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

const paths = require('../utils/paths');
const ConfigParser = require('../utils/config-parser');

const router = express.Router();

// Mods listing page
router.get('/', async (req, res) => {
  try {
    paths.ensureDirectories();
    
    let globalMods = [];
    let worlds = [];
    
    // Get global mods
    try {
      const modDirs = await fs.readdir(paths.modsDir);
      
      for (const modDir of modDirs) {
        try {
          const modPath = paths.getModPath(modDir);
          const configPath = paths.getModConfigPath(modDir);
          
          const stats = await fs.stat(modPath);
          if (!stats.isDirectory()) continue;
          
          const config = await ConfigParser.parseModConfig(configPath);
          
          globalMods.push({
            name: modDir,
            title: config.title || modDir,
            description: config.description || '',
            author: config.author || '',
            depends: config.depends || [],
            optional_depends: config.optional_depends || [],
            min_minetest_version: config.min_minetest_version || '',
            max_minetest_version: config.max_minetest_version || '',
            location: 'global',
            path: modPath,
            lastModified: stats.mtime
          });
        } catch (modError) {
          console.error(`Error reading mod ${modDir}:`, modError);
        }
      }
    } catch (dirError) {}
    
    // Get worlds for dropdown
    try {
      const worldDirs = await fs.readdir(paths.worldsDir);
      for (const worldDir of worldDirs) {
        try {
          const worldPath = paths.getWorldPath(worldDir);
          const configPath = paths.getWorldConfigPath(worldDir);
          const stats = await fs.stat(worldPath);
          if (stats.isDirectory()) {
            const config = await ConfigParser.parseWorldConfig(configPath);
            worlds.push({
              name: worldDir,
              displayName: config.server_name || worldDir
            });
          }
        } catch {}
      }
    } catch {}
    
    const selectedWorld = req.query.world;
    let worldMods = [];
    
    if (selectedWorld && paths.isValidWorldName(selectedWorld)) {
      try {
        const worldModsPath = paths.getWorldModsPath(selectedWorld);
        const modDirs = await fs.readdir(worldModsPath);
        
        for (const modDir of modDirs) {
          try {
            const modPath = path.join(worldModsPath, modDir);
            const configPath = path.join(modPath, 'mod.conf');
            
            const stats = await fs.stat(modPath);
            if (!stats.isDirectory()) continue;
            
            const config = await ConfigParser.parseModConfig(configPath);
            
            worldMods.push({
              name: modDir,
              title: config.title || modDir,
              description: config.description || '',
              author: config.author || '',
              depends: config.depends || [],
              optional_depends: config.optional_depends || [],
              location: 'world',
              enabled: true,
              path: modPath,
              lastModified: stats.mtime
            });
          } catch (modError) {
            console.error(`Error reading world mod ${modDir}:`, modError);
          }
        }
      } catch (dirError) {}
    }
    
    res.render('mods/index', {
      title: 'Mod Management',
      globalMods: globalMods,
      worldMods: worldMods,
      worlds: worlds,
      selectedWorld: selectedWorld,
      currentPage: 'mods'
    });
  } catch (error) {
    console.error('Error getting mods:', error);
    res.status(500).render('error', {
      error: 'Failed to load mods',
      message: error.message
    });
  }
});

// Install mod to world
router.post('/install/:worldName/:modName', async (req, res) => {
  try {
    const { worldName, modName } = req.params;
    
    if (!paths.isValidWorldName(worldName) || !paths.isValidModName(modName)) {
      return res.status(400).json({ error: 'Invalid world or mod name' });
    }
    
    const worldPath = paths.getWorldPath(worldName);
    const globalModPath = paths.getModPath(modName);
    const worldModsPath = paths.getWorldModsPath(worldName);
    const targetModPath = path.join(worldModsPath, modName);
    
    try {
      await fs.access(worldPath);
    } catch {
      return res.status(404).json({ error: 'World not found' });
    }
    
    try {
      await fs.access(globalModPath);
    } catch {
      return res.status(404).json({ error: 'Mod not found' });
    }
    
    try {
      await fs.access(targetModPath);
      return res.status(409).json({ error: 'Mod already installed in world' });
    } catch {}
    
    await fs.mkdir(worldModsPath, { recursive: true });
    await fs.cp(globalModPath, targetModPath, { recursive: true });
    
    res.redirect(`/mods?world=${worldName}&installed=${modName}`);
  } catch (error) {
    console.error('Error installing mod to world:', error);
    res.status(500).json({ error: 'Failed to install mod to world' });
  }
});

// Remove mod from world
router.post('/remove/:worldName/:modName', async (req, res) => {
  try {
    const { worldName, modName } = req.params;
    
    if (!paths.isValidWorldName(worldName) || !paths.isValidModName(modName)) {
      return res.status(400).json({ error: 'Invalid world or mod name' });
    }
    
    const worldModsPath = paths.getWorldModsPath(worldName);
    const modPath = path.join(worldModsPath, modName);
    
    try {
      await fs.access(modPath);
    } catch {
      return res.status(404).json({ error: 'Mod not found in world' });
    }
    
    await fs.rm(modPath, { recursive: true, force: true });
    
    res.redirect(`/mods?world=${worldName}&removed=${modName}`);
  } catch (error) {
    console.error('Error removing mod from world:', error);
    res.status(500).json({ error: 'Failed to remove mod from world' });
  }
});

// Delete global mod
router.post('/delete/:modName', async (req, res) => {
  try {
    const { modName } = req.params;
    
    if (!paths.isValidModName(modName)) {
      return res.status(400).json({ error: 'Invalid mod name' });
    }
    
    const modPath = paths.getModPath(modName);
    
    try {
      await fs.access(modPath);
    } catch {
      return res.status(404).json({ error: 'Mod not found' });
    }
    
    await fs.rm(modPath, { recursive: true, force: true });
    
    res.redirect(`/mods?deleted=${modName}`);
  } catch (error) {
    console.error('Error deleting mod:', error);
    res.status(500).json({ error: 'Failed to delete mod' });
  }
});

// Mod details page
router.get('/:modName', async (req, res) => {
  try {
    const { modName } = req.params;
    
    if (!paths.isValidModName(modName)) {
      return res.status(400).render('error', { 
        error: 'Invalid mod name' 
      });
    }
    
    const modPath = paths.getModPath(modName);
    const configPath = paths.getModConfigPath(modName);
    
    try {
      await fs.access(modPath);
    } catch {
      return res.status(404).render('error', { 
        error: 'Mod not found' 
      });
    }
    
    const config = await ConfigParser.parseModConfig(configPath);
    const stats = await fs.stat(modPath);
    
    // Get mod files info
    let fileCount = 0;
    let totalSize = 0;
    
    async function countFiles(dirPath) {
      try {
        const items = await fs.readdir(dirPath);
        for (const item of items) {
          const itemPath = path.join(dirPath, item);
          const itemStats = await fs.stat(itemPath);
          if (itemStats.isDirectory()) {
            await countFiles(itemPath);
          } else {
            fileCount++;
            totalSize += itemStats.size;
          }
        }
      } catch {}
    }
    
    await countFiles(modPath);
    
    // Get worlds where this mod is installed
    const installedWorlds = [];
    try {
      const worldDirs = await fs.readdir(paths.worldsDir);
      for (const worldDir of worldDirs) {
        try {
          const worldModPath = path.join(paths.getWorldModsPath(worldDir), modName);
          await fs.access(worldModPath);
          
          const worldConfigPath = paths.getWorldConfigPath(worldDir);
          const worldConfig = await ConfigParser.parseWorldConfig(worldConfigPath);
          
          installedWorlds.push({
            name: worldDir,
            displayName: worldConfig.server_name || worldDir
          });
        } catch {}
      }
    } catch {}
    
    const modDetails = {
      name: modName,
      title: config.title || modName,
      description: config.description || '',
      author: config.author || '',
      depends: config.depends || [],
      optional_depends: config.optional_depends || [],
      min_minetest_version: config.min_minetest_version || '',
      max_minetest_version: config.max_minetest_version || '',
      location: 'global',
      path: modPath,
      fileCount,
      totalSize,
      created: stats.birthtime,
      lastModified: stats.mtime,
      installedWorlds: installedWorlds,
      config: config
    };
    
    res.render('mods/details', {
      title: `Mod: ${modDetails.title}`,
      mod: modDetails,
      currentPage: 'mods'
    });
  } catch (error) {
    console.error('Error getting mod details:', error);
    res.status(500).render('error', {
      error: 'Failed to load mod details',
      message: error.message
    });
  }
});

module.exports = router;