<?php
declare(strict_types=1);

namespace Fendx\CLI;

use Fendx\CLI\Command\CommandInterface;
use Fendx\CLI\Input\InputInterface;
use Fendx\CLI\Input\ArgvInput;
use Fendx\CLI\Output\OutputInterface;
use Fendx\CLI\Output\ConsoleOutput;
use Fendx\CLI\Exception\CommandNotFoundException;

final class Application
{
    private string $name;
    private string $version;
    private array $commands = [];
    private bool $autoExit = true;
    private ?CommandInterface $runningCommand = null;

    public function __construct(string $name = 'FendxCLI', string $version = '1.0.0')
    {
        $this->name = $name;
        $this->version = $version;
    }

    public function run(?InputInterface $input = null, ?OutputInterface $output = null): int
    {
        $input = $input ?? new ArgvInput();
        $output = $output ?? new ConsoleOutput();

        try {
            $exitCode = $this->doRun($input, $output);
        } catch (\Exception $e) {
            $this->renderException($e, $output);
            $exitCode = 1;
        }

        if ($this->autoExit) {
            exit($exitCode);
        }

        return $exitCode;
    }

    private function doRun(InputInterface $input, OutputInterface $output): int
    {
        // 处理全局选项
        if ($input->hasParameterOption(['--help', '-h'])) {
            $this->showHelp($output);
            return 0;
        }

        if ($input->hasParameterOption(['--version', '-v'])) {
            $this->showVersion($output);
            return 0;
        }

        // 获取命令名称
        $commandName = $input->getFirstArgument();
        
        if ($commandName === null) {
            $this->showHelp($output);
            return 0;
        }

        // 查找命令
        $command = $this->findCommand($commandName);
        $this->runningCommand = $command;

        // 设置输入
        $input->bind($command->getDefinition());

        // 验证输入
        $input->validate();

        // 执行命令
        $exitCode = $command->run($input, $output);

        return $exitCode;
    }

    public function add(CommandInterface $command): self
    {
        $command->setApplication($this);
        $this->commands[$command->getName()] = $command;

        // 添加别名
        foreach ($command->getAliases() as $alias) {
            $this->commands[$alias] = $command;
        }

        return $this;
    }

    public function get(string $name): CommandInterface
    {
        if (!isset($this->commands[$name])) {
            throw new CommandNotFoundException(sprintf('Command "%s" does not exist.', $name));
        }

        return $this->commands[$name];
    }

    public function has(string $name): bool
    {
        return isset($this->commands[$name]);
    }

    public function all(): array
    {
        return $this->commands;
    }

    public function find(string $name): CommandInterface
    {
        if (!$this->has($name)) {
            // 尝试模糊匹配
            $alternatives = $this->findAlternatives($name, array_keys($this->commands));
            
            throw new CommandNotFoundException(
                sprintf('Command "%s" does not exist.', $name),
                $alternatives
            );
        }

        return $this->commands[$name];
    }

    public function findNamespace(string $namespace): string
    {
        $allNamespaces = $this->getNamespaces();
        
        foreach ($allNamespaces as $n) {
            if ($n === $namespace || str_starts_with($namespace, $n . ':')) {
                return $n;
            }
        }

        throw new CommandNotFoundException(
            sprintf('There are no commands defined in the "%s" namespace.', $namespace)
        );
    }

    public function getNamespaces(): array
    {
        $namespaces = [];
        
        foreach ($this->commands as $name => $command) {
            if (str_contains($name, ':')) {
                $namespace = substr($name, 0, strpos($name, ':'));
                $namespaces[$namespace] = true;
            }
        }

        return array_keys($namespaces);
    }

    public function findAlternatives(string $name, array $collection): array
    {
        $alternatives = [];
        $threshold = 1.0;

        foreach ($collection as $item) {
            $distance = levenshtein($name, $item);
            $similarity = 1 - ($distance / max(strlen($name), strlen($item)));

            if ($similarity >= $threshold) {
                $alternatives[] = $item;
            }
        }

        return $alternatives;
    }

    public function setAutoExit(bool $autoExit): self
    {
        $this->autoExit = $autoExit;
        return $this;
    }

    public function getName(): string
    {
        return $this->name;
    }

    public function getVersion(): string
    {
        return $this->version;
    }

    public function getRunningCommand(): ?CommandInterface
    {
        return $this->runningCommand;
    }

    private function showHelp(OutputInterface $output): void
    {
        $output->writeln($this->getHelp());
    }

    private function showVersion(OutputInterface $output): void
    {
        $output->writeln($this->getVersion());
    }

    public function getHelp(): string
    {
        $help = sprintf(
            "%s <info>%s</info> version <comment>%s</comment>\n\n",
            $this->name,
            $this->name,
            $this->version
        );

        $help .= "<info>Usage:</info>\n";
        $help .= "  command [options] [arguments]\n\n";

        $help .= "<info>Options:</info>\n";
        $help .= "  <info>-h, --help</info>            Display this help message\n";
        $help .= "  <info>-v, --version</info>         Display application version\n\n";

        $help .= "<info>Available commands:</info>\n";

        // 按命名空间分组显示命令
        $namespaces = $this->getNamespaces();
        $commands = $this->all();
        
        // 显示无命名空间的命令
        $globalCommands = array_filter($commands, function($name) {
            return !str_contains($name, ':');
        }, ARRAY_FILTER_USE_KEY);

        if (!empty($globalCommands)) {
            foreach ($globalCommands as $name => $command) {
                $help .= sprintf("  <info>%-30s</info> %s\n", $name, $command->getDescription());
            }
            $help .= "\n";
        }

        // 显示命名空间命令
        foreach ($namespaces as $namespace) {
            $help .= sprintf(" <info>%s</info>:\n", $namespace);
            
            $namespaceCommands = array_filter($commands, function($name) use ($namespace) {
                return str_starts_with($name, $namespace . ':');
            }, ARRAY_FILTER_USE_KEY);

            foreach ($namespaceCommands as $name => $command) {
                $shortName = substr($name, strlen($namespace) + 1);
                $help .= sprintf("  <info>%-30s</info> %s\n", $namespace . ':' . $shortName, $command->getDescription());
            }
            $help .= "\n";
        }

        return $help;
    }

    public function renderException(\Exception $exception, OutputInterface $output): void
    {
        $output->writeln('');
        $output->writeln(sprintf('<error>%s</error>', $exception->getMessage()));
        $output->writeln('');

        if ($exception instanceof CommandNotFoundException && !empty($exception->getAlternatives())) {
            $output->writeln('<info>Did you mean one of these?</info>');
            $output->writeln('');
            
            foreach ($exception->getAlternatives() as $alternative) {
                $output->writeln(sprintf('  <info>%s</info>', $alternative));
            }
            $output->writeln('');
        }

        // 显示堆栈跟踪（仅在调试模式下）
        if ($this->isDebug()) {
            $output->writeln('<error>Exception trace:</error>');
            $output->writeln('');
            
            $trace = $exception->getTrace();
            foreach ($trace as $i => $traceItem) {
                $file = $traceItem['file'] ?? 'unknown';
                $line = $traceItem['line'] ?? 'unknown';
                $function = $traceItem['function'] ?? 'unknown';
                $class = $traceItem['class'] ?? '';
                
                $output->writeln(sprintf(
                    ' <info>%d.</info> %s%s%s() at <info>%s:%s</info>',
                    $i + 1,
                    $class ? $class . '::' : '',
                    $function,
                    $file,
                    $line
                ));
            }
        }
    }

    private function isDebug(): bool
    {
        return (bool)($_ENV['DEBUG'] ?? false);
    }

    public function registerDefaultCommands(): self
    {
        // 注册默认命令
        $this->add(new Command\HelpCommand());
        $this->add(new Command\ListCommand());
        $this->add(new Command\VersionCommand());

        return $this;
    }

    public function doRegisterCommand(string $className): self
    {
        if (!class_exists($className)) {
            throw new \InvalidArgumentException(sprintf('Command class "%s" does not exist.', $className));
        }

        $reflection = new \ReflectionClass($className);
        
        if (!$reflection->implementsInterface(CommandInterface::class)) {
            throw new \InvalidArgumentException(sprintf('Command class "%s" must implement CommandInterface.', $className));
        }

        $command = $reflection->newInstance();
        $this->add($command);

        return $this;
    }

    public function loadCommandsFromDirectory(string $directory, string $namespace = ''): self
    {
        if (!is_dir($directory)) {
            return $this;
        }

        $iterator = new \RecursiveIteratorIterator(
            new \RecursiveDirectoryIterator($directory, \RecursiveDirectoryIterator::SKIP_DOTS)
        );

        foreach ($iterator as $file) {
            if ($file->isFile() && $file->getExtension() === 'php') {
                $className = $this->getClassNameFromFile($file->getPathname(), $namespace);
                
                if ($className && class_exists($className)) {
                    try {
                        $this->doRegisterCommand($className);
                    } catch (\InvalidArgumentException $e) {
                        // 忽略无效的命令类
                    }
                }
            }
        }

        return $this;
    }

    private function getClassNameFromFile(string $filePath, string $namespace): ?string
    {
        $content = file_get_contents($filePath);
        
        if (!preg_match('/namespace\s+([^;]+);/', $content, $matches)) {
            return null;
        }

        $fileNamespace = $matches[1];
        $className = basename($filePath, '.php');
        
        return $fileNamespace . '\\' . $className;
    }

    public function setCatchExceptions(bool $catchExceptions): self
    {
        // 这个方法用于向后兼容
        return $this;
    }

    public function renderThrowable(\Throwable $throwable, OutputInterface $output): void
    {
        if ($throwable instanceof \Exception) {
            $this->renderException($throwable, $output);
        } else {
            $output->writeln('');
            $output->writeln(sprintf('<error>%s</error>', $throwable->getMessage()));
            $output->writeln('');
        }
    }
}