diff --git a/nginxfmt.py b/nginxfmt.py
index b592824..71721f7 100755
--- a/nginxfmt.py
+++ b/nginxfmt.py
@@ -1,11 +1,97 @@
 #!/usr/bin/env python3
 
+"""add module description
+"""
+
 import argparse
 
-argparser = argparse.ArgumentParser()
+import re
+
+__author__ = "Michał Słomkowski"
+__license__ = "Apache 2.0"
+
+INDENTATION = ' ' * 4
+
+
+def strip_line(single_line):
+    within_quotes = False
+    parts = []
+    for part in re.split('"', single_line.strip()):
+        if within_quotes:
+            parts.append(part)
+        else:
+            parts.append(re.sub(r'[\s]+', ' ', part))
+        within_quotes = not within_quotes
+    return '"'.join(parts)
+
+
+def clean_lines(orig_lines):
+    cleaned_lines = []
+    for line in orig_lines:
+        line = strip_line(line)
+        if line == "":
+            cleaned_lines.append("")
+            continue
+        else:
+            cleaned_lines.extend([l.strip() for l in re.split("([\\{\\}])", line) if l != ""])
+
+    return cleaned_lines
+
+
+def join_opening_parenthesis(lines):
+    modified_lines = []
+    for i in range(len(lines)):
+        if i > 0 and lines[i] == "{":
+            modified_lines[-1] += " {"
+        else:
+            modified_lines.append(lines[i])
+    return modified_lines
+
+
+def perform_indentation(lines):
+    indented_lines = []
+    current_indent = 0
+    for line in lines:
+        if line.endswith('}') and current_indent > 0:
+            current_indent -= 1
+
+        indented_lines.append(current_indent * INDENTATION + line)
+
+        if line.endswith('{'):
+            current_indent += 1
+
+    return indented_lines
+
+
+def format_config_file(contents):
+    lines = clean_lines(contents.splitlines())
+    lines = join_opening_parenthesis(lines)
+    lines = perform_indentation(lines)
+
+    return '\n'.join(lines) + '\n'
+
+
+if __name__ == "__main__":
+    argparser = argparse.ArgumentParser(description=__doc__)
+
+    argparser.add_argument("-v", "--verbose", action="store_true", help="show formatted file names")
+    argparser.add_argument("-b", "--backup-original", action="store_true", help="backup original config file")
+    argparser.add_argument("config_file", type=argparse.FileType('r'), nargs='+')
+
+    args = argparser.parse_args()
+
+    for config_file in args.config_file:
+        original_file_content = config_file.read()
+        config_file.close()
 
-argparser.add_argument("-v", "--verbose", action="store_true", help="show formatted file names")
-argparser.add_argument("-b", "--backup-original", action="store_true", help="backup original config file")
-argparser.add_argument("config_file", type=argparse.FileType('r'), nargs='+')
+        with open(config_file.name, 'w') as fp:
+            fp.write(format_config_file(original_file_content))
+        if args.verbose:
+            print("Formatted file %s" % config_file.name)
 
-args = argparser.parse_args()
+        if args.backup_original:
+            backup_file_path = config_file.name + '~'
+            with open(backup_file_path, 'w') as fp:
+                fp.write(original_file_content)
+            if args.verbose:
+                print("Original saved to %s" % backup_file_path)
diff --git a/test_nginxfmt.py b/test_nginxfmt.py
new file mode 100644
index 0000000..8e5771c
--- /dev/null
+++ b/test_nginxfmt.py
@@ -0,0 +1,79 @@
+import unittest
+
+from nginxfmt import *
+
+
+class TestFormatter(unittest.TestCase):
+    def _check_formatting(self, original_text, formatted_text):
+        self.assertEqual(formatted_text, format_config_file(original_text))
+
+    def test_join_opening_parenthesis(self):
+        self.assertEqual(["foo", "bar {", "johan {", "tee", "ka", "}"],
+                         join_opening_parenthesis(("foo", "bar {", "johan", "{", "tee", "ka", "}")))
+
+    def test_clear_lines(self):
+        self.assertEqual(["ala", "ma", "{", "kota", "}", "to;", "", "ook"],
+                         clean_lines(("ala", "ma  {", "kota", "}", "to;", "", "ook")))
+
+        self.assertEqual(["ala", "ma", "{", "{", "kota", "}", "to", "}", "ook"],
+                         clean_lines(("ala", "ma  {{", "kota", "}", "to}", "ook")))
+
+        self.assertEqual(["{", "ala", "ma", "{", "{", "kota", "}", "to", "}"],
+                         clean_lines(("{", "ala  ", "ma  {{", "  kota ", "}", " to} ")))
+
+    def test_perform_indentation(self):
+        self.assertEqual([
+            "foo bar {",
+            "    fizz bazz;",
+            "}"], perform_indentation(("foo bar {", "fizz bazz;", "}")))
+
+        self.assertEqual([
+            "foo bar {",
+            "    fizz bazz {",
+            "        lorem ipsum;",
+            "        asdf asdf;",
+            "    }",
+            "}"], perform_indentation(("foo bar {", "fizz bazz {", "lorem ipsum;", "asdf asdf;", "}", "}")))
+
+        self.assertEqual([
+            "foo bar {",
+            "    fizz bazz {",
+            "        lorem ipsum;",
+            "    }",
+            "}",
+            "}",
+            "foo {"], perform_indentation(("foo bar {", "fizz bazz {", "lorem ipsum;", "}", "}", "}", "foo {")))
+
+    def test_strip_line(self):
+        self.assertEqual("foo", strip_line("  foo  "))
+        self.assertEqual("bar foo", strip_line("   bar   foo  "))
+        self.assertEqual("bar foo", strip_line("   bar \t  foo  "))
+        self.assertEqual('lorem ipsum " foo  bar zip "', strip_line('  lorem   ipsum   " foo  bar zip " '))
+        self.assertEqual('lorem ipsum " foo  bar zip " or "  dd aa  " mi',
+                         strip_line('  lorem   ipsum   " foo  bar zip "  or \t "  dd aa  "  mi'))
+
+    def test_indentation(self):
+        self._check_formatting(
+            "  foo bar {\n" +
+            "       lorem ipsum;\n" +
+            "}",
+            "foo bar {\n" +
+            "    lorem ipsum;\n" +
+            "}\n")
+
+        self._check_formatting(
+            "  foo bar {\n" +
+            "       lorem ipsum;\n" +
+            " kee {\n" +
+            "caak;  \n" +
+            "}}",
+            "foo bar {\n" +
+            "    lorem ipsum;\n" +
+            "    kee {\n" +
+            "        caak;\n" +
+            "    }\n" +
+            "}\n")
+
+
+if __name__ == '__main__':
+    unittest.main()