using System.IO;
using System.Linq;
using System.Text.Json;

namespace AxCopilot.Services.Agent;

public sealed class TaskUpdateTool : IAgentTool
{
    public string Name => "task_update";

    public string Description =>
        "Update task fields (status/title/description/priority) in the workspace task board.";

    public ToolParameterSchema Parameters => new()
    {
        Properties = new()
        {
            ["id"] = new() { Type = "integer", Description = "Task id" },
            ["status"] = new() { Type = "string", Description = "open | in_progress | blocked | done | stopped" },
            ["title"] = new() { Type = "string", Description = "New title (optional)" },
            ["description"] = new() { Type = "string", Description = "New description (optional)" },
            ["priority"] = new() { Type = "string", Description = "high | medium | low" },
        },
        Required = ["id"]
    };

    public Task<ToolResult> ExecuteAsync(JsonElement args, AgentContext context, CancellationToken ct = default)
    {
        if (!args.TryGetProperty("id", out var idEl))
            return Task.FromResult(ToolResult.Fail("id is required."));
        if (string.IsNullOrWhiteSpace(context.WorkFolder) || !Directory.Exists(context.WorkFolder))
            return Task.FromResult(ToolResult.Fail("valid WorkFolder is required."));

        var id = idEl.GetInt32();
        var tasks = TaskBoardStore.Load(context.WorkFolder);
        var task = tasks.FirstOrDefault(t => t.Id == id);
        if (task == null)
            return Task.FromResult(ToolResult.Fail($"Task #{id} not found."));

        if (args.TryGetProperty("status", out var statusEl))
        {
            var status = (statusEl.GetString() ?? "").Trim().ToLowerInvariant();
            if (!TaskBoardStore.IsValidStatus(status))
                return Task.FromResult(ToolResult.Fail("Invalid status."));
            task.Status = status;
        }

        if (args.TryGetProperty("title", out var titleEl))
        {
            var title = (titleEl.GetString() ?? "").Trim();
            if (!string.IsNullOrWhiteSpace(title))
                task.Title = title;
        }

        if (args.TryGetProperty("description", out var descEl))
            task.Description = (descEl.GetString() ?? "").Trim();

        if (args.TryGetProperty("priority", out var priEl))
        {
            var priority = (priEl.GetString() ?? "").Trim().ToLowerInvariant();
            if (!TaskBoardStore.IsValidPriority(priority))
                return Task.FromResult(ToolResult.Fail("Invalid priority."));
            task.Priority = priority;
        }

        task.UpdatedAt = DateTime.Now;
        TaskBoardStore.Save(context.WorkFolder, tasks);
        return Task.FromResult(ToolResult.Ok($"Updated task #{task.Id}: [{task.Status}] {task.Title}"));
    }
}