#!/usr/bin/env python3
"""lang_verify.py: the independent verifier of joule-ui's line language (SPEC §11).

Written from SPEC.md §4 and §11 alone, sharing no code with the reference
implementation (joule-ui-rs/crates/joule-ui-lang). It recomputes every case of the
pack in conformance/lang/v1/ (L1 statements, L2 ingest, L3 streaming, L4 the
canonical form, L5 refusals) from the case's input and the pack's library, and
compares what it gets with what the pack states. Errors are compared without
their messages, which are not normative.

    python3 -I lang_verify.py [<pack dir>]            verify the pack
    python3 -I lang_verify.py --mutations [<dir>]     show that changed vectors are refused

Exit status: 0 when every case agrees (or, with --mutations, when every mutation is
caught); 1 otherwise. Standard library only.
"""
from decimal import Decimal
import hashlib
import json
import os
import sys

HERE = os.path.dirname(os.path.abspath(__file__))
DEFAULT_PACK = os.path.join(HERE, "lang", "v1")

# ---------------------------------------------------------------------------
# §4 validation

def ptype(v):
    return v["type"]


def validate(w, reg, path="$"):
    """SPEC §4: every error of the tree, pre-order."""
    errs = []
    s = reg.get(w["name"])
    if s is None:
        errs.append({"kind": "unknown_widget", "name": w["name"], "path": path})
        return errs
    props = w.get("props", {})
    for p in sorted(s["props"]):
        if s["props"][p].get("required") and p not in props:
            errs.append({"kind": "missing_prop", "prop": p, "path": path})
    for p in sorted(props):
        if p in s["props"]:
            want = s["props"][p]["ty"]
            if want != "any" and want != ptype(props[p]):
                errs.append({"kind": "wrong_prop_type", "prop": p, "path": path})
        elif not s.get("allow_extra_props"):
            errs.append({"kind": "extra_prop", "prop": p, "path": path})
    ch = s["children"]
    for i, c in enumerate(w.get("children", [])):
        cp = "%s.children[%d]" % (path, i)
        kind = ch["kind"]
        ok = kind == "any" or (kind == "only_of" and c["name"] in ch["value"])
        if not ok:
            errs.append({"kind": "disallowed_child", "child": c["name"], "path": cp})
        errs.extend(validate(c, reg, cp))
    return errs


# ---------------------------------------------------------------------------
# §11.1 source text

MARKER = "]]>openui:"
FENCE = "```"


def strip_comments(t):
    out = []
    quote = None
    i = 0
    n = len(t)
    while i < n:
        c = t[i]
        if quote is not None:
            out.append(c)
            if c == "\\":
                if i + 1 < n:
                    out.append(t[i + 1])
                    i += 2
                    continue
            elif c == quote:
                quote = None
            i += 1
            continue
        if c in "\"'":
            quote = c
            out.append(c)
            i += 1
            continue
        if c == "#" or (c == "/" and i + 1 < n and t[i + 1] == "/"):
            while i < n and t[i] != "\n":
                i += 1
            continue
        out.append(c)
        i += 1
    return "".join(out)


def prepare(source):
    text = source.replace("\r\n", "\n")
    lines = [(i + 1, l) for i, l in enumerate(text.split("\n"))]
    if any(l.startswith(MARKER) for _, l in lines):
        kept = []
        content = False
        for n, l in lines:
            if l.startswith(MARKER):
                content = l[len(MARKER):].startswith("content")
                continue
            if content:
                kept.append((n, l))
        lines = kept
    if any(l.startswith(FENCE) for _, l in lines):
        kept = []
        inside = False
        dq = False
        skip = False
        for n, l in lines:
            if not inside:
                if l.startswith(FENCE):
                    inside, dq, skip = True, False, False
                continue
            if not dq and l.startswith(FENCE):
                inside = False
                continue
            kept.append((n, l))
            for c in l:
                if skip:
                    skip = False
                elif dq and c == "\\":
                    skip = True
                elif c == '"':
                    dq = not dq
            skip = False
        lines = kept
    numbers = [n for n, _ in lines]
    joined = strip_comments("\n".join(l for _, l in lines))
    ws = " \t\n\r"
    lead = len(joined) - len(joined.lstrip(ws))
    numbers = numbers[joined[:lead].count("\n"):]
    body = joined.strip(ws)
    numbers = numbers[: len(body.split("\n"))]
    return body, numbers


# ---------------------------------------------------------------------------
# §11.2 lexing

def is_start(c):
    return ("a" <= c <= "z") or ("A" <= c <= "Z") or c == "_"


def is_part(c):
    return is_start(c) or ("0" <= c <= "9")


def is_digit(c):
    return "0" <= c <= "9"


VALUE_KINDS = {"ident", "state", "str", "num", "badnum", "true", "false", "null"}


def ends_value(tok):
    return tok["k"] in VALUE_KINDS or (tok["k"] == "p" and tok["v"] in (")", "]"))


def decode_dq(raw):
    try:
        v = json.loads('"' + raw + '"')
    except ValueError:
        return raw
    if any(0xD800 <= ord(ch) <= 0xDFFF for ch in v):
        return raw
    return v


def decode_sq(raw):
    out = []
    i = 0
    while i < len(raw):
        c = raw[i]
        if c != "\\":
            out.append(c)
            i += 1
            continue
        if i + 1 < len(raw):
            e = raw[i + 1]
            out.append("\n" if e == "n" else "\t" if e == "t" else e)
        i += 2
    return "".join(out)


TWO = ("==", "!=", ">=", "<=", "&&", "||")
ONE = {"=": "=", ">": ">", "<": "<", "+": "+", "-": "-", "*": "*", "/": "/", "%": "%", "&": "&&", "|": "||",
       "!": "!", "?": "?", ":": ":", ".": ".", ",": ",", "(": "(", ")": ")", "[": "[", "]": "]", "{": "{", "}": "}"}


def lex(t):
    toks = []
    i, n, line = 0, len(t), 0

    def add(k, v=None, start=None, open_=False):
        toks.append({"k": k, "v": v, "line": line if start is None else start, "open": open_})

    while i < n:
        c = t[i]
        if c in " \t":
            i += 1
        elif c == "\n":
            add("nl")
            line += 1
            i += 1
        elif c in "\"'":
            start = line
            j = i + 1
            closed = False
            while j < n:
                d = t[j]
                if d == "\\":
                    if j + 1 < n and t[j + 1] == "\n":
                        line += 1
                    j += 2
                    continue
                if d == "\n":
                    line += 1
                if d == c:
                    closed = True
                    break
                j += 1
            raw = t[i + 1: min(j, n)]
            if not closed:
                trailing = len(raw) - len(raw.rstrip("\\"))
                if trailing % 2 == 1:
                    raw += "\\"
            add("str", decode_dq(raw) if c == '"' else decode_sq(raw), start, not closed)
            i = j + 1 if closed else n
        elif c in "$@" and i + 1 < n and is_start(t[i + 1]):
            j = i + 1
            while j < n and is_part(t[j]):
                j += 1
            if c == "$":
                add("state", t[i:j])
            else:
                add("at", t[i + 1:j])
            i = j
        elif is_start(c):
            j = i
            while j < n and is_part(t[j]):
                j += 1
            w = t[i:j]
            if w in ("true", "false", "null"):
                add(w, w)
            else:
                add("ident", w)
            i = j
        elif is_digit(c) or (c == "-" and i + 1 < n and is_digit(t[i + 1]) and not (toks and ends_value(toks[-1]))):
            j = i + 1 if c == "-" else i
            while j < n and is_digit(t[j]):
                j += 1
            if j + 1 < n and t[j] == "." and is_digit(t[j + 1]):
                j += 1
                while j < n and is_digit(t[j]):
                    j += 1
            bad = False
            if j < n and t[j] in "eE":
                j += 1
                if j < n and t[j] in "+-":
                    j += 1
                d0 = j
                while j < n and is_digit(t[j]):
                    j += 1
                bad = j == d0
            text = t[i:j]
            if bad:
                add("badnum", text)
            else:
                toks.append({"k": "num", "v": float(text), "text": text, "line": line, "open": False})
            i = j
        else:
            if t[i:i + 2] in TWO:
                add("p", t[i:i + 2])
                i += 2
                continue
            if c in ONE:
                add("p", ONE[c])
            i += 1
    return toks


# ---------------------------------------------------------------------------
# §11.3 statements

def is_p(tok, v):
    return tok["k"] == "p" and tok["v"] == v


def split(toks, finished):
    out = []
    pos, n = 0, len(toks)
    while pos < n:
        while pos < n and toks[pos]["k"] == "nl":
            pos += 1
        if pos >= n:
            break
        t0 = toks[pos]
        if t0["k"] not in ("ident", "state") or pos + 1 >= n or not is_p(toks[pos + 1], "="):
            while pos < n and toks[pos]["k"] != "nl":
                pos += 1
            continue
        name, state, line = t0["v"], t0["k"] == "state", t0["line"]
        pos += 2
        expr = []
        depth = 0
        tern = []  # [in second branch, has operand]
        complete = finished
        boundary = False
        while pos < n:
            t = toks[pos]
            if t["k"] == "nl":
                if depth == 0 and not tern:
                    peek = pos + 1
                    while peek < n and toks[peek]["k"] == "nl":
                        peek += 1
                    if peek < n and is_p(toks[peek], "?"):
                        pos += 1
                        continue
                    boundary = True
                    if peek < n:
                        complete = True
                    break
                pos += 1
                continue
            operand = False
            if t["k"] == "p" and t["v"] in "([{":
                depth += 1
            elif t["k"] == "p" and t["v"] in ")]}":
                if depth > 0:
                    depth -= 1
                    operand = depth == 0
            elif is_p(t, "?") and depth == 0:
                tern.append([False, False])
            elif is_p(t, ":") and depth == 0:
                if tern and not tern[-1][0]:
                    tern[-1] = [True, False]
            elif t["k"] in VALUE_KINDS:
                operand = depth == 0
            if operand and tern:
                tern[-1][1] = True
                if tern[-1][0]:
                    tern.pop()
            expr.append(t)
            pos += 1
        opened = (not boundary) and (depth > 0 or (bool(expr) and expr[-1]["open"]))
        out.append({"name": name, "state": state, "line": line, "toks": expr, "complete": complete, "open": opened})
    return out


# ---------------------------------------------------------------------------
# §11.4 expressions

def close(toks):
    out, stack = [], []
    pairs = {"(": ")", "[": "]", "{": "}"}
    for t in toks:
        if t["k"] == "p" and t["v"] in pairs:
            stack.append(pairs[t["v"]])
        elif t["k"] == "p" and t["v"] in ")]}":
            if stack and stack[-1] == t["v"]:
                stack.pop()
            else:
                continue
        out.append(t)
    line = toks[-1]["line"] if toks else 0
    while stack:
        out.append({"k": "p", "v": stack.pop(), "line": line, "open": False})
    return out


class Stop(Exception):
    def __init__(self, line):
        self.line = line


class P:
    def __init__(self, toks):
        self.t, self.i = toks, 0

    def peek(self):
        return self.t[self.i] if self.i < len(self.t) else None

    def at(self, v):
        x = self.peek()
        return x is not None and is_p(x, v)

    def line(self):
        x = self.peek()
        if x is None:
            x = self.t[-1] if self.t else None
        return x["line"] if x else 0

    def stop(self):
        raise Stop(self.line())

    def expect(self, v):
        if not self.at(v):
            self.stop()
        self.i += 1

    def ternary(self):
        c = self.binary(0)
        if self.at("?"):
            self.i += 1
            a = self.ternary()
            self.expect(":")
            b = self.ternary()
            return {"e": "ternary", "line": c["line"]}
        return c

    LEVELS = [("||",), ("&&",), ("==", "!="), (">", "<", ">=", "<="), ("+", "-"), ("*", "/", "%")]

    def binary(self, lvl):
        if lvl == len(self.LEVELS):
            return self.unary()
        left = self.binary(lvl + 1)
        while True:
            x = self.peek()
            if x is None or x["k"] != "p" or x["v"] not in self.LEVELS[lvl]:
                return left
            op = x["v"]
            self.i += 1
            self.binary(lvl + 1)
            left = {"e": "binary", "op": op, "line": left["line"]}

    def unary(self):
        if self.at("!") or self.at("-"):
            line = self.line()
            self.i += 1
            self.unary()
            return {"e": "unary", "line": line}
        return self.postfix()

    def postfix(self):
        e = self.primary()
        while True:
            if self.at("."):
                self.i += 1
                self.key()
                e = {"e": "member", "line": e["line"]}
            elif self.at("["):
                self.i += 1
                self.ternary()
                self.expect("]")
                e = {"e": "index", "line": e["line"]}
            else:
                return e

    def key(self):
        x = self.peek()
        if x is None:
            self.stop()
        self.i += 1
        k = x["k"]
        if k in ("ident", "str"):
            return x["v"]
        if k == "state":
            return x["v"][1:]
        if k == "num":
            return x["text"]
        if k == "badnum":
            return x["v"]
        if k in ("true", "false", "null"):
            return k
        if k == "at":
            return "@" + x["v"]
        return "?"

    def items(self, closer):
        v = []
        while True:
            while self.at(","):
                self.i += 1
            if self.at(closer):
                self.i += 1
                return v
            if self.peek() is None:
                self.stop()
            v.append(self.ternary())

    def primary(self):
        x = self.peek()
        if x is None:
            self.stop()
        line = x["line"]
        k = x["k"]
        self.i += 1
        if k == "str":
            return {"e": "str", "v": x["v"], "line": line}
        if k == "num":
            return {"e": "num", "v": x["v"], "line": line}
        if k == "badnum":
            self.i -= 1
            self.stop()
        if k in ("true", "false"):
            return {"e": "bool", "v": k == "true", "line": line}
        if k == "null":
            return {"e": "null", "line": line}
        if k == "p" and x["v"] == "[":
            return {"e": "list", "items": self.items("]"), "line": line}
        if k == "p" and x["v"] == "{":
            entries = []
            while True:
                while self.at(","):
                    self.i += 1
                if self.at("}"):
                    self.i += 1
                    break
                if self.peek() is None:
                    self.stop()
                kk = self.key()
                self.expect(":")
                entries.append((kk, self.ternary()))
            return {"e": "object", "entries": entries, "line": line}
        if k == "p" and x["v"] == "(":
            e = self.ternary()
            self.expect(")")
            return e
        if k == "ident":
            if self.at("(") and "A" <= x["v"][0] <= "Z":
                self.i += 1
                return {"e": "call", "at": False, "name": x["v"], "args": self.items(")"), "line": line}
            return {"e": "ref", "name": x["v"], "line": line}
        if k == "at":
            self.expect("(")
            return {"e": "call", "at": True, "name": x["v"], "args": self.items(")"), "line": line}
        if k == "state":
            if self.at("="):
                self.i += 1
                self.ternary()
                return {"e": "assign", "line": line}
            return {"e": "state", "name": x["v"], "line": line}
        self.i -= 1
        self.stop()


def parse_tokens(toks):
    if not toks:
        raise Stop(None)
    p = P(toks)
    e = p.ternary()
    if p.i < len(toks):
        p.stop()
    return e


# ---------------------------------------------------------------------------
# §11.5 into a joule-ui tree

BUILTINS = {"Count", "First", "Last", "Sum", "Avg", "Min", "Max", "Filter", "Sort", "Round", "Abs", "Floor", "Ceil", "Each"}
STATE_ACTIONS = {"Set", "Reset", "Run"}


def T(v):
    return {"type": "text", "value": v}


class Ingest:
    def __init__(self, lib, finished, lines):
        self.reg = lib["widgets"]
        self.lib = lib
        self.finished = finished
        self.lines = lines
        self.errors = []
        self.unresolved = set()
        self.visited = set()
        self.resolving = []
        self.occ = {}
        self.binds = {}

    def src(self, line):
        return self.lines[line] if 0 <= line < len(self.lines) else 0

    def err(self, stmt, line, code, component=None, prop=None):
        self.errors.append({"line": self.src(line), "statement": stmt, "code": code, "component": component, "prop": prop, "warning": False})

    def reference(self, name):
        b = self.binds.get(name)
        if b is None or name in self.resolving:
            self.unresolved.add(name)
            return ("unresolved",)
        if b["kind"] != "value":
            return ("refused",)
        self.visited.add(name)
        self.occ[name] = self.occ.get(name, 0) + 1
        key = name if self.occ[name] == 1 else "%s#%d" % (name, self.occ[name])
        self.resolving.append(name)
        v = self.eval(b["expr"], name, key)
        self.resolving.pop()
        return v

    def eval(self, e, stmt, key):
        k = e["e"]
        if k == "str":
            return ("data", T(e["v"]))
        if k == "num":
            return ("data", {"type": "number", "value": e["v"]})
        if k == "bool":
            return ("data", {"type": "bool", "value": e["v"]})
        if k == "null":
            return ("null",)
        if k == "ref":
            return self.reference(e["name"])
        if k in ("state", "unary", "binary", "ternary", "member", "index", "assign"):
            self.err(stmt, e["line"], "not-declarative")
            return ("refused",)
        if k == "list":
            return ("list", [self.eval(it, stmt, "%s/%d" % (key, i)) for i, it in enumerate(e["items"])])
        if k == "object":
            return ("object", [(kk, self.eval(v, stmt, "%s/%s" % (key, kk))) for kk, v in e["entries"]])
        # a call
        name, args = e["name"], e["args"]
        if not e["at"]:
            if name in ("Query", "Mutation"):
                self.err(stmt, e["line"], "inline-reserved")
                return ("refused",)
            if name == "Action":
                return self.action_list(args, stmt, e["line"], key)
            return self.build(name, args, e["line"], stmt, key)
        if name in BUILTINS or name in STATE_ACTIONS:
            self.err(stmt, e["line"], "not-declarative")
            return ("refused",)
        if name == "Action":
            return self.action_list(args, stmt, e["line"], key)
        items, not_yet, refused = [], False, False
        for i, a in enumerate(args):
            r = self.data(self.eval(a, stmt, "%s/%d" % (key, i)), stmt, a["line"], True)
            if r == "not-yet":
                not_yet = True
            elif r == "refused":
                refused = True
            else:
                items.append(r)
        if refused:
            return ("refused",)
        if not_yet:
            return ("held",)
        payload = None if not items else items[0] if len(items) == 1 else {"type": "list", "value": items}
        return ("action", {"type": "action", "value": {"id": name, "payload": payload}})

    def action_list(self, args, stmt, line, key):
        if len(args) == 1 and args[0]["e"] == "list" and len(args[0]["items"]) == 1:
            one = args[0]["items"][0]
            v = self.eval(one, stmt, key + "/0")
            if v[0] == "action":
                return v
            if v[0] in ("unresolved", "held"):
                return ("held",)
            if v[0] == "refused":
                return ("refused",)
            self.err(stmt, one["line"], "type-mismatch")
            return ("refused",)
        self.err(stmt, line, "not-declarative")
        return ("refused",)

    def data(self, v, stmt, line, keep_null):
        """A value placed as data: a PropValue, "not-yet" or "refused"."""
        k = v[0]
        if k in ("data", "action"):
            return v[1]
        if k == "null":
            return {"type": "null"} if keep_null else "not-yet"
        if k == "list":
            out = []
            for it in v[1]:
                r = self.data(it, stmt, line, True)
                if isinstance(r, dict):
                    out.append(r)
            return {"type": "list", "value": out}
        if k == "object":
            out = {}
            for kk, it in v[1]:
                r = self.data(it, stmt, line, True)
                if isinstance(r, dict):
                    out[kk] = r
            return {"type": "object", "value": out}
        if k == "widget":
            self.err(stmt, line, "type-mismatch", v[1]["name"])
            return "refused"
        if k in ("unresolved", "held"):
            return "not-yet"
        return "refused"

    def build(self, name, args, line, stmt, key):
        s = self.reg.get(name)
        if s is None:
            self.err(stmt, line, "unknown-component", name)
            return ("refused",)
        order = s["positional"]
        if len(args) > len(order):
            self.err(stmt, args[len(order)]["line"], "excess-args", name)
        props, absent, children = {}, {}, []
        for slot, arg in zip(order, args):
            if slot == "children":
                v = self.eval(arg, stmt, key)
                if v[0] == "list":
                    for it in v[1]:
                        if it[0] == "widget":
                            children.append((it[1], it[2]))
                        elif it[0] in ("unresolved", "held", "null", "refused"):
                            pass
                        else:
                            self.err(stmt, arg["line"], "type-mismatch", name, "children")
                elif v[0] in ("null", "unresolved", "held", "refused"):
                    pass
                else:
                    self.err(stmt, arg["line"], "type-mismatch", name, "children")
                continue
            v = self.eval(arg, stmt, "%s/%s" % (key, slot))
            if v[0] == "null":
                absent[slot] = "null"
            elif v[0] in ("unresolved", "held"):
                absent[slot] = "not-yet"
            elif v[0] == "refused":
                absent[slot] = "refused"
            elif v[0] == "widget":
                self.err(stmt, arg["line"], "type-mismatch", name, slot)
                absent[slot] = "refused"
            else:
                r = self.data(v, stmt, arg["line"], False)
                if isinstance(r, dict):
                    props[slot] = r
                else:
                    absent[slot] = r
        w = {"name": name, "props": props}
        if children:
            w["children"] = [c[0] for c in children]
        child_nodes = [c[1] for c in children]
        while True:
            errs = validate(w, self.reg)
            if not errs:
                break
            if not self.finished and any(x["kind"] == "missing_prop" and x["path"] == "$" and absent.get(x["prop"]) == "not-yet" for x in errs):
                return ("held",)
            drop = False
            drop_children = []
            before = len(w["props"])
            for x in errs:
                kind, path = x["kind"], x["path"]
                if kind == "missing_prop" and path == "$":
                    why = absent.get(x["prop"])
                    if why == "null":
                        self.err(stmt, line, "null-required", name, x["prop"])
                    elif why != "refused":
                        self.err(stmt, line, "missing-required", name, x["prop"])
                    drop = True
                elif kind == "wrong_prop_type" and path == "$":
                    self.err(stmt, line, "type-mismatch", name, x["prop"])
                    if s["props"][x["prop"]].get("required"):
                        drop = True
                    else:
                        del w["props"][x["prop"]]
                elif kind == "extra_prop" and path == "$":
                    self.err(stmt, line, "type-mismatch", name, x["prop"])
                    del w["props"][x["prop"]]
                elif kind == "disallowed_child":
                    idx = child_index(path)
                    if idx is None:
                        drop = True
                        continue
                    first = child_nodes[idx][0] if idx < len(child_nodes) and child_nodes[idx] else None
                    self.errors.append({"line": first["line"] if first and first["line"] > 0 else self.src(line),
                                        "statement": first["statement"] if first else stmt,
                                        "code": "disallowed-child", "component": x["child"], "prop": None, "warning": False})
                    drop_children.append(idx)
                else:
                    drop = True
            if drop:
                return ("refused",)
            drop_children = sorted(set(drop_children))
            changed = bool(drop_children) or len(w["props"]) != before
            for i in reversed(drop_children):
                del w["children"][i]
                del child_nodes[i]
            if "children" in w and not w["children"]:
                del w["children"]
            if not changed:
                return ("refused",)
        nodes = [{"key": key, "line": self.src(line), "statement": stmt}]
        for cn in child_nodes:
            nodes.extend(cn)
        return ("widget", w, nodes)


def child_index(path):
    pre = "$.children["
    if not path.startswith(pre) or not path.endswith("]"):
        return None
    mid = path[len(pre):-1]
    return int(mid) if mid.isdigit() else None


def snapshot(lib, text, finished):
    body, lines = prepare(text)
    toks = lex(body)
    raws = split(toks, finished)
    incomplete = bool(raws) and raws[-1]["open"]
    ing = Ingest(lib, finished, lines)
    src = ing.src
    errors, statements, binds = [], [], {}
    for order, r in enumerate(raws):
        tk = close(r["toks"]) if r["open"] else r["toks"]
        line = src(r["line"])
        try:
            e = parse_tokens(tk)
        except Stop as stop:
            if r["complete"]:
                at = line if stop.line is None or not tk else src(stop.line)
                errors.append({"line": at, "statement": r["name"], "code": "syntax", "component": None, "prop": None, "warning": False})
                statements.append({"name": r["name"], "line": line, "kind": "syntax", "complete": True})
            continue
        if e["e"] == "call" and not e["at"] and e["name"] == "Query":
            kind = "query"
        elif e["e"] == "call" and not e["at"] and e["name"] == "Mutation":
            kind = "mutation"
        elif r["state"]:
            kind = "state"
        else:
            kind = "value"
        statements.append({"name": r["name"], "line": line, "kind": kind, "complete": r["complete"]})
        if r["complete"] and kind != "value":
            errors.append({"line": line, "statement": r["name"], "code": "not-declarative", "component": None, "prop": None, "warning": False})
        prev = binds.get(r["name"])
        if prev is not None and prev["complete"] and not r["complete"] and r["open"]:
            continue
        binds[r["name"]] = {"line": line, "complete": r["complete"], "kind": kind, "expr": e, "order": order}
    ing.binds = binds
    entry = None
    if "root" in binds:
        entry = ("root", False)
    elif lib.get("root"):
        vals = sorted((b["order"], n) for n, b in binds.items() if b["kind"] == "value")
        for _, n in vals:
            ex = binds[n]["expr"]
            if ex["e"] == "call" and not ex["at"] and ex["name"] == lib["root"]:
                entry = (n, True)
                break
    tree, nodes = None, []
    if entry:
        v = ing.reference(entry[0])
        if v[0] == "widget":
            tree, nodes = v[1], v[2]
    errors.extend(ing.errors)
    if finished:
        if entry is None:
            code = "parse-failed" if not statements and body != "" else "no-root"
            errors.append({"line": 0, "statement": "", "code": code, "component": None, "prop": None, "warning": False})
        else:
            line = binds[entry[0]]["line"]
            if tree is None:
                errors.append({"line": line, "statement": entry[0], "code": "no-root", "component": None, "prop": None, "warning": False})
            elif entry[1]:
                errors.append({"line": line, "statement": entry[0], "code": "no-root", "component": None, "prop": None, "warning": True})
    if not finished:
        errors = [x for x in errors if x["statement"] not in binds or binds[x["statement"]]["complete"]]

    def opt(v):
        return (0, "") if v is None else (1, v)

    def ekey(x):
        return (x["line"], x["statement"], x["code"], opt(x["component"]), opt(x["prop"]), x["warning"])

    errors.sort(key=ekey)
    kept = []
    for x in errors:
        if not kept or ekey(kept[-1]) != ekey(x):
            kept.append(x)
    orphans = sorted(n for n, b in binds.items() if b["kind"] == "value" and n not in ing.visited) if entry else []
    if tree is not None and validate(tree, ing.reg):
        tree, nodes = None, []
    return {"tree": tree, "nodes": nodes, "errors": kept, "unresolved": sorted(ing.unresolved), "orphans": orphans,
            "incomplete": incomplete, "statements": statements}


def stated(s):
    """A snapshot as the pack states it (§11.9)."""
    errs = []
    for x in s["errors"]:
        e = {"line": x["line"], "statement": x["statement"], "code": x["code"]}
        if x["component"] is not None:
            e["component"] = x["component"]
        if x["prop"] is not None:
            e["prop"] = x["prop"]
        if x["warning"]:
            e["warning"] = True
        errs.append(e)
    return {"tree": s["tree"], "nodes": s["nodes"], "errors": errs, "unresolved": s["unresolved"],
            "orphans": s["orphans"], "incomplete": s["incomplete"]}


class Stream:
    def __init__(self, lib):
        self.lib, self.text = lib, ""

    def push(self, chunk):
        self.text += chunk
        return stated(snapshot(self.lib, self.text, False))

    def finish(self):
        return stated(snapshot(self.lib, self.text, True))


# ---------------------------------------------------------------------------
# §11.7 the canonical form

def is_name(s):
    return bool(s) and is_start(s[0]) and all(is_part(c) for c in s)


def jstr(s):
    out = ['"']
    for ch in s:
        o = ord(ch)
        if ch == '"':
            out.append('\\"')
        elif ch == "\\":
            out.append("\\\\")
        elif ch == "\b":
            out.append("\\b")
        elif ch == "\f":
            out.append("\\f")
        elif ch == "\n":
            out.append("\\n")
        elif ch == "\r":
            out.append("\\r")
        elif ch == "\t":
            out.append("\\t")
        elif o < 0x20:
            out.append("\\u%04x" % o)
        else:
            out.append(ch)
    out.append('"')
    return "".join(out)


def num_text(x):
    """The shortest decimal that reads back to x, positional, no exponent, no `.0`."""
    if x != x or x in (float("inf"), float("-inf")):
        raise ValueError("not finite")
    t = format(Decimal(repr(x)), "f")
    if "." in t:
        t = t.rstrip("0").rstrip(".")
    return t


RESERVED_IDS = {"Action"} | BUILTINS | STATE_ACTIONS


def val(v):
    t = v["type"]
    if t == "null":
        return "null"
    if t == "bool":
        return "true" if v["value"] else "false"
    if t == "number":
        return num_text(v["value"])
    if t == "text":
        return jstr(v["value"])
    if t == "list":
        return "[" + ", ".join(val(i) for i in v["value"]) + "]"
    if t == "object":
        parts = []
        for k in sorted(v["value"]):
            kk = k if is_name(k) and k not in ("true", "false", "null") else jstr(k)
            parts.append("%s: %s" % (kk, val(v["value"][k])))
        return "{" + ", ".join(parts) + "}"
    if t == "action":
        aid, payload = v["value"]["id"], v["value"]["payload"]
        if not is_name(aid) or aid in RESERVED_IDS:
            raise ValueError("action id")
        if payload is None:
            inner = ""
        elif payload["type"] == "list" and len(payload["value"]) >= 2:
            inner = ", ".join(val(i) for i in payload["value"])
        else:
            inner = val(payload)
        return "@%s(%s)" % (aid, inner)
    raise ValueError(t)


def write(tree, lib):
    reg = lib["widgets"]
    if validate(tree, reg):
        raise ValueError("invalid")
    flat = []

    def walk(w):
        flat.append(w)
        for c in w.get("children", []):
            walk(c)

    walk(tree)
    names, counts = [], {}
    for i, w in enumerate(flat):
        if i == 0:
            names.append("root")
            continue
        base = w["name"][0].lower() + w["name"][1:]
        counts[base] = counts.get(base, 0) + 1
        names.append("%s%d" % (base, counts[base]))
    out = []
    idx = [0]

    def size(w):
        return 1 + sum(size(c) for c in w.get("children", []))

    def emit(w):
        me = idx[0]
        idx[0] += 1
        if not ("A" <= w["name"][0] <= "Z") or w["name"] in ("Query", "Mutation", "Action") or not is_name(w["name"]):
            raise ValueError("not callable")
        s = reg[w["name"]]
        order = s["positional"]
        for p in w.get("props", {}):
            if p not in order:
                raise ValueError("not positional")
        child_names, at = [], me + 1
        for c in w.get("children", []):
            child_names.append(names[at])
            at += size(c)
        args = []
        for slot in order:
            if slot == "children":
                args.append("[" + ", ".join(child_names) + "]" if child_names else None)
                continue
            pv = w.get("props", {}).get(slot)
            if pv is None:
                args.append(None)
            elif pv["type"] == "null":
                raise ValueError("null prop")
            else:
                args.append(val(pv))
        while args and args[-1] is None:
            args.pop()
        out.append("%s = %s(%s)\n" % (names[me], w["name"], ", ".join("null" if a is None else a for a in args)))
        for c in w.get("children", []):
            emit(c)

    emit(tree)
    return "".join(out)


# ---------------------------------------------------------------------------
# the pack

def load(d):
    files = {}
    for n in sorted(os.listdir(d)):
        with open(os.path.join(d, n), "rb") as f:
            files[n] = f.read()
    return files


def norm_tree(t):
    """A tree for comparison: JSON numbers as floats."""
    return json.loads(json.dumps(t)) if t is not None else None


def check(files):
    """Every disagreement, as a list of lines; empty when the pack agrees."""
    bad = []
    man = json.loads(files["MANIFEST.json"])
    for n, digest in man["files"].items():
        if n not in files:
            bad.append("MANIFEST names %s, which the pack lacks" % n)
        elif "sha256:" + hashlib.sha256(files[n]).hexdigest() != digest:
            bad.append("%s: its SHA-256 is not the manifest's" % n)
    for n in files:
        if n != "MANIFEST.json" and n not in man["files"]:
            bad.append("%s is not in the manifest" % n)
    if bad:
        # A file the manifest does not name as it is: nothing in it is relied on.
        return bad
    lib = json.loads(files["library.json"])

    def same(a, b):
        return json.loads(json.dumps(a, sort_keys=True)) == json.loads(json.dumps(b, sort_keys=True))

    for c in json.loads(files["l1-statements.json"])["cases"]:
        s = snapshot(lib, c["input"], True)
        if not same(s["statements"], c["statements"]) or s["incomplete"] != c["incomplete"]:
            bad.append("L1 %s: got %s" % (c["name"], json.dumps(s["statements"])))
    l2 = {}
    for c in json.loads(files["l2-ingest.json"])["cases"]:
        s = stated(snapshot(lib, c["input"], True))
        l2[c["name"]] = s
        if not same(s, c["expected"]):
            bad.append("L2 %s: got %s" % (c["name"], json.dumps(s)[:600]))
    for c in json.loads(files["l3-stream.json"])["cases"]:
        st = Stream(lib)
        for i, ch in enumerate(c["chunks"]):
            s = st.push(ch)
            if not same(s, c["after_each"][i]):
                bad.append("L3 %s after chunk %d: got %s" % (c["name"], i, json.dumps(s)[:600]))
        end = st.finish()
        if not same(end, c["at_end"]):
            bad.append("L3 %s at the end: got %s" % (c["name"], json.dumps(end)[:600]))
        if not same(end, stated(snapshot(lib, "".join(c["chunks"]), True))):
            bad.append("L3 %s: the end of the stream is not the batch parse" % c["name"])
    for c in json.loads(files["l4-write.json"])["cases"]:
        try:
            text = write(c["tree"], lib)
        except ValueError as e:
            bad.append("L4 %s: not writable (%s)" % (c["name"], e))
            continue
        if text != c["text"]:
            bad.append("L4 %s: wrote %r" % (c["name"], text))
        back = snapshot(lib, c["text"], True)
        if not same(back["tree"], c["tree"]) or back["errors"]:
            bad.append("L4 %s: the text does not parse back to the tree" % c["name"])
    for c in json.loads(files["l5-refusals.json"])["cases"]:
        s = stated(snapshot(lib, c["input"], True))
        if not any(e["code"] == c["code"] and e["line"] == c["line"] for e in s["errors"]):
            bad.append("L5 %s: not refused %s at line %d" % (c["name"], c["code"], c["line"]))
        if not same(s, c["expected"]):
            bad.append("L5 %s: got %s" % (c["name"], json.dumps(s)[:600]))
    return bad


def mutations(files):
    """Changed vectors, each of which the verifier must refuse."""
    def edit(name, f):
        doc = json.loads(files[name])
        f(doc)
        out = dict(files)
        out[name] = (json.dumps(doc, indent=2, sort_keys=True) + "\n").encode()
        # keep the manifest true, so that the content check is what refuses it
        man = json.loads(out["MANIFEST.json"])
        man["files"][name] = "sha256:" + hashlib.sha256(out[name]).hexdigest()
        out["MANIFEST.json"] = (json.dumps(man, indent=2, sort_keys=True) + "\n").encode()
        return out

    def case(doc, n):
        return next(c for c in doc["cases"] if c["name"] == n)

    def first_text(t):
        if t and "props" in t:
            for k, v in t["props"].items():
                if v.get("type") == "text":
                    return t["props"], k
        for c in (t or {}).get("children", []):
            r = first_text(c)
            if r:
                return r
        return None

    def change_text(doc, n, key="expected"):
        props, k = first_text(case(doc, n)[key]["tree"])
        props[k]["value"] += "!"

    flipped = bytearray(files["l2-ingest.json"])
    flipped[100] ^= 0x01
    yield "a flipped byte under the manifest", dict(files, **{"l2-ingest.json": bytes(flipped)})
    yield "L1: a statement's line moved", edit("l1-statements.json", lambda d: d["cases"][0]["statements"][1].__setitem__("line", 9))
    yield "L1: complete flipped", edit("l1-statements.json", lambda d: d["cases"][0]["statements"][0].__setitem__("complete", False))
    yield "L2: a text changed", edit("l2-ingest.json", lambda d: change_text(d, "hoisting"))
    yield "L2: an unresolved name dropped", edit("l2-ingest.json", lambda d: case(d, "unresolved-left-out")["expected"]["unresolved"].clear())
    yield "L2: an orphan dropped", edit("l2-ingest.json", lambda d: case(d, "orphans")["expected"]["orphans"].clear())
    yield "L2: a key renamed", edit("l2-ingest.json", lambda d: case(d, "used-twice")["expected"]["nodes"][2].__setitem__("key", "t"))
    yield "L3: a pending title already whole", edit("l3-stream.json", lambda d: change_text(d, "pending-title-grows", "at_end"))
    yield "L3: an error not withheld", edit("l3-stream.json", lambda d: case(d, "errors-wait-for-completion")["after_each"][0]["errors"].append({"line": 3, "statement": "b", "code": "type-mismatch", "component": "Text", "prop": "text"}))
    yield "L4: the canonical text changed", edit("l4-write.json", lambda d: d["cases"][0].__setitem__("text", d["cases"][0]["text"].replace("card1", "c1", 1)))
    yield "L5: a refusal's line moved", edit("l5-refusals.json", lambda d: case(d, "unknown-component").__setitem__("line", 2))
    yield "L5: a refused widget kept", edit("l5-refusals.json", lambda d: case(d, "unknown-component")["expected"]["tree"]["children"].append({"name": "Chartt", "props": {}}))
    yield "L5: a code changed", edit("l5-refusals.json", lambda d: case(d, "disallowed-child")["expected"]["errors"][0].__setitem__("code", "type-mismatch"))


def main(argv):
    mut = "--mutations" in argv
    args = [a for a in argv if a != "--mutations"]
    d = args[0] if args else DEFAULT_PACK
    files = load(d)
    if mut:
        missed = 0
        n = 0
        for what, changed in mutations(files):
            n += 1
            if check(changed):
                print("refused: %s" % what)
            else:
                print("NOT REFUSED: %s" % what)
                missed += 1
        if check(files):
            print("the unchanged pack does not verify")
            return 1
        print("%d mutation(s), %d not refused" % (n, missed))
        return 1 if missed else 0
    bad = check(files)
    for b in bad:
        print(b)
    counts = {n: len(json.loads(files[n])["cases"]) for n in files if n[:1] == "l" and n[1:2].isdigit()}
    print("joule-ui-lang/v1: %s; %d disagreement(s)" % (", ".join("%s %d" % (k.split(".")[0], v) for k, v in sorted(counts.items())), len(bad)))
    return 1 if bad else 0


if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))