using System.ClientModel;
using OpenAI;
using OpenAI.Chat;
using OpenAI.Embeddings;

// ── Settings ──────────────────────────────────────────────────
string lmStudioUrl   = "http://localhost:1234/v1";
string embeddingModel = "text-embedding-qwen3-embedding-8b";                // embedding model loaded in LM Studio
string chatModel      = "qwen3.5-9b";                             // chat model loaded in LM Studio

// ── 1. Our "documents" — 2026 news the model does NOT know ──
// These are recent events. The AI model was trained on older data,
// so without RAG it would hallucinate or say "I don't know."
string[] documents = new[]
{
    // 1. T20 World Cup 2026 Final (Detailed)
    "ICC Men's T20 World Cup 2026 Final: India defeated New Zealand in the final to win the championship. " +
    "The match was held at the Narendra Modi Stadium in Ahmedabad. India scored 255/5 in 20 overs, while New Zealand " +
    "were bowled out for 159 in 19 overs. India won the match by 96 runs. " +
    "Sanju Samson was the top scorer in the final with 89 runs off 46 balls, while Ishan Kishan contributed 54 runs. " +
    "Jasprit Bumrah delivered an outstanding bowling performance, taking 4 wickets for 15 runs. " +
    "Sanju Samson was named Player of the Match for his innings, and he was also awarded Player of the Tournament for his consistent performance.",

    // 2. Iran–Israel Conflict
    "Iran–Israel Conflict 2026 Detailed: In early 2026, tensions between Iran and Israel escalated into direct confrontation " +
    "involving missile strikes, drone warfare, and cyber attacks. The conflict significantly impacted global energy markets, " +
    "especially oil and gas supply routes through the Strait of Hormuz. Several countries, including the United States, urged " +
    "de-escalation while increasing military readiness. The conflict also contributed to rising global fuel prices and economic uncertainty. " +
    "The situation remains volatile with ongoing diplomatic negotiations.",

    // 3. Kerala Assembly Election 2026
    "Kerala Assembly Election 2026 Full Schedule: The Election Commission of India announced the election schedule in March 2026. " +
    "Notification was issued on 16 March 2026. The last date for nominations was 23 March, with scrutiny on 24 March. " +
    "The last date for withdrawal was 26 March. Voting will be conducted on 9 April 2026 in a single phase. " +
    "The counting of votes and declaration of results will take place on 4 May 2026. " +
    "The main political alliances are the LDF led by CPI(M) and the UDF led by Congress, with the NDA also contesting."
};

// ── 2. Create clients ────────────────────────────────────────
var options = new OpenAIClientOptions { Endpoint = new Uri(lmStudioUrl) };
var credential = new ApiKeyCredential("lm-studio");

var embeddingClient = new EmbeddingClient(embeddingModel, credential, options);
var chatClient      = new ChatClient(chatModel, credential, options);

// ── 3. Embed all documents (one-time preparation) ────────────
Console.WriteLine("Embedding 2026 news documents...");

var docEmbeddings = new List<(string Text, float[] Vector)>();

foreach (string doc in documents)
{
    var result = await embeddingClient.GenerateEmbeddingAsync(doc);
    docEmbeddings.Add((doc, result.Value.ToFloats().ToArray()));
}

Console.WriteLine($"Embedded {docEmbeddings.Count} news chunks.\n");

// ── 4. Ask a question about 2026 ─────────────────────────────
string question = "Who won the T20 World Cup in 2026?";
Console.WriteLine($"Question: {question}\n");

// ── 5. Embed the question ────────────────────────────────────
var questionResult = await embeddingClient.GenerateEmbeddingAsync(question);
float[] questionVector = questionResult.Value.ToFloats().ToArray();

// ── 6. Find the most similar document (cosine similarity) ────
var best = docEmbeddings
    .Select(d => (d.Text, Score: CosineSimilarity(questionVector, d.Vector)))
    .OrderByDescending(d => d.Score)
    .First();

Console.WriteLine($"Most relevant chunk (score {best.Score:F4}):");
Console.WriteLine($"  \"{best.Text}\"\n");

// ── 7. Send question + context to the chat model ─────────────
var chatResponse = await chatClient.CompleteChatAsync(new ChatMessage[]
{
    new SystemChatMessage(
        "Answer the user's question using ONLY the provided context. " +
        "If the context does not contain the answer, say you don't know."),
    new UserChatMessage(
        $"Context:\n{best.Text}\n\nQuestion:\n{question}")
});

Console.WriteLine("Answer:");
Console.WriteLine(chatResponse.Value.Content[0].Text);

// ── Helper: cosine similarity ────────────────────────────────
static float CosineSimilarity(float[] a, float[] b)
{
    float dot = 0, magA = 0, magB = 0;
    for (int i = 0; i < a.Length; i++)
    {
        dot  += a[i] * b[i];
        magA += a[i] * a[i];
        magB += b[i] * b[i];
    }
    return dot / (MathF.Sqrt(magA) * MathF.Sqrt(magB));
}