// Decompile functions of one program of the persistent Ghidra project.
//
// Headless usage (see tools/decompile.ps1):
//   analyzeHeadless <projectDir> sacred2 -process <module> -noanalysis
//       -scriptPath tools/ghidra -postScript Decompile.java <outFile> <addr|symbol> [...]
//
// An argument that is not a number is looked up as a symbol name (e.g. a
// decorated export). Addresses without a function (e.g. methods only
// reachable via a vtable) get one created first; run without -readOnly to
// keep those in the project.
// @category sacred2K

import java.io.File;
import java.io.PrintWriter;

import ghidra.app.cmd.disassemble.DisassembleCommand;
import ghidra.app.decompiler.DecompInterface;
import ghidra.app.decompiler.DecompileOptions;
import ghidra.app.decompiler.DecompileResults;
import ghidra.app.script.GhidraScript;
import ghidra.program.model.address.Address;
import ghidra.program.model.listing.Function;
import ghidra.program.model.symbol.SymbolIterator;

public class Decompile extends GhidraScript {

    // A hex address (0x-prefixed or 8 digits), or the address of a symbol with
    // that name.
    private Address resolve(String text) {
        if (text.matches("0x[0-9a-fA-F]+|[0-9a-fA-F]{8}")) {
            return toAddr(text);
        }
        SymbolIterator symbols = currentProgram.getSymbolTable().getSymbols(text);
        return symbols.hasNext() ? symbols.next().getAddress() : null;
    }

    @Override
    protected void run() throws Exception {
        String[] args = getScriptArgs();
        if (args.length < 2) {
            printerr("usage: Decompile.java <outFile> <address> [address...]");
            return;
        }

        DecompInterface decompiler = new DecompInterface();
        decompiler.setOptions(new DecompileOptions());
        decompiler.openProgram(currentProgram);

        try (PrintWriter out = new PrintWriter(new File(args[0]), "UTF-8")) {
            for (int i = 1; i < args.length; i++) {
                Address address = resolve(args[i]);
                if (address == null) {
                    out.println("// ==== " + args[i] + " ====");
                    out.println("// no such address or symbol");
                    continue;
                }
                Function function = getFunctionAt(address);
                if (function == null) {
                    function = getFunctionContaining(address);
                }
                if (function == null) {
                    new DisassembleCommand(address, null, true).applyTo(currentProgram, monitor);
                    function = createFunction(address, null);
                }
                out.println("// ==== " + args[i] + " ====");
                if (function == null) {
                    out.println("// could not create a function here");
                    continue;
                }
                out.println("// " + function.getName(true) + " @ " + function.getEntryPoint()
                        + " (" + function.getCallingConventionName() + ")");
                DecompileResults result = decompiler.decompileFunction(function, 120, monitor);
                if (result.decompileCompleted()) {
                    out.println(result.getDecompiledFunction().getC());
                } else {
                    out.println("// decompile failed: " + result.getErrorMessage());
                }
            }
        } finally {
            decompiler.dispose();
        }
    }
}