nominal donor_a = ()
nominal hg38 = ()
nominal chr1 = ()
nominal raw = ()
nominal normalized = ()
nominal merged = ()

union callset sample build contig phase =
    | RawCallset :: forall sample build contig. string -> callset sample build contig raw
    | NormalizedCallset :: forall sample build contig. string -> callset sample build contig normalized
    | MergedCallset :: forall sample build contig. string -> callset sample build contig merged

union normalization sample build contig from to =
    | NormalizeLeft :: forall sample build contig. normalization sample build contig raw normalized
    | NormalizeRight :: forall sample build contig. normalization sample build contig raw normalized

union merge_input sample build contig =
    | MergeInput :: forall sample build contig.
        callset sample build contig normalized * callset sample build contig normalized
        -> merge_input sample build contig

union rec normalization_plan sample build contig from to =
    | NormalizeLeaf :: forall sample build contig from to.
        normalization sample build contig from to
        -> normalization_plan sample build contig from to
    | NormalizeThen :: forall sample build contig from to.
        (exists middle.
            normalization_plan sample build contig from middle
            * normalization sample build contig middle to)
        -> normalization_plan sample build contig from to

inl normalize forall sample build contig.
    (step : normalization sample build contig raw normalized)
    (calls : callset sample build contig raw)
    : callset sample build contig normalized =
    match step, calls with
    | NormalizeLeft, RawCallset label => NormalizedCallset label
    | NormalizeRight, RawCallset label => NormalizedCallset label

inl merge_calls forall sample build contig.
    (input : merge_input sample build contig)
    : callset sample build contig merged =
    match input with
    | MergeInput (NormalizedCallset _, NormalizedCallset _) => MergedCallset "merged-calls"

inl label forall sample build contig. (calls : callset sample build contig merged) : string =
    match calls with
    | MergedCallset value => value

inl main () : string =
    inl left : callset donor_a hg38 chr1 raw = RawCallset "left"
    inl right : callset donor_a hg38 chr1 raw = RawCallset "right"
    inl left' = normalize NormalizeLeft left
    inl right' = normalize NormalizeRight right
    label (merge_calls (MergeInput (left', right')))