#include "../include/Package.hpp"
#include "../include/curl.hpp"
#include "../external/rapidjson/error/en.h"

#ifdef GetObject
#undef GetObject
#endif

using namespace std;
using namespace rapidjson;

static Document *packageList = nullptr;

namespace sibs
{
    static vector<Platform> getPlatformsByNames(const vector<string> &platformNames)
    {
        vector<Platform> result;
        result.reserve(platformNames.size());
        for(const string &platformName : platformNames)
        {
            result.push_back(getPlatformByName(StringView(platformName.data(), platformName.size())));
        }
        return result;
    }

    static Result<PackageMetadata> getPackageMetadata(Value::ConstObject jsonObj)
    {
        const auto &description = jsonObj.FindMember("description");
        if(description == jsonObj.MemberEnd() || !description->value.IsString()) return Result<PackageMetadata>::Err("Expected description to be a string");
        const auto &version = jsonObj.FindMember("version");
        if(version == jsonObj.MemberEnd() || !version->value.IsString()) return Result<PackageMetadata>::Err("Expected version to be a string");
        const auto &platforms = jsonObj.FindMember("platforms");
        if(platforms == jsonObj.MemberEnd() || !platforms->value.IsArray() || platforms->value.GetArray().Empty()) return Result<PackageMetadata>::Err("Expected platforms to be an array of strings");
        const auto &urls = jsonObj.FindMember("urls");
        if(urls == jsonObj.MemberEnd() || !urls->value.IsArray() || urls->value.GetArray().Empty()) return Result<PackageMetadata>::Err("Expected urls to be an array of string");
        
        PackageMetadata packageMetadata;
        packageMetadata.description.assign(description->value.GetString(), description->value.GetStringLength());
        packageMetadata.version.assign(version->value.GetString(), version->value.GetStringLength());
        
        const auto &platformsArray = platforms->value.GetArray();
        packageMetadata.platforms.reserve(platformsArray.Size());
        for(int i = 0; i < platformsArray.Size(); ++i)
        {
            const auto &platformElement = platformsArray[i];
            if(!platformElement.IsString())
                return Result<PackageMetadata>::Err("Expected platforms to only contain strings");
            packageMetadata.platforms.push_back(platformElement.GetString());
        }
        
        const auto &urlsArray = urls->value.GetArray();
        packageMetadata.urls.reserve(urlsArray.Size());
        for(int i = 0; i < urlsArray.Size(); ++i)
        {
            const auto &urlElement = urlsArray[i];
            if(!urlElement.IsString())
                return Result<PackageMetadata>::Err("Expected urls to only contain strings");
            packageMetadata.urls.push_back(urlElement.GetString());
        }
        
        return Result<PackageMetadata>::Ok(packageMetadata);
    }
    
    static Result<string> getPackageUrl(const PackageMetadata &packageMetadata, const char *packageName, const char *packageVersion, Platform platform)
    {
        if(strcmp(packageMetadata.version.c_str(), packageVersion) != 0)
        {
            string errMsg = "Package \"";
            errMsg += packageName;
            errMsg += "\" does not exist for version \"";
            errMsg += packageVersion;
            errMsg += "\"";
            return Result<string>::Err(errMsg);
        }
        
        if(!containsPlatform(getPlatformsByNames(packageMetadata.platforms), platform))
        {
            string errMsg = "Package \"";
            errMsg += packageName;
            errMsg += "\" with version \"";
            errMsg += packageVersion;
            errMsg += "\" does not support platform \"";
            errMsg += platform;
            errMsg += "\"";
            return Result<string>::Err(errMsg);
        }
        
        return Result<string>::Ok(packageMetadata.urls[0]);
    }
    
    // TODO: Always downloading is fine right now because the package list is small. This should later be modified to use local cache.
    // The package file should be stored locally (at ~/.cache/sibs/packages.json) and the version file should also be stored.
    // First we check if the version is incorrect and if it, we download the new packages.json file.
    // We should only check if the package list is up to date once every 10 minute or so (make it configurable in a config file?)
    // to improve build performance and reduce server load.
    // Or maybe we dont have to do that at all....
    Result<Document*> Package::getPackageList(const char *url)
    {
        if(packageList)
            return Result<Document*>::Ok(packageList);
        
        HttpResult httpResult = curl::get(url);
        if(!httpResult.success)
            return Result<Document*>::Err(httpResult.str, httpResult.httpCode);
        
        Document *doc = new Document();
        ParseResult parseResult = doc->Parse(httpResult.str.c_str());
        if(!parseResult)
        {
            string errMsg = "Failed to parse package list json file: ";
            errMsg += GetParseError_En(parseResult.Code());
            errMsg += " (";
            errMsg += to_string(parseResult.Offset());
            errMsg += ")";
            return Result<Document*>::Err(errMsg);
        }
        
        packageList = doc;
        return Result<Document*>::Ok(packageList);
    }
    
    Result<string> Package::getPackageUrl(const char *packageName, const char *packageVersion, Platform platform)
    {
        Result<Document*> packageList = Package::getPackageList("https://gitlab.com/DEC05EBA/sibs_packages/raw/master/packages.json");
        if(!packageList)
            return Result<string>::Err(packageList);
        
        const Document &packageDoc = *packageList.unwrap();
        
		auto packageMetaDataJsonIt = packageDoc.FindMember(packageName);
		if (packageMetaDataJsonIt == packageDoc.MemberEnd())
		{
			string errMsg = "No package with the name \"";
			errMsg += packageName;
			errMsg += "\" was found";
			return Result<string>::Err(errMsg);
		}

        if(packageMetaDataJsonIt->value.IsObject())
        {
            Result<PackageMetadata> packageMetadataResult = getPackageMetadata(packageMetaDataJsonIt->value.GetObject());
            if(!packageMetadataResult) return Result<string>::Err(packageMetadataResult);
            return ::sibs::getPackageUrl(packageMetadataResult.unwrap(), packageName, packageVersion, platform);
        }
        else if(packageMetaDataJsonIt->value.IsArray())
        {
            int i = 0;
            for(const auto &packageData : packageMetaDataJsonIt->value.GetArray())
            {
                if(!packageData.IsObject())
                {
                    string errMsg = "Package file is corrupt. ";
                    errMsg += packageName;
                    errMsg += "[";
                    errMsg += to_string(i);
                    errMsg += "] is not an object";
                    return Result<string>::Err(errMsg);
                }
                
                Result<PackageMetadata> packageMetadataResult = getPackageMetadata(packageData.GetObject());
                if(packageMetadataResult)
                {
                    Result<string> packageUrlResult = ::sibs::getPackageUrl(packageMetadataResult.unwrap(), packageName, packageVersion, platform);
                    if(packageUrlResult)
                        return packageUrlResult;
                }
            
                ++i;
            }
            
            string errMsg = "Package \"";
            errMsg += packageName;
            errMsg += "\" with version \"";
            errMsg += packageVersion;
            errMsg += "\" does not exist or does not exist for platform \"";
            errMsg += platform;
            errMsg += "\"";
            return Result<string>::Err(errMsg);
        }
        else
        {
            string errMsg = "No package with the name \"";
            errMsg += packageName;
            errMsg += "\" was found";
            return Result<string>::Err(errMsg);
        }
    }
}