import SwiftUI

struct DictionaryView: View {
    @StateObject private var viewModel = DictionaryViewModel()

    private let panelBackground = Color(red: 0.96, green: 0.97, blue: 0.98)

    var body: some View {
        GeometryReader { proxy in
            let dynamicHorizontalPadding = min(max(proxy.size.width * 0.045, AppTheme.contentPadding), 52)
            let dynamicBottomPadding = min(max(proxy.size.height * 0.06, 28), 56)

            ScrollView(.vertical, showsIndicators: false) {
                VStack(alignment: .leading, spacing: 0) {
                    header
                        .padding(.bottom, 28)

                    contentCard
                        .padding(.bottom, 24)

                    if viewModel.hasResult {
                        resultCard
                    }
                }
                .frame(maxWidth: 1200, alignment: .topLeading)
                .frame(maxWidth: .infinity, alignment: .topLeading)
                .padding(.horizontal, dynamicHorizontalPadding)
                .padding(.top, AppTheme.brandLabelTopInset)
                .padding(.bottom, dynamicBottomPadding)
            }
        }
        .onChange(of: viewModel.query) { newValue in
            if newValue.count > DictionaryViewModel.maxQueryLength {
                viewModel.query = String(newValue.prefix(DictionaryViewModel.maxQueryLength))
            }
            if viewModel.hasResult {
                viewModel.resetResult()
            }
        }
    }

    private var header: some View {
        HStack(alignment: .top) {
            VStack(alignment: .leading, spacing: 8) {
                Text("Dictionary")
                    .font(.system(size: 30, weight: .bold))
                    .foregroundStyle(AppTheme.textPrimary)

                HStack(spacing: 0) {
                    Text("Find ")
                        .foregroundStyle(AppTheme.textSecondary)
                    Text("meaning")
                        .fontWeight(.semibold)
                        .foregroundStyle(AppTheme.teal)
                    Text(". Learn ")
                        .foregroundStyle(AppTheme.textSecondary)
                    Text("words")
                        .fontWeight(.semibold)
                        .foregroundStyle(AppTheme.teal)
                    Text(". Expand your ")
                        .foregroundStyle(AppTheme.textSecondary)
                    Text("vocabulary")
                        .fontWeight(.semibold)
                        .foregroundStyle(AppTheme.teal)
                    Text(".")
                        .foregroundStyle(AppTheme.textSecondary)
                }
                .font(.system(size: 15))
            }

            Spacer()

            IconButton {
                SettingsGearIcon()
            } action: {}
            .accessibilityLabel("Settings")
        }
    }

    private var contentCard: some View {
        VStack(alignment: .leading, spacing: 18) {
            Image("YourContentLogo")
                .resizable()
                .aspectRatio(contentMode: .fit)
                .frame(height: 52, alignment: .topLeading)
                .frame(height: 46, alignment: .topLeading)
                .clipped()
                .accessibilityLabel("Your Content")

            searchField

            if let errorMessage = viewModel.errorMessage {
                errorBanner(errorMessage)
            }

            if viewModel.isLoading {
                loadingState
            } else if !viewModel.hasResult {
                emptyState
            }

            if !viewModel.recentSearches.isEmpty {
                recentSearchesSection
            }
        }
        .padding(22)
        .background(AppTheme.cardBackground)
        .clipShape(RoundedRectangle(cornerRadius: AppTheme.cardCornerRadius))
        .overlay(
            RoundedRectangle(cornerRadius: AppTheme.cardCornerRadius)
                .stroke(AppTheme.border, lineWidth: 1)
        )
        .shadow(color: AppTheme.cardShadow, radius: 16, y: 6)
    }

    private var searchField: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Look up a word")
                .font(.system(size: 13, weight: .semibold))
                .foregroundStyle(AppTheme.textSecondary)

            HStack(spacing: 10) {
                HStack(spacing: 10) {
                    Image(systemName: "magnifyingglass")
                        .font(.system(size: 14, weight: .medium))
                        .foregroundStyle(AppTheme.textMuted)

                    TextField("Type a word and press Return...", text: $viewModel.query, onCommit: viewModel.lookUp)
                        .textFieldStyle(.plain)
                        .font(.system(size: 16))
                        .foregroundStyle(AppTheme.textPrimary)
                }
                .padding(.horizontal, 16)
                .padding(.vertical, 14)
                .background(Color.white)
                .clipShape(RoundedRectangle(cornerRadius: AppTheme.inputCornerRadius))
                .overlay(
                    RoundedRectangle(cornerRadius: AppTheme.inputCornerRadius)
                        .stroke(AppTheme.inputBorder, lineWidth: 1)
                )

                Button(action: viewModel.lookUp) {
                    HStack(spacing: 8) {
                        Image(systemName: "book.fill")
                            .font(.system(size: 13, weight: .semibold))

                        Text("Look Up")
                            .font(.system(size: 14, weight: .semibold))
                    }
                    .foregroundStyle(.white)
                    .padding(.horizontal, 20)
                    .padding(.vertical, 14)
                    .background(viewModel.canLookUp ? AppTheme.primaryGradient : LinearGradient(colors: [AppTheme.border, AppTheme.border], startPoint: .leading, endPoint: .trailing))
                    .clipShape(RoundedRectangle(cornerRadius: AppTheme.inputCornerRadius))
                }
                .buttonStyle(.plain)
                .disabled(!viewModel.canLookUp)
            }

            HStack(spacing: 8) {
                ToolbarButton(title: "Paste Word", iconName: "doc.on.clipboard") {
                    viewModel.pasteWord()
                }

                Spacer()

                ClearButton {
                    viewModel.clearSearch()
                }
            }
        }
    }

    private var emptyState: some View {
        VStack(spacing: 12) {
            Image(systemName: "text.book.closed")
                .font(.system(size: 34))
                .foregroundStyle(AppTheme.teal.opacity(0.45))

            Text("Search for any English word to see definitions, examples, and synonyms.")
                .font(.system(size: 14))
                .foregroundStyle(AppTheme.textSecondary)
                .multilineTextAlignment(.center)
                .frame(maxWidth: 420)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, 28)
        .padding(.horizontal, 20)
        .background(panelBackground)
        .clipShape(RoundedRectangle(cornerRadius: AppTheme.inputCornerRadius))
        .overlay(
            RoundedRectangle(cornerRadius: AppTheme.inputCornerRadius)
                .stroke(AppTheme.border.opacity(0.6), lineWidth: 1)
        )
    }

    private var loadingState: some View {
        HStack(spacing: 12) {
            ProgressView()
                .controlSize(.small)

            Text("Looking up definition...")
                .font(.system(size: 14))
                .foregroundStyle(AppTheme.textSecondary)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(18)
        .background(panelBackground)
        .clipShape(RoundedRectangle(cornerRadius: AppTheme.inputCornerRadius))
    }

    private func errorBanner(_ message: String) -> some View {
        HStack(spacing: 10) {
            Image(systemName: "exclamationmark.triangle.fill")
                .font(.system(size: 14))
                .foregroundStyle(AppTheme.clearForeground)

            Text(message)
                .font(.system(size: 14))
                .foregroundStyle(AppTheme.clearForeground)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(.horizontal, 16)
        .padding(.vertical, 12)
        .background(AppTheme.clearBackground)
        .clipShape(RoundedRectangle(cornerRadius: 10))
        .overlay(
            RoundedRectangle(cornerRadius: 10)
                .stroke(AppTheme.clearBorder, lineWidth: 1)
        )
    }

    private var recentSearchesSection: some View {
        VStack(alignment: .leading, spacing: 10) {
            Text("Recent Searches")
                .font(.system(size: 13, weight: .semibold))
                .foregroundStyle(AppTheme.textSecondary)

            LazyVGrid(
                columns: [GridItem(.adaptive(minimum: 72), spacing: 8)],
                alignment: .leading,
                spacing: 8
            ) {
                ForEach(viewModel.recentSearches, id: \.self) { word in
                    Button {
                        viewModel.lookUpRecent(word)
                    } label: {
                        Text(word)
                            .font(.system(size: 13, weight: .medium))
                            .foregroundStyle(AppTheme.teal)
                            .padding(.horizontal, 12)
                            .padding(.vertical, 7)
                            .background(AppTheme.tealLight)
                            .clipShape(Capsule())
                    }
                    .buttonStyle(.plain)
                }
            }
        }
    }

    private var resultCard: some View {
        Group {
            if let entry = viewModel.entry {
                VStack(alignment: .leading, spacing: 20) {
                    wordHeader(entry)

                    ForEach(entry.meanings) { meaning in
                        meaningSection(meaning)
                    }
                }
                .padding(22)
                .background(AppTheme.cardBackground)
                .clipShape(RoundedRectangle(cornerRadius: AppTheme.cardCornerRadius))
                .overlay(
                    RoundedRectangle(cornerRadius: AppTheme.cardCornerRadius)
                        .stroke(AppTheme.border, lineWidth: 1)
                )
                .shadow(color: AppTheme.cardShadow, radius: 16, y: 6)
            }
        }
    }

    private func wordHeader(_ entry: DictionaryEntry) -> some View {
        HStack(alignment: .top, spacing: 16) {
            VStack(alignment: .leading, spacing: 6) {
                Text(entry.word)
                    .font(.system(size: 34, weight: .bold))
                    .foregroundStyle(AppTheme.textPrimary)

                if let phonetic = entry.phonetic {
                    Text(phonetic)
                        .font(.system(size: 16))
                        .foregroundStyle(AppTheme.textSecondary)
                }
            }

            Spacer()

            Button {
                viewModel.playPronunciation(for: entry)
            } label: {
                HStack(spacing: 8) {
                    Image(systemName: "speaker.wave.2.fill")
                        .font(.system(size: 13, weight: .semibold))

                    Text("Listen")
                        .font(.system(size: 13, weight: .semibold))
                }
                .foregroundStyle(AppTheme.teal)
                .padding(.horizontal, 14)
                .padding(.vertical, 9)
                .background(AppTheme.tealLight)
                .clipShape(RoundedRectangle(cornerRadius: 10))
            }
            .buttonStyle(.plain)
            .accessibilityLabel("Play pronunciation")
        }
    }

    private func meaningSection(_ meaning: DictionaryMeaning) -> some View {
        VStack(alignment: .leading, spacing: 14) {
            PartOfSpeechBadge(title: meaning.partOfSpeech)

            VStack(alignment: .leading, spacing: 12) {
                ForEach(Array(meaning.definitions.enumerated()), id: \.element.id) { index, definition in
                    definitionRow(number: index + 1, definition: definition)
                }
            }

            if !meaning.synonyms.isEmpty {
                relatedWordsSection(title: "Synonyms", words: meaning.synonyms)
            }

            if !meaning.antonyms.isEmpty {
                relatedWordsSection(title: "Antonyms", words: meaning.antonyms)
            }
        }
        .padding(18)
        .frame(maxWidth: .infinity, alignment: .leading)
        .background(panelBackground)
        .clipShape(RoundedRectangle(cornerRadius: AppTheme.cardCornerRadius))
        .overlay(
            RoundedRectangle(cornerRadius: AppTheme.cardCornerRadius)
                .stroke(AppTheme.border.opacity(0.6), lineWidth: 1)
        )
    }

    private func definitionRow(number: Int, definition: DictionaryDefinition) -> some View {
        VStack(alignment: .leading, spacing: 6) {
            HStack(alignment: .top, spacing: 10) {
                Text("\(number).")
                    .font(.system(size: 14, weight: .semibold))
                    .foregroundStyle(AppTheme.teal)
                    .frame(width: 20, alignment: .leading)

                Text(definition.text)
                    .font(.system(size: 14))
                    .foregroundStyle(AppTheme.textPrimary)
                    .fixedSize(horizontal: false, vertical: true)
            }

            if let example = definition.example {
                Text("\"\(example)\"")
                    .font(.system(size: 13))
                    .italic()
                    .foregroundStyle(AppTheme.textMuted)
                    .padding(.leading, 30)
            }
        }
    }

    private func relatedWordsSection(title: String, words: [String]) -> some View {
        VStack(alignment: .leading, spacing: 8) {
            Text(title)
                .font(.system(size: 12, weight: .semibold))
                .foregroundStyle(AppTheme.textSecondary)

            LazyVGrid(
                columns: [GridItem(.adaptive(minimum: 72), spacing: 8)],
                alignment: .leading,
                spacing: 8
            ) {
                ForEach(words, id: \.self) { word in
                    Button {
                        viewModel.lookUpRecent(word)
                    } label: {
                        Text(word)
                            .font(.system(size: 12, weight: .medium))
                            .foregroundStyle(AppTheme.textSecondary)
                            .padding(.horizontal, 10)
                            .padding(.vertical, 6)
                            .background(Color.white)
                            .clipShape(Capsule())
                            .overlay(
                                Capsule()
                                    .stroke(AppTheme.border.opacity(0.7), lineWidth: 1)
                            )
                    }
                    .buttonStyle(.plain)
                }
            }
        }
        .padding(.top, 4)
    }
}

private struct PartOfSpeechBadge: View {
    let title: String

    var body: some View {
        Text(title.capitalized)
            .font(.system(size: 12, weight: .semibold))
            .foregroundStyle(AppTheme.teal)
            .padding(.horizontal, 12)
            .padding(.vertical, 6)
            .background(AppTheme.tealLight)
            .clipShape(Capsule())
    }
}