Add the basics of ViewStateController and withViewStateModifier

Author: mdb1

.gitignore

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+## User settings
+xcuserdata/
+
+# Swift Package Manager
+# Xcode automatically generates this directory with a .xcworkspacedata file and xcuserdata
+# hence it is not needed unless you have added a package configuration file to your project
+.swiftpm
+
+.build/

BuildTools/.swiftformat

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+# format options
+--allman false
+--indent 4
+--maxwidth 120
+--commas inline
+--decimalgrouping 3
+--wraparguments before-first
+
+# rules
+--enable isEmpty
+--disable redundantType
+--disable wrapMultilineStatementBraces

Package.swift

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+// swift-tools-version: 5.7
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "ViewStateController", platforms: [
+        .iOS(.v15),
+        .macOS(.v12)
+    ],
+    products: [
+        .library(
+            name: "ViewStateController",
+            targets: ["ViewStateController"]
+        )
+    ],
+    dependencies: [],
+    targets: [
+        .target(
+            name: "ViewStateController",
+            dependencies: []
+        ),
+        .testTarget(
+            name: "ViewStateControllerTests",
+            dependencies: ["ViewStateController"]
+        )
+    ]
+)

README.md

@@ -1,3 +1,18 @@
 # ViewStateController
 
 ViewStateController is a framework for Swift and SwiftUI developers that provides a simple and flexible way to manage the state of views that load information from a backend. It allows you to handle different states based on a historical array of states, and provides properties and methods to help you access and modify the state. With ViewStateController, you can easily implement complex views that depend on asynchronous data loading, and create a better user experience by showing loading spinners or error messages.
+
+## ViewStateController Object
+
+## WithViewState Modifier
+
+## Examples with code samples
+
+
+## BuildTools
+
+To run the formatter, just run:
+
+`.scripts/run-formatter.sh` from the root of the repository.
+
+YYou need to have `SwiftFormat` installed (`brew install swiftformat`).

Sources/ViewStateController/ErrorView/ErrorView.swift

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+//
+//  ErrorView.swift
+//  ViewStateController
+//
+//  Created by Manu on 26/02/2023.
+//
+
+import Foundation
+import SwiftUI
+
+/// Customizable error view with different types.
+public struct ErrorView: View {
+    private let type: ErrorViewType
+
+    /// Initializer
+    /// - Parameters:
+    ///   - type: The type to apply the style of the error state.
+    public init(type: ErrorViewType) {
+        self.type = type
+    }
+
+    /// Convenience initializer that applies the default error state.
+    /// - Parameter retryAction: The retry action for the button.
+    public init(retryAction: @escaping () -> Void) {
+        type = .vertical(
+            style: .init(
+                buttonOptions: .init(action: retryAction),
+                frameAlignment: .center
+            ),
+            alignment: .center
+        )
+    }
+
+    public var body: some View {
+        switch type {
+        case .emptyView:
+            EmptyView()
+        case let .vertical(style, alignment):
+            verticalView(style: style, alignment: alignment)
+        case let .horizontal(style, alignment):
+            horizontalView(style: style, alignment: alignment)
+        case let .custom(customView):
+            customView
+        }
+    }
+}
+
+private extension ErrorView {
+    @ViewBuilder
+    func verticalView(
+        style: ErrorViewStyle,
+        alignment: HorizontalAlignment
+    ) -> some View {
+        VStack(alignment: alignment) {
+            view(for: style)
+        }
+        .frame(maxWidth: .infinity, alignment: style.frameAlignment)
+    }
+
+    @ViewBuilder
+    func horizontalView(
+        style: ErrorViewStyle,
+        alignment: VerticalAlignment
+    ) -> some View {
+        HStack(alignment: alignment) {
+            view(for: style)
+        }
+        .frame(maxWidth: .infinity, alignment: style.frameAlignment)
+    }
+
+    @ViewBuilder
+    func view(for style: ErrorViewStyle) -> some View {
+        if let imageOptions = style.imageOptions {
+            Image(systemName: imageOptions.systemName)
+                .resizable()
+                .frame(
+                    width: imageOptions.frame.width,
+                    height: imageOptions.frame.height
+                )
+                .foregroundColor(imageOptions.foregroundColor)
+        }
+        if let titleOptions = style.titleOptions {
+            Text(titleOptions.text)
+                .font(titleOptions.font)
+                .foregroundColor(titleOptions.foregroundColor)
+        }
+        if let buttonOptions = style.buttonOptions {
+            Button(buttonOptions.text) {
+                buttonOptions.action()
+            }
+            .tint(buttonOptions.tintColor)
+            .foregroundColor(buttonOptions.foregroundColor)
+            .buttonStyle(.borderedProminent)
+            .font(buttonOptions.font)
+        }
+    }
+}
+
+/// Possible types of error view.
+public enum ErrorViewType {
+    /// Displays an EmptyView.
+    case emptyView
+    /// Displays a vertical stack with some customizable options:
+    /// Image (system name, color, frame)
+    /// Title (text, color, font)
+    /// Retry button (text, foreground/background color, font, action)
+    case vertical(
+        style: ErrorViewStyle,
+        alignment: HorizontalAlignment
+    )
+    /// Displays an horizontal stack with some customizable options:
+    /// Image (system name, color, frame)
+    /// Title (text, color, font)
+    /// Retry button (text, foreground/background color, font, action)
+    case horizontal(
+        style: ErrorViewStyle,
+        alignment: VerticalAlignment
+    )
+    /// Displays a custom view.
+    case custom(_ view: AnyView)
+}
+
+public struct ErrorViewStyle {
+    public struct ImageOptions {
+        let systemName: String
+        let foregroundColor: Color
+        let frame: CGSize
+
+        public init(
+            systemName: String = "xmark.circle.fill",
+            foregroundColor: Color = .red,
+            frame: CGSize = .init(width: 50, height: 50)
+        ) {
+            self.systemName = systemName
+            self.foregroundColor = foregroundColor
+            self.frame = frame
+        }
+    }
+
+    public struct TitleOptions {
+        let text: String
+        let foregroundColor: Color
+        let font: Font
+
+        public init(
+            text: String = "Something went wrong",
+            foregroundColor: Color = .primary,
+            font: Font = .callout
+        ) {
+            self.text = text
+            self.foregroundColor = foregroundColor
+            self.font = font
+        }
+    }
+
+    public struct ButtonOptions {
+        let text: String
+        let foregroundColor: Color
+        let tintColor: Color
+        let font: Font
+        let action: () -> Void
+
+        public init(
+            text: String = "Retry",
+            foregroundColor: Color = .white,
+            tintColor: Color = .accentColor,
+            font: Font = .callout,
+            action: @escaping () -> Void
+        ) {
+            self.text = text
+            self.foregroundColor = foregroundColor
+            self.tintColor = tintColor
+            self.font = font
+            self.action = action
+        }
+    }
+
+    let imageOptions: ImageOptions?
+    let titleOptions: TitleOptions?
+    let buttonOptions: ButtonOptions?
+    let frameAlignment: Alignment
+
+    public init(
+        imageOptions: ImageOptions? = .init(),
+        titleOptions: TitleOptions? = .init(),
+        buttonOptions: ButtonOptions?,
+        frameAlignment: Alignment = .center
+    ) {
+        self.imageOptions = imageOptions
+        self.titleOptions = titleOptions
+        self.buttonOptions = buttonOptions
+        self.frameAlignment = frameAlignment
+    }
+}

Sources/ViewStateController/ViewModifiers/AnyViewWrapper.swift

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+//
+//  AnyViewWrapper.swift
+//  ViewStateController
+//
+//  Created by Manu on 23/02/2023.
+//
+
+import SwiftUI
+
+public extension View {
+    /// Embeds the current view inside an AnyView.
+    func asAnyView() -> AnyView {
+        AnyView(self)
+    }
+}

Sources/ViewStateController/ViewModifiers/IfModifier.swift

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+//
+//  IfModifier.swift
+//  ViewStateController
+//
+//  Created by Manu on 27/02/2023.
+//
+
+import SwiftUI
+
+extension View {
+    /// Applies the given transform if the given condition evaluates to `true`.
+    /// - Parameters:
+    ///   - condition: The condition to evaluate.
+    ///   - transform: The transform to apply to the source `View`.
+    /// - Returns: Either the original `View` or the modified `View` if the condition is `true`.
+    @ViewBuilder
+    func `if`(_ condition: Bool, transform: (Self) -> some View) -> some View {
+        if condition {
+            transform(self)
+        } else {
+            self
+        }
+    }
+}