//
// Copyright 2021 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 SwiftUI

struct RoundedBorderTextField: View {
    // MARK: - Properties
    
    var title: String?
    let placeHolder: String
    @Binding var text: String
    var footerText: String?
    var isError = false
    var isFirstResponder = false

    var configuration = UIKitTextInputConfiguration()
    @State var isSecureTextVisible = false
    
    var onTextChanged: ((String) -> Void)?
    var onEditingChanged: ((Bool) -> Void)?
    var onCommit: (() -> Void)?

    // MARK: Private
    
    @State private var isEditing = false
    
    @Environment(\.theme) private var theme: ThemeSwiftUI
    @Environment(\.isEnabled) private var isEnabled
    
    // MARK: Public
    
    var body: some View {
        VStack(alignment: .leading, spacing: -1) {
            if let title = self.title {
                Text(title)
                    .foregroundColor(theme.colors.primaryContent)
                    .font(theme.fonts.subheadline)
                    .multilineTextAlignment(.leading)
                    .padding(.bottom, 8)
            }
            
            ZStack(alignment: .leading) {
                if text.isEmpty {
                    Text(placeHolder)
                        .font(theme.fonts.callout)
                        .foregroundColor(theme.colors.tertiaryContent)
                        .lineLimit(1)
                        .accessibilityHidden(true)
                }
                
                ThemableTextField(placeholder: "",
                                  text: $text,
                                  configuration: configuration,
                                  isSecureTextVisible: $isSecureTextVisible) { isEditing in
                    self.isEditing = isEditing
                    onEditingChanged?(isEditing)
                } onCommit: {
                    onCommit?()
                }
                .makeFirstResponder(isFirstResponder)
                .addButton(isEnabled)
                .onChange(of: text) { newText in
                    onTextChanged?(newText)
                }
                .frame(height: 30)
                .allowsHitTesting(isEnabled)
                .opacity(isEnabled ? 1 : 0.5)
                .accessibilityLabel(text.isEmpty ? placeHolder : "")
            }
            .padding(EdgeInsets(top: 8, leading: 8, bottom: 8, trailing: text.isEmpty ? 8 : 0))
            .background(RoundedRectangle(cornerRadius: 8).fill(theme.colors.background))
            .overlay(RoundedRectangle(cornerRadius: 8).stroke(borderColor, lineWidth: borderWidth))

            if let footerText = self.footerText {
                Text(footerText)
                    .foregroundColor(isError ? theme.colors.alert : theme.colors.tertiaryContent)
                    .font(theme.fonts.footnote)
                    .multilineTextAlignment(.leading)
                    .padding(.top, 8)
                    .transition(.opacity)
            }
        }
        .animation(.easeOut(duration: 0.2))
    }
    
    /// The text field's border color.
    private var borderColor: Color {
        if isEditing {
            return theme.colors.accent
        } else if footerText != nil, isError {
            return theme.colors.alert
        } else {
            return theme.colors.quinaryContent
        }
    }
    
    /// The text field's border width.
    private var borderWidth: CGFloat {
        isEditing || (footerText != nil && isError) ? 2 : 1
    }
}

// MARK: - Previews

struct TextFieldWithError_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            sampleView.theme(.light).preferredColorScheme(.light)
            sampleView.theme(.dark).preferredColorScheme(.dark)
        }
        .padding()
    }
    
    static var sampleView: some View {
        VStack(alignment: .center, spacing: 20) {
            RoundedBorderTextField(title: "A title", placeHolder: "A placeholder", text: .constant(""), footerText: nil, isError: false)
            RoundedBorderTextField(placeHolder: "A placeholder", text: .constant("Some text"), footerText: nil, isError: false)
            RoundedBorderTextField(title: "A title", placeHolder: "A placeholder", text: .constant("Some very long text used to check overlapping with the delete button"), footerText: "Some error text", isError: true)
            RoundedBorderTextField(title: "A title", placeHolder: "A placeholder", text: .constant("Some very long text used to check overlapping with the delete button"), footerText: "Some normal text", isError: false)
            RoundedBorderTextField(title: "A title", placeHolder: "A placeholder", text: .constant("Some very long text used to check overlapping with the delete button"), footerText: "Some normal text", isError: false)
                .disabled(true)
            
            Spacer().frame(height: 0)
            
            RoundedBorderTextField(title: "Password", placeHolder: "Enter your password", text: .constant(""), configuration: UIKitTextInputConfiguration(isSecureTextEntry: true))
            RoundedBorderTextField(title: "Password", placeHolder: "Enter your password", text: .constant("password"), configuration: UIKitTextInputConfiguration(isSecureTextEntry: true))
        }
    }
}