package histlist

import "log"

// Histlist is a deduplicated list of cmdLines
type Histlist struct {
	// list of commands lines (deduplicated)
	List []string
	// lookup: cmdLine -> last index
	LastIndex map[string]int
}

// New Histlist
func New() Histlist {
	return Histlist{LastIndex: make(map[string]int)}
}

// Copy Histlist
func Copy(hl Histlist) Histlist {
	newHl := New()
	// copy list
	newHl.List = make([]string, len(hl.List))
	copy(newHl.List, hl.List)
	// copy map
	for k, v := range hl.LastIndex {
		newHl.LastIndex[k] = v
	}
	return newHl
}

// AddCmdLine to the histlist
func (h *Histlist) AddCmdLine(cmdLine string) {
	lenBefore := len(h.List)
	// lookup
	idx, found := h.LastIndex[cmdLine]
	if found {
		// remove duplicate
		if cmdLine != h.List[idx] {
			log.Println("histlist ERROR: Adding cmdLine:", cmdLine, " != LastIndex[cmdLine]:", h.List[idx])
		}
		h.List = append(h.List[:idx], h.List[idx+1:]...)
		// idx++
		for idx < len(h.List) {
			cmdLn := h.List[idx]
			h.LastIndex[cmdLn]--
			if idx != h.LastIndex[cmdLn] {
				log.Println("histlist ERROR: Shifting LastIndex idx:", idx, " != LastIndex[cmdLn]:", h.LastIndex[cmdLn])
			}
			idx++
		}
	}
	// update last index
	h.LastIndex[cmdLine] = len(h.List)
	// append new cmdline
	h.List = append(h.List, cmdLine)
	log.Println("histlist: Added cmdLine:", cmdLine, "; history length:", lenBefore, "->", len(h.List))
}

// AddHistlist contents of another histlist to this histlist
func (h *Histlist) AddHistlist(h2 Histlist) {
	for _, cmdLine := range h2.List {
		h.AddCmdLine(cmdLine)
	}
}