//
//  ComposeToolbar.swift
//  Tusker
//
//  Created by Shadowfacts on 11/12/22.
//  Copyright © 2022 Shadowfacts. All rights reserved.
//

import SwiftUI
import Pachyderm
import TuskerComponents

struct ComposeToolbar: View {
    static let height: CGFloat = 44
    private static let visibilityOptions: [MenuPicker.Option] = Visibility.allCases.map { vis in
            .init(value: vis, title: vis.displayName, subtitle: vis.subtitle, image: UIImage(systemName: vis.unfilledImageName), accessibilityLabel: "Visibility: \(vis.displayName)")
    }
    
    @ObservedObject var draft: OldDraft
    
    @EnvironmentObject private var uiState: ComposeUIState
    @EnvironmentObject private var mastodonController: MastodonController
    @ObservedObject private var preferences = Preferences.shared
    @ScaledMetric(relativeTo: .body) private var imageSize: CGFloat = 22
    @State private var minWidth: CGFloat?
    @State private var realWidth: CGFloat?
    
    var body: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            HStack(spacing: 0) {
                Button("CW") {
                    draft.contentWarningEnabled.toggle()
                }
                .accessibilityLabel(draft.contentWarningEnabled ? "Remove content warning" : "Add content warning")
                .padding(5)
                .hoverEffect()
                
                MenuPicker(selection: $draft.visibility, options: Self.visibilityOptions, buttonStyle: .iconOnly)
//                    // the button has a bunch of extra space by default, but combined with what we add it's too much
                    .padding(.horizontal, -8)
                
                if mastodonController.instanceFeatures.localOnlyPosts {
                    MenuPicker(selection: $draft.localOnly, options: [
                        .init(value: true, title: "Local-only", subtitle: "Only \(mastodonController.accountInfo!.instanceURL.host!)", image: UIImage(named: "link.broken")),
                        .init(value: false, title: "Federated", image: UIImage(systemName: "link"))
                    ], buttonStyle: .iconOnly)
                    .padding(.horizontal, -8)
                }
                
                if let currentInput = uiState.currentInput, currentInput.toolbarElements.contains(.emojiPicker) {
                    Button(action: self.emojiPickerButtonPressed) {
                        Label("Insert custom emoji", systemImage: "face.smiling")
                    }
                    .labelStyle(.iconOnly)
                    .font(.system(size: imageSize))
                    .padding(5)
                    .hoverEffect()
                    .transition(.opacity.animation(.linear(duration: 0.2)))
                }
                
                if let currentInput = uiState.currentInput,
                   currentInput.toolbarElements.contains(.formattingButtons),
                   preferences.statusContentType != .plain {
                    Spacer()
                    
                    ForEach(StatusFormat.allCases, id: \.rawValue) { format in
                        Button(action: self.formatAction(format)) {
                            if let imageName = format.imageName {
                                Image(systemName: imageName)
                                    .font(.system(size: imageSize))
                            } else if let (str, attrs) = format.title {
                                let container = try! AttributeContainer(attrs, including: \.uiKit)
                                Text(AttributedString(str, attributes: container))
                            }
                        }
                        .accessibilityLabel(format.accessibilityLabel)
                        .padding(5)
                        .hoverEffect()
                        .transition(.opacity.animation(.linear(duration: 0.2)))
                    }
                }
                
                Spacer()
            }
            .padding(.horizontal, 16)
            .frame(minWidth: minWidth)
            .background(GeometryReader { proxy in
                Color.clear
                    .preference(key: ToolbarWidthPrefKey.self, value: proxy.size.width)
                    .onPreferenceChange(ToolbarWidthPrefKey.self) { width in
                        realWidth = width
                    }
            })
        }
        .scrollDisabledIfAvailable(realWidth ?? 0 <= minWidth ?? 0)
        .frame(height: Self.height)
        .frame(maxWidth: .infinity)
        .background(.regularMaterial, ignoresSafeAreaEdges: .bottom)
        .overlay(alignment: .top) {
            Divider()
        }
        .background(GeometryReader { proxy in
            Color.clear
                .preference(key: ToolbarWidthPrefKey.self, value: proxy.size.width)
                .onPreferenceChange(ToolbarWidthPrefKey.self) { width in
                    minWidth = width
                }
        })
    }
    
    private func emojiPickerButtonPressed() {
        guard uiState.autocompleteState == nil else {
            return
        }
        uiState.shouldEmojiAutocompletionBeginExpanded = true
        uiState.currentInput?.beginAutocompletingEmoji()
    }
    
    private func formatAction(_ format: StatusFormat) -> () -> Void {
        {
            uiState.currentInput?.applyFormat(format)
        }
    }
}

private struct ToolbarWidthPrefKey: PreferenceKey {
    static var defaultValue: CGFloat? = nil
    static func reduce(value: inout CGFloat?, nextValue: () -> CGFloat?) {
        value = nextValue()
    }
}

private extension View {
    @available(iOS, obsoleted: 16.0)
    @ViewBuilder
    func scrollDisabledIfAvailable(_ disabled: Bool) -> some View {
        if #available(iOS 16.0, *) {
            self.scrollDisabled(disabled)
        } else {
            self
        }
    }
}

struct ComposeToolbar_Previews: PreviewProvider {
    static var previews: some View {
        ComposeToolbar(draft: OldDraft(accountID: ""))
    }
}