import {Vector} from './Vector.js'
import {NotAType, Returns, Undefined} from '#core/Type.js'
import {Any, match} from '#core/TypePatterns.js'

export const promoteUnary = name => match(Vector, (math, V, strategy) => {
   if (V.Component === NotAType) {
      // have to resolve element by element :-(
      return Returns(V, v => v.map(
         elt => math.resolve(name, math.typeOf(elt), strategy)(elt)))
   }
   const compOp = math.resolve(name, V.Component, strategy)
   return Returns(Vector(compOp.returns), v => v.map(elt => compOp(elt)))
})

export const promoteBinary = name => [
   match([Vector, Any], (math, [V, E], strategy) => {
      const VComp = V.Component
      if (VComp === NotAType) {
         return Returns(V, (v, e) => v.map(
            f => math.resolve(name, [math.typeOf(f), E], strategy)(f, e)))
      }
      const compOp = math.resolve(name, [VComp, E], strategy)
      return Returns(
         Vector(compOp.returns), (v, e) => v.map(f => compOp(f, e)))
   }),
   match([Any, Vector], (math, [E, V], strategy) => {
      const VComp = V.Component
      if (VComp === NotAType) {
         return Returns(V, (e, v) => v.map(
            f => math.resolve(name, [E, math.typeOf(f)], strategy)(e, f)))
      }
      const compOp = math.resolve(name, [E, VComp], strategy)
      return Returns(
         Vector(compOp.returns, (e, v) => v.map(f => compOp(e, f))))
   }),
   match([Vector, Vector], (math, [V, W], strategy) => {
      const VComp = V.Component
      const WComp = W.Component
      let compOp
      let opNoV
      let opNoW
      let ReturnType
      if (VComp === NotAType || WComp === NotAType) {
         const typ = math.typeOf
         compOp = (v, w) => {
            return math.resolve(name, [typ(v), typ(w)], strategy)(v, w)
         }
         opNoV = compOp
         opNoW = compOp
         ReturnType = Vector(NotAType)
      } else {
         compOp = math.resolve(name, [VComp, WComp], strategy)
         opNoV = math.resolve(name, [Undefined, WComp], strategy)
         opNoW = math.resolve(name, [VComp, Undefined], strategy)
         ReturnType = Vector(compOp.returns)
      }
      return Returns(
         ReturnType,
         (v, w) => {
            const vInc = Number(v.length > 1)
            const wInc = Number(w.length >= v.length || w.length > 1)
            const retval = []
            let vIx = 0
            let wIx = 0
            while ((vInc && vIx < v.length)
                   || (wInc && wIx < w.length)
            ) {
               if (vIx >= v.length) {
                  retval.push(opNoV(undefined, w[wIx]))
               } else if (wIx >= w.length) {
                  retval.push(opNoW(v[vIx], undefined))
               } else retval.push(compOp(v[vIx], w[wIx]))
               vIx += vInc
               wIx += wInc
            }
            return retval
         })
   })
]