figures/make_segment_alignment.py

#!/usr/bin/env python3
"""Figure 1: scope-and-time alignment into atomic local segments."""

from __future__ import annotations

import json
from pathlib import Path

import matplotlib.pyplot as plt
from matplotlib.patches import Rectangle

from style import (
    BLUE,
    FULL_WIDTH_IN,
    INK,
    LIGHT_GREY,
    MID_GREY,
    ORANGE,
    PALE_BLUE,
    PALE_GREY,
    SMALL_TEXT_PT,
    HERE,
    save_figure,
)


SPEC = HERE / "specs" / "segment_example.json"
OUTPUT = HERE / "fig_segment_alignment.pdf"


def load_spec() -> dict:
    data = json.loads(SPEC.read_text(encoding="utf-8"))
    if data.get("schema_version") != "1" or data.get("artifact_status") != "schematic":
        raise ValueError("unexpected segment-example schema or status")
    if data.get("time_points") != [f"t{i}" for i in range(7)]:
        raise ValueError("the figure expects the declared t0,...,t6 cut points")
    if data.get("selected_segment") != [3, 4]:
        raise ValueError("selected segment changed; review the visual specification")
    if [lane["id"] for lane in data["validity_lanes"]] != [
        "inventory",
        "maintenance",
        "reservation",
        "source_validity",
    ]:
        raise ValueError("validity-lane contract changed")
    if [lane["id"] for lane in data["observation_lanes"]] != [
        "activity",
        "fabric",
        "storage",
    ]:
        raise ValueError("observation-lane contract changed")
    return data


def scope_label(value: str) -> str:
    return value.replace(" -> ", " \u2192 ")


def main() -> None:
    data = load_spec()
    fig, ax = plt.subplots(figsize=(FULL_WIDTH_IN, 2.18))
    fig.subplots_adjust(left=0.018, right=0.992, bottom=0.12, top=0.96)

    ax.set_xlim(-2.03, 6.12)
    ax.set_ylim(-0.15, 8.05)
    ax.axis("off")

    # One selected atomic segment, behind every lane.
    ax.add_patch(
        Rectangle(
            (3.0, 0.42),
            1.0,
            7.0,
            facecolor=PALE_BLUE,
            edgecolor="none",
            zorder=0,
        )
    )

    lane_y = {
        "inventory": 7.0,
        "maintenance": 6.0,
        "reservation": 5.0,
        "source_validity": 4.0,
        "activity": 3.0,
        "fabric": 2.0,
        "storage": 1.0,
    }

    # The union of all declared changes forms the segment boundaries.
    for cut in range(7):
        ax.plot(
            [cut, cut],
            [0.42, 7.40],
            color=LIGHT_GREY,
            lw=0.55,
            zorder=1,
        )
        ax.text(
            cut,
            7.55,
            rf"$t_{cut}$",
            ha="center",
            va="bottom",
            fontsize=SMALL_TEXT_PT,
        )

    ax.text(-1.98, 7.55, "record lane", ha="left", va="bottom", fontsize=SMALL_TEXT_PT)
    ax.text(-0.16, 7.55, "scope", ha="right", va="bottom", fontsize=SMALL_TEXT_PT)

    validity_colours = {
        "inventory": PALE_GREY,
        "maintenance": "#F1D9BE",
        "reservation": "#DFE7EC",
        "source_validity": PALE_GREY,
    }
    validity_edges = {
        "inventory": MID_GREY,
        "maintenance": ORANGE,
        "reservation": BLUE,
        "source_validity": MID_GREY,
    }

    for lane in data["validity_lanes"]:
        y = lane_y[lane["id"]]
        ax.text(-1.98, y, lane["label"], ha="left", va="center")
        ax.text(-0.16, y, scope_label(lane["scope"]), ha="right", va="center")
        for start, end, label in lane["intervals"]:
            ax.add_patch(
                Rectangle(
                    (start, y - 0.18),
                    end - start,
                    0.36,
                    facecolor=validity_colours[lane["id"]],
                    edgecolor=validity_edges[lane["id"]],
                    lw=0.75,
                    zorder=2,
                )
            )
            ax.text(
                (start + end) / 2,
                y,
                label,
                ha="center",
                va="center",
                fontsize=SMALL_TEXT_PT,
                zorder=3,
            )

    for lane in data["observation_lanes"]:
        y = lane_y[lane["id"]]
        ax.text(-1.98, y, lane["label"], ha="left", va="center")
        ax.text(-0.16, y, scope_label(lane["scope"]), ha="right", va="center")
        if lane["kind"] == "point":
            positions = lane["positions"]
            if lane["id"] == "storage":
                ax.vlines(positions, y - 0.15, y + 0.15, color=BLUE, lw=1.25, zorder=4)
            else:
                ax.scatter(
                    positions,
                    [y] * len(positions),
                    s=14,
                    marker="o",
                    facecolor=BLUE,
                    edgecolor=BLUE,
                    lw=0.4,
                    zorder=4,
                )
        elif lane["kind"] == "interval":
            for start, end in lane["intervals"]:
                ax.add_patch(
                    Rectangle(
                        (start, y - 0.11),
                        end - start,
                        0.22,
                        facecolor=BLUE,
                        edgecolor=BLUE,
                        lw=0.5,
                        zorder=4,
                    )
                )
        else:
            raise ValueError(f"unsupported observation kind: {lane['kind']}")

    unmapped = data["unmapped_observation"]
    y = lane_y[unmapped["lane"]]
    ax.scatter(
        [unmapped["position"]],
        [y + 0.31],
        s=21,
        marker="x",
        color=MID_GREY,
        lw=0.9,
        zorder=5,
    )
    ax.text(
        unmapped["position"] + 0.055,
        y + 0.31,
        unmapped["label"],
        ha="left",
        va="center",
        color=MID_GREY,
        fontsize=SMALL_TEXT_PT,
    )

    # Segment row: no arrows, only the atomic intervals implied by the cuts.
    ax.text(-1.98, 0.08, "local segments", ha="left", va="center")
    for index in range(6):
        ax.plot([index + 0.04, index + 0.96], [0.08, 0.08], color=INK, lw=0.8)
        ax.text(
            index + 0.5,
            0.08,
            rf"$s_{index + 1}$",
            ha="center",
            va="center",
            fontsize=SMALL_TEXT_PT,
            bbox={"facecolor": "white", "edgecolor": "none", "pad": 0.6},
        )

    save_figure(
        fig,
        OUTPUT,
        subject="Constructed alignment of datacenter records into atomic local segments",
    )


if __name__ == "__main__":
    main()