using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Json;
using System.Text.Json;
using System.Threading.Tasks;
using System.Text.Json.Serialization;
using System.Linq;

namespace finder2e_foundry_converter.Services
{
    public class OllamaService : ILlmService
    {
        private readonly HttpClient _httpClient = new HttpClient();

        public async Task<List<string>> GetModelsAsync(string baseUrl)
        {
            try
            {
                var response = await _httpClient.GetFromJsonAsync<OllamaModelsResponse>($"{baseUrl.TrimEnd('/')}/api/tags");
                if (response?.Models == null) return new List<string>();

                return response.Models.Select(m => m.Name).ToList();
            }
            catch
            {
                return new List<string> { "Error: Ollama not found" };
            }
        }

        public async Task<string> GenerateResponseAsync(string baseUrl, string model, string text, List<string> imagePaths)
        {
            try
            {
                var images = new List<string>();
                foreach (var path in imagePaths)
                {
                    if (string.IsNullOrWhiteSpace(path)) continue;
                    var bytes = await System.IO.File.ReadAllBytesAsync(path);
                    images.Add(Convert.ToBase64String(bytes));
                }

                var requestBody = new
                {
                    model = model,
                    messages = new[]
                    {
                        new { role = "user", content = text, images = images.Count > 0 ? images.ToArray() : null }
                    },
                    stream = false
                };

                var response = await _httpClient.PostAsJsonAsync($"{baseUrl.TrimEnd('/')}/api/chat", requestBody);
                var body = await response.Content.ReadAsStringAsync();

                using var doc = JsonDocument.Parse(body);
                if (doc.RootElement.TryGetProperty("error", out var error))
                {
                    return $"Error: {error.GetString()}";
                }

                if (doc.RootElement.TryGetProperty("message", out var message))
                {
                    return message.GetProperty("content").GetString() ?? "No content returned";
                }

                return "No response returned.";
            }
            catch (Exception ex)
            {
                return $"Error: {ex.Message}";
            }
        }

        public async Task<string> AskAsync(string baseUrl, string model, string prompt, List<string> imagePaths)
        {
            // Reuse GenerateResponseAsync semantics for single-shot prompts
            return await GenerateResponseAsync(baseUrl, model, prompt, imagePaths);
        }

        private class OllamaModelsResponse
        {
            [JsonPropertyName("models")]
            public List<OllamaModelData>? Models { get; set; }
        }

        private class OllamaModelData
        {
            [JsonPropertyName("name")]
            public string Name { get; set; } = string.Empty;
        }
    }
}