Add sort and type-safe filters

Author: gpunto

stream-android-core/src/main/java/io/getstream/android/core/api/filter/Filter.kt

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2014-2025 Stream.io Inc. All rights reserved.
+ *
+ * Licensed under the Stream License;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    https://github.com/GetStream/stream-core-android/blob/main/LICENSE
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.getstream.android.core.api.filter
+
+import io.getstream.android.core.annotations.StreamInternalApi
+import io.getstream.android.core.annotations.StreamPublishedApi
+import io.getstream.android.core.internal.filter.FilterOperator
+
+/**
+ * Base interface for filters used in Stream API operations.
+ *
+ * Filters are used to specify criteria for querying and retrieving data from Stream services. Each
+ * filter implementation defines specific matching logic for different comparison operations.
+ */
+@StreamPublishedApi
+public sealed interface Filter<F : FilterField>
+
+internal data class BinaryOperationFilter<F : FilterField, V : Any>(
+    val operator: FilterOperator,
+    val field: F,
+    val value: V,
+) : Filter<F>
+
+internal data class CollectionOperationFilter<F : FilterField>(
+    internal val operator: FilterOperator,
+    val filters: Set<Filter<F>>,
+) : Filter<F>
+
+/** Converts a [Filter] instance to a request map suitable for API queries. */
+@StreamInternalApi
+public fun Filter<*>.toRequest(): Map<String, Any> =
+    when (this) {
+        is BinaryOperationFilter<*, *> -> mapOf(field.remote to mapOf(operator.remote to value))
+        is CollectionOperationFilter<*> ->
+            mapOf(operator.remote to filters.map(Filter<*>::toRequest))
+    }

stream-android-core/src/main/java/io/getstream/android/core/api/filter/FilterField.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2014-2025 Stream.io Inc. All rights reserved.
+ *
+ * Licensed under the Stream License;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    https://github.com/GetStream/stream-core-android/blob/main/LICENSE
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.getstream.android.core.api.filter
+
+/**
+ * Interface representing a field that can be used in filters for querying data from the Stream API.
+ *
+ * Implementations of this interface should provide [remote], which is the name of the field as
+ * expected by the Stream API.
+ */
+public interface FilterField {
+    /** The name of this field as expected by the Stream API. */
+    public val remote: String
+}

stream-android-core/src/main/java/io/getstream/android/core/api/filter/Filters.kt

@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2014-2025 Stream.io Inc. All rights reserved.
+ *
+ * Licensed under the Stream License;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    https://github.com/GetStream/stream-core-android/blob/main/LICENSE
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.getstream.android.core.api.filter
+
+import io.getstream.android.core.internal.filter.FilterOperator
+
+/** Utility class for building filters. */
+public object Filters {
+    /**
+     * Creates a filter that combines multiple filters with a logical AND operation.
+     *
+     * @param filters The filters to combine.
+     * @return A filter that matches when all provided filters match.
+     */
+    public fun <F : FilterField> and(vararg filters: Filter<F>): Filter<F> =
+        CollectionOperationFilter(FilterOperator.AND, filters.toSet())
+
+    /**
+     * Creates a filter that combines multiple filters with a logical OR operation.
+     *
+     * @param filters The filters to combine.
+     * @return A filter that matches when any of the specified filters match.
+     */
+    public fun <F : FilterField> or(vararg filters: Filter<F>): Filter<F> =
+        CollectionOperationFilter(FilterOperator.OR, filters.toSet())
+}
+
+/**
+ * Creates a filter that checks if this field equals a specific value.
+ *
+ * @param value The value to check equality against.
+ * @return A filter that matches when this field equals the specified value.
+ */
+public fun <F : FilterField> F.equal(value: Any): Filter<F> =
+    BinaryOperationFilter(FilterOperator.EQUAL, this, value)
+
+/**
+ * Creates a filter that checks if this field is greater than a specific value.
+ *
+ * @param value The value to check against.
+ * @return A filter that matches when this field is greater than the specified value.
+ */
+public fun <F : FilterField> F.greater(value: Any): Filter<F> =
+    BinaryOperationFilter(FilterOperator.GREATER, this, value)
+
+/**
+ * Creates a filter that checks if this field is greater than or equal to a specific value.
+ *
+ * @param value The value to check against.
+ * @return A filter that matches when this field is greater than or equal to the specified value.
+ */
+public fun <F : FilterField> F.greaterOrEqual(value: Any): Filter<F> =
+    BinaryOperationFilter(FilterOperator.GREATER_OR_EQUAL, this, value)
+
+/**
+ * Creates a filter that checks if this field is less than a specific value.
+ *
+ * @param value The value to check against.
+ * @return A filter that matches when this field is less than the specified value.
+ */
+public fun <F : FilterField> F.less(value: Any): Filter<F> =
+    BinaryOperationFilter(FilterOperator.LESS, this, value)
+
+/**
+ * Creates a filter that checks if this field is less than or equal to a specific value.
+ *
+ * @param value The value to check against.
+ * @return A filter that matches when this field is less than or equal to the specified value.
+ */
+public fun <F : FilterField> F.lessOrEqual(value: Any): Filter<F> =
+    BinaryOperationFilter(FilterOperator.LESS_OR_EQUAL, this, value)
+
+/**
+ * Creates a filter that checks if this field's value is in a specific list of values.
+ *
+ * @param values The list of values to check against.
+ * @return A filter that matches when this field's value is in the specified list.
+ */
+public fun <F : FilterField> F.`in`(values: List<Any>): Filter<F> =
+    BinaryOperationFilter(FilterOperator.IN, this, values.toSet())
+
+/**
+ * Creates a filter that checks if this field's value is in a specific set of values.
+ *
+ * @param values The values to check against.
+ * @return A filter that matches when this field's value is in the specified values.
+ */
+public fun <F : FilterField> F.`in`(vararg values: Any): Filter<F> =
+    BinaryOperationFilter(FilterOperator.IN, this, values.toSet())
+
+/**
+ * Creates a filter that performs a full-text query on this field.
+ *
+ * @param value The query string to search for.
+ * @return A filter that matches based on the full-text query.
+ */
+public fun <F : FilterField> F.query(value: String): Filter<F> =
+    BinaryOperationFilter(FilterOperator.QUERY, this, value)
+
+/**
+ * Creates a filter that performs autocomplete matching on this field.
+ *
+ * @param value The string to autocomplete against.
+ * @return A filter that matches based on autocomplete functionality.
+ */
+public fun <F : FilterField> F.autocomplete(value: String): Filter<F> =
+    BinaryOperationFilter(FilterOperator.AUTOCOMPLETE, this, value)
+
+/**
+ * Creates a filter that checks if this field exists.
+ *
+ * @return A filter that matches when this field exists.
+ */
+public fun <F : FilterField> F.exists(): Filter<F> =
+    BinaryOperationFilter(FilterOperator.EXISTS, this, true)
+
+/**
+ * Creates a filter that checks if this field does not exist.
+ *
+ * @return A filter that matches when this field does not exist.
+ */
+public fun <F : FilterField> F.doesNotExist(): Filter<F> =
+    BinaryOperationFilter(FilterOperator.EXISTS, this, false)
+
+/**
+ * Creates a filter that checks if this field contains a specific value.
+ *
+ * @param value The value to check for within this field.
+ * @return A filter that matches when this field contains the specified value.
+ */
+public fun <F : FilterField> F.contains(value: Any): Filter<F> =
+    BinaryOperationFilter(FilterOperator.CONTAINS, this, value)
+
+/**
+ * Creates a filter that checks if a specific path exists within this field.
+ *
+ * @param value The path to check for existence.
+ * @return A filter that matches when the specified path exists in this field.
+ */
+public fun <F : FilterField> F.pathExists(value: String): Filter<F> =
+    BinaryOperationFilter(FilterOperator.PATH_EXISTS, this, value)

stream-android-core/src/main/java/io/getstream/android/core/api/filter/Sort.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2014-2025 Stream.io Inc. All rights reserved.
+ *
+ * Licensed under the Stream License;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    https://github.com/GetStream/stream-core-android/blob/main/LICENSE
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.getstream.android.core.api.filter
+
+/**
+ * A sort configuration that combines a sort field with a direction.
+ *
+ * This class represents a complete sort specification that can be applied to collections of the
+ * associated model type. It provides both local sorting capabilities and the ability to generate
+ * remote API request parameters.
+ */
+public open class Sort<T>(public val field: SortField<T>, public val direction: SortDirection) :
+    Comparator<T> {
+
+    /** Converts this sort configuration to a DTO map for API requests. */
+    public fun toDto(): Map<String, Any> =
+        mapOf("field" to field.remote, "direction" to direction.value)
+
+    override fun compare(o1: T?, o2: T?): Int {
+        return field.comparator.compare(o1, o2, direction)
+    }
+}

stream-android-core/src/main/java/io/getstream/android/core/api/filter/SortComparator.kt

@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2014-2025 Stream.io Inc. All rights reserved.
+ *
+ * Licensed under the Stream License;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    https://github.com/GetStream/stream-core-android/blob/main/LICENSE
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.getstream.android.core.api.filter
+
+import io.getstream.android.core.annotations.StreamInternalApi
+
+/**
+ * A comparator that can sort model instances by extracting comparable values.
+ *
+ * This class provides the foundation for local sorting operations by wrapping a lambda that
+ * extracts comparable values from model instances. It handles the comparison logic and direction
+ * handling internally.
+ *
+ * @param T The type of the model instances to be compared.
+ * @param V The type of the comparable value extracted from the model instances.
+ * @property value A lambda that extracts a comparable value from a model instance.
+ */
+public class SortComparator<T, V : Comparable<V>>(public val value: (T) -> V) {
+
+    /**
+     * Compares two model instances using the extracted values and sort direction.
+     *
+     * @param lhs The first model instance to compare
+     * @param rhs The second model instance to compare
+     * @param direction The direction of the sort
+     * @return A comparison result indicating the relative ordering
+     */
+    public fun compare(lhs: T?, rhs: T?, direction: SortDirection): Int {
+        val value1 = lhs?.let(value)
+        val value2 = rhs?.let(value)
+
+        return when {
+            value1 == null && value2 == null -> 0
+            value1 == null -> -direction.value
+            value2 == null -> direction.value
+            else -> value1.compareTo(value2) * direction.value
+        }
+    }
+
+    /**
+     * Converts this comparator to a type-erased version.
+     *
+     * @return An AnySortComparator that wraps this comparator
+     */
+    public fun toAny(): AnySortComparator<T> {
+        return AnySortComparator(this)
+    }
+}
+
+/**
+ * A type-erased wrapper for sort comparators that can work with any model type.
+ *
+ * This class provides a way to store and use sort comparators without knowing their specific
+ * generic type parameters. It's useful for creating collections of different sort configurations
+ * that can all work with the same model type.
+ *
+ * Type erased type avoids making SortField generic while keeping the underlying value type intact
+ * (no runtime type checks while sorting).
+ */
+public class AnySortComparator<T>(private val compare: (T?, T?, SortDirection) -> Int) {
+
+    /**
+     * Creates a type-erased comparator from a specific comparator instance.
+     *
+     * @param sort The specific comparator to wrap
+     */
+    public constructor(sort: SortComparator<T, *>) : this(sort::compare)
+
+    /**
+     * Compares two model instances using the wrapped comparator.
+     *
+     * @param lhs The left-hand side model instance
+     * @param rhs The right-hand side model instance
+     * @param direction The direction of the sort
+     * @return A comparison result indicating the relative ordering
+     */
+    public fun compare(lhs: T?, rhs: T?, direction: SortDirection): Int {
+        return this.compare.invoke(lhs, rhs, direction)
+    }
+}
+
+/**
+ * Extension function to sort a list of models using a list of sort configurations.
+ *
+ * @param T The type of elements in the list.
+ * @param sort A list of sort configurations to apply to the list.
+ */
+@StreamInternalApi
+public fun <T> List<T>.sortedWith(sort: List<Sort<T>>): List<T> =
+    sortedWith(CompositeComparator(sort))
+
+/**
+ * A composite comparator that combines multiple sort comparators. This class allows for sorting
+ * based on multiple criteria, where each comparator is applied in sequence.
+ *
+ * This implementation mirrors the Swift Array.sorted(using:) extension behavior:
+ * - Iterates through each sort comparator in order
+ * - Returns the first non-equal comparison result
+ * - If all comparators return equal (0), returns 0 to maintain stable sort order
+ *
+ * @param T The type of elements to be compared.
+ * @param comparators The list of comparators to be combined.
+ */
+@StreamInternalApi
+public class CompositeComparator<T>(private val comparators: List<Comparator<T>>) : Comparator<T> {
+
+    override fun compare(o1: T, o2: T): Int {
+        for (comparator in comparators) {
+            val result = comparator.compare(o1, o2)
+            when (result) {
+                0 -> continue // Equal, move to the next comparator
+                else -> return result // Return the first non-equal comparison result
+            }
+        }
+        return 0 // All comparators returned equal, maintain original order
+    }
+}