#!/usr/bin/env python3
"""Rebuild the bundled TSL API index from the codegen markdown tree.

The markdown tree is the source of truth. The TSV is a derived product;
regenerate it whenever the leaf Markdown changes rather than editing it by
hand.

Columns (tab-separated, LF line endings, UTF-8):
    name  scope  module  signature  page  anchor  tags  summary
    kind  binding  visibility  owner  qualified_name
- name:      signature text up to the first '('
- scope:     first path segment under the codegen root (for example project)
- module:    second path segment for nested pages, else the flat file stem
- signature: verbatim from the heading, backticks stripped
- page:      POSIX path relative to the codegen root
- anchor:    top-level declarations use the historic name slug; typed members
             slug the complete visible API title. Per-page duplicate slugs get
             -1/-2 suffixes in document order.
- tags:      space-separated keywords from `<!-- tags: ... -->`
- summary:   first prose line under the entry heading
- kind:      function/class/method/property/field/constant/unit/variable
- binding:   instance/class/static/unit, or empty when not applicable
- visibility: public/protected for class members; public for unit interface
- owner:     dot-separated containing API path, excluding the entry name
- qualified_name: dot-separated stable API identity

Usage (run from repo root; --skill-dir is required):
    SKILL=skills/tsl-api-reference
    python tools/tsl-codegen/scripts/build_index.py \
        --skill-dir "$SKILL"            # rewrite the TSV in place
    python tools/tsl-codegen/scripts/build_index.py \
        --skill-dir "$SKILL" --check    # verify against md tree, no write
"""
import argparse
import sys
from pathlib import Path
import re

SCRIPT_DIR = Path(__file__).resolve().parent
if str(SCRIPT_DIR) not in sys.path:
    sys.path.insert(0, str(SCRIPT_DIR))

from api_markdown import DECLARATION_LINE_RE, iter_api_entries, slug


RETURN_RE = re.compile(r"^返回[:：]")
DECLARATION_TYPE_RE = re.compile(
    r"^类型[:：]\s*(function|class|unit)\s*$", re.IGNORECASE
)
TAGS_RE = re.compile(r"^<!--\s*tags:\s*(.*?)\s*-->$")
VISIBILITY_RE = re.compile(
    r"^可见性[:：]\s*`?(public|protected|private)`?\s*$",
    re.IGNORECASE,
)
HEADER = [
    "name",
    "scope",
    "module",
    "signature",
    "page",
    "anchor",
    "tags",
    "summary",
    "kind",
    "binding",
    "visibility",
    "owner",
    "qualified_name",
]


def extract_metadata(lines, heading_idx, end_idx=None):
    """Return tags and the first prose line under one API heading."""
    tags = ""
    summary = ""
    summary_open = True
    for line in lines[heading_idx + 1:end_idx]:
        text = line.strip()
        if not text:
            continue
        if DECLARATION_LINE_RE.fullmatch(text):
            continue
        tag_match = TAGS_RE.match(text)
        if tag_match:
            tags = " ".join(tag_match.group(1).split()).replace("\t", " ")
            continue
        if summary:
            continue
        if (
            text.startswith("|")
            or text.startswith("#")
            or RETURN_RE.match(text)
            or DECLARATION_TYPE_RE.match(text)
        ):
            summary_open = False
            continue
        if summary_open:
            summary = text.replace("\t", " ")
    return tags, summary


def extract_visibility(lines, start, end):
    for line in lines[start + 1:end]:
        match = VISIBILITY_RE.match(line.strip())
        if match:
            return match.group(1).casefold()
    return ""


def next_anchor(base, seen):
    count = seen.get(base, 0)
    seen[base] = count + 1
    return base if count == 0 else f"{base}-{count}"


def parse_page(codegen_root, md):
    """Yield index rows for one Markdown page."""
    page = md.relative_to(codegen_root).as_posix()
    scope, module = scope_module(page)
    seen = {}
    rows = []
    lines = md.read_text(encoding="utf-8").splitlines()
    entries = list(iter_api_entries(lines))
    root_kind = ""
    root_name = ""
    unit_class_owner = ""

    for entry in entries:
        heading = entry.heading
        if not heading.valid:
            continue

        if heading.level == 2:
            root_kind = heading.kind
            root_name = heading.name
            unit_class_owner = ""
            owner = ""
            anchor_base = slug(heading.name)
        elif root_kind == "class":
            owner = root_name
            anchor_base = slug(heading.visible_title)
        elif root_kind == "unit" and heading.level == 3:
            anchor_base = slug(heading.visible_title)
            owner = root_name
            unit_class_owner = (
                f"{root_name}.{heading.name}"
                if heading.kind == "class"
                else ""
            )
        elif root_kind == "unit" and heading.level == 4:
            owner = unit_class_owner
            anchor_base = slug(heading.visible_title)
        else:
            continue

        qualified_name = (
            f"{owner}.{heading.name}" if owner else heading.name
        )
        if root_kind == "unit" and heading.level == 3:
            visibility = "public"
        elif (
            root_kind == "class" and heading.level == 3
        ) or (root_kind == "unit" and heading.level == 4):
            visibility = extract_visibility(lines, entry.start, entry.end)
        else:
            visibility = ""

        tags, summary = extract_metadata(lines, entry.start, entry.end)
        rows.append(
            [
                heading.name,
                scope,
                module,
                heading.signature,
                page,
                next_anchor(anchor_base, seen),
                tags,
                summary,
                heading.kind,
                heading.binding,
                visibility,
                owner,
                qualified_name,
            ]
        )
    return rows


def scope_module(page):
    parts = page.split("/")
    scope = parts[0]
    module = parts[1] if len(parts) >= 3 else Path(parts[-1]).stem
    return scope, module


def build_rows(codegen_root):
    """Scan the whole codegen tree and return sorted rows."""
    rows = []
    for md in sorted(codegen_root.rglob("*.md")):
        rows.extend(parse_page(codegen_root, md))
    rows.sort(key=lambda r: (r[0].lower(), r[4], r[3]))
    return rows


def render_tsv(rows):
    lines = ["\t".join(HEADER)]
    lines.extend("\t".join(r) for r in rows)
    return "\n".join(lines) + "\n"


def read_tsv(tsv_path):
    text = tsv_path.read_text(encoding="utf-8")
    return [line.split("\t") for line in text.splitlines() if line.strip()]


def main(argv=None):
    if hasattr(sys.stdout, "reconfigure"):
        sys.stdout.reconfigure(encoding="utf-8")
    parser = argparse.ArgumentParser(
        description=__doc__.splitlines()[0],
        add_help=False,
        allow_abbrev=False,
    )
    parser.add_argument(
        "--help",
        action="help",
        help="show this help message and exit (no -h short option)",
    )
    parser.add_argument(
        "--skill-dir",
        required=True,
        help="tsl-api-reference skill dir; codegen root defaults to "
        "<skill-dir>/references/codegen and tsv to "
        "<skill-dir>/data/function_index.tsv",
    )
    parser.add_argument(
        "--root",
        help="explicit codegen root, overriding the one derived from --skill-dir",
    )
    parser.add_argument(
        "--tsv",
        help="explicit output tsv, overriding the one derived from --skill-dir",
    )
    parser.add_argument(
        "--check",
        action="store_true",
        help="verify the tsv matches the md tree; exit 1 if not (no write)",
    )
    args = parser.parse_args(argv)

    skill_root = Path(args.skill_dir)
    codegen_root = (
        Path(args.root) if args.root else skill_root / "references" / "codegen"
    )
    if not codegen_root.is_dir():
        print(f"ERROR: codegen root not found: {codegen_root}", file=sys.stderr)
        return 1
    tsv_path = (
        Path(args.tsv)
        if args.tsv
        else skill_root / "data" / "function_index.tsv"
    )

    rows = build_rows(codegen_root)
    new_text = render_tsv(rows)

    if args.check:
        if not tsv_path.is_file():
            print(f"MISMATCH: tsv does not exist: {tsv_path}", file=sys.stderr)
            return 1
        current = tsv_path.read_text(encoding="utf-8")
        tsv_ok = current == new_text
        if tsv_ok:
            print(f"OK: {tsv_path} matches md tree ({len(rows)} rows)")
            return 0
        if not tsv_ok:
            cur_rows = read_tsv(tsv_path)[1:]
            cur_keys = {tuple(r) for r in cur_rows}
            new_keys = {tuple(r) for r in rows}
            print(
                f"MISMATCH: tsv out of date "
                f"(tsv {len(cur_rows)} rows, md {len(rows)} rows; "
                f"+{len(new_keys - cur_keys)} -{len(cur_keys - new_keys)}). "
                f"Run without --check to rebuild.",
                file=sys.stderr,
            )
        return 1

    tsv_path.parent.mkdir(parents=True, exist_ok=True)
    tsv_path.write_text(new_text, encoding="utf-8", newline="\n")
    print(f"wrote {tsv_path}: {len(rows)} rows")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())