//execute move take a possible move to execute,
//keep track of it in the breadcrumbs and update coordination
func executeMove(move string, breadcrumbs *mazelib.Stack, visited map[mazelib.Coordinate]bool, co mazelib.Coordinate) (mazelib.Survey, mazelib.Coordinate, error) {
//add the reverse move to the breadcrumbs stack
breadcrumbs.Push(move)
//perform the move
survey, err := Move(move)
//mark the new room as visited
co = co.TranformByMove(move)
visited[co] = true
return survey, co, err
}
//return a possible move toward not already visited room
func getValidMove(survey mazelib.Survey, visited map[mazelib.Coordinate]bool, co mazelib.Coordinate) (string, error) {
if move := "down"; !survey.Bottom && !visited[co.TranformByMove(move)] {
return move, nil
}
if move := "right"; !survey.Right && !visited[co.TranformByMove(move)] {
return move, nil
}
if move := "up"; !survey.Top && !visited[co.TranformByMove(move)] {
return move, nil
}
if move := "left"; !survey.Left && !visited[co.TranformByMove(move)] {
return move, nil
}
return "", errors.New("No move is allowed")
}
func Iterate(survey mazelib.Survey, breadcrumbs *mazelib.Stack) {
var err error
co := mazelib.Coordinate{0, 0}
//data structure to keep track of already visited rooms
visited := make(map[mazelib.Coordinate]bool)
//start from the cnter (0,0) and set it to visited
visited[co] = true
for true {
//If solution found
if err == mazelib.ErrVictory {
fmt.Printf("Solution with %d steps found\n", breadcrumbs.Len())
return
}
if err != nil {
fmt.Printf("An error happend: |%v|\n", err)
return
}
move, moveErr := getValidMove(survey, visited, co)
//a move forward is possible
if moveErr == nil {
survey, co, err = executeMove(move, breadcrumbs, visited, co)
} else if undoObj, stackErr := breadcrumbs.Pop(); stackErr != mazelib.ErrEmptyStack {
// back up one step and try again
undo := ReverseMove(undoObj.(string))
survey, err = Move(undo)
co = co.TranformByMove(undo)
} else {
fmt.Println("No solution found.")
return
}
}
}
