#!/usr/bin/env python3
"""Explore a Sigenergy plant or inverter over Modbus TCP."""

from __future__ import annotations

import argparse
import json
from dataclasses import asdict
from os import environ

from gibil.classes.sigen.builder import SigenPlantClient
from gibil.classes.env_loader import EnvLoader
from gibil.classes.sigen.modbus import (
    ModbusReadError,
    ModbusReadResult,
    RegisterKind,
    SigenModbusClient,
)
from gibil.classes.sigen.registers import (
    DEFAULT_INVERTER_REGISTER_NAMES,
    DEFAULT_PLANT_REGISTER_NAMES,
    INVERTER_REGISTERS,
    PLANT_PARAMETER_REGISTERS,
    PLANT_REGISTERS,
    SigenRegister,
)


DEFAULT_KINDS: tuple[RegisterKind, ...] = ("holding", "input")
ALL_KINDS: tuple[RegisterKind, ...] = ("holding", "input", "coil", "discrete")
DEFAULT_UNIT_CANDIDATES = (0, 1, 2, 3, 247, 255)


def main() -> None:
    EnvLoader().load()
    args = parse_args()

    if args.command == "units":
        results = probe_units(args)
        print_results(results, errors=True)
        return
    if args.command == "catalog":
        if args.group in {"plant", "all"}:
            print_catalog("Plant Sensors", PLANT_REGISTERS)
        if args.group in {"params", "all"}:
            print_catalog("Plant Parameters", PLANT_PARAMETER_REGISTERS)
        return
    if args.command == "snapshot":
        snapshot = SigenPlantClient.from_env().fetch_snapshot()
        print(json.dumps(asdict(snapshot), indent=2, default=str))
        return

    with SigenModbusClient(
        host=args.host,
        port=args.port,
        unit_id=args.unit_id,
        timeout=args.timeout,
        retries=args.retries,
        trace=args.trace,
    ) as client:
        if args.command == "probe":
            print(
                f"Connected to {args.host}:{args.port} "
                f"with unit id {args.unit_id}"
            )
            return
        if args.command == "plant":
            print_known_registers(client, args.register, PLANT_REGISTERS)
            return
        if args.command == "inverter":
            print_known_registers(client, args.register, INVERTER_REGISTERS)
            return
        if args.command == "read":
            try:
                result = client.read(args.kind, args.address, args.count)
                print_results([result], errors=True)
            except Exception as exc:
                print(
                    f"{args.kind:8} {args.address:5} "
                    f"+{args.count:<3} ERROR {exc}"
                )
            return

        results: list[ModbusReadResult | ModbusReadError] = []
        for kind in args.kind:
            results.extend(
                client.scan(
                    kind=kind,
                    start=args.start,
                    count=args.count,
                    chunk_size=args.chunk_size,
                )
            )

    if args.json:
        print(json.dumps([asdict(result) for result in results], indent=2))
    else:
        print_results(results, errors=args.errors)


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="Minimal Modbus TCP explorer for a Sigenergy plant/inverter."
    )
    parser.add_argument(
        "--host",
        default=environ.get("SIGEN_MODBUS_HOST"),
        required="SIGEN_MODBUS_HOST" not in environ,
        help="Modbus TCP host or IP. Can also be set as SIGEN_MODBUS_HOST.",
    )
    parser.add_argument(
        "--port",
        type=int,
        default=int(environ.get("SIGEN_MODBUS_PORT", "502")),
        help="Modbus TCP port. Defaults to 502.",
    )
    parser.add_argument(
        "--unit-id",
        type=int,
        default=int(environ.get("SIGEN_MODBUS_UNIT_ID", "1")),
        help="Modbus unit/slave id. Defaults to 1.",
    )
    parser.add_argument(
        "--timeout",
        type=float,
        default=float(environ.get("SIGEN_MODBUS_TIMEOUT", "5")),
        help="Socket timeout in seconds. Defaults to 5.",
    )
    parser.add_argument(
        "--retries",
        type=int,
        default=int(environ.get("SIGEN_MODBUS_RETRIES", "3")),
        help="Modbus request retries. Defaults to 3.",
    )
    parser.add_argument(
        "--trace",
        action="store_true",
        help="Print Modbus TCP packet bytes to stderr.",
    )

    subparsers = parser.add_subparsers(dest="command", required=True)

    subparsers.add_parser("probe", help="Open a connection and report success.")
    subparsers.add_parser(
        "snapshot",
        help="Read core plant metrics and print the builder snapshot as JSON.",
    )

    catalog = subparsers.add_parser(
        "catalog",
        help="List known Sigenergy plant sensors and settable parameters.",
    )
    catalog.add_argument(
        "group",
        choices=("plant", "params", "all"),
        nargs="?",
        default="all",
        help="Catalog group to list. Defaults to all.",
    )

    units = subparsers.add_parser(
        "units",
        help="Try small reads against likely unit ids.",
    )
    units.add_argument(
        "--candidate",
        action="append",
        type=int,
        default=None,
        help=(
            "Unit id candidate to try. Repeat for multiple ids. "
            "Defaults to 0, 1, 2, 3, 247, and 255."
        ),
    )
    units.add_argument(
        "--kind",
        action="append",
        choices=ALL_KINDS,
        default=None,
        help=(
            "Register table to test. Repeat for multiple kinds. "
            "Defaults to holding and input."
        ),
    )
    units.add_argument(
        "--address",
        type=int,
        default=30000,
        help="Address to test. Defaults to 30000.",
    )
    units.add_argument(
        "--count",
        type=int,
        default=1,
        help="Number of values to request. Defaults to 1.",
    )

    plant = subparsers.add_parser(
        "plant",
        help="Read a small set of known Sigenergy plant registers.",
    )
    plant.add_argument(
        "--register",
        action="append",
        choices=sorted(PLANT_REGISTERS),
        default=None,
        help="Known plant register to read. Repeat for multiple registers.",
    )

    inverter = subparsers.add_parser(
        "inverter",
        help="Read a small set of known Sigenergy inverter registers.",
    )
    inverter.add_argument(
        "--register",
        action="append",
        choices=sorted(INVERTER_REGISTERS),
        default=None,
        help="Known inverter register to read. Repeat for multiple registers.",
    )

    read = subparsers.add_parser(
        "read",
        help="Read one raw Modbus register range.",
    )
    read.add_argument(
        "kind",
        choices=ALL_KINDS,
        help="Register table to read.",
    )
    read.add_argument(
        "address",
        type=int,
        help="Modbus address to read.",
    )
    read.add_argument(
        "count",
        type=int,
        nargs="?",
        default=1,
        help="Number of values to read. Defaults to 1.",
    )

    scan = subparsers.add_parser("scan", help="Scan register ranges in chunks.")
    scan.add_argument(
        "--kind",
        action="append",
        choices=ALL_KINDS,
        default=None,
        help=(
            "Register table to scan. Repeat for multiple kinds. "
            "Defaults to holding and input."
        ),
    )
    scan.add_argument(
        "--start",
        type=int,
        default=0,
        help="Starting zero-based Modbus address. Defaults to 0.",
    )
    scan.add_argument(
        "--count",
        type=int,
        default=100,
        help="Number of addresses to scan. Defaults to 100.",
    )
    scan.add_argument(
        "--chunk-size",
        type=int,
        default=10,
        help="Addresses per Modbus request. Defaults to 10.",
    )
    scan.add_argument(
        "--errors",
        action="store_true",
        help="Show failed chunks as well as successful reads.",
    )
    scan.add_argument(
        "--json",
        action="store_true",
        help="Print raw result objects as JSON.",
    )

    args = parser.parse_args()
    if args.command == "scan" and args.kind is None:
        args.kind = list(DEFAULT_KINDS)
    if args.command == "units":
        if args.kind is None:
            args.kind = list(DEFAULT_KINDS)
        if args.candidate is None:
            args.candidate = list(DEFAULT_UNIT_CANDIDATES)
    if args.command == "plant" and args.register is None:
        args.register = list(DEFAULT_PLANT_REGISTER_NAMES)
    if args.command == "inverter" and args.register is None:
        args.register = list(DEFAULT_INVERTER_REGISTER_NAMES)

    return args


def probe_units(args: argparse.Namespace) -> list[ModbusReadResult | ModbusReadError]:
    results: list[ModbusReadResult | ModbusReadError] = []
    for unit_id in args.candidate:
        with SigenModbusClient(
            host=args.host,
            port=args.port,
            unit_id=unit_id,
            timeout=args.timeout,
            retries=args.retries,
            trace=args.trace,
        ) as client:
            for kind in args.kind:
                try:
                    result = client.read(kind, args.address, args.count)
                    results.append(result)
                except Exception as exc:
                    results.append(
                        ModbusReadError(
                            kind=kind,
                            address=args.address,
                            count=args.count,
                            error=f"unit {unit_id}: {exc}",
                        )
                    )
    return results


def print_known_registers(
    client: SigenModbusClient,
    register_names: list[str],
    registers: dict[str, SigenRegister],
) -> None:
    for register_name in register_names:
        register = registers[register_name]
        try:
            result = client.read(register.kind, register.address, register.count)
            value = register.decode(result.values)
            unit = f" {register.unit}" if register.unit else ""
            raw_values = " ".join(str(value) for value in result.values)
            print(
                f"{register.name:32} {value}{unit:4} "
                f"({register.kind} {register.address} +{register.count}: {raw_values})"
            )
        except Exception as exc:
            print(
                f"{register.name:32} ERROR "
                f"({register.kind} {register.address} +{register.count}: {exc})"
            )


def print_catalog(title: str, registers: dict[str, SigenRegister]) -> None:
    print(title)
    print("-" * len(title))
    for register in registers.values():
        unit = register.unit or ""
        description = register.description or ""
        print(
            f"{register.name:48} {register.kind:7} "
            f"{register.address:5} +{register.count:<2} "
            f"{register.data_type:6} gain={register.gain:<7g} "
            f"{unit:5} {description}"
        )
    print()


def print_results(
    results: list[ModbusReadResult | ModbusReadError],
    errors: bool,
) -> None:
    for result in results:
        if isinstance(result, ModbusReadError):
            if errors:
                print(
                    f"{result.kind:8} {result.address:5} "
                    f"+{result.count:<3} ERROR {result.error}"
                )
            continue

        values = " ".join(str(value) for value in result.values)
        print(f"{result.kind:8} {result.address:5} +{result.count:<3} {values}")


if __name__ == "__main__":
    main()