namespace PS.IPAM.Cmdlets;

using System;
using System.Collections.Generic;
using System.Management.Automation;
using PS.IPAM.Helpers;

/// <summary>
/// Retrieves subnet information from phpIPAM.
/// </summary>
[Cmdlet(VerbsCommon.Get, "Subnet", DefaultParameterSetName = "NoParams")]
[OutputType(typeof(Subnetwork))]
public class GetSubnetCmdlet : BaseCmdlet
{
    [Parameter(
        Mandatory = true,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 0,
        ParameterSetName = "ByCIDR",
        HelpMessage = "The subnet in CIDR notation (e.g., 192.168.1.0/24).")]
    [ValidatePattern(@"^\d+\.\d+\.\d+\.\d+/\d{1,2}$")]
    [ValidateNotNullOrEmpty]
    public string? CIDR { get; set; }

    [Parameter(
        Mandatory = true,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 0,
        ParameterSetName = "ByID",
        HelpMessage = "The subnet ID.")]
    [ValidateNotNullOrEmpty]
    public int? Id { get; set; }

    [Parameter(
        Mandatory = true,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 0,
        ParameterSetName = "BySectionId",
        HelpMessage = "The section ID to get subnets from.")]
    [Parameter(
        Mandatory = false,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 2,
        ParameterSetName = "ByVlanNumber")]
    [Parameter(
        Mandatory = false,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 1,
        ParameterSetName = "ByVlanId")]
    [ValidateNotNullOrEmpty]
    public int? SectionId { get; set; }

    [Parameter(
        Mandatory = true,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 0,
        ParameterSetName = "BySectionName",
        HelpMessage = "The section name to get subnets from.")]
    [Parameter(
        Mandatory = false,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 3,
        ParameterSetName = "ByVlanNumber")]
    [Parameter(
        Mandatory = false,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 2,
        ParameterSetName = "ByVlanId")]
    [ValidateNotNullOrEmpty]
    public string? SectionName { get; set; }

    [Parameter(
        Mandatory = true,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 0,
        ParameterSetName = "ByVrfId",
        HelpMessage = "The VRF ID to get subnets from.")]
    [ValidateNotNullOrEmpty]
    public int? VrfId { get; set; }

    [Parameter(
        Mandatory = true,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 0,
        ParameterSetName = "ByVlanId",
        HelpMessage = "The VLAN ID to get subnets from.")]
    [ValidateNotNullOrEmpty]
    public int? VlanId { get; set; }

    [Parameter(
        Mandatory = true,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 0,
        ParameterSetName = "ByVlanNumber",
        HelpMessage = "The VLAN number to get subnets from.")]
    [ValidateNotNullOrEmpty]
    public int? VlanNumber { get; set; }

    [Parameter(
        Mandatory = false,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 1,
        ParameterSetName = "ByID",
        HelpMessage = "Get child subnets (slaves).")]
    public SwitchParameter Slaves { get; set; }

    [Parameter(
        Mandatory = false,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 2,
        ParameterSetName = "ByID",
        HelpMessage = "Get child subnets recursively.")]
    public SwitchParameter Recurse { get; set; }

    [Parameter(
        Mandatory = false,
        ValueFromPipeline = true,
        ValueFromPipelineByPropertyName = true,
        Position = 1,
        ParameterSetName = "ByVlanNumber",
        HelpMessage = "The L2 domain ID to narrow VLAN search.")]
    [ValidateNotNullOrEmpty]
    public int? VlanDomainId { get; set; }

    protected override void ProcessRecord()
    {
        try
        {
            var controller = ApiController.Subnets;
            var identifiers = new List<string>();

            switch (ParameterSetName)
            {
                case "ByCIDR":
                    identifiers.Add("cidr");
                    identifiers.Add(CIDR!);
                    break;

                case "ByID":
                    identifiers.Add(Id!.Value.ToString());
                    if (Slaves.IsPresent)
                    {
                        identifiers.Add(Recurse.IsPresent ? "slaves_recursive" : "slaves");
                    }
                    break;

                case "BySectionId":
                    controller = ApiController.Sections;
                    identifiers.Add(SectionId!.Value.ToString());
                    identifiers.Add("subnets");
                    break;

                case "BySectionName":
                    controller = ApiController.Sections;
                    var section = GetSectionByName(SectionName!);
                    identifiers.Add(section.Id.ToString());
                    identifiers.Add("subnets");
                    break;

                case "ByVrfId":
                    controller = ApiController.Vrf;
                    identifiers.Add(VrfId!.Value.ToString());
                    identifiers.Add("subnets");
                    break;

                case "ByVlanId":
                    controller = ApiController.Vlan;
                    identifiers.Add(VlanId!.Value.ToString());
                    identifiers.Add("subnets");
                    AddSectionIdentifier(identifiers);
                    break;

                case "ByVlanNumber":
                    controller = ApiController.Vlan;
                    var vlan = FindVlanByNumber(VlanNumber!.Value, VlanDomainId);
                    identifiers.Add(vlan.Id.ToString());
                    identifiers.Add("subnets");
                    AddSectionIdentifier(identifiers);
                    break;
            }

            var result = RequestHelper.InvokeRequest(
                "GET", controller, ModelType.Subnetwork, null, null, identifiers.ToArray()
            ).GetAwaiter().GetResult();

            WriteResult(result);
        }
        catch (Exception ex)
        {
            WriteError(new ErrorRecord(ex, "GetSubnetError", ErrorCategory.InvalidOperation, null));
        }
    }

    private Section GetSectionByName(string name)
    {
        var section = RequestHelper.InvokeRequest(
            "GET", ApiController.Sections, ModelType.Section, null, null, new[] { name }
        ).GetAwaiter().GetResult() as Section;

        if (section == null)
        {
            throw new ItemNotFoundException($"Section '{name}' not found.");
        }

        return section;
    }

    private Vlan FindVlanByNumber(int number, int? domainId)
    {
        var vlans = RequestHelper.InvokeRequest(
            "GET", ApiController.Vlan, ModelType.Vlan, null, null,
            new[] { "search", number.ToString() }
        ).GetAwaiter().GetResult();

        if (vlans == null)
        {
            throw new ItemNotFoundException($"VLAN {number} not found.");
        }

        Vlan? foundVlan = null;

        if (vlans is System.Collections.IEnumerable enumerable)
        {
            foreach (var v in enumerable)
            {
                if (v is Vlan vlan)
                {
                    if (domainId.HasValue && vlan.DomainId != domainId.Value)
                    {
                        continue;
                    }

                    if (foundVlan != null)
                    {
                        throw new InvalidOperationException(
                            $"Multiple VLANs with number {number} exist. Specify VlanDomainId to narrow the search.");
                    }

                    foundVlan = vlan;
                }
            }
        }

        if (foundVlan == null)
        {
            throw new ItemNotFoundException($"VLAN {number} not found.");
        }

        return foundVlan;
    }

    private void AddSectionIdentifier(List<string> identifiers)
    {
        if (SectionId.HasValue)
        {
            identifiers.Add(SectionId.Value.ToString());
        }
        else if (!string.IsNullOrEmpty(SectionName))
        {
            var section = GetSectionByName(SectionName);
            identifiers.Add(section.Id.ToString());
        }
    }
}