"""The drawing-lookup job: look drawings up in M-Files (read-only), copy released PDFs into assets, and attach,
flag, stage or open a change order on the packets that use them.

Per run: the queue (drawings/queue.py) cut to `drawing_budget`; per drawing one `Lookup.status`, a fetch when a
released file exists (drawings/fetch.py downloads only when its M-Files identity changed), the `drawing_lookups`
row, then `decide` for every live packet that uses the drawing (its own drawing, or the target of its pending feed
change order), applied through `feed.writes.system_write`. A busy packet is left for the next run.

Never writes to M-Files.
"""

from __future__ import annotations

import logging
from dataclasses import dataclass
from datetime import UTC, datetime
from typing import Any

from psycopg.rows import dict_row
from psycopg.types.json import Jsonb

from ... import audit, policy
from ...domain import pipeline
from ...drawings import DRAWING_FLAGS, decide, queue
from ...drawings import lookup as lookups
from ...drawings.fetch import FetchError, FetchResult, fetch
from ...drawings.lookup import Found, Lookup
from ...feed import changes, writes
from . import Counts, JobContext, JobSpec

log = logging.getLogger(__name__)

A = policy.Action
D = decide

FEED_ORIGINS = ("visual", "drawing")


class _Stale(Exception):
    """The packet changed between the read and the lock; the next run decides again."""


def new_counts() -> Counts:
    return {
        "checked": 0,
        "fetched": 0,
        "unchanged": 0,
        "attached": 0,
        "flagged": {},
        "lookup_failed": 0,
        "cos_opened": 0,
        "cos_reaimed": 0,
        "staged": 0,
        "budget_left": 0,
        "fetch_failed": 0,
        "busy": 0,
        "refused": 0,
        "no_file": 0,
    }


# ---------------------------------------------------------------- the run


def run(ctx: JobContext) -> Counts:
    counts = new_counts()
    fs = ctx.feed_settings
    budget = int(getattr(fs, "drawing_budget", 60))
    try:
        lk = lookups.make(ctx.settings, ctx.stack.cache)
    except Exception as e:  # any failure to open M-Files skips the run
        ctx.error(f"M-Files could not be opened: {type(e).__name__}: {e}")
        counts["reason"] = "mfiles unavailable"
        counts["budget_left"] = budget
        return counts
    now = datetime.now(UTC)
    items = queue.queue(ctx.conn, fs, now, limit=budget)
    counts["budget_left"] = max(0, budget - len(items))
    counts["source"] = lk.describe()
    for item in items:
        try:
            _drawing(ctx, lk, item, counts, now)
        except Exception as e:  # one bad drawing must not stop the others
            log.exception("drawing %s failed", item.dwg)
            ctx.error(f"drawing {item.dwg}: {type(e).__name__}: {e}")
    return counts


def _drawing(ctx: JobContext, lk: Lookup, item: queue.QueueItem, counts: Counts, now: datetime) -> None:
    conn = ctx.conn
    try:
        found = lk.status(item.dwg)
    except Exception as e:  # a lookup error is a failed lookup, never a crash
        found = lookups.failed(item.dwg, f"M-Files lookup failed: {type(e).__name__}: {e}")
    counts["checked"] += 1
    fetched: FetchResult | None = None
    fetch_failed = False
    if found.ok and found.rev is not None:
        try:
            fetched = fetch(conn, ctx.settings, lk, found, dwg=item.dwg)
        except FetchError as e:
            fetch_failed = True
            counts["fetch_failed"] += 1
            ctx.error(str(e))
        else:
            if fetched.downloaded:
                counts["fetched"] += 1
                audit.append(
                    conn,
                    action="drawing.fetched",
                    role_snapshot="system",
                    subject_type="asset",
                    subject_id=str(fetched.asset_id),
                    detail={
                        "dwg": item.dwg,
                        "rev": found.rev,
                        "sha256": fetched.sha256.hex(),
                        "reused": fetched.reused,
                    },
                )
    if not found.ok:
        counts["lookup_failed"] += 1
        ctx.error(f"drawing {item.dwg}: {D.failed_note(found)}")
    vrev_seen = item.visual_rev if item.co_id is None else own_rev(conn, item.dwg)
    save_lookup(conn, item, found, fetched, now, fetch_failed=fetch_failed, visual_rev_seen=vrev_seen)
    scope = [str(d) for d in (getattr(ctx.feed_settings, "departments", None) or [])]
    for pid, relations in sharing(conn, item.dwg, scope):
        _packet(ctx, item.dwg, found, fetched, pid, relations, counts)


# ---------------------------------------------------------------- drawing_lookups


def save_lookup(
    conn: Any,
    item: queue.QueueItem,
    found: Found,
    fetched: FetchResult | None,
    now: datetime,
    *,
    fetch_failed: bool,
    visual_rev_seen: str | None,
) -> None:
    """Upsert the drawing_lookups row for this lookup.

    A failed lookup keeps everything known before (rev, file, asset) and backs off. A good one stores what M-Files
    has; the file identity and the asset are stored together, and cleared when there is no released file or the
    copy failed (so the next run downloads again).
    """
    with conn.transaction():
        prev = conn.execute("SELECT fail_count FROM drawing_lookups WHERE dwg = %s FOR UPDATE", (item.dwg,)).fetchone()
        if not found.ok:
            fails = (int(prev[0]) if prev else 0) + 1
            conn.execute(
                "INSERT INTO drawing_lookups (dwg, checked_at, ok, note, fail_count, failing_since, next_check_at,"
                " visual_rev_seen) VALUES (%(dwg)s, %(now)s, false, %(note)s, %(fails)s, %(now)s, %(next)s, %(vrev)s)"
                " ON CONFLICT (dwg) DO UPDATE SET checked_at = EXCLUDED.checked_at, ok = false, note = EXCLUDED.note,"
                " fail_count = EXCLUDED.fail_count,"
                " failing_since = coalesce(drawing_lookups.failing_since, EXCLUDED.failing_since),"
                " next_check_at = EXCLUDED.next_check_at, visual_rev_seen = EXCLUDED.visual_rev_seen",
                {
                    "dwg": item.dwg,
                    "now": now,
                    "note": D.failed_note(found),
                    "fails": fails,
                    "next": now + queue.backoff(fails),
                    "vrev": visual_rev_seen,
                },
            )
            return
        has_file = fetched is not None
        conn.execute(
            "INSERT INTO drawing_lookups (dwg, checked_at, ok, rev, name, obj_id, obj_version, file_id, file_version,"
            " file_size, base, draft_rev, draft_where, in_drafting, note, fail_count, failing_since, asset_id, sha256,"
            " visual_rev_seen, next_check_at) VALUES (%(dwg)s, %(now)s, true, %(rev)s, %(name)s, %(obj_id)s,"
            " %(obj_version)s, %(file_id)s, %(file_version)s, %(file_size)s, %(base)s, %(draft_rev)s,"
            " %(draft_where)s, %(in_drafting)s, %(note)s, 0, NULL, %(asset_id)s, %(sha)s, %(vrev)s, %(next)s)"
            " ON CONFLICT (dwg) DO UPDATE SET checked_at = EXCLUDED.checked_at, ok = true, rev = EXCLUDED.rev,"
            " name = EXCLUDED.name, obj_id = EXCLUDED.obj_id, obj_version = EXCLUDED.obj_version,"
            " file_id = EXCLUDED.file_id, file_version = EXCLUDED.file_version, file_size = EXCLUDED.file_size,"
            " base = EXCLUDED.base, draft_rev = EXCLUDED.draft_rev, draft_where = EXCLUDED.draft_where,"
            " in_drafting = EXCLUDED.in_drafting, note = EXCLUDED.note, fail_count = 0, failing_since = NULL,"
            " asset_id = EXCLUDED.asset_id, sha256 = EXCLUDED.sha256,"
            " visual_rev_seen = coalesce(EXCLUDED.visual_rev_seen, drawing_lookups.visual_rev_seen),"
            " next_check_at = EXCLUDED.next_check_at",
            {
                "dwg": item.dwg,
                "now": now,
                "rev": found.rev,
                "name": found.name,
                "obj_id": found.obj_id if has_file else None,
                "obj_version": found.obj_version if has_file else None,
                "file_id": found.file_id if has_file else None,
                "file_version": found.file_version if has_file else None,
                "file_size": found.file_size,
                "base": found.base,
                "draft_rev": found.draft_rev,
                "draft_where": found.draft_where or None,
                "in_drafting": found.in_drafting,
                "note": found.note or None,
                "asset_id": fetched.asset_id if fetched else None,
                "sha": fetched.sha256 if fetched else None,
                "vrev": visual_rev_seen,
                "next": now + queue.backoff(1) if fetch_failed else None,
            },
        )


# ---------------------------------------------------------------- packets


def own_rev(conn: Any, dwg: str) -> str | None:
    """The rev a live VISUAL packet with this drawing carries (for visual_rev_seen when the item came from a CO)."""
    row = conn.execute(
        "SELECT coalesce(btrim(rev), '') FROM packets WHERE removed_at IS NULL AND source_kind = 'visual'"
        " AND status <> 'filed' AND btrim(drawing) = %s ORDER BY id LIMIT 1",
        (dwg,),
    ).fetchone()
    return None if row is None else str(row[0])


SHARING_SQL = """
SELECT p.id, 'own' AS rel FROM packets p
WHERE p.removed_at IS NULL AND p.source_kind = 'visual' AND p.status <> 'filed' AND btrim(p.drawing) = %(dwg)s
  AND (cardinality(%(depts)s::text[]) = 0 OR p.dept_code = ANY(%(depts)s::text[]))
UNION
SELECT p.id, 'co' AS rel FROM change_orders c JOIN packets p ON p.id = c.packet_id
WHERE c.review = 'pending' AND c.origin IN ('visual', 'drawing') AND jsonb_typeof(c.waiting) = 'object'
  AND btrim(c.waiting->>'dwg') = %(dwg)s AND p.removed_at IS NULL AND p.status NOT IN ('draft', 'filed')
  AND (cardinality(%(depts)s::text[]) = 0 OR p.dept_code = ANY(%(depts)s::text[]))
ORDER BY 1
"""


def sharing(conn: Any, dwg: str, depts: list[str]) -> list[tuple[int, set[str]]]:
    """Live packets that use the drawing: as their own drawing ('own') or as a pending feed CO's target ('co')."""
    out: dict[int, set[str]] = {}
    for pid, rel in conn.execute(SHARING_SQL, {"dwg": dwg, "depts": depts}).fetchall():
        out.setdefault(int(pid), set()).add(str(rel))
    return sorted(out.items())


@dataclass
class PacketFacts:
    row: dict[str, Any]
    visual: dict[str, Any]
    attached_rev: str | None
    attached_shas: set[bytes]
    co: dict[str, Any] | None
    rejected_sha: bytes | None


def _sha(value: Any) -> bytes | None:
    if not isinstance(value, str) or not value:
        return None
    try:
        return bytes.fromhex(value)
    except ValueError:
        return None


def facts(conn: Any, pid: int) -> PacketFacts | None:
    with conn.cursor(row_factory=dict_row) as cur:
        row = cur.execute(
            "SELECT id, status::text AS status, drawing, rev, drawing_state::text AS drawing_state, flags, visual,"
            " version FROM packets WHERE id = %s AND removed_at IS NULL",
            (pid,),
        ).fetchone()
        if row is None:
            return None
        pages = cur.execute(
            "SELECT pg.rev, a.sha256 FROM packet_pages pg LEFT JOIN assets a ON a.id = pg.asset_id"
            " WHERE pg.packet_id = %s AND pg.type = 'drawing' AND pg.void_at IS NULL ORDER BY pg.n",
            (pid,),
        ).fetchall()
        co = cur.execute(
            "SELECT id, co_no, origin::text AS origin, waiting, staged FROM change_orders"
            " WHERE packet_id = %s AND review = 'pending' AND origin IN ('visual', 'drawing') ORDER BY id DESC LIMIT 1",
            (pid,),
        ).fetchone()
        rej = cur.execute(
            "SELECT staged FROM change_orders WHERE packet_id = %s AND origin = 'drawing' AND review = 'rejected'"
            " ORDER BY id DESC LIMIT 1",
            (pid,),
        ).fetchone()
    visual = row["visual"] if isinstance(row["visual"], dict) else {}
    attached_rev = None
    if pages:
        attached_rev = str(pages[0]["rev"] or "").strip()
    shas = {bytes(p["sha256"]) for p in pages if p["sha256"] is not None}
    rejected = None
    if rej is not None and isinstance(rej["staged"], dict):
        rejected = _sha(rej["staged"].get("sha256"))
    return PacketFacts(dict(row), dict(visual), attached_rev, shas, dict(co) if co else None, rejected)


def _dwg_rev(value: Any) -> tuple[str, str] | None:
    if isinstance(value, dict) and value.get("dwg") and value.get("rev") is not None:
        return (str(value["dwg"]).strip(), str(value["rev"]).strip())
    return None


def target_for(dwg: str, pf: PacketFacts, *, own: bool) -> D.Target:
    row, visual, co = pf.row, pf.visual, pf.co
    waiting = co.get("waiting") if co else None
    staged = co.get("staged") if co else None
    co_waiting = _dwg_rev(waiting)
    co_staged = _dwg_rev(staged)
    packet_rev = str(row["rev"] or "").strip()
    rev_ok = None
    ro = visual.get("rev_ok")
    if isinstance(ro, dict) and ro.get("rev") is not None and str(ro.get("vis_rev") or "").strip() == packet_rev:
        rev_ok = str(ro["rev"]).strip()
    visual_rev = packet_rev if own or co_waiting is None else co_waiting[1]
    return D.Target(
        dwg=dwg,
        visual_rev=visual_rev,
        attached_rev=pf.attached_rev,
        attached_sha=next(iter(sorted(pf.attached_shas)), None),
        status=str(row["status"]),
        drawing_state=str(row["drawing_state"]),
        has_hand_drawing=row["drawing_state"] == "hand" or bool(visual.get("manual_dwg")),
        rev_ok=rev_ok,
        co_waiting=co_waiting,
        co_staged=co_staged,
        co_pending=co is not None,
        co_staged_sha=_sha(staged.get("sha256")) if isinstance(staged, dict) else None,
        rejected_sha=pf.rejected_sha,
    )


def appr_of(t: D.Target, f: Found, now: datetime) -> dict[str, Any]:
    return {
        "ok": f.ok,
        "rev": f.rev,
        "vrev": t.visual_rev,
        "name": f.name,
        "note": f.note or "",
        "base": f.base,
        "draft_rev": f.draft_rev,
        "draft_where": f.draft_where,
        "in_drafting": f.in_drafting,
        "at": now.isoformat(),
    }


def _same_appr(a: Any, b: dict[str, Any]) -> bool:
    if not isinstance(a, dict):
        return False
    return {k: v for k, v in a.items() if k != "at"} == {k: v for k, v in b.items() if k != "at"}


def new_flags(flags: list[str], d: D.Decision) -> list[str]:
    """Every flag but the drawing ones, then the decision's flag."""
    out = [f for f in flags if f not in DRAWING_FLAGS]
    if d.flag and d.flag not in out:
        out.append(d.flag)
    return out


def _packet(
    ctx: JobContext,
    dwg: str,
    found: Found,
    fetched: FetchResult | None,
    pid: int,
    relations: set[str],
    counts: Counts,
) -> None:
    conn = ctx.conn
    pf = facts(conn, pid)
    if pf is None:
        return
    own = "own" in relations
    t = target_for(dwg, pf, own=own)
    same_file = fetched is not None and fetched.sha256 in pf.attached_shas
    d = D.decide(t, found, same_file=same_file, fetched_sha=fetched.sha256 if fetched else None)
    if not own and d.kind != D.STAGE_FOR_CO:
        return  # only the CO's target drawing: nothing to do until it can be staged
    if d.kind in (D.ATTACH, D.OPEN_CO, D.STAGE_FOR_CO) and fetched is None:
        counts["no_file"] += 1  # the copy failed this run; try again next run
        return
    now = datetime.now(UTC)
    row, visual = pf.row, pf.visual
    flags = list(row["flags"] or [])
    flags_after = new_flags(flags, d) if own else flags
    patch: dict[str, Any] = {}
    if own:
        appr = appr_of(t, found, now)
        if not _same_appr(visual.get("appr"), appr):
            patch["appr"] = appr
        if found.ok:
            confirmed = D.rev_confirmed(t, found)
            if bool(visual.get("rev_confirmed")) != confirmed:
                patch["rev_confirmed"] = confirmed
    state_after = d.drawing_state if own else str(row["drawing_state"])
    material = (
        d.kind in (D.ATTACH, D.OPEN_CO, D.STAGE_FOR_CO)
        or flags_after != flags
        or state_after != row["drawing_state"]
        or bool(patch)
    )
    if not material:
        counts["unchanged"] += 1
        return
    action = A.VIS_UPDATE_DRAFT if row["status"] == "draft" else A.VIS_OPEN_CO
    label, note = "Drawing status from M-Files", d.note or None
    if d.kind == D.ATTACH and fetched is not None:
        label = "Drawing attached from M-Files"
        note = "; ".join(x for x in (fetched.name or found.name or "", d.note) if x) or None
    detail = {"dwg": dwg, "rev": found.rev, "kind": d.kind, "asset_id": str(fetched.asset_id) if fetched else None}
    try:
        with writes.system_write(conn, pid, action, label=label, note=note, detail=detail) as sw:
            if int(sw.packet["version"]) != int(row["version"]):
                raise _Stale
            if d.kind == D.ATTACH and fetched is not None:
                _attach(sw, pid, dwg, found, fetched, d, flags_after, patch, now)
                counts["attached"] += 1
            else:
                _status(sw, pid, state_after, flags_after, patch)
                if d.flag:
                    fl = counts["flagged"]
                    fl[d.kind] = fl.get(d.kind, 0) + 1
                if d.kind == D.OPEN_CO and fetched is not None:
                    _open_co(sw, t, dwg, found, fetched, d, counts)
                elif d.kind == D.STAGE_FOR_CO and fetched is not None and pf.co is not None:
                    _stage(sw, pf.co, dwg, found, fetched)
                    counts["staged"] += 1
                elif d.kind == D.UNCHANGED:
                    counts["unchanged"] += 1
    except (_Stale, writes.Busy, writes.Missing):
        counts["busy"] += 1
    except writes.Refused as e:
        counts["refused"] += 1
        ctx.error(f"packet {pid}: {d.kind} refused: {e}", degrade=False)


def _staged(dwg: str, found: Found, fetched: FetchResult) -> dict[str, Any]:
    return {
        "asset_id": str(fetched.asset_id),
        "name": fetched.name or found.name,
        "rev": str(found.rev),
        "dwg": dwg,
        "sha256": fetched.sha256.hex(),
        "pages": fetched.pages,
    }


def _attach(
    sw: Any,
    pid: int,
    dwg: str,
    found: Found,
    fetched: FetchResult,
    d: D.Decision,
    flags: list[str],
    patch: dict[str, Any],
    now: datetime,
) -> None:
    conn = sw.conn
    pages = max(1, int(fetched.pages))
    conn.execute("DELETE FROM packet_pages WHERE packet_id = %s AND type = 'drawing'", (pid,))
    n0 = pipeline.next_counter(conn, pid, "page", pages)
    rev = str(found.rev)
    with conn.cursor() as cur:
        cur.executemany(
            "INSERT INTO packet_pages (packet_id, n, type, asset_id, pn, dwg, rev) VALUES (%s, %s, 'drawing', %s, %s,"
            " %s, %s)",
            [(pid, n0 + i, fetched.asset_id, i + 1, dwg, rev) for i in range(pages)],
        )
    vault = {
        "asset_id": str(fetched.asset_id),
        "name": fetched.name or found.name,
        "rev": found.rev,
        "note": d.note,
        "at": now.isoformat(),
    }
    merged = {**patch, "rev_confirmed": True, "vault": vault}
    conn.execute(
        "UPDATE packets SET drawing_state = 'attached', flags = %s, visual = (visual - 'manual_dwg') || %s"
        " WHERE id = %s",
        (flags, Jsonb(merged), pid),
    )
    sw.changed("pages", "drawing_state", "flags", "visual")


def _status(sw: Any, pid: int, state: str, flags: list[str], patch: dict[str, Any]) -> None:
    sw.conn.execute(
        "UPDATE packets SET drawing_state = %s::drawing_state, flags = %s, visual = visual || %s WHERE id = %s",
        (state, flags, Jsonb(patch), pid),
    )
    sw.changed("drawing_state", "flags", "visual")


def _open_co(sw: Any, t: D.Target, dwg: str, found: Found, fetched: FetchResult, d: D.Decision, counts: Counts) -> None:
    vis = {
        "from_dwg": dwg,
        "to_dwg": dwg,
        "dwg": dwg,
        "from_rev": t.attached_rev,
        "to_rev": str(found.rev),
        "dwg_change": True,
        "changes": [d.note],
    }
    res = changes.open_or_reaim(
        sw,
        origin="drawing",
        reason=d.note,
        vis=vis,
        waiting=None,
        staged=_staged(dwg, found, fetched),
        target_fp=None,
        minor=False,
    )
    # open_or_reaim writes the packet_log label itself
    counts["cos_opened" if res.fresh else "cos_reaimed"] += 1


def _stage(sw: Any, co: dict[str, Any], dwg: str, found: Found, fetched: FetchResult) -> None:
    staged = _staged(dwg, found, fetched)
    sw.conn.execute(
        "UPDATE change_orders SET staged = %s, waiting = NULL, row_version = row_version + 1"
        " WHERE id = %s AND review = 'pending'",
        (Jsonb(staged), co["id"]),
    )
    sw.changed("change_orders")
    sw.log(f"Drawing for change order {co['co_no']} ready for Clerical", staged["name"])


def _cadence(fs: Any, now: datetime) -> int | None:
    return int(fs.drawing_interval_minutes) * 60


SPEC = JobSpec(name="drawing-lookup", run=run, cadence=_cadence, pausable=True)

__all__ = ["SPEC", "new_flags", "run", "save_lookup", "sharing", "target_for"]