case "重大" -> ratio = 0.05;
            case "轻微" -> ratio = 0.003;
            default -> ratio = 0.01;
        }
        BigDecimal estimate = budget.multiply(BigDecimal.valueOf(ratio)).setScale(2, java.math.RoundingMode.HALF_UP);

        LinkedHashMap<String, Object> result = new LinkedHashMap<>();
        result.put("projectId", projectId);
        result.put("projectName", projectName);
        result.put("projectBudget", budget.doubleValue());
        result.put("level", normalizedLevel);
        result.put("ratio", ratio);
        result.put("estimatedCostImpact", estimate.doubleValue());
        result.put("note", "估算值 = 设计预算 × 等级系数（重大5%/一般1%/轻微0.3%）；用户可手动覆盖");
        return ApiResp.ok(result);
    }

    private static String safe(String s) {
        return s == null ? "" : s;
    }

    /** 版本号 +0.1（如 v1.0 → v1.1；无前导 v 也兼容；不可解析则回退 v1.1）。 */
    private static String bumpVersion(String from) {
        if (from == null || from.isBlank()) {
            return "v1.1";
        }
        String s = from.trim();
        boolean hasV = s.startsWith("v") || s.startsWith("V");
        String num = hasV ? s.substring(1) : s;
        try {
            double d = Double.parseDouble(num);
            double next = Math.round((d + 0.1) * 10.0) / 10.0;
            String body = next == Math.rint(next) ? String.valueOf((int) next) + ".0" : String.valueOf(next);
            return (hasV ? "v" : "") + body;
        } catch (NumberFormatException e) {
            return "v1.1";
        }
    }
}