#pragma once

#include "types.hpp"
#include "StringView.hpp"
#include "utils.hpp"
#include <boost/filesystem/path.hpp>
#include <string>
#include <unordered_map>
#include <thread>
#include <mutex>
#include <vector>
#include <chrono>
#include <functional>

namespace TinyProcessLib
{
    class Process;
}

namespace dchat
{
    class Gif;
    class StaticImage;
    class WebPagePreview;
    
    struct ContentByUrlResult
    {
        enum class Type
        {
            CACHED,
            DOWNLOADING,
            FAILED_DOWNLOAD
        };
        
        enum class CachedType
        {
            NONE,
            STATIC_IMAGE,
            GIF,
            WEB_PAGE_PREVIEW
        };
        
        ContentByUrlResult() : staticImage(nullptr), type(Type::DOWNLOADING), cachedType(CachedType::NONE) {}
        ContentByUrlResult(StaticImage *_staticImage, Type _type) : staticImage(_staticImage), type(_type), cachedType(CachedType::STATIC_IMAGE) {}
        ContentByUrlResult(Gif *_gif, Type _type) : gif(_gif), type(_type), cachedType(CachedType::GIF) {}
        ContentByUrlResult(WebPagePreview *_webPagePreview, Type _type) : webPagePreview(_webPagePreview), type(_type), cachedType(CachedType::WEB_PAGE_PREVIEW) {}
        
        // @texture is null if @type is DOWNLOADING or FAILED_DOWNLOAD
        union
        {
            StaticImage *staticImage;
            Gif *gif;
            WebPagePreview *webPagePreview;
        };
        
        Type type;
        CachedType cachedType;
        i64 lastAccessed;
    };

    // @fileContent contains data allocated with new[], deallocate it with delete[] fileContent.data;
    // Returned gif should be allocated with @new
    using CreateGifFunc = std::function<Gif*(StringView fileContent)>;
    using CreateStaticImageFunc = std::function<StaticImage*(const boost::filesystem::path &filepath)>;
    using CreateWebPagePreviewFunc = std::function<WebPagePreview*(const std::string &title, const std::string &description)>;

    class Cache
    {
        DISABLE_COPY(Cache)
    public:
        // @createGifFunc can't be null
        // @createStaticImageFunc can't be null
        // @createWebPagePreviewFunc can't be null
        Cache(CreateGifFunc createGifFunc, CreateStaticImageFunc createStaticImageFunc, CreateWebPagePreviewFunc createWebPagePreviewFunc);
        ~Cache();
        
        // Get cached content or download it. 
        // Default download file limit is 12MB
        // Returns ContentByUrlResult describing texture status.
        const ContentByUrlResult getContentByUrl(const std::string &url, int downloadLimitBytes = 12582912);
    private:
        ContentByUrlResult loadImageFromFile(const boost::filesystem::path &filepath, bool loadFromCache);
    private:
        struct ImageDownloadInfo
        {
            TinyProcessLib::Process *process;
            std::string url;
        };
        
        std::thread downloadWaitThread;
        std::thread checkContentAccessTimeThread;
        std::vector<ImageDownloadInfo> imageDownloadProcesses;
        std::vector<ImageDownloadInfo> imageDownloadProcessesQueue;
        std::mutex imageDownloadMutex;
        bool alive;
        std::unordered_map<std::string, ContentByUrlResult> contentUrlCache;
        CreateGifFunc createGifFunc;
        CreateStaticImageFunc createStaticImageFunc;
        CreateWebPagePreviewFunc createWebPagePreviewFunc;
    };
}