Add base Decode game logic classes (#22)

- add Artifact interface with PurpleArtifact and GreenArtifact
- add Motif for artifact collection patterns using AprilTag IDs 21-23
- add circular indexing for motif sequences
- add Obelisk to detect correct motif from AprilTag detections
- filter detections by alliance color and position
- add AllianceColor enum for RED and BLUE
- add extra motif methods
- lint decode/ directory

Author: MGross21

TeamCode/src/main/kotlin/pioneer/decode/Artifact.kt

@@ -0,0 +1,22 @@
+package pioneer.decode
+
+import org.firstinspires.ftc.vision.opencv.ColorRange
+import org.firstinspires.ftc.vision.opencv.PredominantColorProcessor
+
+interface Artifact {
+    val name: String
+    val color: ColorRange
+    val swatch: PredominantColorProcessor.Swatch
+}
+
+class PurpleArtifact : Artifact {
+    override val name: String = "Purple"
+    override val color: ColorRange = ColorRange.ARTIFACT_PURPLE
+    override val swatch: PredominantColorProcessor.Swatch = PredominantColorProcessor.Swatch.ARTIFACT_PURPLE
+}
+
+class GreenArtifact : Artifact {
+    override val name: String = "Green"
+    override val color: ColorRange = ColorRange.ARTIFACT_GREEN
+    override val swatch: PredominantColorProcessor.Swatch = PredominantColorProcessor.Swatch.ARTIFACT_GREEN
+}

TeamCode/src/main/kotlin/pioneer/decode/Motif.kt

@@ -0,0 +1,52 @@
+package pioneer.decode
+
+class Motif(
+    val aprilTagId: Int,
+) {
+    private val artifacts: List<Artifact>?
+    private var currentIndex: Int = 0
+
+    init {
+        artifacts =
+            when (aprilTagId) {
+                21 -> listOf(GreenArtifact(), PurpleArtifact(), PurpleArtifact())
+                22 -> listOf(PurpleArtifact(), GreenArtifact(), PurpleArtifact())
+                23 -> listOf(PurpleArtifact(), PurpleArtifact(), GreenArtifact())
+                else -> null
+            }
+    }
+
+    // Returns the next artifact in the motif's sequence, cycling back to the start if needed
+    fun getNextArtifact(): Artifact? {
+        if (artifacts == null || artifacts.isEmpty()) return null
+
+        val artifact = artifacts[currentIndex]
+        currentIndex = (currentIndex + 1) % artifacts.size
+        return artifact
+    }
+
+    // Returns the current artifact without advancing the index
+    fun currentArtifact(): Artifact? {
+        if (artifacts == null || artifacts.isEmpty()) return null
+        return artifacts[currentIndex]
+    }
+
+    // Returns the artifact at a specific position in the pattern (0-indexed)
+    fun getArtifactAt(index: Int): Artifact? {
+        if (artifacts == null || artifacts.isEmpty() || index < 0 || index >= artifacts.size) return null
+        return artifacts[index]
+    }
+
+    // Returns the current position in the pattern (0-indexed)
+    fun getCurrentIndex(): Int = currentIndex
+
+    // Returns true if this is a valid motif with artifacts
+    fun isValid(): Boolean = artifacts != null && artifacts.isNotEmpty()
+
+    // Returns the complete artifact sequence for this motif
+    fun getPattern(): List<Artifact>? = artifacts?.toList()
+
+    fun reset() {
+        currentIndex = 0
+    }
+}

TeamCode/src/main/kotlin/pioneer/decode/Obelisk.kt

@@ -0,0 +1,31 @@
+package pioneer.decode
+
+import org.firstinspires.ftc.vision.apriltag.AprilTagDetection
+import pioneer.general.AllianceColor
+
+class Obelisk {
+    companion object {
+        private val validMotifTagIds = setOf(21, 22, 23)
+
+        fun isValidMotifTag(aprilTagId: Int): Boolean = aprilTagId in validMotifTagIds
+
+        /**
+         * Filters the AprilTag detections to find the correct motif tag based on alliance color.
+         * If Blue alliance, look for right most valid tag (largest x in ftcPose)
+         * If Red alliance, look for left most valid tag (smallest x in ftcPose)
+         * Will work on close or far starting positions
+         */
+        fun detectMotif(
+            detections: List<AprilTagDetection>,
+            alliance: AllianceColor,
+        ): Motif? {
+            val validTags = detections.filter { it.ftcPose != null && isValidMotifTag(it.id) }
+            val motifTagId =
+                when (alliance) {
+                    AllianceColor.BLUE -> validTags.maxByOrNull { it.ftcPose.x }?.id
+                    AllianceColor.RED -> validTags.minByOrNull { it.ftcPose.x }?.id
+                }
+            return motifTagId?.let { Motif(it) }
+        }
+    }
+}

TeamCode/src/main/kotlin/pioneer/general/AllianceColor.kt

@@ -0,0 +1,6 @@
+package pioneer.general
+
+enum class AllianceColor {
+    RED,
+    BLUE
+}