/*
 Copyright 2019 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
 http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

import Foundation

extension EmojiItem: Decodable {
    
    enum CodingKeys: String, CodingKey {
        case code = "b"
        case name = "a"
        case shortNames = "n"
        case keywords = "j"
    }
    
    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        
        guard let identifier = decoder.codingPath.last?.stringValue else {
            throw DecodingError.dataCorruptedError(forKey: .code, in: container, debugDescription: "Cannot initialize identifier")
        }
        
        let emojiUnicodeStringValue = try container.decode(String.self, forKey: .code)
        
        let unicodeStringComponents = emojiUnicodeStringValue.components(separatedBy: "-")
        
        var emoji = ""
        
        for unicodeStringComponent in unicodeStringComponents {
            if let unicodeCodePoint = Int(unicodeStringComponent, radix: 16),
                let emojiUnicodeScalar = UnicodeScalar(unicodeCodePoint) {
                emoji.append(String(emojiUnicodeScalar))
            } else {
                throw DecodingError.dataCorruptedError(forKey: .code, in: container, debugDescription: "Cannot initialize emoji")
            }
        }
        
        let name = try container.decode(String.self, forKey: .name)
        
        let shortNames: [String]
        
        if let decodedShortNames = try container.decodeIfPresent([String].self, forKey: .shortNames) {
            shortNames = decodedShortNames
        } else {
            shortNames = []
        }
        
        let keywords: [String]
        
        if let decodedKeywords = try container.decodeIfPresent([String].self, forKey: .keywords) {
            keywords = decodedKeywords
        } else {
            keywords = []
        }
        
        self.init(identifier: identifier,
                  value: emoji,
                  name: name,
                  shortNames: shortNames,
                  keywords: keywords)
    }
}