gui: Rules tab - the file as text, checked as you type, tested and saved

2 files changed, 418 insertions, 1 deletions

diff --git a/gui/internal/ui/rules.go b/gui/internal/ui/rules.go
new file mode 100644
index 0000000..741f6b1
--- /dev/null
+++ b/gui/internal/ui/rules.go
@@ -0,0 +1,388 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package ui
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"github.com/diamondburned/gotk4/pkg/pango"
+
+	"krino/gui/internal/model"
+	"krino/internal/xdg"
+)
+
+// checkDelay is how long the editor waits after a keystroke before it
+// checks the text (GUI design §5.3).
+const checkDelay = 300
+
+// rulesView is the Rules tab: one directory's file as text, checked as it
+// is typed, with Test on file and Save (GUI design §5.2, §5.3).
+type rulesView struct {
+	w    *Window
+	root *gtk.Box
+
+	dirs   *gtk.DropDown
+	names  []string
+	save   *gtk.Button
+	revert *gtk.Button
+	reload *gtk.Button
+
+	view  *gtk.TextView
+	buf   *gtk.TextBuffer
+	check *gtk.Label
+	diags *gtk.ListBox
+
+	testPath *gtk.Entry
+	testGo   *gtk.Button
+	out      *gtk.TextView
+
+	rules   *model.Rules
+	pending glib.SourceHandle
+	quiet   bool // set while the view is being filled, so no check is armed
+}
+
+func newRulesView(w *Window) *rulesView {
+	r := &rulesView{w: w}
+	r.root = gtk.NewBox(gtk.OrientationVertical, 0)
+
+	r.names = model.RuleFiles(w.engine)
+	names := r.names
+	if len(names) == 0 {
+		names = []string{"none"}
+	}
+	r.dirs = gtk.NewDropDownFromStrings(names)
+	r.save = gtk.NewButtonWithLabel("Save")
+	r.save.AddCSSClass("suggested-action")
+	r.revert = gtk.NewButtonWithLabel("Revert")
+	r.reload = gtk.NewButtonWithLabel("Reload")
+
+	bar := gtk.NewBox(gtk.OrientationHorizontal, 6)
+	bar.SetMarginTop(6)
+	bar.SetMarginStart(6)
+	bar.SetMarginEnd(6)
+	bar.SetMarginBottom(6)
+	bar.Append(gtk.NewLabel("Rules for"))
+	bar.Append(r.dirs)
+	r.check = gtk.NewLabel("")
+	r.check.SetXAlign(0)
+	r.check.SetHExpand(true)
+	r.check.SetEllipsize(pango.EllipsizeEnd)
+	r.check.SetMaxWidthChars(20)
+	bar.Append(r.check)
+	bar.Append(r.reload)
+	bar.Append(r.revert)
+	bar.Append(r.save)
+
+	r.view = gtk.NewTextView()
+	r.view.SetMonospace(true)
+	r.view.SetLeftMargin(8)
+	r.view.SetRightMargin(8)
+	r.view.SetTopMargin(6)
+	r.buf = r.view.Buffer()
+	editScroll := gtk.NewScrolledWindow()
+	editScroll.SetChild(r.view)
+	editScroll.SetVExpand(true)
+	editScroll.SetHExpand(true)
+
+	r.diags = gtk.NewListBox()
+	r.diags.SetSelectionMode(gtk.SelectionSingle)
+	diagScroll := gtk.NewScrolledWindow()
+	diagScroll.SetChild(r.diags)
+	diagScroll.SetSizeRequest(-1, 110)
+
+	left := gtk.NewBox(gtk.OrientationVertical, 0)
+	left.Append(editScroll)
+	left.Append(gtk.NewSeparator(gtk.OrientationHorizontal))
+	left.Append(diagScroll)
+
+	// Test on file: any file under the directory, answered from the text in
+	// the editor rather than from what is saved.
+	r.testPath = gtk.NewEntry()
+	r.testPath.SetPlaceholderText("a file to test, e.g. ~/downloads/a.pdf")
+	r.testPath.SetHExpand(true)
+	r.testGo = gtk.NewButtonWithLabel("Test on file")
+	testBar := gtk.NewBox(gtk.OrientationHorizontal, 6)
+	testBar.SetMarginStart(6)
+	testBar.SetMarginEnd(6)
+	testBar.SetMarginTop(6)
+	testBar.SetMarginBottom(6)
+	testBar.Append(r.testPath)
+	testBar.Append(r.testGo)
+
+	r.out = gtk.NewTextView()
+	r.out.SetEditable(false)
+	r.out.SetMonospace(true)
+	r.out.SetWrapMode(gtk.WrapWordChar)
+	r.out.SetLeftMargin(8)
+	r.out.SetRightMargin(8)
+	r.out.SetTopMargin(6)
+	r.out.Buffer().SetText("Type a file's path and press Test on file to see what these rules would do to it.")
+	outScroll := gtk.NewScrolledWindow()
+	outScroll.SetChild(r.out)
+	outScroll.SetVExpand(true)
+	right := gtk.NewBox(gtk.OrientationVertical, 0)
+	right.Append(testBar)
+	right.Append(gtk.NewSeparator(gtk.OrientationHorizontal))
+	right.Append(outScroll)
+
+	panes := gtk.NewPaned(gtk.OrientationHorizontal)
+	panes.SetStartChild(left)
+	panes.SetEndChild(right)
+	panes.SetResizeStartChild(true)
+	panes.SetResizeEndChild(false)
+	panes.SetShrinkEndChild(false)
+	panes.SetPosition(620)
+	panes.SetVExpand(true)
+
+	r.root.Append(bar)
+	r.root.Append(gtk.NewSeparator(gtk.OrientationHorizontal))
+	r.root.Append(panes)
+
+	r.buf.ConnectChanged(r.onChanged)
+	r.diags.ConnectRowSelected(func(row *gtk.ListBoxRow) {
+		if row != nil {
+			r.goToLine(row.Name())
+		}
+	})
+	r.dirs.Connect("notify::selected", func() { r.open(r.selectedName()) })
+	r.save.ConnectClicked(r.onSave)
+	r.revert.ConnectClicked(func() {
+		if r.rules != nil {
+			r.rules.Revert()
+			r.fill()
+		}
+	})
+	r.reload.ConnectClicked(func() { r.reloadFromDisk() })
+	r.testGo.ConnectClicked(r.onTest)
+	r.testPath.ConnectActivate(r.onTest)
+
+	r.open(r.selectedName())
+	return r
+}
+
+// selectedName is the directory the picker names, "" when none is offered.
+func (r *rulesView) selectedName() string {
+	i := int(r.dirs.Selected())
+	if i < 0 || i >= len(r.names) {
+		return ""
+	}
+	return r.names[i]
+}
+
+// open reads a directory's file into the editor.
+func (r *rulesView) open(name string) {
+	if name == "" {
+		r.check.SetText("no directory has rules of its own yet; add one with: krino new NAME PATH")
+		r.setEditable(false)
+		return
+	}
+	rules, err := model.OpenRules(r.w.engine, name)
+	if err != nil {
+		r.check.SetText(escape(err.Error()))
+		r.setEditable(false)
+		return
+	}
+	r.rules = rules
+	r.setEditable(true)
+	if root := r.w.dirRoot(name); root != "" {
+		r.testPath.SetText(xdg.Abbrev(root) + "/")
+	}
+	r.fill()
+}
+
+// fill puts the model's text in the view and checks it.
+func (r *rulesView) fill() {
+	r.quiet = true
+	r.buf.SetText(r.rules.Text)
+	r.quiet = false
+	r.runCheck()
+}
+
+// setEditable turns the editor on or off as a whole.
+func (r *rulesView) setEditable(on bool) {
+	r.view.SetEditable(on)
+	r.save.SetSensitive(false)
+	r.revert.SetSensitive(on)
+	r.reload.SetSensitive(on)
+	r.testGo.SetSensitive(on)
+}
+
+// onChanged arms the check, one timer at a time: checking on every
+// keystroke would load the whole configuration as the user types.
+func (r *rulesView) onChanged() {
+	if r.quiet || r.rules == nil {
+		return
+	}
+	if r.pending != 0 {
+		glib.SourceRemove(r.pending)
+	}
+	r.pending = glib.TimeoutAdd(checkDelay, func() bool {
+		r.pending = 0
+		r.runCheck()
+		return false
+	})
+}
+
+// text is what the editor holds.
+func (r *rulesView) text() string {
+	start, end := r.buf.Bounds()
+	return r.buf.Text(start, end, true)
+}
+
+// runCheck loads the configuration with the unsaved text and shows what is
+// wrong with it.
+func (r *rulesView) runCheck() {
+	if r.rules == nil {
+		return
+	}
+	r.rules.SetText(r.text())
+	diags := r.rules.Check()
+	clearList(r.diags)
+	switch {
+	case len(diags) == 0:
+		r.check.SetText("check: no errors")
+	case len(diags) == 1:
+		r.check.SetText("check: 1 problem")
+	default:
+		r.check.SetText(fmt.Sprintf("check: %d problems", len(diags)))
+	}
+	for _, d := range diags {
+		where := xdg.Abbrev(d.File)
+		if d.Pos.Line > 0 {
+			where = fmt.Sprintf("%s:%d:%d", where, d.Pos.Line, d.Pos.Col)
+		}
+		line := d.Pos.Line
+		row := gtk.NewListBoxRow()
+		label := gtk.NewLabel(escape(where + ": " + d.Msg))
+		label.SetXAlign(0)
+		label.SetMarginStart(6)
+		label.SetMarginEnd(6)
+		label.SetWrap(true)
+		label.AddCSSClass("error")
+		row.SetChild(label)
+		r.diags.Append(row)
+		if d.File == r.rules.File && line > 0 {
+			row.SetName(fmt.Sprintf("%d", line))
+		}
+	}
+	r.save.SetSensitive(len(diags) == 0 && r.rules.Modified())
+	r.revert.SetSensitive(r.rules.Modified())
+}
+
+// goToLine puts the cursor on the line a diagnostic names, so clicking one
+// shows what it is about. A diagnostic in another file carries no line.
+func (r *rulesView) goToLine(name string) {
+	line, err := strconv.Atoi(name)
+	if err != nil || line <= 0 {
+		return
+	}
+	iter, ok := r.buf.IterAtLine(line - 1)
+	if !ok {
+		return
+	}
+	r.buf.PlaceCursor(iter)
+	r.view.ScrollToIter(iter, 0, true, 0, 0.3)
+	r.view.GrabFocus()
+}
+
+// onSave writes the file, or asks what to do when someone else has.
+func (r *rulesView) onSave() {
+	if r.rules == nil {
+		return
+	}
+	err := r.rules.Save()
+	switch {
+	case err == nil:
+		r.w.setStatus("saved %s; the previous text is beside it as %s.bak",
+			escape(xdg.Abbrev(r.rules.File)), escape(r.rules.Name+".conf"))
+		r.reloadEngine()
+		r.runCheck()
+	case errors.Is(err, model.ErrChangedOnDisk):
+		r.askAboutDiskChange()
+	default:
+		r.w.setStatus("save: %v", err)
+	}
+}
+
+// askAboutDiskChange offers Reload, Overwrite or Cancel when the file has
+// changed since it was opened (GUI design §5.3).
+func (r *rulesView) askAboutDiskChange() {
+	d := gtk.NewMessageDialog(&r.w.win.Window, gtk.DialogModal|gtk.DialogDestroyWithParent,
+		gtk.MessageWarning, gtk.ButtonsNone)
+	d.SetObjectProperty("text", "Something else changed "+escape(xdg.Abbrev(r.rules.File)))
+	d.SetObjectProperty("secondary-text",
+		"Reload takes what is on disk and drops your changes. Overwrite keeps yours and puts the other text in the .bak file.")
+	d.AddButton("Cancel", int(gtk.ResponseCancel))
+	d.AddButton("Reload", int(gtk.ResponseReject))
+	d.AddButton("Overwrite", int(gtk.ResponseAccept))
+	d.ConnectResponse(func(response int) {
+		d.Destroy()
+		switch response {
+		case int(gtk.ResponseReject):
+			r.reloadFromDisk()
+		case int(gtk.ResponseAccept):
+			if err := r.rules.SaveOverwriting(); err != nil {
+				r.w.setStatus("save: %v", err)
+				return
+			}
+			r.w.setStatus("saved over the other change; it is in the .bak file")
+			r.reloadEngine()
+			r.runCheck()
+		}
+	})
+	d.Show()
+}
+
+// reloadFromDisk drops unsaved text and re-reads the file.
+func (r *rulesView) reloadFromDisk() {
+	if r.rules == nil {
+		return
+	}
+	if err := r.rules.Reload(); err != nil {
+		r.w.setStatus("reload: %v", err)
+		return
+	}
+	r.fill()
+}
+
+// reloadEngine makes the saved rules the ones the other tabs use.
+func (r *rulesView) reloadEngine() {
+	if err := r.w.reloadEngine(); err != nil {
+		r.w.setStatus("saved, but the new rules do not load: %v", err)
+	}
+}
+
+// onTest explains one file against the unsaved text, off the main loop:
+// content extraction can take seconds.
+func (r *rulesView) onTest() {
+	if r.rules == nil {
+		return
+	}
+	path := strings.TrimSpace(r.testPath.Text())
+	if path == "" {
+		r.out.Buffer().SetText("Type the path of a file under the directory first.")
+		return
+	}
+	r.rules.SetText(r.text())
+	r.testGo.SetSensitive(false)
+	r.out.Buffer().SetText("testing " + escape(path) + "...")
+	var text string
+	runInBackground(func(ctx context.Context) error {
+		var err error
+		text, err = r.rules.Explain(ctx, path)
+		return err
+	}, func(err error) {
+		r.testGo.SetSensitive(true)
+		if err != nil {
+			r.out.Buffer().SetText(escapeText(err.Error()))
+			return
+		}
+		r.out.Buffer().SetText(escapeText(text))
+	})
+}
diff --git a/gui/internal/ui/window.go b/gui/internal/ui/window.go
index c42a7e8..2453444 100644
--- a/gui/internal/ui/window.go
+++ b/gui/internal/ui/window.go
@@ -27,6 +27,7 @@ type Window struct {
 
 	plan    *planView
 	history *historyView
+	rules   *rulesView
 	status  *gtk.Label
 }
 
@@ -44,7 +45,8 @@ func NewWindow(app *gtk.Application, e *engine.Engine) *Window {
 	notebook.AppendPage(w.plan.root, gtk.NewLabel("Plan"))
 	w.history = newHistoryView(w)
 	notebook.AppendPage(w.history.root, gtk.NewLabel("History & undo"))
-	notebook.AppendPage(placeholder("The rules editor arrives with a later milestone."), gtk.NewLabel("Rules"))
+	w.rules = newRulesView(w)
+	notebook.AppendPage(w.rules.root, gtk.NewLabel("Rules"))
 	// The log is read when the tab is first opened, not at start-up: a
 	// window that only sorts never reads it.
 	loaded := false
@@ -81,6 +83,21 @@ func NewWindow(app *gtk.Application, e *engine.Engine) *Window {
 // Show puts the window on screen.
 func (w *Window) Show() { w.win.Show() }
 
+// reloadEngine re-reads the configuration, after the rules editor saves, so
+// every tab works from the rules the user just wrote. An open plan came
+// from the old ones, so it is closed and its lock released.
+func (w *Window) reloadEngine() error {
+	e, diags := engine.Load(w.engine.MainFile)
+	if len(diags) > 0 {
+		return diags[0]
+	}
+	e.CacheDir = w.engine.CacheDir
+	w.plan.closeTab()
+	w.history.closeTab()
+	w.engine = e
+	return nil
+}
+
 // dirRoot is the path of the configured directory called name, or "" if
 // the configuration no longer has one - a log entry can outlive its
 // directory.
@@ -126,6 +143,18 @@ func escape(s string) string {
 	return b.String()
 }
 
+// escapeText is escape for text shown in a pane rather than on one line:
+// line breaks are the layout, so they are kept, and every other control or
+// bidirectional character is still written as an escape.
+func escapeText(s string) string {
+	var b strings.Builder
+	for _, line := range strings.Split(s, "\n") {
+		b.WriteString(escape(line))
+		b.WriteString("\n")
+	}
+	return strings.TrimSuffix(b.String(), "\n")
+}
+
 // runInBackground runs work off the main loop and hands its result back to
 // the GTK thread with done. GTK may only be touched from the main loop.
 func runInBackground(work func(context.Context) error, done func(error)) context.CancelFunc {