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| 1 | +/* |
| 2 | + * Copyright 2025 Google LLC |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +package com.google.firebase.ai |
| 18 | + |
| 19 | +import android.graphics.Bitmap |
| 20 | +import com.google.firebase.ai.type.Content |
| 21 | +import com.google.firebase.ai.type.GenerateContentResponse |
| 22 | +import com.google.firebase.ai.type.ImagePart |
| 23 | +import com.google.firebase.ai.type.InlineDataPart |
| 24 | +import com.google.firebase.ai.type.InvalidStateException |
| 25 | +import com.google.firebase.ai.type.PublicPreviewAPI |
| 26 | +import com.google.firebase.ai.type.TextPart |
| 27 | +import com.google.firebase.ai.type.content |
| 28 | +import java.util.LinkedList |
| 29 | +import java.util.concurrent.Semaphore |
| 30 | +import kotlinx.coroutines.flow.Flow |
| 31 | +import kotlinx.coroutines.flow.onCompletion |
| 32 | +import kotlinx.coroutines.flow.onEach |
| 33 | + |
| 34 | +/** |
| 35 | + * Representation of a multi-turn interaction with a model. |
| 36 | + * |
| 37 | + * Captures and stores the history of communication in memory, and provides it as context with each |
| 38 | + * new message. |
| 39 | + * |
| 40 | + * **Note:** This object is not thread-safe, and calling [sendMessage] multiple times without |
| 41 | + * waiting for a response will throw an [InvalidStateException]. |
| 42 | + * |
| 43 | + * @param model The model to use for the interaction. |
| 44 | + * @param templateID The template ID for this chat session |
| 45 | + * @property history The previous content from the chat that has been successfully sent and received |
| 46 | + * from the model. This will be provided to the model for each message sent (as context for the |
| 47 | + * discussion). |
| 48 | + */ |
| 49 | +@PublicPreviewAPI |
| 50 | +public class TemplateChat( |
| 51 | + private val model: TemplateGenerativeModel, |
| 52 | + private val templateID: String, |
| 53 | + public val history: MutableList<Content> = ArrayList() |
| 54 | +) { |
| 55 | + private var lock = Semaphore(1) |
| 56 | + |
| 57 | + /** |
| 58 | + * Sends a message using the provided [prompt]; automatically providing the existing [history] as |
| 59 | + * context. |
| 60 | + * |
| 61 | + * If successful, the message and response will be added to the [history]. If unsuccessful, |
| 62 | + * [history] will remain unchanged. |
| 63 | + * |
| 64 | + * @param prompt The input that, together with the history, will be given to the model as the |
| 65 | + * prompt. |
| 66 | + * @param inputs the inputs needed to fill in the template ID |
| 67 | + * @throws InvalidStateException if [prompt] is not coming from the 'user' role. |
| 68 | + * @throws InvalidStateException if the [Chat] instance has an active request. |
| 69 | + */ |
| 70 | + public suspend fun sendMessage( |
| 71 | + prompt: Content, |
| 72 | + inputs: Map<String, Any> |
| 73 | + ): GenerateContentResponse { |
| 74 | + prompt.assertComesFromUser() |
| 75 | + attemptLock() |
| 76 | + try { |
| 77 | + val fullPrompt = history + prompt |
| 78 | + val response = model.generateContent(templateID, inputs, fullPrompt) |
| 79 | + history.add(prompt) |
| 80 | + history.add(response.candidates.first().content) |
| 81 | + return response |
| 82 | + } finally { |
| 83 | + lock.release() |
| 84 | + } |
| 85 | + } |
| 86 | + |
| 87 | + /** |
| 88 | + * Sends a message using the existing history of this chat as context and the provided [Content] |
| 89 | + * prompt. |
| 90 | + * |
| 91 | + * The response from the model is returned as a stream. |
| 92 | + * |
| 93 | + * If successful, the message and response will be added to the history. If unsuccessful, history |
| 94 | + * will remain unchanged. |
| 95 | + * |
| 96 | + * @param prompt The input that, together with the history, will be given to the model as the |
| 97 | + * prompt. |
| 98 | + * @param inputs the inputs needed to fill in the template ID |
| 99 | + * @throws InvalidStateException if [prompt] is not coming from the 'user' role. |
| 100 | + * @throws InvalidStateException if the [Chat] instance has an active request. |
| 101 | + */ |
| 102 | + public fun sendMessageStream( |
| 103 | + prompt: Content, |
| 104 | + inputs: Map<String, Any> |
| 105 | + ): Flow<GenerateContentResponse> { |
| 106 | + prompt.assertComesFromUser() |
| 107 | + attemptLock() |
| 108 | + |
| 109 | + val fullPrompt = history + prompt |
| 110 | + val flow = model.generateContentStream(templateID, inputs, fullPrompt) |
| 111 | + val bitmaps = LinkedList<Bitmap>() |
| 112 | + val inlineDataParts = LinkedList<InlineDataPart>() |
| 113 | + val text = StringBuilder() |
| 114 | + |
| 115 | + /** |
| 116 | + * TODO: revisit when images and inline data are returned. This will cause issues with how |
| 117 | + * things are structured in the response. eg; a text/image/text response will be (incorrectly) |
| 118 | + * represented as image/text |
| 119 | + */ |
| 120 | + return flow |
| 121 | + .onEach { |
| 122 | + for (part in it.candidates.first().content.parts) { |
| 123 | + when (part) { |
| 124 | + is TextPart -> text.append(part.text) |
| 125 | + is ImagePart -> bitmaps.add(part.image) |
| 126 | + is InlineDataPart -> inlineDataParts.add(part) |
| 127 | + } |
| 128 | + } |
| 129 | + } |
| 130 | + .onCompletion { |
| 131 | + lock.release() |
| 132 | + if (it == null) { |
| 133 | + val content = |
| 134 | + content("model") { |
| 135 | + for (bitmap in bitmaps) { |
| 136 | + image(bitmap) |
| 137 | + } |
| 138 | + for (inlineDataPart in inlineDataParts) { |
| 139 | + inlineData(inlineDataPart.inlineData, inlineDataPart.mimeType) |
| 140 | + } |
| 141 | + if (text.isNotBlank()) { |
| 142 | + text(text.toString()) |
| 143 | + } |
| 144 | + } |
| 145 | + |
| 146 | + history.add(prompt) |
| 147 | + history.add(content) |
| 148 | + } |
| 149 | + } |
| 150 | + } |
| 151 | + |
| 152 | + private fun Content.assertComesFromUser() { |
| 153 | + if (role !in listOf("user", "function")) { |
| 154 | + throw InvalidStateException("Chat prompts should come from the 'user' or 'function' role.") |
| 155 | + } |
| 156 | + } |
| 157 | + |
| 158 | + private fun attemptLock() { |
| 159 | + if (!lock.tryAcquire()) { |
| 160 | + throw InvalidStateException( |
| 161 | + "This chat instance currently has an ongoing request, please wait for it to complete " + |
| 162 | + "before sending more messages" |
| 163 | + ) |
| 164 | + } |
| 165 | + } |
| 166 | +} |
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