"""
Crypto MCP Server — FastAPI entry point.

MCP endpoints:
  GET  /tools           → list available MCP tools
  POST /tools/{name}    → call a tool

Internal:
  GET  /health          → server health + cache stats
"""

import sys
import os
sys.path.insert(0, os.path.dirname(__file__))

from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse
from fastapi.middleware.cors import CORSMiddleware

import services
from mcp_tools import MCP_TOOLS
from errors import CryptoMCPError
from cache import get_cache_stats

MCP_SPEC = {
    "protocolVersion": "2024-11-05",
    "serverInfo": {"name": "crypto-mcp", "version": "1.0.0"},
}

_sessions: dict[str, dict] = {}

app = FastAPI(
    title="Crypto MCP Server",
    description="Agent-friendly crypto market data + technical indicators",
    version="1.0.0",
)


@app.get("/")
async def root():
    return {"jsonrpc": "2.0", "result": {"tools": MCP_TOOLS}, "id": None}


@app.get("/mcp")
async def mcp_root():
    return {"jsonrpc": "2.0", "result": {"tools": MCP_TOOLS}, "id": None}


@app.post("/mcp")
async def mcp_rpc(request: Request):
    try:
        payload = await request.json()
    except Exception:
        return _rpc_error(None, -32700, "Parse error")

    if payload.get("jsonrpc") != "2.0":
        return _rpc_error(payload.get("id"), -32600, "Invalid Request")

    method = payload.get("method")
    params = payload.get("params", {}) or {}
    req_id = payload.get("id")

    try:
        if method == "initialize":
            session_id = params.get("sessionId") or _new_session_id()
            _sessions.setdefault(session_id, {"initialized": True})
            return _rpc_result(req_id, {**MCP_SPEC, "sessionId": session_id, "capabilities": {"tools": {"listChanged": False}}})

        if method in ("tools/list", "listTools"):
            return _rpc_result(req_id, {"tools": MCP_TOOLS})

        if method in ("tools/call", "callTool"):
            name = params.get("name") or params.get("toolName")
            arguments = params.get("arguments") or params.get("params") or {}
            if not name:
                return _rpc_error(req_id, -32602, "Missing tool name")
            result = await _call_tool(name, arguments)
            return _rpc_result(req_id, result)

        if method == "ping":
            return _rpc_result(req_id, {"ok": True})

        return _rpc_error(req_id, -32601, f"Method not found: {method}")
    except CryptoMCPError as exc:
        return _rpc_error(req_id, 400, exc.to_dict())


def _rpc_result(req_id, result):
    return {"jsonrpc": "2.0", "id": req_id, "result": result}


def _rpc_error(req_id, code, message):
    return {"jsonrpc": "2.0", "id": req_id, "error": {"code": code, "message": message}}


def _new_session_id() -> str:
    import uuid
    return uuid.uuid4().hex


async def _call_tool(tool_name: str, body: dict):
    match tool_name:
        case "get_price":
            return await services.get_price(_require(body, "symbol"))
        case "get_ohlcv":
            return await services.get_ohlcv(_require(body, "symbol"), body.get("timeframe", "1h"), int(body.get("limit", 100)))
        case "get_indicator":
            return await services.get_indicator(_require(body, "symbol"), _require(body, "indicator"), body.get("timeframe", "1h"), body.get("params", {}))
        case "get_market_snapshot":
            return await services.get_market_snapshot(_require(body, "symbol"))
        case "get_top_movers":
            return await services.get_top_movers(int(body.get("limit", 10)))
        case _:
            return {"error": "TOOL_NOT_FOUND", "detail": f"No tool named '{tool_name}'"}

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)


# ---------------------------------------------------------------------------
# Global error handler
# ---------------------------------------------------------------------------

@app.exception_handler(CryptoMCPError)
async def crypto_error_handler(request: Request, exc: CryptoMCPError):
    return JSONResponse(status_code=400, content=exc.to_dict())


@app.exception_handler(Exception)
async def generic_error_handler(request: Request, exc: Exception):
    return JSONResponse(
        status_code=500,
        content={"error": "INTERNAL_ERROR", "detail": str(exc)},
    )


# ---------------------------------------------------------------------------
# Health
# ---------------------------------------------------------------------------

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


# ---------------------------------------------------------------------------
# MCP Tool Registry
# ---------------------------------------------------------------------------

@app.get("/tools")
async def list_tools():
    """Return all available MCP tool definitions."""
    return {"tools": MCP_TOOLS}


# ---------------------------------------------------------------------------
# MCP Tool Dispatch
# ---------------------------------------------------------------------------

@app.post("/tools/{tool_name}")
async def call_tool(tool_name: str, request: Request):
    """
    Dispatch a tool call by name.
    Body: tool parameters as JSON object.
    """
    try:
        body = await request.json()
    except Exception:
        body = {}

    match tool_name:

        case "get_price":
            symbol = _require(body, "symbol")
            return await services.get_price(symbol)

        case "get_ohlcv":
            symbol = _require(body, "symbol")
            timeframe = body.get("timeframe", "1h")
            limit = int(body.get("limit", 100))
            return await services.get_ohlcv(symbol, timeframe, limit)

        case "get_indicator":
            symbol = _require(body, "symbol")
            indicator = _require(body, "indicator")
            timeframe = body.get("timeframe", "1h")
            params = body.get("params", {})
            return await services.get_indicator(symbol, indicator, timeframe, params)

        case "get_market_snapshot":
            symbol = _require(body, "symbol")
            return await services.get_market_snapshot(symbol)

        case "get_top_movers":
            limit = int(body.get("limit", 10))
            return await services.get_top_movers(limit)

        case _:
            return JSONResponse(
                status_code=404,
                content={"error": "TOOL_NOT_FOUND", "detail": f"No tool named '{tool_name}'"},
            )


# ---------------------------------------------------------------------------
# Helper
# ---------------------------------------------------------------------------

def _require(body: dict, key: str) -> str:
    from errors import InvalidParamsError
    val = body.get(key)
    if not val:
        raise InvalidParamsError(f"Missing required parameter: '{key}'")
    return str(val)


# ---------------------------------------------------------------------------
# Dev runner
# ---------------------------------------------------------------------------

if __name__ == "__main__":
    import uvicorn
    uvicorn.run("main:app", host="0.0.0.0", port=8505, reload=True)