# -*- coding: utf-8 -*-
"""Eddycoin chain selection - ONE place that decides which chain the wallet and the miners talk to.

The programs read  eddycoin_chain.json  next to themselves (Mac app: in the data folder). If the file is
missing or broken, the built-in PENDING profile below is used: the new chain is not activated yet, so the
programs make NO network calls to any real server (the placeholder host *.invalid can never resolve).

To switch every kit to the new chain once it is activated, change only eddycoin_chain.json:
  {"chain": "<new chain id>", "server": "https://<new node>", "pool": "https://<new pool>", "explorer": "https://<site>/eddycoin.html"}
Optional "servers": ["https://<node 2>", "http://<node 3>:8773", ...] = more nodes of the same chain for automatic failover
(the programs always add the local node http://127.0.0.1:8773 at the end of the list).
"""
import json, os, sys

PENDING = {"chain": "eddycoin-mainnet-pending", "label": "Eddycoin (new chain - not live yet)",
           "server": "", "pool": "", "explorer": "", "active": False}
PLACEHOLDER_SERVER = "https://new-chain-not-active.invalid"   # RFC 2606: never resolves, so nothing is contacted
NODE_PORT = 8773   # default port of an Eddycoin mainnet node (eddycoin-node/2.x)
LOCAL_NODE = "http://127.0.0.1:%d" % NODE_PORT   # Eddycoin Node running on this computer (last failover choice)


def _dirs():
    out = []
    try:
        out.append(os.path.dirname(os.path.abspath(sys.executable if getattr(sys, "frozen", False) else sys.argv[0])))
    except Exception:
        pass
    out.append(os.path.dirname(os.path.abspath(__file__)))
    if os.environ.get("EDDY_DATA_DIR"):
        out.insert(0, os.environ["EDDY_DATA_DIR"])
    return out


def load():
    c = dict(PENDING)
    for d in _dirs():
        p = os.path.join(d, "eddycoin_chain.json")
        if os.path.isfile(p):
            try:
                with open(p, encoding="utf-8") as f:
                    j = json.load(f)
                if isinstance(j, dict):
                    c.update({k: j[k] for k in ("chain", "label", "server", "pool", "explorer") if isinstance(j.get(k), str)})
                    if isinstance(j.get("servers"), list):
                        c["servers"] = [s for s in j["servers"] if isinstance(s, str) and s.strip()]
                    c["source"] = p
                break
            except Exception:
                pass
    c["server"] = c["server"].strip().rstrip("/"); c["pool"] = c["pool"].strip().rstrip("/")
    # mainnet build: a testnet id (eddycoin-testnet*) or an empty id can never activate the miners
    c["active"] = bool(c["server"]) and bool(c["chain"]) and c["chain"] != PENDING["chain"] and not c["chain"].lower().startswith("eddycoin-testnet")
    if not c["active"]:
        c["server"] = PLACEHOLDER_SERVER; c["pool"] = ""
    # failover list: main server first, then the extra nodes from chain.json, then a node on this computer
    lst = []
    for s in ([c["server"]] + list(c.get("servers") or []) + [LOCAL_NODE]) if c["active"] else [c["server"]]:
        s = s.strip().rstrip("/")
        if s and s not in lst and s != c["pool"]:
            lst.append(s)
    c["servers"] = lst
    return c


CHAIN = load()
NETWORK = CHAIN["chain"]
# mainnet chain id (GENESIS_DESIGN.md): block headers start with EDDY1-<lane>-BLOCK (replay protection vs the old testnet's EDDY-<lane>-BLOCK)
CHAIN_ID = "EDDY1"
ACTIVE = CHAIN["active"]
SERVER = CHAIN["server"]
POOL = CHAIN["pool"] or None
SERVERS = list(CHAIN["servers"])   # failover order (solo nodes only, never the pool)
EXPLORER = CHAIN["explorer"] or ((SERVER + "/eddycoin.html") if ACTIVE else "")
LABEL = CHAIN.get("label") or NETWORK


def network_ok(name):
    """a server/node answer belongs to the configured chain: EXACT match with the network id in eddycoin_chain.json
    (no prefix match, so no eddycoin-testnet* server is ever accepted)"""
    return ACTIVE and isinstance(name, str) and name == NETWORK