using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json.Linq;
using SwarmUI.Accounts;
using SwarmUI.Utils;

namespace Mrleo1nid.SwarmAssistent;

/// <summary>VRAM handover between Ollama and the image backend: park the chat model before
/// Generate, warm it again once the user is back in the chat. Embed / memory models are never
/// parked — they are tiny and reloading them stalls every retrieve.
/// Warm is a no-op when Ollama already has the chat model resident (/api/ps) so post-Generate
/// reload is cheap when Krea did not evict VL.</summary>
public partial class SwarmAssistentExtension
{
    const string WarmKeepAlive = "15m";

    /// <summary>Unloads the chat model from VRAM (<c>keep_alive: 0</c>) so Krea 2 gets the whole GPU.</summary>
    public async Task<JObject> AssistentParkLlm(Session session, string baseUrl, string model)
    {
        string root = NormalizeBaseUrl(baseUrl);
        string name = (model ?? "").Trim();
        if (string.IsNullOrWhiteSpace(name))
        {
            return new JObject { ["error"] = "model is required" };
        }
        if (LooksLikeEmbedModel(name))
        {
            return new JObject { ["success"] = true, ["parked"] = false, ["skipped"] = "memory model — never parked" };
        }
        // Already unloaded — skip the keep_alive:0 round-trip.
        if (!await IsOllamaModelResident(root, name))
        {
            return new JObject
            {
                ["success"] = true,
                ["parked"] = false,
                ["skipped"] = "not_resident",
                ["model"] = name,
                ["base_url"] = root,
            };
        }
        JObject generate = new()
        {
            ["model"] = name,
            ["prompt"] = "",
            ["stream"] = false,
            ["keep_alive"] = 0,
        };
        (bool ok, string body) = await PostOllamaJson(root, "/api/generate", generate);
        if (!ok)
        {
            // Older Ollama builds only unload through /api/chat.
            JObject chat = new()
            {
                ["model"] = name,
                ["messages"] = new JArray(),
                ["stream"] = false,
                ["keep_alive"] = 0,
            };
            (ok, body) = await PostOllamaJson(root, "/api/chat", chat);
        }
        if (!ok)
        {
            Logs.Debug($"AssistentParkLlm {name}: {Clip(body, 200)}");
            return new JObject { ["success"] = true, ["parked"] = false, ["note"] = Clip(body, 200) };
        }
        return new JObject { ["success"] = true, ["parked"] = true, ["model"] = name, ["base_url"] = root };
    }

    /// <summary>Single-token chat so the model is resident again by the time the user types.
    /// Skips the load when /api/ps already lists the model (avoids ~20–30s no-op warm).</summary>
    public async Task<JObject> AssistentWarmLlm(Session session, string baseUrl, string model)
    {
        string root = NormalizeBaseUrl(baseUrl);
        string name = (model ?? "").Trim();
        if (string.IsNullOrWhiteSpace(name))
        {
            return new JObject { ["error"] = "model is required" };
        }
        if (LooksLikeEmbedModel(name))
        {
            return new JObject { ["success"] = true, ["warmed"] = false, ["skipped"] = "memory model" };
        }
        if (await IsOllamaModelResident(root, name))
        {
            return new JObject
            {
                ["success"] = true,
                ["warmed"] = true,
                ["skipped"] = "already_resident",
                ["model"] = name,
                ["keep_alive"] = WarmKeepAlive,
            };
        }
        int numCtx = CfgInt("num_ctx", DefaultNumCtxFallback);
        JObject payload = new()
        {
            ["model"] = name,
            ["stream"] = false,
            ["messages"] = new JArray
            {
                new JObject { ["role"] = "user", ["content"] = "ok" },
            },
            ["options"] = new JObject
            {
                ["num_ctx"] = numCtx,
                ["num_predict"] = 1,
            },
            ["keep_alive"] = WarmKeepAlive,
        };
        (bool ok, string body) = await PostOllamaJson(root, "/api/chat", payload);
        if (!ok)
        {
            Logs.Debug($"AssistentWarmLlm {name}: {Clip(body, 200)}");
            return new JObject { ["success"] = true, ["warmed"] = false, ["note"] = Clip(body, 200) };
        }
        return new JObject
        {
            ["success"] = true,
            ["warmed"] = true,
            ["model"] = name,
            ["num_ctx"] = numCtx,
            ["keep_alive"] = WarmKeepAlive,
        };
    }

    /// <summary>True when Ollama /api/ps lists <paramref name="model"/> (or a matching tag).</summary>
    async Task<bool> IsOllamaModelResident(string root, string model)
    {
        if (string.IsNullOrWhiteSpace(root) || string.IsNullOrWhiteSpace(model))
        {
            return false;
        }
        try
        {
            using HttpResponseMessage resp = await HttpClient.GetAsync($"{root}/api/ps");
            if (!resp.IsSuccessStatusCode)
            {
                return false;
            }
            string body = await resp.Content.ReadAsStringAsync();
            JObject parsed = JObject.Parse(body);
            JArray models = parsed["models"] as JArray ?? [];
            foreach (JToken m in models)
            {
                string name = m["name"]?.ToString() ?? m["model"]?.ToString() ?? "";
                if (string.IsNullOrWhiteSpace(name))
                {
                    continue;
                }
                if (string.Equals(name, model, StringComparison.OrdinalIgnoreCase))
                {
                    return true;
                }
                // Tags may differ by :latest vs bare name.
                if (name.StartsWith(model + ":", StringComparison.OrdinalIgnoreCase)
                    || model.StartsWith(name + ":", StringComparison.OrdinalIgnoreCase))
                {
                    return true;
                }
            }
            return false;
        }
        catch (Exception ex)
        {
            Logs.Debug($"IsOllamaModelResident: {ex.Message}");
            return false;
        }
    }

    static async Task<(bool ok, string body)> PostOllamaJson(string root, string route, JObject payload)
    {
        try
        {
            using StringContent content = new(payload.ToString(Newtonsoft.Json.Formatting.None), Encoding.UTF8, "application/json");
            using HttpResponseMessage resp = await HttpClient.PostAsync($"{root}{route}", content);
            string body = await resp.Content.ReadAsStringAsync();
            return (resp.IsSuccessStatusCode, body);
        }
        catch (Exception ex)
        {
            return (false, ex.Message);
        }
    }
}