Powerful Command-Line Applications in Go/

...

/

Displaying Historical Data to the Users

Displaying Historical Data to the Users

Use historical data to display a summary of activities to the users.

We'll cover the following...

Now, let’s update the application interface to display the two new widgets.

Updating the summaryWidgets.go file

Let’s update the file called summaryWidgets.go to define the new widgets. We add the package definition and import list.

We’ll use:

  • The context package to define a cancellation context to close the widgets.
  • The math package to use some mathematical functions.
  • The time package to deal with times and dates.
  • The cell, widgets/barchart, and widgets/linechart packages to create the required widgets.
  • Our pomodoro package to access the repository.
package app
import (
"context"
"math"
"time"
"github.com/mum4k/termdash/cell"
"github.com/mum4k/termdash/widgets/barchart"
"github.com/mum4k/termdash/widgets/linechart"
"pragprog.com/rggo/interactiveTools/pomo/pomodoro"
)
Importing the required list

We create a custom type summary as a collection of summary widgets. We’ll use this type to connect the widgets to the app and update them:

type summary struct {
  bcDay *barchart.BarChart
  lcWeekly *linechart.LineChart
  updateDaily chan bool
  updateWeekly chan bool
}

We define an update() method for the summary type, which will update all summary widgets by sending a value to the update channels. Each widget will have a goroutine waiting for data coming from this channel to update. This is the same approach we used for all the previous widgets:

func (s *summary) update(redrawCh chan<- bool) {
  s.updateDaily <- true
  s.updateWeekly <- true
  redrawCh <- true
}

Defining the newSummary() function

Now we define a newSummary() function that initializes both widgets and returns an instance of summary with them. ...