"""The department checklists and the Q.C. checks, ported from the old checklistFor(), qcChecksFor() and qcMissing().

Each shop department has its own checklist (change C8, Gitea issue 23): the settings row `checklist:<dept code>` holds
{"items": [{group, key, text}]}, edited by that department's supervisor or by Admin. A department without its own
list uses the default for its kind: the welding list for a weld department, else the plain list, from the settings row
`checklist_templates` (migration 0006, Admin edits it) and, when that row is missing or bad, from the defaults here.
A stage freezes its department's list when work starts on it (`packet_stages.checklist_template`, migration 0011), so
a change reaches only stages not yet started. The drawing, rev and WPS are filled into the text at read time.
The Q.C. check items live in the settings row `qc_check_items` (migration 0007); they are not per department.
The keys are the old keys, so a checklist stored as {key: {done, at, by, stamp}} reads the same.
"""

from __future__ import annotations

import logging
import re
from collections.abc import Iterable, Mapping
from typing import Any

from psycopg.types.json import Jsonb

log = logging.getLogger(__name__)

NO_REV = "-"
NDE_NONE = ("", "none", "none required")
NDE_OK = ("acceptable", "accept", "accepted")
REJECTS = ("reject", "rejected")


def _item(group: str, key: str, text: str) -> dict[str, str]:
    return {"group": group, "key": key, "text": text}


DWG_TEXT = "Drawing {drawing} Rev {rev} matches the packet"

# The defaults. The settings row `checklist_templates` holds the same lists (migration 0006); these are the fallback
# when that row is missing or does not parse.
DEFAULT_TEMPLATES: dict[str, list[dict[str, str]]] = {
    "weld": [
        _item("Before welding", "dwg", DWG_TEXT),
        _item("Before welding", "heat", "Heat numbers on material match the Materials tab"),
        _item("Before welding", "wps", "WPS reviewed: {wps}"),
        _item("Before welding", "fit", "Fit-up and dimensions checked against the drawing"),
        _item("Before welding", "pre", "Preheat and interpass temperature per WPS"),
        _item("After welding", "vt", "Visual inspection of all welds acceptable"),
        _item("After welding", "stamp", "Welds stamped with welder ID"),
        _item("After welding", "clean", "Slag and spatter removed"),
        _item("After welding", "qty", "Completed quantity matches each work order"),
    ],
    "plain": [
        _item("Before starting", "dwg", DWG_TEXT),
        _item("Before starting", "prev", "Previous department's work complete and released"),
        _item("Before starting", "mat", "Material and parts on hand match the packet"),
        _item("When done", "work", "Work completed per drawing and procedure"),
        _item("When done", "insp", "Self-inspection done; no damage to finished surfaces"),
        _item("When done", "qty", "Completed quantity matches each work order"),
    ],
}
SETTINGS_KEY = "checklist_templates"
RX_KEY = re.compile(r"^[a-z][a-z0-9_]{0,29}$")
RX_PLACEHOLDER = re.compile(r"\{(drawing|rev|wps)\}")
TEXT_MAX = 200
ITEMS_MAX = 40


def _valid_list(value: Any) -> list[dict[str, str]] | None:
    """A template list from settings, or None when it does not have the right shape."""
    if not isinstance(value, list) or not value or len(value) > ITEMS_MAX:
        return None
    out: list[dict[str, str]] = []
    seen: set[str] = set()
    for it in value:
        if not isinstance(it, Mapping):
            return None
        group, key, text = it.get("group"), it.get("key"), it.get("text")
        if not (isinstance(group, str) and isinstance(key, str) and isinstance(text, str)):
            return None
        if not RX_KEY.match(key) or key in seen or not group.strip() or not text.strip():
            return None
        seen.add(key)
        out.append(_item(group.strip()[:TEXT_MAX], key, text.strip()[:TEXT_MAX]))
    return out


def parse_templates(value: Any) -> dict[str, list[dict[str, str]]] | None:
    """The `checklist_templates` settings value, checked. None when it is malformed."""
    if not isinstance(value, Mapping):
        return None
    weld, plain = _valid_list(value.get("weld")), _valid_list(value.get("plain"))
    if weld is None or plain is None:
        return None
    return {"weld": weld, "plain": plain}


def load_templates(conn: Any) -> dict[str, list[dict[str, str]]]:
    """The department checklists from settings, else the defaults in code (with a warning when the row is bad)."""
    row = conn.execute("SELECT value FROM settings WHERE key = %s", (SETTINGS_KEY,)).fetchone()
    if row is None:
        return DEFAULT_TEMPLATES
    parsed = parse_templates(row[0])
    if parsed is None:
        log.warning("settings %s does not parse; using the default checklists", SETTINGS_KEY)
        return DEFAULT_TEMPLATES
    return parsed


RX_BRACES = re.compile(r"\{[^{}]*\}")
ALLOWED_PLACEHOLDERS = ("{drawing}", "{rev}", "{wps}")


def check_list(name: str, items: Any) -> tuple[list[dict[str, str]] | None, list[str]]:
    """One checklist from an editor, cleaned, and one error line per problem (`name` starts each line). None when
    it is not a list."""
    errors: list[str] = []
    if not isinstance(items, list) or not items:
        return None, [f"{name}: at least one item"]
    if len(items) > ITEMS_MAX:
        errors.append(f"{name}: at most {ITEMS_MAX} items")
    seen: set[str] = set()
    clean: list[dict[str, str]] = []
    for i, it in enumerate(items, start=1):
        where = f"{name} item {i}"
        if not isinstance(it, Mapping):
            errors.append(f"{where}: must be an object with group, key and text")
            continue
        group = " ".join(str(it.get("group") or "").split())
        key = str(it.get("key") or "").strip()
        text = " ".join(str(it.get("text") or "").split())
        if not RX_KEY.match(key):
            errors.append(f"{where}: the key is a lower-case letter, then letters, digits or _ (at most 30)")
        elif key in seen:
            errors.append(f"{where}: key {key} is used twice")
        seen.add(key)
        if not group:
            errors.append(f"{where}: the group is empty")
        if not text:
            errors.append(f"{where}: the text is empty")
        if len(group) > TEXT_MAX or len(text) > TEXT_MAX:
            errors.append(f"{where}: at most {TEXT_MAX} characters")
        bad = [m for m in RX_BRACES.findall(text) if m not in ALLOWED_PLACEHOLDERS]
        stray = RX_BRACES.sub("", text)
        if bad:
            errors.append(f"{where}: unknown placeholder {', '.join(bad)} (use {{drawing}}, {{rev}} or {{wps}})")
        elif "{" in stray or "}" in stray:
            errors.append(f"{where}: a brace without its pair")
        clean.append(_item(group, key, text))
    return clean, errors


# ---------------------------------------------------------------- per department (change C8)

DEPT_PREFIX = "checklist:"


def dept_key(code: str) -> str:
    """The settings key of one department's own checklist."""
    return f"{DEPT_PREFIX}{code}"


def load_dept(conn: Any, code: str) -> tuple[list[dict[str, str]] | None, int]:
    """A department's own checklist and the row's version: (None, 0) when it never had one, (None, version) when it
    was set back to the default (`{"items": null}`) or the row does not parse (with a warning). The default for its
    kind applies then."""
    row = conn.execute("SELECT value, version FROM settings WHERE key = %s", (dept_key(code),)).fetchone()
    if row is None:
        return None, 0
    value = row[0]
    if isinstance(value, Mapping) and value.get("items") is None:
        return None, int(row[1])  # set back to the default for its kind
    items = _valid_list(value.get("items")) if isinstance(value, Mapping) else None
    if items is None:
        log.warning("settings %s does not parse; using the default checklist", dept_key(code))
    return items, int(row[1])


def dept_weld(conn: Any, code: str) -> bool:
    row = conn.execute("SELECT weld FROM departments WHERE code = %s", (code,)).fetchone()
    return bool(row and row[0])


def default_for(conn: Any, weld: bool) -> list[dict[str, str]]:
    """The default list for a department kind (weld or plain): Admin's `checklist_templates`, else the code's."""
    return load_templates(conn)["weld" if weld else "plain"]


def live_list(conn: Any, code: str, weld: bool | None = None) -> list[dict[str, str]]:
    """The department's live checklist: its own list, else the default for its kind."""
    own, _ = load_dept(conn, code)
    if own is not None:
        return own
    return default_for(conn, dept_weld(conn, code) if weld is None else weld)


def as_templates(items: list[dict[str, str]]) -> dict[str, list[dict[str, str]]]:
    """One list in the {weld, plain} shape checklist_for() takes: both kinds read the same list, so the department's
    weld flag no longer picks it."""
    return {"weld": items, "plain": items}


def stage_list(conn: Any, stage: Mapping[str, Any]) -> list[dict[str, str]]:
    """The checklist of one stage: the list frozen at START when set, else its department's live list."""
    frozen = _valid_list(stage.get("checklist_template"))
    if frozen is not None:
        return frozen
    return live_list(conn, str(stage["dept_code"]))


def stage_templates(conn: Any, stage_id: Any, dept_code: str) -> dict[str, list[dict[str, str]]]:
    """The checklist of a stage by id (the data book's stage records): frozen when set, else the department's live
    list. A record with no stage id reads the live list."""
    frozen = None
    if stage_id is not None:
        row = conn.execute("SELECT checklist_template FROM packet_stages WHERE id = %s", (stage_id,)).fetchone()
        frozen = row[0] if row else None
    return as_templates(stage_list(conn, {"dept_code": dept_code, "checklist_template": frozen}))


def templates_for_packet(
    conn: Any, dept_code: str, stages: Iterable[Mapping[str, Any]]
) -> dict[str, list[dict[str, str]]]:
    """The checklist the packet read, its completeness and the tick check use: the open stage's (frozen or live),
    else the last stage's when it is in the packet's department, else the department's live list."""
    stages = list(stages)
    stage = next((s for s in stages if s.get("closed_at") is None), None)
    if stage is None and stages and stages[-1].get("dept_code") == dept_code:
        stage = stages[-1]
    if stage is not None:
        return as_templates(stage_list(conn, stage))
    return as_templates(live_list(conn, dept_code))


def freeze_on_start(conn: Any, packet_id: int) -> None:
    """START: freeze the open stage's checklist, once. Later edits to the department's list do not reach it."""
    row = conn.execute(
        "SELECT id, dept_code FROM packet_stages WHERE packet_id = %s AND closed_at IS NULL"
        " AND checklist_template IS NULL",
        (packet_id,),
    ).fetchone()
    if row is None:
        return
    conn.execute(
        "UPDATE packet_stages SET checklist_template = %s WHERE id = %s AND checklist_template IS NULL",
        (Jsonb(live_list(conn, str(row[1]))), row[0]),
    )


def _fill(text: str, drawing: str | None, rev: str | None, wps: str | None) -> str:
    values = {"drawing": drawing or "", "rev": rev or NO_REV, "wps": wps or "per drawing"}
    return " ".join(RX_PLACEHOLDER.sub(lambda m: values[m.group(1)], text).split())


def checklist_for(
    weld: bool,
    drawing: str | None,
    rev: str | None,
    wps: str | None,
    templates: Mapping[str, list[dict[str, str]]] | None = None,
) -> list[dict[str, str]]:
    """The stage checklist for a department, as a flat list of {group, key, text} in display order."""
    t = templates or DEFAULT_TEMPLATES
    items = t.get("weld" if weld else "plain") or DEFAULT_TEMPLATES["weld" if weld else "plain"]
    return [_item(i["group"], i["key"], _fill(i["text"], drawing, rev, wps)) for i in items]


QC_SETTINGS_KEY = "qc_check_items"
RX_QC_PLACEHOLDER = re.compile(r"\{(drawing|rev|wps|stamp)\}")
G_BOOK, G_SPOOL = "Data book package", "Physical spool"

# The Q.C. check items, with {wps}, {stamp}, {drawing} and {rev} placeholders. The settings row `qc_check_items`
# (migration 0007) holds the same list; this is the fallback when that row is missing or does not parse.
QC_DEFAULT_ITEMS: list[dict[str, str]] = [
    _item(G_BOOK, "db_heats", "Heat number recorded for every BOM item"),
    _item(G_BOOK, "db_mtr", "MTRs on file and match the heat numbers"),
    _item(G_BOOK, "db_weldmap", "Weld map complete: every weld identified"),
    _item(G_BOOK, "db_wps", "Welds made to {wps}; welder {stamp}qualified"),
    _item(G_BOOK, "db_ck", "Stall checklist and weld record complete"),
    _item(G_SPOOL, "ph_dim", "Dimensions verified against {drawing} Rev {rev}"),
    _item(G_SPOOL, "ph_heat", "Heat numbers on material match the heat map"),
    _item(G_SPOOL, "ph_stamp", "Welds stamped with welder ID"),
    _item(G_SPOOL, "ph_clean", "Clean: no slag, spatter or arc strikes"),
    _item(G_SPOOL, "ph_qty", "Quantity matches the work orders"),
]


def parse_qc_items(value: Any) -> list[dict[str, str]] | None:
    """The `qc_check_items` settings value ({"groups": [{"group", "items": [{"key", "text"}]}]}) as a flat list of
    {group, key, text}. None when it is malformed."""
    if not isinstance(value, Mapping) or not isinstance(value.get("groups"), list):
        return None
    flat: list[dict[str, Any]] = []
    for g in value["groups"]:
        if not isinstance(g, Mapping) or not isinstance(g.get("items"), list):
            return None
        flat += [{**i, "group": g.get("group")} if isinstance(i, Mapping) else i for i in g["items"]]
    return _valid_list(flat)


def load_qc_items(conn: Any) -> list[dict[str, str]]:
    """The Q.C. check items from settings, else the defaults in code (with a warning when the row is bad)."""
    row = conn.execute("SELECT value FROM settings WHERE key = %s", (QC_SETTINGS_KEY,)).fetchone()
    if row is None:
        return QC_DEFAULT_ITEMS
    parsed = parse_qc_items(row[0])
    if parsed is None:
        log.warning("settings %s does not parse; using the default Q.C. items", QC_SETTINGS_KEY)
        return QC_DEFAULT_ITEMS
    return parsed


def qc_fill(text: str, drawing: str | None, rev: str | None, wps: str | None, welder_stamp: str | None) -> str:
    values = {
        "drawing": drawing or "the drawing",
        "rev": rev or NO_REV,
        "wps": wps or "the WPS",
        "stamp": f"[{welder_stamp}] " if welder_stamp else "",
    }
    return " ".join(RX_QC_PLACEHOLDER.sub(lambda m: values[m.group(1)], text).split())


def qc_items_for(
    drawing: str | None,
    rev: str | None,
    wps: str | None,
    welder_stamp: str | None,
    items: Iterable[Mapping[str, str]] | None = None,
) -> list[dict[str, str]]:
    """The Q.C. inspection items, as a flat list of {group, key, text} with the packet's values filled in."""
    src = list(items) if items is not None else QC_DEFAULT_ITEMS
    return [_item(i["group"], i["key"], qc_fill(i["text"], drawing, rev, wps, welder_stamp)) for i in src]


def checklist_keys(weld: bool, templates: Mapping[str, list[dict[str, str]]] | None = None) -> list[str]:
    return [i["key"] for i in checklist_for(weld, None, None, None, templates)]


def qc_keys(items: Iterable[Mapping[str, str]] | None = None) -> list[str]:
    return [i["key"] for i in (items if items is not None else QC_DEFAULT_ITEMS)]


def is_done(value: Any) -> bool:
    """A checklist or Q.C. check entry: `true`, or `{"done": true, ...}`."""
    if value is True:
        return True
    return isinstance(value, Mapping) and value.get("done") is True


def checklist_complete(
    checklist: Mapping[str, Any] | None, weld: bool, templates: Mapping[str, list[dict[str, str]]] | None = None
) -> bool:
    """Every key of the department checklist is done. An empty list counts as complete."""
    ck = checklist or {}
    return all(is_done(ck.get(k)) for k in checklist_keys(weld, templates))


def _plural(n: int, word: str) -> str:
    return f"{n} {word}{'s' if n > 1 else ''}"


def qc_missing(
    packet: Mapping[str, Any],
    qc: Mapping[str, Any] | None,
    welds: Iterable[Mapping[str, Any]],
    items: Iterable[Mapping[str, str]] | None = None,
) -> list[str]:
    """What Q.C. still has to record before an accept. The old qcMissing().

    `packet` is unused today (the item list does not depend on it for the keys) but kept for the old signature.
    `qc` is the open inspection row (checks, weld_exam, nde_method, nde_result, inspector) or None.
    `welds` are the live weld rows (weld_no). `items` are the loaded Q.C. items (load_qc_items); None means the
    defaults.
    """
    del packet
    q = qc or {}
    checks = q.get("checks") or {}
    missing: list[str] = []
    open_items = sum(1 for k in qc_keys(items) if not is_done(checks.get(k)))
    if open_items:
        missing.append(_plural(open_items, "inspection item"))
    exam = q.get("weld_exam") or {}
    results = []
    for w in welds:
        entry = exam.get(str(w.get("weld_no")))
        result = entry.get("result") if isinstance(entry, Mapping) else None
        results.append(str(result).lower() if result else "")
    no_result = sum(1 for r in results if not r)
    if no_result:
        missing.append(_plural(no_result, "weld") + " without a visual result")
    if any(r in REJECTS for r in results):
        missing.append("a rejected weld (reject the packet instead)")
    method = str(q.get("nde_method") or "").strip().lower()
    if method not in NDE_NONE and str(q.get("nde_result") or "").strip().lower() not in NDE_OK:
        missing.append("NDE result")
    if not str(q.get("inspector") or "").strip():
        missing.append("inspector name")
    return missing