#include <cstdio>
#include <iostream>
#include <unordered_set>
#include <chrono>
#include "../include/FileUtil.hpp"
#include "../include/Conf.hpp"
#include "../include/Exec.hpp"
#include "../include/CmakeModule.hpp"
#include "../backend/BackendUtils.hpp"
#include "../backend/ninja/Ninja.hpp"

using namespace std;
using namespace sibs;
using namespace std::chrono;

// TODO: Fail if multiple versions of the same dependency is used
// as linking will fail because of multiple definitions of the same thing

// TODO: Detect circular dependencies

// TODO: Prevent infinite recursion in source file searching when there are symlinks.
// Either do not follow the symlinks or use a hash map with every searched directory
// to only go inside a directory once

// TODO: Places that use PATH_MAX should be modified. A path CAN be longer than PATH_MAX... (does this include replacing tinydir.h?)

// TODO: Remove install.sh when sibs supports installation of packages (so it can install itself)

// TODO: Move package tests, include_dirs and ignore_dirs under config in project.conf.
// Package object should only contain metadata for the package, which is used for finding dependencies
// and when building a list of installed packages / available packages.

// TODO: Allow different platforms to have different dependencies.
// This can be done by specifying dependencies under [dependencies.platform] instead of [dependencies],
// for example for win32: [dependencies.win32]

// TODO: When `package` command is added, the target executable and shared library dependencies should be put into
// an archive to make the executable distributable (especially on windows). A GUI installer could then extract the archive.
// On Linux we can use https://github.com/DEC05EBA/glibc_version_header to make the executable work on many distros
// without compiling project from source on the end-users machine.

// TODO: Add optional dependencies [optional_dependencies]. Optional dependencies should also support platform specific dependencies [dependencies.cmake].
// Might need to make it possible to define variables if a dependency exists (or doesn't exist) because the code might have
// preprocessor like: USE_LIBSODIUM or NO_LIBSODIUM.

// TODO: When building a sibs project, add a hardlink in ~/.cache/sibs/lib to it. This allows us to have dependency to a project that we can modify
// without having to commit & push to remote

// TODO: Check compiler flags generated by cmake and visual studio in debug and release mode and use the same ones when building sibs project.
// There are certain compiler flags we do not currently have, for example _ITERATOR_DEBUG_LEVEL in debug mode which enables runtime checks.
// You should be able to specify runtime checks as an option to `sibs build` and project specific config in .conf file.
// Also add stack protection option. If it's enabled, shouldn't sibs prefer to compile dependencies from source?
// and should this force static compilation so dependencies can also be built with protection and if dependencies dont exist
// as static library/source, then fail build?

// TODO: Add support for common package managers (in distros). If package with the dependency version exists in package manager, install and use it instead

// TODO: Make dependency/project names case insensitive. This means we can't use pkgconfig

// TODO: Fail build if dependency requires newer language version than dependant package.
// To make it work properly, should language version be required in project.conf?

// TODO: Remove duplicate compiler options (include flags, linker flags etc...) to improve compilation speed.
// The compiler ignores duplicate symbols but it's faster to just remove duplicate options because we only have
// to compare strings. Duplicate options can happen if for example a project has two dependencies and both dependencies
// have dependency on the same package (would be common for example with boost libraries or libraries that dpepend on boost)

// TODO: Create symlink to dependencies, for example if we have dependency on xxhash which has xxhash.h in its root directory,
// then you should be able to include it from dependant project by typing #include "xxhash/xxhash.h"
// that means we create a symlink with the dependency name to the dependency version directory.
// This will make it easier to prevent clashes in header file names and it's easier to see from the include statement
// what exactly we are including.

// TODO: Implement link-time-optimization which should be used if building with a certain optimization level (sibs build)

// TODO (bug): Fix issue where running sibs-build in a project that uses cmake wont build and run tests

// TODO: Add 'license' in project.conf. License must be commonly known license or 'custom'.
// This is to include lgpl dependencies as dynamic libraries and give error if you are using gpl dependencies in a non gpl project.
// If the license type is custom, then the ways the library can be used should be defined in such a way that dependent projects can determinate
// if the dependency can be used without breaking compatibility between licenses.
// License notice has to be in a file called LICENSE or COPYING in the root directory of the project and these files will be combined automatically
// for all dependencies when releasing your software, as including license with software is often required.
// TODO: Dynamically link libgit2 (sibs dependency) since it's under lgpl license. Optionally implement git clone/pull with MIT license.

// TODO: Auto export all symbols under windows (https://stackoverflow.com/questions/225432/export-all-symbols-when-creating-a-dll)

// TODO: Fix issue where when you have a dependency on a cmake project with dynamic library, the dynamic library wont be found at runtime for whatever reason

// TODO: Add program command for generating compile_commands.json without compiling code, without using Ninja

#if OS_FAMILY == OS_FAMILY_POSIX
#define ferr std::cerr
#else
#define ferr std::wcerr
#endif

void usage()
{
    printf("Usage: sibs COMMAND\n\n");
    printf("Simple Build System for Native Languages\n\n");
    printf("Commands:\n");
    printf("  build\t\tBuild a project that contains a project.conf file\n");
    printf("  new\t\tCreate a new project\n");
    printf("  test\t\tBuild and run tests for a sibs project\n");
    exit(1);
}

void usageBuild()
{
    printf("Usage: sibs build [project_path] [--debug|--release]\n\n");
    printf("Build a sibs project\n\n");
    printf("Options:\n");
    printf("  project_path\t\t The directory containing a project.conf file - Optional (default: current working directory)\n");
    printf("  --debug|--release\t\tOptimization level to build project and dependencies with (if not a system package) - Optional (default: --debug)\n");
    printf("Examples:\n");
    printf("  sibs build\n");
    printf("  sibs build dirA/dirB\n");
    printf("  sibs build --release\n");
    printf("  sibs build dirA --release\n");
    exit(1);
}

void usageNew()
{
    printf("Usage: sibs new <project_name> <--exec|--static|--dynamic>\n\n");
    printf("Create a new sibs project\n\n");
    printf("Options:\n");
    printf("  project_name\t\tThe name of the project you want to create\n");
    printf("  --exec\t\t\tProject compiles to an executable\n");
    printf("  --static\t\t\tProject compiles to a static library\n");
    printf("  --dynamic\t\t\tProject compiles to a dynamic library\n");
    printf("Examples:\n");
    printf("  sibs new hello_world --exec\n");
    exit(1);
}

void usageTest()
{
    printf("Usage: sibs test [project_path]\n\n");
    printf("Build and run tests for a sibs project\n\n");
    printf("Options:\n");
    printf("  project_path\t\t The directory containing a project.conf file - Optional (default: current working directory)\n");
    printf("Examples:\n");
    printf("  sibs test\n");
    printf("  sibs test dirA/dirB\n");
    exit(1);
}

void validateDirectoryPath(const _tinydir_char_t *projectPath)
{
    FileType projectPathFileType = getFileType(projectPath);
    if(projectPathFileType == FileType::FILE_NOT_FOUND)
    {
        string errMsg = "Invalid project path: ";
        errMsg += toUtf8(projectPath);
        perror(errMsg.c_str());
        exit(2);
    }
    else if(projectPathFileType == FileType::REGULAR)
    {
        ferr <<"Expected project path (" << projectPath << ") to be a directory, was a file" << endl;
        exit(3);
    }
}

void validateFilePath(const _tinydir_char_t *projectConfPath)
{
    FileType projectConfFileType = getFileType(projectConfPath);
    if(projectConfFileType == FileType::FILE_NOT_FOUND)
    {
        string errMsg = "Invalid project.conf path: ";
        errMsg += toUtf8(projectConfPath);
        perror(errMsg.c_str());
        exit(4);
    }
    else if(projectConfFileType == FileType::DIRECTORY)
    {
        ferr << "Expected project path (" << projectConfPath << ") to be a file, was a directory" << endl;
        exit(5);
    }
}

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

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

    return false;
}

bool isPathSubPathOf(const FileString &path, const FileString &subPathOf)
{
    return _tinydir_strncmp(path.c_str(), subPathOf.c_str(), subPathOf.size()) == 0;
}

int buildProject(const FileString &projectPath, const FileString &projectConfFilePath, SibsConfig &sibsConfig)
{
    FileString buildPath;
    readSibsConfig(projectPath, projectConfFilePath, sibsConfig, buildPath);
    // Test project has the main project as dependency, and therefore the main project can't be built as an executable
    if(sibsConfig.shouldBuildTests())
    {
        // 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.
        // It's ok if `define` fails. It could fail if `main` has already been replaced by other tests somehow.
        sibsConfig.define("main", "sibs_lib_ignore_main");
        sibsConfig.define("wmain", "sibs_lib_ignore_wmain");
        sibsConfig.setPackageType(PackageType::DYNAMIC);
    }

    auto startTime = high_resolution_clock::now();
    if(sibsConfig.shouldUseCmake())
    {
        auto dummyCallback = [](const string&){};
        
        // TODO: Add test and sub projects
        CmakeModule cmakeModule;
        Result<bool> cmakeCompileResult = cmakeModule.compile(sibsConfig, buildPath, dummyCallback, dummyCallback, dummyCallback);
        if(!cmakeCompileResult)
        {
            ferr << "Failed to compile using cmake: " << toFileString(cmakeCompileResult.getErrMsg()) << endl;
            exit(7);
        }
    }
    else
    {
        backend::Ninja ninja;
        // TODO: Do same for cmake
        switch (sibsConfig.getOptimizationLevel())
        {
            case OPT_LEV_DEBUG:
            {
                // TODO: Check if this dependency is static or dynamic and decide which lib path to use from that
                for(const string &staticLib : sibsConfig.getDebugStaticLibs())
                {
                    string staticLibCmd = "\"";
                    staticLibCmd += staticLib;
                    staticLibCmd += "\"";
                    ninja.addDependency(staticLibCmd);
                }
                break;
            }
            case OPT_LEV_RELEASE:
            {
                // TODO: Check if this dependency is static or dynamic and decide which lib path to use from that
                for (const string &staticLib : sibsConfig.getReleaseStaticLibs())
                {
                    string staticLibCmd = "\"";
                    staticLibCmd += staticLib;
                    staticLibCmd += "\"";
                    ninja.addDependency(staticLibCmd);
                }
                break;
            }
        }
        
        backend::BackendUtils::collectSourceFiles(projectPath.c_str(), &ninja, sibsConfig);
        sibsConfig.setMainProject(true);
        Result<bool> buildFileResult = ninja.build(sibsConfig, buildPath.c_str());
        if(buildFileResult.isErr())
        {
            ferr << "Failed to build ninja file: " << toFileString(buildFileResult.getErrMsg()) << endl;
            exit(7);
        }
    }
    auto elapsedTime = duration_cast<duration<double>>(high_resolution_clock::now() - startTime);
    printf("Finished in %fs\n", elapsedTime.count());

    return 0;
}

int buildProject(int argc, const _tinydir_char_t **argv)
{
    if(argc > 2)
        usageBuild();

    OptimizationLevel optimizationLevel = OPT_LEV_NONE;
    FileString projectPath;

    for(int i = 0; i < argc; ++i)
    {
        const _tinydir_char_t *arg = argv[i];
        if(_tinydir_strcmp(arg, TINYDIR_STRING("--debug")) == 0)
        {
            if(optimizationLevel != OPT_LEV_NONE)
            {
                ferr << "Error: Optimization level defined more than once. First defined as " << asString(optimizationLevel) << " then as debug" << endl;
                usageBuild();
            }
            optimizationLevel = OPT_LEV_DEBUG;
        }
        else if(_tinydir_strcmp(arg, TINYDIR_STRING("--release")) == 0)
        {
            if(optimizationLevel != OPT_LEV_NONE)
            {
                ferr << "Error: Optimization level defined more than once. First defined as " << asString(optimizationLevel) << " then as release" << endl;
                usageBuild();
            }
            optimizationLevel = OPT_LEV_RELEASE;
        }
        else
        {
            if(!projectPath.empty())
            {
                ferr << "Error: Project path was defined more than once. First defined as " << projectPath << " then as " << arg << endl;
                usageBuild();
            }
            projectPath = arg;
        }
    }

    if(optimizationLevel == OPT_LEV_NONE)
        optimizationLevel = OPT_LEV_DEBUG;

    // TODO: If projectPath is not defined and working directory does not contain project.conf, then search every parent directory until one is found
    if(projectPath.empty())
        projectPath = TINYDIR_STRING(".");

    validateDirectoryPath(projectPath.c_str());
    if(projectPath.back() != '/')
        projectPath += TINYDIR_STRING("/");

    Result<FileString> projectRealPathResult = getRealPath(projectPath.c_str());
    if(!projectRealPathResult)
    {
        ferr << "Failed to get real path for: '" << projectPath.c_str() << "': " << toFileString(projectRealPathResult.getErrMsg()) << endl;
        exit(40);
    }
    projectPath = projectRealPathResult.unwrap();

    FileString projectConfFilePath = projectPath;
    projectConfFilePath += TINYDIR_STRING("/project.conf");
    validateFilePath(projectConfFilePath.c_str());

    // TODO: Detect compiler to use at runtime. Should also be configurable
    // by passing argument to `sibs build`
#if OS_FAMILY == OS_FAMILY_POSIX
    Compiler compiler = Compiler::GCC;
#else
    Compiler compiler = Compiler::MSVC;
#endif

    SibsConfig sibsConfig(compiler, projectPath, optimizationLevel, false);
    return buildProject(projectPath, projectConfFilePath, sibsConfig);
}

int testProject(int argc, const _tinydir_char_t **argv)
{
    if(argc > 1)
        usageTest();

    FileString projectPath;
    if(argc == 1)
        projectPath = argv[0];
    
    // TODO: If projectPath is not defined and working directory does not contain project.conf, then search every parent directory until one is found
    if(projectPath.empty())
        projectPath = TINYDIR_STRING(".");

    validateDirectoryPath(projectPath.c_str());
    if(projectPath.back() != '/')
        projectPath += TINYDIR_STRING("/");

    Result<FileString> projectRealPathResult = getRealPath(projectPath.c_str());
    if(!projectRealPathResult)
    {
        ferr << "Failed to get real path for: '" << projectPath.c_str() << "': " << toFileString(projectRealPathResult.getErrMsg()) << endl;
        exit(40);
    }
    projectPath = projectRealPathResult.unwrap();

    FileString projectConfFilePath = projectPath;
    projectConfFilePath += TINYDIR_STRING("/project.conf");
    validateFilePath(projectConfFilePath.c_str());

    // TODO: Detect compiler to use at runtime. Should also be configurable
    // by passing argument to `sibs build`
#if OS_FAMILY == OS_FAMILY_POSIX
    Compiler compiler = Compiler::GCC;
#else
    Compiler compiler = Compiler::MSVC;
#endif

    SibsConfig sibsConfig(compiler, projectPath, OPT_LEV_DEBUG, true);
    return buildProject(projectPath, projectConfFilePath, sibsConfig);
}

void newProjectCreateMainDir(const FileString &projectPath)
{
    Result<bool> createProjectDirResult = createDirectoryRecursive(projectPath.c_str());
    if(createProjectDirResult.isErr())
    {
        ferr << "Failed to create project main directory: " << toFileString(createProjectDirResult.getErrMsg()) << endl;
        exit(20);
    }
}

void createProjectSubDir(const FileString &dir)
{
    Result<bool> createProjectDirResult = createDirectoryRecursive(dir.c_str());
    if(createProjectDirResult.isErr())
    {
        ferr << "Failed to create directory in project: " << toFileString(createProjectDirResult.getErrMsg()) << endl;
        exit(20);
    }
}

void createProjectFile(const FileString &projectFilePath, const string &fileContent)
{
    Result<bool> fileOverwriteResult = fileOverwrite(projectFilePath.c_str(), fileContent.c_str());
    if(fileOverwriteResult.isErr())
    {
        ferr << "Failed to create project file: " << toFileString(fileOverwriteResult.getErrMsg()) << endl;
        exit(20);
    }
}

void newProjectCreateConf(const string &projectName, const string &projectType, const FileString &projectPath)
{
    string projectConfStr = "[package]\n";
    projectConfStr += "name = \"" + projectName + "\"\n";
    projectConfStr += "type = \"" + projectType + "\"\n";
    projectConfStr += "version = \"0.1.0\"\n";
    projectConfStr += "platforms = [\"";
    projectConfStr += asString(SYSTEM_PLATFORM);
    projectConfStr += "\"]\n";
    projectConfStr += "tests = \"tests\"";
    projectConfStr += "\n\n";
    projectConfStr += "[dependencies]\n";
    
    FileString projectConfPath = projectPath;
    projectConfPath += TINYDIR_STRING("/project.conf");
    Result<bool> fileOverwriteResult = fileOverwrite(projectConfPath.c_str(), projectConfStr.c_str());
    if(fileOverwriteResult.isErr())
    {
        ferr << "Failed to create project.conf: " << toFileString(fileOverwriteResult.getErrMsg()) << endl;
        exit(20);
    }
}

// This can be replaced with createDirectory and fileOverwrite, but it's not important
// so there is no reason to do it (right now)
Result<ExecResult> gitInitProject(const FileString &projectPath)
{
    FileString cmd = TINYDIR_STRING("git init \"");
    cmd += projectPath;
    cmd += TINYDIR_STRING("\"");
    return exec(cmd.c_str());
}

int newProject(int argc, const _tinydir_char_t **argv)
{
    if(argc != 2)
    {
        ferr << "Expected 'new' command to be followed by two arguments - project name and type of project (--exec, --static or --dynamic)" << endl << endl;
        usageNew();
    }
    
    Result<FileString> cwdResult = getCwd();
    if(cwdResult.isErr())
    {
        ferr << "Failed to get current working directory: " << toFileString(cwdResult.getErrMsg()) << endl;
        exit(20);
    }

    string projectName = toUtf8(argv[0]);
    if(!isProjectNameValid(projectName))
    {
        ferr << "Project name can only contain alphanumerical characters, dash (-) or underscore (_)" << endl;
        exit(20);
    }
    
    FileString projectPath = cwdResult.unwrap();
    projectPath += TINYDIR_STRING("/");
    projectPath += toFileString(projectName);
    bool projectPathExists = getFileType(projectPath.c_str()) != FileType::FILE_NOT_FOUND;
    if(projectPathExists)
    {
        ferr << "Unable to create a new project at path '" << projectPath << "'. A file or directory already exists in the same location" << endl;
        exit(20);
    }

    const _tinydir_char_t *projectType = argv[1];

    string projectTypeConf;
    if(_tinydir_strcmp(projectType, TINYDIR_STRING("--exec")) == 0)
        projectTypeConf = "executable";
    else if(_tinydir_strcmp(projectType, TINYDIR_STRING("--static")) == 0)
        projectTypeConf = "static";
    else if(_tinydir_strcmp(projectType, TINYDIR_STRING("--dynamic")) == 0)
        projectTypeConf = "dynamic";
    else
    {
        ferr << "Expected project type to be either --exec, --static or --dynamic; was: " << projectType << endl << endl;
        usageNew();
    }
    
    newProjectCreateMainDir(projectPath);
    newProjectCreateConf(projectName, projectTypeConf, projectPath);
    createProjectSubDir(projectPath + TINYDIR_STRING("/src"));
    createProjectSubDir(projectPath + TINYDIR_STRING("/include"));
    createProjectSubDir(projectPath + TINYDIR_STRING("/tests"));
    if(projectTypeConf == "executable")
        createProjectFile(projectPath + TINYDIR_STRING("/src/main.cpp"), "#include <cstdio>\n\nint main(int argc, char **argv)\n{\n    printf(\"hello, world!\\n\");\n    return 0;\n}\n");
    // We are ignoring git init result on purpose. If it fails, just ignore it; not important
    gitInitProject(projectPath);
    return 0;
}

#if OS_FAMILY == OS_FAMILY_POSIX
int main(int argc, const _tinydir_char_t **argv)
#else
int wmain(int argc, const _tinydir_char_t **argv)
#endif
{
    unordered_map<string, string> param;
    unordered_set<string> flags;

    for(int i = 1; i < argc; ++i)
    {
        const _tinydir_char_t *arg = argv[i];
        int subCommandArgCount = argc - i - 1;
        const _tinydir_char_t **subCommandArgPtr = argv + i + 1;
        if(_tinydir_strcmp(arg, TINYDIR_STRING("build")) == 0)
        {
            return buildProject(subCommandArgCount, subCommandArgPtr);
        }
        else if(_tinydir_strcmp(arg, TINYDIR_STRING("new")) == 0)
        {
            return newProject(subCommandArgCount, subCommandArgPtr);
        }
        else if(_tinydir_strcmp(arg, TINYDIR_STRING("test")) == 0)
        {
            return testProject(subCommandArgCount, subCommandArgPtr);
        }
        else
        {
            ferr << "Expected command to be either 'build' or 'new', was: " << arg << endl << endl;
            usage();
        }
    }

    usage();
    return 0;
}