package ph7_test

import (
	"bytes"
	"errors"
	"fmt"
	"testing"

	ph7 "git.codemonkeysoftware.net/b/go-ph7"
)

func mustSucceed(t *testing.T, err error) {
	t.Helper()
	if err != nil {
		t.Fatal(err.Error())
	}
}

func mustFail(t *testing.T, err error) {
	t.Helper()
	if err == nil {
		t.Fatal("expected error, got nil")
	}
}

func mustSucceedF(t *testing.T, f func() error) {
	t.Helper()
	err := f()
	if err != nil {
		t.Fatal(err.Error())
	}
}

func setupVM(t *testing.T, script string) (vm *ph7.VM, close func()) {
	t.Helper()
	engine, err := ph7.NewEngine()
	mustSucceed(t, err)

	vm, err = engine.Compile([]byte(script), true)
	if err != nil {
		mustSucceed(t, engine.Close())
		mustSucceed(t, err)
	}

	return vm, func() {
		mustSucceed(t, vm.Close())
		mustSucceed(t, engine.Close())
	}
}

func expectOutput(t *testing.T, vm *ph7.VM, expected string) {
	t.Helper()
	mustSucceed(t, vm.Exec())
	output, err := vm.ExtractOutput()
	mustSucceed(t, err)
	if output != expected {
		t.Fatalf("expected %q, got %q", expected, output)
	}
}

func TestCore(t *testing.T) {
	engine, err := ph7.NewEngine()
	mustSucceed(t, err)
	defer mustSucceedF(t, engine.Close)

	vm, err := engine.Compile([]byte("<?php echo 'Hello world!'; ?>"), false)
	mustSucceed(t, err)
	defer mustSucceedF(t, vm.Close)

	mustSucceed(t, vm.Exec())
	output, err := vm.ExtractOutput()
	mustSucceed(t, err)
	if output != "Hello world!" {
		t.Fatalf("unexpected output: %s", output)
	}

	mustSucceed(t, vm.Reset())

	mustSucceed(t, vm.Exec())
	output, err = vm.ExtractOutput()
	mustSucceed(t, err)
	if output != "Hello world!" {
		t.Fatalf("unexpected output: %s", output)
	}
}

func TestCompileFile(t *testing.T) {
	engine, err := ph7.NewEngine()
	mustSucceed(t, err)
	defer mustSucceedF(t, engine.Close)

	vm, err := engine.CompileFile("testdata/test_compile_file.php", false)
	mustSucceed(t, err)
	defer mustSucceedF(t, vm.Close)

	expectOutput(t, vm, "Hello world!")
}

func TestCompileError(t *testing.T) {
	engine, err := ph7.NewEngine()
	mustSucceed(t, err)
	defer mustSucceedF(t, engine.Close)

	_, err = engine.Compile([]byte("<?php 1234 echo 'Hello world!'; ?>"), false)
	mustFail(t, err)
	var target ph7.CompileError
	isCompileError := errors.As(err, &target)
	if !isCompileError || target.Msg == "" {
		t.Fatalf("expected compile error, got %#v", err)
	}
}

func TestOutputWriter(t *testing.T) {
	const source = `
		for ($x = 0; $x <= 1000; $x++) {
			echo $x;
		}`
	var expected bytes.Buffer
	for i := 0; i <= 1000; i++ {
		_, err := fmt.Fprint(&expected, i)
		mustSucceed(t, err)
	}

	vm, close := setupVM(t, source)
	defer close()

	var actual bytes.Buffer
	err := vm.SetOutputWriter(&actual)
	mustSucceed(t, err)

	mustSucceed(t, vm.Exec())

	if !bytes.Equal(expected.Bytes(), actual.Bytes()) {
		t.Fatalf("expected %s, got %s", expected.String(), actual.String())
	}
}

// TODO Test failing writer, including vm.OutputWriteError
// TODO Test setting writer twice

type CtxFunc func(*ph7.Context) error

func (r CtxFunc) Call(ctx *ph7.Context, _ []*ph7.Value) ph7.ResultCode {
	err := r(ctx)
	if err != nil {
		return r(ctx).(ph7.Error).Code
	}
	return ph7.ResultCodeOK
}

func testResultCode(t *testing.T, expectedOutput string, f CtxFunc) {
	t.Helper()
	const script = "echo doStuff();"
	vm, close := setupVM(t, script)
	defer close()

	mustSucceed(t, vm.CreateFunction("doStuff", f))
	expectOutput(t, vm, expectedOutput)
}

func TestContextWrite(t *testing.T) {
	const script = "echo doStuff();"
	vm, close := setupVM(t, script)
	defer close()

	const s = "aoeu htns"
	var written int
	f := func(ctx *ph7.Context) error {
		var err error
		written, err = ctx.Write([]byte(s))
		return err
	}

	mustSucceed(t, vm.CreateFunction("doStuff", CtxFunc(f)))
	expectOutput(t, vm, s)
	if written != len(s) {
		t.Fatalf("wrote wrong number of bytes: expected %d, got %d", len(s), written)
	}
}

func TestContextResultInt(t *testing.T) {
	testResultCode(t, "42", func(ctx *ph7.Context) error {
		return ctx.ResultInt(42)
	})
}

func TestContextResultInt64(t *testing.T) {
	testResultCode(t, "1234", func(ctx *ph7.Context) error {
		return ctx.ResultInt64(1234)
	})
}

func TestContextResultBool(t *testing.T) {
	testResultCode(t, "TRUE", func(ctx *ph7.Context) error {
		return ctx.ResultBool(true)
	})
	testResultCode(t, "", func(ctx *ph7.Context) error {
		return ctx.ResultBool(false)
	})
}

func TestContextResultDouble(t *testing.T) {
	testResultCode(t, "1.23", func(ctx *ph7.Context) error {
		return ctx.ResultDouble(1.23)
	})
}

func TestContextResultNull(t *testing.T) {
	testResultCode(t, "", (*ph7.Context).ResultNull)
}

func TestContextResultString(t *testing.T) {
	testResultCode(t, "hello", func(ctx *ph7.Context) error {
		return ctx.ResultString("hello")
	})
}

// TODO TestContextResultValue
// TODO TestContextResultResource