from contextlib import asynccontextmanager
import asyncio

from fastapi import FastAPI

from .dashboard import router as dashboard_router
from .strategy_engine import reconcile_all, reconcile_instance, run_due_ticks, get_running_strategy, pause_strategy, resume_strategy, tick_strategy
from .strategy_registry import list_available_strategy_modules
from .strategy_store import add_strategy_instance, delete_strategy_instance, list_strategy_instances, update_strategy_config, update_strategy_mode, update_strategy_state

try:
    from mcp.server.fastmcp import FastMCP
    from mcp.server.transport_security import TransportSecuritySettings
except ImportError:  # pragma: no cover
    FastMCP = None
    TransportSecuritySettings = None


async def _tick_loop(stop_event: asyncio.Event) -> None:
    while not stop_event.is_set():
        run_due_ticks()
        await asyncio.sleep(1)


@asynccontextmanager
async def lifespan(_: FastAPI):
    stop_event = asyncio.Event()
    reconcile_all()
    tick_task = asyncio.create_task(_tick_loop(stop_event))
    try:
        yield
    finally:
        stop_event.set()
        tick_task.cancel()


app = FastAPI(title="Trader MCP", lifespan=lifespan)
app.include_router(dashboard_router)


@app.get("/")
def landing():
    return {"name": "trader-mcp", "status": "ok"}


@app.get("/health")
def health():
    return {"status": "ok"}


@app.get("/strategies")
def strategies_list():
    """Return available strategy modules and configured strategy instances."""
    return {
        "available": [s.__dict__ for s in list_available_strategy_modules()],
        "configured": [s.__dict__ for s in list_strategy_instances()],
    }


@app.post("/strategies")
def strategies_add(payload: dict):
    """Create a new strategy instance from the supplied payload."""
    record = add_strategy_instance(
        id=payload["id"],
        strategy_type=payload["strategy_type"],
        account_id=payload["account_id"],
        client_id=payload.get("client_id"),
        mode=payload.get("mode", "off"),
        config=payload.get("config") or {},
        started_at=payload.get("started_at"),
        activated_at=payload.get("activated_at"),
    )
    reconcile_instance(record.id)
    return record.__dict__


@app.delete("/strategies/{instance_id}")
def strategies_delete(instance_id: str):
    """Delete a strategy instance and reconcile the runtime state."""
    result = delete_strategy_instance(instance_id)
    reconcile_instance(instance_id)
    return {"ok": result, "id": instance_id}


@app.post("/strategies/{instance_id}/mode")
def strategies_mode(instance_id: str, payload: dict):
    """Update a strategy mode and reconcile it into the runtime."""
    ok = update_strategy_mode(instance_id, payload["mode"], started_at=payload.get("started_at"), activated_at=payload.get("activated_at"))
    if ok:
        return reconcile_instance(instance_id)
    return {"ok": False, "id": instance_id}


@app.post("/strategies/{instance_id}/config")
def strategies_config(instance_id: str, payload: dict):
    """Replace a strategy config and reconcile it into the runtime."""
    ok = update_strategy_config(instance_id, payload["config"])
    if ok:
        return reconcile_instance(instance_id)
    return {"ok": False, "id": instance_id}


@app.post("/strategies/reconcile")
def strategies_reconcile():
    """Reconcile every configured strategy with the live runtime."""
    return reconcile_all()


def list_strategies() -> dict:
    """list_strategies()

    Return the configured strategy instances in a compact, standardized form.
    Each item includes the live runtime summary needed by humans and agents.
    """
    strategies = []
    for record in list_strategy_instances():
        state = record.state or {}
        strategies.append(
            {
                "id": record.id,
                "name": record.name or record.strategy_type,
                "strategy_type": record.strategy_type,
                "mode": record.mode,
                "status": "running" if record.mode != "off" else "stopped",
                "account_id": record.account_id,
                "market_symbol": record.market_symbol,
                "last_price": state.get("last_price"),
                "last_side": state.get("last_side") or state.get("last_action"),
                "open_order_count": state.get("open_order_count", 0),
            }
        )
    return {"strategies": strategies}


def get_strategy(
    instance_id: str,
    include_config: bool = False,
    include_state: bool = False,
    include_render: bool = False,
    include_debug: bool = False,
    include_report: bool = True,
) -> dict:
    """get_strategy(instance_id)

    Return one strategy record with compact live metadata.
    Expanded config, state, render, and debug data are opt-in. Report is included by default.
    """
    record = next((r for r in list_strategy_instances() if r.id == instance_id), None)
    if record is None:
        return {"ok": False, "error": "strategy not found", "id": instance_id}

    runtime = get_running_strategy(instance_id)
    state = dict(record.state or {})
    if runtime is not None:
        state = dict(runtime.instance.state or state)
        state["paused"] = runtime.paused
        state["next_tick_at"] = runtime.next_tick_at

    render = None
    if include_render and runtime is not None:
        try:
            render = runtime.instance.render()
        except Exception as exc:
            render = {"error": str(exc)}

    debug = None
    if include_debug:
        debug = state.get("debug_log") or []

    report = None
    if include_report:
        try:
            instance = runtime.instance if runtime is not None else None
            if instance is None:
                from .strategy_engine import _instantiate

                instance = _instantiate(record)
                instance.state = state
            report = instance.report()
        except Exception as exc:
            report = {"error": str(exc)}

    response = {
        "ok": True,
        "id": record.id,
        "name": record.name or record.strategy_type,
        "strategy_type": record.strategy_type,
        "mode": record.mode,
        "status": "running" if runtime is not None and not runtime.paused and record.mode != "off" else "paused" if runtime is not None and runtime.paused else "stopped",
        "account_id": record.account_id,
        "client_id": record.client_id,
        "market_symbol": record.market_symbol,
        "base_currency": record.base_currency,
        "counter_currency": record.counter_currency,
    }
    if include_config:
        response["config"] = record.config
    if include_state:
        response["state"] = state
        response["last_price"] = state.get("last_price")
        response["last_side"] = state.get("last_side") or state.get("last_action")
        response["open_order_count"] = state.get("open_order_count", 0)
        response["last_error"] = state.get("last_error", "")
    if include_report:
        response["report"] = report
    if include_render:
        response["render"] = render
    if include_debug:
        response["debug_log"] = debug
    return response


def update_strategy(instance_id: str, config: dict | None = None, state: dict | None = None) -> dict:
    """update_strategy(instance_id, config=None, state=None)

    Update the stored config and/or state for a strategy, then reconcile it.
    Use this for edits that should be persisted without changing lifecycle mode.
    """
    changed = False
    if config is not None:
        changed = update_strategy_config(instance_id, config) or changed
    if state is not None:
        changed = update_strategy_state(instance_id, state) or changed
    if changed:
        return reconcile_instance(instance_id)
    return {"ok": False, "id": instance_id}


def set_strategy_policy(instance_id: str, policy: dict) -> dict:
    """set_strategy_policy(instance_id, policy)

    Store a high-level Hermes policy on the strategy and persist it.
    Policy is intentionally abstract, for example: risk_posture and priority.
    """
    record = next((r for r in list_strategy_instances() if r.id == instance_id), None)
    if record is None:
        return {"ok": False, "id": instance_id, "error": "strategy not found"}
    if not isinstance(policy, dict):
        return {"ok": False, "id": instance_id, "error": "policy must be an object"}
    config = dict(record.config or {})
    config["policy"] = {
        "risk_posture": policy.get("risk_posture", config.get("policy", {}).get("risk_posture", "normal")),
        "priority": policy.get("priority", config.get("policy", {}).get("priority", "normal")),
        "reason": policy.get("reason", config.get("policy", {}).get("reason", "")),
        "decision_id": policy.get("decision_id", config.get("policy", {}).get("decision_id", "")),
    }
    state = dict(record.state or {})
    state["policy"] = config["policy"]
    ok_config = update_strategy_config(instance_id, config)
    ok_state = update_strategy_state(instance_id, state)
    if ok_config and ok_state:
        return reconcile_instance(instance_id)
    return {"ok": False, "id": instance_id, "error": "failed to persist policy"}


def control_strategy(instance_id: str, action: str) -> dict:
    """control_strategy(instance_id, action)

    Control a strategy with one action: start, pause, resume, stop, reconcile.
    This is the lifecycle entry point for operators and agents.
    """
    action = str(action or "").strip().lower()
    if action == "pause":
        return pause_strategy(instance_id)
    if action == "resume":
        return resume_strategy(instance_id)
    if action == "reconcile":
        return reconcile_instance(instance_id)
    if action == "start":
        ok = update_strategy_mode(instance_id, "active")
        return reconcile_instance(instance_id) if ok else {"ok": False, "id": instance_id}
    if action == "stop":
        ok = update_strategy_mode(instance_id, "off")
        return reconcile_instance(instance_id) if ok else {"ok": False, "id": instance_id}
    return {"ok": False, "id": instance_id, "error": f"unsupported action: {action}"}


def get_capabilities() -> dict:
    """get_capabilities()

    Describe the current public MCP surface and the strategy record shape.
    """
    return {
        "name": "trader-mcp",
        "tools": [
            {
                "name": "list_strategies",
                "description": "List configured strategy instances with compact live metadata.",
            },
            {
                "name": "get_strategy",
                "description": "Return one strategy record with optional render and debug data.",
                "params": {"include_render": "bool", "include_debug": "bool"},
            },
            {
                "name": "update_strategy",
                "description": "Update stored strategy config and/or state, then reconcile.",
            },
            {
                "name": "control_strategy",
                "description": "Control lifecycle or reconcile with a single action.",
                "params": {"action": "start|pause|resume|stop|reconcile"},
            },
            {
                "name": "set_strategy_policy",
                "description": "Store a high-level Hermes policy on a strategy.",
                "params": {"policy": "{risk_posture, priority, reason?, decision_id?}"},
            },
        ],
        "strategy_summary_fields": [
            "id",
            "name",
            "strategy_type",
            "mode",
            "status",
            "account_id",
            "client_id",
            "market_symbol",
            "base_currency",
            "counter_currency",
            "config",
            "state",
            "last_price",
            "last_side",
            "open_order_count",
            "last_error",
        ],
    }


# MCP (SSE)
# FastMCP mounted at /mcp with SSE at /mcp/sse (when FastMCP is available)
if FastMCP is not None:
    mcp = FastMCP(
        "trader-mcp",
        transport_security=TransportSecuritySettings(
            enable_dns_rebinding_protection=False,
        ),
    )

    mcp.tool()(list_strategies)
    mcp.tool()(get_strategy)
    mcp.tool()(update_strategy)
    mcp.tool()(control_strategy)
    mcp.tool()(set_strategy_policy)
    mcp.tool()(get_capabilities)

    app.mount("/mcp", mcp.sse_app())