import SwiftUI

struct IssueListView: View {

    @State private var model: IssueListViewModel
    @State private var createModel: IssueCreateViewModel
    @State private var composing = false
    @State private var draftTitle = ""
    @State private var draftBody = ""

    init(client: GitbayClient, repo: String) {
        _model = State(initialValue: IssueListViewModel(client: client, repoPath: repo))
        _createModel = State(initialValue: IssueCreateViewModel(client: client, repoPath: repo))
    }

    var body: some View {
        List {
            Picker("State", selection: Bindable(model).filter) {
                ForEach(IssueListViewModel.StateFilter.allCases) { filter in
                    Text(filter.rawValue.capitalized).tag(filter)
                }
            }
            .pickerStyle(.segmented)
            .listRowBackground(Color.clear)
            .listRowInsets(EdgeInsets())

            ForEach(model.state.value ?? []) { issue in
                NavigationLink(value: IssueRoute.issue(repo: model.repoPath, number: issue.number)) {
                    IssueRow(issue: issue)
                }
            }
            PageFooter(list: model.list)
        }
        .overlay { LoadStateOverlay(state: model.state) }
        .navigationTitle("Issues")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .topBarTrailing) {
                Button {
                    composing = true
                } label: {
                    Image(systemName: "plus")
                }
                .accessibilityIdentifier("issue-create-button")
            }
        }
        .sheet(isPresented: $composing) {
            ComposeSheet(
                heading: "New Issue",
                submitLabel: "Create",
                working: createModel.working,
                errorMessage: createModel.errorMessage,
                title: $draftTitle,
                bodyText: $draftBody
            ) {
                Task {
                    if await createModel.create(title: draftTitle, body: draftBody) != nil {
                        draftTitle = ""
                        draftBody = ""
                        composing = false
                        await model.load()
                    }
                }
            }
        }
        .task { await model.load() }
        .refreshable { await model.load() }
    }
}

private struct IssueRow: View {
    let issue: Issue

    var body: some View {
        VStack(alignment: .leading, spacing: 4) {
            HStack(alignment: .firstTextBaseline, spacing: 6) {
                Text("#\(issue.number)")
                    .font(.gbMono(.caption))
                    .foregroundStyle(.secondary)
                Text(issue.title)
                    .font(.gbSans(.subheadline).weight(.medium))
                    .lineLimit(2)
            }
            HStack(spacing: 6) {
                Image(systemName: issue.isOpen ? "circle" : "checkmark.circle.fill")
                    .font(.gbSans(.caption2))
                    .foregroundStyle(issue.isOpen ? Color.gbOK : Color.gbBad)
                ForEach(issue.labels ?? [], id: \.self) { label in
                    GBChip(label, .secondary)
                }
                Spacer()
                if let assignees = issue.assignees, !assignees.isEmpty {
                    Text(assignees.joined(separator: ", "))
                        .font(.gbSans(.caption))
                        .foregroundStyle(.secondary)
                        .lineLimit(1)
                }
                Text(issue.createdAt, format: .relative(presentation: .named))
                    .font(.gbSans(.caption))
                    .foregroundStyle(.secondary)
            }
        }
        .padding(.vertical, 2)
    }
}

nonisolated enum IssueRoute: Hashable {
    case list(repo: String)
    case issue(repo: String, number: Int64)
}