import os
import strings
import benchmark

const max_iterations = os.getenv_opt('MAX_ITERATIONS') or { '100_000' }.int()

fn imin(x u16, y u16) u16 {
    return if x < y { x } else { y }
}

// From https://gist.github.com/zeozeozeo/f785910173f3115163bffd0c5240de07
@[direct_array_access]
pub fn zeozeozeo_levenshtein_distance(a string, b string) int {
    if a == '' {
        return b.len
    }
    if b == '' {
        return a.len
    }
    if a == b {
        return 0
    }

    mut row := []u16{len: a.len + 1}
    for i in 1 .. row.len {
        row[i] = i
    }

    for i := 1; i < b.len; i++ {
        mut prev := u16(i)
        for j := 1; j < a.len; j++ {
            mut current := row[j - 1] // match
            if b[i - 1] != a[j - 1] {
                // insertion, substitution, deletion
                current = imin(imin(row[j - 1] + 1, prev + 1), row[j] + 1)
            }
            row[j - 1] = prev
            prev = current
        }
        row[a.len] = prev
    }

    return row[a.len]
}

fn main() {
    a := 'abcdef'
    b := 'abdef'

    mut sum := i64(0)
    mut bench := benchmark.start()
    sum = 0
    for _ in 0 .. max_iterations {
        sum += i64(strings.levenshtein_distance(a, b))
    }
    bench.measure('strings.levenshtein_distance: ${sum}')

    sum = 0
    for _ in 0 .. max_iterations {
        sum += i64(zeozeozeo_levenshtein_distance(a, b))
    }
    bench.measure('zeozeozeo_levenshtein_distance: ${sum}')

    mut fsum := f64(0)
    for _ in 0 .. max_iterations {
        fsum += strings.dice_coefficient(a, b)
    }
    bench.measure('strings.dice_coefficient: ${fsum}')
}