#include <cstring>
#include "Ninja.hpp"
#include "../../include/FileUtil.hpp"
#include "../../include/Exec.hpp"
#include "../../include/PkgConfig.hpp"
#include "../../include/GlobalLib.hpp"

using namespace std;
using namespace sibs;

namespace backend
{
    string join(const vector<string> &list, const char *joinStr)
    {
        if(list.empty()) return "";
        string result;
        long stringSize = 0;
        long joinStrLen = strlen(joinStr);
        int i = 0;
        for(const string &str : list)
        {
            stringSize += str.size();
            if(!str.empty() && i > 0)
                stringSize += joinStrLen;
            ++i;
        }

        result.reserve(stringSize);

        i = 0;
        for(const string &str : list)
        {
            if(i > 0)
                result += joinStr;
            result += str;
            ++i;
        }

        return result;
    }
    
    Ninja::LibraryType getNinjaLibraryType(PackageType packageType)
    {
        switch(packageType)
        {
            case PackageType::EXECUTABLE:
                return Ninja::LibraryType::EXECUTABLE;
            case PackageType::STATIC:
                return Ninja::LibraryType::STATIC;
            case PackageType::DYNAMIC:
            case PackageType::LIBRARY:
                return Ninja::LibraryType::DYNAMIC;
        }
    }

    Ninja::Ninja()
    {

    }

    void Ninja::addSourceFile(const char *filepath)
    {
        string filePathStr = filepath ? filepath : "";
        if(filepath && !containsSourceFile(filePathStr))
        {
            sourceFiles.emplace_back(filePathStr);
            printf("Adding source file: %s\n", filepath);
        }
    }

    void Ninja::addTestSourceDir(const char *dir)
    {
        string dirStr = dir ? dir : "";
        if(dir && !containsTestSourceDir(dirStr))
        {
            testSourceDirs.emplace_back(dirStr);
            printf("Adding test source directory: %s\n", dir);
        }
    }

    void Ninja::addDependency(const std::string &binaryFile)
    {
        if(!containsDependency(binaryFile))
            binaryDependencies.emplace_back(binaryFile);
    }

    const std::vector<std::string>& Ninja::getSourceFiles() const
    {
        return sourceFiles;
    }

    bool Ninja::containsSourceFile(const string &filepath) const
    {
        for(const string &sourceFile : sourceFiles)
        {
            if(sourceFile == filepath)
                return true;
        }
        return false;
    }

    bool Ninja::containsTestSourceDir(const string &dir) const
    {
        for(const string &testSourceDir : testSourceDirs)
        {
            if(testSourceDir == dir)
                return true;
        }
        return false;
    }

    bool Ninja::containsDependency(const string &dependency) const
    {
        for(const string &binaryDependency : binaryDependencies)
        {
            if(binaryDependency == dependency)
                return true;
        }
        return false;
    }

    Result<bool> validatePkgConfigPackageVersionExists(const Dependency &dependency)
    {
        Result<bool> dependencyValidationResult = PkgConfig::validatePackageExists(dependency.name);
        if(dependencyValidationResult.isErr())
            return Result<bool>::Err(dependencyValidationResult.getErrMsg());

        Result<bool> dependencyVersionValidationResult = PkgConfig::validatePackageVersionAtLeast(dependency.name, dependency.version);
        if(dependencyVersionValidationResult.isErr())
            return Result<bool>::Err(dependencyVersionValidationResult.getErrMsg());

        return Result<bool>::Ok(true);
    }

    // TODO: First check if pkg-config is installed. If it's not, only check dependencies that exists in the dependencies sub directory.
    // If pkg-config is installed and dependency is not installed, check in dependencies sub directory.
    Result<bool> Ninja::getLinkerFlags(const SibsConfig &config, LinkerFlagCallbackFunc staticLinkerFlagCallbackFunc, LinkerFlagCallbackFunc dynamicLinkerFlagCallback) const
    {
        const vector<Dependency> &dependencies = config.getDependencies();
        if(dependencies.empty()) return Result<bool>::Ok(true);

        string globalLibDir = getHomeDir();
        globalLibDir += "/.sibs/lib";
        Result<bool> createGlobalLibDirResult = createDirectoryRecursive(globalLibDir.c_str());
        if(createGlobalLibDirResult.isErr())
            return createGlobalLibDirResult;

        vector<Dependency> pkgConfigDependencies;
        vector<Dependency> globalLibDependencies;
        for(const Dependency &dependency : dependencies)
        {
            Result<bool> pkgConfigDependencyValidation = validatePkgConfigPackageVersionExists(dependency);
            if(pkgConfigDependencyValidation.isOk())
            {
                pkgConfigDependencies.push_back(dependency);
            }
            else
            {
                globalLibDependencies.push_back(dependency);
            }
        }

        Result<string> pkgConfigLinkerFlagsResult = PkgConfig::getDynamicLibsLinkerFlags(pkgConfigDependencies);
        if(pkgConfigLinkerFlagsResult.isErr())
        {
            printf("%s, using global lib...\n", pkgConfigLinkerFlagsResult.getErrMsg().c_str());
            globalLibDependencies.reserve(globalLibDependencies.size() + pkgConfigDependencies.size());
            for(const Dependency &pkgConfigDependency : pkgConfigDependencies)
            {
                globalLibDependencies.push_back(pkgConfigDependency);
            }
            pkgConfigDependencies.clear();
        }
        else
        {
            if(!pkgConfigLinkerFlagsResult.unwrap().empty())
                dynamicLinkerFlagCallback(pkgConfigLinkerFlagsResult.unwrap());
        }

        for(const Dependency &globalLibDependency : globalLibDependencies)
        {
            printf("Dependency %s is missing from pkg-config, trying global lib\n", globalLibDependency.name.c_str());
            Result<string> globalLibLinkerFlagsResult = GlobalLib::getLibsLinkerFlags(config, globalLibDir, globalLibDependency.name, globalLibDependency.version, staticLinkerFlagCallbackFunc, dynamicLinkerFlagCallback);
            if(globalLibLinkerFlagsResult.isErr())
            {
                if(globalLibLinkerFlagsResult.getErrorCode() == GlobalLib::DependencyError::DEPENDENCY_NOT_FOUND || globalLibLinkerFlagsResult.getErrorCode() == GlobalLib::DependencyError::DEPENDENCY_VERSION_NO_MATCH)
                {
                    printf("Dependency not found in global lib, trying to download from github\n");
                    // TODO: Download several dependencies at the same time by adding them to a list
                    // and then iterate them and download them all using several threads.
                    // All dependecies should be downloaded at the same time, this includes dependencies of dependencies.
                    // If a dependency is missing, fail build BEFORE downloading dependencies and before compiling anything.
                    // You do not want to possibly wait several minutes only for build to fail when there is no compilation error.

                    // TODO: If return error is invalid url, then the message should be converted to
                    // invalid package name/version. A check should be done if it is the name or version
                    // that is invalid.
                    Result<bool> downloadDependencyResult = GlobalLib::downloadDependency(globalLibDependency);
                    if(downloadDependencyResult.isErr())
                        return downloadDependencyResult;

                    globalLibLinkerFlagsResult = GlobalLib::getLibsLinkerFlags(config, globalLibDir, globalLibDependency.name, globalLibDependency.version, staticLinkerFlagCallbackFunc, dynamicLinkerFlagCallback);
                    if(globalLibLinkerFlagsResult.isErr())
                        return Result<bool>::Err(globalLibLinkerFlagsResult);
                }
                else
                {
                    return Result<bool>::Err(globalLibLinkerFlagsResult);
                }
            }
        }

        return Result<bool>::Ok(true);
    }

    Result<bool> Ninja::build(const SibsConfig &config, const char *savePath, LinkerFlagCallbackFunc staticLinkerFlagCallbackFunc, LinkerFlagCallbackFunc dynamicLinkerFlagCallback)
    {
        // TODO: Do not quit here if no source files are provided. The source-less project could have dependencies
        if(sourceFiles.empty())
            return Result<bool>::Err("No source files provided");

        Result<bool> createBuildDirResult = createDirectoryRecursive(savePath);
        if(createBuildDirResult.isErr())
            return createBuildDirResult;
        
        LibraryType libraryType = getNinjaLibraryType(config.getPackageType());

        string ninjaBuildFilePath = savePath;
        ninjaBuildFilePath += "/build.ninja";

        string result;
        result.reserve(16384);

        string globalIncDir = getHomeDir();
        globalIncDir += "/.sibs/lib";

        result += "globalIncDir = '-I";
        result += globalIncDir;
        result += "'";
        for(const auto &includeDir : config.getIncludeDirs())
        {
            result += " '-I../../";
            result += includeDir;
            result += "'";
        }
        result += "\n\n";
        
        string defines;
        for(const auto &definePair : config.getDefines())
        {
            defines += " '-D";
            defines += definePair.first;
            defines += "=";
            defines += definePair.second;
            defines += "'";
        }
        
        if(!defines.empty())
            printf("Custom define: %s\n", defines.c_str());

        string buildJob;
        switch(libraryType)
        {
            case LibraryType::EXECUTABLE:
            {
                result += "rule cpp_COMPILER\n";
                result += "  command = ccache c++ $ARGS -c $in -o $out\n\n";

                result += "rule cpp_BUILD_EXEC\n";
                result += "  command = ccache c++ $ARGS -o $out $in $LINK_ARGS $aliasing\n\n";
                buildJob = "cpp_BUILD_EXEC";
                break;
            }
            case LibraryType::STATIC:
            {
                result += "rule cpp_COMPILER\n";
                result += "  command = ccache c++ $ARGS -c -fPIC $in -o $out\n\n";

                result += "rule cpp_BUILD_STATIC\n";
                result += "  command = ar rcs lib";
                result += config.getPackageName();
                result += ".a";
                result += " $in\n\n";
                buildJob = "cpp_BUILD_STATIC";
                break;
            }
            case LibraryType::DYNAMIC:
            {
                result += "rule cpp_COMPILER\n";
                result += "  command = ccache c++ $ARGS -c -fPIC $in -o $out\n\n";

                // --whole-archive
                result += "rule cpp_BUILD_DYNAMIC\n";
                result += "  command = ccache c++ $in -shared -o $out $LINK_ARGS $aliasing\n\n";
                buildJob = "cpp_BUILD_DYNAMIC";
                break;
            }
            default:
                assert(false);
                return Result<bool>::Err("Unexpected error");
        }

        string optimizationFlags;
        switch(config.getOptimizationLevel())
        {
            case OPT_LEV_DEBUG:
                optimizationFlags = "'-O0'";
                break;
            case OPT_LEV_RELEASE:
                optimizationFlags = "'-O3' '-DNDEBUG'";
                break;
        }

        vector<string> objectNames;
        objectNames.reserve(sourceFiles.size());
        for(const string &sourceFile : sourceFiles)
        {
            //string sourceFileEncoded = sourceFile;
            //replace(sourceFileEncoded, '/', '@');
            string objectName = config.getPackageName() + "@exe/" + sourceFile + ".o";
            result += "build ";
            result += objectName;
            result += ": cpp_COMPILER ../../";
            result += sourceFile;
            result += "\n";
            result += "  ARGS = $globalIncDir '-I" + config.getPackageName() + "@exe' '-I..' ";
            if(!defines.empty())
                result += defines;
            result += " '-fdiagnostics-color=always' '-pipe' '-D_FILE_OFFSET_BITS=64' '-Wall' '-Winvalid-pch' '-Wnon-virtual-dtor' " + optimizationFlags + " '-g'\n\n";
            objectNames.emplace_back(objectName);
        }

        // TODO: Allow configuring default linking flags. Maybe have `package.useThreads = false` to disable this flag
        string allLinkerFlags = "-pthread";

        // TODO: Somehow check loading order, because it has to be correct to work.. Or does it for dynamic libraries?
        // Anyways it's required for static libraries (especially on Windows)
        for(const string &binaryDependency : binaryDependencies)
        {
            allLinkerFlags += " ";
            allLinkerFlags += binaryDependency;
        }

        if(!staticLinkerFlagCallbackFunc || libraryType == LibraryType::DYNAMIC)
        {
            staticLinkerFlagCallbackFunc = [&allLinkerFlags](const string &linkerFlag)
            {
                allLinkerFlags += " ";
                allLinkerFlags += linkerFlag;
            };
        }

        // TODO: If project contains no source files, then we shouldn't override this function
        dynamicLinkerFlagCallback = [&allLinkerFlags](const string &linkerFlag)
        {
            allLinkerFlags += " ";
            allLinkerFlags += linkerFlag;
        };

        Result<bool> linkerFlags = getLinkerFlags(config, staticLinkerFlagCallbackFunc, dynamicLinkerFlagCallback);
        if(linkerFlags.isErr())
            return Result<bool>::Err(linkerFlags.getErrMsg());

        string projectGeneratedBinary = allLinkerFlags;
        projectGeneratedBinary += " '";
        projectGeneratedBinary += savePath;
        projectGeneratedBinary += "/";
        switch(libraryType)
        {
            case LibraryType::EXECUTABLE:
            {
                result += "build ";
                result += config.getPackageName();
                result += ": " + buildJob + " ";
                result += join(objectNames, " ");
                result += "\n";
                result += "  LINK_ARGS = '-Wl,--no-undefined,--as-needed' ";
                if(!allLinkerFlags.empty())
                {
                    result += allLinkerFlags;
                }
                result += "\n\n";
                projectGeneratedBinary += config.getPackageName();
                break;
            }
            case LibraryType::STATIC:
            {
                result += "build ";
                result += config.getPackageName();
                result += ": " + buildJob + " ";
                result += join(objectNames, " ");
                result += "\n\n";
                projectGeneratedBinary += config.getPackageName() + ".a";
                break;
            }
            case LibraryType::DYNAMIC:
            {
                result += "build lib";
                result += config.getPackageName();
                result += ".so: " + buildJob + " ";
                result += join(objectNames, " ");
                result += "\n";
                result += "  LINK_ARGS = '-Wl,--no-undefined,--as-needed' ";
                if(!allLinkerFlags.empty())
                {
                    result += allLinkerFlags;
                    //result += " '-Wl,--no-whole-archive'";
                }
                result += "\n\n";
                projectGeneratedBinary += "lib" + config.getPackageName() + ".so";
                break;
            }
            default:
                assert(false);
                return Result<bool>::Err("Unexpected error");
        }
        projectGeneratedBinary += "'";

        Result<bool> fileOverwriteResult = sibs::fileOverwrite(ninjaBuildFilePath.c_str(), sibs::StringView(result.data(), result.size()));
        if(fileOverwriteResult.isErr())
            return fileOverwriteResult;

        printf("Created ninja build file: %s\n", ninjaBuildFilePath.c_str());

        Result<bool> buildResult = build(savePath);
        if(!buildResult)
            return buildResult;

        Result<bool> buildTestResult = buildTests(projectGeneratedBinary, config, savePath);
        if(!buildTestResult)
            return buildTestResult;

        return Result<bool>::Ok(true);
    }

    const char *sourceFileExtensions[] = { "c", "cc", "cpp", "cxx" };
    bool isSourceFile(tinydir_file *file)
    {
        if(!file->is_reg)
            return false;

        for(const char *sourceFileExtension : sourceFileExtensions)
        {
            if(_tinydir_strcmp(sourceFileExtension, file->extension) == 0)
                return true;
        }

        return false;
    }

    Result<bool> Ninja::buildTests(const std::string &projectGeneratedBinary, const SibsConfig &config, const char *savePath)
    {
        if(testSourceDirs.empty())
            return Result<bool>::Ok(true);

        // Tests need parent project as dependency. Executables can't be included as dependency so we build it as dynamic library.
        // `build` also builds tests
        if(getNinjaLibraryType(config.getPackageType()) == LibraryType::EXECUTABLE)
        {
            SibsConfig parentProjConfigLib = config;
            parentProjConfigLib.setPackageType(PackageType::DYNAMIC);
            // HACK: We can build a package that is defined as executable and contains main function by redefining `main`
            // as something else.
            // TODO: Do not allow defining `main` in project.conf or as program argument to sibs (when sibs supports defines).
            // It's ok if `define` fails. It could fail if `main` has already been replaced by other tests somehow.
            parentProjConfigLib.define("main", "sibs_lib_ignore_main");
            return build(parentProjConfigLib, savePath, nullptr, nullptr);
        }

        for(const string &testSourceDir : testSourceDirs)
        {
            string projectConfFilePath = testSourceDir;
            projectConfFilePath += "/project.conf";

            FileType projectConfFileType = getFileType(projectConfFilePath.c_str());
            SibsTestConfig sibsTestConfig(testSourceDir);
            if(projectConfFileType == FileType::REGULAR)
            {
                Result<bool> result = Config::readFromFile(projectConfFilePath.c_str(), sibsTestConfig);
                if(!result)
                    return result;
            }

            backend::Ninja ninja;
            ninja.addDependency(projectGeneratedBinary);
            walkDirFilesRecursive(testSourceDir.c_str(), [&ninja, &sibsTestConfig](tinydir_file *file)
            {
                if (isSourceFile(file))
                {
                    ninja.addSourceFile(file->path + sibsTestConfig.getProjectPath().size() + 1);
                }
                else
                {
                    //printf("Ignoring non-source file: %s\n", file->path + projectPath.size());
                }
            });

            if(!ninja.getSourceFiles().empty())
            {
                string debugBuildPath = testSourceDir + "/sibs-build/debug";
                Result<bool> buildFileResult = ninja.build(sibsTestConfig, debugBuildPath.c_str());
                if (!buildFileResult)
                    return buildFileResult;

                Result<bool> buildResult = ninja.build(debugBuildPath.c_str());
                if (!buildResult)
                    return buildResult;
            }
        }

        return Result<bool>::Ok(true);
    }

    Result<bool> Ninja::build(const char *buildFilePath)
    {
        string command = "ninja -C '";
        command += buildFilePath;
        command += "'";
        Result<ExecResult> execResult = exec(command.c_str(), true);
        if(execResult.isOk())
        {
            if(execResult.unwrap().exitCode == 0)
                return Result<bool>::Ok(true);
            else
                return Result<bool>::Err(execResult.unwrap().execStdout);
        }
        else
            return Result<bool>::Err(execResult.getErrMsg());
    }
}