import SwiftUI

/// Activity on everything you can reach — the `feed` command, paginated.
struct FeedView: View {

    @State private var list: PagedListModel<FeedEvent>

    init(client: GitbayClient) {
        _list = State(initialValue: PagedListModel(
            client: client,
            argv: ["feed"],
            emptyMessage: "Nothing has happened yet on repositories you can reach."
        ))
    }

    var body: some View {
        List {
            ForEach(list.state.value ?? []) { event in
                link(for: event)
            }
            PageFooter(list: list)
        }
        .overlay { LoadStateOverlay(state: list.state) }
        .navigationTitle("Feed")
        .toolbar { AccountMenu() }
        .task {
            if list.state.value == nil {
                await list.reload()
            }
        }
        .refreshable { await list.reload() }
    }

    @ViewBuilder
    private func link(for event: FeedEvent) -> some View {
        switch event.destination {
        case .repo(let repo):
            NavigationLink(value: RepoRoute.repo(repo)) { FeedRow(event: event) }
        case .mr(let repo, let number):
            NavigationLink(value: MRRoute.mr(repo: repo, number: number)) { FeedRow(event: event) }
        case .issue(let repo, let number):
            NavigationLink(value: IssueRoute.issue(repo: repo, number: number)) { FeedRow(event: event) }
        case .build(let repo, let number):
            NavigationLink(value: BuildRoute.log(repo: repo, number: number)) { FeedRow(event: event) }
        case .release(let repo, let tag):
            NavigationLink(value: ReleaseRoute.release(repo: repo, tag: tag)) { FeedRow(event: event) }
        case nil:
            FeedRow(event: event)
        }
    }
}

private struct FeedRow: View {
    let event: FeedEvent

    var body: some View {
        HStack(spacing: 10) {
            Image(systemName: event.icon.name)
                .foregroundStyle(color)
                .frame(width: 22)
            VStack(alignment: .leading, spacing: 2) {
                Text(event.repo)
                    .font(.caption)
                    .foregroundStyle(.secondary)
                HStack(spacing: 4) {
                    if let actor = event.actor, !actor.isEmpty {
                        Text(actor)
                            .font(.subheadline.weight(.semibold))
                    }
                    Text(event.phrase)
                        .font(.subheadline)
                        .lineLimit(1)
                }
            }
            Spacer()
            Text(event.createdAt, format: .relative(presentation: .named))
                .font(.caption)
                .foregroundStyle(.tertiary)
        }
        .padding(.vertical, 2)
    }

    private var color: Color {
        switch event.icon.isPositive {
        case true: .green
        case false: .red
        default: .secondary
        }
    }
}