/*
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*/

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using UnityEngine;

namespace Paroxe.PdfRenderer
{
    public class PDFLibrary : IDisposable
    {

#if (UNITY_IOS || UNITY_WEBGL) && !UNITY_EDITOR
        public const string PLUGIN_ASSEMBLY = "__Internal";
#else
        public const string PLUGIN_ASSEMBLY = "pdfrenderer";
#endif

        public const string CurrentVersion = "3.0";

        public static System.Object nativeLock = new System.Object();

        public enum ErrorCode
        {
            ErrSuccess = 0, // No error.
            ErrUnknown = 1, // Unknown error.
            ErrFile = 2, // File not found or could not be opened.
            ErrFormat = 3, // File not in PDF format or corrupted.
            ErrPassword = 4, // Password required or incorrect password.
            ErrSecurity = 5, // Unsupported security scheme.
            ErrPage = 6 // Page not found or content error.
        }

        private static bool m_Disposed;
        private static PDFLibrary m_Instance;
        private static int m_RefCount;
        private bool m_IsInitialized;
        private static bool m_AlreadyDestroyed;

#if UNITY_WEBGL || !UNITY_EDITOR
        private static bool m_AlreadyInitialized;
#endif

        private PDFLibrary()
        {
#if UNITY_WEBGL && !UNITY_EDITOR
            if (!m_AlreadyInitialized)
            {
                PDFJS_InitLibrary();
                m_AlreadyInitialized = true;
            }
#else

#if !UNITY_EDITOR
			if (!m_AlreadyInitialized)
#endif
            {
                m_IsInitialized = true;
                m_AlreadyDestroyed = false;
                FPDF_InitLibrary(
                    "These binary file is intended to be used only by PDFRenderer plugin for Unity3D. http://paroxe.com/products/pdf-renderer/");
#if !UNITY_EDITOR
				m_AlreadyInitialized = true;
#endif
            }

#endif
        }

        ~PDFLibrary()
        {
            Dispose(false);
        }

        /// <summary>
        /// Return the last error code.
        /// </summary>
        /// <returns></returns>
        public static ErrorCode GetLastError()
        {
#if UNITY_WEBGL && !UNITY_EDITOR
            return ErrorCode.ErrSuccess;
#else
            Instance.EnsureInitialized();
            return (ErrorCode)FPDF_GetLastError();
#endif
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            lock (nativeLock)
            {
                if (!m_Disposed)
                {
                    if (m_RefCount == 0)
                    {
#if PDFRENDERER_DEBUG
                        PrintInstanceMap();
#endif

#if !UNITY_WEBGL || UNITY_EDITOR
                        if (!m_AlreadyDestroyed)
                        {
                            m_AlreadyDestroyed = true;
#if UNITY_EDITOR
                            FPDF_DestroyLibrary();
#endif
                        }
#endif

                        m_Disposed = true;
                        m_Instance = null;
                    }

                    m_Disposed = true;
                }
            }
        }

#if PDFRENDERER_DEBUG
        private static Dictionary<string, int> s_InstanceMap = new Dictionary<string, int>();

        private static void PrintInstanceMap()
        {
            foreach (string key in s_InstanceMap.Keys)
            {
                Debug.Log(key + " Count: " + s_InstanceMap[key]);
            }
        }
#endif

        internal static void AddRef(string token)
        {
            lock (nativeLock)
            {
#if PDFRENDERER_DEBUG
                if (s_InstanceMap.ContainsKey(token))
                    s_InstanceMap[token] = s_InstanceMap[token] + 1;
                else
                    s_InstanceMap.Add(token, 1);
#endif

                ++m_RefCount;
                Instance.EnsureInitialized();
            }
        }

        internal static void RemoveRef(string token)
        {
            lock (nativeLock)
            {
                --m_RefCount;

#if PDFRENDERER_DEBUG
                s_InstanceMap[token] = s_InstanceMap[token] - 1;
#endif
                if (m_RefCount == 0)
                {
                    if (m_Disposed)
                    {
#if PDFRENDERER_DEBUG
                        PrintInstanceMap();
#endif
#if !UNITY_WEBGL || UNITY_EDITOR
                        if (!m_AlreadyDestroyed)
                        {
                            m_AlreadyDestroyed = true;
                            FPDF_DestroyLibrary();
                        }
#endif

                        m_Instance = null;
                    }
                    else
                        m_Instance.Dispose();
                }
            }
        }

        public static PDFLibrary Instance
        {
            get
            {
                if (m_Instance == null)
                    m_Instance = new PDFLibrary();

                return m_Instance;
            }
        }

        public void EnsureInitialized()
        {

        }

        public bool IsInitialized
        {
            get
            {
                return m_IsInitialized;
            }
            set
            {
                m_IsInitialized = value;
            }
        }

        #region NATIVE

#if UNITY_WEBGL && !UNITY_EDITOR
        [DllImport(PLUGIN_ASSEMBLY)]
        private static extern void PDFJS_InitLibrary();
#else
        [DllImport(PLUGIN_ASSEMBLY)]
        private static extern uint FPDF_GetLastError();

        [DllImport(PLUGIN_ASSEMBLY)]
        private static extern void FPDF_DestroyLibrary();

        [DllImport(PLUGIN_ASSEMBLY, CharSet = CharSet.Ansi)]
        private static extern void FPDF_InitLibrary(string libSignature);
#endif

        #endregion
    }
}