using AllInAI.Sharp.API.Extensions;
using AllInAI.Sharp.API.IService;
using AllInAI.Sharp.API.Req;
using AllInAI.Sharp.API.Res;
using AllInAI.Sharp.API.Utils;
using System;
using System.Text.Json;

namespace AllInAI.Sharp.API.Service;

public class AliChatService: IChatService
{
 public async Task<CompletionRes> Completion(HttpClient _httpClient,CompletionReq req, string? accesstoken = null, CancellationToken cancellationToken = default)
 {
 AliCompletionReq aliReq = new AliCompletionReq();
 aliReq.Model=req.Model;
 aliReq.Input.Messages = req.Messages;
 aliReq.Parameters.TopP = req.TopP;
 aliReq.Parameters.MaxTokens=req.MaxTokens;
 string url = "/api/v1/services/aigc/text-generation/generation";
 AliCompletionRes completionRes = await _httpClient.PostAndReadAsAsync<AliCompletionRes>(url, aliReq, cancellationToken);
 CompletionRes res = GetCompletion(completionRes);
 res.Model = req.Model;
 return res;
 }

 public async IAsyncEnumerable<CompletionRes> CompletionStream(HttpClient _httpClient,CompletionReq req, string? accesstoken = null, CancellationToken cancellationToken = default)
 {
 AliCompletionReq aliReq = new AliCompletionReq();
 aliReq.Model = req.Model;
 aliReq.Input.Messages = req.Messages;
 aliReq.Parameters.TopP = req.TopP;
 aliReq.Parameters.MaxTokens = req.MaxTokens;
 aliReq.Parameters.IncrementalOutput = true;
 //aliReq.Parameters.ResultFormat = "text";
 string url = "/api/v1/services/aigc/text-generation/generation";
 using var response = _httpClient.PostAsStreamAsync(url, aliReq, cancellationToken);
 await using var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
 using var reader = new StreamReader(stream);
 while (!reader.EndOfStream) {
 cancellationToken.ThrowIfCancellationRequested();

 var line = await reader.ReadLineAsync();
 // Skip empty lines
 if (string.IsNullOrEmpty(line)) {
 continue;
 }
 if(line.StartsWith("id:") || line.StartsWith("event:result") || line.StartsWith(":HTTP_STATUS/200")) {
 continue;
 }
 line = line.RemoveIfStartWith("data:");

 CompletionRes res;
 try {
 res = new CompletionRes();
 // When the response is good, each line is a serializable CompletionCreateRequest
 var completionRes = JsonSerializer.Deserialize<AliCompletionRes>(line);
 // Exit the loop if the stream is done
 // if (completionRes.Output.FinishReason == "stop" || completionRes.Output.Choices[0].FinishReason == "stop") {
 // break;
 // }
 res = GetCompletion(completionRes);
 res.Model = req.Model;
 }
 catch (Exception) {
 // When the API returns an error, it does not come back as a block, it returns a single character of text ("{").
 // In this instance, read through the rest of the response, which should be a complete object to parse.
 line += await reader.ReadToEndAsync();
 res = JsonSerializer.Deserialize<CompletionRes>(line);
 }
 if (null != res) {
 yield return res;
 }
 }
 }

 public Task<EmbeddingRes> Embedding(HttpClient _httpClient, EmbeddingReq req, string? accesstoken = null, CancellationToken cancellationToken = default) {
 throw new NotImplementedException();
 }

 private CompletionRes GetCompletion(AliCompletionRes completionRes) {
 CompletionRes res = new CompletionRes();
 if (completionRes != null) {
 res.Error = completionRes.Error;
 if (completionRes.Error != null) { return res; }
 if (string.IsNullOrEmpty(completionRes.Output.Text)) {
 res.Choices = completionRes.Output.Choices;
 if (completionRes.Output.Choices != null)
 res.Result = completionRes.Output.Choices[0].Message.Content;
 }
 else {
 res.Result = completionRes.Output.Text;
 }
 res.Usage = new UsageRes();
 res.Usage.PromptTokens = completionRes.Usage.InputTokens;
 res.Usage.CompletionTokens = completionRes.Usage.OutputTokens;
 }
 return res;
 }
}