package com.baiyue.lastleg.appointmentplanning;

import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import com.baiyue.common.core.api.PageResult;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import jakarta.validation.constraints.*;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.server.ResponseStatusException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HexFormat;
import java.nio.charset.StandardCharsets;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.Instant;
import java.util.Set;

@Service
public class AppointmentFollowupService {
    private final AppointmentSourceService sources;
    private final AppointmentFollowupMapper mapper;
    private final ObjectMapper json;
    private final AppointmentContainerService containers;
    public AppointmentFollowupService(AppointmentSourceService sources, AppointmentFollowupMapper mapper, ObjectMapper json,
                                      AppointmentContainerService containers) {
        this.sources = sources; this.mapper = mapper; this.json = json; this.containers = containers;
    }
    public record Save(@NotBlank @Size(max=32) String stage, @Min(0) int expectedVersion,
                       @NotBlank @Size(max=64) String idempotencyKey,
                       @Size(max=200) String contactedParty, @NotBlank @Size(max=1000) String result,
                       @Size(max=500) String nextAction, LocalDate followupDate) { }
    public record Record(String stage, int version, String contactedParty, String result, String nextAction,
                         LocalDate followupDate, String operatorName, Instant createdAt) { }
    public record History(PageResult<Record> history, java.util.Map<String,Integer> versions) { }
    private static final Set<String> STAGES = Set.of("DRAYAGE_CONTACT", "TERMINAL_APPOINTMENT", "WAREHOUSE_RECEIVING", "FBA_RECEIVING");

    public History history(String sourceKey, String customerId, int page, int size) {
        requireCargoKey(sourceKey);
        return history(sourceKey,customerId,page,size,()->sources.resolve(sourceKey,customerId,null));
    }
    public History containerHistory(String containerId,String warehouseId,int page,int size) {
        return history(AppointmentContainerService.subjectKey(containerId,warehouseId),"0",page,size,()->containers.context(containerId,warehouseId));
    }
    private History history(String sourceKey,String customerId,int page,int size,Runnable verifySource) {
        if (page<1 || size<1 || size>100) throw new ResponseStatusException(HttpStatus.BAD_REQUEST,"分页参数无效");
        long total = mapper.count(sourceKey,customerId);
        if (total == 0) verifySource.run();
        var records = mapper.page(sourceKey,customerId,size,(long)(page-1)*size).stream().map(AppointmentFollowupService::view).toList();
        var versions = new java.util.LinkedHashMap<String,Integer>();
        STAGES.stream().sorted().forEach(stage -> versions.put(stage, mapper.version(sourceKey,customerId,stage)));
        return new History(new PageResult<>(records,page,size,total,(total+size-1)/size),versions);
    }

    @Transactional(isolation = org.springframework.transaction.annotation.Isolation.READ_COMMITTED)
    public Record save(String sourceKey, String customerId, Save request, String operatorId, String operatorName) {
        requireCargoKey(sourceKey);
        if(!"FBA_RECEIVING".equals(request.stage())) throw new ResponseStatusException(HttpStatus.BAD_REQUEST,"提柜及接仓事项请进入整柜跟进，避免按货物重复联系");
        return append(sourceKey,customerId,request,operatorId,operatorName,()->{
            var source=sources.resolve(sourceKey,customerId,null);
            return new Subject(source.orderId(),source.canFollowup());
        });
    }
    @Transactional(isolation = org.springframework.transaction.annotation.Isolation.READ_COMMITTED)
    public Record saveContainer(String containerId,String warehouseId,Save request,String operatorId,String operatorName) {
        String key=AppointmentContainerService.subjectKey(containerId,warehouseId);
        boolean allowed=warehouseId==null ? Set.of("DRAYAGE_CONTACT","TERMINAL_APPOINTMENT").contains(request.stage()) : "WAREHOUSE_RECEIVING".equals(request.stage());
        if(!allowed) throw new ResponseStatusException(HttpStatus.BAD_REQUEST,"请选择对应柜次或接仓点的跟进事项");
        return append(key,"0",request,operatorId,operatorName,()->{
            var context=containers.context(containerId,warehouseId);
            return new Subject(null,context.canFollowup());
        });
    }
    private record Subject(Long orderId,boolean canFollowup) { }
    private Record append(String sourceKey,String customerId,Save request,String operatorId,String operatorName,
                          java.util.function.Supplier<Subject> resolve) {
        if (!STAGES.contains(request.stage())) throw new ResponseStatusException(HttpStatus.BAD_REQUEST,"请选择有效跟进事项");
        if (request.followupDate()!=null && (request.nextAction()==null || request.nextAction().isBlank())) {
            throw new ResponseStatusException(HttpStatus.BAD_REQUEST,"设置跟进日期时请填写下一步安排");
        }
        final String hash;
        try { hash = HexFormat.of().formatHex(MessageDigest.getInstance("SHA-256").digest((customerId+"\n"+operatorId+"\n"+json.writeValueAsString(request)).getBytes(StandardCharsets.UTF_8))); }
        catch (JsonProcessingException | NoSuchAlgorithmException error) { throw new IllegalStateException("无法保存跟进请求",error); }
        var existing = mapper.command(sourceKey,customerId,request.stage(),request.idempotencyKey());
        if (existing!=null) {
            if (!hash.equals(existing.getRequestHash())) throw new ResponseStatusException(HttpStatus.CONFLICT,"重复请求内容不一致，请核对跟进记录");
            return view(existing);
        }
        var source = resolve.get();
        if (!source.canFollowup()) throw new ResponseStatusException(HttpStatus.CONFLICT,"当前来源仅可查看，请先核对承运状态");
        if (mapper.version(sourceKey,customerId,request.stage())!=request.expectedVersion()) throw new ResponseStatusException(HttpStatus.CONFLICT,"跟进记录已更新，请重新读取后提交");
        var value = new AppointmentFollowup(); value.setId(IdWorker.getId()); value.setSourceOrderId(source.orderId()); value.setSourceKey(sourceKey); value.setCustomerId(customerId);
        value.setStage(request.stage()); value.setVersion(request.expectedVersion()+1); value.setContactedParty(clean(request.contactedParty()));
        value.setResult(request.result().trim()); value.setNextAction(clean(request.nextAction())); value.setFollowupDate(request.followupDate());
        value.setOperatorId(operatorId); value.setOperatorName(clean(operatorName)); value.setCommandKey(request.idempotencyKey());
        value.setRequestHash(hash);
        // Return the same precision that DATETIME(3) can persist, including the first response.
        value.setCreatedAt(LocalDateTime.now(ZoneOffset.UTC).truncatedTo(java.time.temporal.ChronoUnit.MILLIS));
        try { mapper.insert(value); }
        catch (org.springframework.dao.DuplicateKeyException conflict) {
            var raced = mapper.command(sourceKey,customerId,request.stage(),request.idempotencyKey());
            if (raced!=null && hash.equals(raced.getRequestHash())) return view(raced);
            throw new ResponseStatusException(HttpStatus.CONFLICT,"跟进记录已更新或请求内容冲突，请重新读取",conflict);
        }
        return view(value);
    }
    private static String clean(String value) { return value==null || value.isBlank() ? null : value.trim(); }
    private static void requireCargoKey(String sourceKey) {
        if(sourceKey==null || !(sourceKey.startsWith("ORDER:") || sourceKey.startsWith("BOOKING:")))
            throw new ResponseStatusException(HttpStatus.BAD_REQUEST,"请选择有效货物来源");
    }
    private static Record view(AppointmentFollowup row) {
        return new Record(row.getStage(),row.getVersion(),row.getContactedParty(),row.getResult(),row.getNextAction(),row.getFollowupDate(),row.getOperatorName(),row.getCreatedAt().toInstant(ZoneOffset.UTC));
    }
}