# Author: Simon-Pierre Boucher — contact@spboucher.ai
"""Shared matplotlib style for all WP10 figures — print-journal calibre.

Conventions (Journal of Finance house style):
  - no titles inside figures (captions carry the message); multi-panel
    figures use bold "Panel A." headers set flush left above each axes;
  - Times-compatible serif text with STIX math, 8–9 pt;
  - thin, recessive axes (0.6 pt), outward ticks, no top/right spines;
  - one accent hue per figure; a second hue only for genuine polarity or a
    second series, always doubled by a linestyle/marker difference;
  - shaded confidence bands rather than cap-heavy error bars;
  - direct labels instead of legend boxes wherever the geometry allows.

The two data hues (#2e6da4, #c04848) pass the full colour-vision validation
suite (lightness band, chroma floor, CVD separation, contrast) on a white
surface; INK and GREY are reserved for marks-as-ink and reference lines.
"""
import matplotlib

matplotlib.use("Agg")
import matplotlib.pyplot as plt  # noqa: E402

INK = "#1a1a1a"       # primary marks (points, bars, text)
BLUE = "#2e6da4"      # accent series / fitted lines
RED = "#c04848"       # contrast series / polarity
GREY = "#8a8a8a"      # reference lines
LIGHT = "#d9d9d9"     # fills, bands
GRID = "#e3e3e3"      # gridlines

# Sequential blues for ordered series (light → dark, one hue)
BLUES = ["#c6d7e8", "#9dbcd8", "#74a1c8", "#4b86b8", "#2e6da4", "#1d4a75"]

TEXTWIDTH = 6.3       # \textwidth in inches (1in margins, letter paper)


def apply_style() -> None:
    plt.rcParams.update({
        "font.family": "serif",
        "font.serif": ["Times New Roman", "Times", "STIXGeneral", "DejaVu Serif"],
        "mathtext.fontset": "stix",
        "font.size": 9,
        "axes.labelsize": 9,
        "xtick.labelsize": 8,
        "ytick.labelsize": 8,
        "legend.fontsize": 8,
        "figure.dpi": 150,
        "savefig.dpi": 300,
        "axes.spines.top": False,
        "axes.spines.right": False,
        "axes.linewidth": 0.6,
        "xtick.major.width": 0.6,
        "ytick.major.width": 0.6,
        "xtick.major.size": 3,
        "ytick.major.size": 3,
        "xtick.direction": "out",
        "ytick.direction": "out",
        "axes.grid": False,
        "grid.color": GRID,
        "grid.linewidth": 0.5,
        "legend.frameon": False,
        "lines.linewidth": 1.3,
        "lines.markersize": 4.5,
        "figure.constrained_layout.use": False,
    })


def panel_label(ax, text: str) -> None:
    """Bold flush-left panel header above the axes (JoF style)."""
    ax.set_title(text, loc="left", fontsize=9, fontweight="bold", pad=8)


def ygrid(ax) -> None:
    """Recessive horizontal gridlines drawn beneath the data."""
    ax.grid(axis="y", linewidth=0.5, color=GRID)
    ax.set_axisbelow(True)