#!/usr/bin/env python3
"""Run the prune across every historical note and assert it never misbehaves.

The prune is the piece of this system carrying real semantic risk, and 228 real
notes exist to test it against, so this checks invariants rather than relying on
someone eyeballing a diff.
"""

import glob
import os
import sys

sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
from prune import DONE, dropped_indices, parse, subtree_end, top_level_bullets

NOTES = os.path.expanduser("~/docs/notes/todo")


def audit(path):
    lines = parse(open(path).read().split("\n"))
    drop = dropped_indices(lines)
    errs = []

    for i in sorted(drop):
        ln = lines[i]
        if ln.is_heading:
            errs.append(f"removed a heading: {ln.text!r}")
        elif ln.is_bullet and ln.state is not None and ln.state != DONE:
            errs.append(f"removed an unfinished item [{ln.state}]: {ln.text!r}")

    # A dropped subtree must contain at least one checkbox, or it was prose.
    for i in top_level_bullets(lines):
        if i not in drop:
            continue
        end = subtree_end(lines, i)
        if not any(
            lines[j].is_bullet and lines[j].state is not None
            for j in range(i, end + 1)
        ):
            errs.append(f"dropped a checkbox-free subtree: {lines[i].text!r}")

    # A surviving group label must not have lost all of its children.
    for i, ln in enumerate(lines):
        if i in drop or not ln.is_bullet or ln.state is not None:
            continue
        kids = [j for j in range(i + 1, subtree_end(lines, i) + 1) if lines[j].is_bullet]
        if kids and all(j in drop for j in kids):
            errs.append(f"left an emptied group label: {ln.text!r}")

    return lines, drop, errs


def main():
    files = sorted(glob.glob(os.path.join(NOTES, "*.md")))
    if not files:
        sys.exit(f"no notes found under {NOTES}")

    failures = changed = dropped = 0
    kinds = {}
    for f in files:
        lines, drop, errs = audit(f)
        if errs:
            failures += len(errs)
            print(f"FAIL {os.path.basename(f)}")
            for e in errs[:4]:
                print("     ", e)
        if drop:
            changed += 1
            dropped += len(drop)
            for i in drop:
                ln = lines[i]
                k = (
                    f"checkbox[{ln.state}]"
                    if ln.is_bullet and ln.state
                    else "bullet" if ln.is_bullet else "continuation"
                )
                kinds[k] = kinds.get(k, 0) + 1

    print()
    print(f"files          : {len(files)}  ({changed} would change)")
    print(f"lines dropped  : {dropped}")
    for k, v in sorted(kinds.items(), key=lambda x: -x[1]):
        print(f"  {k:>14} : {v}")
    print(f"invariant failures: {failures}")
    return 1 if failures else 0


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