"""Pure Plotly chart factories, independently testable from Streamlit."""

from __future__ import annotations

from collections.abc import Sequence

import numpy as np
import plotly.graph_objects as go

from .config import FREQ_COLS, LABEL_COLORS, LABEL_DISPLAY, LABEL_ICONS
from .explainability import EngineAnalysis

PLOT_BG = "#101820"
GRID = "rgba(148, 163, 184, 0.14)"
TEXT = "#dce8ee"
MUTED = "#8fa6b2"
COMPARISON_COLORS = ("#28b7d9", "#f5a524", "#38d996", "#d56cff", "#2f78ed")
HEATMAP_DEVIATION_LIMIT_MV = 20.0


def _base_layout(
    fig: go.Figure,
    *,
    height: int,
    margin_top: int = 42,
    margin_bottom: int = 28,
) -> go.Figure:
    fig.update_layout(
        height=height,
        margin=dict(l=24, r=24, t=margin_top, b=margin_bottom),
        paper_bgcolor="rgba(0,0,0,0)",
        plot_bgcolor=PLOT_BG,
        font=dict(color=TEXT, family="Inter, system-ui, sans-serif"),
        hoverlabel=dict(bgcolor="#16232c", font_color="#ffffff"),
    )
    fig.update_xaxes(gridcolor=GRID, zeroline=False)
    fig.update_yaxes(gridcolor=GRID, zeroline=False)
    return fig


def engine_heatmap(analysis: EngineAnalysis) -> go.Figure:
    row_labels = [
        f"{LABEL_ICONS[str(row.label)]} C{int(row.cylinder):02d} · "
        f"{LABEL_DISPLAY[str(row.label)]}"
        for row in analysis.diagnostics.itertuples()
    ]
    fig = go.Figure(
        go.Heatmap(
            z=analysis.deviation,
            x=list(range(len(FREQ_COLS))),
            y=row_labels,
            zmin=-HEATMAP_DEVIATION_LIMIT_MV,
            zmax=HEATMAP_DEVIATION_LIMIT_MV,
            zmid=0,
            colorscale=[
                [0.0, "#28b7d9"],
                [0.5, "#13222b"],
                [1.0, "#ff6b57"],
            ],
            colorbar=dict(title="Δ mV", thickness=12),
            hovertemplate="%{y}<br>%{x} kHz<br>Odchylenie %{z:.1f} mV<extra></extra>",
        )
    )
    fig.update_yaxes(autorange="reversed", automargin=True, title=None)
    fig.update_xaxes(title="Częstotliwość [kHz]", dtick=2)
    return _base_layout(fig, height=360, margin_top=18, margin_bottom=42)


def _cylinder_position(analysis: EngineAnalysis, cylinder: int) -> int:
    positions = np.flatnonzero(analysis.measurements["cylinder"].to_numpy() == cylinder)
    if len(positions) != 1:
        raise KeyError(f"Unknown cylinder={cylinder}")
    return int(positions[0])


def cylinder_spectrum(
    analysis: EngineAnalysis,
    cylinder: int,
    comparison_cylinders: Sequence[int] | None = None,
) -> go.Figure:
    selected = list(
        dict.fromkeys([cylinder, *(comparison_cylinders or ())])
    )
    if len(selected) > 4:
        raise ValueError("At most four cylinders can be compared.")

    position = _cylinder_position(analysis, cylinder)
    row = analysis.diagnostics.iloc[position]
    primary_color = LABEL_COLORS[str(row["label"])]
    frequency = np.arange(len(FREQ_COLS))
    fig = go.Figure()
    fig.add_trace(
        go.Scatter(
            x=frequency,
            y=analysis.reference[position],
            mode="lines",
            name=f"Referencja C{cylinder:02d}",
            line=dict(color="#7f95a1", width=2, dash="dash"),
        )
    )

    extra_colors = iter(
        color
        for color in COMPARISON_COLORS
        if color.lower() != primary_color.lower()
    )
    for selected_cylinder in selected:
        selected_position = _cylinder_position(analysis, selected_cylinder)
        color = primary_color if selected_cylinder == cylinder else next(extra_colors)
        fig.add_trace(
            go.Scatter(
                x=frequency,
                y=analysis.spectra[selected_position],
                mode="lines+markers",
                name=f"C{selected_cylinder:02d}",
                line=dict(
                    color=color,
                    width=3 if selected_cylinder == cylinder else 2,
                ),
                marker=dict(size=6 if selected_cylinder == cylinder else 4),
            )
        )

    top = {
        int(value)
        for value in str(row["top_anomalous_frequencies_khz"]).split("|")
        if value
    }
    for value in top:
        fig.add_vrect(
            x0=value - 0.35,
            x1=value + 0.35,
            fillcolor=primary_color,
            opacity=0.10,
            line_width=0,
        )
    fig.update_layout(
        legend=dict(
            orientation="h",
            x=0,
            xanchor="left",
            y=1.04,
            yanchor="bottom",
        )
    )
    fig.update_xaxes(title="Częstotliwość [kHz]", dtick=1)
    fig.update_yaxes(title="Amplituda [mV]")
    return _base_layout(fig, height=440, margin_top=76, margin_bottom=42)


def deviation_chart(analysis: EngineAnalysis, cylinder: int) -> go.Figure:
    position = int(
        np.flatnonzero(analysis.measurements["cylinder"].to_numpy() == cylinder)[0]
    )
    values = analysis.deviation[position]
    colors = ["#ff6b57" if value >= 0 else "#28b7d9" for value in values]
    fig = go.Figure(
        go.Bar(
            x=np.arange(len(FREQ_COLS)),
            y=values,
            marker_color=colors,
            hovertemplate="%{x} kHz<br>Δ %{y:.1f} mV<extra></extra>",
        )
    )
    fig.add_hline(y=0, line_color="#6e8794", line_width=1)
    fig.update_xaxes(title="Częstotliwość [kHz]", dtick=2)
    fig.update_yaxes(title="Różnica [mV]")
    return _base_layout(fig, height=340, margin_top=24, margin_bottom=42)