import { NextRequest, NextResponse } from 'next/server';
import { whoAmI, createRepo, uploadFiles, datasetInfo } from '@huggingface/hub';
import { readdir, stat, readFile } from 'fs/promises';
import path from 'path';

export async function POST(request: NextRequest) {
  try {
    const body = await request.json();
    const { action, token, namespace, datasetName, datasetPath, datasetId, artifacts, manifest } = body;

    if (!token) {
      return NextResponse.json({ error: 'HF token is required' }, { status: 400 });
    }

    switch (action) {
      case 'whoami':
        try {
          const user = await whoAmI({ accessToken: token });
          return NextResponse.json({ user });
        } catch (error) {
          return NextResponse.json({ error: 'Invalid token or network error' }, { status: 401 });
        }

      case 'createDataset':
        try {
          if (!namespace || !datasetName) {
            return NextResponse.json({ error: 'Namespace and dataset name required' }, { status: 400 });
          }

          const repoId = `datasets/${namespace}/${datasetName}`;
          
          // Create repository
          await createRepo({
            repo: repoId,
            accessToken: token,
            private: false,
          });

          return NextResponse.json({ success: true, repoId });
        } catch (error: any) {
          if (error.message?.includes('already exists')) {
            return NextResponse.json({ success: true, repoId: `${namespace}/${datasetName}`, exists: true });
          }
          return NextResponse.json({ error: error.message || 'Failed to create dataset' }, { status: 500 });
        }

      case 'uploadDataset':
        try {
          if (!namespace || !datasetName) {
            return NextResponse.json({ error: 'Missing required parameters' }, { status: 400 });
          }

          const repoId = `datasets/${namespace}/${datasetName}`;
          const structuredArtifacts = Array.isArray(artifacts) ? artifacts : [];
          const hasStructuredArtifacts = structuredArtifacts.length > 0;

          if (!hasStructuredArtifacts && !datasetPath) {
            return NextResponse.json({ error: 'Dataset path could not be resolved' }, { status: 400 });
          }

          const filesToUpload: { path: string; content: any }[] = [];
          const uploadedPaths = new Set<string>();

          const normalizeRepoPath = (value: string) => value.replace(/\\/g, '/').replace(/^\/+/, '');

          const addUploadContent = (repoFilePath: string, content: Blob) => {
            const normalizedRepoPath = normalizeRepoPath(repoFilePath);
            if (!normalizedRepoPath || uploadedPaths.has(normalizedRepoPath)) {
              return;
            }
            uploadedPaths.add(normalizedRepoPath);
            filesToUpload.push({ path: normalizedRepoPath, content });
          };

          const addUploadFile = async (absolutePath: string, repoFilePath: string) => {
            const buffer = await readFile(absolutePath);
            const blob = new Blob([buffer]);
            addUploadContent(repoFilePath, blob);
          };

          const walkDirectory = async (basePath: string, repoPrefix: string) => {
            const entries = await readdir(basePath, { withFileTypes: true });
            for (const entry of entries) {
              const entryPath = path.join(basePath, entry.name);
              if (entry.isDirectory()) {
                const nextPrefix = repoPrefix ? `${repoPrefix}/${entry.name}` : entry.name;
                await walkDirectory(entryPath, nextPrefix);
              } else if (entry.isFile()) {
                const repoFilePath = repoPrefix ? `${repoPrefix}/${entry.name}` : entry.name;
                await addUploadFile(entryPath, repoFilePath);
              }
            }
          };

          const processArtifact = async (localPath: string, repoPath: string) => {
            const resolvedPath = path.resolve(localPath);
            let stats;
            try {
              stats = await stat(resolvedPath);
            } catch {
              throw new Error(`Dataset path does not exist: ${localPath}`);
            }

            const normalizedRepoPrefix = repoPath ? normalizeRepoPath(repoPath) : '';

            if (stats.isDirectory()) {
              await walkDirectory(resolvedPath, normalizedRepoPrefix);
            } else if (stats.isFile()) {
              let destination = normalizedRepoPrefix;
              if (!destination || destination.endsWith('/')) {
                destination = `${destination}${path.basename(resolvedPath)}`;
              } else if (!path.posix.extname(destination)) {
                destination = `${destination}/${path.basename(resolvedPath)}`;
              }
              await addUploadFile(resolvedPath, destination);
            } else {
              throw new Error(`Unsupported artifact type for path: ${localPath}`);
            }
          };

          if (hasStructuredArtifacts) {
            for (const artifact of structuredArtifacts) {
              if (!artifact?.localPath || !artifact?.repoPath) {
                continue;
              }
              await processArtifact(artifact.localPath, artifact.repoPath);
            }
          } else {
            const resolvedDatasetPath = path.resolve(datasetPath);
            let datasetStats;
            try {
              datasetStats = await stat(resolvedDatasetPath);
            } catch {
              return NextResponse.json({ error: 'Dataset path does not exist' }, { status: 400 });
            }

            if (!datasetStats.isDirectory()) {
              return NextResponse.json({ error: 'Dataset path must be a directory' }, { status: 400 });
            }

            await walkDirectory(resolvedDatasetPath, '');
          }

          if (manifest) {
            const manifestBlob = new Blob([
              JSON.stringify(manifest, null, 2)
            ], { type: 'application/json' });
            addUploadContent('manifest.json', manifestBlob);
          }

          if (filesToUpload.length === 0) {
            return NextResponse.json({ error: 'No files found to upload for dataset' }, { status: 400 });
          }

          await uploadFiles({
            repo: repoId,
            accessToken: token,
            files: filesToUpload,
          });

          return NextResponse.json({ success: true, repoId });
        } catch (error: any) {
          console.error('Upload error:', error);
          return NextResponse.json({ error: error.message || 'Failed to upload dataset' }, { status: 500 });
        }

      case 'listFiles':
        try {
          if (!datasetPath) {
            return NextResponse.json({ error: 'Dataset path required' }, { status: 400 });
          }

          const files = await readdir(datasetPath, { withFileTypes: true });
          const imageExtensions = ['.jpg', '.jpeg', '.png', '.webp', '.bmp'];
          
          const imageFiles = files
            .filter(file => file.isFile())
            .filter(file => imageExtensions.some(ext => file.name.toLowerCase().endsWith(ext)))
            .map(file => ({
              name: file.name,
              path: path.join(datasetPath, file.name),
            }));

          const captionFiles = files
            .filter(file => file.isFile())
            .filter(file => file.name.endsWith('.txt'))
            .map(file => ({
              name: file.name,
              path: path.join(datasetPath, file.name),
            }));

          return NextResponse.json({ 
            images: imageFiles, 
            captions: captionFiles,
            total: imageFiles.length 
          });
        } catch (error: any) {
          return NextResponse.json({ error: error.message || 'Failed to list files' }, { status: 500 });
        }

      case 'validateDataset':
        try {
          if (!datasetId) {
            return NextResponse.json({ error: 'Dataset ID required' }, { status: 400 });
          }

          // Try to get dataset info to validate it exists and is accessible
          const dataset = await datasetInfo({
            name: datasetId,
            accessToken: token,
          });

          return NextResponse.json({ 
            exists: true, 
            dataset: {
              id: dataset.id,
              author: dataset.author,
              downloads: dataset.downloads,
              likes: dataset.likes,
              private: dataset.private,
            }
          });
        } catch (error: any) {
          if (error.message?.includes('404') || error.message?.includes('not found')) {
            return NextResponse.json({ exists: false }, { status: 200 });
          }
          if (error.message?.includes('401') || error.message?.includes('403')) {
            return NextResponse.json({ error: 'Dataset not accessible with current token' }, { status: 403 });
          }
          return NextResponse.json({ error: error.message || 'Failed to validate dataset' }, { status: 500 });
        }

      default:
        return NextResponse.json({ error: 'Invalid action' }, { status: 400 });
    }
  } catch (error: any) {
    console.error('HF Hub API error:', error);
    return NextResponse.json({ error: error.message || 'Internal server error' }, { status: 500 });
  }
}