untag

//// The type `Or` is an type union with no wrapping.
//// `Or2(Int, String, Float)` is the same as `Int | String | Float`, 
//// not `{Left, Int} | {Right, {Left, String} | {Right, Float}}`

import gleam/dynamic
import gleam/dynamic/decode.{type Decoder} as dec

@external(erlang, "untag_ffi", "id")
@external(javascript, "untag_ffi.mjs", "id")
@internal
pub fn id(x: a) -> b

pub fn to_dynamic(or: Or(a, b)) -> dynamic.Dynamic {
  id(or)
}

pub fn decode(this or, with decoder: Decoder(_)) {
  or |> to_dynamic |> dec.run(decoder)
}

pub type Or(t1, t2)

pub type Or2(t1, t2, t3) =
  Or(t1, Or(t2, t3))

pub type Or3(a, b, c, d) =
  Or(a, Or2(b, c, d))

pub type Or4(a, b, c, d, e) =
  Or(a, Or3(b, c, d, e))

pub type Or5(a, b, c, d, e, f) =
  Or(a, Or4(b, c, d, e, f))

pub type Or6(a, b, c, d, e, f, g) =
  Or(a, Or5(b, c, d, e, f, g))

pub type Or7(a, b, c, d, e, f, g, h) =
  Or(a, Or6(b, c, d, e, f, g, h))

pub type Or8(a, b, c, d, e, f, g, h, i) =
  Or(a, Or7(b, c, d, e, f, g, h, i))

pub type Or9(a, b, c, d, e, f, g, h, i, j) =
  Or(a, Or8(b, c, d, e, f, g, h, i, j))

pub const head: fn(h) -> Or(h, _) = id

pub const tail: fn(t) -> Or(_, t) = id

fn tail_in(tn, x) {
  tn(tail(x))
}

pub const tail_2nd = tail

pub fn tail_3rd(x) {
  tail_2nd |> tail_in(x)
}

pub fn tail_4th(x) {
  tail_3rd |> tail_in(x)
}

pub fn tail_5th(x) {
  tail_4th |> tail_in(x)
}

pub fn tail_6th(x) {
  tail_5th |> tail_in(x)
}

pub fn tail_7th(x) {
  tail_6th |> tail_in(x)
}

pub fn tail_8th(x) {
  tail_7th |> tail_in(x)
}

pub fn tail_9th(x) {
  tail_8th |> tail_in(x)
}

pub fn tail_10th(x) {
  tail_9th |> tail_in(x)
}

fn head_in(tn, x) {
  tn(head(x))
}

/// h_<n>th = become nth head
pub const head_1st = head

pub fn head_2nd(x) {
  tail_2nd |> head_in(x)
}

pub fn head_3th(x) {
  tail_3rd |> head_in(x)
}

pub fn head_4th(x) {
  tail_4th |> head_in(x)
}

pub fn head_5th(x) {
  tail_5th |> head_in(x)
}

pub fn head_6th(x) {
  tail_6th |> head_in(x)
}

pub fn head_7th(x) {
  tail_7th |> head_in(x)
}

pub fn head_8th(x) {
  tail_8th |> head_in(x)
}

pub fn head_9th(x) {
  tail_9th |> head_in(x)
}

pub fn head_10th(x) {
  tail_10th |> head_in(x)
}

pub fn flip(or: Or(a, b)) -> Or(b, a) {
  id(or)
}

pub fn flip_tail(or: Or(t1, Or(t2, t3))) -> Or(t1, Or(t3, t2)) {
  id(or)
}

pub fn flip_head(or) {
  or |> flipped(flip_tail)
}

pub fn flipped(or, f) {
  or |> flip |> f |> flip
}

pub fn give(or: Or(Or(t1, t2), t3)) -> Or(t2, Or(t1, t3)) {
  id(or)
}

pub fn give2(or) {
  or |> give |> give
}

pub fn give3(or) {
  or |> give |> give2
}

pub fn give4(or) {
  or |> give |> give3
}

pub fn give5(or) {
  or |> give |> give4
}

pub fn give6(or) {
  or |> give |> give5
}

pub fn give7(or) {
  or |> give |> give6
}

pub fn give8(or) {
  or |> give |> give7
}

pub fn take(or: Or(t1, Or(t2, t3))) -> Or(Or(t2, t1), t3) {
  or |> flipped(give)
}

pub fn take2(or) {
  or |> take |> take
}

pub fn take3(or) {
  or |> take |> take2
}

pub fn take4(or) {
  or |> take |> take3
}

pub fn take5(or) {
  or |> take |> take4
}

pub fn take6(or) {
  or |> take |> take5
}

pub fn take7(or) {
  or |> take |> take6
}

pub fn take8(or) {
  or |> take |> take7
}

pub fn rev3_with_tail(or) {
  or |> flip |> give
}

pub fn rev4_with_tail(or) {
  or |> rev3_with_tail |> give
}

pub fn rev5_with_tail(or) {
  or |> rev4_with_tail |> give
}

pub fn rev6_with_tail(or) {
  or |> rev5_with_tail |> give
}

pub fn rev7_with_tail(or) {
  or |> rev6_with_tail |> give
}

pub fn rev8_with_tail(or) {
  or |> rev7_with_tail |> give
}

pub fn rev9_with_tail(or) {
  or |> rev8_with_tail |> give
}

pub fn rev10_with_tail(or) {
  or |> rev9_with_tail |> give
}