import React, { useState, useRef } from "react";
import Papa from "papaparse";
import { ApiService } from "../utils/apiService";
import { config, debugLog } from "../utils/config";

const Step2 = ({
  uploadedFile,
  setUploadedFile,
  s3Link,
  setS3Link,
  fileMetadata,
  setFileMetadata,
  stepNumber,
  stepTitle,
  stepIcon,
  enabled = true,
  // Add API key props for validation
  apiKey,
  isApiKeyValid,
}) => {
  const [outputFormat, setOutputFormat] = useState("tabular");
  const [isUploading, setIsUploading] = useState(false);
  const [csvData, setCsvData] = useState(null);
  const [dragOver, setDragOver] = useState(false);
  const fileInputRef = useRef(null);

  const handleFileUpload = async (file) => {
    // Prevent action if step is disabled
    if (!enabled) {
      debugLog("File upload attempted but step is disabled");
      return;
    }

    if (!file) {
      alert("No file selected");
      return;
    }

    if (!file.name.endsWith(".csv")) {
      alert("Please upload a CSV file. Only CSV files are supported.");
      return;
    }

    // Check file size against configured limit
    const maxSizeBytes = config.maxFileSizeMB * 1024 * 1024;
    if (file.size > maxSizeBytes) {
      alert(
        `File size (${(file.size / 1024 / 1024).toFixed(
          2
        )}MB) exceeds maximum allowed size of ${config.maxFileSizeMB}MB`
      );
      return;
    }

    // Check if file is empty
    if (file.size === 0) {
      alert(
        "The selected file is empty. Please choose a valid CSV file with data."
      );
      return;
    }

    setUploadedFile(file);
    debugLog("File selected for upload", {
      name: file.name,
      size: file.size,
      type: file.type,
    });

    // Initialize file metadata with file size
    setFileMetadata({
      fileSizeBytes: file.size,
      sourceFileRows: 0, // Will be updated after CSV parsing
    });

    // Parse CSV for preview
    Papa.parse(file, {
      complete: (results) => {
        if (results.errors && results.errors.length > 0) {
          debugLog("CSV parsing warnings", results.errors);
        }

        if (!results.data || results.data.length === 0) {
          alert(
            "The CSV file appears to be empty or invalid. Please check your file and try again."
          );
          setUploadedFile(null);
          setFileMetadata({ fileSizeBytes: 0, sourceFileRows: 0 });
          return;
        }

        setCsvData(results.data);

        // Update file metadata with row count
        setFileMetadata({
          fileSizeBytes: file.size,
          sourceFileRows: results.data.length,
        });

        debugLog("CSV parsed for preview", {
          rows: results.data.length,
          columns: results.data[0] ? Object.keys(results.data[0]).length : 0,
        });
      },
      header: true,
      skipEmptyLines: true,
      error: (error) => {
        debugLog("CSV parsing error", error);
        alert("Error parsing CSV file. Please ensure it's a valid CSV format.");
        setUploadedFile(null);
      },
    });

    // Upload to S3 using ApiService
    setIsUploading(true);
    try {
      debugLog("Starting file upload to S3");

      // Use the ApiService with retry logic
      const result = await ApiService.retryRequest(async () => {
        return await ApiService.uploadFileToS3(file);
      });

      // Handle different response structures
      const s3Url =
        result.s3_link || result.link || result.publicUrl || result.url;
      setS3Link(s3Url);
      debugLog("File uploaded successfully", {
        s3Link: s3Url,
        result: result,
      });
    } catch (error) {
      debugLog("File upload failed", error);

      // More specific error messages
      let errorMessage = "Failed to upload file. Please try again.";
      if (error.message.includes("credentials")) {
        errorMessage =
          "AWS credentials are not configured properly. Please check your .env.local file and restart the application.";
      } else if (error.message.includes("bucket")) {
        errorMessage =
          "Storage bucket configuration issue. Please check your S3 bucket name in .env.local file.";
      } else if (error.message.includes("size")) {
        errorMessage = `File size exceeds the maximum limit of ${config.maxFileSizeMB}MB.`;
      } else if (
        error.message.includes("network") ||
        error.message.includes("fetch") ||
        error.message.includes("CORS")
      ) {
        errorMessage =
          "Network/CORS error. This might be due to S3 bucket CORS configuration or network connectivity issues.";
      } else if (error.message.includes("AccessDenied")) {
        errorMessage =
          "Access denied to S3 bucket. Please check your AWS permissions.";
      }

      alert(errorMessage);
      setUploadedFile(null);
      setCsvData(null);
    } finally {
      setIsUploading(false);
    }
  };

  const handleDrop = (e) => {
    // Prevent action if step is disabled
    if (!enabled) return;

    e.preventDefault();
    setDragOver(false);
    const files = e.dataTransfer.files;
    if (files.length > 0) {
      handleFileUpload(files[0]);
    }
  };

  const handleDragOver = (e) => {
    e.preventDefault();
    setDragOver(true);
  };

  const handleDragLeave = (e) => {
    e.preventDefault();
    setDragOver(false);
  };

  const renderDataPreview = () => {
    if (!csvData || csvData.length === 0) return null;

    // Show more rows for better preview (up to 20 rows)
    const previewData = csvData.slice(0, 20);
    const columns = Object.keys(previewData[0]);

    return (
      <div className="data-preview">
        <h4>
          📊 Data Preview ({csvData.length} rows total, showing first{" "}
          {previewData.length})
        </h4>
        <div className="step2-data-table-container">
          <table className="data-table-scrollable">
            <thead>
              <tr>
                {columns.map((col, index) => (
                  <th key={index}>{col}</th>
                ))}
              </tr>
            </thead>
            <tbody>
              {previewData.map((row, index) => (
                <tr key={index}>
                  {columns.map((col, colIndex) => (
                    <td key={colIndex} title={row[col]}>
                      {row[col]}
                    </td>
                  ))}
                </tr>
              ))}
            </tbody>
          </table>
        </div>
        {csvData.length > 20 && (
          <p className="preview-note">
            Showing first 20 rows of {csvData.length} total rows
          </p>
        )}
      </div>
    );
  };

  return (
    <div className="step-container fade-in">
      <div className="step-header">
        <h2>
          <span className="step-number">{stepNumber}</span>
          {stepIcon} {stepTitle}
        </h2>
        <p>
          Choose your output format and upload a CSV file for analysis and
          synthetic data generation.
        </p>
      </div>

      <div className="step-body">
        {!enabled && (
          <div
            className="status-message warning"
            style={{ marginBottom: "1.5rem" }}
          >
            <div className="status-message-icon">⚠️</div>
            <div className="status-message-content">
              <h4>API Key Required</h4>
              <p>
                Please complete Step 1 (API Key Validation) before uploading
                files.
              </p>
            </div>
          </div>
        )}

        <div className="form-group output-format-section">
          <label>Output Format</label>
          <div className="output-options">
            <div
              className={`output-option ${
                outputFormat === "tabular" ? "selected" : ""
              }`}
              onClick={() => setOutputFormat("tabular")}
            >
              <h4>📊 Tabular</h4>
              <p>CSV format with structured rows and columns</p>
            </div>
            <div className="output-option disabled" title="Coming Soon">
              <h4>📄 JSONL (Coming Soon)</h4>
              <p>JSON Lines format for advanced use cases</p>
            </div>
          </div>
        </div>

        <div className="form-group file-upload-section">
          <label>📤 Upload Source File</label>
          {uploadedFile && s3Link ? (
            <div className="file-uploaded">
              <div className="file-info">
                <div className="file-icon">📊</div>
                <div className="file-details">
                  <h4>{uploadedFile.name}</h4>
                  <p>Successfully uploaded and ready for processing</p>
                  <p
                    style={{
                      fontSize: "0.75rem",
                      opacity: 0.8,
                      marginTop: "0.25rem",
                    }}
                  >
                    Size: {(uploadedFile.size / 1024 / 1024).toFixed(2)} MB
                  </p>
                </div>
                <button
                  className="btn btn-secondary"
                  onClick={() => {
                    setUploadedFile(null);
                    setS3Link("");
                    setCsvData(null);
                    setFileMetadata({ fileSizeBytes: 0, sourceFileRows: 0 });
                  }}
                  style={{ marginLeft: "auto" }}
                >
                  🔄 Change File
                </button>
              </div>
            </div>
          ) : (
            <div
              className={`file-upload-area ${dragOver ? "drag-over" : ""}`}
              onDrop={handleDrop}
              onDragOver={handleDragOver}
              onDragLeave={handleDragLeave}
              onClick={() => fileInputRef.current?.click()}
            >
              <input
                ref={fileInputRef}
                type="file"
                accept=".csv"
                onChange={(e) => handleFileUpload(e.target.files[0])}
              />
              {isUploading ? (
                <div>
                  <div className="spinner"></div>
                  <div className="file-upload-text">Uploading your file...</div>
                  <div className="file-upload-subtext">
                    Please wait while we process your data
                  </div>
                </div>
              ) : (
                <div>
                  <div className="file-upload-icon">📊</div>
                  <div className="file-upload-text">
                    Drop your CSV file here
                  </div>
                  <div className="file-upload-subtext">
                    or click to browse • Max {config.maxFileSizeMB}MB • CSV
                    files only
                  </div>
                </div>
              )}
            </div>
          )}
        </div>

        {renderDataPreview()}
      </div>
    </div>
  );
};

export default Step2;