package com.kaidi.oa.web;

import com.kaidi.oa.common.ApiException;
import com.kaidi.oa.common.ApiResp;
import com.kaidi.oa.common.NotFoundException;
import com.kaidi.oa.domain.CustomerVisit;
import com.kaidi.oa.repository.CustomerRepository;
import com.kaidi.oa.repository.CustomerVisitRepository;
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.time.Instant;
import java.time.LocalDate;
import java.time.format.DateTimeParseException;
import java.time.temporal.ChronoUnit;
import java.util.ArrayList;
import java.util.List;

/**
 * 市场部·客户拜访纪要与跟进提醒（支持移动端现场录入）。覆盖拜访纪要 CRUD、按客户/拜访人筛选、
 * 标记跟进完成（POST /{id}/mark-followed），以及跟进提醒聚合（GET /reminders：把未完成且
 * 下次跟进日落在窗口内的拜访按 逾期 / 今日 / 临近 分级，杜绝跟进遗漏）。
 *
 * 读口含客户跟进明细（属销售线索类业务），写口默认受 default-deny(ADMIN/APPROVER) 保护。
 */
@RestController
@RequestMapping("/api/oa/customer-visits")
public class CustomerVisitController {

    private final CustomerVisitRepository visitRepo;
    private final CustomerRepository customerRepo;

    public CustomerVisitController(CustomerVisitRepository visitRepo,
                                   CustomerRepository customerRepo) {
        this.visitRepo = visitRepo;
        this.customerRepo = customerRepo;
    }

    @GetMapping
    public ApiResp<List<CustomerVisit>> list(@RequestParam(required = false) Long customerId,
                                             @RequestParam(required = false) String owner) {
        if (customerId != null) {
            return ApiResp.ok(visitRepo.findByCustomerId(customerId));
        }
        if (owner != null && !owner.isBlank()) {
            return ApiResp.ok(visitRepo.findByOwner(owner));
        }
        return ApiResp.ok(visitRepo.findAll());
    }

    @GetMapping("/{id}")
    public ApiResp<CustomerVisit> get(@PathVariable Long id) {
        return ApiResp.ok(visitRepo.findById(id)
                .orElseThrow(() -> new NotFoundException("customer visit not found: " + id)));
    }

    public record VisitRequest(
            Long customerId, String customerName, String visitType, String contactPerson,
            String visitDate, String summary, String nextFollowDate, String nextPlan,
            Boolean followed, String orgUnit, String location, String owner) {
    }

    @PostMapping
    public ApiResp<CustomerVisit> create(@RequestBody VisitRequest req) {
        if (req.customerId() == null) {
            throw new ApiException(400, "客户(customerId) 不能为空");
        }
        // 校验客户存在，杜绝悬挂引用。
        var customer = customerRepo.findById(req.customerId())
                .orElseThrow(() -> new ApiException(400, "客户不存在：" + req.customerId()));
        if (req.summary() == null || req.summary().isBlank()) {
            throw new ApiException(400, "拜访纪要(summary) 不能为空");
        }
        CustomerVisit v = new CustomerVisit();
        v.setCustomerId(req.customerId());
        v.setCustomerName(req.customerName() == null || req.customerName().isBlank()
                ? customer.getName() : req.customerName());
        v.setVisitType(req.visitType() == null || req.visitType().isBlank() ? "上门" : req.visitType());
        v.setContactPerson(req.contactPerson());
        v.setVisitDate(req.visitDate() == null || req.visitDate().isBlank()
                ? LocalDate.now().toString() : req.visitDate());
        v.setSummary(req.summary());
        v.setNextFollowDate(req.nextFollowDate());
        v.setNextPlan(req.nextPlan());
        v.setFollowed(req.followed() != null ? req.followed() : Boolean.FALSE);
        v.setOrgUnit(req.orgUnit());
        v.setLocation(req.location());
        v.setOwner(req.owner());
        v.setCreatedAt(Instant.now());
        return ApiResp.ok(visitRepo.save(v));
    }

    @PatchMapping("/{id}")
    public ApiResp<CustomerVisit> update(@PathVariable Long id, @RequestBody VisitRequest req) {
        CustomerVisit v = visitRepo.findById(id)
                .orElseThrow(() -> new NotFoundException("customer visit not found: " + id));
        if (req.customerName() != null && !req.customerName().isBlank()) v.setCustomerName(req.customerName());
        if (req.visitType() != null && !req.visitType().isBlank()) v.setVisitType(req.visitType());
        if (req.contactPerson() != null) v.setContactPerson(req.contactPerson());
        if (req.visitDate() != null) v.setVisitDate(req.visitDate());
        if (req.summary() != null && !req.summary().isBlank()) v.setSummary(req.summary());
        if (req.nextFollowDate() != null) v.setNextFollowDate(req.nextFollowDate());
        if (req.nextPlan() != null) v.setNextPlan(req.nextPlan());
        if (req.followed() != null) v.setFollowed(req.followed());
        if (req.orgUnit() != null) v.setOrgUnit(req.orgUnit());
        if (req.location() != null) v.setLocation(req.location());
        if (req.owner() != null) v.setOwner(req.owner());
        return ApiResp.ok(visitRepo.save(v));
    }

    @DeleteMapping("/{id}")
    public ApiResp<Void> delete(@PathVariable Long id) {
        if (!visitRepo.existsById(id)) {
            throw new NotFoundException("customer visit not found: " + id);
        }
        visitRepo.deleteById(id);
        return ApiResp.ok(null);
    }

    /** POST /{id}/mark-followed → 标记本次跟进已完成（从提醒列表移除）。 */
    @PostMapping("/{id}/mark-followed")
    public ApiResp<CustomerVisit> markFollowed(@PathVariable Long id) {
        CustomerVisit v = visitRepo.findById(id)
                .orElseThrow(() -> new NotFoundException("customer visit not found: " + id));
        v.setFollowed(Boolean.TRUE);
        return ApiResp.ok(visitRepo.save(v));
    }

    // ---------- 跟进提醒聚合 ----------

    public record Reminder(Long visitId, Long customerId, String customerName, String owner,
                           String nextFollowDate, String nextPlan, long daysToFollow, String level) {
    }

    /**
     * GET /reminders → 跟进提醒：未完成(followed=false) 且下次跟进日落在 [今天-逾期, 今天+days]
     * 的拜访。level：逾期 / 今日 / 临近(<=3天) / 关注(<=days)。按距离升序，逾期最前。
     */
    @GetMapping("/reminders")
    public ApiResp<List<Reminder>> reminders(@RequestParam(required = false, defaultValue = "14") int days) {
        LocalDate today = LocalDate.now();
        List<Reminder> out = new ArrayList<>();
        for (CustomerVisit v : visitRepo.findByFollowed(Boolean.FALSE)) {
            LocalDate next = parseDateOrNull(v.getNextFollowDate());
            if (next == null) {
                continue;
            }
            long daysTo = ChronoUnit.DAYS.between(today, next);
            if (daysTo > days) {
                continue;
            }
            String level = daysTo < 0 ? "逾期" : daysTo == 0 ? "今日" : daysTo <= 3 ? "临近" : "关注";
            out.add(new Reminder(v.getId(), v.getCustomerId(), v.getCustomerName(), v.getOwner(),
                    v.getNextFollowDate(), v.getNextPlan(), daysTo, level));
        }
        out.sort((a, b) -> Long.compare(a.daysToFollow(), b.daysToFollow()));
        return ApiResp.ok(out);
    }

    private static LocalDate parseDateOrNull(String s) {
        if (s == null || s.isBlank()) {
            return null;
        }
        try {
            String t = s.trim();
            return LocalDate.parse(t.substring(0, Math.min(10, t.length())));
        } catch (DateTimeParseException | IndexOutOfBoundsException e) {
            return null;
        }
    }
}