package com.example.aiapp

import java.time.Duration
import kotlin.test.Test
import kotlin.test.assertEquals

/**
 * The two ways a span of time is written here, and the rule each of them follows.
 *
 * Both are read off a screen to make a decision -- how long a tool call may take, how long a quota
 * has left -- so what matters is that the shortest form that answers the question is what appears.
 */
class DurationsTest {
    @Test
    fun `under a minute is the largest unit alone`() {
        assertEquals("30ms", formatMillis(30))
        assertEquals("999ms", formatMillis(999))
        assertEquals("1s", formatMillis(1000))
        assertEquals("2.5s", formatMillis(2500))
        // One decimal, rounded rather than cut: 2.46s is nearer two and a half than two and four.
        assertEquals("2.5s", formatMillis(2460))
        assertEquals("59.9s", formatMillis(59_900))
    }

    @Test
    fun `a minute or more is every unit that has something in it`() {
        // The figure this rule was written for: a tool timeout, which arrives as milliseconds and
        // is unreadable as 480000.
        assertEquals("8m", formatMillis(480_000))
        assertEquals("1m", formatMillis(60_000))
        assertEquals("1m 30s", formatMillis(90_000))
        assertEquals("5d 12h 4m", formatMillis(475_440_000))
        // Empty units are left out rather than written as zero: the labels say which is which,
        // and "5d 0h 4m" is only longer.
        assertEquals("5d 4m", formatMillis(432_240_000))
    }

    @Test
    fun `only a whole number of milliseconds is rewritten`() {
        assertEquals("8m", formatMillisText(" 480000 "))
        // A timeout a tool expressed some other way is its own words, passed through rather than
        // guessed at.
        assertEquals("2 minutes", formatMillisText("2 minutes"))
        assertEquals("", formatMillisText(""))
    }

    @Test
    fun `a countdown rounds up, so it never reports a minute already spent`() {
        assertEquals("3h 13m", formatSpan(Duration.ofMinutes(192).plusSeconds(50)))
        // Exactly on a minute is already the answer and is not pushed past it.
        assertEquals("3h 12m", formatSpan(Duration.ofMinutes(192)))
        assertEquals("12m", formatSpan(Duration.ofMinutes(12)))
        // Rounding up carries, so a day's worth of minutes reads as a day.
        assertEquals("1d 0h", formatSpan(Duration.ofHours(23).plusMinutes(59).plusSeconds(30)))
    }
}