telemetry(amazonq): Add metrics utility to instrument generated patch…

…es applied to existing code.

plugins/amazonq/chat/jetbrains-community/src/software/aws/toolkits/jetbrains/services/amazonqFeatureDev/util/DiffMetrics.kt

@@ -0,0 +1,73 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.jetbrains.services.amazonqFeatureDev.util
+
+import com.intellij.diff.comparison.ComparisonManager
+import com.intellij.diff.comparison.ComparisonPolicy
+import com.intellij.diff.fragments.LineFragment
+import com.intellij.openapi.progress.EmptyProgressIndicator
+
+data class DiffMetrics(
+    val insertedLines: Int,
+    val insertedCharacters: Int
+)
+
+fun lineEnding(content: String, curr: Int, end: Int): Int {
+    require (curr <= end) { "curr must be within end of range" }
+    require (end <= content.length) { "end must be within content" }
+
+    return if (curr == end) {
+        -1
+    } else if (content[curr] == '\r') {
+        if ((curr + 1 < end) && (content[curr + 1] == '\n')) {
+            2
+        } else {
+            1
+        }
+    } else if (content[curr] == '\n') {
+        1
+    } else {
+        -1
+    }
+}
+
+fun getDiffMetrics(before: String, after: String): DiffMetrics {
+    val comparisonManager = ComparisonManager.getInstance()
+    val fragments = comparisonManager.compareLines(
+        before,
+        after,
+        ComparisonPolicy.DEFAULT,
+        EmptyProgressIndicator()
+    )
+
+    var accLineCount = 0
+    var accCharCount = 0
+
+    fragments.forEach { fragment: LineFragment ->
+        var curr = fragment.startOffset2
+        val end = fragment.endOffset2
+
+        while (curr < end) {
+            accLineCount += 1
+
+            // Consume leading whitespace:
+            while (curr < end && lineEnding(after, curr, end) == -1 && after[curr].isWhitespace()) curr++
+
+            // Consume through EOL:
+            val lineContentStart = curr
+            while (curr < end && lineEnding(after, curr, end) == -1) curr++
+            var lineContentEnd = curr
+            curr += maxOf(lineEnding(after, curr, end), 0)
+
+            // Walk back trailing whitespace and record character count before continuing to next line:
+            while (lineContentEnd > lineContentStart && after[lineContentEnd - 1].isWhitespace()) lineContentEnd--
+            accCharCount += lineContentEnd - lineContentStart
+        }
+    }
+
+    return DiffMetrics(
+        insertedLines = accLineCount,
+        insertedCharacters = accCharCount,
+    )
+}

plugins/amazonq/chat/jetbrains-community/tst/software/aws/toolkits/jetbrains/services/amazonqFeatureDev/util/DiffMetricsTest.kt

@@ -0,0 +1,128 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.jetbrains.services.amazonqFeatureDev.util
+
+import com.intellij.testFramework.LightPlatformTestCase
+import com.intellij.testFramework.TestApplicationManager
+import kotlin.test.assertNotEquals
+
+class DiffMetricsTest : LightPlatformTestCase() {
+    override fun setUp() {
+        super.setUp()
+        TestApplicationManager.getInstance()
+    }
+
+    fun `test empty input`() {
+        val metrics = getDiffMetrics("", "")
+        assertEquals(0, metrics.insertedLines)
+        assertEquals(0, metrics.insertedCharacters)
+    }
+
+    fun `test insertions are counted`() {
+        val before = """
+            line1
+            line2
+        """.trimIndent()
+
+        val after = """
+            line1
+            inserted
+            line2
+        """.trimIndent()
+
+        val metrics = getDiffMetrics(before, after)
+        assertEquals(1, metrics.insertedLines)
+        assertEquals(8, metrics.insertedCharacters)
+    }
+
+    fun `test modifications are counted`() {
+        val before = """
+            line1
+            line2
+            line3
+        """.trimIndent()
+
+        val after = """
+            line1
+            modified
+            line3
+        """.trimIndent()
+
+        val metrics = getDiffMetrics(before, after)
+        assertEquals(1, metrics.insertedLines)
+        assertEquals(8, metrics.insertedCharacters)
+    }
+
+    fun `test deletions are counted`() {
+        val before = """
+            line1
+            line2
+            line3
+        """.trimIndent()
+
+        val after = """
+            line1
+            line3
+        """.trimIndent()
+
+        val metrics = getDiffMetrics(before, after)
+        assertEquals(0, metrics.insertedLines)
+        assertEquals(0, metrics.insertedCharacters)
+    }
+
+    fun `test multiline and multiple hunks are counted`() {
+        val before = """
+            line1
+            line2
+            line3
+        """.trimIndent()
+
+        val after = """
+            inserted1
+            line1
+            inserted2
+            inserted3
+            line3
+            inserted4
+        """.trimIndent()
+
+        val metrics = getDiffMetrics(before, after)
+        assertEquals(4, metrics.insertedLines)
+        assertEquals(36, metrics.insertedCharacters)
+    }
+
+    fun  `test empty lines are counted`() {
+        val before = "line1"
+        val after = "line1\n\nline2"
+        val metrics = getDiffMetrics(before, after)
+        assertEquals(2, metrics.insertedLines)
+        assertEquals(5, metrics.insertedCharacters)
+    }
+
+    fun  `test trailing newline is not counted`() {
+        val before = "line1"
+        val after = "line1\nline2\n"
+        val metrics = getDiffMetrics(before, after)
+        assertEquals(1, metrics.insertedLines)
+        assertEquals(5, metrics.insertedCharacters)
+    }
+
+    fun  `test newline sequences are counted`() {
+        val before = "line1"
+        val after = "line1\nline2\rline3\r\nline4"
+        val metrics = getDiffMetrics(before, after)
+        assertEquals(3, metrics.insertedLines)
+        assertEquals(15, metrics.insertedCharacters)
+    }
+
+    fun `test leading and trailing whitespace are not counted as characters`() {
+        val before = "line1\nline2"
+        val after = "line1\n    line2"
+
+        val metrics = getDiffMetrics(before, after)
+        assertEquals(1, metrics.insertedLines)
+        assertEquals(5, metrics.insertedCharacters)
+        assertNotEquals(9, metrics.insertedCharacters)
+    }
+}