Add history

state/history.go

@@ -0,0 +1,136 @@
+package state
+
+import "strconv"
+
+// History returns the gameplay history for replays
+func (s *State) History() string {
+	return s.history
+}
+
+func UnmarshalAll(history string) *State {
+	s := Unmarshal(history)
+	for {
+		if !s.Step() {
+			break
+		}
+	}
+	return s
+}
+
+func Unmarshal(history string) *State {
+	return &State{
+		history:      history,
+		historyIndex: 0,
+		cursor:       &Point{0, 0},
+	}
+}
+
+func (s *State) Step() bool {
+	if s.historyIndex >= len(s.history) {
+		return false
+	}
+
+	switch s.history[s.historyIndex] {
+	case 'g':
+		s.historyStart()
+	case 'i':
+		s.historyInitSection()
+	case 'm':
+		s.mark(*s.cursor)
+	case 'f':
+		s.flag(*s.cursor)
+	case 'c':
+		s.clear(*s.cursor, true)
+	case 'r':
+		s.cursorCellRight()
+	case 'l':
+		s.cursorCellLeft()
+	case 'u':
+		s.cursorCellUp()
+	case 'd':
+		s.cursorCellDown()
+	case 'R':
+		s.cursorSectionRight()
+	case 'L':
+		s.cursorSectionLeft()
+	case 'U':
+		s.cursorSectionUp()
+	case 'D':
+		s.cursorSectionDown()
+	}
+	s.historyIndex++
+
+	return true
+}
+
+func (s *State) historyStart() {
+	peek := s.historyIndex + 1
+	p, peek := s.historyPoint(peek)
+	s.sectionSize = p.X
+	s.cellsPerSection = p.Y
+	s.cells = newField(s.sectionSize * s.cellsPerSection)
+	s.sections = newField(s.sectionSize)
+	s.cursor = &Point{0, 0}
+	s.historyIndex = peek
+}
+
+func (s *State) historyInitSection() {
+	peek := s.historyIndex + 1
+	p, peek := s.historyPoint(peek)
+	segment := []byte(s.history[peek : peek+s.cellsPerSection*s.cellsPerSection])
+	for i, c := range segment {
+		curr := Point{
+			p.X*s.cellsPerSection + (i % s.cellsPerSection),
+			p.Y*s.cellsPerSection + (i / s.cellsPerSection),
+		}
+		s.cells.clear(curr, true)
+		switch c {
+		case 'x':
+			s.cells.vivify(curr)
+		case 'o':
+			s.cells.kill(curr)
+		default:
+			break
+		}
+		peek++
+	}
+	s.historyIndex = peek
+}
+
+func (s *State) historyPoint(index int) (Point, int) {
+	var x, y string
+
+	// Advance past paren
+	index++
+	for {
+		switch s.history[index] {
+		case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+			x += string(s.history[index])
+			index++
+			continue
+		}
+		break
+	}
+
+	// Advance past comma
+	index++
+	for {
+		switch s.history[index] {
+		case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+			y += string(s.history[index])
+			index++
+			continue
+		}
+		break
+	}
+
+	pX, err := strconv.Atoi(x)
+	if err != nil {
+		panic(err)
+	}
+	pY, err := strconv.Atoi(y)
+	if err != nil {
+		panic(err)
+	}
+	return Point{pX, pY}, index
+}