import html
import json
import os
import re
from glob import glob
from typing import Any, Dict, List

import gradio as gr

# Optional LaTeX → MathML conversion (install: pip install latex2mathml)
try:
    from latex2mathml.converter import convert as _latex_to_mathml
except Exception:  # pragma: no cover
    _latex_to_mathml = None

# Optional Markdown renderer (install: pip install markdown)
try:
    import markdown as _markdown
except Exception:  # pragma: no cover
    _markdown = None

# Precompile math pattern once to avoid recompilation on every render
# Captures four math forms with inner content groups preserved:
# 1) $$ ... $$   → group2
# 2) $ ... $     → group4
# 3) \[ ... \]  → group6
# 4) \( ... \)  → group8
MATH_PATTERN = re.compile(
    r"(\$\$(.*?)\$\$)"  # $$block$$
    r"|(\$([^\$\n]+?)\$)"  # $inline$
    r"|(\\\[(.*?)\\\])"  # \[block\]
    r"|(\\\(([^\n]+?)\\\))",  # \(inline\)
    re.DOTALL,
)


def format_step_content(content: str) -> str:
    """Render content to HTML with Markdown and LaTeX support.

    If the optional `markdown` package is available, we tokenize LaTeX spans,
    render Markdown so headings/lists/emphasis work, then substitute tokens
    with MathML (via latex2mathml). Otherwise, we fall back to escaping with
    inline MathML conversion.

    Args:
        content: Raw text content possibly containing LaTeX snippets.

    Returns:
        Safe HTML string for display.
    """
    if not content:
        return ""

    # Use precompiled regex to capture block and inline math (see MATH_PATTERN above)

    if _markdown is not None:
        # Tokenize math, render Markdown, then substitute tokens with MathML
        parts: list[str] = []
        token_to_html: dict[str, str] = {}
        last_idx = 0
        token_index = 0

        for m in MATH_PATTERN.finditer(content):
            # Non-math prefix: normalize light TeX-ish helpers for MD
            prefix = content[last_idx : m.start()]
            if prefix:
                prefix = re.sub(r"\\text\{([^}]*)\}", r"\1", prefix)
                prefix = re.sub(r"\\emph\{([^}]*)\}", r"*\1*", prefix)
                prefix = re.sub(r"\\Bbb\{([^}]*)\}", r"\\mathbb{\1}", prefix)
                parts.append(prefix)

            # Extract LaTeX
            latex_src = None
            display = False
            if m.group(2) is not None:
                latex_src = m.group(2)
                display = True
            elif m.group(4) is not None:
                latex_src = m.group(4)
                display = False
            elif m.group(6) is not None:
                latex_src = m.group(6)
                display = True
            elif m.group(8) is not None:
                latex_src = m.group(8)
                display = False

            token = f"[[[MATH_TOKEN_{token_index}]]]"
            token_index += 1
            if latex_src is None:
                token_to_html[token] = html.escape(m.group(0)).replace("\n", "<br>")
            else:
                try:
                    if _latex_to_mathml is not None:
                        mathml = _latex_to_mathml(latex_src)
                        if display and mathml.startswith("<math") and " display=" not in mathml:
                            mathml = mathml.replace("<math", '<math display="block"', 1)
                        token_to_html[token] = mathml
                    else:
                        token_to_html[token] = html.escape(m.group(0)).replace("\n", "<br>")
                except Exception:
                    token_to_html[token] = html.escape(m.group(0)).replace("\n", "<br>")

            parts.append(token)
            last_idx = m.end()

        # Trailing non-math
        tail = content[last_idx:]
        if tail:
            tail = re.sub(r"\\text\{([^}]*)\}", r"\1", tail)
            tail = re.sub(r"\\emph\{([^}]*)\}", r"*\1*", tail)
            tail = re.sub(r"\\Bbb\{([^}]*)\}", r"\\mathbb{\1}", tail)
            parts.append(tail)

        text_with_tokens = "".join(parts)
        try:
            html_out = _markdown.markdown(text_with_tokens, extensions=["extra", "sane_lists", "nl2br"])
        except Exception:
            html_out = html.escape(text_with_tokens).replace("\n", "<br>")

        for token, token_html in token_to_html.items():
            html_out = html_out.replace(token, token_html)
        return html_out

    # Fallback: previous approach (safe HTML escaping + optional MathML)
    text = content

    rendered_parts: list[str] = []
    last_idx = 0

    for m in MATH_PATTERN.finditer(text):
        # Add preceding non-math segment (escaped, with mild TeX tweaks)
        prefix = text[last_idx : m.start()]
        if prefix:
            # In non-math, normalize a few TeX-ish helpers
            prefix = re.sub(r"\\text\{([^}]*)\}", r"\1", prefix)
            prefix = re.sub(r"\\emph\{([^}]*)\}", r"<em>\1</em>", prefix)
            prefix = re.sub(r"\\Bbb\{([^}]*)\}", r"\\mathbb{\1}", prefix)
            rendered_parts.append(html.escape(prefix).replace("\n", "<br>"))

        # Determine which group matched and extract LaTeX
        latex_src = None
        display = False
        if m.group(2) is not None:  # $$ ... $$
            latex_src = m.group(2)
            display = True
        elif m.group(4) is not None:  # $ ... $
            latex_src = m.group(4)
            display = False
        elif m.group(6) is not None:  # \[ ... \]
            latex_src = m.group(6)
            display = True
        elif m.group(8) is not None:  # \( ... \)
            latex_src = m.group(8)
            display = False

        if latex_src is None:
            # Should not happen; just append raw match safely
            rendered_parts.append(html.escape(m.group(0)).replace("\n", "<br>"))
        else:
            try:
                mathml = _latex_to_mathml(latex_src)
                # Ensure block math displays as block
                if display and mathml.startswith("<math"):
                    if " display=" not in mathml:
                        mathml = mathml.replace("<math", '<math display="block"', 1)
                rendered_parts.append(mathml)
            except Exception:
                # On failure, fall back to showing the LaTeX literally
                fallback = html.escape(m.group(0)).replace("\n", "<br>")
                rendered_parts.append(fallback)

        last_idx = m.end()

    # Trailing non-math segment
    tail = text[last_idx:]
    if tail:
        tail = re.sub(r"\\text\{([^}]*)\}", r"\1", tail)
        tail = re.sub(r"\\emph\{([^}]*)\}", r"<em>\1</em>", tail)
        tail = re.sub(r"\\Bbb\{([^}]*)\}", r"\\mathbb{\1}", tail)
        rendered_parts.append(html.escape(tail).replace("\n", "<br>"))

    return "".join(rendered_parts)


def create_step_html(step: Dict[str, Any], step_num: int, border_color: str) -> str:
    """Create HTML for a single step (no token counting).

    Args:
        step: The step dictionary to render.
        step_num: 1-based step index.
        border_color: CSS color for the step border.

    Returns:
        HTML string for the step.
    """
    html_out = f"""
    <details style="margin: 8px 0;">
        <summary style="cursor: pointer; color: {border_color}; font-weight: bold;">
            Step {step_num}
        </summary>
        <div style="
            background-color: white;
            border-radius: 6px;
            padding: 12px;
            margin: 8px 0;
            border-left: 4px solid {border_color};
        ">
    """

    observation_text = str(step.get("observation", "")) if step.get("observation") else "None"
    html_out += f"""
    <details style="margin: 8px 0;">
        <summary style="cursor: pointer; color: #666; font-size: 0.9em;">Observation</summary>
        <div style="background-color: #f8f9fa; padding: 8px; border-radius: 4px; margin-top: 4px; color: #333;">
            {format_step_content(observation_text)}
        </div>
    </details>
    """

    thought_text = step.get("thought", "") if step.get("thought") else "None"
    html_out += f"""
    <details style="margin: 8px 0;">
        <summary style="cursor: pointer; color: #666; font-size: 0.9em;">Thought</summary>
        <div style="background-color: #f8f9fa; padding: 8px; border-radius: 4px; margin-top: 4px; color: #333;">
            {format_step_content(thought_text)}
        </div>
    </details>
    """

    action_text = ""
    action = step.get("action")
    if action:
        if isinstance(action, dict) and "action" in action:
            action_text = action["action"]
        else:
            action_text = str(action)

    html_out += f"""
        <div style="margin: 8px 0;">
            <strong style="color: #333;">Action:</strong>
            <div style="background-color: #f8f9fa; padding: 8px; border-radius: 4px; margin-top: 4px; color: #333;">
                {format_step_content(action_text)}
            </div>
        </div>
    """

    reward = step.get("reward", 0.0)
    html_out += f"""
        <div style="margin: 8px 0;">
            <strong style="color: #333;">Reward:</strong> <span style="color: #333;">{reward}</span>
        </div>
    """

    html_out += "</div></details>"
    return html_out


def get_agent_color(agent_name: str) -> tuple[str, str]:
    """Assign a stable color pair to an agent name.

    Args:
        agent_name: Agent identifier string.

    Returns:
        Tuple of (background_color, border_color).
    """
    # Simple stable hash -> hue
    hue = (abs(hash(agent_name)) % 360)
    bg_color = f"hsl({hue}, 40%, 92%)"
    border_color = f"hsl({hue}, 60%, 40%)"
    return bg_color, border_color


def create_trajectory_html(agent_name: str, trajectory: Dict[str, Any]) -> str:
    """Create HTML for a trajectory (no tokenization or chat rendering)."""
    bg_color, border_color = get_agent_color(agent_name)

    agent_display = agent_name

    html_out = f"""
    <div style="
        background-color: {bg_color};
        border-radius: 8px;
        padding: 16px;
        margin: 10px 0;
        border-left: 4px solid {border_color};
    ">
        <div style="font-weight: bold; color: {border_color}; margin-bottom: 10px;">{agent_display}</div>
    """

    steps = trajectory.get("steps", [])
    for i, step in enumerate(steps):
        html_out += create_step_html(step, i + 1, border_color)

    html_out += "</div>"
    return html_out


def create_episode_view(episode: Dict[str, Any]) -> str:
    """Create HTML view for an episode (lightweight).

    Args:
        episode: Episode dictionary to render.

    Returns:
        HTML string.
    """
    episode_id = episode.get("id", "")
    termination_reason = episode.get("termination_reason", "")
    
    html_out = f"""
    <div style="max-width: 1200px; margin: 0 auto; font-family: Arial, sans-serif;">
        <div style="
            background-color: #f8f9fa;
            border-radius: 8px;
            padding: 20px;
            margin-bottom: 20px;
            border-left: 4px solid #007bff;
        ">
            <h2 style="margin: 0 0 12px 0; color: #333;">
                Episode: {episode_id}
            </h2>
            <div style="color:#333; margin-bottom: 16px;">
                <strong>Termination:</strong> <span>{termination_reason}</span>
            </div>
        </div>
    """

    task = episode.get("task", {})
    if task and "question" in task:
        html_out += f"""
        <div style="
            background-color: #e3f2fd;
            border-radius: 8px;
            padding: 16px;
            margin-bottom: 20px;
            border-left: 4px solid #1976d2;
        ">
            <h3 style="margin: 0 0 12px 0; color: #1976d2;">Problem Statement</h3>
            <div style="background-color: white; padding: 12px; border-radius: 4px; color: #333;">
                {format_step_content(task["question"])}
            </div>
        </div>
        """

    html_out += """
        <div style="
            border: 2px solid #ddd;
            border-radius: 8px;
            padding: 20px;
            background-color: white;
        ">
            <h3 style="margin: 0 0 16px 0; color: #333;">Trajectories</h3>
    """

    trajectories = episode.get("trajectories", [])
    for agent_name, trajectory in trajectories:
        html_out += create_trajectory_html(agent_name, trajectory)

    html_out += "</div></div>"
    return html_out


def list_runs(data_dir: str) -> list[str]:
    """List subdirectories inside the data directory.

    Args:
        data_dir: Path to the parent data directory.

    Returns:
        Sorted list of subdirectory names (runs).
    """
    if not data_dir or not os.path.isdir(data_dir):
        return []
    entries = [name for name in os.listdir(data_dir) if os.path.isdir(os.path.join(data_dir, name))]
    return sorted(entries)


def list_episode_files(run_dir: str) -> list[str]:
    """List episode JSON files inside a run directory.

    Args:
        run_dir: Absolute path to a run directory.

    Returns:
        Sorted list of file basenames.
    """
    if not run_dir or not os.path.isdir(run_dir):
        return []
    files = sorted(glob(os.path.join(run_dir, "*.json")))
    return [os.path.basename(p) for p in files]


def load_episode_from_file(file_path: str) -> Dict[str, Any]:
    """Load a single-episode JSON file into a dictionary.

    Args:
        file_path: Absolute path to JSON file containing one episode dict.

    Returns:
        Episode dictionary.
    """
    with open(file_path) as f:
        data = json.load(f)
    # If file accidentally contains a list, take first element
    if isinstance(data, list):
        data = data[0] if data else {}
    return data


def create_gradio_interface(data_dir: str):
    """Create the lightweight viewer with two dropdowns.

    Args:
        data_dir: Parent directory that contains run subdirectories.

    Returns:
        Gradio Blocks app.
    """
    runs = list_runs(data_dir)

    custom_css = """
    /* ─── force global light theme & readable text ─────────────── */
    :root, html, body, #root, .gradio-container{
        background:#ffffff !important;
        color-scheme:light;
        color:#111 !important;
    }
    .gradio-container{
        --body-background-fill:#ffffff;
        --background-fill-primary:#ffffff;
        --background-fill-secondary:#ffffff;
        --block-background-fill:#ffffff;
        --panel-background-fill:#ffffff;
    }

    /* ─── normalize MathML text color to match content ─────────── */
    math, math *{
        color:#333 !important;
        fill:#333 !important;
        stroke:#333 !important;
    }
    """

    with gr.Blocks(title="Simple Episode Viewer", css=custom_css) as demo:
        with gr.Group():
            with gr.Row():
                run_dropdown = gr.Dropdown(choices=runs, value=None, label="Run (subdirectory)")
                episode_dropdown = gr.Dropdown(choices=[], value=None, label="Episode (file)")

        display_area = gr.HTML(label="Episode View", value="<p>Select a run and episode.</p>")

        def update_runs(dir_value: str):
            available_runs = list_runs(dir_value)
            # Start with no run selected by default
            return (
                gr.Dropdown(choices=available_runs, value=None),
                gr.Dropdown(choices=[], value=None),
                "<p>Select a run and episode.</p>",
            )

        def on_run_change(selected_run: str):
            run_path = os.path.join(data_dir, selected_run) if selected_run else None
            episodes = list_episode_files(run_path) if run_path else []
            return gr.Dropdown(choices=episodes, value=(episodes[0] if episodes else None)), "<p>Select an episode.</p>"

        def on_episode_change(selected_episode: str, selected_run: str):
            if not selected_episode or not selected_run:
                return "<p>Select a run and episode.</p>"
            file_path = os.path.join(data_dir, selected_run, selected_episode)
            try:
                episode = load_episode_from_file(file_path)
                return create_episode_view(episode)
            except Exception as e:
                return f"<p>Error loading episode: {html.escape(str(e))}</p>"

        # Wire events
        run_dropdown.change(on_run_change, inputs=[run_dropdown], outputs=[episode_dropdown, display_area])
        episode_dropdown.change(on_episode_change, inputs=[episode_dropdown, run_dropdown], outputs=[display_area])

    return demo


if __name__ == "__main__":
    demo = create_gradio_interface("./data")
    demo.launch()