package org.terst.feedreader.data

import org.junit.Assert.assertEquals
import org.junit.Test

class SettingsTest {

    @Test
    fun `pinch zoom with scale factor of 1 leaves the font size unchanged`() {
        assertEquals(18, pinchZoomFontSizePx(18, 1.0f))
    }

    @Test
    fun `pinching out scales the font size up, rounded to the nearest pixel`() {
        assertEquals(22, pinchZoomFontSizePx(20, 1.1f))
    }

    @Test
    fun `pinching in scales the font size down, rounded to the nearest pixel`() {
        assertEquals(16, pinchZoomFontSizePx(20, 0.8f))
    }

    @Test
    fun `pinch zoom result is clamped to the minimum reader font size`() {
        assertEquals(READER_FONT_SIZE_RANGE_PX.first, pinchZoomFontSizePx(14, 0.3f))
    }

    @Test
    fun `pinch zoom result is clamped to the maximum reader font size`() {
        assertEquals(READER_FONT_SIZE_RANGE_PX.last, pinchZoomFontSizePx(28, 3.0f))
    }

    @Test
    fun `text already laid out at the wanted size needs no zoom`() {
        assertEquals(UNZOOMED_TEXT_ZOOM_PERCENT, readerTextZoomPercent(renderedPx = 18, targetPx = 18))
    }

    @Test
    fun `a bigger wanted size lifts the text zoom proportionally`() {
        assertEquals(156, readerTextZoomPercent(renderedPx = 18, targetPx = 28))
    }

    @Test
    fun `a smaller wanted size drops the text zoom proportionally`() {
        assertEquals(78, readerTextZoomPercent(renderedPx = 18, targetPx = 14))
    }

    @Test
    fun `text zoom is measured against the size the page is laid out at, not the saved size`() {
        // Pinch, release, pinch again before the reload at the new size has landed: the page is
        // still laid out at 18px even though 22px is the saved size, so going on to 24px has to
        // be 24/18 -- measuring it against the saved 22px would visibly shrink the text first.
        assertEquals(133, readerTextZoomPercent(renderedPx = 18, targetPx = 24))
    }
}