"""Bridge: procedure_parser -> BrSeq/BrIf/BrEval tree pipeline integration.

Primary: new procedure_parser (fast, deterministic, no path explosion).
Fallback: old BrParser (timeout-guarded for programs new parser can't handle).
"""

from .models import BrSeq, BrIf, BrEval, BrPerform, BrSearch, GoTo
from .procedure_parser import extract_branch_tree as new_parse, BranchNode


def build_branch_tree_fallback(proc_text, fields=None):
    """New parser primary with old parser timeout fallback."""
    from .core import build_branch_tree as old_build

    # 1. New parser (fast, 10-50ms, no DP cap limit)
    new_tree, new_assigns = None, {}
    try:
        root, assigns_list = new_parse(proc_text, fields)
        new_tree = _convert_to_model(root)
        new_assigns = _assigns_list_to_dict(assigns_list)
    except Exception:
        pass

    # New parser generates O(N) paths (not O(2^N)), so no cap needed.
    # Just use it directly when it works.
    if new_tree is not None:
        return new_tree, new_assigns

    # 2. Old parser with 3s timeout (fallback only)
    old_tree, old_assigns = None, {}
    try:
        import threading
        r, e, d = [None], [None], [False]
        def run():
            try:
                r[0] = old_build(proc_text, fields)
            except Exception as ex:
                e[0] = ex
            d[0] = True
        t = threading.Thread(target=run, daemon=True)
        t.start(); t.join(3.0)
        if d[0] and not e[0] and r[0]:
            ot, oa = r[0]
            old_tree, old_assigns = ot, oa
    except Exception:
        pass

    if old_tree is not None:
        return old_tree, old_assigns
    return BrSeq(), {}


def _convert_to_model(root: BranchNode) -> BrSeq:
    seq = BrSeq()
    for c in root.children:
        _convert_node(c, seq)
    return seq


def _convert_node(node: BranchNode, parent: BrSeq):
    k = node.kind

    if k in ("PARAGRAPH", "SECTION", "PERFORM_CALL", "GO_TO", "EXIT", "CALL"):
        for c in node.children:
            _convert_node(c, parent)
        return

    if k == "IF":
        br = BrIf(node.condition_text or " ".join(node.branch_names))
        for c in node.children:
            if c.kind == "ELSE":
                for ec in c.children: _convert_node(ec, br.false_seq)
            elif c.kind == "THEN":
                for sc in c.children: _convert_node(sc, br.true_seq)
            else:
                _convert_node(c, br.true_seq)
        parent.add(br)
        return

    if k == "EVALUATE":
        subj = (node.branch_names or [""])[0]
        subj = subj[5:-1] if subj.startswith("EVAL(") and subj.endswith(")") else subj
        br = BrEval(subj)
        for c in node.children:
            if c.kind == "WHEN":
                cond = (c.branch_names or [""])[0]
                cond = cond[5:-1] if cond.startswith("WHEN(") and cond.endswith(")") else cond
                # Strip trailing body text (everything after first COBOL verb)
                cond = cond.split()[0] if cond.split() else cond
                ws = BrSeq()
                for wc in c.children: _convert_node(wc, ws)
                if cond.upper() == "OTHER":
                    br.has_other = True
                    for wc in c.children: _convert_node(wc, br.other_seq)
                else:
                    br.when_list.append((cond, ws))
        parent.add(br)
        return

    if k == "PERFORM":
        cond = node.condition_text or ""
        u = cond.upper()
        if 'VARYING' in u:
            br = BrPerform("varying", condition=cond)
        elif 'UNTIL' in u:
            br = BrPerform("until", condition=cond)
        else:
            br = BrPerform("times", condition=cond)
        for c in node.children: _convert_node(c, br.body_seq)
        parent.add(br)
        return

    if k == "READ":
        for c in node.children: _convert_node(c, parent)
        return

    if k == "AT_END":
        br = BrIf("AT END")
        for c in node.children: _convert_node(c, br.true_seq)
        parent.add(br)
        return

    if k == "NOT_AT_END":
        for i in range(len(parent.children) - 1, -1, -1):
            if isinstance(parent.children[i], BrIf):
                for c in node.children:
                    _convert_node(c, parent.children[i].false_seq)
                break
        return

    if k in ("SORT", "MERGE", "WHEN"):
        name = " ".join(node.branch_names) if node.branch_names else k
        parent.add(BrPerform("sort", condition=name))
        return

    if k == "GO_TO_DEPENDING":
        parent.add(GoTo("DEPENDING"))
        return

    for c in node.children:
        _convert_node(c, parent)


def _count_br_nodes(node) -> int:
    count = 0
    if isinstance(node, (BrIf, BrEval, BrPerform, BrSearch)):
        count += 1
    if isinstance(node, BrSeq):
        for c in node.children: count += _count_br_nodes(c)
    if isinstance(node, BrIf):
        count += _count_br_nodes(node.true_seq) + _count_br_nodes(node.false_seq)
    if isinstance(node, BrEval):
        for _, s in node.when_list: count += _count_br_nodes(s)
        count += _count_br_nodes(node.other_seq)
    if isinstance(node, BrPerform):
        count += _count_br_nodes(node.body_seq)
    if isinstance(node, BrSearch):
        count += _count_br_nodes(node.at_end_seq)
        for _, s in node.when_list: count += _count_br_nodes(s)
    return count


def _assigns_list_to_dict(assigns_list: list) -> dict:
    result = {}
    for a in assigns_list:
        tgt = a.get("tgt", "")
        src = a.get("src") or a.get("source_vars")
        if tgt and src:
            result[tgt] = [a]
    return result