"""Plot construction, colors and color tables shared by radar views."""

import numpy as np
import pyqtgraph as pg
from PyQt6.QtCore import QRectF

from python_app.gui.theme import PLOT_FOREGROUND
from python_app.models.run_config_schema import GprModel
from python_app.models.run_config_validation import parse_position_csv

# Series identity colors in fixed order, checked for the white plot surface: lightness band,
# chroma floor and neighbour separation under normal and colorblind vision. Aqua, yellow and
# pink stay under 3:1 contrast with white, so lines are 2 px wide and the legend names pairs.
SERIES_COLORS = ("#2a78d6", "#eb6834", "#1baf7a", "#eda100", "#e87ba4", "#008300", "#6250d6", "#e34948")
# A captured trace shown on its own (main view, capture preview, PNG export).
CAPTURED_TRACE_PEN = pg.mkPen(SERIES_COLORS[0], width=2)
# Behind legends and labels, so their text stays legible over curves and heatmaps.
OVERLAY_FILL = (255, 255, 255, 200)


def create_plot(title: str = "") -> pg.PlotWidget:
    plot = pg.PlotWidget(enableMenu=False, title=title)
    plot.showGrid(x=True, y=True, alpha=0.2)
    return plot


def build_lut(stops: list[str], *, size: int = 256) -> np.ndarray:
    """Interpolate hex color stops into 8-bit RGB LUT array."""
    stop_positions = np.linspace(0.0, 1.0, num=len(stops), dtype=np.float32)
    sample_positions = np.linspace(0.0, 1.0, num=size, dtype=np.float32)
    stop_colors = np.asarray([pg.mkColor(value).getRgb()[:3] for value in stops], dtype=np.float32)

    lut = np.empty((size, 3), dtype=np.uint8)
    for channel in range(3):
        lut[:, channel] = np.interp(sample_positions, stop_positions, stop_colors[:, channel]).astype(np.uint8)
    return lut


def image_rect(x_axis: np.ndarray, y_axis: np.ndarray) -> QRectF:
    """Rectangle covering image pixels centred on the axis samples; a lone sample spans one unit."""
    (x, width), (y, height) = (_pixel_span(axis) for axis in (x_axis, y_axis))
    return QRectF(x, y, width, height)


def _pixel_span(axis: np.ndarray) -> tuple[float, float]:
    first, last = float(axis[0]), float(axis[-1])
    pitch = (last - first) / (len(axis) - 1) if len(axis) > 1 else 1.0
    return first - pitch / 2, last - first + pitch


# Same Tx/Rx markers (symbol, fill, outline) on ground BP and the three planar SAR views.
ANTENNA_STYLES = (("t", SERIES_COLORS[7], PLOT_FOREGROUND), ("t1", SERIES_COLORS[0], PLOT_FOREGROUND))


def selected_antenna_coordinates(geometry: GprModel, inputs: str, outputs: str) -> tuple[np.ndarray, np.ndarray]:
    selected_inputs, selected_outputs = parse_position_csv(inputs), parse_position_csv(outputs)
    tx = [[row.x_m, row.y_m, row.z_m] for row in geometry.tx_geometry
          if not selected_outputs or row.output_pos in selected_outputs]
    rx = [[row.x_m, row.y_m, row.z_m] for row in geometry.rx_geometry
          if not selected_inputs or row.input_pos in selected_inputs]
    return np.asarray(tx, dtype=float).reshape(-1, 3), np.asarray(rx, dtype=float).reshape(-1, 3)