#!/usr/bin/env python3
"""
Adds dn_batches.uploaded_at and backfills it.

PocketBase's own `created` is an empty string on every dn_batches record —
the collection was created without autodate — so the board's "-created"
sort is a no-op and the tick's "oldest first" means nothing. The rest of
this codebase already works around the same quirk (delivery_notes sorts by
date_received), so an explicit field is the consistent fix.

Backfill, in priority order:

  1. The earliest date_received of the delivery_notes linked to the batch.
     That is the document's own date and the most trustworthy source.
  2. A date parsed from the stored filename. These are scanner-generated
     ("cam_scanner_2026_09_10_15", "20260910_144808"), so they are
     unambiguous — but they are the SCAN date, not the upload date. Good
     enough to order a board by; not to be treated as provenance.
  3. Nothing. Left empty rather than invented.

Batches uploaded after this ships get uploaded_at set at upload time, so
this only ever runs against the historical set.

Idempotent. Dry-run by default; pass --apply to write.
"""
import re
import sys

from pb_env import PB, http, superuser_token

# A scanner filename date: 20260910, 2026_09_10, 2026-09-10.
FILENAME_DATE = re.compile(r"(20\d{2})[_-]?(\d{2})[_-]?(\d{2})")


def date_from_filename(filename: str) -> str | None:
    m = FILENAME_DATE.search(filename or "")
    if not m:
        return None
    year, month, day = (int(g) for g in m.groups())
    # Reject a match that is really an invoice or order number.
    if not (2024 <= year <= 2027 and 1 <= month <= 12 and 1 <= day <= 31):
        return None
    return f"{year:04d}-{month:02d}-{day:02d} 00:00:00.000Z"


def get_all(token, coll, fields=None, filt=None):
    out, page = [], 1
    while True:
        q = f"?page={page}&perPage=200"
        if fields:
            q += f"&fields={fields}"
        if filt:
            q += f"&filter={filt}"
        code, resp = http("GET", f"/api/collections/{coll}/records{q}", token=token)
        if code != 200:
            sys.exit(f"GET {coll} failed: {code} {resp}")
        out.extend(resp["items"])
        if page >= resp["totalPages"]:
            return out
        page += 1


def main(apply: bool):
    token = superuser_token()
    print(f"\n→ dn_batches on {PB}  ({'APPLY' if apply else 'DRY RUN'})")

    code, coll = http("GET", "/api/collections/dn_batches", token=token)
    if code != 200:
        sys.exit(f"GET collection failed: {code} {coll}")
    # Read the live field list and APPEND. PocketBase replaces the whole
    # array on PATCH, so building it from anything but a fresh read risks
    # dropping columns.
    fields = list(coll.get("fields", []))
    if any(f.get("name") == "uploaded_at" for f in fields):
        print("  • uploaded_at already exists")
    elif not apply:
        print(f"  would add uploaded_at (preserving {len(fields)} existing fields)")
    else:
        code, resp = http(
            "PATCH",
            f"/api/collections/{coll['id']}",
            {"fields": fields + [{"name": "uploaded_at", "type": "date", "required": False}]},
            token,
        )
        if code != 200:
            sys.exit(f"PATCH failed: {code} {resp}")
        print(f"  ✓ added uploaded_at (kept {len(fields)} existing fields)")

    # Source 1: the earliest date_received among the batch's delivery notes.
    earliest: dict[str, str] = {}
    for d in get_all(token, "delivery_notes", "batch,date_received"):
        batch = d.get("batch")
        received = (d.get("date_received") or "").strip()
        if not batch or not received:
            continue
        if batch not in earliest or received < earliest[batch]:
            earliest[batch] = received

    batches = get_all(token, "dn_batches", "id,uploaded_at,file")
    counts = {"delivery_note": 0, "filename": 0, "left_empty": 0, "already_set": 0}

    for b in batches:
        if (b.get("uploaded_at") or "").strip():
            counts["already_set"] += 1
            continue

        value = earliest.get(b["id"])
        source = "delivery_note"
        if not value:
            value = date_from_filename(b.get("file") or "")
            source = "filename"
        if not value:
            counts["left_empty"] += 1
            print(f"  {'left empty':14s} {'-':24s} {(b.get('file') or '')[:40]}")
            continue

        counts[source] += 1
        print(f"  {source:14s} {value[:10]:24s} {(b.get('file') or '')[:40]}")
        if apply:
            code, resp = http(
                "PATCH",
                f"/api/collections/dn_batches/records/{b['id']}",
                {"uploaded_at": value},
                token,
            )
            if code != 200:
                sys.exit(f"PATCH {b['id']} failed: {code} {resp}")

    print(
        f"\n  from delivery notes: {counts['delivery_note']}"
        f"   from filename: {counts['filename']}"
        f"   left empty: {counts['left_empty']}"
        f"   already set: {counts['already_set']}"
    )
    if not apply:
        print("\n  DRY RUN — nothing written. Re-run with --apply.")


if __name__ == "__main__":
    main("--apply" in sys.argv)
    print("\nDone.")