Add support for Emergency Access (#1000)

* Add support for Emergency Access

* Add migration script

* Review comments

* Ensure grantor has premium when inviting new grantees.

* Resolve review comments

* Remove two factor references

src/Core/Models/Api/Request/EmergencyAccessRequstModels.cs

@@ -0,0 +1,47 @@
+using System.ComponentModel.DataAnnotations;
+using Bit.Core.Models.Table;
+
+namespace Bit.Core.Models.Api.Request
+{
+    public class EmergencyAccessInviteRequestModel
+    {
+        [Required]
+        [EmailAddress]
+        [StringLength(50)]
+        public string Email { get; set; }
+        [Required]
+        public Enums.EmergencyAccessType? Type { get; set; }
+        [Required]
+        public int WaitTimeDays { get; set; }
+    }
+
+    public class EmergencyAccessUpdateRequestModel
+    {
+        [Required]
+        public Enums.EmergencyAccessType Type { get; set; }
+        [Required]
+        public int WaitTimeDays { get; set; }
+        public string KeyEncrypted { get; set; }
+
+        public EmergencyAccess ToEmergencyAccess(EmergencyAccess existingEmergencyAccess)
+        {
+            // Ensure we only set keys for a confirmed emergency access.
+            if (!string.IsNullOrWhiteSpace(existingEmergencyAccess.KeyEncrypted) && !string.IsNullOrWhiteSpace(KeyEncrypted))
+            {
+                existingEmergencyAccess.KeyEncrypted = KeyEncrypted;
+            }
+            existingEmergencyAccess.Type = Type;
+            existingEmergencyAccess.WaitTimeDays = WaitTimeDays;
+            return existingEmergencyAccess;
+        }
+    }
+
+    public class EmergencyAccessPasswordRequestModel
+    {
+        [Required]
+        [StringLength(300)]
+        public string NewMasterPasswordHash { get; set; }
+        [Required]
+        public string Key { get; set; }
+    }
+}

src/Core/Models/Api/Response/EmergencyAccessResponseModel.cs

@@ -0,0 +1,119 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Bit.Core.Enums;
+using Bit.Core.Models.Data;
+using Bit.Core.Models.Table;
+using Core.Models.Data;
+
+namespace Bit.Core.Models.Api.Response
+{
+    public class EmergencyAccessResponseModel : ResponseModel
+    {
+        public EmergencyAccessResponseModel(EmergencyAccess emergencyAccess, string obj = "emergencyAccess") : base(obj)
+        {
+            if (emergencyAccess == null)
+            {
+                throw new ArgumentNullException(nameof(emergencyAccess));
+            }
+
+            Id = emergencyAccess.Id.ToString();
+            Status = emergencyAccess.Status;
+            Type = emergencyAccess.Type;
+            WaitTimeDays = emergencyAccess.WaitTimeDays;
+        }
+
+        public EmergencyAccessResponseModel(EmergencyAccessDetails emergencyAccess, string obj = "emergencyAccess") : base(obj)
+        {
+            if (emergencyAccess == null)
+            {
+                throw new ArgumentNullException(nameof(emergencyAccess));
+            }
+
+            Id = emergencyAccess.Id.ToString();
+            Status = emergencyAccess.Status;
+            Type = emergencyAccess.Type;
+            WaitTimeDays = emergencyAccess.WaitTimeDays;
+        }
+
+        public string Id { get; private set; }
+        public EmergencyAccessStatusType Status { get; private set; }
+        public EmergencyAccessType Type { get; private set; }
+        public int WaitTimeDays { get; private set; }
+    }
+
+    public class EmergencyAccessGranteeDetailsResponseModel : EmergencyAccessResponseModel
+    {
+        public EmergencyAccessGranteeDetailsResponseModel(EmergencyAccessDetails emergencyAccess)
+            : base(emergencyAccess, "emergencyAccessGranteeDetails")
+        {
+            if (emergencyAccess == null)
+            {
+                throw new ArgumentNullException(nameof(emergencyAccess));
+            }
+
+            GranteeId = emergencyAccess.GranteeId.ToString();
+            Email = emergencyAccess.GranteeEmail;
+            Name = emergencyAccess.GranteeName;
+        }
+
+        public string GranteeId { get; private set; }
+        public string Name { get; private set; }
+        public string Email { get; private set; }
+    }
+
+    public class EmergencyAccessGrantorDetailsResponseModel : EmergencyAccessResponseModel
+    {
+        public EmergencyAccessGrantorDetailsResponseModel(EmergencyAccessDetails emergencyAccess)
+            : base(emergencyAccess, "emergencyAccessGrantorDetails")
+        {
+            if (emergencyAccess == null)
+            {
+                throw new ArgumentNullException(nameof(emergencyAccess));
+            }
+
+            GrantorId = emergencyAccess.GrantorId.ToString();
+            Email = emergencyAccess.GrantorEmail;
+            Name = emergencyAccess.GrantorName;
+        }
+
+        public string GrantorId { get; private set; }
+        public string Name { get; private set; }
+        public string Email { get; private set; }
+    }
+
+    public class EmergencyAccessTakeoverResponseModel : ResponseModel
+    {
+        public EmergencyAccessTakeoverResponseModel(EmergencyAccess emergencyAccess, User grantor, string obj = "emergencyAccessTakeover") : base(obj)
+        {
+            if (emergencyAccess == null)
+            {
+                throw new ArgumentNullException(nameof(emergencyAccess));
+            }
+
+            KeyEncrypted = emergencyAccess.KeyEncrypted;
+            Kdf = grantor.Kdf;
+            KdfIterations = grantor.KdfIterations;
+        }
+
+        public int KdfIterations { get; private set; }
+        public KdfType Kdf { get; private set; }
+        public string KeyEncrypted { get; private set; }
+    }
+
+    public class EmergencyAccessViewResponseModel : ResponseModel
+    {
+        public EmergencyAccessViewResponseModel(
+            GlobalSettings globalSettings,
+            EmergencyAccess emergencyAccess,
+            IEnumerable<CipherDetails> ciphers)
+            : base("emergencyAccessView")
+        {
+            KeyEncrypted = emergencyAccess.KeyEncrypted;
+            Ciphers = ciphers.Select(c => new CipherResponseModel(c, globalSettings));
+        }
+        
+        public string KeyEncrypted { get; set; }
+        public IEnumerable<CipherResponseModel> Ciphers { get; set; }
+    }
+}