From 2673c92b4e6ac530ef2c6eca901bb7611ea7360d Mon Sep 17 00:00:00 2001
From: Akumatic <akumatic@outlook.com>
Date: Thu, 4 May 2023 10:41:12 +0200
Subject: [PATCH] Add functionality to generate an overview of the db

---
 convert.py            |  19 ++++---
 convert/statistics.py | 112 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+), 6 deletions(-)
 create mode 100644 convert/statistics.py

diff --git a/convert.py b/convert.py
index fec51cd..d687338 100644
--- a/convert.py
+++ b/convert.py
@@ -3,15 +3,16 @@
 
 import logging
 import argparse
+from convert.statistics import Statistics
 from convert.utf8mb4converter import UTF8MB4Converter
 
 def main (
         args: argparse.Namespace
     ) -> None:
     """ 
-    Main program sequence. Establishes a connection to the database, converts
-    the default charset and collation of the database itself, all tables and 
-    all text fields to UTF8MB4 if its not in UTF8MB4 yet.
+    Main program sequence. Establishes a connection to the database and either creates statistics 
+    or converts the database itself, all tables and all text fields to utf8mb4 if they don't already
+    have this character set.
 
     Params:
     - args (argparse.Namespace)
@@ -25,9 +26,14 @@ def main (
         port = args.port,
         db = args.database
     )
-    db.convert_charset_db()
-    db.convert_charset_all_tables()
-    db.convert_charset_all_columns_all_tables()
+
+    if args.statistics:
+        stats = Statistics(db)
+        logging.getLogger("Main").info(f"Database statistics:\n{stats}")
+    else:
+        db.convert_charset_db()
+        db.convert_charset_all_tables()
+        db.convert_charset_all_columns_all_tables()
 
 def parse_args (
     ) -> argparse.Namespace:
@@ -43,6 +49,7 @@ def parse_args (
     args_req: argparse._ArgumentGroup = argparser.add_argument_group("Required Arguments")
 
     args_opt.add_argument("-v", "--verbose", action="store_true")
+    args_opt.add_argument("-s", "--statistics", action="store_true")
 
     args_req.add_argument("-H", "--host", required=True)
     args_req.add_argument("-P", "--port", required=True, type=int)
diff --git a/convert/statistics.py b/convert/statistics.py
new file mode 100644
index 0000000..2db98fc
--- /dev/null
+++ b/convert/statistics.py
@@ -0,0 +1,112 @@
+# SPDX-License-Identifier: MIT
+# Copyright (c) 2023 Akumatic
+
+from json import dumps
+from collections import defaultdict
+from .utf8mb4converter import UTF8MB4Converter, DEFAULT_CHARSET
+
+class Statistics:
+    """
+    Class for creating statistics that give an overview of the character set status of the database
+
+    Attributes:
+    - dbcon (UTF8MB4Converter)
+        - The converter object storing the database information and connection 
+    - data (dict)
+        - A dictionary holding the generated data: Number of tables & columns and character set overview
+    """
+
+    def __init__ (
+            self,
+            dbcon: UTF8MB4Converter
+        ) -> None:
+        """
+        Constructor of Statistics object. Generates statistics at creation.
+
+        Parameters:
+        - dbcon (UTF8MB4Converter)
+            - The converter object storing the database information and connection 
+        """
+
+        self.dbcon = dbcon
+        self.data: dict = None
+        self.update_stats()
+    
+    def __str__ (
+            self
+        ) -> str:
+        """
+        String representation method. Prints the data stored if the object is passed to print() or str()
+
+        Returns:
+        - A string representation of the data stored in the object by calling get_data_formatted_str
+        """
+
+        return self.get_data_formatted_str()
+    
+    def get_data_formatted_str (
+            self,
+            indent: int = 4
+        ) -> str:
+        """
+        Formats the stored data for better readability.
+
+        Parameters:
+        - indent (int)
+            - number of spaces for indentation
+            - default value: 4
+
+        Returns:
+        - String representation of the data stored in the object
+        """
+
+        return dumps(self.data, indent=indent)
+    
+    def update_stats ( 
+            self
+        ) -> None:
+        """
+        Fetches data from the database and stores it in the object.
+        """
+
+        tables = self.dbcon.get_tables()
+
+        # store dict with count of tables and columns
+        count_tab = len(tables)
+        count_col = 0
+
+        # store dict with count of different charsets of tables and columns
+        charset_tab = defaultdict(int)
+        charset_col = defaultdict(int)
+
+        # fill prepared dicts with data
+        for table in tables:
+            charset = self.dbcon.get_charset_table(table)["charset"]
+            charset_tab[charset] += 1
+
+            columns = self.dbcon.get_columns_of_table(table)
+            count_col += len(columns)
+            for column in columns:
+                charset_col[column["charset"]] += 1
+        
+        # store generated data into the object itself
+        self.data = {
+            "count": {
+                "tables": count_tab,
+                "columns": count_col
+            },
+            "charset": {
+                "tables": charset_tab,
+                "columns": charset_col
+            },
+            "converted": {
+                "tables": {
+                    "converted": charset_tab[DEFAULT_CHARSET],
+                    "missing": count_tab - charset_tab[DEFAULT_CHARSET]
+                },
+                "columns": {
+                    "converted": charset_col[DEFAULT_CHARSET],
+                    "missing": count_col - charset_col[DEFAULT_CHARSET] - charset_col[None]
+                }
+            }
+        }
\ No newline at end of file