/*
©AngelaMos | 2026
spinner.go

Braille-frame terminal spinner with goroutine lifecycle management

Animates a 10-frame Braille spinner at 80ms intervals using a background
goroutine. Start() and Stop() are safe to call concurrently. The cursor is
hidden during animation and restored on Stop(). Used to indicate scan progress
when verbose mode is off.

Key exports:
  Spinner - spinner with Start() and Stop() methods
  NewSpinner - creates a Spinner with a display message

Connects to:
  cli/scan.go - creates and controls spinners for scan and HIBP check phases
  ui/color.go - uses CyanBold and HiMagenta for frame and message styling
*/

package ui

import (
	"fmt"
	"strings"
	"sync"
	"time"
)

var frames = []string{
	"\u280b", "\u2819", "\u2839", "\u2838",
	"\u283c", "\u2834", "\u2826", "\u2827",
	"\u2807", "\u280f",
}

type Spinner struct {
	msg    string
	done   chan struct{}
	wg     sync.WaitGroup
	mu     sync.Mutex
	active bool
}

func NewSpinner(msg string) *Spinner {
	return &Spinner{msg: msg}
}

func (s *Spinner) Start() {
	s.mu.Lock()
	if s.active {
		s.mu.Unlock()
		return
	}
	s.active = true
	s.done = make(chan struct{})
	s.wg.Add(1)
	s.mu.Unlock()

	go s.run()
}

func (s *Spinner) Stop() {
	s.mu.Lock()
	if !s.active {
		s.mu.Unlock()
		return
	}
	s.active = false
	close(s.done)
	s.mu.Unlock()
	s.wg.Wait()
}

func (s *Spinner) run() {
	defer s.wg.Done()
	defer fmt.Print("\033[?25h")
	fmt.Print("\033[?25l")

	ticker := time.NewTicker(80 * time.Millisecond)
	defer ticker.Stop()

	idx := 0
	for {
		select {
		case <-s.done:
			clearLine()
			fmt.Print("\033[?25h")
			return
		case <-ticker.C:
			frame := frames[idx%len(frames)]
			fmt.Printf(
				"\r  %s %s",
				CyanBold(frame),
				HiMagenta(s.msg),
			)
			idx++
		}
	}
}

func clearLine() {
	fmt.Print("\r" + strings.Repeat(" ", 80) + "\r")
}