Major refactor

Refactor the templates to include a header, use csv-metadata-quality
in a subshell instead of trying to import and pass args to it (which
I actually managed to do, but then trying to capture the output was
an issue), and use ansi2html to prepare the CLI output as the HTML.

main.py

@@ -1,5 +1,8 @@
 import os
+import subprocess
+import sys
 
+from ansi2html import Ansi2HTMLConverter
 from csv_metadata_quality.version import VERSION as cli_version
 from flask import Flask, abort, redirect, render_template, request, url_for
 from werkzeug.utils import secure_filename
@@ -32,9 +35,33 @@ def upload_file():
     return "No file selected"
 
 
+# TODO: probably use a base64- and URL-encoded version of the filename here so
+# we can allow results to be saved and shared?
 @app.route("/process/<filename>")
 def process_file(filename):
-    return render_template("process.html", cli_version=cli_version, filename=filename)
+    # do we need to use secure_filename again here?
+    input_file = os.path.join(app.config["UPLOAD_PATH"], filename)
+    # TODO: write an output file based on the input file name
+    output_file = os.path.join(app.config["UPLOAD_PATH"], "test.csv")
+
+    sys.argv = ["", "-i", input_file, "-o", output_file]
+
+    # run subprocess and capture output as UTF-8 so we get a string instead of
+    # bytes for ansi2html
+    results = subprocess.run(
+        ["csv-metadata-quality", "-i", input_file, "-o", output_file],
+        capture_output=True,
+        encoding="UTF-8",
+    )
+    # convert the output to HTML using ansi2html
+    conv = Ansi2HTMLConverter()
+    html = conv.convert(results.stdout)
+    return render_template(
+        "process.html", cli_version=cli_version, filename=filename, stdout=html
+    )
+
+    # I should remember this Flask-specific way to send files to the client
+    # return send_from_directory(app.config["UPLOAD_FOLDER"], filename)
 
 
 if __name__ == "__main__":