From 71f64dc70eff6ffb92904325b4f963b66fdccd08 Mon Sep 17 00:00:00 2001
From: Lea Laux <lea.laux@st.oth-regensburg.de>
Date: Wed, 23 Dec 2020 15:42:26 +0100
Subject: [PATCH] Start the feature CSV Importer

---
 pygadmin/csv_importer.py | 149 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 149 insertions(+)
 create mode 100644 pygadmin/csv_importer.py

diff --git a/pygadmin/csv_importer.py b/pygadmin/csv_importer.py
new file mode 100644
index 0000000..61a0818
--- /dev/null
+++ b/pygadmin/csv_importer.py
@@ -0,0 +1,149 @@
+import os
+import csv
+
+from pygadmin.database_query_executor import DatabaseQueryExecutor
+
+
+class CSVImporter:
+    def __init__(self, database_connection, csv_file, delimiter=",", null_type="NULL", create_table=True,
+                 table_name=None):
+
+        self.database_connection = database_connection
+        self.csv_file = csv_file
+        self.delimiter = delimiter
+        self.null_type = null_type
+        self.create_table = create_table
+        self.table_name = table_name
+        self.csv_data = []
+        self.data_types = []
+        # TODO: Create functions for connecting the result signal and the error signal
+        self.database_query_executor = DatabaseQueryExecutor()
+
+    def check_existence_csv_file(self):
+        if os.path.exists(self.csv_file):
+            return True
+
+        else:
+            return False
+
+    def parse_csv_file(self):
+        try:
+            with open(self.csv_file) as csv_file:
+                reader = csv.reader(csv_file, delimiter=",")
+
+                for row in reader:
+                    self.csv_data.append(row)
+
+            return True
+
+        except Exception as file_error:
+            return file_error
+
+    def assume_data_types(self):
+        if len(self.csv_data)-2 > 100:
+            check_limit = 100
+
+        else:
+            check_limit = len(self.csv_data) - 2
+
+        self.data_types = [None] * len(self.csv_data[0])
+
+        for check_row in range(1, check_limit):
+            current_row = self.csv_data[check_row]
+
+            for check_column in range(len(current_row)):
+                if self.data_types[check_column] == "TEXT":
+                    break
+
+                value = current_row[check_column]
+                data_type = self.get_data_type(value)
+
+                if data_type != "NULL":
+                    self.data_types[check_column] = data_type
+
+    def get_data_type(self, value):
+        if value == self.null_type:
+            return "NULL"
+
+        try:
+            float(value)
+            return "REAL"
+
+        except ValueError:
+            pass
+
+        try:
+            int(value)
+            return "INT"
+
+        except ValueError:
+            pass
+
+        return "TEXT"
+
+    def create_table_for_csv_data(self):
+        if self.create_table is not True:
+            return
+
+        create_statement = self.get_create_statement()
+
+    def get_create_statement(self):
+        create_table_query = "CREATE TABLE %s ("
+
+        header = self.csv_data[0]
+
+        for column_count in range(len(header)):
+            if column_count != len(header)-1:
+                comma_value = ","
+
+            else:
+                comma_value = ""
+
+            create_column = '"%s" %s{}\n'.format(comma_value)
+            create_table_query = "{}{}".format(create_table_query, create_column)
+
+        create_table_query = "{});".format(create_table_query)
+
+        return create_table_query
+
+    def get_create_parameter(self):
+        parameter_list = []
+
+        if self.table_name is None:
+            slash_split_list = self.csv_file.split("/")
+            self.table_name = slash_split_list[len(slash_split_list) - 1]
+            csv_split_list = self.table_name.split(".csv")
+            self.table_name = csv_split_list[0]
+
+        parameter_list.append(self.table_name)
+
+        header = self.csv_data[0]
+
+        for column_count in range(len(header)):
+            parameter_list.append(header[column_count])
+            parameter_list.append(self.data_types[column_count])
+
+        return parameter_list
+
+    def do_all_the_stuff(self):
+        """
+        Normal persons would call this function "main". This function is only a placeholder to remember me, that I'm
+        going to need a function for doing all the relevant csv stuff, so the user/rest of the program needs only a
+        database connection and a name, function call, boom, everything is working (or not, that's a case for an error).
+        So, strong TODO
+        """
+
+        pass
+
+
+# TODO: Check for file existence, parse file with error handling, assume the data type on a very basic level, check for
+#  create table or insert in existing table, (create table and) insert
+
+if __name__ == "__main__":
+    csv_importer = CSVImporter(None, "/home/lal45210/test.csv")
+    csv_importer.check_existence_csv_file()
+    csv_importer.parse_csv_file()
+    csv_importer.assume_data_types()
+    print(csv_importer.get_create_parameter())
+
+