using System.Text.RegularExpressions;
using AMREZ.EOP.Abstractions.Applications.Tenancy;
using AMREZ.EOP.Contracts.DTOs.Authentications.Login;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;

namespace AMREZ.EOP.Infrastructures.Tenancy;

public sealed class DefaultTenantResolver : ITenantResolver
{
    private readonly TenantMap _map;
    private readonly ILogger<DefaultTenantResolver>? _log;

    // แพลตฟอร์มสลัก (ปรับตามระบบจริงได้) — ใช้ "public" เป็นค่าเริ่ม
    private const string PlatformSlug = "public";

    public DefaultTenantResolver(
        TenantMap map,
        ILogger<DefaultTenantResolver>? log = null
    )
    {
        _map = map;
        _log = log;
    }

    public ITenantContext? Resolve(HttpContext http, object? hint = null)
    {
        var cid = http.TraceIdentifier;
        var path = http.Request.Path.Value ?? string.Empty;

        if (hint is string hs && string.Equals(hs, "@platform", StringComparison.OrdinalIgnoreCase))
        {
            if (_map.TryGetBySlug(PlatformSlug, out var platform))
            {
                _log?.LogInformation("Resolved by hint=@platform -> {Slug} cid={Cid}", PlatformSlug, cid);
                return platform;
            }
            _log?.LogWarning("Platform slug '{Slug}' not found in TenantMap cid={Cid}", PlatformSlug, cid);
            return null;
        }

        if (path.StartsWith("/api/Tenancy", StringComparison.OrdinalIgnoreCase))
        {
            if (_map.TryGetBySlug(PlatformSlug, out var platform))
            {
                // เก็บ target tenant แยกไว้ให้ repo/usecase ใช้
                var headerTenant = http.Request.Headers["X-Tenant"].ToString();
                if (!string.IsNullOrWhiteSpace(headerTenant))
                    http.Items["TargetTenantKey"] = headerTenant.Trim().ToLowerInvariant();

                _log?.LogInformation("Resolved CONTROL-PLANE -> platform:{Slug} (path={Path}) cid={Cid}", PlatformSlug, path, cid);
                return platform;
            }
            _log?.LogWarning("CONTROL-PLANE path but platform slug '{Slug}' missing cid={Cid}", PlatformSlug, cid);
            return null;
        }

        var header = http.Request.Headers["X-Tenant"].ToString();
        if (!string.IsNullOrWhiteSpace(header) && _map.TryGetBySlug(header, out var byHeader))
        {
            _log?.LogInformation("Resolved by header: {Tenant} cid={Cid}", header, cid);
            return byHeader;
        }

        var host = http.Request.Host.Host;
        if (_map.TryGetByDomain(host, out var byDomain))
        {
            _log?.LogInformation("Resolved by domain: {Host} -> {TenantId} cid={Cid}", host, byDomain.Id, cid);
            return byDomain;
        }

        var sub = GetSubdomain(host);
        if (sub != null && _map.TryGetBySlug(sub, out var bySub))
        {
            _log?.LogInformation("Resolved by subdomain: {Sub} cid={Cid}", sub, cid);
            return bySub;
        }

        if (hint is LoginRequest body && !string.IsNullOrWhiteSpace(body.Tenant) &&
            _map.TryGetBySlug(body.Tenant!, out var byBody))
        {
            _log?.LogInformation("Resolved by body: {Tenant} cid={Cid}", body.Tenant, cid);
            return byBody;
        }

        _log?.LogWarning("Resolve FAILED host={Host} header={Header} cid={Cid}",
            host, string.IsNullOrWhiteSpace(header) ? "<empty>" : header, cid);
        return null;
    }

    private static string? GetSubdomain(string host)
    {
        if (Regex.IsMatch(host, @"^\d{1,3}(\.\d{1,3}){3}$")) return null; // IP
        var parts = host.Split('.', StringSplitOptions.RemoveEmptyEntries);
        return parts.Length >= 3 ? parts[0] : null;
    }
}