package syntax

import "testing"

func TestCacheScansOncePerRevision(t *testing.T) {
	c := NewCache(LanguageTOML)

	c.Update("name = \"turbo\"\n", 1)
	first := c.Line(0)

	c.Update("this is different but the revision did not move", 1)

	if got := c.Line(0); len(got) != len(first) || got[0] != first[0] {
		t.Error("the cache re-scanned although the revision was unchanged")
	}
}

func TestCacheRescansWhenTheRevisionMoves(t *testing.T) {
	c := NewCache(LanguageTOML)
	c.Update("name = \"turbo\"\n", 1)

	c.Update("# only a comment\n", 2)

	if got, ok := firstClass(c.Line(0)); !ok || got != ClassComment {
		t.Errorf("after the revision moved, line 0 is %v, want comment", got)
	}
}

func TestCacheScansOnItsFirstUpdateEvenAtRevisionZero(t *testing.T) {
	c := NewCache(LanguageTOML)

	c.Update("name = \"turbo\"", 0)

	if len(c.Line(0)) == 0 {
		t.Error("the first Update produced nothing; revision zero must still be scanned")
	}
}

func TestADisabledCacheColoursNothing(t *testing.T) {
	c := NewCache(LanguageNone)

	c.Update("name = \"turbo\"", 1)

	if c.Enabled() {
		t.Error("Enabled() = true on a cache created disabled")
	}
	if len(c.Line(0)) != 0 {
		t.Error("a disabled cache produced spans")
	}
	if c.LineCount() != 0 {
		t.Errorf("LineCount() = %d on a disabled cache, want 0", c.LineCount())
	}
}

func TestSetEnabledDiscardsWhatWasScanned(t *testing.T) {
	c := NewCache(LanguageTOML)
	c.Update("name = \"turbo\"", 1)

	c.SetLanguage(LanguageNone)
	if len(c.Line(0)) != 0 {
		t.Error("turning colouring off left the previous scan behind")
	}

	c.SetLanguage(LanguageTOML)
	c.Update("name = \"turbo\"", 1) // the same revision as before
	if len(c.Line(0)) == 0 {
		t.Error("turning colouring back on must force a re-scan, not trust the stale revision")
	}
}

func TestCacheLineOutOfRange(t *testing.T) {
	c := NewCache(LanguageTOML)
	c.Update("a = 1\nb = 2", 1)

	if c.LineCount() != 2 {
		t.Fatalf("LineCount() = %d, want 2", c.LineCount())
	}
	for _, i := range []int{-1, 2, 99} {
		if c.Line(i) != nil {
			t.Errorf("Line(%d) returned spans, want nil", i)
		}
	}
}

// firstClass returns the class of the first span, if there is one.
func firstClass(spans []Span) (Class, bool) {
	if len(spans) == 0 {
		return 0, false
	}
	return spans[0].Class, true
}