session-ios/SessionMessagingKit/Database/Models/Capability.swift

// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.

import Foundation
import GRDB
import SessionUtilitiesKit

public struct Capability: Codable, FetchableRecord, PersistableRecord, TableRecord, ColumnExpressible {
    public static var databaseTableName: String { "capability" }
    
    public typealias Columns = CodingKeys
    public enum CodingKeys: String, CodingKey, ColumnExpression {
        case openGroupServer
        case variant
        case isMissing
    }
    
    public enum Variant: Equatable, Hashable, CaseIterable, Codable, DatabaseValueConvertible {
        public static var allCases: [Variant] {
            [.sogs, .blind]
        }
        
        case sogs
        case blind
        
        /// Fallback case if the capability isn't supported by this version of the app
        case unsupported(String)
        
        // MARK: - Convenience
        
        public var rawValue: String {
            switch self {
                case .unsupported(let originalValue): return originalValue
                default: return "\(self)"
            }
        }
        
        // MARK: - Initialization
        
        public init(from valueString: String) {
            let maybeValue: Variant? = Variant.allCases.first { $0.rawValue == valueString }
            
            self = (maybeValue ?? .unsupported(valueString))
        }
    }
    
    public let openGroupServer: String
    public let variant: Variant
    public let isMissing: Bool
    
    // MARK: - Initialization
    
    public init(
        openGroupServer: String,
        variant: Variant,
        isMissing: Bool
    ) {
        self.openGroupServer = openGroupServer
        self.variant = variant
        self.isMissing = isMissing
    }
}

extension Capability.Variant {
    // MARK: - Codable

    public init(from decoder: Decoder) throws {
        let container: SingleValueDecodingContainer = try decoder.singleValueContainer()
        let valueString: String = try container.decode(String.self)
        
        // FIXME: Remove this code
        // There was a point where we didn't have custom Codable handling for the Capability.Variant
        // which resulted in the data being encoded into the database as a JSON dict - this code catches
        // that case and extracts the standard string value so it can be processed the same as the
        // "proper" custom Codable logic)
        if valueString.starts(with: "{") {
            self = Capability.Variant(
                from: valueString
                    .replacingOccurrences(of: "\":{}}", with: "")
                    .replacingOccurrences(of: "\"}}", with: "")
                    .replacingOccurrences(of: "{\"unsupported\":{\"_0\":\"", with: "")
                    .replacingOccurrences(of: "{\"", with: "")
            )
            return
        }
        // FIXME: Remove this code ^^^
        
        self = Capability.Variant(from: valueString)
    }

    public func encode(to encoder: Encoder) throws {
        var container: SingleValueEncodingContainer = encoder.singleValueContainer()

        try container.encode(rawValue)
    }
}