package promql

import (
	"reflect"
	"testing"
)

func TestLexerNextPrev(t *testing.T) {
	var lex lexer
	lex.Init("foo bar baz")
	if lex.Token != "" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "")
	}
	if err := lex.Next(); err != nil {
		t.Fatalf("unexpeted error: %s", err)
	}
	if lex.Token != "foo" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "foo")
	}

	// Rewind before the first item.
	lex.Prev()
	if lex.Token != "" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "")
	}
	if err := lex.Next(); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if lex.Token != "foo" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "foo")
	}
	if err := lex.Next(); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if lex.Token != "bar" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "bar")
	}

	// Rewind to the first item.
	lex.Prev()
	if lex.Token != "foo" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "foo")
	}
	if err := lex.Next(); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if lex.Token != "bar" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "bar")
	}
	if err := lex.Next(); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if lex.Token != "baz" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "baz")
	}

	// Go beyond the token stream.
	if err := lex.Next(); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if lex.Token != "" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "")
	}
	if !isEOF(lex.Token) {
		t.Fatalf("expecting eof")
	}
	lex.Prev()
	if lex.Token != "baz" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "baz")
	}

	// Go multiple times lex.Next() beyond token stream.
	if err := lex.Next(); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if lex.Token != "" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "")
	}
	if !isEOF(lex.Token) {
		t.Fatalf("expecting eof")
	}
	if err := lex.Next(); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if lex.Token != "" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "")
	}
	if !isEOF(lex.Token) {
		t.Fatalf("expecting eof")
	}
	lex.Prev()
	if lex.Token != "" {
		t.Fatalf("unexpected token got: %q; want %q", lex.Token, "")
	}
	if !isEOF(lex.Token) {
		t.Fatalf("expecting eof")
	}
}

func TestLexerSuccess(t *testing.T) {
	var s string
	var expectedTokens []string

	// An empty string
	s = ""
	expectedTokens = nil
	testLexerSuccess(t, s, expectedTokens)

	// String with whitespace
	s = "  \n\t\r "
	expectedTokens = nil
	testLexerSuccess(t, s, expectedTokens)

	// Just metric name
	s = "metric"
	expectedTokens = []string{"metric"}
	testLexerSuccess(t, s, expectedTokens)

	// Metric name with spec chars
	s = ":foo.bar_"
	expectedTokens = []string{":foo.bar_"}
	testLexerSuccess(t, s, expectedTokens)

	// Metric name with window
	s = "metric[5m]  "
	expectedTokens = []string{"metric", "[", "5m", "]"}
	testLexerSuccess(t, s, expectedTokens)

	// Metric name with tag filters
	s = `  metric:12.34{a="foo", b != "bar", c=~ "x.+y", d !~ "zzz"}`
	expectedTokens = []string{`metric:12.34`, `{`, `a`, `=`, `"foo"`, `,`, `b`, `!=`, `"bar"`, `,`, `c`, `=~`, `"x.+y"`, `,`, `d`, `!~`, `"zzz"`, `}`}
	testLexerSuccess(t, s, expectedTokens)

	// Metric name with offset
	s = `   metric offset 10d   `
	expectedTokens = []string{`metric`, `offset`, `10d`}
	testLexerSuccess(t, s, expectedTokens)

	// Func call
	s = `sum  (  metric{x="y"  }  [5m] offset 10h)`
	expectedTokens = []string{`sum`, `(`, `metric`, `{`, `x`, `=`, `"y"`, `}`, `[`, `5m`, `]`, `offset`, `10h`, `)`}
	testLexerSuccess(t, s, expectedTokens)

	// Binary op
	s = `a+b or c % d and e unless f`
	expectedTokens = []string{`a`, `+`, `b`, `or`, `c`, `%`, `d`, `and`, `e`, `unless`, `f`}
	testLexerSuccess(t, s, expectedTokens)

	// Numbers
	s = `3+1.2-.23+4.5e5-78e-6+1.24e+45-NaN+Inf`
	expectedTokens = []string{`3`, `+`, `1.2`, `-`, `.23`, `+`, `4.5e5`, `-`, `78e-6`, `+`, `1.24e+45`, `-`, `NaN`, `+`, `Inf`}
	testLexerSuccess(t, s, expectedTokens)

	s = `12.34`
	expectedTokens = []string{`12.34`}
	testLexerSuccess(t, s, expectedTokens)

	// Strings
	s = `""''` + "``" + `"\\"  '\\'  "\"" '\''"\\\"\\"`
	expectedTokens = []string{`""`, `''`, "``", `"\\"`, `'\\'`, `"\""`, `'\''`, `"\\\"\\"`}
	testLexerSuccess(t, s, expectedTokens)

	s = "   `foo\\\\\\`бар`  "
	expectedTokens = []string{"`foo\\\\\\`бар`"}
	testLexerSuccess(t, s, expectedTokens)

	s = `# comment # sdf
		foobar # comment
		baz
		# yet another comment`
	expectedTokens = []string{"foobar", "baz"}
	testLexerSuccess(t, s, expectedTokens)
}

func testLexerSuccess(t *testing.T, s string, expectedTokens []string) {
	t.Helper()

	var lex lexer
	lex.Init(s)

	var tokens []string
	for {
		if err := lex.Next(); err != nil {
			t.Fatalf("unexpected error: %s", err)
		}
		if isEOF(lex.Token) {
			break
		}
		tokens = append(tokens, lex.Token)
	}
	if !reflect.DeepEqual(tokens, expectedTokens) {
		t.Fatalf("unexected tokens\ngot\n%q\nwant\n%q", tokens, expectedTokens)
	}
}

func TestLexerError(t *testing.T) {
	// Invalid identifier
	testLexerError(t, ".foo")

	// Incomplete string
	testLexerError(t, `"foobar`)
	testLexerError(t, `'`)
	testLexerError(t, "`")

	// Unrecognized char
	testLexerError(t, "тест")

	// Invalid numbers
	testLexerError(t, `.`)
	testLexerError(t, `123.`)
	testLexerError(t, `12e`)
	testLexerError(t, `1.2e`)
	testLexerError(t, `1.2E+`)
	testLexerError(t, `1.2E-`)
}

func testLexerError(t *testing.T, s string) {
	t.Helper()

	var lex lexer
	lex.Init(s)
	for {
		if err := lex.Next(); err != nil {
			// Expected error
			break
		}
		if isEOF(lex.Token) {
			t.Fatalf("expecting error during parse")
		}
	}

	// Try calling Next again. It must return error.
	if err := lex.Next(); err == nil {
		t.Fatalf("expecting non-nil error")
	}
}

func TestDurationSuccess(t *testing.T) {
	// Integer durations
	testDurationSuccess(t, "123s", 42, 123*1000)
	testDurationSuccess(t, "123m", 42, 123*60*1000)
	testDurationSuccess(t, "1h", 42, 1*60*60*1000)
	testDurationSuccess(t, "2d", 42, 2*24*60*60*1000)
	testDurationSuccess(t, "3w", 42, 3*7*24*60*60*1000)
	testDurationSuccess(t, "4y", 42, 4*365*24*60*60*1000)
	testDurationSuccess(t, "1i", 42*1000, 42*1000)
	testDurationSuccess(t, "3i", 42, 3*42)

	// Float durations
	testDurationSuccess(t, "0.234s", 42, 234)
	testDurationSuccess(t, "1.5s", 42, 1.5*1000)
	testDurationSuccess(t, "1.5m", 42, 1.5*60*1000)
	testDurationSuccess(t, "1.2h", 42, 1.2*60*60*1000)
	testDurationSuccess(t, "1.1d", 42, 1.1*24*60*60*1000)
	testDurationSuccess(t, "1.1w", 42, 1.1*7*24*60*60*1000)
	testDurationSuccess(t, "1.3y", 42, 1.3*365*24*60*60*1000)
	testDurationSuccess(t, "0.1i", 12340, 0.1*12340)
}

func testDurationSuccess(t *testing.T, s string, step, expectedD int64) {
	t.Helper()
	d, err := DurationValue(s, step)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if d != expectedD {
		t.Fatalf("unexpected duration; got %d; want %d", d, expectedD)
	}
}

func TestDurationError(t *testing.T) {
	testDurationError(t, "")
	testDurationError(t, "foo")
	testDurationError(t, "m")
	testDurationError(t, "12")
	testDurationError(t, "1.23")
	testDurationError(t, "1.23mm")
	testDurationError(t, "123q")
}

func testDurationError(t *testing.T, s string) {
	t.Helper()

	if isDuration(s) {
		t.Fatalf("unexpected valud duration %q", s)
	}

	d, err := DurationValue(s, 42)
	if err == nil {
		t.Fatalf("expecting non-nil error for duration %q", s)
	}
	if d != 0 {
		t.Fatalf("expecting zero duration; got %d", d)
	}
}