"""Google Chat outbound text formatting and Cards v2 rendering.

Extracted from ``adapter.py``; the card dict shapes and key order here are the
wire format and must stay byte-identical.
"""

from __future__ import annotations

import re
from typing import Any, Callable, Dict, List

# Invisible Unicode codepoints that render as tofu (□) in Google Chat's
# restricted font stack: ZWS/ZWNJ/ZWJ, bidi marks, word joiner, BOM and
# Variation Selectors (Chat ignores them and often shows a blank box).
_INVISIBLE_RE = re.compile(
    "["
    "\u200b"          # Zero-Width Space
    "\u200c"          # Zero-Width Non-Joiner
    "\u200d"          # Zero-Width Joiner (ZWJ)
    "\u200e\u200f"    # LTR / RTL marks
    "\u2060"          # Word Joiner
    "\ufeff"          # BOM / Zero-Width No-Break Space
    "\ufe00-\ufe0f"   # Variation Selectors 1-16 (VS1–VS16)
    "\U000e0100-\U000e01ef"  # Variation Selectors 17-256
    "]"
)


def format_message(content: str) -> str:
    """Convert standard Markdown to Google Chat's dialect.

    Chat renders only ``*bold*``, ``_italic_``, ``~strike~`` and code; ``**bold**``,
    ``# headers`` and ``[text](url)`` must be converted. Fenced and inline code
    are protected via placeholders so literal asterisks/brackets inside them
    survive; invisible tofu codepoints are stripped at the end.
    """
    if not content:
        return content

    text = content
    placeholders: Dict[str, str] = {}
    counter = [0]

    def _ph(value: str) -> str:
        key = f"\x00GC{counter[0]}\x00"
        counter[0] += 1
        placeholders[key] = value
        return key

    # Protect fenced blocks first, then inline code.
    text = re.sub(r"(```(?:[^\n]*\n)?[\s\S]*?```)", lambda m: _ph(m.group(0)), text)
    text = re.sub(r"(`[^`]+`)", lambda m: _ph(m.group(0)), text)
    # Headers (## Title) → *Title* (Chat has no header support).
    text = re.sub(r"^#{1,6}\s+(.+)$", lambda m: _ph(f"*{m.group(1).strip()}*"), text, flags=re.MULTILINE)
    # ***text*** → *_text_*, then **text** → *text*.
    text = re.sub(r"\*\*\*(.+?)\*\*\*", lambda m: _ph(f"*_{m.group(1)}_*"), text)
    text = re.sub(r"\*\*(.+?)\*\*", lambda m: _ph(f"*{m.group(1)}*"), text)
    # [text](url) → <url|text> (Slack-style angle-bracket).
    text = re.sub(r"\[([^\]]+)\]\(([^)]+)\)", lambda m: _ph(f"<{m.group(2)}|{m.group(1)}>"), text)
    text = _INVISIBLE_RE.sub("", text)
    # Collapse double spaces left over from stripped chars.
    text = re.sub(r"  +", " ", text)
    for key, value in placeholders.items():
        text = text.replace(key, value)
    return text


def _required_str(mapping: Dict[str, Any], key: str, context: str) -> str:
    value = mapping.get(key)
    if value is None:
        raise ValueError(f"{context}.{key} is required")
    value = str(value).strip()
    if not value:
        raise ValueError(f"{context}.{key} is required")
    return value


def _button_to_chat(button: Dict[str, Any]) -> Dict[str, Any]:
    text = _required_str(button, "text", "button")
    action = _required_str(button, "action", "button")
    raw_params = button.get("parameters") or {}
    if not isinstance(raw_params, dict):
        raise ValueError("button.parameters must be an object")
    parameters = [{"key": str(key), "value": str(value)} for key, value in sorted(raw_params.items())]
    return {
        "text": text,
        "onClick": {"action": {"function": action, "parameters": parameters}},
    }


def _text_widget(widget: Dict[str, Any]) -> Dict[str, Any]:
    return {"textParagraph": {"text": format_message(_required_str(widget, "text", "widget"))}}


def _decorated_text_widget(widget: Dict[str, Any]) -> Dict[str, Any]:
    decorated: Dict[str, Any] = {
        "text": format_message(_required_str(widget, "text", "widget")),
        "wrapText": bool(widget.get("wrap_text", True)),
    }
    if widget.get("top_label"):
        decorated["topLabel"] = str(widget["top_label"])
    if widget.get("bottom_label"):
        decorated["bottomLabel"] = str(widget["bottom_label"])
    return {"decoratedText": decorated}


def _image_widget(widget: Dict[str, Any]) -> Dict[str, Any]:
    image = {"imageUrl": _required_str(widget, "image_url", "widget")}
    if widget.get("alt_text"):
        image["altText"] = str(widget["alt_text"])
    return {"image": image}


def _buttons_widget(widget: Dict[str, Any]) -> Dict[str, Any]:
    raw_buttons = widget.get("buttons") or []
    if not isinstance(raw_buttons, list) or not raw_buttons:
        raise ValueError("button widgets require at least one button")
    return {"buttonList": {"buttons": [_button_to_chat(btn) for btn in raw_buttons]}}


def _selection_widget(widget: Dict[str, Any]) -> Dict[str, Any]:
    name = _required_str(widget, "name", "widget")
    raw_items = widget.get("items") or []
    if not isinstance(raw_items, list) or not raw_items:
        raise ValueError("selection widgets require at least one item")
    items: List[Dict[str, Any]] = []
    for item in raw_items:
        if not isinstance(item, dict):
            raise ValueError("selection items must be objects")
        items.append({
            "text": _required_str(item, "text", "selection item"),
            "value": _required_str(item, "value", "selection item"),
            "selected": bool(item.get("selected", False)),
        })
    return {
        "selectionInput": {
            "name": name,
            "label": str(widget.get("label") or name),
            "type": str(widget.get("selection_type") or "CHECK_BOX"),
            "items": items,
        }
    }


_WIDGET_RENDERERS: Dict[str, Callable[[Dict[str, Any]], Dict[str, Any]]] = {
    "text": _text_widget,
    "text_paragraph": _text_widget,
    "decorated_text": _decorated_text_widget,
    "buttons": _buttons_widget,
    "button_list": _buttons_widget,
    "selection": _selection_widget,
    "selection_input": _selection_widget,
    "image": _image_widget,
    "divider": lambda widget: {"divider": {}},
}


def _widget_to_chat(widget: Dict[str, Any]) -> Dict[str, Any]:
    if not isinstance(widget, dict):
        raise ValueError("card widgets must be objects")
    widget_type = str(widget.get("type") or "").strip()
    renderer = _WIDGET_RENDERERS.get(widget_type)
    if renderer is None:
        raise ValueError(f"unsupported widget type: {widget_type or '<missing>'}")
    return renderer(widget)


def card_spec_to_cards_v2(card_spec: Dict[str, Any]) -> Dict[str, Any]:
    if not isinstance(card_spec, dict):
        raise ValueError("card must be an object")
    raw_sections = card_spec.get("sections") or []
    if not isinstance(raw_sections, list) or not raw_sections:
        raise ValueError("card.sections must contain at least one section")

    sections: List[Dict[str, Any]] = []
    for section in raw_sections:
        if not isinstance(section, dict):
            raise ValueError("card sections must be objects")
        widgets = section.get("widgets") or []
        if not isinstance(widgets, list) or not widgets:
            raise ValueError("card section widgets must contain at least one widget")
        rendered: Dict[str, Any] = {"widgets": [_widget_to_chat(w) for w in widgets]}
        if section.get("header"):
            rendered["header"] = str(section["header"])
        sections.append(rendered)

    card: Dict[str, Any] = {"sections": sections}
    header = card_spec.get("header")
    if header:
        if not isinstance(header, dict):
            raise ValueError("card.header must be an object")
        rendered_header: Dict[str, Any] = {"title": _required_str(header, "title", "card.header")}
        if header.get("subtitle"):
            rendered_header["subtitle"] = str(header["subtitle"])
        if header.get("image_url"):
            rendered_header["imageUrl"] = str(header["image_url"])
            rendered_header["imageType"] = str(header.get("image_type") or "SQUARE")
        if header.get("image_alt_text"):
            rendered_header["imageAltText"] = str(header["image_alt_text"])
        card["header"] = rendered_header
    return {"cardId": str(card_spec.get("card_id") or "hermes-card"), "card": card}