From 5f2f3a00e49e4c08dba2ae2f093e0476a8f012f9 Mon Sep 17 00:00:00 2001
From: Kevin Boulongne <kevin.boulongne@infomaniak.com>
Date: Thu, 19 Dec 2024 08:01:38 +0100
Subject: [PATCH] feat: Add `FormatterFileSize`

---
 .../com/infomaniak/core2/FormatterFileSize.kt | 107 ++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 Core2/src/main/java/com/infomaniak/core2/FormatterFileSize.kt

diff --git a/Core2/src/main/java/com/infomaniak/core2/FormatterFileSize.kt b/Core2/src/main/java/com/infomaniak/core2/FormatterFileSize.kt
new file mode 100644
index 000000000..65dabb604
--- /dev/null
+++ b/Core2/src/main/java/com/infomaniak/core2/FormatterFileSize.kt
@@ -0,0 +1,107 @@
+/*
+ * Infomaniak SwissTransfer - Android
+ * Copyright (C) 2024 Infomaniak Network SA
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.infomaniak.core2
+
+import android.content.Context
+import android.icu.text.DecimalFormat
+import android.icu.text.MeasureFormat
+import android.icu.text.MeasureFormat.FormatWidth
+import android.icu.text.NumberFormat
+import android.icu.util.Measure
+import android.icu.util.MeasureUnit
+import java.math.BigDecimal
+import java.util.Locale
+import kotlin.math.abs
+
+object FormatterFileSize {
+
+    private const val KIBI_BYTE = 1_024L
+    private const val KILO_BYTE = 1_000L
+
+    private const val FLAG_IEC_UNITS = 1 shl 3
+    private const val FLAG_SI_UNITS = 1 shl 2
+    private const val FLAG_SHORTER = 1 shl 0
+
+    fun Context.formatShortFileSize(bytes: Long, valueOnly: Boolean = false): String {
+        return formatFileSize(bytes, FLAG_IEC_UNITS or FLAG_SHORTER, valueOnly)
+    }
+
+    private fun Context.formatFileSize(bytes: Long, flags: Int, valueOnly: Boolean): String {
+
+        fun getSuffix(suffixes: MutableList<MeasureUnit>): MeasureUnit? {
+            return if (valueOnly) null else suffixes.removeFirstOrNull()
+        }
+
+        val suffixes = mutableListOf(
+            MeasureUnit.BYTE,
+            MeasureUnit.KILOBYTE,
+            MeasureUnit.MEGABYTE,
+            MeasureUnit.GIGABYTE,
+            MeasureUnit.TERABYTE,
+        )
+        val unit = if (flags and FLAG_IEC_UNITS != 0) KIBI_BYTE else KILO_BYTE
+        var multiplier = 1L
+
+        var result = abs(bytes).toFloat()
+        val suffixesCount = suffixes.count() - 1
+        var suffix = getSuffix(suffixes)
+
+        repeat(suffixesCount) {
+            if (result > 900) {
+                suffix = getSuffix(suffixes)
+                multiplier *= unit
+                result /= unit
+            }
+        }
+
+        val (roundFormat, roundedBytes) = when {
+            multiplier == 1L || result >= 100 -> "%.0f" to 0
+            result < 1 -> "%.2f" to 2
+            result < 10 -> if (flags and FLAG_SHORTER != 0) "%.1f" to 1 else "%.2f" to 2
+            else -> if (flags and FLAG_SHORTER != 0) "%.0f" to 0 else "%.2f" to 2 // 10 <= result < 100
+        }
+
+        result = abs(result)
+
+        val resultValue = String.format(roundFormat, result)
+        val resultValueFormatted = suffix?.let {
+            val locale = currentLocale()
+            formatMeasureShort(locale, getNumberFormatter(locale, roundedBytes), result, it)
+        }
+
+        return resultValueFormatted ?: resultValue
+    }
+
+    private fun Context.currentLocale(): Locale = resources.configuration.locales[0]
+
+    private fun getNumberFormatter(locale: Locale, fractionDigits: Int): NumberFormat {
+        return NumberFormat.getInstance(locale).apply {
+            minimumFractionDigits = fractionDigits
+            maximumFractionDigits = fractionDigits
+            isGroupingUsed = false
+            // We do this only for DecimalFormat, since in the general NumberFormat case,
+            // calling setRoundingMode may throw an exception.
+            if (this is DecimalFormat) setRoundingMode(BigDecimal.ROUND_HALF_UP)
+        }
+    }
+
+    private fun formatMeasureShort(locale: Locale, numberFormatter: NumberFormat, value: Float, units: MeasureUnit): String {
+        val measureFormatter = MeasureFormat.getInstance(locale, FormatWidth.SHORT, numberFormatter)
+        return measureFormatter.format(Measure(value, units))
+    }
+}