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(PostList.background)
    }
}

struct PostList: View {

    static let background = Color(r: 2, g: 15, b: 26)

    @Binding
    var posts: [Post]

    var body: some View {
        List {
            if posts.isEmpty {
                CenteredPost {
                    Text("No posts yet.")
                        .padding()
                }
                .listRowSeparator(.hidden)
            }
            CenteredPost {
                Button(action: addNewPost) {
                    Text("Add post")
                }
                .padding()
                .listRowSeparator(.hidden)
            }
            ForEach(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(PostList.background)
        .scrollContentBackground(.hidden)
    }

    private func addNewPost() {
        let largestId = posts.map { $0.id }.max() ?? 0

        let post = Post(
            id: largestId + 1,
            isDraft: true,
            startDate: .now,
            endDate: nil,
            title: .init(en: "Title", de: "Titel"),
            text: .init(en: "Text", de: "Text"),
            tags: [],
            images: [])
        posts.insert(post, at: 0)
    }
}

#Preview {
    PostList(posts: .constant([.mock, .fullMock]))
}