bgammon/board.go

package main

import (
	"strconv"

	"code.rocketnine.space/tslocum/cview"
	"code.rocketnine.space/tslocum/fibs"
	"github.com/gdamore/tcell/v2"
)

const SpaceUnknown = -1

type GameBoard struct {
	Board *fibs.Board
	*cview.TextView

	selected [2]int

	dragFromX, dragFromY int
}

func NewGameBoard(client *fibs.Client) *GameBoard {
	b := &GameBoard{
		Board:    client.Board,
		TextView: cview.NewTextView(),
	}
	b.TextView.SetRegions(true)
	b.TextView.SetDynamicColors(true)
	b.TextView.SetToggleHighlights(true)
	b.TextView.SetHighlightedFunc(b.handleHighlight)

	b.Update()
	return b
}

func (b *GameBoard) Update() {
	b.TextView.SetBytes(b.Board.Render())
}

func (b *GameBoard) resetSelection() {
	b.selected[0] = 0
	b.selected[1] = 0
}

func (b *GameBoard) handleHighlight(added, removed, remaining []string) {
	defer b.Update()

	v := b.Board.GetIntState()

	if len(added) > 0 && len(remaining) > 0 {
		if added[0] == "space-0" || added[0] == "space-25" {
			// Deselect
			b.TextView.SetHighlightedFunc(nil)
			b.TextView.Highlight(added[0])
			b.TextView.SetHighlightedFunc(b.handleHighlight)

			b.resetSelection()
			return
		}

		from, err := strconv.Atoi(remaining[0][6:])
		if err != nil {
			b.TextView.SetHighlightedFunc(nil)
			b.TextView.Highlight(remaining[0])
			b.TextView.SetHighlightedFunc(b.handleHighlight)

			b.resetSelection()
			return
		}

		to, err := strconv.Atoi(added[0][6:])
		if err != nil {
			if added[0] == "space-off" {
				to = b.Board.PlayerHomeSpace()
			} else {
				return
			}
		}

		var spaces int
		calcFrom := from
		if to > 0 && to < 25 {
			if to >= calcFrom {
				spaces = to - calcFrom
			} else {
				spaces = calcFrom - to
			}
		}
		var mid = SpaceUnknown
		if (v[fibs.StatePlayerDice1] != v[fibs.StatePlayerDice2] && spaces*b.selected[1] == v[fibs.StatePlayerDice1]+v[fibs.StatePlayerDice2]) ||
			(v[fibs.StatePlayerDice1] == v[fibs.StatePlayerDice2] && spaces*b.selected[1] == (v[fibs.StatePlayerDice1]+v[fibs.StatePlayerDice2])*2) {
			// Prefer any move that will bar opponent
			for i := 0; i < 2; i++ {
				dice := v[fibs.StatePlayerDice1]
				if i == 2 {
					dice = v[fibs.StatePlayerDice2]
				}
				index := calcFrom + (dice * v[fibs.StateDirection])
				if index == to {
					continue
				}
				if (v[fibs.StateBoardSpace0+index] == -1 && v[fibs.StatePlayerColor] > 0) ||
					(v[fibs.StateBoardSpace0+index] == 1 && v[fibs.StatePlayerColor] < 0) {
					mid = index
					break
				}
			}
			if mid == SpaceUnknown {
				// Send any valid move
				for i := 0; i < 2; i++ {
					dice := v[fibs.StatePlayerDice1]
					if i == 2 {
						dice = v[fibs.StatePlayerDice2]
					}
					index := calcFrom + (dice * v[fibs.StateDirection])
					if index == to {
						continue
					}
					if (v[fibs.StateBoardSpace0+index] >= 0 && v[fibs.StatePlayerColor] > 0) ||
						(v[fibs.StateBoardSpace0+index] <= 0 && v[fibs.StatePlayerColor] < 0) {
						mid = index
						break
					}
				}
			}
		}

		for i := 0; i < b.selected[1]; i++ {
			if mid < 0 {
				b.Board.AddPreMove(from, to)
			} else {
				b.Board.AddPreMove(from, mid)
				b.Board.AddPreMove(mid, to)
			}
		}

		b.TextView.SetHighlightedFunc(nil)
		b.TextView.Highlight(added[0])
		b.TextView.Highlight(remaining[0])
		b.TextView.SetHighlightedFunc(b.handleHighlight)

		b.resetSelection()
	} else if len(added) > 0 {
		if added[0] == "space-off" {
			b.TextView.SetHighlightedFunc(nil)
			b.TextView.Highlight(added[0])
			b.TextView.SetHighlightedFunc(b.handleHighlight)

			b.resetSelection()
			return
		} else if (added[0] == "space-0" || added[0] == "space-25") && v[fibs.StatePlayerBar] == 0 {
			b.TextView.SetHighlightedFunc(nil)
			b.TextView.Highlight(added[0])
			b.TextView.SetHighlightedFunc(b.handleHighlight)

			b.resetSelection()
			return
		}

		index, err := strconv.Atoi(added[0][6:])
		if err == nil {
			abs := v[fibs.StateBoardSpace0+index]
			if abs < 0 {
				abs *= -1
			}
			if added[0] == "space-0" || added[0] == "space-25" {
				abs = v[fibs.StatePlayerBar]
			}

			if b.selected[1] >= abs && false { // TODO or has premove piece in space
				b.TextView.SetHighlightedFunc(nil)
				b.TextView.Highlight(added[0])
				b.TextView.SetHighlightedFunc(b.handleHighlight)
				return
			}

			b.selected[0] = index
			b.selected[1]++
		}
	} else if len(removed) > 0 {
		index, err := strconv.Atoi(removed[0][6:])
		if err == nil {
			abs := v[fibs.StateBoardSpace0+index]
			if abs < 0 {
				abs *= -1
			}
			if removed[0] == "space-0" || removed[0] == "space-25" {
				abs = v[fibs.StatePlayerBar]
			}

			if b.selected[1] < abs {
				b.selected[0] = index
				b.selected[1]++
			}

			b.TextView.SetHighlightedFunc(nil)
			b.TextView.Highlight(removed[0])
			b.TextView.SetHighlightedFunc(b.handleHighlight)
		}
	}
}

// MouseHandler returns the mouse handler for this primitive.
func (b *GameBoard) MouseHandler() func(action cview.MouseAction, event *tcell.EventMouse, setFocus func(p cview.Primitive)) (consumed bool, capture cview.Primitive) {
	return b.WrapMouseHandler(func(action cview.MouseAction, event *tcell.EventMouse, setFocus func(p cview.Primitive)) (consumed bool, capture cview.Primitive) {
		x, y := event.Position()
		if !b.InRect(x, y) {
			return false, nil
		}

		switch action {
		case cview.MouseLeftDown:
			b.dragFromX, b.dragFromY = x, y
		case cview.MouseLeftUp:
			if b.dragFromX != x || b.dragFromY != y {
				app.QueueUpdateDraw(func() {
					// Simulate click event at start of drag
					fromEvent := tcell.NewEventMouse(b.dragFromX, b.dragFromY, tcell.ButtonPrimary, event.Modifiers())
					b.TextView.MouseHandler()(cview.MouseLeftClick, fromEvent, setFocus)
					consumed, _ = b.TextView.MouseHandler()(cview.MouseLeftClick, event, setFocus)
					if consumed {
						// Succeeded
						return
					}
					// Failed, undo
					b.TextView.MouseHandler()(cview.MouseLeftClick, fromEvent, setFocus)
				})
			}
		case cview.MouseRightClick:
			b.TextView.SetHighlightedFunc(nil)
			h := b.GetHighlights()
			for i := range h {
				b.Highlight(h[i])
			}
			b.TextView.SetHighlightedFunc(b.handleHighlight)

			b.resetSelection()

			b.Update()

			consumed = true
			return
		}

		return b.TextView.MouseHandler()(action, event, setFocus)
	})
}