"""Link inventory across all analysed repos -> analysis/data/links.tsv.

Statuses are the three the mandate fixes:

  ok                    target verified to exist
  broken                target verified to be absent
  points-outside-scope  target lies outside the analysed set

A fourth column, `kind`, carries the nuance the status alone cannot:
whether the target was a relative file, a git.lab issue, a repo URL, an
anchor, or an external URL.

Issue URLs resolve offline against gitlab_issues.json when that file
exists, so a rerun needs no network. Without it they are reported as
kind=issue-url, status=points-outside-scope, note=unresolved-no-issue-data.
"""

import json
import re
from urllib.parse import unquote, urlsplit

from common import (
    COMPONENTS, DATA_DIR, DOC_SUFFIXES, GROUP, OUT_OF_SCOPE_PROJECTS,
    OUT_OF_SCOPE_SUBGROUPS, repos, tracked_files, write_tsv,
)

# Inline markdown links, minus image embeds; reference definitions too.
LINK_RE = re.compile(r"(?<!\!)\[[^\]]*\]\(\s*<?([^)\s>]+)[^)]*\)")
# A reference definition needs a target that actually looks like one.
# Without that guard, log lines such as "[ERROR]: Task failed: ..." in
# imported wiki dumps parse as links to a file named "Task".
REFDEF_RE = re.compile(r"^\s{0,3}\[[^\]]+\]:\s*<?([^\s>]*[/.:#][^\s>]*)")

IN_SCOPE_REPOS = {slug for slug, _ in COMPONENTS} | {"management"}
ISSUE_URL_RE = re.compile(r"^/([^/]+(?:/[^/]+)*?)/-/issues/(\d+)")


def load_issue_index():
    """(project, iid) pairs known to exist, from a previous API export."""
    path = DATA_DIR / "gitlab_issues.json"
    if not path.exists():
        return None
    data = json.loads(path.read_text(encoding="utf-8"))
    return {(i["project"], i["iid"]) for i in data["issues"]}


def classify_url(target, issue_index):
    """-> (kind, status, note) for an absolute URL."""
    parts = urlsplit(target)
    host = parts.netloc.lower()
    if host != "git.lab":
        return ("external-url", "points-outside-scope", f"host={host}")

    m = ISSUE_URL_RE.match(parts.path)
    if m:
        ns, iid = m.group(1), int(m.group(2))
        group, _, project = ns.rpartition("/")
        if group != GROUP or project not in IN_SCOPE_REPOS:
            return ("issue-url", "points-outside-scope", f"project={ns}")
        if issue_index is None:
            return ("issue-url", "points-outside-scope", "unresolved-no-issue-data")
        if (project, iid) in issue_index:
            return ("issue-url", "ok", f"{project}#{iid}")
        return ("issue-url", "broken", f"{project}#{iid} not in group export")

    segs = [s for s in parts.path.split("/") if s]
    if segs and segs[0] == GROUP and len(segs) >= 2:
        project = segs[1]
        if project in OUT_OF_SCOPE_PROJECTS or project in OUT_OF_SCOPE_SUBGROUPS:
            return ("repo-url", "points-outside-scope", f"declared out of scope: {project}")
        if project in IN_SCOPE_REPOS:
            return ("repo-url", "ok", f"in-scope repo {project}")
    return ("repo-url", "points-outside-scope", f"path={parts.path or '/'}")


def classify_relative(repo_name, src, target, tracked):
    """-> (kind, status, note) for a repo-relative link."""
    path = unquote(target.split("#")[0].split("?")[0])
    if not path:
        return ("anchor", "ok", "same-document anchor")

    base = src.rsplit("/", 1)[0] if "/" in src else ""
    joined = f"{base}/{path}" if base and not path.startswith("/") else path.lstrip("/")

    resolved, stack = [], joined.split("/")
    for seg in stack:
        if seg in ("", "."):
            continue
        if seg == "..":
            if resolved:
                resolved.pop()
            else:
                return ("relative-file", "points-outside-scope",
                        "traverses above the repo root")
        else:
            resolved.append(seg)
    cand = "/".join(resolved)

    if cand in tracked:
        return ("relative-file", "ok", cand)
    # Directory links are legitimate targets in this doc set.
    if any(t.startswith(cand + "/") for t in tracked):
        return ("relative-file", "ok", cand + "/ (directory)")
    # Extensionless doc links ("[x](playwright#anchor)") are common in
    # imported upstream docs and resolve in the renderers that serve them.
    for suffix in sorted(DOC_SUFFIXES):
        if cand + suffix in tracked:
            return ("relative-file", "ok", f"{cand}{suffix} (extension implied)")
    return ("relative-file", "broken", f"no tracked file at {cand}")


def main():
    issue_index = load_issue_index()
    rows = []
    for name, repo in repos():
        tracked = set(tracked_files(name, repo))
        docs = [f for f in tracked if any(f.endswith(s) for s in DOC_SUFFIXES)]
        for src in docs:
            try:
                text = (repo / src).read_text(encoding="utf-8")
            except (OSError, UnicodeDecodeError):
                continue
            for lineno, line in enumerate(text.splitlines(), start=1):
                targets = LINK_RE.findall(line)
                ref = REFDEF_RE.match(line)
                if ref:
                    targets = targets + [ref.group(1)]
                for target in targets:
                    if target.startswith(("mailto:", "tel:")):
                        kind, status, note = ("mailto", "points-outside-scope", "")
                    elif target.startswith("#"):
                        kind, status, note = ("anchor", "ok", "same-document anchor")
                    elif re.match(r"^[a-zA-Z][a-zA-Z0-9+.-]*://", target):
                        kind, status, note = classify_url(target, issue_index)
                    else:
                        kind, status, note = classify_relative(name, src, target, tracked)
                    rows.append([name, src, lineno, kind, target, status, note])

    rows.sort(key=lambda r: (r[0], r[1], r[2], r[4]))
    write_tsv("links.tsv",
              ["repo", "src_path", "line", "kind", "target", "status", "note"],
              rows)


if __name__ == "__main__":
    main()