using System.Collections.Concurrent;
using Admin.NET.Plugin.AiDOP.MaterialWarehouse.InventoryPosting.Entity;

namespace Admin.NET.Plugin.AiDOP.MaterialWarehouse.InventoryPosting.Idempotency;

/// <summary>
/// 线程安全内存幂等存储——用于并发/单元测试。以 ConcurrentDictionary.TryAdd 模拟
/// (tenant_id, domain_code, fbillno) 的 DB UNIQUE 原子占位语义（TryAdd 原子，多并发仅一路成功）。
/// **不代表真实 MySQL 唯一约束**（那属 Phase 4B）。
/// </summary>
public sealed class InMemoryIqcPostingStore : IIqcPostingStore
{
    private readonly ConcurrentDictionary<string, AdoIqcInventoryPosting> _store =
        new(StringComparer.Ordinal);

    private static string Key(long tenantId, string domainCode, string fbillNo)
        => $"{tenantId}|{domainCode ?? string.Empty}|{fbillNo ?? string.Empty}";

    public Task<PostingInsertResult> TryInsertAsync(AdoIqcInventoryPosting posting)
    {
        if (posting == null) throw new ArgumentNullException(nameof(posting));
        var key = Key(posting.TenantId, posting.DomainCode, posting.FbillNo);
        var inserted = _store.TryAdd(key, posting);
        return Task.FromResult(new PostingInsertResult
        {
            Inserted = inserted,
            Existing = inserted ? null : _store.TryGetValue(key, out var e) ? e : null,
        });
    }

    public Task<AdoIqcInventoryPosting> GetAsync(long tenantId, string domainCode, string fbillNo)
    {
        _store.TryGetValue(Key(tenantId, domainCode, fbillNo), out var e);
        return Task.FromResult(e);
    }

    public Task UpdateStatusAsync(AdoIqcInventoryPosting posting, string status)
    {
        if (posting == null) throw new ArgumentNullException(nameof(posting));
        if (_store.TryGetValue(Key(posting.TenantId, posting.DomainCode, posting.FbillNo), out var e))
        {
            lock (e) { e.PostingStatus = status; e.UpdateTime = DateTime.Now; }
        }
        posting.PostingStatus = status;
        return Task.CompletedTask;
    }

    /// <summary>原子抢占：对既有记录取锁，校验 PROCESSING + stale 后刷新心跳。lock(e) 保证并发仅一路成功。</summary>
    public Task<bool> TryRecoverStaleAsync(long tenantId, string domainCode, string fbillNo, DateTime staleBefore, DateTime now)
    {
        if (!_store.TryGetValue(Key(tenantId, domainCode, fbillNo), out var e))
            return Task.FromResult(false);
        lock (e)
        {
            var status = (e.PostingStatus ?? string.Empty).Trim().ToUpperInvariant();
            var heartbeat = e.UpdateTime ?? e.CreateTime;
            if (status == "PROCESSING" && heartbeat < staleBefore)
            {
                e.UpdateTime = now;   // 续租=抢占
                return Task.FromResult(true);
            }
            return Task.FromResult(false);
        }
    }
}