namespace Admin.NET.Plugin.ApprovalFlow.Service;

/// <summary>
/// 审批流程统计服务（P3-15 节点级统计）
/// </summary>
[ApiDescriptionSettings(ApprovalFlowConst.GroupName, Order = 50)]
public class FlowStatisticsService : IDynamicApiController, ITransient
{
    private readonly SqlSugarRepository<ApprovalFlowInstance> _instanceRep;
    private readonly SqlSugarRepository<ApprovalFlowTask> _taskRep;
    private readonly SqlSugarRepository<ApprovalFlowCompletedNode> _completedNodeRep;
    private readonly SqlSugarRepository<ApprovalFlowLog> _logRep;
    private readonly SqlSugarRepository<ApprovalFlow> _flowRep;
    private readonly SqlSugarRepository<ApprovalBizType> _bizTypeRep;

    public FlowStatisticsService(
        SqlSugarRepository<ApprovalFlowInstance> instanceRep,
        SqlSugarRepository<ApprovalFlowTask> taskRep,
        SqlSugarRepository<ApprovalFlowCompletedNode> completedNodeRep,
        SqlSugarRepository<ApprovalFlowLog> logRep,
        SqlSugarRepository<ApprovalFlow> flowRep,
        SqlSugarRepository<ApprovalBizType> bizTypeRep)
    {
        _instanceRep = instanceRep;
        _taskRep = taskRep;
        _completedNodeRep = completedNodeRep;
        _logRep = logRep;
        _flowRep = flowRep;
        _bizTypeRep = bizTypeRep;
    }

    /// <summary>
    /// 概览卡片 + 逐日趋势图
    /// </summary>
    [HttpPost]
    [ApiDescriptionSettings(Name = "Overview")]
    [DisplayName("审批概览")]
    public async Task<FlowOverviewOutput> Overview(FlowStatisticsInput input)
    {
        var (start, end) = NormalizeRange(input);
        var instances = await BuildInstanceQuery(input)
            .Select(i => new InstanceLite { Id = i.Id, Status = i.Status, StartTime = i.StartTime, EndTime = i.EndTime })
            .ToListAsync();

        var total = instances.Count;
        var completed = instances.Count(i => i.Status == FlowInstanceStatusEnum.Approved);
        var completedDurations = instances
            .Where(i => i.Status == FlowInstanceStatusEnum.Approved && i.EndTime.HasValue)
            .Select(i => (decimal)(i.EndTime!.Value - i.StartTime).TotalHours)
            .ToList();
        var avgHours = completedDurations.Count == 0 ? 0m : completedDurations.Average();

        int timeoutCount = 0;
        int processedTaskCount = 0;
        if (instances.Count > 0)
        {
            var instanceIds = instances.Select(i => i.Id).ToList();
            timeoutCount = await _logRep.AsQueryable()
                .Where(l => instanceIds.Contains(l.InstanceId) && l.Action == FlowLogActionEnum.AutoTimeout)
                .CountAsync();
            processedTaskCount = await _taskRep.AsQueryable()
                .Where(t => instanceIds.Contains(t.InstanceId)
                    && t.Status != FlowTaskStatusEnum.Pending
                    && t.Status != FlowTaskStatusEnum.Cancelled)
                .CountAsync();
        }

        var dailyStart = new Dictionary<string, int>();
        foreach (var i in instances)
            AddCount(dailyStart, i.StartTime.Date.ToString("yyyy-MM-dd"));
        var dailyComp = new Dictionary<string, int>();
        foreach (var i in instances.Where(x => x.EndTime.HasValue && x.Status == FlowInstanceStatusEnum.Approved))
            AddCount(dailyComp, i.EndTime!.Value.Date.ToString("yyyy-MM-dd"));

        var trend = new List<FlowTrendItem>();
        for (var d = start.Date; d <= end.Date; d = d.AddDays(1))
        {
            var key = d.ToString("yyyy-MM-dd");
            trend.Add(new FlowTrendItem
            {
                Date = key,
                StartedCount = dailyStart.GetValueOrDefault(key),
                CompletedCount = dailyComp.GetValueOrDefault(key),
            });
        }

        return new FlowOverviewOutput
        {
            TotalInstances = total,
            CompletedInstances = completed,
            CompletionRate = total == 0 ? 0m : Math.Round((decimal)completed / total, 4),
            AvgDurationHours = Math.Round(avgHours, 2),
            TimeoutTaskCount = timeoutCount,
            TimeoutRate = processedTaskCount == 0 ? 0m : Math.Round((decimal)timeoutCount / processedTaskCount, 4),
            DailyTrend = trend,
        };
    }

    /// <summary>
    /// 表①：按流程维度统计
    /// </summary>
    [HttpPost]
    [ApiDescriptionSettings(Name = "ByFlow")]
    [DisplayName("按流程统计")]
    public async Task<List<FlowByFlowOutput>> ByFlow(FlowStatisticsInput input)
    {
        var rows = await BuildInstanceQuery(input)
            .Select(i => new { i.FlowId, i.Status, i.StartTime, i.EndTime, i.BizType })
            .ToListAsync();
        if (rows.Count == 0) return new();

        var flowIds = rows.Select(r => r.FlowId).Distinct().ToList();
        var flows = await _flowRep.AsQueryable()
            .Where(f => flowIds.Contains(f.Id))
            .Select(f => new { f.Id, f.Code, f.Name, f.BizType })
            .ToListAsync();
        var flowMap = flows.ToDictionary(f => f.Id);

        var bizTypeCodes = rows.Select(r => r.BizType)
            .Where(s => !string.IsNullOrEmpty(s))
            .Distinct()
            .ToList();
        var bizTypeMap = new Dictionary<string, string>();
        if (bizTypeCodes.Count > 0)
        {
            var bizTypes = await _bizTypeRep.AsQueryable()
                .Where(b => bizTypeCodes.Contains(b.Code))
                .Select(b => new { b.Code, b.Name })
                .ToListAsync();
            bizTypeMap = bizTypes.ToDictionary(b => b.Code, b => b.Name);
        }

        return rows.GroupBy(r => r.FlowId).Select(g =>
        {
            var durations = g.Where(x => x.Status == FlowInstanceStatusEnum.Approved && x.EndTime.HasValue)
                .Select(x => (decimal)(x.EndTime!.Value - x.StartTime).TotalHours)
                .ToList();
            var completedCount = g.Count(x => x.Status == FlowInstanceStatusEnum.Approved);
            var rejectedCount = g.Count(x => x.Status == FlowInstanceStatusEnum.Rejected);
            flowMap.TryGetValue(g.Key, out var flow);
            var bizType = flow?.BizType ?? g.First().BizType;

            return new FlowByFlowOutput
            {
                FlowId = g.Key,
                FlowCode = flow?.Code,
                FlowName = flow?.Name ?? "(已删除)",
                BizType = bizType,
                BizTypeName = !string.IsNullOrEmpty(bizType) && bizTypeMap.TryGetValue(bizType!, out var bn) ? bn : null,
                TotalCount = g.Count(),
                CompletedCount = completedCount,
                RunningCount = g.Count(x => x.Status == FlowInstanceStatusEnum.Running),
                RejectedCount = rejectedCount,
                PassRate = (completedCount + rejectedCount) == 0
                    ? 0m
                    : Math.Round((decimal)completedCount / (completedCount + rejectedCount), 4),
                AvgDurationHours = durations.Count == 0 ? 0m : Math.Round(durations.Average(), 2),
                MaxDurationHours = durations.Count == 0 ? 0m : Math.Round(durations.Max(), 2),
            };
        })
        .OrderByDescending(x => x.TotalCount)
        .ToList();
    }

    /// <summary>
    /// 表②：按节点维度统计（核心瓶颈分析）
    /// </summary>
    [HttpPost]
    [ApiDescriptionSettings(Name = "ByNode")]
    [DisplayName("按节点统计")]
    public async Task<List<FlowByNodeOutput>> ByNode(FlowStatisticsInput input)
    {
        var instances = await BuildInstanceQuery(input)
            .Select(i => new { i.Id, i.FlowId })
            .ToListAsync();
        if (instances.Count == 0) return new();
        var instanceIds = instances.Select(i => i.Id).ToList();
        var idToFlow = instances.ToDictionary(i => i.Id, i => i.FlowId);

        var completedNodes = await _completedNodeRep.AsQueryable()
            .Where(c => instanceIds.Contains(c.InstanceId))
            .Select(c => new { c.InstanceId, c.NodeId, c.NodeName, c.NodeType, c.CompletedTime })
            .ToListAsync();
        if (completedNodes.Count == 0) return new();

        var tasks = await _taskRep.AsQueryable()
            .Where(t => instanceIds.Contains(t.InstanceId))
            .Select(t => new { t.InstanceId, t.NodeId, t.Status, t.AssigneeId, t.AssigneeName, t.CreateTime, t.ActionTime })
            .ToListAsync();

        var autoTimeoutLogs = await _logRep.AsQueryable()
            .Where(l => instanceIds.Contains(l.InstanceId) && l.Action == FlowLogActionEnum.AutoTimeout)
            .Select(l => new { l.InstanceId, l.NodeId })
            .ToListAsync();
        var timeoutCountByNode = autoTimeoutLogs
            .Where(l => !string.IsNullOrEmpty(l.NodeId))
            .GroupBy(l => (idToFlow[l.InstanceId], l.NodeId!))
            .ToDictionary(g => g.Key, g => g.Count());

        var flowIds = instances.Select(i => i.FlowId).Distinct().ToList();
        var flows = await _flowRep.AsQueryable()
            .Where(f => flowIds.Contains(f.Id))
            .Select(f => new { f.Id, f.Code, f.Name })
            .ToListAsync();
        var flowDict = flows.ToDictionary(f => f.Id);

        var result = new List<FlowByNodeOutput>();
        foreach (var grp in completedNodes.GroupBy(c => (FlowId: idToFlow[c.InstanceId], c.NodeId)))
        {
            var flowId = grp.Key.FlowId;
            var nodeId = grp.Key.NodeId;
            var sample = grp.First();

            var nodeTasks = tasks
                .Where(t => t.NodeId == nodeId && idToFlow[t.InstanceId] == flowId
                    && (t.Status == FlowTaskStatusEnum.Approved
                        || t.Status == FlowTaskStatusEnum.Rejected
                        || t.Status == FlowTaskStatusEnum.Transferred))
                .ToList();

            decimal avgHours = 0, maxHours = 0;
            string? longest = null, shortest = null;
            var withAction = nodeTasks.Where(t => t.ActionTime.HasValue).ToList();
            if (withAction.Count > 0)
            {
                var durations = withAction
                    .Select(t => (decimal)(t.ActionTime!.Value - t.CreateTime).TotalHours)
                    .ToList();
                avgHours = Math.Round(durations.Average(), 2);
                maxHours = Math.Round(durations.Max(), 2);

                var longestTask = withAction
                    .OrderByDescending(t => (t.ActionTime!.Value - t.CreateTime).TotalHours)
                    .First();
                var shortestTask = withAction
                    .OrderBy(t => (t.ActionTime!.Value - t.CreateTime).TotalHours)
                    .First();
                longest = longestTask.AssigneeName;
                shortest = shortestTask.AssigneeName;
            }

            var approveCount = nodeTasks.Count(t => t.Status == FlowTaskStatusEnum.Approved);
            var rejectCount = nodeTasks.Count(t => t.Status == FlowTaskStatusEnum.Rejected);
            timeoutCountByNode.TryGetValue((flowId, nodeId), out var timeoutCount);

            var pending = tasks.Count(t => t.NodeId == nodeId && idToFlow[t.InstanceId] == flowId
                && t.Status == FlowTaskStatusEnum.Pending);

            flowDict.TryGetValue(flowId, out var flow);
            result.Add(new FlowByNodeOutput
            {
                FlowId = flowId,
                FlowCode = flow?.Code,
                FlowName = flow?.Name ?? "(已删除)",
                NodeId = nodeId,
                NodeName = sample.NodeName,
                NodeType = sample.NodeType,
                FlowCount = grp.Count(),
                AvgDurationHours = avgHours,
                MaxDurationHours = maxHours,
                ApproveCount = approveCount,
                RejectCount = rejectCount,
                RejectRate = (approveCount + rejectCount) == 0
                    ? 0m
                    : Math.Round((decimal)rejectCount / (approveCount + rejectCount), 4),
                TimeoutCount = timeoutCount,
                PendingCount = pending,
                LongestApproverName = longest,
                ShortestApproverName = shortest,
            });
        }

        return result.OrderByDescending(x => x.AvgDurationHours).ToList();
    }

    /// <summary>
    /// 表③：按审批人维度统计
    /// </summary>
    [HttpPost]
    [ApiDescriptionSettings(Name = "ByApprover")]
    [DisplayName("按审批人统计")]
    public async Task<List<FlowByApproverOutput>> ByApprover(FlowStatisticsInput input)
    {
        var instanceIds = await BuildInstanceQuery(input).Select(i => i.Id).ToListAsync();
        if (instanceIds.Count == 0) return new();

        var tasks = await _taskRep.AsQueryable()
            .Where(t => instanceIds.Contains(t.InstanceId) && t.AssigneeId > 0)
            .Select(t => new { t.InstanceId, t.NodeId, t.Status, t.AssigneeId, t.AssigneeName, t.CreateTime, t.ActionTime })
            .ToListAsync();
        if (tasks.Count == 0) return new();

        var approverIds = tasks.Select(t => t.AssigneeId).Distinct().ToList();
        var orgRows = await _instanceRep.Context.Queryable<SysUser>()
            .LeftJoin<SysOrg>((u, o) => u.OrgId == o.Id)
            .Where(u => approverIds.Contains(u.Id))
            .Select((u, o) => new { UserId = u.Id, OrgName = o.Name })
            .ToListAsync();
        var orgDict = orgRows.ToDictionary(x => x.UserId, x => x.OrgName);

        var timeoutLogs = await _logRep.AsQueryable()
            .Where(l => instanceIds.Contains(l.InstanceId) && l.Action == FlowLogActionEnum.AutoTimeout)
            .Select(l => new { l.InstanceId, l.NodeId })
            .ToListAsync();
        var timeoutKey = timeoutLogs
            .Where(l => !string.IsNullOrEmpty(l.NodeId))
            .Select(l => (l.InstanceId, l.NodeId))
            .ToHashSet();

        return tasks.GroupBy(t => t.AssigneeId).Select(g =>
        {
            var completed = g.Where(t => t.Status == FlowTaskStatusEnum.Approved
                                        || t.Status == FlowTaskStatusEnum.Rejected
                                        || t.Status == FlowTaskStatusEnum.Transferred)
                .ToList();
            var durations = completed.Where(t => t.ActionTime.HasValue)
                .Select(t => (decimal)(t.ActionTime!.Value - t.CreateTime).TotalHours)
                .ToList();
            var timeoutCount = g.Count(t => timeoutKey.Contains((t.InstanceId, t.NodeId)));

            return new FlowByApproverOutput
            {
                ApproverId = g.Key,
                ApproverName = g.First().AssigneeName ?? "",
                OrgName = orgDict.GetValueOrDefault(g.Key),
                TotalAssigned = g.Count(),
                CompletedCount = completed.Count,
                PendingCount = g.Count(t => t.Status == FlowTaskStatusEnum.Pending),
                AvgProcessHours = durations.Count == 0 ? 0m : Math.Round(durations.Average(), 2),
                TimeoutCount = timeoutCount,
                ApproveCount = g.Count(t => t.Status == FlowTaskStatusEnum.Approved),
                RejectCount = g.Count(t => t.Status == FlowTaskStatusEnum.Rejected),
                TransferCount = g.Count(t => t.Status == FlowTaskStatusEnum.Transferred),
            };
        })
        .OrderByDescending(x => x.TotalAssigned)
        .ToList();
    }

    /// <summary>
    /// Top 10 最慢节点（柱图数据，仅包含 userTask）
    /// </summary>
    [HttpPost]
    [ApiDescriptionSettings(Name = "TopSlowNodes")]
    [DisplayName("最慢节点Top10")]
    public async Task<List<FlowTopSlowNodeItem>> TopSlowNodes(FlowStatisticsInput input)
    {
        var nodes = await ByNode(input);
        return nodes
            .Where(n => n.AvgDurationHours > 0
                && (n.NodeType == null || n.NodeType == "bpmn:userTask"))
            .OrderByDescending(n => n.AvgDurationHours)
            .Take(10)
            .Select(n => new FlowTopSlowNodeItem
            {
                FlowName = n.FlowName,
                NodeName = n.NodeName ?? n.NodeId,
                AvgDurationHours = n.AvgDurationHours,
                FlowCount = n.FlowCount,
            })
            .ToList();
    }

    // ───────────────── helpers ─────────────────

    private (DateTime start, DateTime end) NormalizeRange(FlowStatisticsInput input)
    {
        var end = input.EndTime ?? DateTime.Now;
        var start = input.StartTime ?? end.AddDays(-30);
        if (start > end) (start, end) = (end, start);
        return (start, end);
    }

    private ISugarQueryable<ApprovalFlowInstance> BuildInstanceQuery(FlowStatisticsInput input)
    {
        var (start, end) = NormalizeRange(input);
        var q = _instanceRep.AsQueryable()
            .Where(i => i.StartTime >= start && i.StartTime <= end);
        if (input.FlowIds != null && input.FlowIds.Count > 0)
            q = q.Where(i => input.FlowIds.Contains(i.FlowId));
        if (input.BizTypes != null && input.BizTypes.Count > 0)
            q = q.Where(i => input.BizTypes.Contains(i.BizType));
        if (input.InitiatorOrgIds != null && input.InitiatorOrgIds.Count > 0)
            q = q.Where(i => input.InitiatorOrgIds.Contains(i.OrgId));
        return q;
    }

    private static void AddCount(Dictionary<string, int> dict, string key)
    {
        dict[key] = dict.GetValueOrDefault(key) + 1;
    }

    private class InstanceLite
    {
        public long Id { get; set; }
        public FlowInstanceStatusEnum Status { get; set; }
        public DateTime StartTime { get; set; }
        public DateTime? EndTime { get; set; }
    }
}