/*
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * MIT License
 *
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package third.parties.fresco

import android.graphics.Canvas
import android.graphics.Paint
import android.graphics.Paint.FontMetricsInt
import android.graphics.Rect
import android.graphics.drawable.Drawable
import android.text.style.ReplacementSpan
import androidx.annotation.IntDef

/**
 * A better implementation of image spans that also supports centering images against the text.
 *
 * In order to migrate from ImageSpan, replace `new ImageSpan(drawable, alignment)` with
 * `new BetterImageSpan(drawable, BetterImageSpan.normalizeAlignment(alignment))`.
 *
 * There are 2 main differences between BetterImageSpan and ImageSpan:
 * 1. Pass in ALIGN_CENTER to center images against the text.
 * 2. ALIGN_BOTTOM no longer unnecessarily increases the size of the text:
 * DynamicDrawableSpan (ImageSpan's parent) adjusts sizes as if alignment was ALIGN_BASELINE
 * which can lead to unnecessary whitespace.
 */
open class BetterImageSpan @JvmOverloads constructor(
    val drawable: Drawable,
    @param:BetterImageSpanAlignment private val mAlignment: Int = ALIGN_BASELINE
) : ReplacementSpan() {
    @IntDef(*[ALIGN_BASELINE, ALIGN_BOTTOM, ALIGN_CENTER])
    @Retention(AnnotationRetention.SOURCE)
    annotation class BetterImageSpanAlignment

    private var mWidth = 0
    private var mHeight = 0
    private var mBounds: Rect? = null
    private val mFontMetricsInt = FontMetricsInt()

    init {
        updateBounds()
    }

    /**
     * Returns the width of the image span and increases the height if font metrics are available.
     */
    override fun getSize(
        paint: Paint,
        text: CharSequence,
        start: Int,
        end: Int,
        fontMetrics: FontMetricsInt?
    ): Int {
        updateBounds()
        if (fontMetrics == null) {
            return mWidth
        }
        val offsetAbove = getOffsetAboveBaseline(fontMetrics)
        val offsetBelow = mHeight + offsetAbove
        if (offsetAbove < fontMetrics.ascent) {
            fontMetrics.ascent = offsetAbove
        }
        if (offsetAbove < fontMetrics.top) {
            fontMetrics.top = offsetAbove
        }
        if (offsetBelow > fontMetrics.descent) {
            fontMetrics.descent = offsetBelow
        }
        if (offsetBelow > fontMetrics.bottom) {
            fontMetrics.bottom = offsetBelow
        }
        return mWidth
    }

    override fun draw(
        canvas: Canvas,
        text: CharSequence,
        start: Int,
        end: Int,
        x: Float,
        top: Int,
        y: Int,
        bottom: Int,
        paint: Paint
    ) {
        paint.getFontMetricsInt(mFontMetricsInt)
        val iconTop = y + getOffsetAboveBaseline(mFontMetricsInt)
        canvas.translate(x, iconTop.toFloat())
        drawable.draw(canvas)
        canvas.translate(-x, -iconTop.toFloat())
    }

    private fun updateBounds() {
        mBounds = drawable.bounds
        mWidth = mBounds!!.width()
        mHeight = mBounds!!.height()
    }

    private fun getOffsetAboveBaseline(fm: FontMetricsInt): Int {
        return when (mAlignment) {
            ALIGN_BOTTOM -> fm.descent - mHeight
            ALIGN_CENTER -> {
                val textHeight = fm.descent - fm.ascent
                val offset = (textHeight - mHeight) / 2
                fm.ascent + offset
            }
            ALIGN_BASELINE -> -mHeight
            else -> -mHeight
        }
    }

    companion object {
        const val ALIGN_BOTTOM = 0
        const val ALIGN_BASELINE = 1
        const val ALIGN_CENTER = 2
    }
}