#!/usr/bin/env python3
"""Assemble index.html from the template, the inventory and the diagrams.

index.html is self-contained on purpose: it opens from the filesystem with no
server, and a browser at file:// refuses to fetch a sibling JSON. So the
inventory, every .mmd source and every rendered .svg are inlined here rather
than loaded at runtime.

Run it through docs/architecture/render.sh, which re-renders the SVGs first.
Running it alone rebuilds the viewer against whatever SVGs are already there.
"""
import json
import os

import yaml

HERE = os.path.dirname(os.path.abspath(__file__))
DIA = os.path.join(HERE, "diagrams")
CAPDIR = os.path.join(os.path.dirname(HERE), "capabilities")


def main() -> None:
    arch = json.load(open(os.path.join(HERE, "maven-architecture.json")))
    mermaid, svg = {}, {}
    for name in sorted(os.listdir(DIA)):
        path = os.path.join(DIA, name)
        if name.endswith(".mmd"):
            mermaid[name] = open(path).read()
        elif name.endswith(".svg"):
            svg[name] = open(path).read()

    # The capability half. Generated beside this one and read here rather than
    # re-derived: the ledger's build is the only thing allowed to decide a
    # dimension, and a second derivation would drift from it silently.
    ledger = yaml.safe_load(open(os.path.join(CAPDIR, "ledger.yaml")))
    invariants = yaml.safe_load(
        open(os.path.join(CAPDIR, "invariants.yaml")))["invariants"]

    payload = (
        "const ARCH = " + json.dumps(arch, ensure_ascii=False) + ";\n"
        "const CAPS = " + json.dumps(ledger, ensure_ascii=False) + ";\n"
        "const INV = " + json.dumps(invariants, ensure_ascii=False) + ";\n"
        "const MERMAID = " + json.dumps(mermaid, ensure_ascii=False) + ";\n"
        "const SVG = " + json.dumps(svg, ensure_ascii=False) + ";\n"
    )
    template = open(os.path.join(HERE, "viewer.template.html")).read()
    if "/*__DATA__*/" not in template:
        raise SystemExit("viewer.template.html has no /*__DATA__*/ marker")
    out = os.path.join(HERE, "index.html")
    open(out, "w").write(template.replace("/*__DATA__*/", payload))
    print(
        "index.html: %d bytes, %d components, %d relations, %d diagrams, "
        "%d rendered, %d capabilities, %d invariants"
        % (os.path.getsize(out), len(arch["components"]), len(arch["edges"]),
           len(mermaid), len(svg), len(ledger["capabilities"]), len(invariants))
    )


if __name__ == "__main__":
    main()