"""Activity feed API — serves contribution events from pipeline.db."""
import re
import sqlite3
import math
import time
from aiohttp import web

DB_PATH = "/opt/teleo-eval/pipeline/pipeline.db"
_cache = {"data": None, "ts": 0}
CACHE_TTL = 60  # 1 minute — activity should feel fresh

# commit_types we surface in the activity feed. `pipeline` is system
# maintenance (reweave/fix auto-runs, zombie cleanup) and stays hidden.
_FEED_COMMIT_TYPES = ("knowledge", "enrich", "challenge", "research", "entity", "extract", "reweave")

# Source-archive slugs follow YYYY-MM-DD-publisher-topic-HASH4 — they're
# inbox archive filenames, not claim slugs. Used as a fallback signal when
# branch/description heuristics miss (e.g. populated descriptions that
# happen to be source titles, not claim insights).
_SOURCE_SLUG_PATTERN = re.compile(r"^\d{4}-\d{2}-\d{2}-.+-[a-f0-9]{4}$")


def _get_conn():
    conn = sqlite3.connect(DB_PATH)
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA busy_timeout = 10000")
    return conn


def _is_source_slug(slug):
    return bool(slug and _SOURCE_SLUG_PATTERN.match(slug))


def _classify_event(branch, description, commit_type, candidate_slug=None):
    """Return one of: create | enrich | challenge | source | None.

    Source-archive PRs are extract/* branches that filed a source into
    inbox/archive/ but didn't produce a claim. Two signals classify them
    as 'source' (defense in depth):
      1. extract/* branch with empty description (no claim title produced)
      2. candidate_slug matches YYYY-MM-DD-...-HASH4 (inbox filename pattern)
    """
    commit_type_l = (commit_type or "").lower()
    branch = branch or ""
    description_lower = (description or "").lower()
    has_desc = bool(description and description.strip())

    if commit_type_l not in _FEED_COMMIT_TYPES:
        return None

    # Explicit challenge signals win first.
    if (commit_type_l == "challenge"
            or branch.startswith("challenge/")
            or "challenged_by" in description_lower):
        return "challenge"

    # Enrichment: reweave edge-connects, enrich/ branches, or commit_type=enrich.
    if (commit_type_l == "enrich"
            or branch.startswith("enrich/")
            or branch.startswith("reweave/")):
        return "enrich"

    # Source-only: extract/* with no claim description means inbox archive
    # landed but no domain claim was written.
    if branch.startswith("extract/") and not has_desc:
        return "source"

    # Belt-and-suspenders: if the slug we'd surface to the frontend looks
    # like an inbox archive filename (date-prefix-hash), treat as source
    # regardless of branch/commit_type/description state. Catches cases
    # where description leaked but is just a source title, not a claim.
    if _is_source_slug(candidate_slug):
        return "source"

    # Everything else with a description is a new claim.
    return "create"


def _normalize_contributor(submitted_by, agent):
    if submitted_by and submitted_by.strip():
        name = submitted_by.strip().lstrip("@")
        return name
    if agent and agent.strip() and agent != "pipeline":
        return agent.strip()
    return "pipeline"


def _summary_from_branch(branch):
    if not branch:
        return ""
    parts = branch.split("/", 1)
    if len(parts) < 2:
        return ""
    slug = parts[1]
    slug = re.sub(r"^[\d-]+-", "", slug)  # strip date prefix
    slug = re.sub(r"-[a-f0-9]{4}$", "", slug)  # strip hash suffix
    return slug.replace("-", " ").strip().capitalize()


def _extract_claim_slugs(description, branch=None):
    if not description:
        if branch:
            parts = branch.split("/", 1)
            if len(parts) > 1:
                return [parts[1][:120]]
        return []
    titles = [t.strip() for t in description.split("|") if t.strip()]
    slugs = []
    for title in titles:
        slug = title.lower().strip()
        slug = "".join(c if c.isalnum() or c in (" ", "-") else "" for c in slug)
        slug = slug.replace(" ", "-").strip("-")
        if len(slug) > 10:
            slugs.append(slug[:120])
    return slugs


def _hot_score(challenge_count, enrich_count, signal_count, hours_since):
    numerator = challenge_count * 3 + enrich_count * 2 + signal_count
    denominator = max(hours_since, 0.5) ** 1.5
    return numerator / denominator


def _build_events():
    conn = _get_conn()
    try:
        placeholders = ",".join("?" * len(_FEED_COMMIT_TYPES))
        rows = conn.execute(f"""
            SELECT p.number, p.branch, p.domain, p.agent, p.submitted_by,
                   p.merged_at, p.description, p.commit_type, p.cost_usd,
                   p.source_channel, p.source_path
            FROM prs p
            WHERE p.status = 'merged'
              AND p.commit_type IN ({placeholders})
              AND p.merged_at IS NOT NULL
            ORDER BY p.merged_at DESC
            LIMIT 2000
        """, _FEED_COMMIT_TYPES).fetchall()

        events = []
        claim_activity = {}  # slug -> {challenges, enriches, signals, first_seen}

        for row in rows:
            slugs = _extract_claim_slugs(row["description"], row["branch"])
            candidate_slug = slugs[0] if slugs else ""
            event_type = _classify_event(
                row["branch"], row["description"], row["commit_type"],
                candidate_slug=candidate_slug,
            )
            if not event_type:
                continue

            contributor = _normalize_contributor(row["submitted_by"], row["agent"])
            merged_at = row["merged_at"] or ""

            ci_map = {"create": 0.35, "enrich": 0.25, "challenge": 0.40, "source": 0.15}
            ci_earned = ci_map.get(event_type, 0)

            # Source events never carry a claim_slug — no claim was written —
            # so the frontend can't produce a 404-ing claim link.
            if event_type == "source":
                summary_text = _summary_from_branch(row["branch"])
                source_slug = (
                    _summary_from_branch(row["branch"]).lower().replace(" ", "-")
                    or row["branch"]
                )
                events.append({
                    "type": "source",
                    "claim_slug": "",
                    "source_slug": source_slug,
                    "domain": row["domain"] or "unknown",
                    "contributor": contributor,
                    "timestamp": merged_at,
                    "ci_earned": round(ci_earned, 2),
                    "summary": summary_text,
                    "pr_number": row["number"],
                    "source_channel": row["source_channel"] or "unknown",
                })
                continue

            for slug in slugs:
                if slug not in claim_activity:
                    claim_activity[slug] = {
                        "challenges": 0, "enriches": 0, "signals": 0,
                        "first_seen": merged_at,
                    }
                if event_type == "challenge":
                    claim_activity[slug]["challenges"] += 1
                elif event_type == "enrich":
                    claim_activity[slug]["enriches"] += 1
                else:
                    claim_activity[slug]["signals"] += 1

            summary_text = ""
            if row["description"]:
                first_title = row["description"].split("|")[0].strip()
                if len(first_title) > 120:
                    first_title = first_title[:117] + "..."
                summary_text = first_title
            elif row["branch"]:
                summary_text = _summary_from_branch(row["branch"])

            for slug in (slugs[:1] if slugs else [""]):
                events.append({
                    "type": event_type,
                    "claim_slug": slug,
                    "domain": row["domain"] or "unknown",
                    "contributor": contributor,
                    "timestamp": merged_at,
                    "ci_earned": round(ci_earned, 2),
                    "summary": summary_text,
                    "pr_number": row["number"],
                    "source_channel": row["source_channel"] or "unknown",
                })

        return events, claim_activity
    finally:
        conn.close()


def _sort_events(events, claim_activity, sort_mode, now_ts):
    if sort_mode == "recent":
        events.sort(key=lambda e: e["timestamp"], reverse=True)
    elif sort_mode == "hot":
        def hot_key(e):
            slug = e["claim_slug"]
            ca = claim_activity.get(slug, {"challenges": 0, "enriches": 0, "signals": 0})
            try:
                from datetime import datetime
                evt_time = datetime.fromisoformat(e["timestamp"].replace("Z", "+00:00"))
                hours = (now_ts - evt_time.timestamp()) / 3600
            except (ValueError, AttributeError):
                hours = 9999
            return _hot_score(ca["challenges"], ca["enriches"], ca["signals"], hours)
        events.sort(key=hot_key, reverse=True)
    elif sort_mode == "important":
        type_rank = {"challenge": 0, "enrich": 1, "create": 2, "source": 3}
        events.sort(key=lambda e: (type_rank.get(e["type"], 4), -len(e["summary"])))
    return events


async def handle_activity_feed(request):
    sort_mode = request.query.get("sort", "recent")
    if sort_mode not in ("hot", "recent", "important"):
        sort_mode = "recent"
    domain = request.query.get("domain", "")
    contributor = request.query.get("contributor", "")
    type_param = request.query.get("type", "")
    type_filter = {t.strip() for t in type_param.split(",") if t.strip()} if type_param else None
    try:
        limit = min(int(request.query.get("limit", "20")), 100)
    except ValueError:
        limit = 20
    try:
        offset = max(int(request.query.get("offset", "0")), 0)
    except ValueError:
        offset = 0

    now = time.time()
    if _cache["data"] is None or (now - _cache["ts"]) > CACHE_TTL:
        _cache["data"] = _build_events()
        _cache["ts"] = now

    events, claim_activity = _cache["data"]

    filtered = events
    if domain:
        filtered = [e for e in filtered if e["domain"] == domain]
    if contributor:
        filtered = [e for e in filtered if e["contributor"] == contributor]
    if type_filter:
        filtered = [e for e in filtered if e["type"] in type_filter]

    sorted_events = _sort_events(list(filtered), claim_activity, sort_mode, now)
    total = len(sorted_events)
    page = sorted_events[offset:offset + limit]

    return web.json_response({
        "events": page,
        "total": total,
        "sort": sort_mode,
        "offset": offset,
        "limit": limit,
    }, headers={"Access-Control-Allow-Origin": "*"})


def register(app):
    app.router.add_get("/api/activity-feed", handle_activity_feed)