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

const Step4 = ({
  apiKey,
  s3Link,
  config: generationConfig,
  fileMetadata,
  generatedDataLink,
  setGeneratedDataLink,
  stepNumber,
  stepTitle,
  stepIcon,
  enabled = true,
}) => {
  const [isGenerating, setIsGenerating] = useState(false);
  const [generationStatus, setGenerationStatus] = useState("");
  const [generationProgress, setGenerationProgress] = useState(0);
  const [hasError, setHasError] = useState(false);
  const [errorMessage, setErrorMessage] = useState("");

  const generateSyntheticData = async () => {
    // Prevent action if step is disabled
    if (!enabled) {
      debugLog("Generation attempted but step is disabled");
      return;
    }

    setIsGenerating(true);
    setGenerationStatus("Initializing generation...");
    setGenerationProgress(0);
    setHasError(false);
    setErrorMessage("");

    try {
      debugLog("Starting synthetic data generation", {
        s3Link,
        config: generationConfig,
        fileMetadata,
        apiKeyPrefix: apiKey.substring(0, 8) + "...",
      });

      // Use the ApiService with retry logic
      const result = await ApiService.retryRequest(async () => {
        // Update progress during API call
        setGenerationStatus("Sending request to AI model...");
        setGenerationProgress(10);

        return await ApiService.generateSyntheticData(apiKey, s3Link, {
          ...generationConfig,
          fileSizeBytes: fileMetadata?.fileSizeBytes || 0,
          sourceFileRows: fileMetadata?.sourceFileRows || 0,
        });
      });

      // If the API returns progress updates, handle them
      if (result.jobId) {
        // For now, simulate progress since polling is not implemented
        await simulateProgress();
        // In a real implementation, you would poll for job status here
        setGeneratedDataLink(
          result.data?.fileUrl ||
            result.fileUrl ||
            result.download_link ||
            result.link ||
            result.s3_url
        );
      } else {
        // Simulate progress for immediate results
        await simulateProgress();
        // Handle the specific response format: { "status": "success", "data": { "fileUrl": "..." } }
        const dataLink =
          result.data?.fileUrl ||
          result.fileUrl ||
          result.s3_url ||
          result.download_link ||
          result.link;

        if (!dataLink) {
          throw new Error(
            "No download link received from the API. The generation may have failed on the server side."
          );
        }

        setGeneratedDataLink(dataLink);
      }

      setGenerationStatus("Generation completed successfully!");
      setGenerationProgress(100);

      debugLog("Synthetic data generation completed", {
        downloadLink:
          result.data?.fileUrl ||
          result.fileUrl ||
          result.s3_url ||
          result.download_link ||
          result.link,
        status: result.status,
        message: result.message,
        fullResult: result,
      });
    } catch (error) {
      debugLog("Synthetic data generation failed", error);
      setHasError(true);
      setGenerationProgress(0);

      // Create a user-friendly error message
      let friendlyErrorMessage = "An error occurred during generation.";

      if (error.message.includes("403") || error.message.includes("401")) {
        friendlyErrorMessage =
          "Authentication failed. Please check your API key and try again.";
      } else if (error.message.includes("404")) {
        friendlyErrorMessage =
          "Generation service not found. Please try again later.";
      } else if (error.message.includes("500")) {
        friendlyErrorMessage =
          "Server error occurred. The service may be temporarily unavailable.";
      } else if (
        error.message.includes("timeout") ||
        error.message.includes("TimeoutError")
      ) {
        friendlyErrorMessage =
          "Request timed out. The generation process may take longer than expected. Please try again.";
      } else if (
        error.message.includes("Network") ||
        error.message.includes("fetch")
      ) {
        friendlyErrorMessage =
          "Network error. Please check your internet connection and try again.";
      } else if (error.message.includes("No download link")) {
        friendlyErrorMessage =
          "Generation completed but no download link was provided. Please try generating again.";
      } else if (error.message) {
        friendlyErrorMessage = error.message;
      }

      setErrorMessage(friendlyErrorMessage);
      setGenerationStatus(`❌ Generation failed: ${friendlyErrorMessage}`);
    } finally {
      setIsGenerating(false);
    }
  };

  const simulateProgress = async () => {
    const steps = [
      { progress: 25, message: "Analyzing data structure..." },
      { progress: 50, message: "Training AI model..." },
      { progress: 75, message: "Generating synthetic data..." },
      { progress: 90, message: "Finalizing output..." },
    ];

    for (const step of steps) {
      setGenerationProgress(step.progress);
      setGenerationStatus(step.message);
      await new Promise((resolve) => setTimeout(resolve, 1500));
    }
  };

  const handleDownload = () => {
    if (generatedDataLink) {
      debugLog("Downloading generated data", { link: generatedDataLink });
      // Open in new tab so user can see if download works
      const newWindow = window.open(generatedDataLink, "_blank");

      // If popup blocked, provide fallback
      if (!newWindow) {
        // Fallback: create a temporary download link
        const link = document.createElement("a");
        link.href = generatedDataLink;
        link.download = `synthetic_data_${Date.now()}.csv`;
        document.body.appendChild(link);
        link.click();
        document.body.removeChild(link);
      }
    }
  };

  const handleCopyLink = async () => {
    if (generatedDataLink) {
      try {
        await navigator.clipboard.writeText(generatedDataLink);
        // You could add a toast notification here
        debugLog("Link copied to clipboard");
      } catch (error) {
        debugLog("Failed to copy link:", error);
        // Fallback for older browsers
        const textArea = document.createElement("textarea");
        textArea.value = generatedDataLink;
        document.body.appendChild(textArea);
        textArea.select();
        document.execCommand("copy");
        document.body.removeChild(textArea);
      }
    }
  };

  const isReadyForGeneration =
    apiKey &&
    s3Link &&
    generationConfig.targetColumn &&
    generationConfig.numRows;

  return (
    <div className="step-container fade-in">
      <div className="step-header">
        <h2>
          <span className="step-number">{stepNumber}</span>
          {stepIcon} {stepTitle}
        </h2>
        <p>Generate high-quality synthetic data based on your configuration</p>
      </div>

      <div className="step-body">
        {!generatedDataLink && !isGenerating && !hasError && (
          <div className="generate-section">
            <div
              className={`status-message ${
                isReadyForGeneration ? "info" : "warning"
              }`}
            >
              <div className="status-message-icon">
                {isReadyForGeneration ? "✅" : "⚠️"}
              </div>
              <div className="status-message-content">
                <h4>
                  {isReadyForGeneration
                    ? "Ready for Generation"
                    : "Configuration Required"}
                </h4>
                {!isReadyForGeneration && (
                  <p
                    style={{
                      marginTop: "0.5rem",
                      fontSize: "0.875rem",
                      opacity: 0.9,
                    }}
                  >
                    Please complete all previous steps before generating data.
                  </p>
                )}
                <div className="status-summary">
                  <div className="status-row">
                    <span className="status-label">🔑 API Key:</span>
                    <span
                      className={`status-badge ${
                        apiKey ? "success" : "warning"
                      }`}
                    >
                      {apiKey ? "✓ Valid" : "⚠ Required"}
                    </span>
                  </div>
                  <div className="status-row">
                    <span className="status-label">📊 Data:</span>
                    <span
                      className={`status-badge ${
                        s3Link ? "success" : "warning"
                      }`}
                    >
                      {s3Link ? "✓ Uploaded" : "⚠ Required"}
                    </span>
                  </div>
                  <div className="status-row">
                    <span className="status-label">🎯 Target:</span>
                    <span
                      className={`status-badge ${
                        generationConfig.targetColumn ? "success" : "warning"
                      }`}
                    >
                      {generationConfig.targetColumn
                        ? `✓ ${generationConfig.targetColumn}`
                        : "⚠ Not set"}
                    </span>
                  </div>
                  <div className="status-row">
                    <span className="status-label">📥 Source:</span>
                    <span className="status-badge info">
                      {fileMetadata?.sourceFileRows || 0} rows
                    </span>
                  </div>
                  <div className="status-row">
                    <span className="status-label">📤 Generate:</span>
                    <span className="status-badge info">
                      {generationConfig.numRows} rows
                    </span>
                  </div>
                </div>
              </div>
            </div>

            <button
              className="btn btn-primary generate-btn"
              onClick={generateSyntheticData}
              disabled={!isReadyForGeneration || !enabled}
              style={{ marginTop: "1.5rem" }}
            >
              🎯 Generate Synthetic Data
            </button>
          </div>
        )}

        {isGenerating && (
          <div className="generation-progress">
            <div className="spinner"></div>
            <div className="file-upload-text" style={{ marginTop: "1rem" }}>
              {generationStatus}
            </div>
            <div className="progress-bar">
              <div
                className="progress-fill"
                style={{ width: `${generationProgress}%` }}
              ></div>
            </div>
            <div
              className="file-upload-subtext"
              style={{ marginTop: "0.75rem" }}
            >
              {generationProgress}% Complete • This may take a few minutes
            </div>
          </div>
        )}

        {hasError && !isGenerating && (
          <div className="error-section">
            <div className="status-message error">
              <div className="status-message-icon">❌</div>
              <div className="status-message-content">
                <h4>Generation Failed</h4>
                <p>There was an error generating your synthetic data.</p>
                <div className="error-details">
                  <strong>Error:</strong> {errorMessage}
                </div>
                <div
                  className="error-help"
                  style={{ marginTop: "0.75rem", fontSize: "0.875rem" }}
                >
                  <strong>What you can try:</strong>
                  <ul
                    style={{
                      marginTop: "0.5rem",
                      paddingLeft: "1.5rem",
                      textAlign: "left",
                    }}
                  >
                    <li>Check your internet connection and try again</li>
                    <li>
                      Verify your API key is valid and has sufficient credits
                    </li>
                    <li>Try reducing the number of rows to generate</li>
                    <li>Contact support if the problem persists</li>
                  </ul>
                </div>
              </div>
            </div>

            <div style={{ marginTop: "1.5rem", textAlign: "center" }}>
              <button
                className="btn btn-primary"
                onClick={() => {
                  setHasError(false);
                  setErrorMessage("");
                  setGenerationStatus("");
                  setGenerationProgress(0);
                }}
                style={{ marginRight: "1rem" }}
              >
                🔄 Try Again
              </button>
              <button
                className="btn btn-secondary"
                onClick={() => {
                  // Reset to initial state
                  setHasError(false);
                  setErrorMessage("");
                  setGenerationStatus("");
                  setGenerationProgress(0);
                  setGeneratedDataLink("");
                }}
              >
                🔙 Start Over
              </button>
            </div>
          </div>
        )}

        {generatedDataLink && !isGenerating && (
          <div className="results-section">
            <div
              className="status-message success"
              style={{ marginBottom: "1.5rem" }}
            >
              <div className="status-message-icon">🎉</div>
              <div className="status-message-content">
                <h4>Generation Complete!</h4>
                <p style={{ margin: "0.5rem 0" }}>
                  Successfully generated {generationConfig.numRows} rows of
                  synthetic data targeting the{" "}
                  <strong>{generationConfig.targetColumn}</strong> column.
                </p>
              </div>
            </div>

            <div
              className="data-preview-section"
              style={{ marginTop: "1.5rem" }}
            >
              <div
                className="preview-header"
                style={{
                  display: "flex",
                  justifyContent: "space-between",
                  alignItems: "center",
                  marginBottom: "1rem",
                  flexWrap: "wrap",
                  gap: "1rem",
                }}
              >
                <h4 style={{ margin: 0, color: "var(--text-primary)" }}>
                  📊 Data Preview
                </h4>
                <div
                  className="action-buttons"
                  style={{
                    display: "flex",
                    gap: "0.75rem",
                    flexWrap: "wrap",
                  }}
                >
                  <button
                    className="btn btn-success"
                    onClick={handleDownload}
                    title="Download the generated synthetic data file"
                  >
                    📥 Download
                  </button>
                  <button
                    className="btn btn-outline"
                    onClick={handleCopyLink}
                    title="Copy download link to clipboard"
                  >
                    📋 Copy Link
                  </button>
                  <button
                    className="btn btn-secondary"
                    onClick={() => {
                      setGeneratedDataLink("");
                      setGenerationProgress(0);
                      setGenerationStatus("");
                      setHasError(false);
                      setErrorMessage("");
                    }}
                    title="Generate new synthetic data with different parameters"
                  >
                    🔄 New Generation
                  </button>
                </div>
              </div>

              <DataViewer s3Url={generatedDataLink} showPreviewOnly={true} />

              <div
                className="preview-info"
                style={{
                  marginTop: "1rem",
                  padding: "0.75rem",
                  background: "var(--bg-tertiary)",
                  borderRadius: "8px",
                  fontSize: "0.875rem",
                  color: "var(--text-secondary)",
                  textAlign: "center",
                }}
              >
                💡 Showing preview of first few rows. Download the complete file
                ({generationConfig.numRows} rows) using the button above.
              </div>
            </div>
          </div>
        )}
      </div>
    </div>
  );
};

export default Step4;