///|
/// playground 引擎会话协议（纯 MoonBit，文本进出，无任何宿主依赖）。
///
/// 文本协议：首行为操作名，其后为载荷：
///
/// - `render\n<声明文本>` → 解析 + Agent 硬门槛 + SVG
/// - `human_move\n\n\n\n<声明文本>` → 人类策略（结构硬 / 视觉软）
///
/// 会话无内部状态：声明文本本身就是状态。任何宿主（CLI、编辑器、未来的
/// 画布进程）都可以用同一协议驱动引擎，引擎对其一无所知。
pub fn version() -> String {
"moonviz-playground 0.1.0"
}
///|
/// Agent / 渲染入口：违规整体拒绝
pub fn handle(request : String) -> String {
handle_with_gate(request, @core.AgentGate)
}
///|
/// 人类入口：结构硬、视觉软；成功携带视觉债
pub fn handle_human(request : String) -> String {
handle_with_gate(request, @core.HumanGate)
}
///|
fn handle_with_gate(request : String, default_gate : @core.Gate) -> String {
let lines = split_first_line(request)
match lines.op {
"render" =>
match @decl.parse_decl(lines.rest) {
Err(e) => parse_error_response(e)
Ok(page) => {
let violations = page.check()
match @core.decide(default_gate, violations) {
@core.Reject(blocking) => block_response("hard_block", blocking)
@core.Allow(_) =>
ok_response(page.render(), page.to_decl_text(), 0, [])
}
}
}
"human_move" =>
match move_payload(lines.rest) {
Err(e) => error_payload("protocol_error", e)
Ok(mv) =>
match @decl.parse_decl(mv.rest) {
Err(e) => parse_error_response(e)
Ok(page) => {
let moved = page.move_node(id=mv.id, x=mv.x, y=mv.y)
match moved {
Err(msg) => error_payload("unknown_node", msg)
Ok(_) => {
let violations = page.check()
match @core.decide(@core.HumanGate, violations) {
@core.Reject(blocking) =>
block_response("structural_block", blocking)
@core.Allow(debt) =>
ok_response(
page.render(),
page.to_decl_text(),
debt.length(),
debt,
)
}
}
}
}
}
}
other => error_payload("unknown_op", other)
}
}
///|
struct FirstLine {
op : String
rest : String
}
///|
fn split_first_line(request : String) -> FirstLine {
let mut idx : Int? = None
let mut pos = 0
for c in request.iter() {
match idx {
Some(_) => ()
None => if c == '\n' { idx = Some(pos) } else { pos = pos + 1 }
}
}
match idx {
Some(i) =>
{
op: trim_line(request.substring(start=0, end=i)),
rest: request.substring(start=i + 1),
}
None => { op: trim_line(request), rest: "", }
}
}
///|
struct MovePayload {
id : String
x : Double
y : Double
rest : String
}
///|
/// human_move 载荷：第 1..3 行 = id / x / y，其余行 = 当前声明文本
fn move_payload(rest : String) -> Result[MovePayload, String] {
let lines : Array[String] = Array::new()
let mut buf = StringBuilder::new()
for c in rest.iter() {
if c == '\n' {
lines.push(buf.to_string())
buf = StringBuilder::new()
} else {
buf.write_char(c)
}
}
lines.push(buf.to_string())
if lines.length() < 4 {
return Err("human_move 需要 4 段：id / x / y / 声明文本")
}
let x : Double = match parse_num(lines[1]) {
Some(v) => v
None => return Err("无法解析 x 数值")
}
let y : Double = match parse_num(lines[2]) {
Some(v) => v
None => return Err("无法解析 y 数值")
}
Ok({ id: trim_line(lines[0]), x, y, rest: join_from(lines, 3), })
}
///|
fn join_from(lines : Array[String], from : Int) -> String {
let sb = StringBuilder::new()
for i in from.. from {
sb.write_char('\n')
}
sb.write_string(lines[i])
}
sb.to_string()
}
///|
fn trim_line(s : String) -> String {
match s.find_by(fn(c) { c != ' ' }) {
None => ""
Some(a) => {
let mut b = s.length() - 1
let mut end = a
let mut running = true
while b >= a && running {
match s.get_char(b) {
Some(c) =>
if c != ' ' {
end = b
running = false
} else {
b = b - 1
}
None => running = false
}
}
s.substring(start=a, end=end + 1)
}
}
}
///|
/// 正/负整数与小数（坐标域）
fn parse_num(s : String) -> Double? {
let t : String = trim_line(s)
if t.length() == 0 {
return None
}
let is_neg : Bool = t.get_char(0) == Some('-')
let body : String = if is_neg { t.substring(start=1) } else { t }
let dot : Int? = body.find(".")
let intp : String = match dot {
Some(i) => body.substring(start=0, end=i)
None => body
}
let fracp : String = match dot {
Some(i) => body.substring(start=i + 1)
None => "0"
}
if intp.length() == 0 && body.find(".") != Some(0) {
return None
}
let mut acc = 0
for c in intp.iter() {
let code = c.to_int()
if code < 48 || code > 57 {
return None
}
acc = acc * 10 + (code - 48)
}
let mut frac = 0.0
let mut scale = 0.1
for c in fracp.iter() {
let code = c.to_int()
if code < 48 || code > 57 {
return None
}
frac = frac + (code - 48).to_double() * scale
scale = scale / 10.0
}
let v = acc.to_double() + frac
Some(if is_neg { -v } else { v })
}
// ---------------------------------------------------------------------------
// 响应序列化（JSON 文本）
// ---------------------------------------------------------------------------
///|
fn join_comma(parts : Array[String]) -> String {
let sb = StringBuilder::new()
for i in 0.. 0 {
sb.write_string(",")
}
sb.write_string(parts[i])
}
sb.to_string()
}
///|
fn ok_response(
svg : String,
decl : String,
debt : Int,
violations : Array[@core.Violation],
) -> String {
let parts : Array[String] = Array::new()
for v in violations.iter() {
parts.push(v.to_json())
}
"{\n \"ok\": true,\n \"debt\": \{debt},\n \"violations\": [\{join_comma(parts)}],\n \"decl\": \"\{@core.json_escape(decl)}\",\n \"svg\": \"\{@core.json_escape(svg)}\"\n}"
}
///|
fn parse_error_response(e : @decl.DeclParseError) -> String {
"{\"error\": \"parse_error\", \"line\": \{e.line}, \"message\": \"\{@core.json_escape(e.message)}\"}"
}
///|
fn error_payload(kind : String, detail : String) -> String {
"{\"error\": \"\{kind}\", \"detail\": \"\{@core.json_escape(detail)}\"}"
}
///|
fn block_response(kind : String, blocking : Array[@core.Violation]) -> String {
let parts : Array[String] = Array::new()
for v in blocking.iter() {
parts.push(v.to_json())
}
"{\"error\": \"\{kind}\", \"violations\": [\{join_comma(parts)}]}"
}