module advent_of_code.tasks.day_6.Star2

open System.IO

let stream = new StreamReader("tasks/day-6/input.txt")

let isNotNull (s: string) =
    s.Length > 0

let convertToInt64 (s: string) =
    s |> int64

let trimString (s: string) =
    s.Trim()

let rec buildArray (numberArray: string array array) (lineArray: string array) =
    if lineArray.Length = 0 then
        numberArray
    else
        let head, tail = lineArray[0], lineArray[1..]
        if lineArray[0] = "" then
            buildArray (Array.append numberArray [| [||] |]) tail
        else
            buildArray (Array.append numberArray[.. numberArray.Length - 2] [|(Array.append numberArray[numberArray.Length - 1] [| head |])|]) tail

let rec applyOps (allNumbers: string array array) (ops: string array) =
    if allNumbers.Length <> 0 then
        let currNumbers, numbersTail = allNumbers[0] |> Array.map convertToInt64, allNumbers[1..]
        let currOp, opsTail = ops[0], ops[1..]
        let result =
            match currOp with
            | "*" -> currNumbers |> Array.fold (*) (1 |> int64)
            | "+" -> Array.sum currNumbers
        result + applyOps numbersTail opsTail
    else
        0 |> int64

let main =
    let lines = stream.ReadToEnd().Split("\n")
    let ops = lines[lines.Length - 1].Split() |> Array.filter isNotNull
    let numberLines = (Array.transpose (lines[.. lines.Length - 2] |> Array.map Seq.toArray)) |> Array.map System.String |> Array.map trimString
    let numbers = buildArray [|[||]|] numberLines
    applyOps numbers ops