import type { evaluate, isAny, List } from "../../../dev/utils/src/main.js"
import type { MorphAst, Out } from "../tuple.js"

export type inferIntersection<l, r> = [l] extends [never]
    ? never
    : [r] extends [never]
    ? never
    : [l & r] extends [never]
    ? never
    : isAny<l | r> extends true
    ? any
    : l extends MorphAst<infer lIn, infer lOut>
    ? r extends MorphAst
        ? never
        : (In: evaluate<lIn & r>) => Out<lOut>
    : r extends MorphAst<infer rIn, infer rOut>
    ? (In: evaluate<rIn & l>) => Out<rOut>
    : intersectObjects<l, r> extends infer result
    ? result
    : never

type intersectObjects<l, r> = [l, r] extends [object, object]
    ? [l, r] extends [infer lList extends List, infer rList extends List]
        ? inferArrayIntersection<lList, rList>
        : evaluate<{
              [k in keyof l | keyof r]: k extends keyof l
                  ? k extends keyof r
                      ? inferIntersection<l[k], r[k]>
                      : l[k]
                  : r[k & keyof r]
          }>
    : l & r

type inferArrayIntersection<
    l extends List,
    r extends List,
    result extends List = []
> = [l, r] extends [
    [infer lHead, ...infer lTail],
    [infer rHead, ...infer rTail]
]
    ? inferArrayIntersection<
          lTail,
          rTail,
          [...result, inferIntersection<lHead, rHead>]
      >
    : l extends [infer lHead, ...infer lTail]
    ? r extends []
        ? // l is longer tuple than r, unsatisfiable
          never
        : inferArrayIntersection<
              lTail,
              r,
              [...result, inferIntersection<lHead, r[number]>]
          >
    : r extends [infer rHead, ...infer rTail]
    ? l extends []
        ? // r is longer tuple than l, unsatisfiable
          never
        : inferArrayIntersection<
              l,
              rTail,
              [...result, inferIntersection<l[number], rHead>]
          >
    : [number, number] extends [l["length"], r["length"]]
    ? [...result, ...inferIntersection<l[number], r[number]>[]]
    : result