#!/usr/bin/env python3
"""
Step 3: Generate .mcs configuration memory file using Vivado batch mode.

Calls Vivado with step3_write_mcs.tcl (located in the same scripts/ directory)
via -tclargs so no temporary script files are created.

Usage:
    python gen_mcs.py \
        --bit-file   "E:/project/RU_golden/RU_golden.runs/impl_1/RU_golden_top.bit" \
        --mcs-file   "E:/project/RU_golden/RU_golden.runs/impl_1/RU_golden_smod.mcs"

Exit codes:
    0 = success ("write_cfgmem completed successfully" in output)
    1 = failure
"""
import argparse
import os
import subprocess
import sys

from vivado_env import resolve_vivado_dir


def norm(path: str) -> str:
    """Normalize path to forward slashes (Vivado on Windows accepts both)."""
    return path.replace("\\", "/")


def main():
    parser = argparse.ArgumentParser(
        description="Generate .mcs from .bit via Vivado write_cfgmem"
    )
    parser.add_argument(
        "--vivado-dir",
        default=None,
        help="Vivado install root; defaults to VIVADO_ROOT from ~/skills_env.md",
    )
    parser.add_argument(
        "--bit-file",
        required=True,
        help="Full path to the .bit file",
    )
    parser.add_argument(
        "--mcs-file",
        required=True,
        help="Full path for the output .mcs file",
    )
    args = parser.parse_args()

    vivado_dir = norm(resolve_vivado_dir(args.vivado_dir))
    bit_file = norm(args.bit_file)
    mcs_file = norm(args.mcs_file)

    # Locate the TCL template alongside this script
    scripts_dir = os.path.dirname(os.path.abspath(__file__))
    tcl_template = os.path.join(scripts_dir, "step3_write_mcs.tcl").replace("\\", "/")

    # Validate inputs
    vivado_exe = os.path.join(vivado_dir, "bin", "vivado.bat")
    if not os.path.isfile(vivado_exe):
        print(f"ERROR: Vivado not found: {vivado_exe}", file=sys.stderr)
        sys.exit(1)

    if not os.path.isfile(bit_file):
        print(f"ERROR: .bit file not found: {bit_file}", file=sys.stderr)
        sys.exit(1)

    if not os.path.isfile(tcl_template):
        print(f"ERROR: TCL template not found: {tcl_template}", file=sys.stderr)
        sys.exit(1)

    cmd = [
        vivado_exe,
        "-mode", "batch",
        "-source", tcl_template,
        "-tclargs", bit_file, mcs_file,
    ]
    print(f"[gen_mcs] Vivado: {vivado_exe}")
    print(f"[gen_mcs] bit  : {bit_file}")
    print(f"[gen_mcs] mcs  : {mcs_file}")
    print()

    result = subprocess.run(cmd)
    sys.exit(result.returncode)


if __name__ == "__main__":
    main()