use dioxus::prelude::*;

#[component]
pub fn Pagination(
    current_page: u64,
    total_pages: u64,
    on_page_change: EventHandler<u64>,
) -> Element {
    if total_pages <= 1 {
        return rsx! {};
    }

    let pages = pagination_range(current_page, total_pages);

    rsx! {
        div { class: "pagination",
            button {
                class: "btn btn-sm btn-secondary",
                disabled: current_page == 0,
                onclick: move |_| {
                    if current_page > 0 {
                        on_page_change.call(current_page - 1);
                    }
                },
                "Prev"
            }

            for page in pages {
                if page == u64::MAX {
                    span { class: "page-ellipsis", "..." }
                } else {
                    {
                        let btn_class = if page == current_page {
                            "btn btn-sm btn-primary page-btn"
                        } else {
                            "btn btn-sm btn-ghost page-btn"
                        };
                        rsx! {
                            button {
                                key: "page-{page}",
                                class: "{btn_class}",
                                onclick: move |_| on_page_change.call(page),
                                "{page + 1}"
                            }
                        }
                    }
                }
            }

            button {
                class: "btn btn-sm btn-secondary",
                disabled: current_page >= total_pages - 1,
                onclick: move |_| {
                    if current_page < total_pages - 1 {
                        on_page_change.call(current_page + 1);
                    }
                },
                "Next"
            }
        }
    }
}

/// Compute a range of page numbers to display (with ellipsis as u64::MAX).
pub fn pagination_range(current: u64, total: u64) -> Vec<u64> {
    let mut pages = Vec::new();
    if total <= 7 {
        for i in 0..total {
            pages.push(i);
        }
        return pages;
    }

    pages.push(0);

    if current > 2 {
        pages.push(u64::MAX);
    }

    let start = if current <= 2 { 1 } else { current - 1 };
    let end = if current >= total - 3 {
        total - 1
    } else {
        current + 2
    };

    for i in start..end {
        if !pages.contains(&i) {
            pages.push(i);
        }
    }

    if current < total - 3 {
        pages.push(u64::MAX);
    }

    if !pages.contains(&(total - 1)) {
        pages.push(total - 1);
    }

    pages
}