// SPDX-License-Identifier: BSD-3-Clause
//
// DecompileAt.java - Ghidra post-script: decompile the function containing a
// given address (no auto-analysis required).
//
// Usage (via scripts/ghidra_decompile.sh):
//   analyzeHeadless <proj> <name> -import <binary> -noanalysis \
//     -postScript DecompileAt.java <hex-vaddr> [outfile]

import ghidra.app.script.GhidraScript;
import ghidra.app.decompiler.DecompInterface;
import ghidra.app.decompiler.DecompileResults;
import ghidra.program.model.address.Address;
import ghidra.program.model.listing.Function;
import java.io.FileWriter;

public class DecompileAt extends GhidraScript {
    @Override
    public void run() throws Exception {
        String[] args = getScriptArgs();
        if (args.length < 1) {
            println("usage: DecompileAt.java <hex-vaddr> [outfile]");
            return;
        }
        long target = Long.parseUnsignedLong(args[0].replaceFirst("^0x", ""), 16);
        Address addr = toAddr(target);

        Function f = getFunctionContaining(addr);
        if (f == null) {
            disassemble(addr);
            f = createFunction(addr, null);
        }
        if (f == null) {
            println("// no function at 0x" + Long.toHexString(target));
            return;
        }

        DecompInterface dif = new DecompInterface();
        dif.toggleCCode(true);
        dif.toggleSyntaxTree(true);
        dif.openProgram(currentProgram);

        DecompileResults res = dif.decompileFunction(f, 120, monitor);
        StringBuilder sb = new StringBuilder();
        sb.append("// function ").append(f.getName())
          .append(" at 0x").append(Long.toHexString(f.getEntryPoint().getOffset()))
          .append(" containing 0x").append(Long.toHexString(target)).append("\n");
        if (res != null && res.decompileCompleted()) {
            sb.append(res.getDecompiledFunction().getC());
        } else {
            sb.append("// decompilation failed\n");
        }
        String text = sb.toString();
        if (args.length > 1) {
            try (FileWriter w = new FileWriter(args[1])) {
                w.write(text);
            }
        }
        println(text);
    }
}