using System.Drawing;
using System.Windows.Forms;

namespace FastReport.Utils
{
    /// <summary>
    /// Storage service for forms.
    /// </summary>
    public class FormStorageService : ControlStorageService
    {
        private Form form;

        private const string key_Left = "Left";
        private const string key_Top = "Top";
        private const string key_Width = "Width";
        private const string key_Height = "Height";
        private const string key_Maximized = "Maximized";

        private bool IsVisibleOnAnyScreen(Rectangle rect)
        {
            Rectangle formRect = new Rectangle(rect.Left + 20, rect.Top + 20, rect.Width - 40, rect.Height - 40);
            foreach (Screen screen in Screen.AllScreens)
            {
                if (screen.WorkingArea.IntersectsWith(formRect))
                {
                    return true;
                }
            }
            return false;
        }

        /// <summary>
        /// Saves the form state to the configuration file.
        /// </summary>
        public void SaveFormState()
        {
            bool isMaximized = form.WindowState == FormWindowState.Maximized;
            bool isMinimized = form.WindowState == FormWindowState.Minimized;

            SetBool(key_Maximized, isMaximized);
            SetInt(key_Left, isMinimized ? 0 : form.Location.X);
            SetInt(key_Top, isMinimized ? 0 : form.Location.Y);
            SetInt(key_Width, form.Size.Width);
            SetInt(key_Height, form.Size.Height);
        }

        /// <summary>
        /// Restores the form state from the configuration file.
        /// </summary>
        public bool RestoreFormState(bool ignoreWindowState = false)
        {
            if (!Has(key_Left))
            {
                // there is no state information yet, display the form as it was designed (usually centered on screen).
                return true;
            }

            // Get current screen working area
            Rectangle screenWorkingArea = Screen.GetWorkingArea(form);
            int windowLeftPosition = screenWorkingArea.Left;
            int windowTopPosition = screenWorkingArea.Top;
            int windowWidth = screenWorkingArea.Width;
            int windowHeight = screenWorkingArea.Height;

            // Get saved left and top positions
            if (Has(key_Left) && Has(key_Top))
            {
                windowLeftPosition = GetInt(key_Left);
                windowTopPosition = GetInt(key_Top);
                form.Location = new Point(windowLeftPosition, windowTopPosition);
            }

            // Get saved width and height
            if (Has(key_Width) && Has(key_Height))
            {
                windowWidth = GetInt(key_Width);
                windowHeight = GetInt(key_Height);
                form.Size = new Size(windowWidth, windowHeight);
            }

            Rectangle formRect = new Rectangle(windowLeftPosition, windowTopPosition,
                windowWidth, windowHeight);

            // Check a visibility of form rectangle on any screen
            if (!IsVisibleOnAnyScreen(formRect))
            {
                form.StartPosition = FormStartPosition.WindowsDefaultLocation;
                form.Location = new Point(screenWorkingArea.Left, screenWorkingArea.Top);
            }

            form.StartPosition = FormStartPosition.Manual;

            // Set the window state
            if (!ignoreWindowState)
                form.WindowState = GetBool(key_Maximized) ?
                    FormWindowState.Maximized : FormWindowState.Normal;

            return GetBool(key_Maximized);
        }

        /// <summary>
        /// Gets font from font storage.
        /// </summary>
        /// <param name="formElement">Element name from font storage.</param>
        /// <param name="defaultFont">Default value.</param>
        /// <returns>The font object.</returns>
        public new Font GetFont(string formElement, Font defaultFont)
        {
            return base.GetFont(form.Name + "," + formElement, defaultFont);
        }

        /// <summary>
        /// Initializes a new instance of storage class.
        /// </summary>
        /// <param name="form">The form which state will be saved/restored.</param>
        public FormStorageService(Form form) : base(form, "Forms," + form.Name)
        {
            this.form = form;
        }
    }
}