using System;
using System.Text;
using UnityEngine;
using UnityEngine.UI;

namespace Aisu.SIM1.Face.Samples.FaceDetectionDemo
{
    /// <summary>
    /// MVP 操作日志窗口。
    /// </summary>
    public sealed class FaceDetectionDemoLogger : MonoBehaviour
    {
        [SerializeField] private Text m_logText;             // 日志文本。
        [SerializeField] private ScrollRect m_scrollRect;    // 日志滚动视图。

        private readonly StringBuilder m_buffer = new StringBuilder(8192); // 日志缓存。

        /// <summary>
        /// 绑定 UI。
        /// </summary>
        public void Bind(Text logText, ScrollRect scrollRect)
        {
            m_logText = logText;
            m_scrollRect = scrollRect;
        }

        /// <summary>
        /// 写入普通日志。
        /// </summary>
        public void Info(string message)
        {
            Append("INFO", message);
        }

        /// <summary>
        /// 写入错误日志。
        /// </summary>
        public void Error(string message)
        {
            Append("ERROR", message);
        }

        /// <summary>
        /// 清空日志。
        /// </summary>
        public void Clear()
        {
            m_buffer.Length = 0;
            Refresh();
        }

        private void Append(string level, string message)
        {
            m_buffer.Append('[')
                .Append(DateTime.Now.ToString("HH:mm:ss"))
                .Append("] ")
                .Append(level)
                .Append("  ")
                .AppendLine(message ?? string.Empty);
            Refresh();
        }

        private void Refresh()
        {
            if (m_logText != null)
            {
                m_logText.text = m_buffer.ToString();
            }

            if (m_scrollRect != null)
            {
                Canvas.ForceUpdateCanvases();
                m_scrollRect.verticalNormalizedPosition = 0f;
            }
        }
    }
}