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

using namespace std;
using namespace sibs;

// 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)

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

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

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;
}

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

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

    OptimizationLevel optimizationLevel = OPT_LEV_NONE;
    string projectPath;

    for(int i = 0; i < argc; ++i)
    {
        const char *arg = argv[i];
        if(strcmp(arg, "--debug") == 0)
        {
            if(optimizationLevel != OPT_LEV_NONE)
            {
                fprintf(stderr, "Error: Optimization level defined more than once. First defined as %s then as %s\n", asString(optimizationLevel), "debug");
                usageBuild();
            }
            optimizationLevel = OPT_LEV_DEBUG;
        }
        else if(strcmp(arg, "--release") == 0)
        {
            if(optimizationLevel != OPT_LEV_NONE)
            {
                fprintf(stderr, "Error: Optimization level defined more than once. First defined as %s then as %s\n", asString(optimizationLevel), "debug");
                usageBuild();
            }
            optimizationLevel = OPT_LEV_RELEASE;
        }
        else
        {
            if(!projectPath.empty())
            {
                fprintf(stderr, "Error: Project path was defined more than once. First defined as %s then as %s\n", projectPath.c_str(), arg);
                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 = ".";

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

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

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

    SibsConfig sibsConfig(projectPath, optimizationLevel);
    Result<bool> result = Config::readFromFile(projectConfFilePath.c_str(), sibsConfig);
    if(result.isErr())
    {
        cerr << "Failed to read config: " << result.getErrMsg() << endl;
        exit(6);
    }

    if(sibsConfig.getPackageName().empty())
    {
        cerr << "project.conf is missing required field package.name" << endl;
        exit(10);
    }

    //string projectSrcPath = projectPath + "/src";
    //validateDirectoryPath(projectSrcPath.c_str());

    PackageType packageType = sibsConfig.getPackageType();
    backend::Ninja::LibraryType libraryType;
    switch(packageType)
    {
        case PackageType::EXECUTABLE:
            libraryType = backend::Ninja::LibraryType::EXECUTABLE;
            break;
        case PackageType::STATIC:
            libraryType = backend::Ninja::LibraryType::STATIC;
            break;
        case PackageType::DYNAMIC:
        case PackageType::LIBRARY:
            libraryType = backend::Ninja::LibraryType::DYNAMIC;
            break;
    }

    backend::Ninja ninja(libraryType);
    FileWalkCallbackFunc collectSourceFiles = [&ninja, &sibsConfig, &collectSourceFiles](tinydir_file *file)
    {
        if(file->is_reg)
        {
            if (isSourceFile(file))
            {
                ninja.addSourceFile(file->path + sibsConfig.getProjectPath().size());
            }
            else
            {
                //printf("Ignoring non-source file: %s\n", file->path + projectPath.size());
            }
        }
        else
        {
            // TODO: If compiling without "test" option, do not add test source dir to ninja. Ninja logic will then not build tests
            if(!sibsConfig.getTestPath().empty() && isPathSubPathOf(file->path, sibsConfig.getTestPath()))
                ninja.addTestSourceDir(file->path);
            else
                walkDir(file->path, collectSourceFiles);
        }
    };
    walkDir(projectPath.c_str(), collectSourceFiles);

    string buildPath = projectPath + "/sibs-build/";
    switch(sibsConfig.getOptimizationLevel())
    {
        case OPT_LEV_DEBUG:
            buildPath += "debug";
            break;
        case OPT_LEV_RELEASE:
            buildPath += "release";
            break;
    }

    Result<bool> buildFileResult = ninja.build(sibsConfig, buildPath.c_str());
    if(buildFileResult.isErr())
    {
        cerr << "Failed to build ninja file: " << buildFileResult.getErrMsg() << endl;
        exit(7);
    }

    return 0;
}

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

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

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

void newProjectCreateConf(const string &projectName, const string &projectType, const string &projectPath)
{
    string projectConfStr = "[package]\n";
    projectConfStr += "name = \"" + projectName + "\"\n";
    projectConfStr += "type = \"" + projectType + "\"\n";
    projectConfStr += "version = \"0.1.0\"\n\n";
    projectConfStr += "[dependencies]\n";
    
    string projectConfPath = projectPath;
    projectConfPath += "/project.conf";
    Result<bool> fileOverwriteResult = fileOverwrite(projectConfPath.c_str(), projectConfStr.c_str());
    if(fileOverwriteResult.isErr())
    {
        cerr << "Failed to create project.conf: " << 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 string &projectPath)
{
    string cmd = "git init '";
    cmd += projectPath;
    cmd += "'";
    return exec(cmd.c_str());
}

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

    string projectName = argv[0];
    string projectPath = cwdResult.unwrap();
    projectPath += "/";
    projectPath += projectName;
    bool projectPathExists = getFileType(projectPath.c_str()) != FileType::FILE_NOT_FOUND;
    if(projectPathExists)
    {
        cerr << "Unable to create a new project at path '" << projectPath << "'. A file or directory already exists in the same location" << endl;
        exit(20);
    }

    const char *projectType = argv[1];

    string projectTypeConf;
    if(strcmp(projectType, "--exec") == 0)
        projectTypeConf = "executable";
    else if(strcmp(projectType, "--static") == 0)
        projectTypeConf = "static";
    else if(strcmp(projectType, "--dynamic") == 0)
        projectTypeConf = "dynamic";
    else
    {
        cerr << "Expected project type to be either --exec, --static or --dynamic; was: " << projectType << endl << endl;
        usageNew();
    }
    
    newProjectCreateMainDir(projectPath);
    newProjectCreateConf(projectName, projectTypeConf, projectPath);
    createProjectSubDir(projectPath + "/src");
    createProjectSubDir(projectPath + "/include");
    createProjectFile(projectPath + "/src/main.cpp", "#include <cstdio>\n\nint main()\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;
}

int main(int argc, const char **argv)
{
    unordered_map<string, string> param;
    unordered_set<string> flags;

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

    usage();
    return 0;
}