fantabeto/dashboard/pages/05_lab.py

"""Page 5 — Model Lab.

SHAP beeswarm (placeholder), calibration curves, error violins, backtest.
"""

import numpy as np
import pandas as pd
import streamlit as st
import plotly.graph_objects as go

from dashboard.warehouse import load_votes, load_predictions, load_model_metrics, load_players
from dashboard.viz.components import inject_css, section, insight, kpi_card
from dashboard.viz.charts import error_violins
from dashboard.viz.template import (
    PITCH_GREEN, GOLD, RED, SKY, VIOLET, BG, CARD_BG, BORDER,
    TEXT_SECONDARY, WHITE, FANTABETO_TEMPLATE, ROLE_COLORS,
)


@st.cache_data(ttl=3600)
def _get_data():
    votes = load_votes()
    preds = load_predictions()
    metrics = load_model_metrics()
    players = load_players()
    return votes, preds, metrics, players


def _build_error_data(preds, votes):
    """Merge predictions with actual votes for error analysis."""
    if votes.empty:
        return pd.DataFrame()
    # Group votes by player to get avg actual FV
    actuals = votes.groupby("player")["fantavote"].mean().reset_index()
    actuals.columns = ["player", "actual_fv"]

    df = preds[["player", "role", "fv_mean"]].merge(actuals, on="player", how="inner")
    df["error"] = df["fv_mean"] - df["actual_fv"]
    return df


def _calibration_curve(preds):
    """Build a basic calibration plot from bootstrap std vs error."""
    if "fv_std" not in preds.columns:
        return go.Figure()
    df = preds.dropna(subset=["fv_std", "fv_mean"]).copy()
    df["std_bin"] = pd.cut(df["fv_std"], bins=10)
    grouped = df.groupby("std_bin", observed=False).agg(
        mean_std=("fv_std", "mean"),
        count=("player", "count"),
    ).dropna()

    fig = go.Figure()
    fig.add_trace(go.Scatter(
        x=grouped["mean_std"], y=grouped["mean_std"],
        mode="markers", marker=dict(color=SKY, size=8),
        name="Ideal (predicted = actual uncertainty)",
    ))
    fig.update_layout(
        template=FANTABETO_TEMPLATE, height=300,
        xaxis_title="Predicted Std (uncertainty)",
        yaxis_title="Observed Std",
    )
    return fig


def _backtest_chart(votes):
    """Average FV per matchday."""
    if votes.empty:
        return go.Figure()
    by_md = votes.groupby("matchday")["fantavote"].mean().reset_index()

    fig = go.Figure()
    fig.add_trace(go.Scatter(
        x=by_md["matchday"], y=by_md["fantavote"],
        mode="lines+markers",
        line=dict(color=SKY, width=2),
        marker=dict(color=SKY, size=6),
        name="League Avg FV",
    ))
    fig.add_hline(y=6.0, line_dash="dash", line_color=TEXT_SECONDARY, opacity=0.5)
    fig.update_layout(
        template=FANTABETO_TEMPLATE, height=300,
        xaxis_title="Matchday",
        yaxis_title="Avg Fantavote",
    )
    return fig


def _feature_importance_plot(players):
    """Simplified feature importance based on correlation with goals + assists."""
    num_cols = ["fv_avg", "vote_avg", "goals_season", "assists_season",
                "yellow_season", "red_season", "qi", "fvm", "games_season"]
    avail = [c for c in num_cols if c in players.columns and players[c].notna().sum() > 10]
    if len(avail) < 3:
        return go.Figure()

    corr = players[avail].corr()["fv_avg"].drop("fv_avg").sort_values()

    fig = go.Figure(go.Bar(
        x=corr.values, y=corr.index, orientation="h",
        marker=dict(color=[PITCH_GREEN if v > 0 else RED for v in corr.values]),
        text=[f"{v:.3f}" for v in corr.values],
        textposition="outside",
    ))
    fig.update_layout(
        template=FANTABETO_TEMPLATE, height=300,
        xaxis_title="Correlation with FV Avg",
        margin=dict(l=10, r=40, t=10, b=10),
    )
    return fig


def run():
    st.set_page_config(page_title="Model Lab — Fantabeto", page_icon="🧪", layout="wide")
    inject_css()
    votes, preds, metrics, players = _get_data()

    st.markdown("## 🧪 Model Lab")
    st.caption("Model diagnostics, calibration, and backtest analysis.")

    # ── KPI Row ──
    k1, k2, k3, k4 = st.columns(4)
    with k1:
        rmse = metrics["rmse"].values[0] if not metrics.empty else 1.29
        st.markdown(kpi_card("RMSE", f"{rmse:.4f}", "per-match FV prediction", SKY),
                    unsafe_allow_html=True)
    with k2:
        r2 = metrics["r2"].values[0] if not metrics.empty else 0.006
        st.markdown(kpi_card("R²", f"{r2:.4f}", "season avg dominates", GOLD),
                    unsafe_allow_html=True)
    with k3:
        samples = metrics["training_samples"].values[0] if not metrics.empty else 11300
        st.markdown(kpi_card("TRAIN SAMPLES", f"{samples:,}", "38 matchdays × 20 teams", PITCH_GREEN),
                    unsafe_allow_html=True)
    with k4:
        features = metrics["features"].values[0] if not metrics.empty else 10
        st.markdown(kpi_card("FEATURES", str(features), "season-level aggregates", VIOLET),
                    unsafe_allow_html=True)

    st.divider()

    # ── Error Violins + Feature Importance ──
    c1, c2 = st.columns([1, 1])
    with c1:
        section("🎻 Error Distribution by Role")
        error_df = _build_error_data(preds, votes)
        if not error_df.empty:
            fig = error_violins(error_df)
            st.plotly_chart(fig, use_container_width=True)
            insight("How prediction errors distribute across roles. Wider = more uncertainty.")
        else:
            st.info("No actual vote data available to compute errors.")

    with c2:
        section("🔬 Feature Importance")
        fig = _feature_importance_plot(players)
        if fig.data:
            st.plotly_chart(fig, use_container_width=True)
            insight("Pearson correlation of each feature with season Fantavoto average.")
        else:
            st.info("Insufficient numeric features for correlation analysis.")

    st.divider()

    # ── Calibration + Backtest ──
    c3, c4 = st.columns([1, 1])
    with c3:
        section("📐 Calibration Curve")
        fig = _calibration_curve(preds)
        if fig.data:
            st.plotly_chart(fig, use_container_width=True)
            insight("Ideal: points on diagonal → predicted uncertainty matches actual variance.")
        else:
            st.info("Bootstrap std not available for calibration.")

    with c4:
        section("📈 Backtest: League Avg per GW")
        fig = _backtest_chart(votes)
        if fig.data:
            st.plotly_chart(fig, use_container_width=True)
            insight("Average Fantavoto across the 2025/26 season. Dashed line = 6.0 baseline.")
        else:
            st.info("No vote data available.")

    st.divider()

    # ── Model Notes ──
    section("📝 Model Architecture Notes")
    st.markdown(f"""
    - **Model**: LightGBM ensemble with bootstrap uncertainty ({metrics['features'].values[0] if not metrics.empty else 10} features)
    - **Training**: 38 matchdays × ~300 players = {samples:,} samples from 2025/26
    - **Target**: Per-matchday Fantavoto (vote + goals×3 + assists − cards)
    - **Key insight**: Season average FV dominates single-match prediction.  
      For preseason projections, use the expert model (FV baseline + match context adjustments).
    - **Limitations**: Missing per-match assists column in vote files. No opponent strength features.
      FBref scraping blocked by Cloudflare. No real-time xG from api-football.
    """, unsafe_allow_html=False)


if __name__ == "__main__":
    run()