import SwiftUI


private struct CenteredPost<Content>: View where Content: View {

    let content: Content

    init(@ViewBuilder content: () -> Content) {
        self.content = content()
    }

    var body: some View {
        HorizontalCenter {
            content
        }
        .listRowBackground(ColorPalette.listBackground)
    }
}

struct PostList: View {

    @EnvironmentObject
    private var content: Content

    var body: some View {
        List {
            if content.posts.isEmpty {
                CenteredPost {
                    Text("No posts yet.")
                        .padding()
                }
                .listRowSeparator(.hidden)
            }
            CenteredPost {
                Button(action: addNewPost) {
                    Text("Add post")
                }
                .padding()
                .listRowSeparator(.hidden)
            }
            ForEach(content.posts) { post in
                CenteredPost {
                    PostView(post: post)
                        .frame(maxWidth: 600)
                }
                .listRowSeparator(.hidden)
                .listRowInsets(.init(top: 0, leading: 0, bottom: 30, trailing: 0))
            }
        }
        .listStyle(.plain)
        .background(ColorPalette.listBackground)
        .scrollContentBackground(.hidden)
    }

    private func addNewPost() {
        let post = Post(
            id: "new",
            isDraft: true,
            createdDate: .now,
            startDate: .now,
            endDate: nil,
            tags: [],
            german: .init(title: "Titel", content: "Text"),
            english: .init(title: "Title", content: "Text"))
        content.posts.insert(post, at: 0)
    }
}

#Preview {
    PostList()
        .environmentObject(Content())
}