using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using OllamaSharp;
using OllamaSharp.Models;
using xAiApi.Configurations;
using xAiApi.Constants;
using xAiApi.Extensions;
using xAiApi.Interfaces;
using xAiApi.Models;
using xAiModels.Interfaces;
using xAiService.Helpers;
using xCommons.Extensions;
using xExceptions.Constants;

namespace xAiApi.Providers
{
    /// <summary>
    /// Base Embedding Provider Service ...
    /// </summary>
    public abstract class XAiEmbeddingServiceBase : XAIServiceBase, IXAiEmbeddingServiceBase
    {
        private readonly XAiModelDescriptor descriptor;

        protected XAiEmbeddingServiceBase(
            IXAiDataProvider dataProvider,
            XAiApiConfiguration configuration,
            ILogger<XAiEmbeddingServiceBase> logger,
            string embeddingModelName = XAiApiConstants.XAiEmbeddingModelName
        ) : base(
            dataProvider,
            logger,
            configuration
        )
        {
            //
            // Prepare Embedding Model Descriptor ...
            descriptor = configuration.GetModel(embeddingModelName);
            if (!descriptor.IsValid())
            {
                XException.InvalidConfiguration.Throw();
            }
        }

        /// <summary>
        /// Embedding Specified String ...
        /// </summary>
        /// <param name="content"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public virtual async Task<float[]> Embeding(
            string content,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Validate ...
            if (content.IsNullOrEmpty())
            {
                XException.InvalidArgs.Throw();
            }

            //
            // Retrieve Ollama Client ...
            using var client = GetEmbeddingClient();

            //
            // Create Embeding Request ....
            var request = new EmbedRequest
            {
                Input = [content],
                Model = descriptor.LLM,
            };

            //
            // Make Request and Recieve Response ...
            var response = await client.EmbedAsync(
                request: request,
                cancellationToken: cancellationToken
            );
            if (response.IsNullOrDefault())
            {
                XException.ActionFailed.Throw();
            }

            //
            // Generae Result ...
            var result = response?
                .Embeddings?
                .FirstOrDefault()
                ?? [];
            if (result.Length == 0)
            {
                XException.ActionFailed.Throw();
            }

            //
            // Normalize ...
            VectorHelper.Normalize(result);

            //
            return result;
        }

        /// <summary>
        /// Embedding Specified Batch ...
        /// </summary>
        /// <param name="batch"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public virtual async Task<IReadOnlyList<float[]>> Embedings(
            string[] batch,
            CancellationToken cancellationToken = default

        )
        {
            //
            // Validate ...
            if (!batch.HasChild() ||
                !batch.All(x => !x.IsNullOrEmpty())
            )
            {
                XException.InvalidArgs.Throw();
            }

            //
            // Retrieve Ollama Client ...
            using var client = GetEmbeddingClient();

            //
            // Create Embeding Request ....
            var request = new EmbedRequest
            {
                Input = [.. batch],
                Model = descriptor.LLM,
            };

            //
            // Make Request and Recieve Response ...
            var response = await client.EmbedAsync(
                request: request,
                cancellationToken: cancellationToken
            );
            if (response.IsNullOrDefault())
            {
                XException.ActionFailed.Throw();
            }

            //
            // Generae Result ...
            var result = response?
                .Embeddings
                .ToArray()
                ?? [];

            //
            // Validate Result ...
            if (result.Length == 0)
            {
                XException.ActionFailed.Throw();
            }

            //
            // Normalize ...
            foreach (var vector in result)
            {
                VectorHelper.Normalize(vector);
            }

            //
            return result;
        }

        /// <summary>
        /// Access Embedding Client ...
        /// </summary>
        /// <returns></returns>
        public OllamaApiClient GetEmbeddingClient()
        {
            //
            var result = new OllamaApiClient(new Uri(descriptor.Url));

            //
            return result;
        }
    }
}