Create catalog.py

submissions/Muse-Ali/Assignment 3/catalog.py

@@ -0,0 +1,125 @@
+# Author: muse Alinor 
+# A personal movie catalog: add, list, save, and load movies from a file.
+
+from dataclasses import dataclass   # Section 6 – OOP / dataclass
+import sys                          # Section 5 – used for clean exit messaging
+
+
+# ── Section 6: OOP ────────────────────────────────────────────────────────────
+
+@dataclass
+class CatalogItem:
+    """One movie entry with a title, year, and genre."""
+    title: str
+    year: int
+    genre: str
+
+    def __str__(self) -> str:
+        return f"{self.title} ({self.year}) [{self.genre}]"
+
+
+class Catalog:
+    """Holds a collection of CatalogItem objects and exposes add / list_all."""
+
+    def __init__(self) -> None:
+        self.items: list[CatalogItem] = []   # Section 3 – list
+
+    def add_item(self, item: CatalogItem) -> None:
+        self.items.append(item)
+
+    def list_all(self) -> None:
+        if not self.items:
+            print("  (no movies yet)")
+            return
+        for i, item in enumerate(self.items, start=1):   # Section 3 – for loop
+            print(f"  {i}. {item}")                       # Section 6 – __str__
+
+
+# ── Section 4: Functions ──────────────────────────────────────────────────────
+
+DATA_FILE = "catalog.txt"
+
+
+def load_catalog(path: str, catalog: Catalog) -> None:
+    """Read title|year|genre lines into catalog.items."""
+    try:                                                  # Section 5 – try/except
+        with open(path, encoding="utf-8") as fh:         # Section 5 – with open
+            for line in fh:
+                line = line.strip()
+                if not line:
+                    continue
+                parts = line.split("|")
+                if len(parts) != 3:
+                    continue                             # skip malformed lines
+                title, year_str, genre = parts
+                try:
+                    year = int(year_str)
+                except ValueError:
+                    continue                             # skip bad year
+                catalog.add_item(CatalogItem(title=title, year=year, genre=genre))
+    except FileNotFoundError:                            # Section 5 – specific exception
+        pass                                             # first run → start empty
+
+
+def save_catalog(path: str, catalog: Catalog) -> None:
+    """Write catalog.items back to file in title|year|genre format."""
+    with open(path, "w", encoding="utf-8") as fh:       # Section 5 – with open
+        for item in catalog.items:                       # Section 3 – for loop
+            fh.write(f"{item.title}|{item.year}|{item.genre}\n")
+
+
+def main() -> None:
+    """Entry point: build catalog, load data, run menu loop."""
+    # Section 1 – print / intro
+    print("=" * 40)
+    print("   🎬  My Movie Catalog")
+    print("=" * 40)
+
+    catalog = Catalog()                  # Section 6 – instantiate class
+    load_catalog(DATA_FILE, catalog)     # Section 4 – call function
+
+    # Section 3 – while loop;  Section 2 – conditions on menu choice
+    while True:
+        print("\n1) Add  2) List  3) Save  4) Quit")
+        choice = input("Pick: ").strip()   # Section 1 – input
+
+        if choice == "1":                  # Section 2 – if / elif / else
+            title = input("Title: ").strip()
+            if not title:
+                print("  Title cannot be empty.")
+                continue
+
+            year_str = input("Year:  ").strip()
+            try:
+                year = int(year_str)
+            except ValueError:
+                print("  Year must be a whole number.")
+                continue
+
+            genre = input("Genre: ").strip()
+            if not genre:
+                genre = "Unknown"
+
+            catalog.add_item(CatalogItem(title=title, year=year, genre=genre))
+            print(f'  Added "{title}".')
+
+        elif choice == "2":
+            print()
+            catalog.list_all()
+
+        elif choice == "3":
+            save_catalog(DATA_FILE, catalog)   # Section 4 – call function
+            print("  Saved.")
+
+        elif choice == "4":
+            save_catalog(DATA_FILE, catalog)   # save on quit
+            print("Saved. Bye!")
+            break
+
+        else:
+            print("  Please enter 1, 2, 3, or 4.")
+
+
+# ── Section 4: guard ──────────────────────────────────────────────────────────
+if __name__ == "__main__":
+    main()