"""Ren'Py screen language → PGVN screen IR.

Only the part games use for their own interface is translated (HUDs, hotspot menus,
phones, inventories). Whatever is not understood is reported through ``warn`` so a game
never imports with a half-working screen.

A screen is ``{"params": [...], "props": {...}, "defaults": [[name, expr]], "body": [node]}``.
Nodes:

* widget ``{"w": kind, "args": [expr], "props": {name: expr}, "body": [node]}``
* ``{"c": "if", "branches": [{"c": expr | None, "body": [...]}]}``
* ``{"c": "for", "t": target, "it": expr, "body": [...]}``
* ``{"c": "use", "name": str, "args": [expr], "kw": {}, "body": [...]}`` (body = transcluded children)
* ``{"c": "transclude"}``, ``{"c": "python", "code": [stmt]}``
* ``{"c": "key", "key": expr, "action": expr}``, ``{"c": "timer", ...}``, ``{"c": "on", "event": str, ...}``
"""
import ast
import re
from collections.abc import Callable
from typing import Any

from app.converter import pyexpr
from app.converter.atl import WARPER
from app.converter.exprtokens import read_value
from app.converter.pyexpr import Unsupported
from app.converter.rpy_lexer import Line

Node = dict[str, Any]

# Calls whose first argument names a screen to open
OPENERS = {"Show", "ShowTransient", "ToggleScreen", "Hide", "show_screen", "call_screen", "hide_screen"}

CONTAINERS = {"fixed", "frame", "window", "vbox", "hbox", "grid", "vpgrid", "viewport", "button"}
LEAVES = {"text", "label", "textbutton", "imagebutton", "add", "image", "null", "bar", "vbar"}
POSITIONAL = {"text": 1, "label": 1, "textbutton": 1, "add": 1, "image": 1, "grid": 2}
ATL_WORDS = {"pause", "repeat", "parallel", "choice", "block", "contains", "function", "time"}

LAYOUT = set("""xpos ypos pos xanchor yanchor anchor xalign yalign align xcenter ycenter xoffset yoffset
xsize ysize xysize xminimum yminimum xmaximum ymaximum minimum maximum xfill yfill area spacing xspacing
yspacing padding xpadding ypadding left_padding right_padding top_padding bottom_padding margin xmargin
ymargin left_margin right_margin top_margin bottom_margin width height""".split())
LOOK = set("""background foreground idle hover insensitive selected selected_idle selected_hover
selected_insensitive auto ground left_bar right_bar top_bar bottom_bar thumb alpha zoom rotate xzoom yzoom
clipping fit_first xfit yfit box_reverse box_wrap order_reverse transpose rows cols crop size_group
xtile ytile matrixcolor blur""".split())
TEXT = set("""color size font bold italic underline strikethrough outlines text_align textalign line_spacing
kerning layout first_indent min_width antialias xalign yalign justify hyperlink_functions slow_cps""".split())
BEHAVIOUR = set("""action alternate hovered unhovered sensitive tooltip focus_mask mouse hover_sound
activate_sound focus keysym alt id modal zorder tag layer variant style style_prefix at value range
adjustment changed mousewheel draggable scrollbars xinitial yinitial child_size edgescroll arrowkeys
text_style properties substitute prefix suffix repeat""".split())
# Scrolling widgets share state through adjustments; scrollbars are cosmetic in the browser
IGNORED_PREFIXES = ("scrollbar_", "vscrollbar_", "bar_", "side_", "thumb_", "slider_", "vslider_", "left_gutter",
                    "right_gutter", "top_gutter", "bottom_gutter")
IGNORED = {"xadjustment", "yadjustment", "pagekeys", "unscrollable", "arrowkeys", "edgescroll", "draggable",
           "child_size", "focus", "mouse", "alt", "properties", "substitute", "prefix", "suffix", "keysym"}
STATE_PREFIXES = ("idle", "hover", "insensitive", "selected", "selected_idle", "selected_hover",
                  "selected_insensitive")
ALL = LAYOUT | LOOK | TEXT | BEHAVIOUR
SCREEN_PROPS = {"zorder", "modal", "tag", "variant", "style_prefix", "layer", "sensitive", "style"}
DESKTOP_VARIANTS = {"pc", "large", "web", "medium", "small"}
GLUED = re.compile(r"^([a-z_][a-z_0-9]*)(\(.*\)|\[.*\])$", re.S)


def known_property(name: str) -> bool:
    if name in ALL or name in IGNORED or name.startswith(IGNORED_PREFIXES):
        return True
    if name.startswith("text_") and name[5:] in TEXT | LAYOUT:
        return True
    for prefix in STATE_PREFIXES:
        if name.startswith(prefix + "_") and known_property(name[len(prefix) + 1:]):
            return True
    return False


def ignorable(name: str) -> bool:
    return name in IGNORED or name.startswith(IGNORED_PREFIXES)


def tokens(text: str) -> list[str]:
    """Split on whitespace outside brackets and quotes (Ren'Py "simple expressions")."""
    out, cur, depth, quote, escaped = [], [], 0, "", False
    for ch in text:
        if quote:
            cur.append(ch)
            if escaped:
                escaped = False
            elif ch == "\\":
                escaped = True
            elif ch == quote:
                quote = ""
        elif ch in "\"'":
            quote = ch
            cur.append(ch)
        elif ch in "([{":
            depth += 1
            cur.append(ch)
        elif ch in ")]}":
            depth -= 1
            cur.append(ch)
        elif ch.isspace() and depth == 0:
            if cur:
                out.append("".join(cur))
                cur = []
        else:
            cur.append(ch)
    if cur:
        out.append("".join(cur))
    return out


class ScreenParser:
    def __init__(self, warn: Callable[[str, Line], None], transform_ref: Callable[[str, Line], dict],
                 atl: Callable[[list[Line]], tuple[dict, dict | None]] | None = None):
        self.warn = warn
        self.transform_ref = transform_ref
        self.atl = atl
        self.defaults: list[list[Any]] = []

    def expr(self, source: str, line: Line) -> dict | None:
        try:
            return pyexpr.parse_expr(source)
        except Unsupported as exc:
            self.warn(f"Выражение в screen: {exc}", line)
            return None

    # --- definition -----------------------------------------------------------------

    def screen(self, line: Line) -> tuple[str, dict] | None:
        header = line.text.strip().rstrip(":").strip()
        match = re.fullmatch(r"screen\s+([A-Za-z_]\w*)\s*(\((.*)\))?", header, re.S)
        if not match:
            self.warn("Не разобран заголовок screen", line)
            return None
        name = match.group(1)
        try:
            params = pyexpr.params(ast.parse(f"def f({match.group(3) or ''}): pass").body[0].args)
        except (SyntaxError, Unsupported):
            self.warn(f"Не разобраны параметры screen {name}", line)
            return None
        self.defaults = []
        props, body = self.body(line.block, top=True)
        props.pop("__atl__", None)
        props.pop("__if__", None)
        if "variant" in props:
            variants = props["variant"]
            text = variants["v"] if variants.get("k") == "const" else ""
            if not any(v in DESKTOP_VARIANTS for v in re.findall(r"[a-z]+", str(text))):
                return None  # touch/phone layouts never apply to the desktop browser player
            props.pop("variant")
        return name, {"params": params, "props": props, "defaults": self.defaults, "body": body}

    # --- statements -----------------------------------------------------------------

    def is_atl(self, words: list[str]) -> bool:
        first = words[0]
        if first == "on":
            return len(words) > 1 and not words[1].startswith(("'", '"'))
        return first in ATL_WORDS or bool(WARPER.match(first))

    def body(self, lines: list[Line], top: bool = False) -> tuple[dict[str, Any], list[Node]]:
        """Returns (properties declared in the block, child nodes)."""
        props: dict[str, Any] = {}
        nodes: list[Node] = []
        atl_lines: list[Line] = []
        conditional: list[list[dict]] = []
        i = 0
        while i < len(lines):
            line = lines[i]
            text = line.text.rstrip(":").strip() if line.block else line.text.strip()
            words = tokens(re.sub(r"^(if|elif|showif)\(", r"\1 (", text))
            i += 1
            if not words:
                continue
            first = words[0]
            if first in ("if", "showif"):
                branches = [self.branch(first, words, line)]
                while i < len(lines):
                    nxt = tokens(re.sub(r"^(elif|else)\(", r"\1 (", lines[i].text.rstrip(":").strip()))
                    if not nxt or nxt[0] not in ("elif", "else"):
                        break
                    branches.append(self.branch(nxt[0], nxt, lines[i]))
                    i += 1
                branches = [b for b in branches if b]
                if not top and branches and not any(b["body"] for b in branches) and any(b["props"] for b in branches):
                    # `if` inside a widget that only sets properties (idle "a" / idle "b")
                    conditional.append([{"c": b["c"], "props": b["props"]} for b in branches])
                else:
                    nodes.append({"c": "if", "branches": [{"c": b["c"], "body": b["body"]} for b in branches]})
            elif first in ("elif", "else"):
                self.warn(f"Не поддерживается в screen: {first} без if", line)
            elif first == "for":
                node = self.for_loop(line)
                if node:
                    nodes.append(node)
            elif first == "use":
                node = self.use(line, words)
                if node:
                    nodes.append(node)
            elif first == "transclude":
                nodes.append({"c": "transclude"})
            elif first == "has":
                # `has vbox`: the rest of this block goes inside a new container
                container = self.widget(line, words[1:])
                if container:
                    _, rest = self.body(lines[i:])
                    container["body"].extend(rest)
                    nodes.append(container)
                i = len(lines)
            elif first == "python" and line.text.strip() == "python:" or first == "$":
                nodes.extend(self.python(line, first))
            elif first == "default":
                self.default(line)
            elif first == "key":
                node = self.key(line, words)
                if node:
                    nodes.append(node)
            elif first == "timer":
                node = self.timer(line, words)
                if node:
                    nodes.append(node)
            elif first == "on" and not self.is_atl(words):
                node = self.on(line, words)
                if node:
                    nodes.append(node)
            elif self.is_atl(words) and not top:
                atl_lines.append(line)
            elif first in CONTAINERS or first in LEAVES:
                node = self.widget(line, words)
                if node:
                    nodes.append(node)
            elif (top and first in SCREEN_PROPS) or known_property(GLUED.sub(r"\1", first)):
                props.update(self.properties(words, line))
            else:
                self.warn(f"Не поддерживается в screen: {first}", line)
        if atl_lines:
            props["__atl__"] = atl_lines
        if conditional:
            props["__if__"] = conditional
        return props, nodes

    def branch(self, kind: str, words: list[str], line: Line) -> dict | None:
        cond = None
        if kind != "else":
            cond = self.expr(" ".join(words[1:]), line)
            if cond is None:
                return None
        props, body = self.body(line.block)
        props.pop("__atl__", None)
        return {"c": cond, "body": body, "props": props}

    def for_loop(self, line: Line) -> Node | None:
        try:
            stmt = pyexpr.parse_stmts(line.text.strip().rstrip(":") + ":\n    pass")[0]
        except Unsupported as exc:
            self.warn(f"Цикл в screen: {exc}", line)
            return None
        _, body = self.body(line.block)
        return {"c": "for", "t": stmt["t"], "it": stmt["it"], "body": body}

    def use(self, line: Line, words: list[str]) -> Node | None:
        call = self.expr(" ".join(words[1:]), line)
        if call is None:
            return None
        if call["k"] == "name":
            node = {"c": "use", "name": call["id"], "args": [], "kw": {}}
        elif call["k"] == "call" and call["f"]["k"] == "name":
            node = {"c": "use", "name": call["f"]["id"], "args": call["a"], "kw": call["kw"]}
        else:
            self.warn("Не разобран use в screen", line)
            return None
        if line.block:  # children are placed where the used screen says `transclude`
            _, node["body"] = self.body(line.block)
        return node

    def python(self, line: Line, first: str) -> list[Node]:
        source = line.text.strip()[1:].strip() if first == "$" else line.block_source()
        try:
            return [{"c": "python", "code": pyexpr.parse_stmts(source)}]
        except Unsupported as exc:
            self.warn(f"Python в screen: {exc}", line)
            return []

    def default(self, line: Line) -> None:
        match = re.fullmatch(r"default\s+([A-Za-z_]\w*)\s*=\s*(.+)", line.text.strip(), re.S)
        value = self.expr(match.group(2), line) if match else None
        if not match or value is None:
            self.warn("Не разобран default в screen", line)
            return
        self.defaults.append([match.group(1), value])

    def block_properties(self, words: list[str], line: Line) -> dict[str, Any]:
        props = self.properties(words, line)
        for child in line.block:
            props.update(self.properties(tokens(child.text), child))
        return props

    def key(self, line: Line, words: list[str]) -> Node | None:
        shortcut = self.expr(words[1], line) if len(words) > 1 else None
        props = self.block_properties(words[2:], line)
        if shortcut is None or "action" not in props:
            self.warn("Не разобран key в screen", line)
            return None
        return {"c": "key", "key": shortcut, "action": props["action"]}

    def timer(self, line: Line, words: list[str]) -> Node | None:
        delay = self.expr(words[1], line) if len(words) > 1 else None
        props = self.block_properties(words[2:], line)
        if delay is None or "action" not in props:
            self.warn("Не разобран timer в screen", line)
            return None
        return {"c": "timer", "delay": delay, "action": props["action"], "repeat": props.get("repeat")}

    def on(self, line: Line, words: list[str]) -> Node | None:
        event = self.expr(words[1], line) if len(words) > 1 else None
        props = self.block_properties(words[2:], line)
        if event is None or event.get("k") != "const" or "action" not in props:
            self.warn("Не разобран on в screen", line)
            return None
        if event["v"] not in ("show", "hide", "replace", "replaced"):
            self.warn(f"Не поддерживается в screen: событие {event['v']}", line)
            return None
        return {"c": "on", "event": event["v"], "action": props["action"]}

    # --- widgets --------------------------------------------------------------------

    def widget(self, line: Line, words: list[str]) -> Node | None:
        kind = words[0]
        if kind == "image":
            kind = "add"
        if kind not in CONTAINERS and kind not in LEAVES:
            self.warn(f"Не поддерживается в screen: {kind}", line)
            return None
        args = []
        i = 1
        for _ in range(POSITIONAL.get(kind, 0)):
            if i >= len(words):
                break
            source, i = read_value(words, i)
            value = self.expr(source, line)
            if value is None:
                return None
            args.append(value)
        if len(args) < POSITIONAL.get(kind, 0) and kind not in ("text", "label"):
            self.warn(f"У {kind} в screen не хватает аргументов", line)
            return None
        props = self.properties(words[i:], line)
        body: list[Node] = []
        if line.block:
            more, body = self.body(line.block)
            props.update(more)
        atl_lines = props.pop("__atl__", None)
        conditional = props.pop("__if__", None)
        if atl_lines:
            self.inline_atl(props, atl_lines, line)
        if body and kind in LEAVES:
            self.warn(f"{kind} в screen не может содержать вложенные элементы", line)
            return None
        if kind in ("bar", "vbar"):
            props["vertical"] = {"k": "const", "v": kind == "vbar"}
        node: Node = {"w": kind, "args": args, "props": props, "body": body}
        if conditional:
            node["propIf"] = conditional
        return node

    def inline_atl(self, props: dict[str, Any], lines: list[Line], line: Line) -> None:
        if self.atl is None:
            self.warn("Не поддерживается в screen: ATL в виджете", line)
            return
        static, animation = self.atl(lines)
        spec: dict[str, Any] = {"props": static}
        if animation:
            spec["atl"] = animation
        props["at"] = [*props.get("at", []), spec]

    def properties(self, words: list[str], line: Line, lenient: bool = False) -> dict[str, Any]:
        props: dict[str, Any] = {}
        i = 0
        while i < len(words):
            key, glued = words[i], None
            match = GLUED.match(key)
            if match and (known_property(match[1]) or match[1] in SCREEN_PROPS):
                key, glued = match[1], match[2]
            if known_property(key) or key in SCREEN_PROPS:
                pass
            elif key in ("with", "nopredict"):
                i += 1
                continue
            elif lenient:  # styles carry many purely cosmetic properties we do not render
                i += 2
                continue
            else:
                self.warn(f"Не поддерживается в screen: свойство {key}", line)
                return props
            if glued is None and i + 1 >= len(words):
                self.warn(f"У свойства {key} нет значения", line)
                return props
            if key == "at" and glued is None:
                # `at a, b` / `at transform_name(args)`; transforms are not Python values
                items, i = [], i + 1
                while i < len(words):
                    items.append(words[i].rstrip(","))
                    more = words[i].endswith(",")
                    i += 1
                    if not more:
                        break
                props["at"] = [self.transform_ref(item, line) for item in items if item]
                continue
            if glued is not None:
                source, i = glued, i + 1
            else:
                source, i = read_value(words, i + 1)
            if ignorable(key):
                continue
            value = self.expr(source, line)
            if value is not None:
                props[key] = value
        return props


def referenced_screens(definition: Any, known: dict[str, Any]) -> set[str]:
    """Screens a screen may open: `use` targets and string constants naming a screen."""
    found: set[str] = set()

    def visit(value: Any) -> None:
        if isinstance(value, dict):
            if value.get("c") == "use" and value.get("name") in known:
                found.add(value["name"])
            if value.get("k") == "call" and value.get("a"):
                function, first = value["f"], value["a"][0]
                name = function.get("id") if function.get("k") == "name" else (
                    function.get("a") if function.get("k") == "attr" else "")
                if (name in OPENERS and first.get("k") == "const" and first.get("v") in known):
                    found.add(first["v"])
            for child in value.values():
                visit(child)
        elif isinstance(value, list):
            for child in value:
                visit(child)

    visit(definition)
    return found