#!/usr/bin/env python3
"""Montana explorer JSON API — читает state files docker-volume montana-data."""
import os, sys, json, struct, glob, time
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse, parse_qs

DATA_DIR = os.environ.get("MT_DATA_DIR", "/var/lib/docker/volumes/montana-data/_data")
PROPOSALS = os.path.join(DATA_DIR, "proposals")
ACCOUNTS_BIN = os.path.join(DATA_DIR, "accounts.bin")
NODES_BIN = os.path.join(DATA_DIR, "nodes.bin")
CANDIDATES_BIN = os.path.join(DATA_DIR, "candidates.bin")
META_LAST = os.path.join(DATA_DIR, "meta_last_cemented.bin")
CURRENT_WIN = os.path.join(DATA_DIR, "current_window.bin")

ACCOUNT_SZ = 2059
NODE_SZ = 2098
CANDIDATE_SZ = 2082
PROPOSAL_SZ = 3722  # header; cemented envelope may be larger

def read_u64_le(path):
    try:
        with open(path, "rb") as f:
            return struct.unpack("<Q", f.read(8))[0]
    except Exception:
        return None

def parse_proposal_header(buf):
    if len(buf) < PROPOSAL_SZ:
        return None
    return {
        "prev_proposal_hash": buf[0:32].hex(),
        "window_index": struct.unpack("<Q", buf[32:40])[0],
        "protocol_version": struct.unpack("<I", buf[40:44])[0],
        "control_root": buf[44:76].hex(),
        "node_root": buf[76:108].hex(),
        "candidate_root": buf[108:140].hex(),
        "account_root": buf[140:172].hex(),
        "state_root": buf[172:204].hex(),
        "timechain_value": buf[204:236].hex(),
        "included_bundles_root": buf[236:268].hex(),
        "included_reveals_root": buf[268:300].hex(),
        "winner_endpoint": buf[300:332].hex(),
        "winner_id": buf[332:364].hex(),
        "proposer_node_id": buf[364:396].hex(),
        "target": int.from_bytes(buf[396:412], "little"),
        "fallback_depth": buf[412],
        "envelope_size": len(buf),
        "bundle_count": (struct.unpack("<H", buf[3722:3724])[0] if len(buf) >= 3724 else 0),
    }

def parse_node_record(buf):
    if len(buf) < NODE_SZ:
        return None
    return {
        "node_id": buf[0:32].hex(),
        "suite_id": struct.unpack("<H", buf[1984:1986])[0],
        "operator_account_id": buf[1986:2018].hex(),
        "start_window": struct.unpack("<Q", buf[2018:2026])[0],
        "chain_length": struct.unpack("<Q", buf[2026:2034])[0],
        "chain_length_snapshot": struct.unpack("<Q", buf[2034:2042])[0],
        "last_confirmation_window": struct.unpack("<Q", buf[2090:2098])[0],
    }

def api_status():
    last_cem = read_u64_le(META_LAST) or 0
    cur_win = read_u64_le(CURRENT_WIN) or 0
    n_acc = os.path.getsize(ACCOUNTS_BIN) // ACCOUNT_SZ if os.path.exists(ACCOUNTS_BIN) else 0
    n_node = os.path.getsize(NODES_BIN) // NODE_SZ if os.path.exists(NODES_BIN) else 0
    n_cand = os.path.getsize(CANDIDATES_BIN) // CANDIDATE_SZ if os.path.exists(CANDIDATES_BIN) else 0
    props = sorted(glob.glob(os.path.join(PROPOSALS, "*.bin")))
    return {
        "current_window": cur_win,
        "last_cemented_window": last_cem,
        "accounts": n_acc,
        "nodes": n_node,
        "candidates": n_cand,
        "proposals_archived": len(props),
        "ts": int(time.time()),
    }

def api_nodes():
    if not os.path.exists(NODES_BIN):
        return {"nodes": []}
    with open(NODES_BIN, "rb") as f:
        data = f.read()
    out = []
    for i in range(0, len(data), NODE_SZ):
        rec = parse_node_record(data[i:i + NODE_SZ])
        if rec:
            out.append(rec)
    return {"nodes": out}

def api_proposals(limit=30):
    files = sorted(glob.glob(os.path.join(PROPOSALS, "*.bin")), reverse=True)[:limit]
    out = []
    for fp in files:
        try:
            with open(fp, "rb") as f:
                buf = f.read()
            hdr = parse_proposal_header(buf)
            if hdr:
                out.append({
                    "window_index": hdr["window_index"],
                    "proposer_node_id": hdr["proposer_node_id"],
                    "winner_id": hdr["winner_id"],
                    "state_root": hdr["state_root"],
                    "envelope_size": hdr["envelope_size"],
                    "bundle_count": hdr["bundle_count"],
                })
        except Exception:
            continue
    return {"proposals": out, "count": len(out)}

def api_proposal(window):
    fp = os.path.join(PROPOSALS, f"{window:020d}.bin")
    if not os.path.exists(fp):
        return {"error": "not found"}, 404
    with open(fp, "rb") as f:
        buf = f.read()
    hdr = parse_proposal_header(buf)
    if not hdr:
        return {"error": "parse error"}, 500
    return hdr

class H(BaseHTTPRequestHandler):
    def log_message(self, *a, **k): pass
    def _send(self, body, code=200):
        body_b = json.dumps(body, ensure_ascii=False, indent=2).encode("utf-8")
        self.send_response(code)
        self.send_header("Content-Type", "application/json; charset=utf-8")
        self.send_header("Access-Control-Allow-Origin", "*")
        self.send_header("Content-Length", str(len(body_b)))
        self.end_headers()
        self.wfile.write(body_b)
    def do_GET(self):
        u = urlparse(self.path)
        q = parse_qs(u.query)
        try:
            if u.path == "/api/status":
                return self._send(api_status())
            if u.path == "/api/nodes":
                return self._send(api_nodes())
            if u.path == "/api/proposals":
                limit = min(int(q.get("limit", [30])[0]), 200)
                return self._send(api_proposals(limit))
            if u.path.startswith("/api/proposal/"):
                w = int(u.path.split("/")[-1])
                r = api_proposal(w)
                if isinstance(r, tuple): return self._send(r[0], r[1])
                return self._send(r)
            self._send({"error": "unknown route", "path": u.path}, 404)
        except Exception as e:
            self._send({"error": str(e)}, 500)

if __name__ == "__main__":
    port = int(os.environ.get("MT_EXPLORER_PORT", "5010"))
    print(f"montana-explorer listening on :{port} reading {DATA_DIR}", flush=True)
    HTTPServer(("0.0.0.0", port), H).serve_forever()