import hashlib
import random
from datetime import date
from html import escape
from urllib.parse import quote

import gradio as gr
import requests
import spaces


WIKIPEDIA_API = "https://en.wikipedia.org/w/api.php"

CHALLENGES = [
    ("Motorcycle", "Black hole"),
    ("Coffee", "Moon"),
    ("Rubber duck", "Artificial intelligence"),
    ("Pizza", "Quantum mechanics"),
    ("Harley-Davidson", "Computer science"),
    ("Volcano", "Internet"),
    ("Shark", "Electricity"),
    ("Chess", "Space exploration"),
    ("New York City", "Dinosaur"),
    ("Heavy metal music", "Ancient Egypt"),
    ("Video game", "Solar System"),
    ("Submarine", "World Wide Web"),
]


@spaces.GPU(duration=1)
def zerogpu_compatibility():
    """Allows this lightweight app to start on ZeroGPU hardware."""
    return True


def wikipedia_request(params: dict) -> dict:
    response = requests.get(
        WIKIPEDIA_API,
        params={
            **params,
            "format": "json",
            "formatversion": 2,
            "origin": "*",
        },
        timeout=20,
        headers={
            "User-Agent": "WikiQuest/1.0 (Hugging Face educational game)"
        },
    )
    response.raise_for_status()
    return response.json()


def normalize_title(title: str) -> str:
    return " ".join(title.strip().split())


def resolve_article(title: str) -> str:
    data = wikipedia_request(
        {
            "action": "query",
            "titles": title,
            "redirects": 1,
        }
    )

    pages = data.get("query", {}).get("pages", [])

    if not pages or pages[0].get("missing"):
        raise ValueError(f'Wikipedia could not find an article named "{title}".')

    return pages[0].get("title", title)


def get_article_data(title: str, link_limit: int = 120) -> tuple[str, str, list[str]]:
    data = wikipedia_request(
        {
            "action": "query",
            "prop": "extracts|links",
            "titles": title,
            "redirects": 1,
            "exintro": 1,
            "explaintext": 1,
            "plnamespace": 0,
            "pllimit": link_limit,
        }
    )

    pages = data.get("query", {}).get("pages", [])

    if not pages or pages[0].get("missing"):
        raise ValueError(f'Wikipedia could not load "{title}".')

    page = pages[0]
    resolved_title = page.get("title", title)
    summary = page.get("extract") or "No introductory summary was available."

    links = []
    blocked_prefixes = (
        "List of",
        "Outline of",
        "Index of",
        "Glossary of",
        "Timeline of",
    )

    for item in page.get("links", []):
        link_title = item.get("title", "").strip()

        if not link_title:
            continue

        if link_title.startswith(blocked_prefixes):
            continue

        if link_title.casefold() == resolved_title.casefold():
            continue

        links.append(link_title)

    return resolved_title, summary[:900], sorted(set(links))


def get_link_titles(title: str, limit: int = 100) -> set[str]:
    try:
        _, _, links = get_article_data(title, limit)
        return {item.casefold() for item in links}
    except Exception:
        return set()


def title_words(title: str) -> set[str]:
    ignored = {
        "a",
        "an",
        "and",
        "the",
        "of",
        "in",
        "on",
        "to",
        "for",
        "with",
        "by",
    }

    cleaned = "".join(
        character.lower() if character.isalnum() else " "
        for character in title
    )

    return {
        word
        for word in cleaned.split()
        if len(word) > 2 and word not in ignored
    }


def connection_score(
    article: str,
    target: str,
    article_links: set[str] | None = None,
) -> float:
    if article.casefold() == target.casefold():
        return 100.0

    article_words = title_words(article)
    target_words = title_words(target)

    word_overlap = len(article_words & target_words)
    score = word_overlap * 16.0

    article_lower = article.casefold()
    target_lower = target.casefold()

    if article_lower in target_lower or target_lower in article_lower:
        score += 25.0

    if article_links and target_lower in article_links:
        score += 55.0

    return min(score, 95.0)


def select_destinations(
    links: list[str],
    target: str,
    amount: int = 12,
) -> list[str]:
    if not links:
        return []

    target_lower = target.casefold()
    target_terms = title_words(target)

    def rank(link: str) -> tuple[int, int, int]:
        link_terms = title_words(link)
        exact_target = int(link.casefold() == target_lower)
        shared_terms = len(link_terms & target_terms)
        readable_length = -abs(len(link) - 18)

        return exact_target, shared_terms, readable_length

    ranked = sorted(links, key=rank, reverse=True)

    priority = ranked[:5]
    remaining = [link for link in links if link not in priority]

    seed_text = f"{target}|{'|'.join(links[:20])}"
    seed = int(hashlib.sha256(seed_text.encode()).hexdigest()[:12], 16)
    local_random = random.Random(seed)
    local_random.shuffle(remaining)

    selected = priority + remaining[: max(0, amount - len(priority))]

    if target in links and target not in selected:
        selected[-1] = target

    return selected[:amount]


def daily_challenge() -> tuple[str, str]:
    today_number = date.today().toordinal()
    return CHALLENGES[today_number % len(CHALLENGES)]


def random_challenge() -> tuple[str, str]:
    return random.choice(CHALLENGES)


def make_header(
    current: str,
    target: str,
    clicks: int,
    temperature: str,
) -> str:
    return f"""
    <div class="mission-grid">
        <div class="mission-card current-card">
            <span class="eyebrow">CURRENT LOCATION</span>
            <h2>{escape(current)}</h2>
        </div>

        <div class="mission-arrow">
            <span>➜</span>
        </div>

        <div class="mission-card target-card">
            <span class="eyebrow">TARGET DESTINATION</span>
            <h2>{escape(target)}</h2>
        </div>
    </div>

    <div class="game-stats">
        <div class="stat-pill">
            <span class="stat-label">MOVES</span>
            <strong>{clicks}</strong>
        </div>

        <div class="stat-pill heat-pill">
            <span class="stat-label">SIGNAL</span>
            <strong>{escape(temperature)}</strong>
        </div>
    </div>
    """


def make_article_card(title: str, summary: str) -> str:
    article_url = (
        "https://en.wikipedia.org/wiki/"
        + quote(title.replace(" ", "_"), safe="")
    )

    return f"""
    <section class="article-panel">
        <div class="article-heading">
            <span class="location-pin">◉</span>
            <div>
                <span class="eyebrow">YOU HAVE ARRIVED AT</span>
                <h1>{escape(title)}</h1>
            </div>
        </div>

        <p>{escape(summary)}</p>

        <a
            class="wiki-link"
            href="{article_url}"
            target="_blank"
            rel="noopener noreferrer"
        >
            Read the full Wikipedia article ↗
        </a>
    </section>
    """


def make_path(path: list[str]) -> str:
    if not path:
        return """
        <div class="empty-path">
            Your journey will appear here.
        </div>
        """

    nodes = []

    for index, title in enumerate(path):
        node_class = "path-node"

        if index == 0:
            node_class += " start-node"
        elif index == len(path) - 1:
            node_class += " active-node"

        nodes.append(
            f"""
            <div class="{node_class}">
                <span>{index}</span>
                <strong>{escape(title)}</strong>
            </div>
            """
        )

        if index < len(path) - 1:
            nodes.append('<div class="path-line"></div>')

    return f"""
    <div class="path-wrapper">
        {''.join(nodes)}
    </div>
    """


def temperature_message(
    previous_score: float | None,
    new_score: float,
    won: bool,
) -> str:
    if won:
        return "TARGET REACHED"

    if previous_score is None:
        return "SEARCHING"

    difference = new_score - previous_score

    if new_score >= 65:
        return "BURNING HOT"
    if difference >= 18:
        return "MUCH WARMER"
    if difference >= 4:
        return "GETTING WARMER"
    if difference <= -18:
        return "ICE COLD"
    if difference <= -4:
        return "GETTING COLDER"

    return "UNCHANGED"


def victory_screen(path: list[str], target: str) -> str:
    clicks = max(len(path) - 1, 0)

    return f"""
    <section class="victory-panel">
        <div class="victory-icon">◆</div>
        <span class="eyebrow">MISSION COMPLETE</span>
        <h1>You found {escape(target)}!</h1>
        <p>
            You crossed Wikipedia in
            <strong>{clicks} move{"s" if clicks != 1 else ""}</strong>.
        </p>
        <div class="victory-path">
            {escape("  →  ".join(path))}
        </div>
    </section>
    """


def error_outputs(message: str):
    return (
        f"""
        <section class="error-panel">
            <h2>Unable to start this mission</h2>
            <p>{escape(message)}</p>
        </section>
        """,
        "",
        gr.update(choices=[], value=None, interactive=False),
        "",
        [],
        "",
        "",
        0.0,
    )


def load_location(
    article: str,
    target: str,
    path: list[str],
    previous_score: float | None,
):
    resolved_title, summary, links = get_article_data(article)
    target = resolve_article(target)

    if path:
        path[-1] = resolved_title
    else:
        path = [resolved_title]

    link_set = {link.casefold() for link in links}
    score = connection_score(resolved_title, target, link_set)
    won = resolved_title.casefold() == target.casefold()
    temperature = temperature_message(previous_score, score, won)

    header = make_header(
        resolved_title,
        target,
        max(len(path) - 1, 0),
        temperature,
    )

    if won:
        content = victory_screen(path, target)
        destinations = gr.update(
            choices=[],
            value=None,
            interactive=False,
            label="Mission complete",
        )
    else:
        content = make_article_card(resolved_title, summary)
        choices = select_destinations(links, target)

        destinations = gr.update(
            choices=choices,
            value=None,
            interactive=True,
            label="Choose your next destination",
        )

    return (
        header,
        content,
        destinations,
        make_path(path),
        path,
        resolved_title,
        target,
        score,
    )


def start_game(start: str, target: str):
    start = normalize_title(start)
    target = normalize_title(target)

    if not start or not target:
        return error_outputs("Enter both a starting article and a target.")

    try:
        resolved_start = resolve_article(start)
        resolved_target = resolve_article(target)

        return load_location(
            resolved_start,
            resolved_target,
            [resolved_start],
            None,
        )

    except (requests.RequestException, ValueError) as error:
        return error_outputs(str(error))


def travel(
    destination: str,
    target: str,
    path: list[str],
    previous_score: float,
):
    if not destination:
        return (
            gr.update(),
            gr.update(),
            gr.update(),
            gr.update(),
            path,
            path[-1] if path else "",
            target,
            previous_score,
        )

    new_path = list(path)
    new_path.append(destination)

    try:
        return load_location(
            destination,
            target,
            new_path,
            previous_score,
        )

    except (requests.RequestException, ValueError) as error:
        return error_outputs(str(error))


def undo_move(
    target: str,
    path: list[str],
):
    if len(path) <= 1:
        current = path[0] if path else ""

        if not current:
            return error_outputs("Start a mission first.")

        return load_location(
            current,
            target,
            path,
            None,
        )

    new_path = path[:-1]
    previous_article = new_path[-1]

    return load_location(
        previous_article,
        target,
        new_path,
        None,
    )


def load_daily():
    start, target = daily_challenge()
    return start_game(start, target)


def load_random():
    start, target = random_challenge()
    return start_game(start, target)


CSS = """
:root {
    --background: #070b14;
    --panel: #111827;
    --panel-light: #182235;
    --border: rgba(255, 255, 255, 0.09);
    --text: #f7f9fc;
    --muted: #9aa8bd;
    --accent: #7c5cff;
    --accent-bright: #9c88ff;
    --cyan: #4dd7ff;
    --success: #48e3a5;
}

.gradio-container {
    max-width: 1180px !important;
    margin: 0 auto !important;
    padding: 20px !important;
    background:
        radial-gradient(circle at 50% -20%, rgba(124, 92, 255, 0.24), transparent 40%),
        var(--background) !important;
}

body,
.gradio-container {
    font-family: Inter, ui-sans-serif, system-ui, sans-serif !important;
}

footer {
    display: none !important;
}

.hero {
    text-align: center;
    padding: 38px 10px 24px;
}

.hero-badge {
    display: inline-block;
    color: var(--cyan);
    border: 1px solid rgba(77, 215, 255, 0.32);
    background: rgba(77, 215, 255, 0.08);
    border-radius: 999px;
    padding: 7px 13px;
    font-size: 0.74rem;
    font-weight: 800;
    letter-spacing: 0.16em;
}

.hero h1 {
    margin: 16px 0 6px;
    color: var(--text);
    font-size: clamp(2.8rem, 7vw, 5.1rem);
    line-height: 0.95;
    letter-spacing: -0.06em;
}

.hero h1 span {
    color: var(--accent-bright);
}

.hero p {
    color: var(--muted);
    font-size: 1.05rem;
    margin: 15px auto 0;
    max-width: 630px;
}

.setup-panel,
.control-panel {
    background: rgba(17, 24, 39, 0.9);
    border: 1px solid var(--border);
    border-radius: 22px;
    padding: 20px;
    box-shadow: 0 20px 55px rgba(0, 0, 0, 0.28);
}

.setup-panel label span,
.destination-grid label span {
    color: var(--text) !important;
    font-weight: 800 !important;
}

.mission-grid {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 14px;
    align-items: stretch;
    margin: 22px 0 14px;
}

.mission-card {
    min-height: 125px;
    padding: 22px;
    border-radius: 20px;
    background: var(--panel);
    border: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.current-card {
    border-color: rgba(77, 215, 255, 0.35);
}

.target-card {
    border-color: rgba(156, 136, 255, 0.4);
}

.mission-card h2 {
    color: var(--text);
    margin: 6px 0 0;
    font-size: 1.55rem;
}

.mission-arrow {
    display: flex;
    align-items: center;
    color: var(--accent-bright);
    font-size: 2rem;
}

.eyebrow {
    color: var(--muted);
    font-size: 0.7rem;
    font-weight: 900;
    letter-spacing: 0.16em;
}

.game-stats {
    display: flex;
    gap: 10px;
    margin-bottom: 14px;
}

.stat-pill {
    flex: 1;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 15px;
    padding: 13px 17px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.stat-pill strong {
    color: var(--text);
}

.stat-label {
    color: var(--muted);
    font-size: 0.7rem;
    font-weight: 900;
    letter-spacing: 0.12em;
}

.heat-pill strong {
    color: var(--cyan);
}

.article-panel,
.victory-panel,
.error-panel {
    background:
        linear-gradient(135deg, rgba(124, 92, 255, 0.09), transparent 45%),
        var(--panel);
    border: 1px solid var(--border);
    border-radius: 22px;
    padding: clamp(22px, 5vw, 38px);
    margin: 14px 0;
    color: var(--text);
}

.article-heading {
    display: flex;
    gap: 14px;
    align-items: center;
}

.location-pin {
    color: var(--cyan);
    font-size: 1.7rem;
}

.article-panel h1,
.victory-panel h1 {
    color: var(--text);
    margin: 4px 0 0;
    font-size: clamp(1.8rem, 5vw, 2.7rem);
}

.article-panel p {
    color: #c7d0df;
    line-height: 1.75;
    font-size: 1rem;
}

.wiki-link {
    display: inline-block;
    color: var(--cyan) !important;
    font-weight: 750;
    text-decoration: none !important;
    margin-top: 8px;
}

.destination-grid {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 22px;
    padding: 18px !important;
    margin-top: 14px;
}

.destination-grid .wrap {
    display: grid !important;
    grid-template-columns: repeat(3, minmax(0, 1fr)) !important;
    gap: 10px !important;
}

.destination-grid label {
    min-height: 62px !important;
    border: 1px solid var(--border) !important;
    border-radius: 14px !important;
    background: var(--panel-light) !important;
    color: var(--text) !important;
    padding: 14px !important;
    transition:
        transform 160ms ease,
        border-color 160ms ease,
        background 160ms ease !important;
}

.destination-grid label:hover {
    transform: translateY(-2px);
    border-color: rgba(124, 92, 255, 0.8) !important;
    background: rgba(124, 92, 255, 0.16) !important;
}

.primary-button {
    min-height: 52px !important;
    border-radius: 14px !important;
    font-weight: 850 !important;
}

.path-section {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 22px;
    padding: 22px;
    margin-top: 14px;
}

.path-title {
    color: var(--text);
    font-size: 0.78rem;
    letter-spacing: 0.13em;
    font-weight: 900;
    margin-bottom: 18px;
}

.path-wrapper {
    display: flex;
    align-items: center;
    gap: 8px;
    overflow-x: auto;
    padding-bottom: 8px;
}

.path-node {
    min-width: max-content;
    background: var(--panel-light);
    border: 1px solid var(--border);
    border-radius: 999px;
    color: var(--text);
    padding: 8px 13px 8px 8px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.path-node span {
    width: 27px;
    height: 27px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.08);
    color: var(--muted);
    font-size: 0.75rem;
}

.active-node {
    border-color: rgba(77, 215, 255, 0.55);
}

.active-node span {
    background: var(--cyan);
    color: #07101a;
}

.start-node span {
    background: var(--accent);
    color: white;
}

.path-line {
    width: 24px;
    min-width: 24px;
    height: 2px;
    background: rgba(255, 255, 255, 0.14);
}

.victory-panel {
    text-align: center;
    border-color: rgba(72, 227, 165, 0.45);
    background:
        radial-gradient(circle at 50% 0%, rgba(72, 227, 165, 0.19), transparent 48%),
        var(--panel);
}

.victory-icon {
    color: var(--success);
    font-size: 3rem;
    margin-bottom: 10px;
}

.victory-panel p {
    color: var(--muted);
    font-size: 1.05rem;
}

.victory-path {
    color: var(--success);
    background: rgba(72, 227, 165, 0.08);
    border: 1px solid rgba(72, 227, 165, 0.2);
    border-radius: 14px;
    padding: 15px;
    margin-top: 18px;
    overflow-wrap: anywhere;
}

.empty-path {
    color: var(--muted);
}

.error-panel {
    border-color: rgba(255, 100, 120, 0.38);
}

@media (max-width: 760px) {
    .gradio-container {
        padding: 12px !important;
    }

    .mission-grid {
        grid-template-columns: 1fr;
    }

    .mission-arrow {
        justify-content: center;
        transform: rotate(90deg);
        height: 25px;
    }

    .destination-grid .wrap {
        grid-template-columns: 1fr !important;
    }

    .game-stats {
        flex-direction: column;
    }
}
"""


with gr.Blocks(title="WikiQuest") as demo:
    path_state = gr.State([])
    current_state = gr.State("")
    target_state = gr.State("")
    score_state = gr.State(0.0)

    gr.HTML(
        """
        <header class="hero">
            <span class="hero-badge">THE INTERNET RABBIT HOLE</span>
            <h1>WIKI<span>QUEST</span></h1>
            <p>
                Travel between two completely different ideas using only
                the links hidden inside Wikipedia.
            </p>
        </header>
        """
    )

    with gr.Group(elem_classes=["setup-panel"]):
        with gr.Row():
            start_input = gr.Textbox(
                label="Starting article",
                value="Motorcycle",
                placeholder="Example: Motorcycle",
            )

            target_input = gr.Textbox(
                label="Target article",
                value="Black hole",
                placeholder="Example: Black hole",
            )

        with gr.Row():
            start_button = gr.Button(
                "Start Custom Mission",
                variant="primary",
                elem_classes=["primary-button"],
            )

            daily_button = gr.Button(
                "Play Daily Challenge",
                elem_classes=["primary-button"],
            )

            random_button = gr.Button(
                "Generate Random Mission",
                elem_classes=["primary-button"],
            )

    mission_header = gr.HTML()

    article_display = gr.HTML(
        """
        <section class="article-panel">
            <span class="eyebrow">READY FOR DEPARTURE</span>
            <h1>Choose a mission above</h1>
            <p>
                Every destination shown during the game is a real link
                from your current Wikipedia article.
            </p>
        </section>
        """
    )

    destination_picker = gr.Radio(
        label="Choose your next destination",
        choices=[],
        interactive=True,
        elem_classes=["destination-grid"],
    )

    with gr.Row():
        travel_button = gr.Button(
            "Travel to Selected Article",
            variant="primary",
            elem_classes=["primary-button"],
        )

        undo_button = gr.Button(
            "Undo Last Move",
            elem_classes=["primary-button"],
        )

    gr.HTML('<section class="path-section"><div class="path-title">YOUR JOURNEY</div>')

    path_display = gr.HTML(
        '<div class="empty-path">Your journey will appear here.</div>'
    )

    gr.HTML("</section>")

    game_outputs = [
        mission_header,
        article_display,
        destination_picker,
        path_display,
        path_state,
        current_state,
        target_state,
        score_state,
    ]

    start_button.click(
        fn=start_game,
        inputs=[start_input, target_input],
        outputs=game_outputs,
    )

    daily_button.click(
        fn=load_daily,
        outputs=game_outputs,
    )

    random_button.click(
        fn=load_random,
        outputs=game_outputs,
    )

    travel_button.click(
        fn=travel,
        inputs=[
            destination_picker,
            target_state,
            path_state,
            score_state,
        ],
        outputs=game_outputs,
    )

    destination_picker.change(
        fn=travel,
        inputs=[
            destination_picker,
            target_state,
            path_state,
            score_state,
        ],
        outputs=game_outputs,
    )

    undo_button.click(
        fn=undo_move,
        inputs=[
            target_state,
            path_state,
        ],
        outputs=game_outputs,
    )


demo.launch(
    theme=gr.themes.Base(),
    css=CSS,
)