Feature/search leaf nodes

app/src/main/java/com/orgzly/android/data/DataRepository.kt

@@ -9,6 +9,7 @@ import android.net.Uri
 import android.os.Handler
 import android.text.TextUtils
 import androidx.lifecycle.LiveData
+import androidx.lifecycle.MediatorLiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.Transformations
 import androidx.localbroadcastmanager.content.LocalBroadcastManager
@@ -1159,6 +1160,32 @@ class DataRepository @Inject constructor(
 
         val sqlQuery = buildSqlQuery(query)
 
+        if (query.options.searchLeafNodes) { // If search contained "h.leaf" in it,
+            // display only leaf nodes of the live data query
+            val result = MediatorLiveData<List<NoteView>>()
+            val parentNotesLiveData = db.noteView().runQueryLiveData(sqlQuery)
+
+            result.addSource(parentNotesLiveData) { parentNotes ->
+                if (parentNotes.isNotEmpty()) {
+                    var parentIds = parentNotes.map { it.note.id }
+
+                    val leafNotesLiveData = db.noteView().runQueryLeafNotesData(parentIds) // This is a recursive
+                    // CTE (Common Table Expression) that searches all the child nodes of the parent ids,
+                    // the returning result filters out the notes with ids that have children in the same selection
+
+                    result.removeSource(parentNotesLiveData)
+
+                    result.addSource(leafNotesLiveData) { leafNotes ->
+                        result.value = leafNotes
+                    }
+                } else {
+                    result.value = emptyList()
+                }
+            }
+
+            return  result
+        }
+
         return db.noteView().runQueryLiveData(sqlQuery)
     }
 

app/src/main/java/com/orgzly/android/db/dao/NoteViewDao.kt

@@ -26,6 +26,28 @@ abstract class NoteViewDao {
     """)
     abstract fun getVisibleLiveData(bookId: Long): LiveData<List<NoteView>>
 
+    @Query("""
+        WITH RECURSIVE temp_notes AS (
+            $QUERY
+            GROUP BY notes.id, event_timestamp
+        ), 
+        rec_search_leaf_notes AS (
+            select * from temp_notes 
+            WHERE temp_notes.id IN (:noteIdList)
+            UNION ALL
+            SELECT 
+                a.*
+            FROM temp_notes a
+            JOIN rec_search_leaf_notes b ON b.id = a.parent_id
+        )
+        SELECT DISTINCT b.* 
+        FROM rec_search_leaf_notes b
+        WHERE b.id NOT IN (
+            SELECT parent_id FROM rec_search_leaf_notes WHERE parent_id IS NOT NULL
+        )
+    """)
+    abstract fun runQueryLeafNotesData(noteIdList: List<Long>): LiveData<List<NoteView>>
+
     @Query("""
         $QUERY
         WHERE notes.book_id = :bookId

app/src/main/java/com/orgzly/android/query/HierarchyType.kt

@@ -0,0 +1,3 @@
+package com.orgzly.android.query
+
+enum class HierarchyType { LEAF }

app/src/main/java/com/orgzly/android/query/Options.kt

@@ -1,3 +1,6 @@
 package com.orgzly.android.query
 
-data class Options(val agendaDays: Int = 0)
+data class Options(
+    val agendaDays: Int = 0,
+    val searchLeafNodes: Boolean = false
+)

app/src/main/java/com/orgzly/android/query/user/DottedQueryParser.kt

@@ -113,6 +113,10 @@ open class DottedQueryParser : QueryParser() {
             OptionMatch("""^ad\.(\d+)$""") { match, options ->
                 val days = match.groupValues[1].toInt()
                 if (days > 0) options.copy(agendaDays = days) else null
+            },
+            OptionMatch("""^(\.)?h\.(.+)""") { match, options ->
+                if (match.groupValues[2].lowercase() == HierarchyType.LEAF.toString().lowercase())
+                    options.copy(searchLeafNodes = true) else null
             }
     )
 }