"""Ollama embeddings models."""

from __future__ import annotations

from typing import Any

from langchain_core.embeddings import Embeddings
from ollama import AsyncClient, Client
from pydantic import (
    BaseModel,
    ConfigDict,
    PrivateAttr,
    field_validator,
    model_validator,
)
from typing_extensions import Self

from langchain_ollama._utils import (
    merge_auth_headers,
    parse_url_with_auth,
    validate_model,
)


class OllamaEmbeddings(BaseModel, Embeddings):
    """Ollama embedding model integration.

    Set up a local Ollama instance:
        [Install the Ollama package](https://github.com/ollama/ollama) and set up a
        local Ollama instance.

        You will need to choose a model to serve.

        You can view a list of available models via [the model library](https://ollama.com/library).

        To fetch a model from the Ollama model library use `ollama pull <name-of-model>`.

        For example, to pull the llama3 model:

        ```bash
        ollama pull llama3
        ```

        This will download the default tagged version of the model.
        Typically, the default points to the latest, smallest sized-parameter model.

        * On Mac, the models will be downloaded to `~/.ollama/models`
        * On Linux (or WSL), the models will be stored at `/usr/share/ollama/.ollama/models`

        You can specify the exact version of the model of interest
        as such `ollama pull vicuna:13b-v1.5-16k-q4_0`.

        To view pulled models:

        ```bash
        ollama list
        ```

        To start serving:

        ```bash
        ollama serve
        ```

        View the Ollama documentation for more commands.

        ```bash
        ollama help
        ```

    Install the `langchain-ollama` integration package:
        ```bash
        pip install -U langchain_ollama
        ```

    Key init args — completion params:
        model: str
            Name of Ollama model to use.
        base_url: str | None
            Base url the model is hosted under.

    See full list of supported init args and their descriptions in the params section.

    Instantiate:
        ```python
        from langchain_ollama import OllamaEmbeddings

        embed = OllamaEmbeddings(model="llama3")
        ```

    Embed single text:
        ```python
        input_text = "The meaning of life is 42"
        vector = embed.embed_query(input_text)
        print(vector[:3])
        ```

        ```python
        [-0.024603435769677162, -0.007543657906353474, 0.0039630369283258915]
        ```

    Embed multiple texts:
        ```python
        input_texts = ["Document 1...", "Document 2..."]
        vectors = embed.embed_documents(input_texts)
        print(len(vectors))
        # The first 3 coordinates for the first vector
        print(vectors[0][:3])
        ```

        ```python
        2
        [-0.024603435769677162, -0.007543657906353474, 0.0039630369283258915]
        ```

    Async:
        ```python
        vector = await embed.aembed_query(input_text)
        print(vector[:3])

        # multiple:
        # await embed.aembed_documents(input_texts)
        ```

        ```python
        [-0.009100092574954033, 0.005071679595857859, -0.0029193938244134188]
        ```
    """  # noqa: E501

    model: str
    """Model name to use."""

    dimensions: int | None = None
    """Number of dimensions for the output embedding vectors.

    If not provided, the model's default embedding dimensionality is used.
    """

    @field_validator("dimensions")
    @classmethod
    def _validate_dimensions(cls, v: int | None) -> int | None:
        if v is not None and v < 1:
            msg = "`dimensions` must be a positive integer."
            raise ValueError(msg)
        return v

    validate_model_on_init: bool = False
    """Whether to validate the model exists in ollama locally on initialization.

    !!! version-added "Added in `langchain-ollama` 0.3.4"

    """

    base_url: str | None = None
    """Base url the model is hosted under.

    If none, defaults to the Ollama client default.

    Supports `userinfo` auth in the format `http://username:password@localhost:11434`.
    Useful if your Ollama server is behind a proxy.

    !!! warning
        `userinfo` is not secure and should only be used for local testing or
        in secure environments. Avoid using it in production or over unsecured
        networks.

    !!! note
        If using `userinfo`, ensure that the Ollama server is configured to
        accept and validate these credentials.

    !!! note
        `userinfo` headers are passed to both sync and async clients.

    """

    client_kwargs: dict | None = {}
    """Additional kwargs to pass to the httpx clients. Pass headers in here.

    These arguments are passed to both synchronous and async clients.

    Use `sync_client_kwargs` and `async_client_kwargs` to pass different arguments
    to synchronous and asynchronous clients.
    """

    async_client_kwargs: dict | None = {}
    """Additional kwargs to merge with `client_kwargs` before passing to httpx client.

    These are clients unique to the async client; for shared args use `client_kwargs`.

    For a full list of the params, see the [httpx documentation](https://www.python-httpx.org/api/#asyncclient).
    """

    sync_client_kwargs: dict | None = {}
    """Additional kwargs to merge with `client_kwargs` before passing to httpx client.

    These are clients unique to the sync client; for shared args use `client_kwargs`.

    For a full list of the params, see the [httpx documentation](https://www.python-httpx.org/api/#client).
    """

    _client: Client | None = PrivateAttr(default=None)
    """The client to use for making requests."""

    _async_client: AsyncClient | None = PrivateAttr(default=None)
    """The async client to use for making requests."""

    mirostat: int | None = None
    """Enable Mirostat sampling for controlling perplexity.
    (default: `0`, `0` = disabled, `1` = Mirostat, `2` = Mirostat 2.0)"""

    mirostat_eta: float | None = None
    """Influences how quickly the algorithm responds to feedback
    from the generated text. A lower learning rate will result in
    slower adjustments, while a higher learning rate will make
    the algorithm more responsive. (Default: `0.1`)"""

    mirostat_tau: float | None = None
    """Controls the balance between coherence and diversity
    of the output. A lower value will result in more focused and
    coherent text. (Default: `5.0`)"""

    num_ctx: int | None = None
    """Sets the size of the context window used to generate the
    next token. (Default: `2048`)	"""

    num_gpu: int | None = None
    """The number of GPUs to use. On macOS it defaults to `1` to
    enable metal support, `0` to disable."""

    keep_alive: int | None = None
    """Controls how long the model will stay loaded into memory
    following the request (default: `5m`)
    """

    num_thread: int | None = None
    """Sets the number of threads to use during computation.
    By default, Ollama will detect this for optimal performance.
    It is recommended to set this value to the number of physical
    CPU cores your system has (as opposed to the logical number of cores)."""

    repeat_last_n: int | None = None
    """Sets how far back for the model to look back to prevent
    repetition. (Default: `64`, `0` = disabled, `-1` = `num_ctx`)"""

    repeat_penalty: float | None = None
    """Sets how strongly to penalize repetitions. A higher value (e.g., `1.5`)
    will penalize repetitions more strongly, while a lower value (e.g., `0.9`)
    will be more lenient. (Default: `1.1`)"""

    temperature: float | None = None
    """The temperature of the model. Increasing the temperature will
    make the model answer more creatively. (Default: `0.8`)"""

    stop: list[str] | None = None
    """Sets the stop tokens to use."""

    tfs_z: float | None = None
    """Tail free sampling is used to reduce the impact of less probable
    tokens from the output. A higher value (e.g., `2.0`) will reduce the
    impact more, while a value of `1.0` disables this setting. (default: `1`)"""

    top_k: int | None = None
    """Reduces the probability of generating nonsense. A higher value (e.g. `100`)
    will give more diverse answers, while a lower value (e.g. `10`)
    will be more conservative. (Default: `40`)"""

    top_p: float | None = None
    """Works together with top-k. A higher value (e.g., `0.95`) will lead
    to more diverse text, while a lower value (e.g., `0.5`) will
    generate more focused and conservative text. (Default: `0.9`)"""

    model_config = ConfigDict(
        extra="forbid",
    )

    @property
    def _default_params(self) -> dict[str, Any]:
        """Get the default parameters for calling Ollama."""
        return {
            "mirostat": self.mirostat,
            "mirostat_eta": self.mirostat_eta,
            "mirostat_tau": self.mirostat_tau,
            "num_ctx": self.num_ctx,
            "num_gpu": self.num_gpu,
            "num_thread": self.num_thread,
            "repeat_last_n": self.repeat_last_n,
            "repeat_penalty": self.repeat_penalty,
            "temperature": self.temperature,
            "stop": self.stop,
            "tfs_z": self.tfs_z,
            "top_k": self.top_k,
            "top_p": self.top_p,
        }

    @model_validator(mode="after")
    def _set_clients(self) -> Self:
        """Set clients to use for Ollama."""
        client_kwargs = self.client_kwargs or {}

        cleaned_url, auth_headers = parse_url_with_auth(self.base_url)
        merge_auth_headers(client_kwargs, auth_headers)

        sync_client_kwargs = client_kwargs
        if self.sync_client_kwargs:
            sync_client_kwargs = {**sync_client_kwargs, **self.sync_client_kwargs}

        async_client_kwargs = client_kwargs
        if self.async_client_kwargs:
            async_client_kwargs = {**async_client_kwargs, **self.async_client_kwargs}

        self._client = Client(host=cleaned_url, **sync_client_kwargs)
        self._async_client = AsyncClient(host=cleaned_url, **async_client_kwargs)
        if self.validate_model_on_init:
            validate_model(self._client, self.model)
        return self

    def embed_documents(self, texts: list[str]) -> list[list[float]]:
        """Embed search docs."""
        if not self._client:
            msg = (
                "Ollama sync client is not initialized. "
                "Make sure the model was properly constructed."
            )
            raise RuntimeError(msg)
        return self._client.embed(
            self.model,
            texts,
            dimensions=self.dimensions,
            options=self._default_params,
            keep_alive=self.keep_alive,
        )["embeddings"]

    def embed_query(self, text: str) -> list[float]:
        """Embed query text."""
        return self.embed_documents([text])[0]

    async def aembed_documents(self, texts: list[str]) -> list[list[float]]:
        """Embed search docs."""
        if not self._async_client:
            msg = (
                "Ollama async client is not initialized. "
                "Make sure the model was properly constructed."
            )
            raise RuntimeError(msg)
        return (
            await self._async_client.embed(
                self.model,
                texts,
                dimensions=self.dimensions,
                options=self._default_params,
                keep_alive=self.keep_alive,
            )
        )["embeddings"]

    async def aembed_query(self, text: str) -> list[float]:
        """Embed query text."""
        return (await self.aembed_documents([text]))[0]
