Adds GUI with basic histogram

2 files changed, 52 insertions, 0 deletions

diff --git a/gui/src/types/currency/currency.ts b/gui/src/types/currency/currency.ts
new file mode 100644
index 0000000..7c15324
--- /dev/null
+++ b/gui/src/types/currency/currency.ts
@@ -0,0 +1,6 @@
+interface Currency {
+  valueOf(): number;
+  toString(): string;
+}
+
+export default Currency;
diff --git a/gui/src/types/currency/gbp.ts b/gui/src/types/currency/gbp.ts
new file mode 100644
index 0000000..ce24e48
--- /dev/null
+++ b/gui/src/types/currency/gbp.ts
@@ -0,0 +1,46 @@
+import Currency from "./currency";
+
+class Gbp implements Currency {
+  private readonly sign: 1 | -1;
+  private readonly pounds: number;
+  private readonly pence: number;
+
+  constructor(pounds: number, pence: number, sign?: 1 | -1) {
+    sign = sign ?? 1;
+
+    if (Math.round(pounds) !== pounds) {
+      throw new Error(
+        `Cannot construct GBP with non-whole number of pounds: ${pounds}`,
+      );
+    }
+    if (Math.round(pence) !== pence) {
+      throw new Error(
+        `Cannot construct GBP with non-whole number of pence: ${pence}`,
+      );
+    }
+    if (pounds < 0) {
+      throw new Error(
+        `Cannot construct GBP with negative number of pounds: ${pounds}`,
+      );
+    }
+    if (pence < 0) {
+      throw new Error(
+        `Cannot construct GBP with negative number of pounds: ${pounds}`,
+      );
+    }
+
+    this.sign = sign;
+    this.pounds = pounds;
+    this.pence = pence;
+  }
+
+  valueOf(): number {
+    return this.sign * (this.pounds * 100 + this.pence);
+  }
+
+  toString(): string {
+    return `£${this.pounds}·${this.pence < 10 ? `0${this.pence}` : this.pence}`;
+  }
+}
+
+export default Gbp;