feat: Start refactoring code base to be testable

Implement a spreadsheet service abstraction, GAS integration, and Jest testing setup.

src/services/MockSpreadsheetService.ts

@@ -0,0 +1,113 @@
+import { ISpreadsheetService } from "../interfaces/ISpreadsheetService";
+
+export class MockSpreadsheetService implements ISpreadsheetService {
+  // Store data as a map of sheetName -> array of rows (arrays of values)
+  // Row 0 is headers.
+  private sheets: Map<string, any[][]> = new Map();
+
+  constructor(initialData?: { [sheetName: string]: any[][] }) {
+    if (initialData) {
+      for (const [name, rows] of Object.entries(initialData)) {
+        this.sheets.set(name, JSON.parse(JSON.stringify(rows))); // Deep copy
+      }
+    }
+  }
+
+  setSheetData(sheetName: string, data: any[][]) {
+    this.sheets.set(sheetName, data);
+  }
+
+  private getSheet(sheetName: string): any[][] {
+    if (!this.sheets.has(sheetName)) {
+        // Create empty sheet with no headers if accessed but not defined?
+        // Or throw error to mimic GAS?
+        // Let's return empty array or throw.
+        throw new Error(`Sheet '${sheetName}' not found in mock`);
+    }
+    return this.sheets.get(sheetName)!;
+  }
+
+  getHeaders(sheetName: string): string[] {
+    const data = this.getSheet(sheetName);
+    if (data.length === 0) return [];
+    return data[0] as string[];
+  }
+
+  getRowData(sheetName: string, row: number): any[] {
+    const data = this.getSheet(sheetName);
+    // Row is 1-based index
+    if (row > data.length || row < 1) {
+        throw new Error(`Row ${row} out of bounds`);
+    }
+    return data[row - 1]; // Convert to 0-based
+  }
+
+  getRowNumberByColumnValue(sheetName: string, columnName: string, value: any): number | undefined {
+    const data = this.getSheet(sheetName);
+    if (data.length < 2) return undefined; // Only headers or empty
+
+    const headers = data[0];
+    const colIndex = headers.indexOf(columnName);
+    if (colIndex === -1) return undefined;
+
+    for (let i = 1; i < data.length; i++) {
+        if (data[i][colIndex] === value) {
+            return i + 1; // Convert 0-based index to 1-based row number
+        }
+    }
+    return undefined;
+  }
+
+  setCellValueByColumnName(sheetName: string, row: number, columnName: string, value: any): void {
+    const data = this.getSheet(sheetName);
+    const headers = data[0];
+    const colIndex = headers.indexOf(columnName);
+
+    if (colIndex === -1) {
+        throw new Error(`Column '${columnName}' not found`);
+    }
+
+    // Ensure row exists, extend if necessary (basic behavior)
+    while (data.length < row) {
+        data.push(new Array(headers.length).fill(""));
+    }
+
+    data[row - 1][colIndex] = value;
+  }
+
+  getCellValueByColumnName(sheetName: string, row: number, columnName: string): any {
+    const data = this.getSheet(sheetName);
+    const headers = data[0];
+    const colIndex = headers.indexOf(columnName);
+
+    if (colIndex === -1) return null;
+    if (row > data.length) return null;
+
+    return data[row - 1][colIndex];
+  }
+
+  // Helper to store links: key = "sheetName:row:colIndex", value = url
+  private links: Map<string, string> = new Map();
+
+  getCellHyperlink(sheetName: string, row: number, columnName: string): string | null {
+    const data = this.getSheet(sheetName);
+    const colIndex = data[0].indexOf(columnName);
+    if (colIndex === -1) return null;
+
+    const key = `${sheetName}:${row}:${colIndex}`;
+    return this.links.get(key) || null;
+  }
+
+  setCellHyperlink(sheetName: string, row: number, columnName: string, displayText: string, url: string): void {
+     // Set text value
+     this.setCellValueByColumnName(sheetName, row, columnName, displayText);
+
+     // Set link
+     const data = this.getSheet(sheetName);
+     const colIndex = data[0].indexOf(columnName);
+     if (colIndex !== -1) {
+         const key = `${sheetName}:${row}:${colIndex}`;
+         this.links.set(key, url);
+     }
+  }
+}