Build a weather and saved-location workspace

{
  "schemaVersion": 1,
  "projectId": "f319a0d2-6f8c-4f85-8b89-27e2c2a7f6a1",
  "name": "WeatherDesk",
  "kind": "DesktopApp",
  "ai": {
    "storeChatsInProject": false
  },
  "language": {
    "dialect": "McBasic1",
    "requireExplicit": true,
    "compare": "Binary",
    "defaultArrayBase": 0
  },
  "application": {
    "bundleIdentifier": "com.mcbasic.samples.weatherdesk",
    "version": "0.1.0",
    "buildNumber": "1",
    "startupFormId": "form-main",
    "shutdownMode": "OnStartupFormClosed"
  },
  "forms": [
    {
      "id": "form-main",
      "typeName": "frmWeather",
      "layout": "Forms/frmWeather.form.json",
      "code": "Forms/frmWeather.bas"
    }
  ],
  "modules": [],
  "classes": [],
  "tests": [],
  "references": [],
  "resources": [],
  "targets": [
    "osx-arm64"
  ],
  "capabilities": [],
  "migrations": [
    {
      "id": 1,
      "path": "Database/migrations/0001_initial.sql"
    }
  ]
}

Private Async Sub Form_Shown()
    Dim version As Long

    mBusy = True
    cmdFind.Enabled = False
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    cmdExport.Enabled = False
    lblStatus.Caption = "Opening the local weather database..."

    Try
        Set mDb = Await Sqlite.OpenAsync(AppPaths.DataFile("weatherdesk.db"))
        version = Await mDb.ApplyMigrationsAsync(App.Migrations)
        Await RefreshLocations()
        cmdFind.Enabled = True
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
        cmdExport.Enabled = True
        lblStatus.Caption = CStr(mRows.RowCount) & " saved location(s)."
    Catch failure As McException
        lblStatus.Caption = "Database error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
    End Try
End Sub

Private Async Function RefreshLocations() As Boolean
    Dim command As DbCommand
    Dim rows As Recordset

    Set command = mDb.CreateCommand("SELECT id, label, name, country, latitude, longitude, timezone, tracked, saved_at, updated_at FROM saved_locations ORDER BY label, name, country")
    Set rows = Await command.QueryAsync()
    Set mRows = rows.Bind()
    Set grdLocations.DataSource = mRows
    grdLocations.SelectedIndex = -1
    mSelectedId = 0
    mSelectedRow = -1
    mDeleteArmed = False
    txtLabel.Text = ""
    chkTracked.Checked = True
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    RefreshLocations = True
End Function

Private Async Sub cmdFind_Click()
    Dim query As String
    Dim url As String
    Dim envelopeText As String
    Dim bodyText As String
    Dim envelope As JsonValue
    Dim document As JsonValue
    Dim results As JsonValue
    Dim firstResult As JsonValue
    Dim count As Long

    If mBusy Then Exit Sub
    query = Trim$(txtCity.Text)
    If Len(query) = 0 Then
        lblStatus.Caption = "Enter a city name."
        txtCity.SetFocus
        Exit Sub
    End If

    mBusy = True
    cmdFind.Enabled = False
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    lblStatus.Caption = "Finding the city..."
    Try
        url = "https://geocoding-api.open-meteo.com/v1/search?name="
        url = url & Replace(query, " ", "+") & "&count=5&language=en&format=json"
        envelopeText = Await Http.RequestAsync("GET", url, "{""User-Agent"":""McBasic WeatherDesk""}", "", 10000)
        envelope = Json.Parse(envelopeText)
        If CLng(Json.Value(Json.Get(envelope, "status"))) < 200 Or CLng(Json.Value(Json.Get(envelope, "status"))) >= 300 Then
            Err.Raise 513, "Web request", "The service returned HTTP " & CStr(Json.Value(Json.Get(envelope, "status")))
        End If
        bodyText = CStr(Json.Value(Json.Get(envelope, "body")))
        document = Json.Parse(bodyText)

        If Not Json.Has(document, "results") Then
            lblStatus.Caption = "The location service returned no result list."
            Exit Sub
        End If
        results = Json.Get(document, "results")
        count = Json.Count(results)
        If count = 0 Then
            lblStatus.Caption = "No city matched the search."
            Exit Sub
        End If

        firstResult = Json.At(results, 0)
        mSelectedId = 0
        mSelectedRow = -1
        mDeleteArmed = False
        mSelectedName = CStr(Json.Value(Json.Get(firstResult, "name")))
        mSelectedCountry = CStr(Json.Value(Json.Get(firstResult, "country")))
        mSelectedLatitude = CDbl(Json.Value(Json.Get(firstResult, "latitude")))
        mSelectedLongitude = CDbl(Json.Value(Json.Get(firstResult, "longitude")))
        mSelectedTimezone = ""
        If Json.Has(firstResult, "timezone") Then mSelectedTimezone = CStr(Json.Value(Json.Get(firstResult, "timezone")))
        txtSelected.Text = mSelectedName & ", " & mSelectedCountry
        txtLabel.Text = mSelectedName
        chkTracked.Checked = True

        Await LoadCurrentWeather()
        cmdSave.Enabled = True
        lblStatus.Caption = CStr(count) & " location(s) found. The first result is ready to add."
    Catch failure As McException
        lblStatus.Caption = "API error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdFind.Enabled = True
    End Try
End Sub

Private Async Function LoadCurrentWeather() As Boolean
    Dim url As String
    Dim envelopeText As String
    Dim bodyText As String
    Dim envelope As JsonValue
    Dim document As JsonValue
    Dim current As JsonValue

    url = "https://api.open-meteo.com/v1/forecast?latitude="
    url = url & CStr(mSelectedLatitude) & "&longitude=" & CStr(mSelectedLongitude)
    url = url & "&current=temperature_2m,wind_speed_10m,weather_code"
    url = url & "&timezone=auto"

    envelopeText = Await Http.RequestAsync("GET", url, "{""User-Agent"":""McBasic WeatherDesk""}", "", 10000)
    envelope = Json.Parse(envelopeText)
    If CLng(Json.Value(Json.Get(envelope, "status"))) < 200 Or CLng(Json.Value(Json.Get(envelope, "status"))) >= 300 Then
        Err.Raise 513, "Web request", "The service returned HTTP " & CStr(Json.Value(Json.Get(envelope, "status")))
    End If
    bodyText = CStr(Json.Value(Json.Get(envelope, "body")))
    document = Json.Parse(bodyText)
    If Not Json.Has(document, "current") Then
        lblCurrent.Caption = "The forecast response has no current section."
        LoadCurrentWeather = False
        Exit Function
    End If

    current = Json.Get(document, "current")
    mTemperature = CDbl(Json.Value(Json.Get(current, "temperature_2m")))
    mWindSpeed = CDbl(Json.Value(Json.Get(current, "wind_speed_10m")))
    mWeatherCode = CLng(Json.Value(Json.Get(current, "weather_code")))
    lblCurrent.Caption = "Current: " & CStr(mTemperature) & " °C | Wind: " & CStr(mWindSpeed) & " km/h | Weather code: " & CStr(mWeatherCode)
    LoadCurrentWeather = True
End Function

Private Async Sub cmdSave_Click()
    Dim command As DbCommand
    Dim lookup As DbCommand
    Dim saved As Recordset
    Dim locationId As Long
    Dim tracked As Long

    If mBusy Then Exit Sub
    If Len(Trim$(mSelectedName)) = 0 Then
        lblStatus.Caption = "Find a city before adding it."
        Exit Sub
    End If
    If Len(Trim$(txtLabel.Text)) = 0 Then
        lblStatus.Caption = "Enter a label for the location."
        txtLabel.SetFocus
        Exit Sub
    End If

    tracked = 0
    If chkTracked.Checked Then tracked = 1
    mBusy = True
    cmdSave.Enabled = False
    cmdRefresh.Enabled = False
    Try
        Set command = mDb.CreateCommand("INSERT INTO saved_locations(label, name, country, latitude, longitude, timezone, tracked) VALUES(@label, @name, @country, @latitude, @longitude, @timezone, @tracked)")
        command.AddParameter "@label", Trim$(txtLabel.Text)
        command.AddParameter "@name", mSelectedName
        command.AddParameter "@country", mSelectedCountry
        command.AddParameter "@latitude", mSelectedLatitude
        command.AddParameter "@longitude", mSelectedLongitude
        command.AddParameter "@timezone", mSelectedTimezone
        command.AddParameter "@tracked", tracked
        Await command.ExecuteAsync()

        Set lookup = mDb.CreateCommand("SELECT id FROM saved_locations WHERE name=@name AND country=@country")
        lookup.AddParameter "@name", mSelectedName
        lookup.AddParameter "@country", mSelectedCountry
        Set saved = Await lookup.QueryAsync()
        locationId = CLng(saved.Value(0, "id"))

        Set command = mDb.CreateCommand("INSERT INTO forecast_snapshots(location_id, temperature, wind_speed, weather_code) VALUES(@location_id, @temperature, @wind_speed, @weather_code)")
        command.AddParameter "@location_id", locationId
        command.AddParameter "@temperature", mTemperature
        command.AddParameter "@wind_speed", mWindSpeed
        command.AddParameter "@weather_code", mWeatherCode
        Await command.ExecuteAsync()
        Await RefreshLocations()
        lblStatus.Caption = "Location added and weather snapshot saved in SQLite."
    Catch failure As McException
        lblStatus.Caption = "Add error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
    End Try
End Sub

Private Async Sub cmdUpdate_Click()
    Dim command As DbCommand
    Dim tracked As Long

    If mBusy Then Exit Sub
    If mSelectedId = 0 Then
        lblStatus.Caption = "Select a saved location first."
        Exit Sub
    End If
    If Len(Trim$(txtLabel.Text)) = 0 Then
        lblStatus.Caption = "Enter a label for the location."
        txtLabel.SetFocus
        Exit Sub
    End If

    tracked = 0
    If chkTracked.Checked Then tracked = 1
    mBusy = True
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    Try
        Set command = mDb.CreateCommand("UPDATE saved_locations SET label=@label, tracked=@tracked, updated_at=CURRENT_TIMESTAMP WHERE id=@id")
        command.AddParameter "@label", Trim$(txtLabel.Text)
        command.AddParameter "@tracked", tracked
        command.AddParameter "@id", mSelectedId
        Await command.ExecuteAsync()
        Await RefreshLocations()
        lblStatus.Caption = "Location updated."
    Catch failure As McException
        lblStatus.Caption = "Update error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
    End Try
End Sub

Private Async Sub cmdDelete_Click()
    Dim command As DbCommand

    If mBusy Then Exit Sub
    If mSelectedId = 0 Then
        lblStatus.Caption = "Select a saved location first."
        Exit Sub
    End If
    If Not mDeleteArmed Then
        mDeleteArmed = True
        lblStatus.Caption = "Click Delete again to confirm removal of the selected location."
        Exit Sub
    End If

    mBusy = True
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    Try
        Set command = mDb.CreateCommand("DELETE FROM forecast_snapshots WHERE location_id=@id")
        command.AddParameter "@id", mSelectedId
        Await command.ExecuteAsync()
        Set command = mDb.CreateCommand("DELETE FROM saved_locations WHERE id=@id")
        command.AddParameter "@id", mSelectedId
        Await command.ExecuteAsync()
        Await RefreshLocations()
        lblStatus.Caption = "Location and its weather snapshots deleted."
    Catch failure As McException
        lblStatus.Caption = "Delete error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
    End Try
End Sub

Private Async Sub cmdRefresh_Click()
    If mBusy Then Exit Sub
    mBusy = True
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    Try
        Await RefreshLocations()
        lblStatus.Caption = CStr(mRows.RowCount) & " saved location(s) loaded from SQLite."
    Catch failure As McException
        lblStatus.Caption = "Refresh error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
    End Try
End Sub

Private Async Sub cmdExport_Click()
    Dim command As DbCommand
    Dim rows As Recordset

    If mBusy Then Exit Sub
    mBusy = True
    cmdExport.Enabled = False
    Try
        Set command = mDb.CreateCommand("SELECT label, name, country, latitude, longitude, timezone, tracked, saved_at, updated_at FROM saved_locations ORDER BY label, name, country")
        Set rows = Await command.QueryAsync()
        Await rows.ExportCsvAsync(AppPaths.DataFile("weatherdesk-locations.csv"))
        lblStatus.Caption = CStr(rows.RowCount) & " location(s) exported."
    Catch failure As McException
        lblStatus.Caption = "Export error " & CStr(failure.Number) & ": " & CStr(failure.Message)
    Finally
        mBusy = False
        cmdExport.Enabled = True
    End Try
End Sub

Private Sub grdLocations_SelectionChanged()
    Dim row As Long

    If mRows Is Nothing Then Exit Sub
    row = CInt(grdLocations.SelectedIndex)
    If row < 0 Or row >= mRows.RowCount Then Exit Sub

    mSelectedId = CLng(mRows.Value(row, "id"))
    mSelectedRow = row
    mSelectedName = CStr(mRows.Value(row, "name"))
    mSelectedCountry = CStr(mRows.Value(row, "country"))
    mSelectedLatitude = CDbl(mRows.Value(row, "latitude"))
    mSelectedLongitude = CDbl(mRows.Value(row, "longitude"))
    If IsNull(mRows.Value(row, "timezone")) Then
        mSelectedTimezone = ""
    Else
        mSelectedTimezone = CStr(mRows.Value(row, "timezone"))
    End If
    txtSelected.Text = mSelectedName & ", " & mSelectedCountry
    txtLabel.Text = CStr(mRows.Value(row, "label"))
    chkTracked.Checked = (CInt(mRows.Value(row, "tracked")) <> 0)
    mDeleteArmed = False
    cmdUpdate.Enabled = True
    cmdDelete.Enabled = True
    lblStatus.Caption = "Editing location " & CStr(mSelectedId) & "."
End Sub

Private Sub cmdClear_Click()
    If mBusy Then Exit Sub
    txtCity.Text = ""
    txtSelected.Text = ""
    txtLabel.Text = ""
    chkTracked.Checked = True
    lblCurrent.Caption = "Find a city to load its current weather."
    lblStatus.Caption = "Ready for another search."
    mSelectedId = 0
    mSelectedRow = -1
    mDeleteArmed = False
    mSelectedName = ""
    mSelectedCountry = ""
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    txtCity.SetFocus
End Sub

Private Sub Form_Unload()
    If Not mDb Is Nothing Then
        mDb.Dispose
        Set mDb = Nothing
    End If
End Sub

Option Explicit

Private mDb As Database
Private mRows As BindingSource
Private mBusy As Boolean
Private mSelectedId As Long
Private mSelectedRow As Long
Private mDeleteArmed As Boolean
Private mSelectedName As String
Private mSelectedCountry As String
Private mSelectedLatitude As Double
Private mSelectedLongitude As Double
Private mSelectedTimezone As String
Private mTemperature As Double
Private mWindSpeed As Double
Private mWeatherCode As Long

Private Async Sub Form_Shown()
    Dim version As Long

    mBusy = True
    cmdFind.Enabled = False
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    cmdExport.Enabled = False
    lblStatus.Caption = "Opening the local weather database..."

    Try
        Set mDb = Await Sqlite.OpenAsync(AppPaths.DataFile("weatherdesk.db"))
        version = Await mDb.ApplyMigrationsAsync(App.Migrations)
        Await RefreshLocations()
        cmdFind.Enabled = True
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
        cmdExport.Enabled = True
        lblStatus.Caption = CStr(mRows.RowCount) & " saved location(s)."
    Catch failure As McException
        lblStatus.Caption = "Database error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
    End Try
End Sub

Private Async Function RefreshLocations() As Boolean
    Dim command As DbCommand
    Dim rows As Recordset

    Set command = mDb.CreateCommand("SELECT id, label, name, country, latitude, longitude, timezone, tracked, saved_at, updated_at FROM saved_locations ORDER BY label, name, country")
    Set rows = Await command.QueryAsync()
    Set mRows = rows.Bind()
    Set grdLocations.DataSource = mRows
    grdLocations.SelectedIndex = -1
    mSelectedId = 0
    mSelectedRow = -1
    mDeleteArmed = False
    txtLabel.Text = ""
    chkTracked.Checked = True
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    RefreshLocations = True
End Function

Private Async Sub cmdFind_Click()
    Dim query As String
    Dim url As String
    Dim envelopeText As String
    Dim bodyText As String
    Dim envelope As JsonValue
    Dim document As JsonValue
    Dim results As JsonValue
    Dim firstResult As JsonValue
    Dim count As Long

    If mBusy Then Exit Sub
    query = Trim$(txtCity.Text)
    If Len(query) = 0 Then
        lblStatus.Caption = "Enter a city name."
        txtCity.SetFocus
        Exit Sub
    End If

    mBusy = True
    cmdFind.Enabled = False
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    lblStatus.Caption = "Finding the city..."
    Try
        url = "https://geocoding-api.open-meteo.com/v1/search?name="
        url = url & Replace(query, " ", "+") & "&count=5&language=en&format=json"
        envelopeText = Await Http.RequestAsync("GET", url, "{""User-Agent"":""McBasic WeatherDesk""}", "", 10000)
        envelope = Json.Parse(envelopeText)
        If CLng(Json.Value(Json.Get(envelope, "status"))) < 200 Or CLng(Json.Value(Json.Get(envelope, "status"))) >= 300 Then
            Err.Raise 513, "Web request", "The service returned HTTP " & CStr(Json.Value(Json.Get(envelope, "status")))
        End If
        bodyText = CStr(Json.Value(Json.Get(envelope, "body")))
        document = Json.Parse(bodyText)

        If Not Json.Has(document, "results") Then
            lblStatus.Caption = "The location service returned no result list."
            Exit Sub
        End If
        results = Json.Get(document, "results")
        count = Json.Count(results)
        If count = 0 Then
            lblStatus.Caption = "No city matched the search."
            Exit Sub
        End If

        firstResult = Json.At(results, 0)
        mSelectedId = 0
        mSelectedRow = -1
        mDeleteArmed = False
        mSelectedName = CStr(Json.Value(Json.Get(firstResult, "name")))
        mSelectedCountry = CStr(Json.Value(Json.Get(firstResult, "country")))
        mSelectedLatitude = CDbl(Json.Value(Json.Get(firstResult, "latitude")))
        mSelectedLongitude = CDbl(Json.Value(Json.Get(firstResult, "longitude")))
        mSelectedTimezone = ""
        If Json.Has(firstResult, "timezone") Then mSelectedTimezone = CStr(Json.Value(Json.Get(firstResult, "timezone")))
        txtSelected.Text = mSelectedName & ", " & mSelectedCountry
        txtLabel.Text = mSelectedName
        chkTracked.Checked = True

        Await LoadCurrentWeather()
        cmdSave.Enabled = True
        lblStatus.Caption = CStr(count) & " location(s) found. The first result is ready to add."
    Catch failure As McException
        lblStatus.Caption = "API error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdFind.Enabled = True
    End Try
End Sub

Private Async Function LoadCurrentWeather() As Boolean
    Dim url As String
    Dim envelopeText As String
    Dim bodyText As String
    Dim envelope As JsonValue
    Dim document As JsonValue
    Dim current As JsonValue

    url = "https://api.open-meteo.com/v1/forecast?latitude="
    url = url & CStr(mSelectedLatitude) & "&longitude=" & CStr(mSelectedLongitude)
    url = url & "&current=temperature_2m,wind_speed_10m,weather_code"
    url = url & "&timezone=auto"

    envelopeText = Await Http.RequestAsync("GET", url, "{""User-Agent"":""McBasic WeatherDesk""}", "", 10000)
    envelope = Json.Parse(envelopeText)
    If CLng(Json.Value(Json.Get(envelope, "status"))) < 200 Or CLng(Json.Value(Json.Get(envelope, "status"))) >= 300 Then
        Err.Raise 513, "Web request", "The service returned HTTP " & CStr(Json.Value(Json.Get(envelope, "status")))
    End If
    bodyText = CStr(Json.Value(Json.Get(envelope, "body")))
    document = Json.Parse(bodyText)
    If Not Json.Has(document, "current") Then
        lblCurrent.Caption = "The forecast response has no current section."
        LoadCurrentWeather = False
        Exit Function
    End If

    current = Json.Get(document, "current")
    mTemperature = CDbl(Json.Value(Json.Get(current, "temperature_2m")))
    mWindSpeed = CDbl(Json.Value(Json.Get(current, "wind_speed_10m")))
    mWeatherCode = CLng(Json.Value(Json.Get(current, "weather_code")))
    lblCurrent.Caption = "Current: " & CStr(mTemperature) & " °C | Wind: " & CStr(mWindSpeed) & " km/h | Weather code: " & CStr(mWeatherCode)
    LoadCurrentWeather = True
End Function

Private Async Sub cmdSave_Click()
    Dim command As DbCommand
    Dim lookup As DbCommand
    Dim saved As Recordset
    Dim locationId As Long
    Dim tracked As Long

    If mBusy Then Exit Sub
    If Len(Trim$(mSelectedName)) = 0 Then
        lblStatus.Caption = "Find a city before adding it."
        Exit Sub
    End If
    If Len(Trim$(txtLabel.Text)) = 0 Then
        lblStatus.Caption = "Enter a label for the location."
        txtLabel.SetFocus
        Exit Sub
    End If

    tracked = 0
    If chkTracked.Checked Then tracked = 1
    mBusy = True
    cmdSave.Enabled = False
    cmdRefresh.Enabled = False
    Try
        Set command = mDb.CreateCommand("INSERT INTO saved_locations(label, name, country, latitude, longitude, timezone, tracked) VALUES(@label, @name, @country, @latitude, @longitude, @timezone, @tracked)")
        command.AddParameter "@label", Trim$(txtLabel.Text)
        command.AddParameter "@name", mSelectedName
        command.AddParameter "@country", mSelectedCountry
        command.AddParameter "@latitude", mSelectedLatitude
        command.AddParameter "@longitude", mSelectedLongitude
        command.AddParameter "@timezone", mSelectedTimezone
        command.AddParameter "@tracked", tracked
        Await command.ExecuteAsync()

        Set lookup = mDb.CreateCommand("SELECT id FROM saved_locations WHERE name=@name AND country=@country")
        lookup.AddParameter "@name", mSelectedName
        lookup.AddParameter "@country", mSelectedCountry
        Set saved = Await lookup.QueryAsync()
        locationId = CLng(saved.Value(0, "id"))

        Set command = mDb.CreateCommand("INSERT INTO forecast_snapshots(location_id, temperature, wind_speed, weather_code) VALUES(@location_id, @temperature, @wind_speed, @weather_code)")
        command.AddParameter "@location_id", locationId
        command.AddParameter "@temperature", mTemperature
        command.AddParameter "@wind_speed", mWindSpeed
        command.AddParameter "@weather_code", mWeatherCode
        Await command.ExecuteAsync()
        Await RefreshLocations()
        lblStatus.Caption = "Location added and weather snapshot saved in SQLite."
    Catch failure As McException
        lblStatus.Caption = "Add error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
    End Try
End Sub

Private Async Sub cmdUpdate_Click()
    Dim command As DbCommand
    Dim tracked As Long

    If mBusy Then Exit Sub
    If mSelectedId = 0 Then
        lblStatus.Caption = "Select a saved location first."
        Exit Sub
    End If
    If Len(Trim$(txtLabel.Text)) = 0 Then
        lblStatus.Caption = "Enter a label for the location."
        txtLabel.SetFocus
        Exit Sub
    End If

    tracked = 0
    If chkTracked.Checked Then tracked = 1
    mBusy = True
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    Try
        Set command = mDb.CreateCommand("UPDATE saved_locations SET label=@label, tracked=@tracked, updated_at=CURRENT_TIMESTAMP WHERE id=@id")
        command.AddParameter "@label", Trim$(txtLabel.Text)
        command.AddParameter "@tracked", tracked
        command.AddParameter "@id", mSelectedId
        Await command.ExecuteAsync()
        Await RefreshLocations()
        lblStatus.Caption = "Location updated."
    Catch failure As McException
        lblStatus.Caption = "Update error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
    End Try
End Sub

Private Async Sub cmdDelete_Click()
    Dim command As DbCommand

    If mBusy Then Exit Sub
    If mSelectedId = 0 Then
        lblStatus.Caption = "Select a saved location first."
        Exit Sub
    End If
    If Not mDeleteArmed Then
        mDeleteArmed = True
        lblStatus.Caption = "Click Delete again to confirm removal of the selected location."
        Exit Sub
    End If

    mBusy = True
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    Try
        Set command = mDb.CreateCommand("DELETE FROM forecast_snapshots WHERE location_id=@id")
        command.AddParameter "@id", mSelectedId
        Await command.ExecuteAsync()
        Set command = mDb.CreateCommand("DELETE FROM saved_locations WHERE id=@id")
        command.AddParameter "@id", mSelectedId
        Await command.ExecuteAsync()
        Await RefreshLocations()
        lblStatus.Caption = "Location and its weather snapshots deleted."
    Catch failure As McException
        lblStatus.Caption = "Delete error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
    End Try
End Sub

Private Async Sub cmdRefresh_Click()
    If mBusy Then Exit Sub
    mBusy = True
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    Try
        Await RefreshLocations()
        lblStatus.Caption = CStr(mRows.RowCount) & " saved location(s) loaded from SQLite."
    Catch failure As McException
        lblStatus.Caption = "Refresh error " & CStr(failure.Number) & ": " & failure.Message
    Finally
        mBusy = False
        cmdSave.Enabled = True
        cmdRefresh.Enabled = True
    End Try
End Sub

Private Async Sub cmdExport_Click()
    Dim command As DbCommand
    Dim rows As Recordset

    If mBusy Then Exit Sub
    mBusy = True
    cmdExport.Enabled = False
    Try
        Set command = mDb.CreateCommand("SELECT label, name, country, latitude, longitude, timezone, tracked, saved_at, updated_at FROM saved_locations ORDER BY label, name, country")
        Set rows = Await command.QueryAsync()
        Await rows.ExportCsvAsync(AppPaths.DataFile("weatherdesk-locations.csv"))
        lblStatus.Caption = CStr(rows.RowCount) & " location(s) exported."
    Catch failure As McException
        lblStatus.Caption = "Export error " & CStr(failure.Number) & ": " & CStr(failure.Message)
    Finally
        mBusy = False
        cmdExport.Enabled = True
    End Try
End Sub

Private Sub grdLocations_SelectionChanged()
    Dim row As Long

    If mRows Is Nothing Then Exit Sub
    row = CInt(grdLocations.SelectedIndex)
    If row < 0 Or row >= mRows.RowCount Then Exit Sub

    mSelectedId = CLng(mRows.Value(row, "id"))
    mSelectedRow = row
    mSelectedName = CStr(mRows.Value(row, "name"))
    mSelectedCountry = CStr(mRows.Value(row, "country"))
    mSelectedLatitude = CDbl(mRows.Value(row, "latitude"))
    mSelectedLongitude = CDbl(mRows.Value(row, "longitude"))
    If IsNull(mRows.Value(row, "timezone")) Then
        mSelectedTimezone = ""
    Else
        mSelectedTimezone = CStr(mRows.Value(row, "timezone"))
    End If
    txtSelected.Text = mSelectedName & ", " & mSelectedCountry
    txtLabel.Text = CStr(mRows.Value(row, "label"))
    chkTracked.Checked = (CInt(mRows.Value(row, "tracked")) <> 0)
    mDeleteArmed = False
    cmdUpdate.Enabled = True
    cmdDelete.Enabled = True
    lblStatus.Caption = "Editing location " & CStr(mSelectedId) & "."
End Sub

Private Sub cmdClear_Click()
    If mBusy Then Exit Sub
    txtCity.Text = ""
    txtSelected.Text = ""
    txtLabel.Text = ""
    chkTracked.Checked = True
    lblCurrent.Caption = "Find a city to load its current weather."
    lblStatus.Caption = "Ready for another search."
    mSelectedId = 0
    mSelectedRow = -1
    mDeleteArmed = False
    mSelectedName = ""
    mSelectedCountry = ""
    cmdSave.Enabled = False
    cmdUpdate.Enabled = False
    cmdDelete.Enabled = False
    txtCity.SetFocus
End Sub

Private Sub Form_Unload()
    If Not mDb Is Nothing Then
        mDb.Dispose
        Set mDb = Nothing
    End If
End Sub

CREATE TABLE saved_locations (
    id INTEGER PRIMARY KEY,
    label TEXT NOT NULL,
    name TEXT NOT NULL,
    country TEXT NOT NULL,
    latitude REAL NOT NULL,
    longitude REAL NOT NULL,
    timezone TEXT NULL,
    tracked INTEGER NOT NULL DEFAULT 1,
    saved_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(name, country)
);

CREATE TABLE forecast_snapshots (
    id INTEGER PRIMARY KEY,
    location_id INTEGER NOT NULL,
    fetched_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
    temperature REAL NULL,
    wind_speed REAL NULL,
    weather_code INTEGER NULL
);