<?php
namespace Game\System;

use Game\Event\Event;
use Game\Event\EventListenerInterface;
use Game\Event\EventDispatcher;
use Game\Model\Item;
use Game\Model\Player;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Helper\QuestionHelper;
use Symfony\Component\Console\Question\Question;

/**
 * ShopService: 负责处理商店的购买和出售交易。
 */
class ShopService implements EventListenerInterface {

    private EventDispatcher $dispatcher;
    private StateManager $stateManager;
    private InputInterface $input;
    private OutputInterface $output;
    private QuestionHelper $helper;

    // 商店的固定库存（通常从配置加载）
    private array $shopInventory;

    public function __construct(EventDispatcher $dispatcher, StateManager $stateManager, InputInterface $input, OutputInterface $output, QuestionHelper $helper) {
        $this->dispatcher = $dispatcher;
        $this->stateManager = $stateManager;
        $this->input = $input;
        $this->output = $output;
        $this->helper = $helper;
        $this->loadShopInventory();
    }

    private function loadShopInventory(): void {
        // 模拟商店出售的物品配置 (ID 对应 LootService::loadItemData)
        $this->shopInventory = [
            // 商店物品 ID => 价格倍数（如果价格不是 Item::value）
            1 => ['stock' => 10, 'price' => 10], // 小药水
            3 => ['stock' => 5, 'price' => 100], // 新物品：高级药水
        ];
    }

    public function handleEvent(Event $event): void {
        switch ($event->getType()) {
            case 'OpenShopEvent': // 响应 InteractionSystem 的请求
                $this->startShopping();
                break;
        }
    }

    /**
     * 启动商店界面和循环
     */
    private function startShopping(): void {
        $this->dispatcher->dispatch(new Event('SystemMessage', ['message' => "\n欢迎光临！看看我有什么好东西。"]));
        $running = true;

        while ($running) {
            $player = $this->stateManager->getPlayer();
            $this->displayShopMenu($player);

            $question = new Question("> 请选择操作 (B:购买 | S:出售 | X:退出)：");
            $choice = strtoupper($this->helper->ask($this->input, $this->output, $question) ?? '');

            switch ($choice) {
                case 'B':
                    $this->handlePurchase();
                    break;
                case 'S':
                    $this->handleSelling();
                    break;
                case 'X':
                    $running = false;
                    $this->dispatcher->dispatch(new Event('SystemMessage', ['message' => '下次再来！']));
                    break;
                default:
                    $this->dispatcher->dispatch(new Event('SystemMessage', ['message' => '无效的指令。']));
            }
        }
    }

    // --- 购买逻辑 ---

    private function handlePurchase(): void {
        $this->displaySaleItems();
        $player = $this->stateManager->getPlayer();

        $question = new Question("> 输入要购买的物品编号 (或 X 退出)：");
        $choice = strtoupper($this->helper->ask($this->input, $this->output, $question) ?? '');

        if ($choice === 'X') return;

        if (is_numeric($choice)) {
            $itemId = (int)$choice;
            if (isset($this->shopInventory[$itemId])) {
                $price = $this->shopInventory[$itemId]['price'];

                if ($player->spendGold($price)) {
                    // ⭐ 触发事件请求 LootService 给予物品（重用 LootService 的逻辑）
                    $this->dispatcher->dispatch(new Event('ShopPurchaseEvent', ['itemId' => $itemId]));

                    $this->dispatcher->dispatch(new Event('SystemMessage', [
                        'message' => "交易成功！花费 {$price} 💰，剩余 {$player->getGold()} 💰。"
                    ]));
                } else {
                    $this->dispatcher->dispatch(new Event('SystemMessage', ['message' => "金币不足！你需要 {$price} 💰。"]));
                }
            } else {
                $this->dispatcher->dispatch(new Event('SystemMessage', ['message' => '商店没有这个编号的物品。']));
            }
        }
    }

    // --- 出售逻辑 ---

    private function handleSelling(): void {
        $player = $this->stateManager->getPlayer();
        if (empty($player->getInventory())) {
            $this->dispatcher->dispatch(new Event('SystemMessage', ['message' => '你的背包是空的，没有什么可卖的。']));
            return;
        }

        $this->displaySellableItems($player);

        $question = new Question("> 输入要出售的物品编号 (背包索引 | 或 X 退出)：");
        $choice = strtoupper($this->helper->ask($this->input, $this->output, $question) ?? '');

        if ($choice === 'X') return;

        if (is_numeric($choice)) {
            $index = (int)$choice;
            $inventory = $player->getInventory();

            if (isset($inventory[$index])) {
                $item = $inventory[$index];
                // 简化：出售价格为 Item::value 的一半
                $sellPrice = floor($item->value / 2);

                // 移除物品并获得金币
                $player->removeItemByIndex($index);
                $player->gainGold($sellPrice);

                $this->dispatcher->dispatch(new Event('SystemMessage', [
                    'message' => "💰 出售了 <fg=white>{$item->name}</>，获得 {$sellPrice} 💰。剩余 {$player->getGold()} 💰。"
                ]));

                // 触发 UI 更新
                $this->dispatcher->dispatch(new Event('InventoryUpdateEvent'));

            } else {
                $this->dispatcher->dispatch(new Event('SystemMessage', ['message' => '无效的背包编号。']));
            }
        }
    }

    // --- UI 辅助方法 ---

    private function displayShopMenu(Player $player): void {
        $this->output->writeln("\n--- 商店主页 ---");
        $this->output->writeln("你的金币: <fg=yellow>{$player->getGold()}</> 💰");
        $this->output->writeln("--------------------------");
    }

    private function displaySaleItems(): void {
        $this->output->writeln("\n--- 🛒 商店出售 ---");
        // 模拟获取 Item 数据的服务（实际应通过 ItemService/DB）
        $itemsData = [
            1 => ['name' => '小型治疗药水', 'value' => 10, 'type' => 'potion'],
            3 => ['name' => '高级治疗药水', 'value' => 200, 'type' => 'potion'], // 假设 ID 3
        ];

        foreach ($this->shopInventory as $itemId => $data) {
            $name = $itemsData[$itemId]['name'] ?? "未知物品";
            $price = $data['price'];
            $this->output->writeln("[<fg=green>{$itemId}</>] {$name} | 价格: <fg=yellow>{$price}</> 💰");
        }
        $this->output->writeln("--------------------------");
    }

    private function displaySellableItems(Player $player): void {
        $this->output->writeln("\n--- 📦 出售你的物品 ---");
        $inventory = $player->getInventory();

        if (empty($inventory)) return;

        foreach ($inventory as $index => $item) {
            $sellPrice = floor($item->value / 2);
            $this->output->writeln("[<fg=green>{$index}</>] <fg=white>{$item->name}</> | 售价: <fg=yellow>{$sellPrice}</> 💰");
        }
        $this->output->writeln("--------------------------");
    }
}