48 lines
1.7 KiB
Swift
48 lines
1.7 KiB
Swift
//
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// Copyright 2022 New Vector Ltd
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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import Foundation
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/// Simple view model that computes the placeholder avatar properties.
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struct PlaceholderAvatarViewModel {
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/// The displayname used to create the `firstCharacterCapitalized`.
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let displayName: String?
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/// The matrix id used as input to create the `stableColorIndex` from.
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let matrixItemId: String
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/// The number of total colors available for the `stableColorIndex`.
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let colorCount: Int
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/// Get the first character of the display name capitalized or else a space character.
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var firstCharacterCapitalized: Character {
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displayName?.capitalized.first ?? " "
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}
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/// Provides the same color each time for a specified matrixId
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///
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/// Same algorithm as in AvatarGenerator.
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/// - Parameters:
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/// - matrixItemId: the matrix id used as input to create the stable index.
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/// - Returns: The stable index.
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var stableColorIndex: Int {
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// Sum all characters
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let sum = matrixItemId.utf8
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.map { UInt($0) }
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.reduce(0, +)
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// modulo the color count
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return Int(sum) % colorCount
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}
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}
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