Add LangChainChatModel and ReadablePythonError

Author: intitni

Tool/Sources/LangChain/LangChainChatModel.swift

@@ -0,0 +1,43 @@
+import Foundation
+import Preferences
+import PythonKit
+
+public enum LangChainChatModel {
+    public static func DynamicChatOpenAI(
+        temperature: Double
+    ) throws -> PythonObject {
+        switch UserDefaults.shared.value(for: \.chatFeatureProvider) {
+        case .openAI:
+            let model = UserDefaults.shared.value(for: \.chatGPTModel)
+            let apiBaseURL = UserDefaults.shared.value(for: \.openAIBaseURL)
+            let apiKey = UserDefaults.shared.value(for: \.openAIAPIKey)
+            return try withReadableThrowingPython {
+                let chatModels = try Python.attemptImport("langchain.chat_models")
+                let ChatOpenAI = chatModels.ChatOpenAI
+                return ChatOpenAI(
+                    temperature: temperature,
+                    model: model,
+                    openai_api_base: "\(apiBaseURL)/v1",
+                    openai_api_key: apiKey
+                )
+            }
+        case .azureOpenAI:
+            let apiBaseURL = UserDefaults.shared.value(for: \.azureOpenAIBaseURL)
+            let apiKey = UserDefaults.shared.value(for: \.azureOpenAIAPIKey)
+            let deployment = UserDefaults.shared.value(for: \.azureChatGPTDeployment)
+            return try withReadableThrowingPython {
+                let chatModels = try Python.attemptImport("langchain.chat_models")
+                let ChatOpenAI = chatModels.AzureChatOpenAI
+                return ChatOpenAI(
+                    temperature: temperature,
+                    openai_api_type: "azure",
+                    openai_api_version: "2023-03-15-preview",
+                    deployment_name: deployment,
+                    openai_api_base: apiBaseURL,
+                    openai_api_key: apiKey
+                )
+            }
+        }
+    }
+}
+

Tool/Sources/LangChain/ReadablePythonError.swift

@@ -0,0 +1,34 @@
+import Foundation
+import PythonKit
+
+public struct ReadablePythonError: Error, LocalizedError {
+    public var error: PythonError
+
+    public init(_ error: PythonError) {
+        self.error = error
+    }
+
+    public var errorDescription: String? {
+        switch error {
+        case let .exception(object, _):
+            return "\(object)"
+        case let .invalidCall(object):
+            return "Invalid call: \(object)"
+        case let .invalidModule(module):
+            return "Invalid module: \(module)"
+        }
+    }
+}
+
+public func withReadableThrowingPython<T>(
+    _ closure: () throws -> T
+) throws -> T {
+    do {
+        return try closure()
+    } catch let error as PythonError {
+        throw ReadablePythonError(error)
+    } catch {
+        throw error
+    }
+}
+