// Package banner renders the operator-facing blocks that carry a
// plaintext credential.
//
// A generated password printed as one more structured log line is lost:
// a boot writes roughly 45 fx PROVIDE/RUN/HOOK lines around it, and
// under `docker run -d` it is one line in a log subject to rotation. A
// credential that is shown exactly once has to be findable by eye when
// an operator scrolls back, so it is written as a ruled block rather
// than as a log record.
//
// It is deliberately not a log line: it goes straight to the writer the
// caller names — standard output for both the first-boot account and
// the `resetpw` subcommand — so it is neither levelled, filtered, nor
// rendered as JSON by whichever handler internal/logger installed.
package banner

import (
	"fmt"
	"io"
	"strings"
)

// ruleWidth is the length of the horizontal rules, chosen to fit an
// 80-column terminal without wrapping.
const ruleWidth = 72

// Credentials writes a ruled block naming an account and its plaintext
// password. headline says which event produced it, and note says what
// the operator must do about it; both are written verbatim, so a
// multi-line note must already be wrapped.
func Credentials(
	w io.Writer,
	headline, username, password, note string,
) error {
	rule := strings.Repeat("=", ruleWidth)

	_, err := fmt.Fprintf(
		w,
		"\n%s\n%s\n\n    username: %s\n    password: %s\n\n%s\n%s\n\n",
		rule, headline, username, password, note, rule,
	)
	if err != nil {
		return fmt.Errorf("writing credentials banner: %w", err)
	}

	return nil
}