package php

import (
	"io"
	"os"
	"unsafe"
)

// #include <Zend/zend.h>
// #include "runtime.h"
import "C"

type ioContext struct {
	// Output and Error are unbuffered writers used for regular and error output,
	// respectively. If left unset, any data written into either by the calling
	// context will be lost.
	Output io.Writer
	Error  io.Writer
}

var currentContext *ioContext = nil

func write(w io.Writer, buffer unsafe.Pointer, length C.uint) C.int {
	// Do not return error if writer is unavailable.
	if w == nil {
		return C.int(length)
	}

	if written, err := w.Write(C.GoBytes(buffer, C.int(length))); err == nil {
		return C.int(written)
	}
	return -1
}

//export writeOut
func writeOut(buffer unsafe.Pointer, length C.uint) C.int {
	return write(currentContext.Output, buffer, length)
}

//export writeErr
func writeErr(buffer unsafe.Pointer, length C.uint) C.int {
	return write(currentContext.Error, buffer, length)
}

// Exec - Execute a program in the given context.
func Exec(ctx *Context, prog *program) Value {
	var retval C.zval

	// Bit of a hack to change directory and restore it again.
	if len(ctx.Path) > 0 {
		origCwd, _ := os.Getwd()
		defer os.Chdir(origCwd)
		os.Chdir(ctx.Path)
	}

	currentContext = &ctx.ioContext
	C.exec(prog.op_array, &retval)
	currentContext = nil
	return zval_to_go(retval)
}