library(GenomicRanges)

gr1 <- GRanges(c("chr1", "chr1"), IRanges(1, 5))
gr2 <- GRanges(c("chr1", "chr2"), IRanges(1, 5))
gr3 <- GRanges(c("chr3", "chr3", "chr3"), IRanges(1:3, 5))

test_Seqinfo_seqlevels_subset <- function()
{
    ## GRanges
    gr <- gr2
    seqlevels(gr, force=TRUE) <- "chr2"
    checkIdentical("chr2", seqlevels(gr))
    checkIdentical(1L, length(gr))
    gr <- suppressWarnings(c(gr1, gr2, gr3))

    ## GRangesList
    grl <- GRangesList(gr1, gr2, gr3)
    seqlevels(grl, force=TRUE) <- "chr1"
    checkIdentical("chr1", seqlevels(grl))
    checkIdentical(1L, length(grl))

    grl <- GRangesList(gr2)
    seqlevels(grl, force=TRUE) <- "chr1"
    checkIdentical(0L, length(grl))
}

test_Seqinfo_seqlevels_rename <- function()
{
    ## GRanges
    gr <- suppressWarnings(c(gr1, gr2, gr3)) 
    seqlevels(gr) <- gsub("chr", "CHR", seqlevels(gr))
    checkIdentical(c("CHR1", "CHR2", "CHR3"), seqlevels(gr))
    seqlevels(gr)[seqlevels(gr) == "CHR2"] <- "2"
    checkIdentical(c("CHR1", "2", "CHR3"), seqlevels(gr))
    new <- rev(seqlevels(gr))
    seqlevels(gr) <- new 
    checkIdentical(new, seqlevels(gr))

    ## GRangesList
    grl <- suppressWarnings(GRangesList(gr1, gr2, gr3))
    idx <- seqlevels(grl) == "chr2"
    checkException(seqlevels(grl)[idx] <- "chr1", silent=TRUE)
    seqlevels(grl)[seqlevels(grl) == "chr3"] <- "3"
    checkIdentical(c("chr1", "chr2", "3"), seqlevels(grl))
}

test_Seqinfo_seqlevels_drop_add <- function()
{
    grl <- GRangesList(gr1, gr2, gr3)

    new_seqlevels <- setdiff(seqlevels(grl), "chr1")
    checkException(seqlevels(grl) <- new_seqlevels, silent=TRUE)

    target <- GRangesList(GRanges("chr3", IRanges(1:3, 5),
    seqinfo=Seqinfo(c("chr2", "chr3"))))
    seqlevels(grl, force=TRUE) <- new_seqlevels
    checkIdentical(target, grl)

    grl <- grl0 <- GRangesList(gr1, gr2, gr3)
    checkException(seqlevels(grl) <- c(seqlevels(grl), "chr2"), silent=TRUE)
    seqlevels(grl) <- c(seqlevels(grl), "chrX")
    checkIdentical(c("chr1", "chr2", "chr3", "chrX"), seqlevels(grl))

    new_seqlevels <- setdiff(seqlevels(grl), "chrX")
    seqlevels(grl) <- new_seqlevels
    checkIdentical(grl0, grl) 
}
test_Seqinfo.merge <- function()
{
    x <- Seqinfo(seqnames=c("chr1", "chr2", "chr3", "chrM"),
                 seqlengths=c(100, 200, NA, 15),
                 isCircular=c(NA, FALSE, FALSE, TRUE))
    checkIdentical(merge(x), x)
    checkIdentical(merge(x, NULL), x)
    checkIdentical(merge(NULL, x), x)
    checkIdentical(merge(x, Seqinfo()), x)
    checkIdentical(merge(Seqinfo(), x), x)
    checkIdentical(merge(x, x), x)
    checkIdentical(merge(x, Seqinfo(rev(names(seqlengths)))), x)

    y <- Seqinfo(seqnames=c("chrM", "chr4", "chr3"),
                 seqlengths=c(15, NA, 300))
    got <- merge(x, y)
    want <- Seqinfo(seqnames=c("chr1", "chr2", "chr3", "chrM", "chr4"),
                    seqlengths=c(100, 200, 300, 15, NA),
                    isCircular=c(NA, FALSE, FALSE, TRUE, NA))
    checkIdentical(got, want)

    ## This contradicts what 'x' says about circularity of chr3 and chrM:
    isCircular(y)[c("chr3", "chrM")] <- c(TRUE, FALSE)
    checkException(merge(x, y), silent=TRUE)
}

