package model

// MaxHistory tracks max command history
const MaxHistory = 20

// History represents a command history.
type History struct {
	commands []string
	limit    int
}

// NewHistory returns a new instance.
func NewHistory(limit int) *History {
	return &History{limit: limit}
}

func (h *History) List() []string {
	return h.commands
}

// Push adds a new item.
func (h *History) Push(c string) {
	if i := h.indexOf(c); i != -1 {
		h.commands = append(h.commands[:i], h.commands[i+1:]...)
	}
	if len(h.commands) < h.limit {
		h.commands = append(h.commands, c)
		return
	}
	h.commands = append(h.commands[1:], c)
}

// Clear clear out the stack using pops.
func (h *History) Clear() {
	h.commands = nil
}

// Empty returns true if no history.
func (h *History) Empty() bool {
	return len(h.commands) == 0
}

func (h *History) indexOf(s string) int {
	for i, c := range h.commands {
		if c == s {
			return i
		}
	}
	return -1
}