import SwiftUI

/// Where a name is defined, from the repository's symbol index. A result
/// opens the file at its line on the default branch, the one indexed.
struct SymbolSearchView: View {

    @State private var model: SymbolSearchViewModel
    @State private var query: String
    private let initialQuery: String?

    init(client: GitbayClient, repo: String, query: String? = nil) {
        _model = State(initialValue: SymbolSearchViewModel(client: client, repoPath: repo))
        _query = State(initialValue: query ?? "")
        initialQuery = query
    }

    var body: some View {
        List {
            ForEach(model.state?.value ?? []) { symbol in
                NavigationLink(value: RepoRoute.file(
                    repo: model.repoPath, path: symbol.path, ref: nil, line: symbol.line
                )) {
                    VStack(alignment: .leading, spacing: 3) {
                        HStack(spacing: 6) {
                            Text(symbol.name)
                                .font(.gbMono(.subheadline).weight(.medium))
                                .lineLimit(1)
                            GBChip(symbol.kind, .secondary)
                        }
                        Text("\(symbol.path):\(symbol.line)")
                            .font(.gbMono(.caption))
                            .foregroundStyle(.secondary)
                            .lineLimit(1)
                            .truncationMode(.head)
                    }
                    .accessibilityElement(children: .combine)
                }
                .accessibilityIdentifier("symbol-\(symbol.name)")
            }
        }
        .overlay {
            if let state = model.state {
                LoadStateOverlay(state: state)
            } else {
                ContentUnavailableView {
                    Label("Find a definition", systemImage: "function")
                } description: {
                    Text("A name or its start, on the default branch.")
                }
            }
        }
        .searchable(text: $query, prompt: "Find a definition")
        .onSubmit(of: .search) {
            Task { await model.search(query) }
        }
        .toolbar {
            ToolbarItem(placement: .topBarTrailing) {
                Menu {
                    Picker("Kind", selection: Binding(get: { model.kind }, set: { model.kind = $0 })) {
                        Text("Any kind").tag(String?.none)
                        ForEach(SymbolSearchViewModel.kinds, id: \.self) { kind in
                            Text(kind).tag(String?.some(kind))
                        }
                    }
                } label: {
                    Image(systemName: model.kind == nil
                          ? "line.3.horizontal.decrease.circle" : "line.3.horizontal.decrease.circle.fill")
                }
                .accessibilityLabel(model.kind.map { "Kind: \($0)" } ?? "Kind: any")
                .accessibilityIdentifier("symbols-kind")
            }
        }
        .onChange(of: model.kind) {
            if !query.trimmingCharacters(in: .whitespaces).isEmpty {
                Task { await model.search(query) }
            }
        }
        .task {
            if let initialQuery, model.state == nil { await model.search(initialQuery) }
        }
        .navigationTitle("Definitions")
        .navigationBarTitleDisplayMode(.inline)
    }
}