import SwiftUI

/// Milestones and their progress.
struct MilestoneListView: View {

    @State private var model: MilestoneListViewModel

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

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

            ForEach(model.state.value ?? []) { milestone in
                MilestoneRow(milestone: milestone)
            }
        }
        .overlay { LoadStateOverlay(state: model.state) }
        .navigationTitle("Milestones")
        .navigationBarTitleDisplayMode(.inline)
        .task { await model.load() }
        .refreshable { await model.load() }
    }
}

private struct MilestoneRow: View {
    let milestone: Milestone

    private var total: Int { milestone.open + milestone.closed }
    private var fraction: Double {
        total == 0 ? 0 : Double(milestone.closed) / Double(total)
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 5) {
            HStack(spacing: 6) {
                Text(milestone.title)
                    .font(.gbSans(.subheadline).weight(.medium))
                if milestone.state != "open" {
                    GBChip(milestone.state, .gbDone)
                }
                Spacer()
                if let due = milestone.due, !due.isEmpty {
                    Text(due)
                        .font(.gbSans(.caption))
                        .foregroundStyle(.tertiary)
                }
            }
            if let description = milestone.description, !description.isEmpty {
                Text(description)
                    .font(.gbSans(.caption))
                    .foregroundStyle(.secondary)
                    .lineLimit(2)
            }
            if total > 0 {
                ProgressView(value: fraction)
                    .tint(.gbAccent)
                Text("\(milestone.closed) of \(total) closed")
                    .font(.gbSans(.caption2))
                    .foregroundStyle(.secondary)
            }
        }
        .padding(.vertical, 2)
    }
}