using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace WebCam
{
    class WebCamFeed
    {
        #region Constants

        private const int WS_CHILD = 0x40000000;
        private const int WS_VISIBLE = 0x10000000;
        private const int WM_CAP_DRIVER_CONNECT = WM_USER + 10;
        private const int WM_CAP_DRIVER_DISCONNECT = WM_USER + 11;
        private const int WM_CAP_SET_PREVIEW = WM_USER + 50;
        private const int WM_CAP_SET_PREVIEWRATE = WM_USER + 52;

        private const short WM_USER = 0x0400;

        private const long WM_CAP_SEQUENCE = WM_USER + 62;

        #endregion

        #region API Declaration

        [DllImport("user32.dll", EntryPoint = "SendMessageA")]
        static extern int SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam);

        [DllImport("avicap32.dll", EntryPoint = "capCreateCaptureWindowA")]
        static extern int capCreateCaptureWindow(string lpszWindowName, int dwStyle, int x, int y, int nWidth,
            int nHeight,
            IntPtr hWndParent,
            int nID);

        [DllImport("avicap32.dll", EntryPoint = "capGetDriverDescriptionA")]
        static extern int capGetDriverDescription(int wDriverIndex, string lpszName, int cbName, string lpszVer,
            int cbVer);

        #endregion

        #region Variables

        private Boolean isRunning = false;

        private String devName = "";

        private int hWndC;
        private int outputHeight = 274;
        private int outputWidth = 235;
        private int frameRate = 29;

        #endregion

        public WebCamFeed()
        {
            //Do nothing!
        }

        public void initCam(IntPtr hWndParent)
        {
            if (isRunning == false)
            {
                //Create a capture window
                this.hWndC = capCreateCaptureWindow(devName, WS_CHILD | WS_VISIBLE, 0, 0, outputHeight, outputWidth, hWndParent,0);
            }
            else
            {
                MessageBox.Show("The camera is already running", "Camera Error", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            //Start the camera
            if (startCam(hWndParent) == false)
            {
                MessageBox.Show("Unable to initialise camera", "Camera Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            }
        }

        //Partial code taken from Pino's iCam Class
        public Boolean startCam(IntPtr hWndParent)
        {
            //Try to connect the camera driver
            if (SendMessage(hWndParent, WM_CAP_DRIVER_CONNECT, 0, 0) == 1)
            {
                //Start video preview
                SendMessage(hWndParent, WM_CAP_SET_PREVIEWRATE, frameRate, 0);
                SendMessage(hWndParent, WM_CAP_SET_PREVIEW, 1, 0);
                //Camera is running
                this.isRunning = true;
                //Return true (indicating that the camera did start)
                return true;
            }
            else
            {
                this.isRunning = false;
                //Return false (indicating that the camera didn't start)
                return false;
            }
        }

        public void resetCam(IntPtr hWndParent)
        {
            //Close camera
            stopCam(hWndParent);
            //Start camera again
            initCam(hWndParent);
        }

        public Boolean stopCam(IntPtr hWndParent)
        {
            //Stop the camera
            if (SendMessage(hWndParent, WM_CAP_DRIVER_DISCONNECT, 0, 0) == 1)
            {
                //Camera is now not running
                this.isRunning = false;
                //Return true (indicating that the camera did stop)
                return true;
            }
            else
            {
                //Give the user an error message
                MessageBox.Show("Unable to stop camera", "Camera Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                //Return false (indicating that the camera didn't stop)
                return false;
            }
        }

        public int getFPS()
        {
            //Return the FPS
            return (1000 / frameRate);
        }

        public Boolean getIsRunning()
        {
            //Return 'isRunning'
            return isRunning;
        }
    }
}