v0.15.0 password recovery, phone layout, CLI pager, embed policy fixes

internal/client/display/output.go

@@ -0,0 +1,79 @@
+package display
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"regexp"
+	"strings"
+	"unicode/utf8"
+)
+
+// Out receives everything the client prints. A paged command runs with Out
+// swapped for a buffer, which Page then shows one screen at a time.
+var Out io.Writer = os.Stdout
+
+// Printf, Line and Write are fmt.Printf, fmt.Println and fmt.Print to Out.
+func Printf(format string, args ...any) { fmt.Fprintf(Out, format, args...) }
+func Line(args ...any)                  { fmt.Fprintln(Out, args...) }
+func Write(args ...any)                 { fmt.Fprint(Out, args...) }
+
+var ansiPattern = regexp.MustCompile("\x1b\\[[0-9;?]*[ -/]*[@-~]")
+
+// TermSize returns the terminal's rows and columns, or zeros when the output
+// is not a terminal (then nothing is paged). Platform files set it.
+var TermSize = func() (rows, cols int) { return 0, 0 }
+
+// Page prints text to Out one screen at a time. After each full screen it
+// asks to continue; readLine supplies the answer (an empty line continues,
+// "q" stops). Without a terminal, or when the text fits, it prints at once.
+func Page(text string, readLine func() (string, bool)) {
+	rows, cols := TermSize()
+	lines := strings.Split(strings.TrimRight(text, "\n"), "\n")
+	if rows < 4 || readLine == nil || visualRows(lines, cols) <= rows-1 {
+		if text != "" {
+			fmt.Fprint(Out, strings.TrimRight(text, "\n")+"\n")
+		}
+		return
+	}
+	pageRows := rows - 1 // one line for the prompt
+	used, i := 0, 0
+	for i < len(lines) {
+		need := wrappedRows(lines[i], cols)
+		if used > 0 && used+need > pageRows {
+			remaining := len(lines) - i
+			fmt.Fprintf(Out, "%s-- More (%d lines left; Enter continues, q quits) --%s", Yellow, remaining, Reset)
+			answer, ok := readLine()
+			// Clear the prompt and the echoed answer line.
+			fmt.Fprint(Out, "\r\x1b[2K\x1b[1A\r\x1b[2K")
+			if !ok || strings.HasPrefix(strings.ToLower(strings.TrimSpace(answer)), "q") {
+				return
+			}
+			used = 0
+			continue
+		}
+		fmt.Fprintln(Out, lines[i])
+		used += need
+		i++
+	}
+}
+
+func visualRows(lines []string, cols int) int {
+	total := 0
+	for _, line := range lines {
+		total += wrappedRows(line, cols)
+	}
+	return total
+}
+
+// wrappedRows is how many terminal rows a line takes, ignoring colour codes.
+func wrappedRows(line string, cols int) int {
+	if cols <= 0 {
+		return 1
+	}
+	width := utf8.RuneCountInString(ansiPattern.ReplaceAllString(line, ""))
+	if width == 0 {
+		return 1
+	}
+	return (width + cols - 1) / cols
+}