Exercise 1

ex1/app.go

@@ -0,0 +1,90 @@
+package main
+
+import (
+	"context"
+
+	"git.cems.dev/cdricms/bdooc/proto"
+	"github.com/wailsapp/wails/v2/pkg/runtime"
+)
+
+// App struct
+type App struct {
+	ctx       context.Context
+	employees *proto.EmployeeList // Caching purposes
+}
+
+// NewApp creates a new App application struct
+func NewApp() *App {
+	return &App{}
+}
+
+// startup is called when the app starts. The context is saved
+// so we can call the runtime methods
+func (a *App) startup(ctx context.Context) {
+	a.ctx = ctx
+}
+
+func (a *App) GetEmployees(path string, limit, page uint, column, query *string) ([]*proto.Employee, error) {
+	if a.employees == nil {
+		e, err := proto.LoadFromFile(path)
+		if err != nil {
+			return nil, err
+		}
+		a.employees = e
+	}
+
+	if column != nil && query != nil {
+		e, err := a.employees.QueryEmployeesByColumn(proto.EmployeeField(proto.SnakeCaseToPascalCase(*column)), *query)
+		if err != nil {
+			return nil, err
+		}
+		if uint(len(e)) < page*limit+limit {
+			return e[page*limit:], nil
+		}
+		return e[page*limit : page*limit+limit], nil
+	}
+
+	if uint(len(a.employees.Employees)) < page*limit+limit {
+		return a.employees.Employees[page*limit:], nil
+	}
+	return a.employees.Employees[page*limit : page*limit+limit], nil
+}
+
+func (a *App) GetProtoPath() string {
+	return a.OpenPath([]runtime.FileFilter{{
+		DisplayName: "Proto binary file",
+		Pattern:     "*.bin",
+	}})
+}
+
+func (a *App) OpenPath(filters []runtime.FileFilter) string {
+	path, err := runtime.OpenFileDialog(a.ctx, runtime.OpenDialogOptions{
+		Filters: filters,
+	})
+
+	if err != nil {
+		panic(err)
+	}
+
+	return path
+}
+
+type FunctionAgg string
+
+const (
+	AVG = FunctionAgg("AVG")
+	SUM = FunctionAgg("SUM")
+)
+
+func (a *App) AggregateByColumn(groupBy proto.EmployeeField, on proto.EmployeeField, function FunctionAgg) map[string]float64 {
+	return proto.AggregateByColumn(a.employees, proto.EmployeeField(proto.SnakeCaseToPascalCase(string(groupBy))), func(ep proto.EmployeePList) float64 {
+		switch function {
+		case AVG:
+			return proto.Average(ep, proto.EmployeeField(proto.SnakeCaseToPascalCase(string(on))))
+		case SUM:
+			return proto.Sum(ep, proto.EmployeeField(proto.SnakeCaseToPascalCase(string(on))))
+		}
+
+		return 0.0
+	})
+}