"""The target set of targeted F3: the nodes a team's claims, data and quotations rest on.

Non-normative; see spec/08-fidelity.md §8.10.
"""

from .model import LEAVES, MATH_KINDS
from .text import is_digit

DIGIT_RULES = ("all", "anchored-sections", "none")
# The kinds that count as the section a node sits in: a section, or the front or back matter outside any.
SECTION_KINDS = frozenset(["section", "front", "back"])
DIGIT_KINDS = frozenset(["sentence", "cell"])
DIGIT_RUNS = frozenset(["text", "math"])


def has_digit_run(node):
    """Whether a `text` or `math` run of the node holds a digit (General Category Nd)."""
    for r in node.get("content") or []:
        if not isinstance(r, dict) or r.get("kind") not in DIGIT_RUNS:
            continue
        s = r.get("text") if r["kind"] == "text" else r.get("source")
        if any(is_digit(ch) for ch in s or ""):
            return True
    return False


def enclosing_section(doc, nid):
    """The nearest ancestor-or-self that is a section, or the front or back matter, else the root."""
    if doc.nodes[nid]["kind"] in SECTION_KINDS:
        return nid
    for a in reversed(doc.ancestors(nid)):
        if doc.nodes[a]["kind"] in SECTION_KINDS:
            return a
    return doc.root


def target_set(doc, anchored, digit_rule="all"):
    """The target set as `[[node, reason], …]` in document order, with `reason` the first that applies of
    `anchored`, `equation` and `digits`.

    `anchored` lists the live nodes that extracts, dataset values, confirmed claim links, draft quotations or
    pinned citations anchor; a container among them contributes its leaves. Every equation and equation line
    is a target. Under `all`, so is every sentence or cell with a digit in a text or math run; under
    `anchored-sections`, only those in a section that holds an anchored node; under `none`, none.
    """
    if digit_rule not in DIGIT_RULES:
        raise ValueError("digit rule must be one of %s" % ", ".join(DIGIT_RULES))
    anchored = set(anchored)
    unknown = sorted(a for a in anchored if a not in doc.nodes)
    if unknown:
        raise ValueError("anchored nodes are not live: %s" % ", ".join(unknown))
    reasons = {}
    for nid in sorted(anchored):
        if doc.nodes[nid]["kind"] in LEAVES:
            reasons[nid] = "anchored"
        else:
            for leaf in doc.leaves(nid):
                reasons.setdefault(leaf, "anchored")
    for nid in doc.preorder():
        if doc.nodes[nid]["kind"] in MATH_KINDS:
            reasons.setdefault(nid, "equation")
    if digit_rule != "none":
        sections = {enclosing_section(doc, a) for a in anchored}
        for nid in doc.preorder():
            n = doc.nodes[nid]
            if n["kind"] in DIGIT_KINDS and has_digit_run(n):
                if digit_rule == "all" or enclosing_section(doc, nid) in sections:
                    reasons.setdefault(nid, "digits")
    return [[nid, reasons[nid]] for nid in doc.preorder() if nid in reasons]