using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

using Abp.Collections.Extensions;
using Abp.Domain.Entities;
using Abp.Domain.Entities.Auditing;
using Abp.Extensions;

namespace VberZero.BaseSystem.Organizations;

/// <summary>
/// 组织单位 (OU)。
/// </summary>
[Table("Sys_OrganizationUnits")]
public class OrganizationUnit : FullAuditedEntity<long>, IMayHaveTenant
{
    public const int MaxDisplayNameLength = 128;

    public const int MaxDepth = 16;

    public const int CodeUnitLength = 5;

    public const int MaxCodeLength = MaxDepth * (CodeUnitLength + 1) - 1;
    public const int MaxPathLength = 1000;

    public virtual int? TenantId { get; set; }

    /// <summary>
    /// 父 <see cref="OrganizationUnit"/>
    /// 空，如果这个 OU 是根
    /// </summary>
    [ForeignKey("ParentId")]
    public virtual OrganizationUnit Parent { get; set; }

    /// <summary>
    /// 父 <see cref="OrganizationUnit"/> Id
    /// 空，如果这个 OU 是根
    /// </summary>
    public virtual long? ParentId { get; set; }

    /// <summary>
    /// 本组织单位的层级代码
    /// </summary>
    [Required]
    [StringLength(MaxCodeLength)]
    public virtual string? Code { get; set; }

    public virtual string Path { get; set; }
    public virtual bool IsLeaf { get; set; }

    /// <summary>
    /// 显示名称
    /// </summary>
    [Required]
    [StringLength(MaxDisplayNameLength)]
    public virtual string DisplayName { get; set; }

    public virtual ICollection<OrganizationUnit> Children { get; set; }

    public OrganizationUnit()
    {
    }

    public OrganizationUnit(int? tenantId, string displayName, long? parentId = null)
    {
        TenantId = tenantId;
        DisplayName = displayName;
        ParentId = parentId;
    }

    /// <summary>
    /// 为给定数字创建代码。
    /// 示例：如果数字是 4,2，则返回“00004.00002”；
    /// </summary>
    /// <param name="numbers">Numbers</param>
    public static string? CreateCode(params int[] numbers)
    {
        if (numbers.IsNullOrEmpty())
        {
            return null;
        }

        return numbers.Select(number => number.ToString(new string('0', CodeUnitLength))).JoinAsString(".");
    }

    /// <summary>
    /// 将子代码附加到父代码。
    /// 示例：如果 parentCode = "00001", childCode = "00042" 然后返回 "00001.00042"。
    /// </summary>
    /// <param name="parentCode">Parent code. Can be null or empty if parent is a root.</param>
    /// <param name="childCode">Child code.</param>
    public static string? AppendCode(string? parentCode, string? childCode)
    {
        if (childCode.IsNullOrEmpty())
        {
            throw new ArgumentNullException(nameof(childCode), "childCode can not be null or empty.");
        }

        if (parentCode.IsNullOrEmpty())
        {
            return childCode;
        }

        return parentCode + "." + childCode;
    }

    /// <summary>
    /// 获取父级的相关代码。
    /// 示例：如果代码 = "00019.00055.00001" 且 parentCode = "00019"，则返回 "00055.00001"。
    /// </summary>
    /// <param name="code">The code.</param>
    /// <param name="parentCode">The parent code.</param>
    public static string? GetRelativeCode(string? code, string? parentCode)
    {
        if (code.IsNullOrEmpty())
        {
            throw new ArgumentNullException(nameof(code), "code can not be null or empty.");
        }

        if (parentCode.IsNullOrEmpty())
        {
            return code;
        }

        if (code!.Length == parentCode!.Length)
        {
            return null;
        }

        return code.Substring(parentCode.Length + 1);
    }

    /// <summary>
    /// 计算给定代码的下一个代码。
    /// 示例：如果代码 = "00019.00055.00001" 返回 "00019.00055.00002"。
    /// </summary>
    /// <param name="code">The code.</param>
    public static string? CalculateNextCode(string? code)
    {
        if (code.IsNullOrEmpty())
        {
            throw new ArgumentNullException(nameof(code), "code can not be null or empty.");
        }

        var parentCode = GetParentCode(code);
        var lastUnitCode = GetLastUnitCode(code);

        return AppendCode(parentCode, CreateCode(Convert.ToInt32(lastUnitCode) + 1));
    }

    /// <summary>
    /// 获取最后一个单位代码。
    /// 示例：如果代码 = "00019.00055.00001" 返回 "00001"。
    /// </summary>
    /// <param name="code">The code.</param>
    public static string GetLastUnitCode(string? code)
    {
        if (code.IsNullOrEmpty())
        {
            throw new ArgumentNullException(nameof(code), "code can not be null or empty.");
        }

        var splittedCode = code!.Split('.');
        return splittedCode[^1];
    }

    /// <summary>
    /// 获取父代码。
    /// 示例：如果代码 = "00019.00055.00001" 返回 "00019.00055"。
    /// </summary>
    /// <param name="code">The code.</param>
    public static string? GetParentCode(string? code)
    {
        if (code.IsNullOrEmpty())
        {
            throw new ArgumentNullException(nameof(code), "code can not be null or empty.");
        }

        if (code == null)
        {
            return null;
        }
        var splittedCode = code.Split('.');
        if (splittedCode.Length == 1)
        {
            return null;
        }

        return splittedCode.Take(splittedCode.Length - 1).JoinAsString(".");
    }
}