"""Emoji for the community forum only (the rest of the site stays emoji-free).

Unicode emoji in posts, titles and excerpts are drawn with the self-hosted
Twemoji set in static/emoji/ (CC-BY 4.0, see static/emoji/NOTICE.txt), so
every visitor sees the same artwork and no third-party host is contacted.
Discord-style shortcodes such as :rocket: work too, plus MoonBite's own
:moonbite:. Everything here runs on text that is already HTML-escaped, and
only ever inserts <img> tags whose src is built from a file that exists.
"""

from __future__ import annotations

import os
import re

_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "static", "emoji")
_URL = "/static/emoji/"

try:
    _NAMES = frozenset(f[:-4] for f in os.listdir(_DIR) if f.endswith(".svg"))
except OSError:  # emoji folder missing: fall back to the OS's own emoji font
    _NAMES = frozenset()
_MAXLEN = max((n.count("-") + 1 for n in _NAMES), default=1)

# MoonBite's own emoji (not Twemoji). shortcode -> file under static/emoji/custom/
CUSTOM = {"moonbite": "custom/moonbite.svg"}

# The picker's set, grouped like Discord's. (shortcode, emoji). Any other
# emoji still renders when typed or pasted; this is just what the picker offers.
PICKER = [
    ("People", [
        ("grinning", "😀"), ("smile", "😄"), ("joy", "😂"), ("rofl", "🤣"), ("wink", "😉"),
        ("blush", "😊"), ("heart_eyes", "😍"), ("star_struck", "🤩"), ("sunglasses", "😎"),
        ("thinking", "🤔"), ("raised_eyebrow", "🤨"), ("neutral_face", "😐"), ("rolling_eyes", "🙄"),
        ("smirk", "😏"), ("relieved", "😌"), ("sleeping", "😴"), ("exploding_head", "🤯"),
        ("partying_face", "🥳"), ("nerd", "🤓"), ("confused", "😕"), ("worried", "😟"),
        ("cry", "😢"), ("sob", "😭"), ("scream", "😱"), ("angry", "😠"), ("skull", "💀"),
        ("clown", "🤡"), ("ghost", "👻"), ("alien", "👽"), ("robot", "🤖"), ("eyes", "👀"),
        ("salute", "🫡"), ("melting_face", "🫠"), ("shushing_face", "🤫"), ("money_mouth", "🤑"),
    ]),
    ("Gestures", [
        ("thumbsup", "👍"), ("thumbsdown", "👎"), ("ok_hand", "👌"), ("clap", "👏"), ("wave", "👋"),
        ("raised_hands", "🙌"), ("pray", "🙏"), ("handshake", "🤝"), ("muscle", "💪"), ("fist", "👊"),
        ("v", "✌️"), ("crossed_fingers", "🤞"), ("point_up", "☝️"), ("point_right", "👉"),
        ("point_down", "👇"), ("call_me", "🤙"), ("writing_hand", "✍️"), ("brain", "🧠"),
    ]),
    ("Hearts", [
        ("heart", "❤️"), ("orange_heart", "🧡"), ("yellow_heart", "💛"), ("green_heart", "💚"),
        ("blue_heart", "💙"), ("purple_heart", "💜"), ("black_heart", "🖤"), ("white_heart", "🤍"),
        ("broken_heart", "💔"), ("sparkling_heart", "💖"), ("heart_on_fire", "❤️‍🔥"), ("100", "💯"),
    ]),
    ("Space", [
        ("rocket", "🚀"), ("moon", "🌙"), ("full_moon", "🌕"), ("new_moon", "🌑"), ("crescent_moon", "🌙"),
        ("first_quarter_moon", "🌓"), ("waxing_crescent_moon", "🌒"), ("earth", "🌍"), ("star", "⭐"),
        ("star2", "🌟"), ("sparkles", "✨"), ("comet", "☄️"), ("milky_way", "🌌"), ("sunny", "☀️"),
        ("zap", "⚡"), ("fire", "🔥"), ("rainbow", "🌈"), ("telescope", "🔭"), ("satellite", "🛰️"),
        ("flying_saucer", "🛸"), ("astronaut", "🧑‍🚀"),
    ]),
    ("Mining & tech", [
        ("pick", "⛏️"), ("hammer_and_pick", "⚒️"), ("hammer", "🔨"), ("wrench", "🔧"), ("gear", "⚙️"),
        ("computer", "💻"), ("desktop", "🖥️"), ("keyboard", "⌨️"), ("battery", "🔋"), ("electric_plug", "🔌"),
        ("bulb", "💡"), ("chart_up", "📈"), ("chart_down", "📉"), ("bar_chart", "📊"), ("coin", "🪙"),
        ("moneybag", "💰"), ("gem", "💎"), ("key", "🔑"), ("lock", "🔒"), ("unlock", "🔓"),
        ("shield", "🛡️"), ("link", "🔗"), ("chains", "⛓️"), ("package", "📦"), ("hourglass", "⏳"),
        ("stopwatch", "⏱️"), ("bell", "🔔"), ("mag", "🔍"), ("bug", "🐛"), ("test_tube", "🧪"),
        ("satellite_antenna", "📡"), ("globe", "🌐"),
    ]),
    ("Nature & food", [
        ("whale", "🐋"), ("shark", "🦈"), ("dog", "🐶"), ("cat", "🐱"), ("fox", "🦊"), ("owl", "🦉"),
        ("bear", "🐻"), ("bull", "🐂"), ("frog", "🐸"), ("unicorn", "🦄"), ("seedling", "🌱"),
        ("evergreen_tree", "🌲"), ("cactus", "🌵"), ("mushroom", "🍄"), ("pizza", "🍕"), ("cookie", "🍪"),
        ("doughnut", "🍩"), ("coffee", "☕"), ("beer", "🍺"), ("cheese", "🧀"), ("popcorn", "🍿"),
    ]),
    ("Symbols", [
        ("white_check_mark", "✅"), ("x", "❌"), ("warning", "⚠️"), ("no_entry", "⛔"), ("question", "❓"),
        ("exclamation", "❗"), ("tada", "🎉"), ("confetti_ball", "🎊"), ("trophy", "🏆"), ("medal", "🏅"),
        ("crown", "👑"), ("dart", "🎯"), ("game_die", "🎲"), ("pushpin", "📌"), ("memo", "📝"),
        ("books", "📚"), ("speech_balloon", "💬"), ("loudspeaker", "📢"), ("arrow_up", "⬆️"),
        ("arrow_down", "⬇️"), ("arrows_counterclockwise", "🔄"), ("new", "🆕"), ("free", "🆓"), ("sos", "🆘"),
    ]),
]

# Shortcode -> emoji, from the picker plus common aliases people type.
SHORTCODES = {name: ch for _, items in PICKER for name, ch in items}
SHORTCODES.update({
    "+1": "👍", "-1": "👎", "like": "👍", "joy_cat": "😹", "laughing": "😆", "lol": "😂",
    "pickaxe": "⛏️", "ok": "👌", "check": "✅", "money": "💰", "diamond": "💎", "gm": "🌅",
    "wagmi": "🚀", "lightning": "⚡", "flame": "🔥", "party": "🎉", "hundred": "💯",
})

_SHORT_RE = re.compile(r":([a-z0-9_+\-]{1,32}):")
_FE0F, _ZWJ = "️", "‍"


def key(seq: str) -> str:
    """Twemoji filename for an emoji sequence: hex codepoints joined by '-',
    with U+FE0F dropped unless the sequence has a zero-width joiner."""
    if _ZWJ not in seq:
        seq = seq.replace(_FE0F, "")
    return "-".join(f"{ord(c):x}" for c in seq)


def _img(src: str, alt: str, title: str = "") -> str:
    t = f' title=":{title}:"' if title else ""
    return (f'<img class="fx-emoji" src="{_URL}{src}" alt="{alt}"{t} '
            f'draggable="false" decoding="async">')


def _candidate(text: str, i: int) -> bool:
    o = ord(text[i])
    # Below U+2190 only keycaps and text symbols explicitly asking for emoji
    # presentation (FE0F), so plain digits, '#', (c) and (r) stay text.
    return o >= 0x2190 or (i + 1 < len(text) and text[i + 1] in (_FE0F, "⃣"))


def _scan(text: str):
    """Yield (is_emoji, piece) runs over `text`, longest match first."""
    i, n, start = 0, len(text), 0
    while i < n:
        if _candidate(text, i):
            for length in range(min(_MAXLEN + 2, n - i), 0, -1):
                seq = text[i:i + length]
                if key(seq) in _NAMES:
                    if start < i:
                        yield False, text[start:i]
                    yield True, seq
                    i += length
                    start = i
                    break
            else:
                i += 1
        else:
            i += 1
    if start < n:
        yield False, text[start:]


def _shortcodes(escaped: str) -> str:
    def sub(m):
        name = m.group(1)
        if name in CUSTOM:
            return _img(CUSTOM[name], f":{name}:", name)
        ch = SHORTCODES.get(name)
        if ch and key(ch) in _NAMES:
            return _img(key(ch) + ".svg", ch, name)
        return m.group(0)
    return _SHORT_RE.sub(sub, escaped)


def emojify(escaped: str) -> str:
    """Replace emoji and known :shortcodes: in already-escaped text with
    Twemoji images. Text that isn't an emoji passes through untouched."""
    if not _NAMES:
        return escaped
    out = []
    for is_emoji, piece in _scan(escaped):
        if is_emoji:
            out.append(_img(key(piece) + ".svg", piece))
        else:
            out.append(_shortcodes(piece))
    return "".join(out)


def emoji_only(text: str, limit: int = 8) -> bool:
    """True when `text` is nothing but 1..limit emoji (Discord-style jumbo)."""
    text = _SHORT_RE.sub(lambda m: "\x00" if (m.group(1) in CUSTOM or m.group(1) in SHORTCODES) else m.group(0), text.strip())
    count = text.count("\x00")
    rest = []
    for is_emoji, piece in _scan(text.replace("\x00", "")):
        if is_emoji:
            count += 1
        else:
            rest.append(piece)
    return 0 < count <= limit and "".join(rest).strip() == ""


def picker_data() -> list:
    """Picker groups for the composer: [{"name", "items": [{s, c, k}]}]."""
    groups = [{"name": "MoonBite", "items": [{"s": n, "c": f":{n}:", "k": f} for n, f in CUSTOM.items()]}]
    for name, items in PICKER:
        groups.append({"name": name, "items": [
            {"s": s, "c": ch, "k": key(ch) + ".svg"} for s, ch in items if key(ch) in _NAMES
        ]})
    return groups