using System.Text.Json;

namespace AxCopilot.Services.Agent;

/// <summary>MCP 서버의 리소스 목록을 조회합니다.</summary>
public class McpListResourcesTool : IAgentTool
{
    private readonly Func<IReadOnlyCollection<McpClientService>> _getClients;

    public McpListResourcesTool(Func<IReadOnlyCollection<McpClientService>> getClients)
    {
        _getClients = getClients;
    }

    public string Name => "mcp_list_resources";
    public string Description => "연결된 MCP 서버들의 리소스 목록을 조회합니다. server_name을 지정하면 특정 서버만 조회합니다.";
    public ToolParameterSchema Parameters => new()
    {
        Properties = new()
        {
            ["server_name"] = new ToolProperty
            {
                Type = "string",
                Description = "조회할 MCP 서버 이름. 생략하면 모든 연결된 서버를 조회합니다."
            }
        }
    };

    public async Task<ToolResult> ExecuteAsync(JsonElement args, AgentContext context, CancellationToken ct = default)
    {
        var serverName = args.ValueKind == JsonValueKind.Object &&
                         args.TryGetProperty("server_name", out var serverProp)
            ? serverProp.GetString() ?? ""
            : "";

        var clients = _getClients()
            .Where(c => c.IsConnected &&
                        (string.IsNullOrWhiteSpace(serverName) || string.Equals(c.ServerName, serverName, StringComparison.OrdinalIgnoreCase)))
            .ToList();

        if (clients.Count == 0)
            return ToolResult.Fail(string.IsNullOrWhiteSpace(serverName)
                ? "연결된 MCP 서버가 없습니다."
                : $"MCP 서버 '{serverName}'를 찾지 못했습니다.");

        var lines = new List<string>();
        foreach (var client in clients)
        {
            var resources = await client.ListResourcesAsync(ct);
            lines.Add($"[{client.ServerName}] {resources.Count}개 리소스");
            foreach (var resource in resources.Take(20))
            {
                var desc = string.IsNullOrWhiteSpace(resource.Description) ? "" : $" - {resource.Description}";
                var mime = string.IsNullOrWhiteSpace(resource.MimeType) ? "" : $" ({resource.MimeType})";
                lines.Add($"- {resource.Name} :: {resource.Uri}{mime}{desc}");
            }
        }

        return ToolResult.Ok(string.Join(Environment.NewLine, lines));
    }
}