package main

import (
	"fmt"

	"github.com/beanzilla/gonode"
	"golang.org/x/exp/slices"
)

type TravelPath struct {
	N_Path        *gonode.Node `json:"-"`
	N_Destination *gonode.Node `json:"-"`
	Path          []string     `json:"path"`
	Destination   string       `json:"destination"`
}

func (t *TravelPath) String() string {
	result := ""
	for _, path := range t.Path {
		if result != "" {
			result += " > "
		}
		result += path
	}
	if result != "" {
		result += " >> "
	}
	result += t.Destination
	return result
}

func (t *TravelPath) Parse(n *gonode.Node) error {
	txt := fmt.Sprintf("%v", n.Data())
	switch Key(txt) {
	case "playtime":
		if !n.HasTag("insert", "travel") {
			n.AddTag("insert", "travel")
		}
	case "travel":
		if t.N_Path == nil {
			t.N_Path = n.Parent()
		}
		t.Path = append(t.Path, Value(txt))
		if !n.HasTag("replace", "travel") {
			n.AddTag("replace", "travel")
		}
	case "travel destination":
		t.N_Destination = n
		t.Destination = Value(txt)
	}
	return nil
}

func (t *TravelPath) Update() error {
	if t.N_Path == nil {
		return fmt.Errorf("missing node(s), can't update")
	}
	replaced := false
	// Replace nodes we've seen before (this takes care of if we didn't really change anything)
	// Problems: New items, less items
	for _, path := range t.Path {
		replaced = false
		idx := 0
	FIND_A_NODE:
		for kid := range t.N_Path.Iter() {
			if kid.HasTag("replace", "travel") {
				kid.SetData(fmt.Sprintf("travel %s", Format(path)))
				kid.RmTag("replace", "travel")
				replaced = true
				break FIND_A_NODE
			}
			idx += 1
		}
		if !replaced {
			t.N_Path.NewChildWithData(fmt.Sprintf("travel %s", Format(path)))
		}
	}
	// Cleanup less items (this will remove old/stale stuff)
	idxs := []int{}
	idx := 0
	for idx != -1 {
		idx = t.N_Path.ChildIndexByTag("replace", "travel")
		if !slices.Contains(idxs, idx) {
			idxs = append(idxs, idx)
		} else {
			break
		}
	}
	t.N_Path.RmChild(idxs...)
	// Update the destination
	if t.Destination != "" && t.N_Destination != nil {
		// We have a destination and a node for it
		t.N_Destination.SetData(fmt.Sprintf("%s %s", Format("travel destination"), Format(t.Destination)))
	} else if t.Destination == "" && t.N_Destination != nil {
		// We have no destination but a node
		t.N_Destination.Detach()
		t.N_Destination.Destroy()
	} else if t.Destination != "" && t.N_Destination == nil {
		// We have a destination but no node for it
		t.N_Path.NewChildWithData(fmt.Sprintf("%s %s", Format("travel destination"), Format(t.Destination)))
	}
	return nil
}