render.gno

  1package minichess
  2
  3import (
  4	"encoding/base64"
  5	"strconv"
  6	"strings"
  7
  8	mc "gno.land/p/g1um2pwwnx3gn8p3ryfdert8mhpu4u4up49sc9ru/minichess"
  9)
 10
 11const listLimit = 10
 12
 13// Render serves the gnoweb pages:
 14//
 15//	""               home: start a game, open challenges, recent games
 16//	"game/<id>"      a board with clickable legal moves
 17//	"player/<addr>"  a player's games
 18//	"rules"          how to enter moves and the draw rules
 19func Render(path string) string {
 20	path = strings.Trim(path, "/")
 21	switch {
 22	case path == "":
 23		return renderHome()
 24	case path == "rules":
 25		return renderRules()
 26	case strings.HasPrefix(path, "game/"):
 27		id, err := strconv.Atoi(strings.TrimPrefix(path, "game/"))
 28		if err != nil {
 29			return "# Not found\n\nBad game id."
 30		}
 31		g, ok := getGame(id)
 32		if !ok {
 33			return "# Not found\n\nGame " + strconv.Itoa(id) + " does not exist."
 34		}
 35		return renderGame(g)
 36	case strings.HasPrefix(path, "player/"):
 37		return renderPlayer(address(strings.TrimPrefix(path, "player/")))
 38	}
 39	return "# Not found\n\n[Back to Mini Chess](" + realmPath + ")"
 40}
 41
 42// actionLink builds a gnoweb link that opens a prefilled call form.
 43func actionLink(label, fn string, args ...string) string {
 44	url := realmPath + "$help&func=" + fn
 45	for i := 0; i+1 < len(args); i += 2 {
 46		url += "&" + args[i] + "=" + args[i+1]
 47	}
 48	return "[" + label + "](" + url + ")"
 49}
 50
 51func gameLink(id int) string {
 52	return "[#" + strconv.Itoa(id) + "](" + realmPath + ":game/" + strconv.Itoa(id) + ")"
 53}
 54
 55func short(a address) string {
 56	s := a.String()
 57	if len(s) > 12 {
 58		return s[:7] + "…" + s[len(s)-4:]
 59	}
 60	return s
 61}
 62
 63func playerName(g *Game, a address) string {
 64	if a == "" {
 65		if g.Mode == ModeSolo {
 66			return "🤖 bot (" + mc.Level(g.BotLevel).Name + ")"
 67		}
 68		return "_open seat_"
 69	}
 70	return "[" + short(a) + "](" + realmPath + ":player/" + a.String() + ")"
 71}
 72
 73func renderHome() string {
 74	var sb strings.Builder
 75	sb.WriteString("# ♟ Mini Chess\n\n")
 76	sb.WriteString("Classic 8×8 chess, fully on-chain — play the bot or challenge a friend. ")
 77	sb.WriteString("[Rules](" + realmPath + ":rules)\n\n")
 78
 79	sb.WriteString("## Play the bot\n\n")
 80	sb.WriteString("| Level | Play white | Play black |\n|---|---|---|\n")
 81	for lvl := mc.MinLevel; lvl <= mc.MaxLevel; lvl++ {
 82		l := strconv.Itoa(lvl)
 83		sb.WriteString("| " + mc.Level(lvl).Name + " | " +
 84			actionLink("Start as white", "NewSoloGame", "color", "white", "level", l) + " | " +
 85			actionLink("Start as black", "NewSoloGame", "color", "black", "level", l) + " |\n")
 86	}
 87
 88	sb.WriteString("\n## Play a friend\n\n")
 89	sb.WriteString("- " + actionLink("Create an open challenge", "Challenge", "opponent", "", "color", "random") + " — anyone can join\n")
 90	sb.WriteString("- " + actionLink("Challenge a specific player", "Challenge", "opponent", "g1...", "color", "white") + " — paste their address\n\n")
 91
 92	sb.WriteString("## Open challenges\n\n")
 93	open := 0
 94	openGames.ReverseIterate("", "", func(_ string, v any) bool {
 95		g := v.(*Game)
 96		side := "white"
 97		if g.White == "" {
 98			side = "black"
 99		}
100		who := "anyone"
101		if g.Invitee != "" {
102			who = playerName(g, g.Invitee)
103		}
104		sb.WriteString("- " + gameLink(g.ID) + " by " + playerName(g, g.Creator) +
105			" — you play " + side + ", for " + who + " · " +
106			actionLink("Accept", "AcceptChallenge", "gameID", strconv.Itoa(g.ID)) + "\n")
107		open++
108		return open >= listLimit
109	})
110	if open == 0 {
111		sb.WriteString("_None right now._\n")
112	}
113
114	sb.WriteString("\n## Recent games\n\n")
115	sb.WriteString("| Game | White | Black | Mode | Status |\n|---|---|---|---|---|\n")
116	n := 0
117	games.ReverseIterate("", "", func(_ string, v any) bool {
118		g := v.(*Game)
119		if g.State == StateWaiting || g.State == StateCancelled {
120			return false
121		}
122		sb.WriteString("| " + gameLink(g.ID) + " | " + playerName(g, g.White) + " | " +
123			playerName(g, g.Black) + " | " + g.Mode.String() + " | " + statusText(g) + " |\n")
124		n++
125		return n >= listLimit
126	})
127	if n == 0 {
128		sb.WriteString("| — | | | | no games yet |\n")
129	}
130	return sb.String()
131}
132
133func statusText(g *Game) string {
134	if g.State == StateActive {
135		return g.Pos.Turn.String() + " to move"
136	}
137	return g.State.String()
138}
139
140func renderGame(g *Game) string {
141	var sb strings.Builder
142	id := strconv.Itoa(g.ID)
143	sb.WriteString("# Game #" + id + "\n\n")
144	sb.WriteString("⚪ White: " + playerName(g, g.White) + " · ⚫ Black: " + playerName(g, g.Black) + " · " + g.Mode.String() + "\n\n")
145
146	// Status line.
147	switch {
148	case g.State == StateActive:
149		turn := g.Pos.Turn.String()
150		line := "**" + strings.ToUpper(turn[:1]) + turn[1:] + " to move**"
151		if g.Pos.InCheck() {
152			line += " — check!"
153		}
154		if g.DrawOffer != "" {
155			line += " · draw offered by " + playerName(g, g.DrawOffer)
156		}
157		sb.WriteString(line + "\n\n")
158	case g.State == StateWaiting:
159		sb.WriteString("**Waiting for an opponent.** " +
160			actionLink("Accept challenge", "AcceptChallenge", "gameID", id) + " · " +
161			actionLink("Cancel (creator)", "CancelChallenge", "gameID", id) + "\n\n")
162	default:
163		sb.WriteString("**Game over: " + g.State.String() + "** (" + g.Reason + ")\n\n")
164	}
165
166	sb.WriteString(renderBoardSVG(g) + "\n\n")
167
168	if g.State == StateActive {
169		sb.WriteString("### Your move\n\n")
170		if g.Mode == ModeSolo && g.playerToMove() == "" {
171			sb.WriteString("_The bot is thinking…_\n\n")
172		} else {
173			sb.WriteString(renderMoveLinks(g))
174			sb.WriteString("\n" + actionLink("Type a move", "Move", "gameID", id, "move", "") +
175				" · " + actionLink("Resign", "Resign", "gameID", id))
176			if g.Mode == ModeTwoPlayer {
177				sb.WriteString(" · " + actionLink("Offer draw", "OfferDraw", "gameID", id))
178				if g.DrawOffer != "" {
179					sb.WriteString(" · " + actionLink("Accept draw", "AcceptDraw", "gameID", id))
180				}
181			}
182			sb.WriteString("\n\n")
183		}
184	}
185
186	sb.WriteString("### Moves\n\n")
187	if len(g.Moves) == 0 {
188		sb.WriteString("_No moves yet._\n")
189	} else {
190		for i := 0; i < len(g.Moves); i += 2 {
191			sb.WriteString(strconv.Itoa(i/2+1) + ". " + g.Moves[i])
192			if i+1 < len(g.Moves) {
193				sb.WriteString(" " + g.Moves[i+1])
194			}
195			sb.WriteString("  \n")
196		}
197	}
198	sb.WriteString("\n`" + g.Pos.FEN() + "`\n\n[← All games](" + realmPath + ")\n")
199	return sb.String()
200}
201
202var glyphs = [7]string{"", "♟", "♞", "♝", "♜", "♛", "♚"}
203
204// renderMoveLinks lists legal moves grouped by the piece that moves.
205func renderMoveLinks(g *Game) string {
206	moves := g.Pos.LegalMoves()
207	if len(moves) == 0 {
208		return ""
209	}
210	var sb strings.Builder
211	id := strconv.Itoa(g.ID)
212	// Group by origin square in board order.
213	for from := 0; from < mc.NumSquares; from++ {
214		var links []string
215		for _, m := range moves {
216			if m.From == from {
217				links = append(links, actionLink(m.String()[2:], "Move", "gameID", id, "move", m.String()))
218			}
219		}
220		if len(links) == 0 {
221			continue
222		}
223		pc := g.Pos.Board[from]
224		sb.WriteString("- " + glyphs[pc.Type()] + " **" + mc.SquareName(from) + "** → " + strings.Join(links, " ") + "\n")
225	}
226	return sb.String()
227}
228
229const (
230	sqPx   = 56
231	margin = 22
232)
233
234// renderBoardSVG draws the board as an inline SVG image (white at bottom).
235func renderBoardSVG(g *Game) string {
236	size := mc.Size*sqPx + margin
237	var sb strings.Builder
238	sb.WriteString(`<svg xmlns="http://www.w3.org/2000/svg" width="` + strconv.Itoa(size) +
239		`" height="` + strconv.Itoa(size) + `" viewBox="0 0 ` + strconv.Itoa(size) + " " + strconv.Itoa(size) +
240		`" font-family="DejaVu Sans,Segoe UI Symbol,Noto Sans Symbols2,sans-serif">`)
241	sb.WriteString(`<rect width="100%" height="100%" fill="#2b2b2b"/>`)
242
243	from, to := -1, -1
244	if n := len(g.Moves); n > 0 {
245		if m, err := mc.ParseMove(g.Moves[n-1]); err == nil {
246			from, to = m.From, m.To
247		}
248	}
249	checkSq := -1
250	if g.State == StateActive || g.Reason == "checkmate" {
251		if g.Pos.InCheck() {
252			k := mc.King
253			if g.Pos.Turn == mc.Black {
254				k = -mc.King
255			}
256			for i := 0; i < mc.NumSquares; i++ {
257				if g.Pos.Board[i] == k {
258					checkSq = i
259				}
260			}
261		}
262	}
263
264	for r := 0; r < mc.Size; r++ {
265		for f := 0; f < mc.Size; f++ {
266			sq := r*mc.Size + f
267			x := margin + f*sqPx
268			y := (mc.Size - 1 - r) * sqPx
269			fill := "#eeeed2"
270			if (r+f)%2 == 0 {
271				fill = "#769656"
272			}
273			if sq == from || sq == to {
274				fill = "#f6f669"
275				if (r+f)%2 == 0 {
276					fill = "#baca2b"
277				}
278			}
279			if sq == checkSq {
280				fill = "#e05555"
281			}
282			sb.WriteString(`<rect x="` + strconv.Itoa(x) + `" y="` + strconv.Itoa(y) + `" width="` +
283				strconv.Itoa(sqPx) + `" height="` + strconv.Itoa(sqPx) + `" fill="` + fill + `"/>`)
284			pc := g.Pos.Board[sq]
285			if pc == mc.Empty {
286				continue
287			}
288			color, stroke := "#111", "#111"
289			if pc.Color() == mc.White {
290				color, stroke = "#fff", "#222"
291			}
292			sb.WriteString(`<text x="` + strconv.Itoa(x+sqPx/2) + `" y="` + strconv.Itoa(y+sqPx/2+2) +
293				`" font-size="44" text-anchor="middle" dominant-baseline="middle" fill="` + color +
294				`" stroke="` + stroke + `" stroke-width="1.2">` + glyphs[pc.Type()] + `</text>`)
295		}
296	}
297	// Coordinates.
298	for i := 0; i < mc.Size; i++ {
299		sb.WriteString(`<text x="` + strconv.Itoa(margin/2) + `" y="` + strconv.Itoa(i*sqPx+sqPx/2+5) +
300			`" font-size="14" text-anchor="middle" fill="#ddd">` + strconv.Itoa(mc.Size-i) + `</text>`)
301		sb.WriteString(`<text x="` + strconv.Itoa(margin+i*sqPx+sqPx/2) + `" y="` + strconv.Itoa(mc.Size*sqPx+16) +
302			`" font-size="14" text-anchor="middle" fill="#ddd">` + string(rune('a'+i)) + `</text>`)
303	}
304	sb.WriteString(`</svg>`)
305	return "![Board for game " + strconv.Itoa(g.ID) + "](data:image/svg+xml;base64," +
306		base64.StdEncoding.EncodeToString([]byte(sb.String())) + ")"
307}
308
309func renderPlayer(a address) string {
310	var sb strings.Builder
311	sb.WriteString("# Player " + short(a) + "\n\n")
312	v := playerGames.Get(a.String())
313	if v == nil {
314		sb.WriteString("_No games yet._\n\n[← All games](" + realmPath + ")\n")
315		return sb.String()
316	}
317	ids := v.([]int)
318	wins, losses, draws := 0, 0, 0
319	sb.WriteString("| Game | White | Black | Mode | Status |\n|---|---|---|---|---|\n")
320	for i := len(ids) - 1; i >= 0; i-- {
321		g, ok := getGame(ids[i])
322		if !ok {
323			continue
324		}
325		switch {
326		case g.State == StateDraw:
327			draws++
328		case (g.State == StateWhiteWon && g.White == a) || (g.State == StateBlackWon && g.Black == a):
329			wins++
330		case g.State == StateWhiteWon || g.State == StateBlackWon:
331			losses++
332		}
333		sb.WriteString("| " + gameLink(g.ID) + " | " + playerName(g, g.White) + " | " +
334			playerName(g, g.Black) + " | " + g.Mode.String() + " | " + statusText(g) + " |\n")
335	}
336	sb.WriteString("\n**Record:** " + strconv.Itoa(wins) + " W · " + strconv.Itoa(losses) + " L · " +
337		strconv.Itoa(draws) + " D\n\n[← All games](" + realmPath + ")\n")
338	return sb.String()
339}
340
341func renderRules() string {
342	return `# Mini Chess rules
343
344Standard chess on the normal 8×8 board, with all the usual rules:
345castling, en passant, the pawn's two-square first move and promotion.
346
347## Entering moves
348
349Moves are written as the from-square followed by the to-square:
350
351| Move | Example |
352|---|---|
353| Normal move or capture | ` + "`e2e4`, `g1f3`, `f3e5`" + ` |
354| Castling (move the king two squares) | ` + "`e1g1`" + ` (king side), ` + "`e1c1`" + ` (queen side) |
355| En passant (pawn to the empty target square) | ` + "`e5d6`" + ` |
356| Promotion (queen by default) | ` + "`e7e8`" + ` or ` + "`e7e8q`" + `; ` + "`e7e8n`" + ` for a knight, ` + "`b`" + ` bishop, ` + "`r`" + ` rook |
357
358On a game page every legal move is a link, so you rarely need to type one.
359
360## How games end
361
362- **Checkmate** wins.
363- **Stalemate**, **threefold repetition**, the **50-move rule** and **insufficient material** (king vs king, or king and one minor piece vs king) are draws and are applied automatically.
364- Two-player games can also end by **resignation** or an agreed **draw**. Bot games can be resigned.
365
366## Bot levels
367
368| Level | Searches | Typical gas per reply |
369|---|---|---|
370| easy | 1 move ahead + captures | ~10–50M |
371| medium | 2 moves ahead + captures | ~40–220M |
372| hard | 3 moves ahead + captures | ~170–370M |
373
374[← Back](` + realmPath + `)
375`
376}