//
//  AddReactionView.swift
//  Tusker
//
//  Created by Shadowfacts on 4/17/24.
//  Copyright © 2024 Shadowfacts. All rights reserved.
//

import SwiftUI
import Pachyderm
import TuskerComponents

struct AddReactionView: View {
    let mastodonController: MastodonController
    let addReaction: (Reaction) async throws -> Void
    @Environment(\.dismiss) private var dismiss
    @ScaledMetric private var emojiSize = 30
    @State private var allEmojis: [Emoji] = []
    @State private var emojisBySection: [String: [Emoji]] = [:]
    @State private var query = ""
    @State private var error: (any Error)?
    
    var body: some View {
        NavigationView {
            ScrollView(.vertical) {
                LazyVGrid(columns: [GridItem(.adaptive(minimum: emojiSize), spacing: 4)]) {
                    if query.count == 1 {
                        Section {
                            AddReactionButton {
                                await doAddReaction(.emoji(query))
                            } label: {
                                Text(query)
                                    .font(.system(size: 25))
                            }
                            .buttonStyle(.plain)
                        }
                    }
                    
                    ForEach(emojisBySection.keys.sorted(), id: \.self) { section in
                        Section {
                            ForEach(emojisBySection[section]!, id: \.shortcode) { emoji in
                                AddReactionButton {
                                    await doAddReaction(.custom(emoji))
                                } label: {
                                    CustomEmojiImageView(emoji: emoji)
                                        .frame(height: emojiSize)
                                        .accessibilityLabel(emoji.shortcode)
                                }
                            }
                        } header: {
                            if !section.isEmpty {
                                VStack(alignment: .leading, spacing: 2) {
                                    Text(section)
                                        .font(.caption)
                                    
                                    Divider()
                                }
                                .padding(.top, 4)
                            }
                        }
                    }
                }
                .padding(.horizontal)
            }
            .searchable(text: $query, placement: .navigationBarDrawer(displayMode: .always))
            .searchPresentationToolbarBehaviorIfAvailable()
            .onChange(of: query) { _ in
                updateFilteredEmojis()
            }
            .navigationTitle("Add Reaction")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button(role: .cancel) {
                        dismiss()
                    } label: {
                        Text("Cancel")
                    }
                }
            }
        }
        .navigationViewStyle(.stack)
        .mediumPresentationDetentIfAvailable()
        .alertWithData("Error Adding Reaction", data: $error, actions: { _ in
            Button("OK") {}
        }, message: { error in
            Text(error.localizedDescription)
        })
        .task {
            allEmojis = await mastodonController.getCustomEmojis()
            updateFilteredEmojis()
        }
    }
    
    private func updateFilteredEmojis() {
        let filteredEmojis = if !query.isEmpty {
            allEmojis.map { emoji -> (Emoji, (matched: Bool, score: Int)) in
                (emoji, FuzzyMatcher.match(pattern: query, str: emoji.shortcode))
            }
            .filter(\.1.matched)
            .sorted { $0.1.score > $1.1.score }
            .map(\.0)
        } else {
            allEmojis
        }
        
        var shortcodes = Set<String>()
        var newEmojis = [Emoji]()
        var newEmojisBySection = [String: [Emoji]]()
        for emoji in filteredEmojis where !shortcodes.contains(emoji.shortcode) {
            newEmojis.append(emoji)
            shortcodes.insert(emoji.shortcode)
            
            let category = emoji.category ?? ""
            if newEmojisBySection.keys.contains(category) {
                newEmojisBySection[category]!.append(emoji)
            } else {
                newEmojisBySection[category] = [emoji]
            }
        }
        emojisBySection = newEmojisBySection
    }
    
    private func doAddReaction(_ reaction: Reaction) async {
        try! await Task.sleep(nanoseconds: NSEC_PER_SEC)
        do {
            try await addReaction(reaction)
            dismiss()
        } catch {
            self.error = error
        }
    }
    
    enum Reaction {
        case emoji(String)
        case custom(Emoji)
    }
}

private struct AddReactionButton<Label: View>: View {
    let addReaction: () async -> Void
    @ViewBuilder let label: Label
    @State private var isLoading = false
    
    var body: some View {
        Button {
            isLoading = true
            Task {
                await addReaction()
                isLoading = false
            }
        } label: {
            ZStack {
                label
                    .opacity(isLoading ? 0 : 1)
                
                if isLoading {
                    ProgressView()
                }
            }
        }
        .padding(2)
        .hoverEffect()
    }
}

private extension View {
    @available(iOS, obsoleted: 16.0)
    @ViewBuilder
    func mediumPresentationDetentIfAvailable() -> some View {
        if #available(iOS 16.0, *) {
            self.presentationDetents([.medium, .large])
        } else {
            self
        }
    }
    
    @available(iOS, obsoleted: 17.1)
    @ViewBuilder
    func searchPresentationToolbarBehaviorIfAvailable() -> some View {
        if #available(iOS 17.1, *) {
            self.searchPresentationToolbarBehavior(.avoidHidingContent)
        } else {
            self
        }
    }
}

//#Preview {
//    AddReactionView()
//}