docs: Document classes in the data layer

app/src/main/java/org/nsh07/pomodoro/data/Preference.kt

@@ -1,8 +1,18 @@
+/*
+ * Copyright (c) 2025 Nishant Mishra
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
 package org.nsh07.pomodoro.data
 
 import androidx.room.Entity
 import androidx.room.PrimaryKey
 
+/**
+ * Class for storing app preferences (settings) in the app's database
+ */
 @Entity(tableName = "int_preference")
 data class IntPreference(
     @PrimaryKey

app/src/main/java/org/nsh07/pomodoro/data/PreferenceRepository.kt

@@ -1,17 +1,42 @@
+/*
+ * Copyright (c) 2025 Nishant Mishra
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
 package org.nsh07.pomodoro.data
 
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 
+/**
+ * Interface for reading/writing app preferences to the app's database. This style of storage aims
+ * to mimic the Preferences DataStore library, preventing the requirement of migration if the
+ * database schema changes.
+ */
 interface PreferenceRepository {
+    /**
+     * Saves an integer preference key-value pair to the database.
+     */
     suspend fun saveIntPreference(key: String, value: Int): Int
 
+    /**
+     * Retrieves an integer preference key-value pair from the database.
+     */
     suspend fun getIntPreference(key: String): Int?
 
+    /**
+     * Erases all integer preference key-value pairs in the database. Do note that the default values
+     * will need to be rewritten manually
+     */
     suspend fun resetSettings()
 }
 
+/**
+ * See [PreferenceRepository] for more details
+ */
 class AppPreferenceRepository(
     private val preferenceDao: PreferenceDao,
     private val ioDispatcher: CoroutineDispatcher = Dispatchers.IO

app/src/main/java/org/nsh07/pomodoro/data/Stat.kt

@@ -10,6 +10,11 @@ package org.nsh07.pomodoro.data
 import androidx.room.Entity
 import androidx.room.PrimaryKey
 
+/**
+ * Data class for storing the user's statistics in the app's database. This class stores the focus
+ * durations for the 4 quarters of a day (00:00 - 12:00, 12:00 - 16:00, 16:00 - 20:00, 20:00 - 00:00)
+ * separately for later analysis (e.g. for showing which parts of the day are most productive).
+ */
 @Entity(tableName = "stat")
 data class Stat(
     @PrimaryKey
@@ -20,3 +25,16 @@ data class Stat(
     val focusTimeQ4: Long,
     val breakTime: Long
 )
+
+data class StatSummary(
+    val date: String,
+    val focusTime: Long,
+    val breakTime: Long
+)
+
+data class StatFocusTime(
+    val focusTimeQ1: Long,
+    val focusTimeQ2: Long,
+    val focusTimeQ3: Long,
+    val focusTimeQ4: Long
+)

app/src/main/java/org/nsh07/pomodoro/data/StatDao.kt

@@ -36,8 +36,11 @@ interface StatDao {
     @Query("SELECT * FROM stat WHERE date = :date")
     fun getStat(date: String): Flow<Stat?>
 
-    @Query("SELECT * FROM stat")
-    fun getStats(): Flow<List<Stat>>
+    @Query("SELECT date, focusTimeQ1 + focusTimeQ2 + focusTimeQ3 + focusTimeQ4 as focusTime, breakTime FROM stat")
+    fun getAllStatsSummary(): Flow<List<StatSummary>>
+
+    @Query("SELECT AVG(focusTimeQ1), AVG(focusTimeQ2), AVG(focusTimeQ3), AVG(focusTimeQ4) FROM stat")
+    fun getAvgFocusTimes(): Flow<StatFocusTime?>
 
     @Query("SELECT EXISTS (SELECT * FROM stat WHERE date = :date)")
     suspend fun statExists(date: String): Boolean

app/src/main/java/org/nsh07/pomodoro/data/StatRepository.kt

@@ -14,6 +14,11 @@ import kotlinx.coroutines.withContext
 import java.time.LocalDate
 import java.time.LocalTime
 
+/**
+ * Interface for reading/writing statistics to the app's database. Ideally, writing should be done
+ * through the timer screen's ViewModel and reading should be done through the stats screen's
+ * ViewModel
+ */
 interface StatRepository {
     suspend fun addFocusTime(focusTime: Long)
 
@@ -21,9 +26,14 @@ interface StatRepository {
 
     fun getTodayStat(): Flow<Stat?>
 
-    fun getAllStats(): Flow<List<Stat>>
+    fun getAllStatsSummary(): Flow<List<StatSummary>>
+
+    fun getAverageFocusTimes(): Flow<StatFocusTime?>
 }
 
+/**
+ * See [StatRepository] for more details
+ */
 class AppStatRepository(
     private val statDao: StatDao,
     private val ioDispatcher: CoroutineDispatcher = Dispatchers.IO
@@ -85,5 +95,7 @@ class AppStatRepository(
         return statDao.getStat(currentDate)
     }
 
-    override fun getAllStats(): Flow<List<Stat>> = statDao.getStats()
+    override fun getAllStatsSummary(): Flow<List<StatSummary>> = statDao.getAllStatsSummary()
+
+    override fun getAverageFocusTimes(): Flow<StatFocusTime?> = statDao.getAvgFocusTimes()
 }

app/src/main/java/org/nsh07/pomodoro/data/TimerRepository.kt

@@ -7,6 +7,10 @@
 
 package org.nsh07.pomodoro.data
 
+/**
+ * Interface that holds the timer durations for each timer type. This repository maintains a single
+ * source of truth for the timer durations for the various ViewModels in the app.
+ */
 interface TimerRepository {
     var focusTime: Long
     var shortBreakTime: Long
@@ -14,6 +18,9 @@ interface TimerRepository {
     var sessionLength: Int
 }
 
+/**
+ * See [TimerRepository] for more details
+ */
 class AppTimerRepository : TimerRepository {
     override var focusTime = 25 * 60 * 1000L
     override var shortBreakTime = 5 * 60 * 1000L