package com.example.aiapp

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

class SessionImageTest {
    @Test
    fun `a full-height image hides both bars`() {
        assertEquals(
            ViewerBars(status = true, navigation = true),
            viewerBars(
                imageWidth = 1000,
                imageHeight = 2000,
                viewportWidth = 1000,
                viewportHeight = 2000,
                scale = 1f,
                offset = Offset.Zero,
                insets = ViewerBarInsets(status = 100, navigation = 100),
            ),
        )
    }

    @Test
    fun `a letterboxed image leaves both bars visible`() {
        assertEquals(
            ViewerBars(),
            viewerBars(
                imageWidth = 1000,
                imageHeight = 500,
                viewportWidth = 1000,
                viewportHeight = 2000,
                scale = 1f,
                offset = Offset.Zero,
                insets = ViewerBarInsets(status = 100, navigation = 100),
            ),
        )
    }

    @Test
    fun `panning into the status bar hides only that bar`() {
        assertEquals(
            ViewerBars(status = true),
            viewerBars(
                imageWidth = 1000,
                imageHeight = 500,
                viewportWidth = 1000,
                viewportHeight = 2000,
                scale = 2f,
                offset = Offset(0f, -500f),
                insets = ViewerBarInsets(status = 100, navigation = 100),
            ),
        )
    }

    @Test
    fun `native scale reverses fitting a tall image`() {
        assertEquals(
            1.25f,
            nativeScale(
                imageWidth = 1000,
                imageHeight = 2000,
                viewportWidth = 1000,
                viewportHeight = 1600,
            ),
        )
    }

    @Test
    fun `native scale leaves a small image alone`() {
        assertEquals(
            1f,
            nativeScale(
                imageWidth = 500,
                imageHeight = 500,
                viewportWidth = 1000,
                viewportHeight = 1000,
            ),
        )
    }

    @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),
            ),
        )
    }
}