/**
 * Form utilities for handling form submissions with progress tracking
 */

class FormHandler {
  constructor(formId, options = {}) {
    this.form = document.getElementById(formId);
    this.options = {
      progressModalId: "progressModal",
      progressBarId: "progressBar",
      progressStatusId: "progressStatus",
      statusCheckInterval: 1000,
      onSuccess: null,
      onError: null,
      onProgress: null,
      ...options,
    };

    this.progressModal = null;
    this.progressBar = null;
    this.progressStatus = null;
    this.submitButton = null;

    this.initElements();
    this.initEventListeners();
  }

  /**
   * Initialize DOM elements
   */
  initElements() {
    if (this.options.progressModalId) {
      const modalElement = document.getElementById(
        this.options.progressModalId
      );
      if (modalElement && typeof bootstrap !== "undefined") {
        this.progressModal = new bootstrap.Modal(modalElement);
      }
    }

    this.progressBar = document.getElementById(this.options.progressBarId);
    this.progressStatus = document.getElementById(
      this.options.progressStatusId
    );
    this.submitButton = this.form?.querySelector('button[type="submit"]');
  }

  /**
   * Initialize event listeners
   */
  initEventListeners() {
    if (this.form) {
      this.form.addEventListener("submit", (e) => this.handleSubmit(e));
    }
  }

  /**
   * Handle form submission
   * @param {Event} e - Form submit event
   */
  async handleSubmit(e) {
    e.preventDefault();

    // Show progress modal
    this.showProgress();
    this.updateProgress(5, "Starting...");

    // Disable submit button
    if (this.submitButton) {
      this.submitButton.disabled = true;
    }

    const formData = new FormData(this.form);

    try {
      const response = await fetch(this.form.action, {
        method: "POST",
        body: formData,
      });

      const data = await response.json();

      if (data.error) {
        this.handleError(data.error);
        return;
      }

      // Start polling for task status if task_id is provided
      if (data.task_id) {
        this.pollTaskStatus(data.task_id);
      } else {
        // Handle immediate response
        this.handleSuccess(data);
      }
    } catch (error) {
      console.error("Form submission failed:", error);
      this.handleError("Form submission failed. Please try again.");
    }
  }

  /**
   * Poll task status for long-running operations
   * @param {string} taskId - Task ID to poll
   */
  async pollTaskStatus(taskId) {
    const checkStatus = async () => {
      try {
        // Construct status URL - this should be customizable
        const statusUrl = this.options.statusUrlTemplate
          ? this.options.statusUrlTemplate.replace("{taskId}", taskId)
          : `/upload/task_status/${taskId}`;

        const response = await fetch(statusUrl);
        const status = await response.json();

        console.log("Task status:", status);

        if (status.state === "SUCCESS") {
          this.updateProgress(100, "Completed!");
          setTimeout(() => {
            this.hideProgress();
            this.handleSuccess(status.result);
          }, 1000);
        } else if (status.state === "FAILURE") {
          this.updateProgress(100, "Failed!", true);
          setTimeout(() => {
            this.hideProgress();
            this.handleError(status.error || "Unknown error occurred");
          }, 1000);
        } else {
          // Update progress
          const progress = status.progress || 0;
          this.updateProgress(progress, `Processing... (${status.state})`);

          // Continue polling
          setTimeout(checkStatus, this.options.statusCheckInterval);
        }
      } catch (error) {
        console.error("Failed to check task status:", error);
        // Continue polling on error
        setTimeout(checkStatus, this.options.statusCheckInterval);
      }
    };

    checkStatus();
  }

  /**
   * Show progress modal
   */
  showProgress() {
    if (this.progressModal) {
      this.progressModal.show();
    }
  }

  /**
   * Hide progress modal
   */
  hideProgress() {
    if (this.progressModal) {
      this.progressModal.hide();
    }
  }

  /**
   * Update progress display
   * @param {number} percentage - Progress percentage (0-100)
   * @param {string} message - Status message
   * @param {boolean} isError - Whether this is an error state
   */
  updateProgress(percentage, message, isError = false) {
    if (this.progressBar) {
      this.progressBar.style.width = `${percentage}%`;
      this.progressBar.textContent = `${percentage}%`;

      if (isError) {
        this.progressBar.classList.add("bg-danger");
      }
    }

    if (this.progressStatus) {
      this.progressStatus.textContent = message;
    }

    // Call custom progress callback
    if (this.options.onProgress) {
      this.options.onProgress(percentage, message, isError);
    }
  }

  /**
   * Handle successful form submission
   * @param {object} result - Success result data
   */
  handleSuccess(result) {
    // Re-enable submit button
    if (this.submitButton) {
      this.submitButton.disabled = false;
    }

    // Call custom success callback
    if (this.options.onSuccess) {
      this.options.onSuccess(result);
    } else {
      // Default success handling
      showFlashMessage("Operation completed successfully!", "success");
    }
  }

  /**
   * Handle form submission error
   * @param {string} error - Error message
   */
  handleError(error) {
    this.hideProgress();

    // Re-enable submit button
    if (this.submitButton) {
      this.submitButton.disabled = false;
    }

    // Call custom error callback
    if (this.options.onError) {
      this.options.onError(error);
    } else {
      // Default error handling
      showFlashMessage(`Error: ${error}`, "error");
    }
  }
}