<?php

namespace Cli\Commands;

use Cli\Services\EnvironmentLoader;
use Cli\Services\ProgramRunner;
use Minicli\Command\CommandCall;

class InitCommand
{
    /**
     * @throws CommandError
     */
    public function handle(CommandCall $input)
    {
        echo "Checking system requirements...\n";
        $this->ensureRequirementsMet();

        $suggestedOutPath = $input->subcommand;
        if ($suggestedOutPath === 'default') {
            $suggestedOutPath = '';
        }

        echo "Locating and checking install directory...\n";
        $installDir = $this->getInstallDir($suggestedOutPath);
        $this->ensureInstallDirEmptyAndWritable($installDir);

        echo "Cloning down BookStack project to install directory...\n";
        $this->cloneBookStackViaGit($installDir);

        echo "Checking composer exists...\n";
        $composer = $this->getComposerProgram($installDir);
        try {
            $composer->ensureFound();
        } catch (\Exception $exception) {
            echo "Composer does not exist, downloading a local copy...\n";
            $this->downloadComposerToInstall($installDir);
        }

        echo "Installing application dependencies using composer...\n";
        $this->installComposerDependencies($composer, $installDir);

        echo "Creating .env file from .env.example...\n";
        copy($installDir . DIRECTORY_SEPARATOR . '.env.example', $installDir . DIRECTORY_SEPARATOR . '.env');
        sleep(1);

        echo "Generating app key...\n";
        $this->generateAppKey($installDir);

        // Announce end
        echo "A BookStack install has been initialized at: {$installDir}\n\n";
        echo "You will still need to:\n";
        echo "- Update the .env file in the install with correct URL, database and email details.\n";
        echo "- Run 'php artisan migrate' to set-up the database.\n";
        echo "- Configure your webserver for use with BookStack.\n";
        echo "- Ensure the required directories (storage/ bootstrap/cache public/uploads) are web-server writable.\n";
    }

    /**
     * Ensure the required PHP extensions are installed for this command.
     * @throws CommandError
     */
    protected function ensureRequirementsMet(): void
    {
        $errors = [];

        if (version_compare(PHP_VERSION, '8.0.2') < 0) {
            $errors[] = "PHP >= 8.0.2 is required to install BookStack.";
        }

        $requiredExtensions = ['bcmath', 'curl', 'gd', 'iconv', 'libxml', 'mbstring', 'mysqlnd', 'xml'];
        foreach ($requiredExtensions as $extension) {
            if (!extension_loaded($extension)) {
                $errors[] = "The \"{$extension}\" PHP extension is required by not active.";
            }
        }

        try {
            (new ProgramRunner('git', '/usr/bin/git'))->ensureFound();
            (new ProgramRunner('php', '/usr/bin/php'))->ensureFound();
        } catch (\Exception $exception) {
            $errors[] = $exception->getMessage();
        }

        if (count($errors) > 0) {
            throw new CommandError("Requirements failed with following errors:\n" . implode("\n", $errors));
        }
    }

    protected function downloadComposerToInstall(string $installDir): void
    {
        $setupPath = $installDir . DIRECTORY_SEPARATOR . 'composer-setup.php';
        $signature = file_get_contents('https://composer.github.io/installer.sig');
        copy('https://getcomposer.org/installer', $setupPath);
        $checksum = hash_file('sha384', $setupPath);

        if ($signature !== $checksum) {
            unlink($setupPath);
            throw new CommandError("Could not install composer, checksum validation failed.");
        }

        $status = (new ProgramRunner('php', '/usr/bin/php'))
            ->runWithoutOutputCallbacks([
                $setupPath, '--quiet',
                "--install-dir={$installDir}",
                "--filename=composer",
            ]);

        unlink($setupPath);

        if ($status !== 0) {
            throw new CommandError("Could not install composer, composer-setup script run failed.");
        }
    }

    /**
     * Get the composer program.
     */
    protected function getComposerProgram(string $installDir): ProgramRunner
    {
        return (new ProgramRunner('composer', '/usr/local/bin/composer'))
            ->withTimeout(300)
            ->withIdleTimeout(15)
            ->withAdditionalPathLocation($installDir);
    }

    protected function generateAppKey(string $installDir): void
    {
        $errors = (new ProgramRunner('php', '/usr/bin/php'))
            ->withTimeout(60)
            ->withIdleTimeout(5)
            ->withEnvironment(EnvironmentLoader::load($installDir))
            ->runCapturingAllOutput([
                $installDir . DIRECTORY_SEPARATOR . 'artisan',
                'key:generate', '--force', '-n', '-q'
            ]);

        if ($errors) {
            throw new CommandError("Failed 'php artisan key:generate' with errors:\n" . $errors);
        }
    }

    /**
     * Run composer install to download PHP dependencies.
     * @throws CommandError
     */
    protected function installComposerDependencies(ProgramRunner $composer, string $installDir): void
    {
        $errors = $composer->runCapturingStdErr([
                'install',
                '--no-dev', '-n', '-q', '--no-progress',
                '-d', $installDir
            ]);

        if ($errors) {
            throw new CommandError("Failed composer install with errors:\n" . $errors);
        }
    }

    /**
     * Clone a new instance of BookStack to the given install folder.
     * @throws CommandError
     */
    protected function cloneBookStackViaGit(string $installDir): void
    {
        $errors = (new ProgramRunner('git', '/usr/bin/git'))
            ->withTimeout(240)
            ->withIdleTimeout(15)
            ->runCapturingStdErr([
                'clone', '-q',
                '--branch', 'release',
                '--single-branch',
                'https://github.com/BookStackApp/BookStack.git',
                $installDir
            ]);

        if ($errors) {
            throw new CommandError("Failed git clone with errors:\n" . $errors);
        }
    }

    /**
     * Ensure that the installation directory is completely empty to avoid potential conflicts or issues.
     * @throws CommandError
     */
    protected function ensureInstallDirEmptyAndWritable(string $installDir): void
    {
        $contents = array_diff(scandir($installDir), ['..', '.']);
        if (count($contents) > 0) {
            throw new CommandError("Expected install directory to be empty but existing files found in [{$installDir}] target location.");
        }

        if (!is_writable($installDir)) {
            throw new CommandError("Target install directory [{$installDir}] is not writable.");
        }
    }

    /**
     * Build a full path to the intended location for the BookStack install.
     * @throws CommandError
     */
    protected function getInstallDir(string $suggestedDir): string
    {
        $dir = getcwd();

        if ($suggestedDir) {
            if (is_file($suggestedDir)) {
                throw new CommandError("Was provided [{$suggestedDir}] as an install path but existing file provided.");
            } else if (is_dir($suggestedDir)) {
                $dir = realpath($suggestedDir);
            } else if (is_dir(dirname($suggestedDir))) {
                $created = mkdir($suggestedDir);
                if (!$created) {
                    throw new CommandError("Could not create directory [{$suggestedDir}] for install.");
                }
                $dir = realpath($suggestedDir);
            } else {
                throw new CommandError("Could not resolve provided [{$suggestedDir}] path to an existing folder.");
            }
        }

        return $dir;
    }
}