package com.zy.acs.manager.core.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.zy.acs.common.utils.GsonUtils;
import com.zy.acs.framework.common.Cools;
import com.zy.acs.framework.common.SnowflakeIdWorker;
import com.zy.acs.manager.core.domain.Lane;
import com.zy.acs.manager.manager.entity.Code;
import com.zy.acs.manager.manager.service.CodeService;
import com.zy.acs.manager.manager.service.RouteService;
import com.zy.acs.manager.system.service.ConfigService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;
import java.util.stream.Collectors;

/**
 * Created by vincent on 10/25/2024
 */
@Slf4j
@Service
public class LaneService {

    private boolean initialized = Boolean.FALSE;

    private final List<Lane> lanes = new ArrayList<>();

    private final Map<String, List<String>> adjacencyCodeMap = new HashMap<>();

    @Autowired
    private CodeService codeService;
    @Autowired
    private RouteService routeService;
    @Autowired
    private SnowflakeIdWorker snowflakeIdWorker;
    @Autowired
    private ConfigService configService;

    public Boolean isInitialized() {
        return this.initialized;
    }

    public Lane search(String codeData) {
        if (Cools.isEmpty(codeData) || !this.initialized) {
            return null;
        }
        for (Lane lane : this.lanes) {
            if (lane.getCodes().contains(codeData)) {
                return lane;
            }
        }
        return null;
    }

    @PostConstruct
    public synchronized void init() {
        log.info("the rcs system is starting to initialize lane data...");
        List<Code> codeList = codeService.list(new LambdaQueryWrapper<Code>().eq(Code::getStatus, 1));

        this.fillAdjacencyCodeMap(codeList);

        this.generateLane(codeList.stream().map(Code::getData).collect(Collectors.toList()));

        this.mergeDeadEndLane();

        this.deleteInteractionPoint();

        this.filterLanesWithFewPoints();

        this.generateLaneHash();

        this.initialized = Boolean.TRUE;
        log.info("the lane data initialization has been completed in rcs system.");

        System.out.println(GsonUtils.toJson(this.lanes));
    }

    private void fillAdjacencyCodeMap(List<Code> codeList) {
        for (Code code : codeList) {
            List<Long> adjacencyNode = routeService.getAdjacencyNode(code.getId());
            this.adjacencyCodeMap.put(code.getData(), adjacencyNode.stream().map(node -> (
                    codeService.getById(node).getData()
            )).collect(Collectors.toList()));
        }
    }

    private void generateLane(List<String> codeDataList) {
        Set<String> visited = new HashSet<>();

        for (String codeData : codeDataList) {
            if (this.adjacencyCodeMap.get(codeData).size() != 2) {
                List<String> neighbors = this.adjacencyCodeMap.get(codeData);
                for (String neighbor : neighbors) {
                    if (this.adjacencyCodeMap.get(neighbor).size() == 2 && !visited.contains(neighbor)) {
                        Lane lane = new Lane(String.valueOf(snowflakeIdWorker.nextId()).substring(3));
                        lane.getCodes().add(codeData); // 包含起点
                        this.dfsCalcIncludingEnd(codeData, neighbor, lane, visited);
                        this.lanes.add(lane);
                    }
                }
            }
        }

        for (String codeData : codeDataList) {
            if (this.adjacencyCodeMap.get(codeData).size() == 2 && !visited.contains(codeData)) {
                // 检查是否为环路的一部分
                Lane lane = new Lane(String.valueOf(snowflakeIdWorker.nextId()).substring(3));
                this.dfsCalcForLoop(codeData, null, lane, visited);
                this.lanes.add(lane);
            }
        }


    }

    private void dfsCalcIncludingEnd(String start, String current, Lane lane, Set<String> visited) {
        lane.getCodes().add(current);
        visited.add(current);

        List<String> neighbors = this.adjacencyCodeMap.get(current);
        if (neighbors == null || neighbors.isEmpty()) {
            return;
        }

        for (String neighbor : neighbors) {
            if (neighbor.equals(start)) {
                continue;
            }

            if (!visited.contains(neighbor)) {
                int degree = this.adjacencyCodeMap.get(neighbor).size();
                if (degree == 2) {
                    if (this.isSameDirection(current, neighbor, start)) {
                        this.dfsCalcIncludingEnd(current, neighbor, lane, visited);
                    }
                } else {
                    // 终点或拐弯点，包含并停止
                    lane.getCodes().add(neighbor);
                    visited.add(neighbor);
                }
            }
        }
    }

    private void dfsCalcForLoop(String current, String parent, Lane lane, Set<String> visited) {
        lane.getCodes().add(current);
        visited.add(current);

        List<String> neighbors = this.adjacencyCodeMap.get(current);
        if (neighbors == null || neighbors.isEmpty()) {
            return;
        }

        for (String neighbor : neighbors) {
            if (neighbor.equals(parent)) {
                continue;
            }

            if (!visited.contains(neighbor)) {
                int degree = this.adjacencyCodeMap.get(neighbor).size();
                if (degree == 2) {
                    if (this.isSameDirection(current, neighbor, parent)) {
                        this.dfsCalcForLoop(current, neighbor, lane, visited);
                    }
                } else {
                    lane.getCodes().add(neighbor);
                    visited.add(neighbor);
                }
            }
        }
    }

    private boolean isSameDirection(String current, String neighbor, String parent) {
        if (parent == null) {
            return true;
        }

        Code parentCode = codeService.selectByData(parent);
        Code currentCode = codeService.selectByData(current);
        Code neighborCode = codeService.selectByData(neighbor);

        double direction1 = this.calculateDirection(parentCode, currentCode);
        double direction2 = this.calculateDirection(currentCode, neighborCode);
        double angleDifference = Math.abs(direction1 - direction2);

        // 规范化角度差
        angleDifference = Math.min(angleDifference, 2 * Math.PI - angleDifference);

        // 设置角度差阈值为3度
        return angleDifference < Math.toRadians(3);
    }

    /**
     * 计算两个点之间的方向角
     */
    private double calculateDirection(Code from, Code to) {
        double deltaX = to.getX() - from.getX();
        double deltaY = to.getY() - from.getY();
        return Math.atan2(deltaY, deltaX);
    }

    /**
     * 1.explore a dead end lane and checkout end point that is not dead point
     * 2.if this point has two near points and one of those points which not in current lane was also have two near points too
     * 3.then merge above two lane because they can connect each other
     */
    private void mergeDeadEndLane() {
        Iterator<Lane> iterator = this.lanes.iterator();
        while (iterator.hasNext()) {
            Lane lane = iterator.next();
            String[] endPoints = lane.queryEndPoints();
            if (null == endPoints) {
                continue;
            }
            String startPoint = endPoints[0];
            String endPoint = endPoints[1];

            boolean isDeadEndLane = false;
            String deadEndPoint = null;
            Integer anotherPointNearsCount = null;
            if (this.adjacencyCodeMap.get(startPoint).size() == 1) {
                isDeadEndLane = true;
                deadEndPoint = startPoint;
                anotherPointNearsCount = this.adjacencyCodeMap.get(endPoint).size();
            }
            if (this.adjacencyCodeMap.get(endPoint).size() == 1) {
                isDeadEndLane = true;
                deadEndPoint = endPoint;
                anotherPointNearsCount = this.adjacencyCodeMap.get(startPoint).size();
            }

            if (!isDeadEndLane) {
                continue;
            }

            if (anotherPointNearsCount == 2) {
                String anotherPoint = deadEndPoint.equals(startPoint) ? endPoint : startPoint;
                List<String> anotherPointNears = this.adjacencyCodeMap.get(anotherPoint);
                for (String anotherPointNear : anotherPointNears) {
                    if (!lane.getCodes().contains(anotherPointNear) && this.adjacencyCodeMap.get(anotherPointNear).size() == 2) {

                        for (Lane lane0 : lanes) {
                            if (lane0.getCodes().contains(anotherPointNear)) {

                                lane0.getCodes().addAll(lane.getCodes());
                                iterator.remove();

                                lane0.sortUsingDfs(this.adjacencyCodeMap);

                            }
                        }

                    }
                }
            }

        }
    }

    private void deleteInteractionPoint() {
        for (Lane lane : this.lanes) {
            lane.removeInteraction(this.adjacencyCodeMap);
        }
    }

    private void filterLanesWithFewPoints() {
        Integer maxAgvCountInLane = configService.getVal("maxAgvCountInLane", Integer.class);
        this.lanes.removeIf(next -> next.getCodes().size() <= Optional.ofNullable(maxAgvCountInLane).orElse(2));
    }


    private void generateLaneHash() {
        for (Lane lane : this.lanes) {
            String hashCode = generateDigest(lane.getCodes());
            lane.setHashCode(hashCode);
        }
    }

    public static String generateDigest(List<String> list) {
        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance("SHA-256");
        } catch (NoSuchAlgorithmException e) {
            log.error("generateDigest", e);
            throw new RuntimeException(e);
        }
        String combined = list.stream().sorted().collect(Collectors.joining(","));
        byte[] hashBytes = md.digest(combined.getBytes());

        StringBuilder sb = new StringBuilder();
        for (byte b : hashBytes) {
            sb.append(String.format("%02x", b));
        }
        return sb.toString();
    }

}