change implementation details

Firestore/Swift/Source/Helper/PipelineHelper.swift

@@ -25,26 +25,12 @@ enum Helper {
     }
   }
 
-  static func selectablesToMap(selectables: [Any]) -> [String: Expr] {
-    var result = [String: Expr]()
-    for selectable in selectables {
-      if let stringSelectable = selectable as? String {
-        result[stringSelectable] = Field(stringSelectable)
-      } else if let fieldSelectable = selectable as? Field {
-        result[fieldSelectable.alias] = fieldSelectable.expr
-      } else if let exprAliasSelectable = selectable as? ExprWithAlias {
-        result[exprAliasSelectable.alias] = exprAliasSelectable.expr
-      }
+  static func selectablesToMap(selectables: [Selectable]) -> [String: Expr] {
+    let exprMap = selectables.reduce(into: [String: Expr]()) { result, selectable in
+      let value = selectable as! SelectableWrapper
+      result[value.alias] = value.expr
     }
-    return result
-  }
-
-  static func vectorToExpr(_ value: VectorValue) -> Expr {
-    return Field("PLACEHOLDER")
-  }
-
-  static func timeUnitToExpr(_ value: TimeUnit) -> Expr {
-    return Field("PLACEHOLDER")
+    return exprMap
   }
 
   static func map(_ elements: [String: Sendable]) -> FunctionExpr {

Firestore/Swift/Source/BridgeWrapper.swift → Firestore/Swift/Source/PipelineWrapper.swift

@@ -19,3 +19,8 @@ protocol BridgeWrapper {
 protocol AggregateBridgeWrapper {
   var bridge: AggregateFunctionBridge { get }
 }
+
+protocol SelectableWrapper: Sendable {
+  var alias: String { get }
+  var expr: Expr { get }
+}

Firestore/Swift/Source/SwiftAPI/Pipeline/Aggregation/AggregateFunction.swift

@@ -23,7 +23,7 @@ public class AggregateFunction: AggregateBridgeWrapper, @unchecked Sendable {
     self.agrs = agrs
     bridge = AggregateFunctionBridge(
       name: functionName,
-      args: self.agrs.map { ($0 as! BridgeWrapper).bridge
+      args: self.agrs.map { $0.toBridge()
       }
     )
   }

Firestore/Swift/Source/SwiftAPI/Pipeline/Expr.swift

@@ -19,6 +19,7 @@
 #endif // SWIFT_PACKAGE
 import Foundation
 
+// TODO: the implementation of `Expr` is not complete
 public protocol Expr: Sendable {
   func `as`(_ name: String) -> ExprWithAlias
 
@@ -607,7 +608,7 @@ public extension Expr {
   }
 
   func cosineDistance(_ other: VectorValue) -> FunctionExpr {
-    return FunctionExpr("cosine_distance", [self, Helper.vectorToExpr(other)])
+    return FunctionExpr("cosine_distance", [self, Helper.sendableToExpr(other)])
   }
 
   func cosineDistance(_ other: [Double]) -> FunctionExpr {
@@ -619,7 +620,7 @@ public extension Expr {
   }
 
   func dotProduct(_ other: VectorValue) -> FunctionExpr {
-    return FunctionExpr("dot_product", [self, Helper.vectorToExpr(other)])
+    return FunctionExpr("dot_product", [self, Helper.sendableToExpr(other)])
   }
 
   func dotProduct(_ other: [Double]) -> FunctionExpr {
@@ -631,7 +632,7 @@ public extension Expr {
   }
 
   func euclideanDistance(_ other: VectorValue) -> FunctionExpr {
-    return FunctionExpr("euclidean_distance", [self, Helper.vectorToExpr(other)])
+    return FunctionExpr("euclidean_distance", [self, Helper.sendableToExpr(other)])
   }
 
   func euclideanDistance(_ other: [Double]) -> FunctionExpr {
@@ -643,7 +644,7 @@ public extension Expr {
   }
 
   func manhattanDistance(_ other: VectorValue) -> FunctionExpr {
-    return FunctionExpr("manhattan_distance", [self, Helper.vectorToExpr(other)])
+    return FunctionExpr("manhattan_distance", [self, Helper.sendableToExpr(other)])
   }
 
   func manhattanDistance(_ other: [Double]) -> FunctionExpr {
@@ -683,7 +684,7 @@ public extension Expr {
   func timestampAdd(_ unit: TimeUnit, _ amount: Int) -> FunctionExpr {
     return FunctionExpr(
       "timestamp_add",
-      [self, Helper.timeUnitToExpr(unit), Helper.sendableToExpr(amount)]
+      [self, Helper.sendableToExpr(unit), Helper.sendableToExpr(amount)]
     )
   }
 
@@ -694,7 +695,7 @@ public extension Expr {
   func timestampSub(_ unit: TimeUnit, _ amount: Int) -> FunctionExpr {
     return FunctionExpr(
       "timestamp_sub",
-      [self, Helper.timeUnitToExpr(unit), Helper.sendableToExpr(amount)]
+      [self, Helper.sendableToExpr(unit), Helper.sendableToExpr(amount)]
     )
   }
 
@@ -780,7 +781,7 @@ public extension Expr {
 }
 
 extension Expr {
-  func exprToExprBridge() -> ExprBridge {
+  func toBridge() -> ExprBridge {
     return (self as! BridgeWrapper).bridge
   }
 }

Firestore/Swift/Source/SwiftAPI/Pipeline/Expr/Constant.swift

@@ -26,8 +26,11 @@ public struct Constant: Expr, BridgeWrapper, @unchecked Sendable {
   // Initializer for optional values (including nil)
   init(_ value: Any?) {
     self.value = value
-    // TODO:
-    bridge = ConstantBridge(value)
+    if value == nil {
+      bridge = ConstantBridge(NSNull())
+    } else {
+      bridge = ConstantBridge(value!)
+    }
   }
 
   // Initializer for numbers

Firestore/Swift/Source/SwiftAPI/Pipeline/Expr/Field.swift

@@ -12,13 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-public class Field: ExprBridge, Expr, Selectable, BridgeWrapper, SelectableInternal,
+public class Field: ExprBridge, Expr, Selectable, BridgeWrapper, SelectableWrapper,
   @unchecked Sendable {
   var bridge: ExprBridge
 
   var alias: String
 
-  var expr: any Expr {
+  var expr: Expr {
     return self
   }
 

Firestore/Swift/Source/SwiftAPI/Pipeline/Expr/FunctionExpr.swift

@@ -23,7 +23,7 @@ public class FunctionExpr: Expr, BridgeWrapper, @unchecked Sendable {
     self.agrs = agrs
     bridge = FunctionExprBridge(
       name: functionName,
-      args: self.agrs.map { ($0 as! BridgeWrapper).bridge
+      args: self.agrs.map { $0.toBridge()
       }
     )
   }

Firestore/Swift/Source/SwiftAPI/Pipeline/Expr/FunctionExpr/BooleanExpr.swift

@@ -27,7 +27,6 @@ public class BooleanExpr: FunctionExpr, @unchecked Sendable {
     try BooleanExpr("or", [lhs, rhs()])
   }
 
-  // not
   public static prefix func ! (lhs: BooleanExpr) -> BooleanExpr {
     return BooleanExpr("not", [lhs])
   }

Firestore/Swift/Source/SwiftAPI/Pipeline/ExprWithAlias.swift

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-public struct ExprWithAlias: Selectable, SelectableInternal, Sendable {
+public struct ExprWithAlias: Selectable, SelectableWrapper, Sendable {
   public var alias: String
 
   public var expr: Expr

Firestore/Swift/Source/SwiftAPI/Pipeline/Ordering.swift

@@ -22,7 +22,7 @@ public class Ordering: @unchecked Sendable {
   init(expr: Expr, direction: Direction) {
     self.expr = expr
     self.direction = direction
-    bridge = OrderingBridge(expr: expr.exprToExprBridge(), direction: direction.rawValue)
+    bridge = OrderingBridge(expr: expr.toBridge(), direction: direction.rawValue)
   }
 }
 

Firestore/Swift/Source/SwiftAPI/Pipeline/Pipeline.swift

@@ -117,9 +117,9 @@ public struct Pipeline: @unchecked Sendable {
   /// - Parameter selections: `String` values representing field names.
   /// - Returns: A new `Pipeline` object with this stage appended to the stage list.
   public func select(_ selection: String, _ additionalSelections: String...) -> Pipeline {
-    let selections = [selection] + additionalSelections
+    let selections = ([selection] + additionalSelections).map { Field($0) }
     return Pipeline(
-      stages: stages + [Select(selections: selections + additionalSelections)],
+      stages: stages + [Select(selections: selections)],
       db: db
     )
   }
@@ -188,8 +188,8 @@ public struct Pipeline: @unchecked Sendable {
   /// - Parameter selections: The fields to include in the output documents, specified as
   ///  `String` values representing field names.
   public func distinct(_ group: String, _ additionalGroups: String...) -> Pipeline {
-    let groups = [group] + additionalGroups
-    return Pipeline(stages: stages + [Distinct(groups: groups + additionalGroups)], db: db)
+    let selections = ([group] + additionalGroups).map { Field($0) }
+    return Pipeline(stages: stages + [Distinct(groups: selections)], db: db)
   }
 
   /// Returns a set of distinct `Expr` values from the inputs to this stage.
@@ -276,7 +276,11 @@ public struct Pipeline: @unchecked Sendable {
   /// - Returns: A new `Pipeline` object with this stage appended.
   public func aggregate(_ accumulator: [AggregateWithAlias],
                         groups: [String]? = nil) -> Pipeline {
-    return Pipeline(stages: stages + [Aggregate(accumulators: accumulator, groups: groups)], db: db)
+    let selectables = groups?.map { Field($0) }
+    return Pipeline(
+      stages: stages + [Aggregate(accumulators: accumulator, groups: selectables)],
+      db: db
+    )
   }
 
   /// Performs a vector similarity search, ordering the result set by most similar to least

Firestore/Swift/Source/SwiftAPI/Pipeline/PipelineResult.swift

@@ -20,14 +20,14 @@
 import Foundation
 
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
-public struct PipelineResult<T>: @unchecked Sendable {
+public struct PipelineResult: @unchecked Sendable {
   let bridge: __PipelineResultBridge
 
   init(_ bridge: __PipelineResultBridge) {
     self.bridge = bridge
     ref = self.bridge.reference
     id = self.bridge.documentID
-    data = self.bridge.data() as! T
+    data = self.bridge.data()
     createTime = self.bridge.create_time
     updateTime = self.bridge.update_time
   }
@@ -45,12 +45,26 @@ public struct PipelineResult<T>: @unchecked Sendable {
   public let updateTime: Timestamp?
 
   /// Retrieves all fields in the result as a dictionary.
-  public let data: T
+  public let data: [String: Sendable]
 
   /// Retrieves the field specified by `fieldPath`.
   /// - Parameter fieldPath: The field path (e.g., "foo" or "foo.bar").
   /// - Returns: The data at the specified field location or `nil` if no such field exists.
-  public func get(_ fieldPath: Any) -> Sendable? {
+  public func get(_ fieldName: String) -> Sendable? {
+    return data[fieldName]
+  }
+
+  /// Retrieves the field specified by `fieldPath`.
+  /// - Parameter fieldPath: The field path (e.g., "foo" or "foo.bar").
+  /// - Returns: The data at the specified field location or `nil` if no such field exists.
+  public func get(_ fieldPath: FieldPath) -> Sendable? {
     return "PLACEHOLDER"
   }
+
+  /// Retrieves the field specified by `fieldPath`.
+  /// - Parameter fieldPath: The field path (e.g., "foo" or "foo.bar").
+  /// - Returns: The data at the specified field location or `nil` if no such field exists.
+  public func get(_ field: Field) -> Sendable? {
+    return data[field.fieldName]
+  }
 }

Firestore/Swift/Source/SwiftAPI/Pipeline/PipelineSnapshot.swift

@@ -25,7 +25,7 @@ public struct PipelineSnapshot: Sendable {
   public let pipeline: Pipeline
 
   /// An array of all the results in the `PipelineSnapshot`.
-  let results_cache: [PipelineResult<[String: Sendable]>]
+  let results_cache: [PipelineResult]
 
   /// The time at which the pipeline producing this result was executed.
   public let executionTime: Timestamp
@@ -39,16 +39,7 @@ public struct PipelineSnapshot: Sendable {
     results_cache = self.bridge.results.map { PipelineResult($0) }
   }
 
-  public func results() -> [PipelineResult<[String: Sendable]>] {
+  public func results() -> [PipelineResult] {
     return results_cache
   }
-
-  public func results<T: Decodable>(decodeAsType: T.Type = T.self,
-                                    decoder: Firestore
-                                      .Decoder = .init()) async throws -> [PipelineResult<
-    T
-  >] {
-    return try decoder
-      .decode(T.self, from: results, in: nil as DocumentReference?) as! [PipelineResult<T>]
-  }
 }

Firestore/Swift/Source/SwiftAPI/Pipeline/PipelineSource.swift

@@ -33,22 +33,23 @@ public struct PipelineSource: @unchecked Sendable {
   }
 
   public func database() -> Pipeline {
-    return Pipeline(stages: [CollectionSource(collection: "placeholder")], db: db)
+    return Pipeline(stages: [DatabaseSource()], db: db)
   }
 
   public func documents(_ docs: [DocumentReference]) -> Pipeline {
-    return Pipeline(stages: [CollectionSource(collection: "placeholder")], db: db)
+    let paths = docs.map { $0.path }
+    return Pipeline(stages: [DocumentsSource(paths: paths)], db: db)
   }
 
   public func documents(_ paths: [String]) -> Pipeline {
-    return Pipeline(stages: [CollectionSource(collection: "placeholder")], db: db)
+    return Pipeline(stages: [DocumentsSource(paths: paths)], db: db)
   }
 
   public func create(from query: Query) -> Pipeline {
-    return Pipeline(stages: [CollectionSource(collection: "placeholder")], db: db)
+    return Pipeline(stages: [QuerySource(query: query)], db: db)
   }
 
   public func create(from aggregateQuery: AggregateQuery) -> Pipeline {
-    return Pipeline(stages: [CollectionSource(collection: "placeholder")], db: db)
+    return Pipeline(stages: [AggregateQuerySource(aggregateQuery: aggregateQuery)], db: db)
   }
 }

Firestore/Swift/Source/SwiftAPI/Pipeline/TimeUnit.swift

@@ -34,12 +34,4 @@ public struct TimeUnit: Sendable, Equatable, Hashable {
   init(kind: Kind) {
     rawValue = kind.rawValue
   }
-
-  public init(rawValue: String) {
-    if let kind = Kind(rawValue: rawValue) {
-      self.rawValue = kind.rawValue
-    } else {
-      fatalError("Invalid TimeUnit: \(rawValue)")
-    }
-  }
 }