package tokenizer

import (
	"strings"
	"testing"

	"usebox.net/lang/tokens"
)

func TestSkipWhitespace(t *testing.T) {
	tzr := NewTokenizer("-", strings.NewReader(" \t\r\n"))
	tok, err := tzr.token()
	if err != nil {
		t.Errorf("unexpected error %s", err)
	}
	if tok.Id != tokens.Eof {
		t.Errorf("Eof expected, got %s", tok)
	}
	if tok.Loc.Line != 2 {
		t.Errorf("line == 2 expected, got %s", tok.Loc)
	}
	if tok.Loc.Column != 1 {
		t.Errorf("column == 1 expected, got %s", tok.Loc)
	}
}

func TestComments(t *testing.T) {
	for _, tt := range []struct {
		name  string
		input string
		line  int
		col   int
	}{
		{"single comment", "// a comment\n", 2, 1},
		{"ignore tokens", "// 1 + 2 is ignored\n", 2, 1},
		{"skip whitespace", "  // a comment\n", 2, 1},
		{"comment to eof", "\n// comment to eof", 2, 1},
		{"multiple comments", "// comment\n// another comment", 2, 1},
		{"whitespace before comment", "\t// comment with whitespace\n\t// comment\n", 3, 1},
		{"unicode", "// こんにちは\n", 2, 1},
	} {
		t.Run(tt.name, func(t *testing.T) {
			tzr := NewTokenizer("-", strings.NewReader(tt.input))
			tok, err := tzr.token()
			if err != nil {
				t.Errorf("unexpected error %s", err)
			}
			if tok.Id != tokens.Eof {
				t.Errorf("Eof expected, got %s", tok)
			}
			if tok.Loc.Line != tt.line {
				t.Errorf("line == %d expected, got %s", tt.line, tok.Loc)
			}
			if tok.Loc.Column != tt.col {
				t.Errorf("column == %d expected, got %s", tt.col, tok.Loc)
			}
		})
	}
}

func TestIdent(t *testing.T) {
	for _, tt := range []string{
		"ident",
		"MyIdent",
		"ident2",
		"名前",
		"__add",
	} {
		t.Run(tt, func(t *testing.T) {
			tzr := NewTokenizer("-", strings.NewReader(tt))
			tok, err := tzr.token()
			if err != nil {
				t.Errorf("unexpected error %s", err)
			}
			if tok.Id != tokens.Ident {
				t.Errorf("Ident expected, got %s", tok)
			}
			if tok.Value != tt {
				t.Errorf("value == %s expected, got %s", tt, tok.Value)
			}
		})
	}
}

func TestMultipleCalls(t *testing.T) {
	tzr := NewTokenizer("-", strings.NewReader("// comment\nident // with a comment\nanother\n"))
	for _, tt := range []string{
		"ident", "another",
	} {
		tok, err := tzr.token()
		if err != nil {
			t.Errorf("unexpected error %s", err)
		}
		if tok.Id != tokens.Ident {
			t.Errorf("Ident expected, got %s", tok)
		}
		if tok.Value != tt {
			t.Errorf("value == %s expected, got %s", tt, tok.Value)
		}
	}
}

func TestKeywords(t *testing.T) {
	tzr := NewTokenizer("-", strings.NewReader("true false var const def return number bool string func if else for in continue break"))
	for _, tt := range []tokens.TokenId{
		tokens.True,
		tokens.False,
		tokens.Var,
		tokens.Const,
		tokens.Def,
		tokens.Return,
		tokens.TNumber,
		tokens.TBool,
		tokens.TString,
		tokens.TFunc,
		tokens.If,
		tokens.Else,
		tokens.For,
		tokens.In,
		tokens.Continue,
		tokens.Break,
	} {
		tok, err := tzr.token()
		if err != nil {
			t.Errorf("unexpected error %s", err)
		}
		if tok.Id != tt {
			t.Errorf("%s expected, got %s", tt, tok)
		}
	}
}

func TestNumber(t *testing.T) {
	for _, tt := range []string{
		"1234",
		"0x4d2",
		"0b10011010010",
	} {
		tzr := NewTokenizer("-", strings.NewReader(tt))
		tok, err := tzr.token()
		if err != nil {
			t.Errorf("unexpected error %s", err)
		}
		if tok.Id != tokens.Number {
			t.Errorf("Number expected, got %s", tok)
		}
		if tok.Value != tt {
			t.Errorf("value == %s expected, got '%s'", tt, tok.Value)
		}
	}
}

func TestCharacter(t *testing.T) {
	for tt, e := range map[string]string{
		"'a'":     "a",
		"'0'":     "0",
		"'\\''":   "'",
		"' '":     " ",
		"'\\n'":   "\n",
		"'\\x0d'": "\r",
	} {
		tzr := NewTokenizer("-", strings.NewReader(tt))
		tok, err := tzr.token()
		if err != nil {
			t.Errorf("unexpected error %s", err)
		}
		if tok.Id != tokens.Char {
			t.Errorf("Number expected, got %s", tok)
		}
		if tok.Value != e {
			t.Errorf("value == %s expected, got '%s'", e, tok.Value)
		}
	}
}

func TestErrorCharacter(t *testing.T) {
	for _, tt := range []string{
		"'12'",
		"''",
		"'\\'",
		"'A",
		"'世'",
		"'\\x0'",
	} {
		tzr := NewTokenizer("-", strings.NewReader(tt))
		_, err := tzr.token()
		if err == nil {
			t.Errorf("expected error, didn't happen (input: %s)", tt)
		}
	}
}

func TestString(t *testing.T) {
	for tt, v := range map[string]string{
		"\"this is a string\"":       "this is a string",
		"\"0.1234\"":                 "0.1234",
		"\"\\\"escaped\\\" string\"": "\"escaped\" string",
		"\"\\n\\x0d\\t\"":            "\n\r\t",
		"\"Multiline\\nstring\"":     "Multiline\nstring",
	} {
		t.Run(tt, func(t *testing.T) {
			tzr := NewTokenizer("-", strings.NewReader(tt))
			tok, err := tzr.token()
			if err != nil {
				t.Errorf("unexpected error %s", err)
			}
			if tok.Id != tokens.String {
				t.Errorf("String expected, got \"%s\"", tok)
			}
			if tok.Value != v {
				t.Errorf("value == %s expected, got \"%s\"", tt, tok.Value)
			}
		})
	}
}

func TestErrorStrnig(t *testing.T) {
	tzr := NewTokenizer("-", strings.NewReader("\"string and EOF"))
	_, err := tzr.token()
	if err == nil {
		t.Errorf("expected error, didn't happen")
	}
}

func TestSingleChar(t *testing.T) {
	tzr := NewTokenizer("-", strings.NewReader("{ } ( ) [ ] ; , + - * % / . = > < ! ~ | & ^ ?"))
	for _, tt := range []tokens.TokenId{
		tokens.LBrace,
		tokens.RBrace,
		tokens.LParen,
		tokens.RParen,
		tokens.LBracket,
		tokens.RBracket,
		tokens.Semicolon,
		tokens.Comma,
		tokens.Add,
		tokens.Sub,
		tokens.Mul,
		tokens.Mod,
		tokens.Div,
		tokens.Dot,
		tokens.Assign,
		tokens.Gt,
		tokens.Lt,
		tokens.Not,
		tokens.Neg,
		tokens.BitOr,
		tokens.BitAnd,
		tokens.BitXor,
		tokens.TestE,
	} {
		tok, err := tzr.token()
		if err != nil {
			t.Errorf("unexpected error %s", err)
		}
		if tok.Id != tt {
			t.Errorf("%s expected, got %s", tt, tok)
		}
	}
}

func TestDoubleChar(t *testing.T) {
	tzr := NewTokenizer("-", strings.NewReader("|| && == != >= <= >> << !?"))
	for _, tt := range []tokens.TokenId{
		tokens.Or,
		tokens.And,
		tokens.Eq,
		tokens.Ne,
		tokens.Ge,
		tokens.Le,
		tokens.BitShr,
		tokens.BitShl,
		tokens.TagE,
	} {
		tok, err := tzr.token()
		if err != nil {
			t.Errorf("unexpected error %s", err)
		}
		if tok.Id != tt {
			t.Errorf("%s expected, got %s", tt, tok)
		}
	}
}

func TestScan(t *testing.T) {
	for _, tt := range []struct {
		name    string
		input   string
		ntokens int
	}{
		{"single line", "1 + 2", 4},
		{"multiple lines", "1 + 2\nident", 5},
		{"line starts with whitespace", "1 + 2\n\tident", 5},
	} {
		t.Run(tt.name, func(t *testing.T) {
			tzr := NewTokenizer("-", strings.NewReader(tt.input))
			ts, err := tzr.Scan()
			if err != nil {
				t.Errorf("unexpected error %s", err)
			}
			if len(ts) != tt.ntokens {
				t.Errorf("%d tokens expected, got %d", tt.ntokens, len(ts))
			}
			last := ts[len(ts)-1]
			if last.Id != tokens.Eof {
				t.Errorf("last token expected to be Eof, got %s", last)
			}
		})
	}
}