#!/usr/bin/env python3
"""
_gitea.py — transport. Everything that talks to Gitea, and nothing else.

Not a command. This module knows logins, HTTP verbs, pagination, and Gitea's
query quirks. It does NOT know what an issue is: no sections, no acceptance
criteria, no type taxonomy. Payload shapes come from map.py; the domain model
lives one layer further out in skills/issue/scripts/issue.py.

Login: resolved from .claude/settings.local.json (env.GITEA_LOGIN), walking up
from CWD — the same file /tea:auth writes and the tea-guard hook reads. No
script here accepts a login argument: the operator's pin is the only identity
they will use. No pin -> exit with a pointer to /tea:auth.

Also holds the id map (tmp/issues/.remote.json), which pairs a remote key with
a local slug, and the paths of the store-side files this layer writes. All of
it is transport bookkeeping, not domain data — the domain never reads any of
it, and losing the map still costs a re-pull and not information: the slug it
records also travels in the issue body as `<!-- tea:id … -->` (map.py), so a
pull rebuilds the entry from the tracker. See `rebuild_map`.

Request bodies go to tmp/payload/, which is this module's own scratchpad and
NOT a store: nothing in it is anybody's only copy, and writing one must never
materialize tmp/issues/ on a checkout that has none. Bootstrapping labels
touches no issue at all — it used to leave a store behind anyway, because the
request file had nowhere else to live. One directory, every caller, resolved
from this file the way the two domains resolve theirs.
"""
import datetime
import json
import os
import subprocess
import re
import sys
import urllib.parse

REMOTE_MAP = ".remote.json"

# --------------------------------------------------------------------------
# where request bodies land
# --------------------------------------------------------------------------
# Anchored on THIS FILE, like issue.store_root and page.store_root, so every
# caller — sync, wiki, whatever comes next — writes to one directory whatever
# it was invoked from. Visible and top-level under tmp/, not a dotdir hidden
# inside somebody's store, because a scratchpad that looks like store contents
# is how this went wrong the first time. `tmp/` is already gitignored.

PAYLOAD_PARTS = ("tmp", "payload")

# `.git` is a directory in a normal clone and a FILE in a worktree — hence
# exists(), not isdir(). AGENTS.md is the fallback for a plugin copied out of
# git; the agents-sync hook only ever puts one at a repository root.
REPO_MARKERS = (".git", "AGENTS.md")

_HERE = os.path.dirname(os.path.abspath(__file__))


def die(msg, code=1):
    sys.stderr.write("%s: %s\n" % (os.path.basename(sys.argv[0]), msg))
    sys.exit(code)


def warn(msg):
    sys.stderr.write("warning: %s\n" % msg)


def now_iso():
    return datetime.datetime.now(datetime.timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")


def repo_root(start):
    """Nearest ancestor of `start` (inclusive) carrying a repo marker, or None."""
    d = os.path.abspath(start)
    while True:
        if any(os.path.exists(os.path.join(d, m)) for m in REPO_MARKERS):
            return d
        parent = os.path.dirname(d)
        if parent == d:
            return None
        d = parent


def payload_root(start=None):
    """Absolute path of the request-body scratchpad.

    `start` overrides the anchor so the resolution can be exercised against a
    scratch tree. Outside a repository, cwd gets a turn, then the cwd-relative
    location stands — made absolute so an error can name the directory it
    really wrote to."""
    for anchor in ([start] if start is not None else [_HERE, os.getcwd()]):
        root = repo_root(anchor)
        if root:
            return os.path.join(root, *PAYLOAD_PARTS)
    return os.path.abspath(os.path.join(*PAYLOAD_PARTS))


PAYLOAD_ROOT = payload_root()


# --------------------------------------------------------------------------
# login
# --------------------------------------------------------------------------

def find_pin(start_dir=None):
    """Walk up from start_dir; return the login from the first
    .claude/settings.local.json carrying a non-empty env.GITEA_LOGIN."""
    d = os.path.abspath(start_dir or ".")
    while True:
        p = os.path.join(d, ".claude", "settings.local.json")
        if os.path.isfile(p):
            try:
                with open(p) as f:
                    v = (json.load(f).get("env") or {}).get("GITEA_LOGIN")
                if isinstance(v, str) and v.strip():
                    return v.strip()
            except Exception:
                pass
        parent = os.path.dirname(d)
        if parent == d:
            return None
        d = parent


def require_login():
    login = find_pin(os.getcwd())
    if not login:
        die("no login pinned (.claude/settings.local.json env.GITEA_LOGIN). Run /tea:auth.")
    return login


# --------------------------------------------------------------------------
# api
# --------------------------------------------------------------------------

def api(login, endpoint, method="GET", payload=None, payload_name=None,
        allow_fail=False):
    """Call `tea api`; return parsed JSON (None on an empty body).

    payload (a dict) is written to PAYLOAD_ROOT/<name>.json and passed as
    -d @file — the file survives the call for retries and debugging. Where
    that is, is not the caller's business and never was: the directory is
    this layer's scratchpad, and the one time it was a caller's decision it
    got pointed at the issue store. allow_fail returns None instead of
    exiting when the call fails."""
    cmd = ["tea", "api", "--login", login]
    if method != "GET":
        cmd += ["-X", method]
    if payload is not None:
        os.makedirs(PAYLOAD_ROOT, exist_ok=True)
        path = os.path.join(PAYLOAD_ROOT, "%s.json" % (payload_name or "request"))
        with open(path, "w") as f:
            json.dump(payload, f, ensure_ascii=False, indent=2)
        cmd += ["-d", "@" + path]
    cmd.append(endpoint)

    r = subprocess.run(cmd, capture_output=True, text=True)
    if r.returncode != 0:
        if allow_fail:
            return None
        die("`tea api %s %s` failed:\n%s" % (method, endpoint, (r.stderr or r.stdout).strip()))
    body = r.stdout.strip()
    if not body:
        return None
    try:
        return json.loads(body)
    except json.JSONDecodeError:
        if allow_fail:
            return None
        die("`tea api %s` returned non-JSON:\n%s" % (endpoint, body[:500]))


def paginate(login, endpoint, limit=50, max_pages=40, **kw):
    """GET a list endpoint page by page; return the concatenated list."""
    sep = "&" if "?" in endpoint else "?"
    out = []
    for page in range(1, max_pages + 1):
        batch = api(login, "%s%spage=%d&limit=%d" % (endpoint, sep, page, limit), **kw)
        if not isinstance(batch, list) or not batch:
            break
        out.extend(batch)
        if len(batch) < limit:
            break
    return out


def repo_base(repo=None):
    """API prefix. Without --repo, let tea fill {owner}/{repo} from CWD."""
    return "repos/%s" % repo if repo else "repos/{owner}/{repo}"


def repo_slug(login, repo=None):
    """owner/repo as a literal string — needed for remote keys, which must not
    contain tea's {owner}/{repo} placeholder."""
    if repo:
        return repo
    got = api(login, "repos/{owner}/{repo}", allow_fail=True)
    if isinstance(got, dict) and got.get("full_name"):
        return got["full_name"]
    die("cannot determine owner/repo from the CWD — pass --repo owner/repo")


def parse_key(key):
    """Return (number, repo-or-None) from 42 / #42 / owner/repo#42 / a URL."""
    key = key.strip()
    m = re.match(r'^https?://[^/]+/([^/]+)/([^/]+)/issues/(\d+)/?$', key)
    if m:
        return int(m.group(3)), "%s/%s" % (m.group(1), m.group(2))
    m = re.match(r'^([\w.-]+/[\w.-]+)#(\d+)$', key)
    if m:
        return int(m.group(2)), m.group(1)
    m = re.match(r'^#?(\d+)$', key)
    if m:
        return int(m.group(1)), None
    die("cannot parse issue key %r (want 42, #42, owner/repo#42, or an issue URL)" % key)


# --------------------------------------------------------------------------
# filters
# --------------------------------------------------------------------------

def resolve_milestone(login, base, value):
    """(id, title) for a milestone given by id or title. Exits if unknown.

    Gitea silently IGNORES an unresolvable `milestones=` filter and returns the
    whole backlog, so the milestone must be resolved before it is trusted."""
    got = paginate(login, "%s/milestones?state=all" % base, limit=100)
    for m in got or []:
        if str(m.get("id")) == str(value) or m.get("title") == str(value):
            return m["id"], m.get("title", "")
    have = ", ".join("%s (id %d)" % (m.get("title", ""), m["id"]) for m in got or [])
    die("no milestone %r in this repo — have: %s" % (value, have or "none"))


def matches(payload, milestone_id=None, labels=()):
    """Client-side re-check of a server-side filter — see resolve_milestone."""
    if payload.get("pull_request"):
        return False
    if milestone_id is not None and (payload.get("milestone") or {}).get("id") != milestone_id:
        return False
    names = {l.get("name", "") for l in payload.get("labels") or []}
    return all(l in names for l in labels)


def list_issues(login, base, state="open", labels=(), query=None,
                milestone=None, limit=100):
    """Filtered issue payloads. Returns (payloads, milestone_title).

    One request per page, and the payload already carries the issue bodies — a
    whole milestone costs one call per 50 issues, not one per issue."""
    ms_id, ms_title = (None, None)
    if milestone is not None:
        ms_id, ms_title = resolve_milestone(login, base, milestone)

    params = {"state": state, "type": "issues"}
    if labels:
        params["labels"] = ",".join(labels)
    if query:
        params["q"] = query
    if ms_title:
        params["milestones"] = ms_title
    endpoint = "%s/issues?%s" % (base, urllib.parse.urlencode(params))

    per_page = min(limit, 50)
    got = paginate(login, endpoint, limit=per_page,
                   max_pages=max(1, -(-limit // per_page)))
    got = [p for p in got if matches(p, ms_id, labels)]
    return got[:limit], ms_title


def get_issue(login, base, number):
    payload = api(login, "%s/issues/%d" % (base, number))
    if not isinstance(payload, dict) or "number" not in payload:
        die("issue #%d not found" % number)
    return payload


def get_comments(login, base, number):
    return paginate(login, "%s/issues/%d/comments" % (base, number))


def native_deps(login, base, number):
    """Gitea's own issue-dependency links; empty when unsupported."""
    got = api(login, "%s/issues/%d/dependencies" % (base, number), allow_fail=True)
    return [i["number"] for i in got] if isinstance(got, list) else []


def native_dep_pairs(login, base, number):
    """The same links as {(owner/repo, number)} — what a repeat push compares
    against so it does not POST a link the tracker already has.

    A bare number is ambiguous the moment a dependency lives in another repo,
    and IssueMeta lets it, so the repo travels with it. The pair is a transport
    fact; formatting it as `owner/repo#42` is map.py's job, not this module's."""
    got = api(login, "%s/issues/%d/dependencies" % (base, number), allow_fail=True)
    out = set()
    for i in got if isinstance(got, list) else []:
        repo = (i.get("repository") or {}).get("full_name") or ""
        if "number" in i:
            out.add((repo, int(i["number"])))
    return out


def add_dependency(login, base, number, dep_repo, dep_number):
    """Make issue `number` depend on `dep_repo#dep_number`. True on success.

    Confirmed against the instance's own swagger.v1.json (Gitea 1.26.1):

        POST /repos/{owner}/{repo}/issues/{index}/dependencies
        body: IssueMeta — {"index": <int>, "owner": "<owner>", "repo": "<name>"}
        "Make the issue in the url depend on the issue in the form."

    The URL names the blocked issue and the body the blocker, which is the same
    direction native_deps reads back ("all issues that block this issue"). A
    link that already exists answers 409, so a failure here is reported and not
    fatal: one missing cross-link must not abort a push that has already
    created issues. Callers pre-filter with native_dep_pairs."""
    owner, _, name = (dep_repo or "").partition("/")
    if not owner or not name:
        return False
    payload = {"index": int(dep_number), "owner": owner, "repo": name}
    got = api(login, "%s/issues/%d/dependencies" % (base, number), "POST", payload,
              payload_name="dep-%d-%d" % (number, dep_number), allow_fail=True)
    return got is not None


# --------------------------------------------------------------------------
# labels
# --------------------------------------------------------------------------

def ensure_labels(login, base, specs, root):
    """Map label name -> id, creating what the repo is missing.

    `specs` is {name: {"color", "description", "exclusive"}} handed in by the
    caller — this module does not know which namespaces are exclusive or what
    they mean. Cached in <root>/.labels.json; the cache is refreshed from the
    API before anything is created."""
    cache_path = os.path.join(root, ".labels.json")
    cache = {}
    if os.path.isfile(cache_path):
        try:
            with open(cache_path) as f:
                cache = json.load(f)
        except Exception:
            cache = {}

    if any(n not in cache for n in specs):
        cache = {l["name"]: l["id"] for l in paginate(login, "%s/labels" % base, limit=100)}

    for name, spec in specs.items():
        if name in cache:
            continue
        payload = dict(spec, name=name)
        created = api(login, "%s/labels" % base, "POST", payload,
                      payload_name="label-%s" % name.replace("/", "-"))
        if not created or "id" not in created:
            die("could not create label %r" % name)
        cache[name] = created["id"]
        sys.stderr.write("created label %s%s\n"
                         % (name, " (exclusive)" if spec.get("exclusive") else ""))

    os.makedirs(root, exist_ok=True)
    with open(cache_path, "w") as f:
        json.dump(cache, f, indent=2, sort_keys=True)
    return {n: cache[n] for n in specs}


def resolve_milestone_id(login, base, title):
    """Milestone id for a title, or None when the repo has no such milestone."""
    if not title or title == "none":
        return None
    for m in paginate(login, "%s/milestones?state=all" % base, limit=100) or []:
        if m.get("title") == title:
            return m["id"]
    return None


# --------------------------------------------------------------------------
# store-side files this layer owns
# --------------------------------------------------------------------------
# The issue file itself is the domain's (`issue.path_of`). The one file the sync
# layer puts beside it is named here, in one place, because three commands have
# to agree on it: pull.py writes the thread, comment.py refetches it, push.py
# deletes it along with the issue it just sent.

def comments_path(root, id):
    """An issue's comment thread — beside it, under the same slug.

    A path, not a concept the domain needs: a thread is pulled from Gitea and
    never pushed back, so the domain has no reason to know the file exists."""
    return os.path.join(root, "%s.comments.md" % id)


# --------------------------------------------------------------------------
# id map: remote key <-> local slug
# --------------------------------------------------------------------------

def map_path(root):
    return os.path.join(root, REMOTE_MAP)


def load_map(root):
    """{"owner/repo#42": "wire-sqlc-appclick"} — the local slug ledger.

    Entries outlive the files they name, and that is now the normal case rather
    than a leak: `push.py` deletes an issue's file the moment Gitea confirms it,
    and the entry it leaves behind is what lets the next `pull.py 42` land on
    the same slug. Nothing prunes them, because "no file" no longer means "no
    such issue". A stale entry costs one json line and is corrected the next
    time that number is pulled."""
    p = map_path(root)
    if not os.path.isfile(p):
        return {}
    try:
        with open(p) as f:
            got = json.load(f)
        return got if isinstance(got, dict) else {}
    except Exception:
        return {}


def save_map(root, m):
    os.makedirs(root, exist_ok=True)
    with open(map_path(root), "w") as f:
        json.dump(m, f, indent=2, sort_keys=True)


def rebuild_map(root, issues):
    """Fold the `gitea:` fields still on disk into the id map. Returns it.

    This used to say "the files are the source of truth; .remote.json is only an
    index over them", and that stopped being true the day push started deleting
    the file it had just sent. A pushed issue leaves no `gitea:` field behind to
    read, so the files are now a SUBSET of what the map knows, and a rebuild
    from them alone would throw away every entry it cannot see.

    So the contradiction is resolved by moving the source of truth, not by
    keeping this function honest about files:

        Gitea            the issue, and — in `<!-- tea:id … -->` — its slug
        .remote.json     a local number -> slug ledger, a cache of that marker
        tmp/issues/*.md  whatever happens to be checked out right now

    Which makes this a MERGE and never a replacement: it starts from what is
    already recorded and adds what the remaining files say. What it cannot
    recover — a pushed-and-dropped issue whose ledger entry was also lost — is
    not lost either; the next `pull.py <n>` reads the slug off the marker and
    writes the entry back."""
    m = load_map(root)
    for id, iss in issues.items():
        key = iss.extra.get("gitea")
        if key:
            m[key] = id
    save_map(root, m)
    return m