import type { BaseLanguageModelCallOptions } from "@langchain/core/language_models/base";
import {
    SimpleChatModel,
    type BaseChatModelParams,
} from "@langchain/core/language_models/chat_models";
import { CallbackManagerForLLMRun } from "@langchain/core/callbacks/manager";
import {
    AIMessageChunk,
    BaseMessage,
    ChatMessage,
} from "@langchain/core/messages";
import { ChatGenerationChunk } from "@langchain/core/outputs";
import type { StringWithAutocomplete } from "@langchain/core/utils/types";

import {
    createOllamaChatStream,
    createOllamaGenerateStream,
    parseKeepAlive,
    type OllamaInput,
    type OllamaMessage,
} from "./utils/ollama";

export interface ChatOllamaInput extends OllamaInput { }

export interface ChatOllamaCallOptions extends BaseLanguageModelCallOptions { }

export class ChatOllama
    extends SimpleChatModel<ChatOllamaCallOptions>
    implements ChatOllamaInput {
    static lc_name() {
        return "ChatOllama";
    }

    lc_serializable = true;

    model = "llama2";

    baseUrl = "http://localhost:11434";

    keepAlive = "5m";

    embeddingOnly?: boolean;

    f16KV?: boolean;

    frequencyPenalty?: number;

    headers?: Record<string, string>;

    logitsAll?: boolean;

    lowVram?: boolean;

    mainGpu?: number;

    mirostat?: number;

    mirostatEta?: number;

    mirostatTau?: number;

    numBatch?: number;

    numCtx?: number;

    numGpu?: number;

    numGqa?: number;

    numKeep?: number;

    numPredict?: number;

    numThread?: number;

    penalizeNewline?: boolean;

    presencePenalty?: number;

    repeatLastN?: number;

    repeatPenalty?: number;

    ropeFrequencyBase?: number;

    ropeFrequencyScale?: number;

    temperature?: number;

    stop?: string[];

    tfsZ?: number;

    topK?: number;

    topP?: number;

    typicalP?: number;

    useMLock?: boolean;

    useMMap?: boolean;

    vocabOnly?: boolean;

    seed?: number;

    format?: StringWithAutocomplete<"json">;

    constructor(fields: OllamaInput & BaseChatModelParams) {
        super(fields);
        this.model = fields.model ?? this.model;
        this.baseUrl = fields.baseUrl?.endsWith("/")
            ? fields.baseUrl.slice(0, -1)
            : fields.baseUrl ?? this.baseUrl;
        this.keepAlive = parseKeepAlive(fields.keepAlive) ?? this.keepAlive;
        this.embeddingOnly = fields.embeddingOnly;
        this.f16KV = fields.f16KV;
        this.frequencyPenalty = fields.frequencyPenalty;
        this.headers = fields.headers;
        this.logitsAll = fields.logitsAll;
        this.lowVram = fields.lowVram;
        this.mainGpu = fields.mainGpu;
        this.mirostat = fields.mirostat;
        this.mirostatEta = fields.mirostatEta;
        this.mirostatTau = fields.mirostatTau;
        this.numBatch = fields.numBatch;
        this.numCtx = fields.numCtx;
        this.numGpu = fields.numGpu === null ? undefined : fields.numGpu;
        this.numGqa = fields.numGqa;
        this.numKeep = fields.numKeep;
        this.numPredict = fields.numPredict;
        this.numThread = fields.numThread;
        this.penalizeNewline = fields.penalizeNewline;
        this.presencePenalty = fields.presencePenalty;
        this.repeatLastN = fields.repeatLastN;
        this.repeatPenalty = fields.repeatPenalty;
        this.ropeFrequencyBase = fields.ropeFrequencyBase;
        this.ropeFrequencyScale = fields.ropeFrequencyScale;
        this.temperature = fields.temperature;
        this.stop = fields.stop;
        this.tfsZ = fields.tfsZ;
        this.topK = fields.topK;
        this.topP = fields.topP;
        this.typicalP = fields.typicalP;
        this.useMLock = fields.useMLock;
        this.useMMap = fields.useMMap;
        this.vocabOnly = fields.vocabOnly;
        this.format = fields.format;
        this.seed = fields.seed;
    }

    protected getLsParams(options: this["ParsedCallOptions"]) {
        const params = this.invocationParams(options);
        return {
            ls_provider: "ollama",
            ls_model_name: this.model,
            ls_model_type: "chat",
            ls_temperature: this.temperature ?? undefined,
            ls_stop: this.stop,
            ls_max_tokens: params.options.num_predict,
        };
    }

    _llmType() {
        return "ollama";
    }

    /**
     * A method that returns the parameters for an Ollama API call. It
     * includes model and options parameters.
     * @param options Optional parsed call options.
     * @returns An object containing the parameters for an Ollama API call.
     */
    invocationParams(options?: this["ParsedCallOptions"]) {
        return {
            model: this.model,
            format: this.format,
            keep_alive: this.keepAlive,
            options: {
                embedding_only: this.embeddingOnly,
                f16_kv: this.f16KV,
                frequency_penalty: this.frequencyPenalty,
                logits_all: this.logitsAll,
                low_vram: this.lowVram,
                main_gpu: this.mainGpu,
                mirostat: this.mirostat,
                mirostat_eta: this.mirostatEta,
                mirostat_tau: this.mirostatTau,
                num_batch: this.numBatch,
                num_ctx: this.numCtx,
                num_gpu: this.numGpu,
                num_gqa: this.numGqa,
                num_keep: this.numKeep,
                num_predict: this.numPredict,
                num_thread: this.numThread,
                penalize_newline: this.penalizeNewline,
                presence_penalty: this.presencePenalty,
                repeat_last_n: this.repeatLastN,
                repeat_penalty: this.repeatPenalty,
                rope_frequency_base: this.ropeFrequencyBase,
                rope_frequency_scale: this.ropeFrequencyScale,
                temperature: this.temperature,
                stop: options?.stop ?? this.stop,
                tfs_z: this.tfsZ,
                top_k: this.topK,
                top_p: this.topP,
                typical_p: this.typicalP,
                use_mlock: this.useMLock,
                use_mmap: this.useMMap,
                vocab_only: this.vocabOnly,
                seed: this.seed,
            },
        };
    }

    _combineLLMOutput() {
        return {};
    }

    /** @deprecated */
    async *_streamResponseChunksLegacy(
        input: BaseMessage[],
        options: this["ParsedCallOptions"],
        runManager?: CallbackManagerForLLMRun
    ): AsyncGenerator<ChatGenerationChunk> {
        const stream = createOllamaGenerateStream(
            this.baseUrl,
            {
                ...this.invocationParams(options),
                prompt: this._formatMessagesAsPrompt(input),
            },
            {
                ...options,
                headers: this.headers,
            }
        );
        for await (const chunk of stream) {
            if (!chunk.done) {
                yield new ChatGenerationChunk({
                    text: chunk.response,
                    message: new AIMessageChunk({ content: chunk.response }),
                });
                await runManager?.handleLLMNewToken(chunk.response ?? "");
            } else {
                yield new ChatGenerationChunk({
                    text: "",
                    message: new AIMessageChunk({ content: "" }),
                    generationInfo: {
                        model: chunk.model,
                        total_duration: chunk.total_duration,
                        load_duration: chunk.load_duration,
                        prompt_eval_count: chunk.prompt_eval_count,
                        prompt_eval_duration: chunk.prompt_eval_duration,
                        eval_count: chunk.eval_count,
                        eval_duration: chunk.eval_duration,
                    },
                });
            }
        }
    }

    async *_streamResponseChunks(
        input: BaseMessage[],
        options: this["ParsedCallOptions"],
        runManager?: CallbackManagerForLLMRun
    ): AsyncGenerator<ChatGenerationChunk> {
        try {
            const stream = await this.caller.call(async () =>
                createOllamaChatStream(
                    this.baseUrl,
                    {
                        ...this.invocationParams(options),
                        messages: this._convertMessagesToOllamaMessages(input),
                    },
                    {
                        ...options,
                        headers: this.headers,
                    }
                )
            );
            for await (const chunk of stream) {
                if (!chunk.done) {
                    yield new ChatGenerationChunk({
                        text: chunk.message.content,
                        message: new AIMessageChunk({ content: chunk.message.content }),
                    });
                    await runManager?.handleLLMNewToken(chunk.message.content ?? "");
                } else {
                    yield new ChatGenerationChunk({
                        text: "",
                        message: new AIMessageChunk({ content: "" }),
                        generationInfo: {
                            model: chunk.model,
                            total_duration: chunk.total_duration,
                            load_duration: chunk.load_duration,
                            prompt_eval_count: chunk.prompt_eval_count,
                            prompt_eval_duration: chunk.prompt_eval_duration,
                            eval_count: chunk.eval_count,
                            eval_duration: chunk.eval_duration,
                        },
                    });
                }
            }
            // eslint-disable-next-line @typescript-eslint/no-explicit-any
        } catch (e: any) {
            if (e.response?.status === 404) {
                console.warn(
                    "[WARNING]: It seems you are using a legacy version of Ollama. Please upgrade to a newer version for better chat support."
                );
                yield* this._streamResponseChunksLegacy(input, options, runManager);
            } else {
                throw e;
            }
        }
    }

    protected _convertMessagesToOllamaMessages(
        messages: BaseMessage[]
    ): OllamaMessage[] {
        return messages.map((message) => {
            let role;
            if (message._getType() === "human") {
                role = "user";
            } else if (message._getType() === "ai") {
                role = "assistant";
            } else if (message._getType() === "system") {
                role = "system";
            } else {
                throw new Error(
                    `Unsupported message type for Ollama: ${message._getType()}`
                );
            }
            let content = "";
            const images = [];
            if (typeof message.content === "string") {
                content = message.content;
            } else {
                for (const contentPart of message.content) {
                    if (contentPart.type === "text") {
                        content = `${content}\n${contentPart.text}`;
                    } else if (
                        contentPart.type === "image_url" &&
                        typeof contentPart.image_url === "string"
                    ) {
                        const imageUrlComponents = contentPart.image_url.split(",");
                        // Support both data:image/jpeg;base64,<image> format as well
                        images.push(imageUrlComponents[1] ?? imageUrlComponents[0]);
                    } else {
                        throw new Error(
                            `Unsupported message content type. Must either have type "text" or type "image_url" with a string "image_url" field.`
                        );
                    }
                }
            }
            return {
                role,
                content,
                images,
            };
        });
    }

    /** @deprecated */
    protected _formatMessagesAsPrompt(messages: BaseMessage[]): string {
        const formattedMessages = messages
            .map((message) => {
                let messageText;
                if (message._getType() === "human") {
                    messageText = `[INST] ${message.content} [/INST]`;
                } else if (message._getType() === "ai") {
                    messageText = message.content;
                } else if (message._getType() === "system") {
                    messageText = `<<SYS>> ${message.content} <</SYS>>`;
                } else if (ChatMessage.isInstance(message)) {
                    messageText = `\n\n${message.role[0].toUpperCase()}${message.role.slice(
                        1
                    )}: ${message.content}`;
                } else {
                    console.warn(
                        `Unsupported message type passed to Ollama: "${message._getType()}"`
                    );
                    messageText = "";
                }
                return messageText;
            })
            .join("\n");
        return formattedMessages;
    }

    /** @ignore */
    async _call(
        messages: BaseMessage[],
        options: this["ParsedCallOptions"],
        runManager?: CallbackManagerForLLMRun
    ): Promise<string> {
        const chunks = [];
        for await (const chunk of this._streamResponseChunks(
            messages,
            options,
            runManager
        )) {
            chunks.push(chunk.message.content);
        }
        return chunks.join("");
    }
}