package com.example.aiapp

import androidx.compose.ui.geometry.Offset
import kotlin.test.Test
import kotlin.test.assertEquals

class SessionImageTest {
    @Test
    fun `zoom keeps the region panned to in the center`() {
        assertEquals(
            Offset(240f, -160f),
            zoomOffset(
                offset = Offset(120f, -80f),
                centroid = Offset(500f, 1000f),
                pan = Offset.Zero,
                oldScale = 2f,
                newScale = 4f,
                viewportCenter = Offset(500f, 1000f),
            ),
        )
    }

    @Test
    fun `zoom keeps an off-center pinch beneath moving fingers`() {
        assertEquals(
            Offset(460f, 420f),
            zoomOffset(
                offset = Offset(100f, -100f),
                centroid = Offset(250f, 400f),
                pan = Offset(10f, 20f),
                oldScale = 2f,
                newScale = 4f,
                viewportCenter = Offset(500f, 1000f),
            ),
        )
    }
}