#!/usr/bin/env python3
"""Calctool — terminal calculator with expression evaluation, unit conversion, and more."""
import argparse, sys, math, operator, re


def color(text, code):
    return f"\033[{code}m{text}\033[0m" if sys.stdout.isatty() else text


SAFE_OPS = {
    "+": operator.add, "-": operator.sub, "*": operator.mul,
    "/": operator.truediv, "//": operator.floordiv,
    "%": operator.mod, "**": operator.pow,
    "abs": abs, "round": round, "int": int, "float": float,
    "sqrt": math.sqrt, "sin": math.sin, "cos": math.cos,
    "tan": math.tan, "log": math.log, "log10": math.log10,
    "exp": math.exp, "ceil": math.ceil, "floor": math.floor,
    "pi": math.pi, "e": math.e, "tau": math.tau,
    "deg": math.degrees, "rad": math.radians,
    "factorial": math.factorial,
}


def safe_eval(expr):
    expr = expr.replace("^", "**")
    try:
        result = eval(expr, {"__builtins__": {}}, dict(SAFE_OPS))
        return result
    except Exception as e:
        return f"Error: {e}"


TEMPERATURE_UNITS = {
    "c": ("Celsius", lambda x: x),
    "f": ("Fahrenheit", lambda x: x),
    "k": ("Kelvin", lambda x: x),
}

LENGTH_UNITS = {
    "m": ("meters", 1), "km": ("km", 0.001), "cm": ("cm", 100),
    "mm": ("mm", 1000), "mi": ("miles", 0.000621371),
    "yd": ("yards", 1.09361), "ft": ("feet", 3.28084),
    "in": ("inches", 39.3701),
}

WEIGHT_UNITS = {
    "kg": ("kg", 1), "g": ("g", 1000), "mg": ("mg", 1_000_000),
    "lb": ("lbs", 2.20462), "oz": ("oz", 35.274),
}

AREA_UNITS = {
    "m2": ("m²", 1), "km2": ("km²", 0.000001),
    "ha": ("hectares", 0.0001), "acre": ("acres", 0.000247105),
    "ft2": ("ft²", 10.7639),
}


def convert_temp(value, from_unit, to_unit):
    # Convert to Celsius first
    if from_unit == "f":
        celsius = (value - 32) * 5 / 9
    elif from_unit == "k":
        celsius = value - 273.15
    else:
        celsius = value
    
    # Convert from Celsius to target
    if to_unit == "f":
        return celsius * 9 / 5 + 32
    elif to_unit == "k":
        return celsius + 273.15
    else:
        return celsius


def cmd_convert(args):
    try:
        value = float(args.value)
    except ValueError:
        print(f"Error: Invalid number '{args.value}'", file=sys.stderr)
        sys.exit(1)

    if args.type in ("temp", "temperature"):
        result = convert_temp(value, args.from_unit, args.to_unit)
        print(f"  {value}°{args.from_unit.upper()} = {color(f'{result:.2f}°{args.to_unit.upper()}', '32')}")
    
    elif args.type in ("len", "length"):
        unit_map = LENGTH_UNITS
        if args.from_unit in unit_map and args.to_unit in unit_map:
            base_value = value / unit_map[args.from_unit][1]
            result = base_value * unit_map[args.to_unit][1]
            print(f"  {value} {unit_map[args.from_unit][0]} = {color(f'{result:.4f}', '32')} {unit_map[args.to_unit][0]}")
        else:
            print("Error: Unknown length unit", file=sys.stderr)
    
    elif args.type in ("weight", "mass"):
        unit_map = WEIGHT_UNITS
        if args.from_unit in unit_map and args.to_unit in unit_map:
            base_value = value / unit_map[args.from_unit][1]
            result = base_value * unit_map[args.to_unit][1]
            print(f"  {value} {unit_map[args.from_unit][0]} = {color(f'{result:.4f}', '32')} {unit_map[args.to_unit][0]}")
        else:
            print("Error: Unknown weight unit", file=sys.stderr)
    
    elif args.type in ("area",):
        unit_map = AREA_UNITS
        if args.from_unit in unit_map and args.to_unit in unit_map:
            base_value = value / unit_map[args.from_unit][1]
            result = base_value * unit_map[args.to_unit][1]
            print(f"  {value} {unit_map[args.from_unit][0]} = {color(f'{result:.4f}', '32')} {unit_map[args.to_unit][0]}")
        else:
            print("Error: Unknown area unit", file=sys.stderr)


def cmd_calc(args):
    expr = " ".join(args.expression)
    result = safe_eval(expr)
    
    if isinstance(result, str) and result.startswith("Error"):
        print(f"  {color(result, '31')}", file=sys.stderr)
        sys.exit(1)
    
    if isinstance(result, float):
        if result == int(result):
            print(f"  {expr} = {color(str(int(result)), '36;1')}")
        else:
            print(f"  {expr} = {color(f'{result:.6f}'.rstrip('0').rstrip('.'), '36;1')}")
    else:
        print(f"  {expr} = {color(str(result), '36;1')}")


def main():
    parser = argparse.ArgumentParser(
        description="Calctool — terminal calculator and converter",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog=(
            "Examples:\n"
            "  calctool calc '2 + 2'\n"
            "  calctool calc 'sqrt(144) + pi'\n"
            "  calctool convert temp 100 c f\n"
            "  calctool convert length 10 m ft\n"
            "  calctool convert weight 5 kg lb\n"
        ),
    )
    parser.add_argument("--version", action="version",
                        version="calctool 1.0.0")

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

    c = sub.add_parser("calc", help="Evaluate mathematical expression")
    c.add_argument("expression", nargs="+", help="Expression to evaluate")

    conv = sub.add_parser("convert", help="Convert between units")
    conv.add_argument("type", choices=["temp", "temperature", "len", "length",
                                       "weight", "mass", "area"],
                      help="Conversion type")
    conv.add_argument("value", help="Numeric value")
    conv.add_argument("from_unit", help="Source unit")
    conv.add_argument("to_unit", help="Target unit")

    args = parser.parse_args()

    if args.command == "calc":
        cmd_calc(args)
    elif args.command == "convert":
        cmd_convert(args)


if __name__ == "__main__":
    main()