package tokens

import (
	"encoding/json"
	"fmt"
)

type TokenId int

func (t TokenId) String() string {
	return tokenStr[t]
}

func (t TokenId) MarshalJSON() ([]byte, error) {
	return json.Marshal(t.String())
}

const (
	Eof TokenId = iota
	Ident

	None
	True
	False
	Var
	Const
	Def
	TNumber
	TBool
	TString
	TFunc
	TStruct
	TArray
	Return
	If
	Else
	For
	In
	Continue
	Break

	Number
	Char
	String

	Or
	And
	Eq
	Ne
	Ge
	Le
	BitShr
	BitShl
	TagE

	LBrace
	RBrace
	LParen
	RParen
	LBracket
	RBracket
	Semicolon
	Comma
	Add
	Sub
	Mul
	Mod
	Div
	Neg
	Dot
	Assign
	Gt
	Lt
	Not
	BitOr
	BitAnd
	BitXor
	TestE
)

var (
	tokenStr = []string{
		"Eof",
		"Ident",

		// keywords
		"none",
		"True",
		"False",
		"Var",
		"Const",
		"Def",
		"number",
		"bool",
		"string",
		"func",
		"struct",
		"array",
		"Return",
		"If",
		"Else",
		"For",
		"In",
		"Continue",
		"Break",

		// literals
		"Number",
		"Character",
		"String",

		// double char
		"Or",
		"And",
		"Eq",
		"NE",
		"Ge",
		"Le",
		"BitShr",
		"BitShl",
		"TagE",

		// single character
		"LBrace",
		"RBrace",
		"LParen",
		"RParen",
		"LBracket",
		"RBracket",
		"Semicolon",
		"Comma",
		"Add",
		"Sub",
		"Mul",
		"Mod",
		"Div",
		"Neg",
		"Dot",
		"Assign",
		"Gt",
		"Lt",
		"Not",
		"BitOr",
		"BitAnd",
		"BitXor",
		"TestE",
	}
)

type Location struct {
	File   string `json:"file"`
	Line   int    `json:"line"`
	Column int    `json:"col"`
}

func (l Location) String() string {
	return fmt.Sprintf("%s:%d:%d", l.File, l.Line, l.Column)
}

func (l *Location) Inc() {
	l.Column++
}

func (l *Location) Add(cols int) {
	l.Column += cols
}

func (l *Location) Eol() {
	l.Line++
	l.Column = 1
}

type Token struct {
	Id    TokenId  `json:"id"`
	Loc   Location `json:"loc"`
	Value string   `json:"val,omitempty"`
}

func (t Token) String() string {
	switch t.Id {
	case Ident:
		return fmt.Sprintf("'%s'", t.Value)
	default:
		return fmt.Sprintf("%s at %s", t.Id, t.Loc)
	}
}