const fs = require('fs');
const path = require('path');
const express = require('express');

class PluginManager {
  constructor() {
    this.plugins = new Map();
    this.pluginStaticRouters = [];
  }

  loadPlugins(contentDir, app, siteConfig) {
    const pluginsDir = path.join(contentDir, 'plugins');
    this.plugins.clear();

    if (!fs.existsSync(pluginsDir)) {
      return;
    }

    const entries = fs.readdirSync(pluginsDir, { withFileTypes: true });

    for (const entry of entries) {
      if (!entry.isDirectory()) continue;
      const pluginName = entry.name;
      const pluginPath = path.join(pluginsDir, pluginName);
      const manifestPath = path.join(pluginPath, 'plugin.json');
      const entryScriptPath = path.join(pluginPath, 'index.js');

      if (!fs.existsSync(entryScriptPath)) {
        continue;
      }

      try {
        let manifest = { name: pluginName, enabled: true };
        if (fs.existsSync(manifestPath)) {
          manifest = { ...manifest, ...JSON.parse(fs.readFileSync(manifestPath, 'utf8')) };
        }

        // Check if enabled in site config (default true if not explicitly false)
        const configEntry = siteConfig.plugins && siteConfig.plugins[pluginName];
        if (configEntry === false || (configEntry && configEntry.enabled === false)) {
          console.log(`[PluginManager] Plugin ${pluginName} is disabled in config`);
          continue;
        }

        // Clear module cache for hot reload
        delete require.cache[require.resolve(entryScriptPath)];
        const pluginModule = require(entryScriptPath);

        const pluginInstance = {
          name: pluginName,
          manifest,
          module: pluginModule,
          config: (configEntry && typeof configEntry === 'object') ? configEntry : {}
        };

        // Mount public assets if directory exists
        const publicDir = path.join(pluginPath, 'public');
        if (fs.existsSync(publicDir) && app) {
          app.use(`/plugins/${pluginName}`, express.static(publicDir));
        }

        // Run onInit hook
        if (typeof pluginModule.onInit === 'function' && app) {
          try {
            pluginModule.onInit({
              app,
              config: siteConfig,
              pluginConfig: pluginInstance.config
            });
          } catch (initErr) {
            console.error(`[PluginManager] Error in onInit for plugin ${pluginName}:`, initErr);
          }
        }

        this.plugins.set(pluginName, pluginInstance);
        console.log(`[PluginManager] Loaded plugin: ${pluginName}`);
      } catch (err) {
        console.error(`[PluginManager] Failed to load plugin ${pluginName}:`, err);
      }
    }
  }

  applyMarkdownHooks(markdownIt) {
    for (const [name, plugin] of this.plugins) {
      if (typeof plugin.module.onMarkdownInit === 'function') {
        try {
          plugin.module.onMarkdownInit({ markdownIt, pluginConfig: plugin.config });
        } catch (err) {
          console.error(`[PluginManager] Error in onMarkdownInit for ${name}:`, err);
        }
      }
    }
  }

  applyPostHooks(post) {
    for (const [name, plugin] of this.plugins) {
      if (typeof plugin.module.onPostLoad === 'function') {
        try {
          plugin.module.onPostLoad({ post, pluginConfig: plugin.config });
        } catch (err) {
          console.error(`[PluginManager] Error in onPostLoad for ${name}:`, err);
        }
      }
    }
  }

  async triggerCommentCreated(comment, post) {
    for (const [name, plugin] of this.plugins) {
      if (typeof plugin.module.onCommentCreated === 'function') {
        try {
          await plugin.module.onCommentCreated({ comment, post, pluginConfig: plugin.config });
        } catch (err) {
          console.error(`[PluginManager] Error in onCommentCreated for ${name}:`, err);
        }
      }
    }
  }

  renderHook(hookName, context) {
    let output = '';
    for (const [name, plugin] of this.plugins) {
      if (typeof plugin.module[hookName] === 'function') {
        try {
          const res = plugin.module[hookName]({ ...context, pluginConfig: plugin.config });
          if (res && typeof res === 'string') {
            output += '\n' + res;
          }
        } catch (err) {
          console.error(`[PluginManager] Error in ${hookName} for ${name}:`, err);
        }
      }
    }
    return output;
  }
}

module.exports = new PluginManager();