library(knitr)
library(kableExtra)

ellipse_table <- function(df, nr = 5, nc = 5, format = "latex") {
    nrows <- nrow(df)
    ncols <- ncol(df)

    # Ellipsis symbols depending on format
    if (format == "latex") {
        h_ellipsis <- "$\\dots$" # horizontal (for columns)
        v_ellipsis <- "$\\vdots$" # vertical (for rows)
    } else {
        h_ellipsis <- "..."
        v_ellipsis <- "..."
    }

    # Select top/bottom rows
    row_idx <- c(
        seq_len(ceiling(nr / 2)),
        nrows - floor(nr / 2) + 1:nr - nr
    )
    row_idx <- unique(pmax(pmin(row_idx, nrows), 1)) # clamp

    # Select left/right cols
    col_idx <- c(
        seq_len(ceiling(nc / 2)),
        ncols - floor(nc / 2) + 1:nc - nc
    )
    col_idx <- unique(pmax(pmin(col_idx, ncols), 1))

    # Subset
    sub_df <- df[row_idx, col_idx, drop = FALSE]

    # Insert ellipsis row if needed
    if (nrows > nr) {
        ellipsis_row <- as.list(rep(h_ellipsis, length(col_idx)))
        sub_df <- rbind(
            sub_df[1:ceiling(nr / 2), , drop = FALSE],
            ellipsis_row,
            sub_df[(ceiling(nr / 2) + 1):nrow(sub_df), , drop = FALSE]
        )
        rownames(sub_df)[ceiling(nr / 2) + 1] <- v_ellipsis
    }

    # Insert ellipsis col if needed
    if (ncols > nc) {
        ellipsis_col <- rep(v_ellipsis, nrow(sub_df))
        sub_df <- cbind(
            sub_df[, 1:ceiling(nc / 2), drop = FALSE],
            "..." = ellipsis_col,
            sub_df[, (ceiling(nc / 2) + 1):ncol(sub_df), drop = FALSE]
        )
        names(sub_df)[ceiling(nc / 2) + 1] <- h_ellipsis
    }

    # Print with kable
    return(sub_df)
}