module _11

open System
open System.IO

let rightTrans = (0, 1)
let downTrans = (1, 0)
let sidewayRightTrans = (1, 1)
let sidewayLeftTrans = (1, -1)

let len = 4

let maximum max v = if v > max then v else max

let maxProduct =

    let getData = 
        let lines = File.ReadAllLines(@"11.txt")

        let convertDataRow(line:string) =
            line.Split(' ') |> Array.map int

        lines |> Array.map convertDataRow

    let rows = getData

    let rowLen = rows.Length
    let colLen = rows.[0].Length

    let getAdjacentCells (r, c) (rInc, cInc) =
        if (r + rInc*len > rowLen 
            || c + cInc*len > colLen
            || c + cInc*len < 0) then
            Seq.empty
        else
            Seq.init len (fun i -> rows.[r + rInc*i].[c + cInc*i])

    seq{
        for r in 0..rowLen-1 do
        for c in 0..colLen-1 do
            let getCells = getAdjacentCells (r, c)

            let product = Seq.fold (*) 1

            yield getCells rightTrans |> product
            yield getCells downTrans |> product
            yield getCells sidewayRightTrans |> product
            yield getCells sidewayLeftTrans |> product 
        }
        |> Seq.fold maximum -1

(*
for row in rows do
    for cell in row do
        printf "%u " cell
    printf "\n"
*)