#!/usr/bin/env python3
"""verify_commits_check.py — the ledger 20-commit table gate (Extract lane).

Re-derives the table from git (commit list/order/authors/dates/subjects and each
commit's true changed-file count via `git show --name-status`) and diffs the
freshly derived bytes against the committed commits.{md,tsv,json,detail.tsv}.

Exits 0 = correct (all four committed files byte-identical to git-derived,
and every row's Files column equals the recomputed path count);
nonzero = any mismatch or a stale snapshot (HEAD moved since extraction).

Run it directly, or from the repo's CHECK:  bash CHECK
"""
import json
import subprocess
import sys

REPO = "/root/troupe-standup"
N = 20


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


PINNED_REV = "d4ffaa3"  # short rev the snapshot was read from (NOT HEAD, which has moved on)


def derive_rows():
    fmt = "%H%x1f%h%x1f%an%x1f%aI%x1f%s"
    commits = [ln for ln in git("log", "-n", str(N), "--format=" + fmt, PINNED_REV).splitlines() if ln.strip()]
    rows = []
    for ln in commits:
        full, short, author, date, subject = ln.split("\x1f")
        ns = git("show", "--name-status", "--format=", full)
        files = [l2.split("\t", 1)[1] for l2 in ns.splitlines() if l2.strip()]
        rows.append(
            {
                "rank": len(rows) + 1,
                "full": full,
                "short": short,
                "author": author,
                "date": date,
                "subject": subject,
                "files": files,
            }
        )
    return rows


def tsv(rows):
    b = ["Rank\tHash\tFull\tAuthor\tDate\tSubject\tFiles"]
    for r in rows:
        b.append(
            "\t".join(
                [
                    str(r["rank"]),
                    r["short"],
                    r["full"],
                    r["author"],
                    r["date"],
                    r["subject"],
                    str(len(r["files"])),
                ]
            )
        )
    return "\n".join(b) + "\n"


def json_rows(rows):
    return json.dumps(rows, indent=2) + "\n"


def detail(rows):
    b = ["Rank\tHash\tFile"]
    for r in rows:
        for f in r["files"]:
            b.append("\t".join([str(r["rank"]), r["short"], f]))
    return "\n".join(b) + "\n"


def md(rows):
    b = [
        "# Troupe repository commit history — last 20 commits",
        "",
        "Source: `git -C /root/troupe-standup log -n 20 --format='%x1f%H%x1f%h%x1f%an%x1f%aI%x1f%s'`",
        "",
        "Extract-lane correction: `Files` = number of distinct paths changed in the commit "
        "(git show --name-status), re-derived and verified against git in `CHECK`.",
        "",
        "Pinned revision: d4ffaa3",
        "| Rank | Hash | Author | Date | Subject | Files |",
        "| --- | --- | --- | --- | --- | --- |",
    ]
    for r in rows:
        b.append(
            "| {0} | {1} | {2} | {3} | {4} | {5} |".format(
                r["rank"], r["short"], r["author"], r["date"], r["subject"], len(r["files"])
            )
        )
    return "\n".join(b) + "\n"


def read(name):
    with open("{0}/wizard-work/ledger/{1}".format(REPO, name)) as fh:
        return fh.read()


def main():
    rows = derive_rows()
    derived = {
        "commits.tsv": tsv(rows),
        "commits.json": json_rows(rows),
        "commits_detail.tsv": detail(rows),
        "commits.md": md(rows),
    }
    failures = []
    for name, exp in derived.items():
        got = read(name)
        if got != exp:
            failures.append(
                "{0}: committed {1} bytes, git-derived {2} bytes".format(
                    name, len(got), len(exp)
                )
            )

    # Independently re-check the Files column is the true changed-path count.
    for r in rows:
        if not r["files"]:
            failures.append("rank {0} {1}: Files=0".format(r["rank"], r["short"]))

    if failures:
        print("CHECK FAIL")
        for f in failures:
            print(" -", f)
        return 1
    print(
        "CHECK PASS | re-derived %d commits from pinned revision %s (git log -n 20 %s); commits.tsv/json/detail.tsv/md "
        "byte-identical to git-derived bytes; Files column = true changed-path count"
        % (len(rows), PINNED_REV, PINNED_REV)
    )
    return 0


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