#!/usr/bin/env python3
"""
issue_ac.py — list and tick the checkboxes in an issue's body. Offline.

    issue_ac.py wire-sqlc-appclick                    numbered list with state
    issue_ac.py wire-sqlc-appclick --check 3          by number
    issue_ac.py wire-sqlc-appclick --check регресс    by substring
    issue_ac.py wire-sqlc-appclick --uncheck 3

A checkbox is the one part of a body that is *state* and not prose. Everything
else is written once; boxes get ticked as the work goes, and until now the only
ways to tick one were a human with an editor or a model rewriting the whole
body — the second worse than the first, because the rewrite re-flows the text
and the issue's diff swells around a change of one character. This changes that
one character and nothing else.

Named after `## Acceptance criteria`, where most boxes live, but every checkbox
in the body is listed and tickable: a type/feature keeps its children under
`## Issues`, and binding this to one heading would silently lose half of them.

A substring picks an item only when it picks exactly one. Two matches is an
error listing both — a coin flip would tick the wrong box and look like it
worked.

Delivering the changed body to a tracker is not part of this: that is
`push.py --update` in /tea:sync.
"""
import argparse
import os
import re
import sys

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

NUMBER = re.compile(r'^\d+$')


def box(c):
    return "[x]" if c.checked else "[ ]"


def listing(items):
    """The numbered list, grouped by the heading each item sits under."""
    out, section = [], None
    for c in items:
        if c.section != section:
            section = c.section
            out.append("")
            out.append(section or "(above the first heading)")
        out.append("  %2d %s %s" % (c.index, box(c), c.text))
    return out


def select(items, needle):
    """Resolve a --check/--uncheck argument to exactly one item, or exit."""
    needle = (needle or "").strip()
    if not needle:
        sys.exit("issue_ac.py: empty selector — give an item number or a substring")
    if NUMBER.match(needle):
        n = int(needle)
        if not 1 <= n <= len(items):
            sys.exit("issue_ac.py: no item %d — the issue has %d" % (n, len(items)))
        return items[n - 1]
    hits = [c for c in items if needle.lower() in c.text.lower()]
    if not hits:
        sys.exit("issue_ac.py: nothing matches %r" % needle)
    if len(hits) > 1:
        sys.exit("\n".join(
            ["issue_ac.py: %r matches %d items — narrow it down, or use a number:"
             % (needle, len(hits))]
            + ["  %2d %s %s" % (c.index, box(c), c.text) for c in hits]))
    return hits[0]


def main(argv=None):
    ap = argparse.ArgumentParser(
        description="List and tick an issue's checkboxes (offline)")
    ap.add_argument("id", help="issue id (the slug, without .md)")
    g = ap.add_mutually_exclusive_group()
    g.add_argument("--check", metavar="N|TEXT", help="tick one item: number or substring")
    g.add_argument("--uncheck", metavar="N|TEXT", help="untick one item: number or substring")
    ap.add_argument("--out", default=issue.ISSUE_ROOT, help="store root (default: tmp/issues)")
    args = ap.parse_args(argv)

    path = issue.path_of(args.out, args.id)
    if not os.path.exists(path):
        sys.exit("issue_ac.py: no issue %r in %s" % (args.id, args.out))
    # newline="": no translation in either direction. Byte-for-byte means the
    # line endings too — reading a CRLF file in text mode and writing it back
    # would rewrite every line while claiming to have changed one character.
    with open(path, newline="") as f:
        text = f.read()

    # The whole file, not just the body: line numbers then point at the file,
    # and the metadata block is rewritten by nobody. Round-tripping through
    # Issue.to_text() would re-render metadata and re-strip the body, which is
    # exactly the byte-level churn this script exists to avoid.
    items = issue.checkboxes(text)
    needle = args.check if args.check is not None else args.uncheck

    if not items:
        if needle is not None:
            sys.exit("issue_ac.py: %s has no checkboxes" % args.id)
        print("%s — no checkboxes" % args.id)
        return 0

    if needle is None:
        done = sum(1 for c in items if c.checked)
        print("%s — %d/%d   %s" % (args.id, done, len(items), path))
        print("\n".join(listing(items)))
        return 0

    checked = args.check is not None
    item = select(items, needle)
    new = issue.set_checkbox(text, item, checked)
    verb = "checked" if checked else "unchecked"
    if new == text:
        print("unchanged  %2d %s %s" % (item.index, box(item), item.text))
        return 0

    with open(path, "w", newline="") as f:
        f.write(new)
    issue_index.build(args.out)

    done, total = issue.checkbox_progress(new)
    print("%s   %2d %s %s" % (verb, item.index, "[x]" if checked else "[ ]", item.text))
    print("%s — %d/%d   %s:%d" % (args.id, done, total, path, item.line))
    return 0


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