using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Windows.Forms;

namespace Dongke.WinForm.Controls.InvoiceLayout
{
    internal partial class BackgroundSetting : Setting
    {
        #region 成员变量
        private Image _backgroundImage = null;                            // 背景图片
        private LayoutBox _layoutBox = null;                                // LayoutBox
        #endregion

        #region 属性
        /// <summary>
        /// 背景图片文件全名
        /// </summary>
        public string BackgroundImageName
        {
            get
            {
                return txtBackgroundName.Text;
            }
        }

        /// <summary>
        /// 背景图片
        /// </summary>
        public new Image BackgroundImage
        {
            get
            {
                return _backgroundImage;
            }
        }

        /// <summary>
        /// LayoutBox
        /// </summary>
        public LayoutBox LayoutBox
        {
            get
            {
                return _layoutBox;
            }
        }
        #endregion 属性

        #region 构造函数
        /// <summary>
        /// 构造函数
        /// </summary>
        public BackgroundSetting(LayoutBox layoutBox)
        {
            _layoutBox = layoutBox;
            InitializeComponent();

            // 获取背景图片名称，不为空时设置删除按钮的状态为可用
            if (!string.IsNullOrEmpty(layoutBox.BackgroundImageName))
            {
                btnRemove.Enabled = true;
                txtBackgroundName.Text = layoutBox.BackgroundImageName;
            }

            // 打开选择图片的对话框
            openFileDialog.Title = this.Text;
            openFileDialog.Filter = LayoutConsts.FILE_DIALOG_IMAGE_FILTER;
            openFileDialog.FilterIndex = 6;
            string directory = Environment.GetFolderPath(Environment.SpecialFolder.MyPictures);
            if (Directory.Exists(directory))
            {
                openFileDialog.InitialDirectory = directory;
            }
            else
            {
                openFileDialog.InitialDirectory =
                    Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            }

            // 图片另存为时，保存图片对话框
            saveFileDialog.Title = Text;
            saveFileDialog.FileName = _layoutBox.BackgroundImageName;
            saveFileDialog.Filter = LayoutConsts.FILE_DIALOG_IMAGE_FILTER;
            saveFileDialog.FilterIndex = 6;
            if (Directory.Exists(directory))
            {
                saveFileDialog.InitialDirectory = directory;
            }
            else
            {
                saveFileDialog.InitialDirectory =
                    Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            }
        }
        #endregion 构造函数

        #region 函数
        /// <summary>
        /// 压缩图片为jpeg
        /// </summary>
        /// <param name="image">压缩前的图片</param>
        /// <param name="qualityValue">图片品质。例：25L</param>
        /// <param name="newImage">压缩后的jpeg图片</param>
        /// <param name="newSize">压缩后的图片大小</param>
        /// <returns>是否压缩成功</returns>
        private static bool ConvertToJpegImage(Image image, long qualityValue, out Image newImage, out long newSize)
        {
            newImage = null;
            newSize = 0;

            ImageCodecInfo jpegCodecInfo = null;
            ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
            for (int i = 0; i < encoders.Length; i++)
            {
                if (encoders[i].MimeType.Equals("image/jpeg"))
                {
                    jpegCodecInfo = encoders[i];
                    break;
                }
            }
            if (jpegCodecInfo == null)
            {
                MessageBox.Show("图片转换失败，请手动调整图像。",
                                "图片转换",
                                MessageBoxButtons.OK,
                                MessageBoxIcon.Error,
                                MessageBoxDefaultButton.Button1);
                return false;
            }

            Encoder ecoderParamQuality = Encoder.Quality;
            EncoderParameters encoderParams = new EncoderParameters(1);
            encoderParams.Param[0] = new EncoderParameter(ecoderParamQuality, qualityValue);

            // Save
            try
            {
                MemoryStream mstream = new MemoryStream();
                image.Save(mstream, jpegCodecInfo, encoderParams);
                newImage = Image.FromStream(mstream);
                newSize = mstream.Length;
                return true;
            }
            catch(Exception)
            {
                MessageBox.Show("图片转换失败，请手动调整图像。",
                                "图片转换",
                                MessageBoxButtons.OK,
                                MessageBoxIcon.Error,
                                MessageBoxDefaultButton.Button1);
                return false;
            }
        }

        /// <summary>
        /// 获得图片的尺寸。单位：byte
        /// </summary>
        /// <param name="image">图片</param>
        /// <returns>图片的尺寸。单位：byte</returns>
        private static long GetImageSize(Image image)
        {
            if (image == null)
            {
                return 0;
            }

            long size = 0;
            try
            {
                using (MemoryStream mstream = new MemoryStream())
                {
                    image.Save(mstream, image.RawFormat);
                    size = mstream.Length;
                }
                return size;
            }
            catch
            {
                return 0;
            }
        }

        /// <summary>
        /// 显示图片尺寸
        /// </summary>
        private void RefreshImageSizeLabel(Image image)
        {
            long size = GetImageSize(image);
            RefreshImageSizeLabel(size);
        }

        /// <summary>
        /// 显示图片尺寸
        /// </summary>
        /// <param name="size"></param>
        private void RefreshImageSizeLabel(long size)
        {
            if (0 < size)
            {
                lblImageSize.Text = string.Format("{0:N0}Kbyte", size / 1024);
            }
            else
            {
                lblImageSize.Text = string.Empty;
            }
        }

        /// <summary>
        /// 按钮可用状态设置。
        /// </summary>
        private void SetButtonState()
        {
            // 另存为
            btnSaveAs.Enabled = (_layoutBox.BackgroundImage != null);
            // 图片压缩
            btnCompress.Enabled = (_layoutBox.BackgroundImage != null || _backgroundImage != null);
            // 删除
            btnRemove.Enabled = (_layoutBox.BackgroundImage != null || _backgroundImage != null);

            // 确定
            btnOK.Enabled = true;
            // 取消
            btnCancel.Enabled = true;
        }
        #endregion 函数

        #region 事件处理
        /// <summary>
        /// Load
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void BackgroundSetting_Load(object sender, EventArgs e)
        {
            RefreshImageSizeLabel(_layoutBox.BackgroundImage);
            SetButtonState();
        }

        /// <summary>
        /// 【删除】按钮点击
        /// </summary>
        /// <param name="sender">指定的对象</param>
        /// <param name="e">提供的事件数据</param>
        private void btnRemove_Click(object sender, System.EventArgs e)
        {
            DialogResult dr = MessageBox.Show("是否删除背景图片？",
                                                Text,
                                                MessageBoxButtons.YesNo,
                                                MessageBoxIcon.Question,
                                                MessageBoxDefaultButton.Button1);
            if (dr == DialogResult.Yes)
            {
                _backgroundImage = null;
                txtBackgroundName.Text = string.Empty;
                DialogResult = DialogResult.OK;
                Close();
            }
        }

        /// <summary>
        /// 【选择】按钮点击
        /// </summary>
        /// <param name="sender">指定的对象</param>
        /// <param name="e">提供的事件数据</param>
        private void btnReference_Click(object sender, System.EventArgs e)
        {
            try
            {
                if (openFileDialog.ShowDialog() == DialogResult.OK)
                {
                    FileInfo fileInfo = new FileInfo(openFileDialog.FileName);

                    Image image = null;

                    if (fileInfo.Length > 0)
                    {
                        Stream imageStream = null;
                        try
                        {
                            imageStream = fileInfo.Open(FileMode.Open,
                                                        FileAccess.Read,
                                                        FileShare.ReadWrite | FileShare.Delete);
                            image = Image.FromStream(imageStream);

                            MemoryStream mstream = new MemoryStream();
                            image.Save(mstream, image.RawFormat);
                            image = Image.FromStream(mstream);

                            RefreshImageSizeLabel(mstream.Length);

                            if (LayoutConsts.FILE_DIALOG_IMAGE_MAX_SIZE < mstream.Length)
                            {
                                DialogResult dr = MessageBox.Show(
                                            string.Format("图片的尺寸为{0}，超过200Kbyte，是否对图片进行压缩？", lblImageSize.Text)
                                            + Environment.NewLine
                                            + Environment.NewLine
                                            + "※通常图片大小在100K字节以下足够了，大尺寸的图片会降低屏幕显示和打印的速度。",
                                            Text,
                                            MessageBoxButtons.YesNo,
                                            MessageBoxIcon.Question,
                                            MessageBoxDefaultButton.Button1);

                                if (dr == DialogResult.Yes)
                                {
                                    Image newImage;
                                    long newSize;
                                    ConvertToJpegImage(image, LayoutConsts.QUALITY_VALUE, out newImage, out newSize);

                                    image.Dispose();
                                    image = null;
                                    image = newImage;
                                    RefreshImageSizeLabel(newSize);
                                }
                            }
                            else
                            {
                            }
                        }
                        finally
                        {
                            if (imageStream != null)
                            {
                                imageStream.Dispose();
                            }
                        }
                    }
                    else
                    {
                        MessageBox.Show("图片的大小为零，不能设置。",
                                        Text,
                                        MessageBoxButtons.OK,
                                        MessageBoxIcon.Error,
                                        MessageBoxDefaultButton.Button1);
                        return;
                    }
                    txtBackgroundName.Text = Path.GetFileName(openFileDialog.FileName);
                    if (_backgroundImage != null)
                    {
                        _backgroundImage.Dispose();
                    }
                    _backgroundImage = image;
                }
            }
            finally
            {
                SetButtonState();
            }
        }

        /// <summary>
        /// 【确定】按钮点击
        /// </summary>
        /// <param name="sender">指定的对象</param>
        /// <param name="e">提供的事件数据</param>
        private void btnOK_Click(object sender, EventArgs e)
        {
            if (_backgroundImage != null)
            {
                DialogResult = DialogResult.OK;
            }
            else
            {
                DialogResult = DialogResult.Cancel;
            }
            Close();
        }

        /// <summary>
        /// 【另存为】按钮点击
        /// </summary>
        /// <param name="sender">指定的对象</param>
        /// <param name="e">提供的事件数据</param>
        private void btnSaveAs_Click(object sender, EventArgs e)
        {
            if (_layoutBox.BackgroundImage == null || string.IsNullOrEmpty(_layoutBox.BackgroundImageName))
            {
                return;
            }

            saveFileDialog.FileName = _layoutBox.BackgroundImageName;
            if (DialogResult.OK != saveFileDialog.ShowDialog())
            {
                return;
            }

            using (Image image = (Image)_layoutBox.BackgroundImage.Clone())
            {
                image.Save(saveFileDialog.FileName);
            }
        }

        /// <summary>
        /// 【压缩图片】按钮点击
        /// </summary>
        /// <param name="sender">指定的对象</param>
        /// <param name="e">提供的事件数据</param>
        private void btnCompress_Click(object sender, EventArgs e)
        {
            Image target = null;
            if (_backgroundImage != null)
            {
                target = _backgroundImage;
            }
            else if (_layoutBox.BackgroundImage != null)
            {
                target = _layoutBox.BackgroundImage;
            }
            else
            {
                return;
            }

            long orgSize = GetImageSize(target);

            Image newImage;
            long newSize;

            ConvertToJpegImage(target, LayoutConsts.QUALITY_VALUE, out newImage, out newSize);
            if (newImage == null)
            {
                return;
            }
            if (orgSize < newSize)
            {
                if (newImage != null)
                {
                    newImage.Dispose();
                    newImage = null;
                }
                MessageBox.Show("背景图片压缩失败。",
                                Text,
                                MessageBoxButtons.OK,
                                MessageBoxIcon.Information,
                                MessageBoxDefaultButton.Button1);
                return;
            }

            if (_backgroundImage != null)
            {
                _backgroundImage.Dispose();
            }
            _backgroundImage = newImage;

            RefreshImageSizeLabel(newSize);

            MessageBox.Show("背景图片压缩完成。",
                            Text,
                            MessageBoxButtons.OK,
                            MessageBoxIcon.Information,
                            MessageBoxDefaultButton.Button1);
        }
        #endregion 事件处理
    }
}