#!/usr/bin/env python3
"""steps_backfill.py — ONE-OFF (2026-09-24, `09` §6.4 part 5): write `steps/<step_key(to)>.yml` for every
ladder entry that is not the newest, from git history.

WHICH COMMIT, and why not "the commit of the step": the definition a box must pin for a step is the one
the catalog SERVED while that step was the head — the NEWEST commit whose compose images equal the
step's `to`, i.e. the step's images WITH every fix that flowed after they moved. The commit that MOVED
the image can be the broken one: romm's 15f9ebf (5.0.0 -> 5.3.0, 512M, four workers) OOM-looped on
demo-hp; the working definition is the same images under f4eb94f's template (768M, two workers).

Prints one line per step: app, entry, step key, the commit it came from. Never overwrites a step file.
"""
import os
import subprocess
import sys

sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
import ladder  # noqa: E402

ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))


def git(*a):
    return subprocess.run(["git", "-C", ROOT] + list(a), capture_output=True, text=True, check=True).stdout


def main():
    wrote = 0
    for app in sorted(os.listdir(os.path.join(ROOT, "templates"))):
        d = os.path.join(ROOT, "templates", app)
        fy = os.path.join(d, ".felhom.yml")
        if not os.path.isfile(fy):
            continue
        entries, _, errs = ladder.parse(open(fy, encoding="utf-8").read())
        if errs or len(entries) < 2:
            continue
        rel = "templates/%s/docker-compose.yml" % app
        commits = git("log", "--format=%H", "--", rel).split()   # newest first
        for i, e in enumerate(entries[:-1]):
            dst = os.path.join(d, ladder.step_file(e["to"]))
            if os.path.exists(dst):
                print("SKIP  %-10s entry %d: %s exists" % (app, i + 1, ladder.step_file(e["to"])))
                continue
            found = None
            for c in commits:
                body = git("show", "%s:%s" % (c, rel))
                if ladder.images_in(body) == e["to"]:
                    found = (c, body)
                    break          # newest first: the last definition served for this step
            if not found:
                print("MISS  %-10s entry %d: no commit's compose names %s" % (app, i + 1, e["to"]))
                continue
            os.makedirs(os.path.dirname(dst), exist_ok=True)
            open(dst, "w", encoding="utf-8").write(found[1])
            print("WROTE %-10s entry %d/%d -> %s from %s (%s)" % (app, i + 1, len(entries), ladder.step_file(e["to"]),
                                                                 found[0][:12], git("log", "-1", "--format=%s", found[0]).strip()[:70]))
            wrote += 1
    print("steps_backfill: %d step definition(s) written" % wrote)
    return 0


if __name__ == "__main__":
    sys.exit(main())