package com.ruoyi.workflow.service.impl;

import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.ruoyi.common.utils.SecurityUtils;
import com.ruoyi.workflow.domain.WorkflowDefinition;
import com.ruoyi.workflow.domain.WorkflowInstance;
import com.ruoyi.workflow.service.IWorkflowEngineService;

/**
 * 工作流引擎Service业务层处理
 * 
 * @author ruoyi
 * @date 2025-12-19
 */
@Service
public class WorkflowEngineServiceImpl implements IWorkflowEngineService 
{
    private static final Logger log = LoggerFactory.getLogger(WorkflowEngineServiceImpl.class);

    private ObjectMapper objectMapper = new ObjectMapper();
    
    // 内存存储（实际应该使用数据库）
    private Map<Long, WorkflowDefinition> workflowDefinitions = new ConcurrentHashMap<>();
    private Map<Long, WorkflowInstance> workflowInstances = new ConcurrentHashMap<>();
    private Map<String, Map<String, Object>> workflowTasks = new ConcurrentHashMap<>();
    private List<Map<String, Object>> workflowHistory = new ArrayList<>();
    
    private Long nextInstanceId = 1L;
    private Long nextDefinitionId = 1L;

    /**
     * 启动工作流实例
     */
    @Override
    public WorkflowInstance startWorkflow(Long definitionId, String businessKey, Map<String, Object> variables)
    {
        try {
            WorkflowDefinition definition = workflowDefinitions.get(definitionId);
            if (definition == null) {
                throw new RuntimeException("工作流定义不存在: " + definitionId);
            }

            WorkflowInstance instance = new WorkflowInstance();
            instance.setInstanceId(nextInstanceId++);
            instance.setDefinitionId(definitionId);
            instance.setInstanceName(definition.getWorkflowName() + "_" + instance.getInstanceId());
            instance.setBusinessKey(businessKey);
            instance.setStartUserId(SecurityUtils.getUserId());
            instance.setStartUserName(SecurityUtils.getUsername());
            instance.setInstanceStatus("RUNNING");
            instance.setCurrentNode("START");
            instance.setStartTime(new Date());
            instance.setPriority(1);

            if (variables != null) {
                instance.setVariablesJson(objectMapper.writeValueAsString(variables));
            }

            workflowInstances.put(instance.getInstanceId(), instance);

            // 记录历史
            recordWorkflowHistory(instance.getInstanceId(), "WORKFLOW_STARTED", 
                                "工作流实例启动", variables);

            log.info("工作流实例启动成功: {}", instance.getInstanceId());
            return instance;

        } catch (Exception e) {
            log.error("启动工作流实例失败: {}", e.getMessage(), e);
            throw new RuntimeException("启动工作流实例失败: " + e.getMessage());
        }
    }

    /**
     * 执行任务
     */
    @Override
    public Map<String, Object> executeTask(Long instanceId, String taskId, String action, Map<String, Object> variables)
    {
        Map<String, Object> result = new HashMap<>();
        
        try {
            WorkflowInstance instance = workflowInstances.get(instanceId);
            if (instance == null) {
                throw new RuntimeException("工作流实例不存在: " + instanceId);
            }

            if (!"RUNNING".equals(instance.getInstanceStatus())) {
                throw new RuntimeException("工作流实例状态不允许执行任务: " + instance.getInstanceStatus());
            }

            // 执行任务逻辑
            String nextNode = determineNextNode(instance.getCurrentNode(), action);
            instance.setCurrentNode(nextNode);

            // 更新变量
            if (variables != null) {
                Map<String, Object> currentVariables = getCurrentVariables(instance);
                currentVariables.putAll(variables);
                instance.setVariablesJson(objectMapper.writeValueAsString(currentVariables));
            }

            // 检查是否完成
            if ("END".equals(nextNode)) {
                instance.setInstanceStatus("COMPLETED");
                instance.setEndTime(new Date());
                if (instance.getStartTime() != null) {
                    instance.setDuration(instance.getEndTime().getTime() - instance.getStartTime().getTime());
                }
            }

            workflowInstances.put(instanceId, instance);

            // 记录历史
            recordWorkflowHistory(instanceId, "TASK_EXECUTED", 
                                "任务执行: " + taskId + " -> " + action, variables);

            result.put("success", true);
            result.put("message", "任务执行成功");
            result.put("nextNode", nextNode);
            result.put("instanceStatus", instance.getInstanceStatus());

            log.info("任务执行成功: 实例={}, 任务={}, 动作={}", instanceId, taskId, action);

        } catch (Exception e) {
            log.error("执行任务失败: {}", e.getMessage(), e);
            result.put("success", false);
            result.put("message", "执行任务失败: " + e.getMessage());
        }

        return result;
    }

    /**
     * 审批任务
     */
    @Override
    public Map<String, Object> approveTask(Long instanceId, String taskId, Long approverId, String decision, String comments)
    {
        Map<String, Object> variables = new HashMap<>();
        variables.put("approverId", approverId);
        variables.put("decision", decision);
        variables.put("comments", comments);
        variables.put("approveTime", new Date());

        return executeTask(instanceId, taskId, decision, variables);
    }

    /**
     * 获取工作流实例状态
     */
    @Override
    public Map<String, Object> getWorkflowStatus(Long instanceId)
    {
        Map<String, Object> status = new HashMap<>();
        
        try {
            WorkflowInstance instance = workflowInstances.get(instanceId);
            if (instance == null) {
                status.put("exists", false);
                status.put("message", "工作流实例不存在");
                return status;
            }

            status.put("exists", true);
            status.put("instanceId", instance.getInstanceId());
            status.put("instanceName", instance.getInstanceName());
            status.put("businessKey", instance.getBusinessKey());
            status.put("status", instance.getInstanceStatus());
            status.put("currentNode", instance.getCurrentNode());
            status.put("startTime", instance.getStartTime());
            status.put("endTime", instance.getEndTime());
            status.put("duration", instance.getDuration());
            status.put("startUser", instance.getStartUserName());

            // 获取当前变量
            Map<String, Object> variables = getCurrentVariables(instance);
            status.put("variables", variables);

        } catch (Exception e) {
            log.error("获取工作流状态失败: {}", e.getMessage(), e);
            status.put("error", e.getMessage());
        }

        return status;
    }

    /**
     * 回滚工作流到指定步骤
     */
    @Override
    public Map<String, Object> rollbackWorkflow(Long instanceId, String targetStep)
    {
        Map<String, Object> result = new HashMap<>();
        
        try {
            WorkflowInstance instance = workflowInstances.get(instanceId);
            if (instance == null) {
                throw new RuntimeException("工作流实例不存在: " + instanceId);
            }

            String previousNode = instance.getCurrentNode();
            instance.setCurrentNode(targetStep);
            instance.setInstanceStatus("RUNNING"); // 重新激活

            workflowInstances.put(instanceId, instance);

            // 记录历史
            Map<String, Object> rollbackInfo = new HashMap<>();
            rollbackInfo.put("fromNode", previousNode);
            rollbackInfo.put("toNode", targetStep);
            recordWorkflowHistory(instanceId, "WORKFLOW_ROLLBACK", 
                                "工作流回滚", rollbackInfo);

            result.put("success", true);
            result.put("message", "工作流回滚成功");
            result.put("fromNode", previousNode);
            result.put("toNode", targetStep);

            log.info("工作流回滚成功: 实例={}, 从{}回滚到{}", instanceId, previousNode, targetStep);

        } catch (Exception e) {
            log.error("工作流回滚失败: {}", e.getMessage(), e);
            result.put("success", false);
            result.put("message", "工作流回滚失败: " + e.getMessage());
        }

        return result;
    }

    /**
     * 定义工作流模板
     */
    @Override
    public WorkflowDefinition defineWorkflowTemplate(Map<String, Object> templateInfo)
    {
        try {
            WorkflowDefinition definition = new WorkflowDefinition();
            definition.setDefinitionId(nextDefinitionId++);
            definition.setWorkflowName((String) templateInfo.get("name"));
            definition.setVersion((String) templateInfo.getOrDefault("version", "1.0"));
            definition.setDescription((String) templateInfo.get("description"));
            definition.setDefinitionJson(objectMapper.writeValueAsString(templateInfo));
            definition.setStatus("0"); // 启用
            definition.setCreator(SecurityUtils.getUsername());
            definition.setPublishTime(new Date());
            definition.setIsDefault("1");

            workflowDefinitions.put(definition.getDefinitionId(), definition);

            log.info("工作流模板定义成功: {}", definition.getWorkflowName());
            return definition;

        } catch (Exception e) {
            log.error("定义工作流模板失败: {}", e.getMessage(), e);
            throw new RuntimeException("定义工作流模板失败: " + e.getMessage());
        }
    }

    /**
     * 分配任务
     */
    @Override
    public Map<String, Object> assignTask(String taskId, Long assigneeId)
    {
        Map<String, Object> result = new HashMap<>();
        
        try {
            Map<String, Object> task = workflowTasks.get(taskId);
            if (task == null) {
                task = new HashMap<>();
            }

            task.put("assigneeId", assigneeId);
            task.put("assignTime", new Date());
            task.put("status", "ASSIGNED");

            workflowTasks.put(taskId, task);

            result.put("success", true);
            result.put("message", "任务分配成功");
            result.put("taskId", taskId);
            result.put("assigneeId", assigneeId);

            log.info("任务分配成功: 任务={}, 分配给={}", taskId, assigneeId);

        } catch (Exception e) {
            log.error("任务分配失败: {}", e.getMessage(), e);
            result.put("success", false);
            result.put("message", "任务分配失败: " + e.getMessage());
        }

        return result;
    }

    /**
     * 任务升级
     */
    @Override
    public Map<String, Object> escalateTask(String taskId, Map<String, Object> escalationRule)
    {
        Map<String, Object> result = new HashMap<>();
        
        try {
            Map<String, Object> task = workflowTasks.get(taskId);
            if (task == null) {
                task = new HashMap<>();
            }

            task.put("escalated", true);
            task.put("escalationRule", escalationRule);
            task.put("escalationTime", new Date());

            // 根据升级规则重新分配
            Long newAssigneeId = (Long) escalationRule.get("escalateToUserId");
            if (newAssigneeId != null) {
                task.put("assigneeId", newAssigneeId);
            }

            workflowTasks.put(taskId, task);

            result.put("success", true);
            result.put("message", "任务升级成功");
            result.put("taskId", taskId);
            result.put("newAssigneeId", newAssigneeId);

            log.info("任务升级成功: 任务={}, 升级到={}", taskId, newAssigneeId);

        } catch (Exception e) {
            log.error("任务升级失败: {}", e.getMessage(), e);
            result.put("success", false);
            result.put("message", "任务升级失败: " + e.getMessage());
        }

        return result;
    }

    /**
     * 查询用户待办任务
     */
    @Override
    public List<Map<String, Object>> getUserTasks(Long userId)
    {
        List<Map<String, Object>> userTasks = new ArrayList<>();
        
        for (Map.Entry<String, Map<String, Object>> entry : workflowTasks.entrySet()) {
            Map<String, Object> task = entry.getValue();
            Long assigneeId = (Long) task.get("assigneeId");
            
            if (userId.equals(assigneeId) && !"COMPLETED".equals(task.get("status"))) {
                Map<String, Object> taskInfo = new HashMap<>(task);
                taskInfo.put("taskId", entry.getKey());
                userTasks.add(taskInfo);
            }
        }

        return userTasks;
    }

    /**
     * 查询工作流实例历史
     */
    @Override
    public List<Map<String, Object>> getWorkflowHistory(Long instanceId)
    {
        List<Map<String, Object>> history = new ArrayList<>();
        
        for (Map<String, Object> record : workflowHistory) {
            if (instanceId.equals(record.get("instanceId"))) {
                history.add(record);
            }
        }

        return history;
    }

    /**
     * 暂停工作流实例
     */
    @Override
    public Map<String, Object> suspendWorkflow(Long instanceId)
    {
        return updateWorkflowStatus(instanceId, "SUSPENDED", "工作流实例已暂停");
    }

    /**
     * 恢复工作流实例
     */
    @Override
    public Map<String, Object> resumeWorkflow(Long instanceId)
    {
        return updateWorkflowStatus(instanceId, "RUNNING", "工作流实例已恢复");
    }

    /**
     * 终止工作流实例
     */
    @Override
    public Map<String, Object> terminateWorkflow(Long instanceId, String reason)
    {
        Map<String, Object> result = updateWorkflowStatus(instanceId, "TERMINATED", "工作流实例已终止");
        
        if ((Boolean) result.get("success")) {
            WorkflowInstance instance = workflowInstances.get(instanceId);
            if (instance != null) {
                instance.setEndTime(new Date());
                if (instance.getStartTime() != null) {
                    instance.setDuration(instance.getEndTime().getTime() - instance.getStartTime().getTime());
                }
                
                // 记录终止原因
                Map<String, Object> terminateInfo = new HashMap<>();
                terminateInfo.put("reason", reason);
                recordWorkflowHistory(instanceId, "WORKFLOW_TERMINATED", 
                                    "工作流实例终止: " + reason, terminateInfo);
            }
        }

        return result;
    }

    /**
     * 获取工作流定义列表
     */
    @Override
    public List<WorkflowDefinition> getWorkflowDefinitions()
    {
        return new ArrayList<>(workflowDefinitions.values());
    }

    /**
     * 部署工作流定义
     */
    @Override
    public Map<String, Object> deployWorkflowDefinition(WorkflowDefinition definition)
    {
        Map<String, Object> result = new HashMap<>();
        
        try {
            if (definition.getDefinitionId() == null) {
                definition.setDefinitionId(nextDefinitionId++);
            }
            
            definition.setPublishTime(new Date());
            workflowDefinitions.put(definition.getDefinitionId(), definition);

            result.put("success", true);
            result.put("message", "工作流定义部署成功");
            result.put("definitionId", definition.getDefinitionId());

            log.info("工作流定义部署成功: {}", definition.getWorkflowName());

        } catch (Exception e) {
            log.error("部署工作流定义失败: {}", e.getMessage(), e);
            result.put("success", false);
            result.put("message", "部署工作流定义失败: " + e.getMessage());
        }

        return result;
    }

    /**
     * 获取工作流统计信息
     */
    @Override
    public Map<String, Object> getWorkflowStatistics(Map<String, Object> params)
    {
        Map<String, Object> statistics = new HashMap<>();
        
        try {
            long totalInstances = workflowInstances.size();
            long runningInstances = workflowInstances.values().stream()
                .filter(instance -> "RUNNING".equals(instance.getInstanceStatus()))
                .count();
            long completedInstances = workflowInstances.values().stream()
                .filter(instance -> "COMPLETED".equals(instance.getInstanceStatus()))
                .count();
            long suspendedInstances = workflowInstances.values().stream()
                .filter(instance -> "SUSPENDED".equals(instance.getInstanceStatus()))
                .count();

            statistics.put("totalInstances", totalInstances);
            statistics.put("runningInstances", runningInstances);
            statistics.put("completedInstances", completedInstances);
            statistics.put("suspendedInstances", suspendedInstances);
            statistics.put("totalDefinitions", workflowDefinitions.size());
            statistics.put("totalTasks", workflowTasks.size());

        } catch (Exception e) {
            log.error("获取工作流统计信息失败: {}", e.getMessage(), e);
            statistics.put("error", e.getMessage());
        }

        return statistics;
    }

    // 辅助方法

    private String determineNextNode(String currentNode, String action) {
        // 简化的节点流转逻辑
        switch (currentNode) {
            case "START":
                return "TASK1";
            case "TASK1":
                return "APPROVE".equals(action) ? "TASK2" : "END";
            case "TASK2":
                return "END";
            default:
                return "END";
        }
    }

    private Map<String, Object> getCurrentVariables(WorkflowInstance instance) {
        try {
            if (instance.getVariablesJson() != null) {
                return objectMapper.readValue(instance.getVariablesJson(), Map.class);
            }
        } catch (Exception e) {
            log.warn("解析工作流变量失败: {}", e.getMessage());
        }
        return new HashMap<>();
    }

    private void recordWorkflowHistory(Long instanceId, String eventType, String description, Map<String, Object> data) {
        Map<String, Object> historyRecord = new HashMap<>();
        historyRecord.put("instanceId", instanceId);
        historyRecord.put("eventType", eventType);
        historyRecord.put("description", description);
        historyRecord.put("eventTime", new Date());
        historyRecord.put("data", data);
        historyRecord.put("userId", SecurityUtils.getUserId());
        historyRecord.put("userName", SecurityUtils.getUsername());
        
        workflowHistory.add(historyRecord);
    }

    private Map<String, Object> updateWorkflowStatus(Long instanceId, String status, String message) {
        Map<String, Object> result = new HashMap<>();
        
        try {
            WorkflowInstance instance = workflowInstances.get(instanceId);
            if (instance == null) {
                throw new RuntimeException("工作流实例不存在: " + instanceId);
            }

            String previousStatus = instance.getInstanceStatus();
            instance.setInstanceStatus(status);
            workflowInstances.put(instanceId, instance);

            // 记录历史
            Map<String, Object> statusInfo = new HashMap<>();
            statusInfo.put("fromStatus", previousStatus);
            statusInfo.put("toStatus", status);
            recordWorkflowHistory(instanceId, "STATUS_CHANGED", message, statusInfo);

            result.put("success", true);
            result.put("message", message);
            result.put("previousStatus", previousStatus);
            result.put("currentStatus", status);

            log.info("工作流状态更新成功: 实例={}, 状态={}→{}", instanceId, previousStatus, status);

        } catch (Exception e) {
            log.error("更新工作流状态失败: {}", e.getMessage(), e);
            result.put("success", false);
            result.put("message", "更新工作流状态失败: " + e.getMessage());
        }

        return result;
    }
}