package semantic_test

import (
	"bytes"
	"flag"
	"go/scanner"
	"path/filepath"
	"testing"

	"git.sr.ht/~mna/snow/pkg/internal/filetest"
	"git.sr.ht/~mna/snow/pkg/printer"
	"git.sr.ht/~mna/snow/pkg/semantic"
)

var testUpdateTypesTests = flag.Bool("test.update-types-tests", false, "If set, replace expected semantic types test results with actual results.")

func TestTypes(t *testing.T) {
	baseDir := "testdata"
	expectDir := filepath.Join(baseDir, "types")

	for _, fi := range filetest.SourceFiles(t, baseDir) {
		t.Run(fi.Name(), func(t *testing.T) {
			unit, err := semantic.Run(semantic.TypeAssignPass, filepath.Join(baseDir, fi.Name()))
			if unit == nil && err != nil {
				t.Fatal(err)
			}

			var ebuf bytes.Buffer
			scanner.PrintError(&ebuf, err)

			var buf bytes.Buffer
			pp := printer.Printer{W: &buf, Pos: printer.PosNone}
			for _, f := range unit.Files {
				_ = pp.PrintSemantic(f, unit.FileSet.File(f.Pos()))
			}

			filetest.DiffOutput(t, fi, buf.String(), expectDir, testUpdateTypesTests)
			filetest.DiffErrors(t, fi, ebuf.String(), expectDir, testUpdateTypesTests)

			// sanity check invariants:
			// - all expressions have a type
			// - all declarations have a type
			// - all valid (non-tuple) identifiers have a Ref
			var check visitorFunc
			check = func(n semantic.Node) semantic.Visitor {
				if n == nil {
					return nil
				}
				switch n := n.(type) {
				case semantic.Typed:
					if n.Type() == nil {
						lpos := unit.FileSet.Position(n.Pos())
						t.Fatalf("%s: no type for %s", lpos, semantic.TypeIdentString(n))
					}
					if id, ok := n.(*semantic.Ident); ok && id.Type().Valid() && id.Index < 0 {
						if id.Ref == nil {
							lpos := unit.FileSet.Position(n.Pos())
							t.Fatalf("%s: no Ref for identifier %s", lpos, id.Name)
						}
					}
				}
				return check
			}
			semantic.Walk(check, unit)
		})
	}
}