package vt220

type Grapheme *rune

func G(r rune) Grapheme {
	return &r
}

func N(r *rune) Grapheme {
	return r
}

type GraphemeTableRow [6]Grapheme
type GraphemeTable [16]GraphemeTableRow
type lookupTable map[rune][2]int

func (t lookupTable) Has(r rune) bool {
	if _, ok := t[r]; ok {
		return true
	}
	return false
}

func (t lookupTable) Get(r rune) *[2]int {
	if coords, ok := t[r]; ok {
		return &coords
	}
	return nil
}

type CharacterSet struct {
	table      GraphemeTable
	lookup     lookupTable
	dscsInter0 *byte
	dscsInter1 *byte
	dcscFinal  byte
	decdld     *ControlSequence
}

func (set CharacterSet) IsDownLineLoadable() bool {
	if set.decdld == nil {
		return false
	}
	return true
}

// Dscs returns the DEC-Select-Character-Set byte sequence for this CharacterSet.
func (set CharacterSet) Dscs() []byte {
	dscsLen := 1
	if set.dscsInter0 != nil {
		if set.dscsInter1 == nil {
			panic("Invalid DSCS intermediate 1!")
		}
		dscsLen = 3
	}
	dscs := make([]byte, dscsLen, dscsLen)
	if dscsLen == 3 {
		dscs[0] = *set.dscsInter0
		dscs[1] = *set.dscsInter1
	}
	dscs[dscsLen-1] = set.dcscFinal
	return dscs
}

func CharacterSetFromTable(t GraphemeTable, id byte) *CharacterSet {
	set := CharacterSet{}
	set.table = t
	set.dcscFinal = id
	set.lookup = lookupTable{}
	for i, row := range set.table {
		for j, graph := range row {
			if graph == nil {
				continue
			}
			set.lookup[*graph] = [2]int{i, j}
		}
	}
	return &set
}

func CharacterSetFromArray(a [94]*rune) *CharacterSet {
	gto := CharacterSet{}
	gto.lookup = lookupTable{}
	var i int
	for j, graph := range a {
		i = j / 16
		gto.table[i][j] = graph
		if graph != nil {
			gto.lookup[*graph] = [2]int{i, j}
		}
	}
	return &gto
}

var (
	mscASCIIGraphic = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	mscSupplementalGraphic = GraphemeTable{
		{N(nil), G('°'), G('À'), N(nil), G('à'), N(nil)},
		{G('¡'), G('±'), G('Á'), G('Ñ'), G('á'), G('ñ')},
		{G('¢'), G('²'), G('Â'), G('Ò'), G('â'), G('ò')},
		{G('£'), G('³'), G('Ã'), G('Ó'), G('ã'), G('ó')},
		{N(nil), N(nil), G('Ä'), G('Ô'), G('ä'), G('ô')},
		{G('¥'), G('µ'), G('Å'), G('Õ'), G('å'), G('õ')},
		{N(nil), G('¶'), G('Æ'), G('Ö'), G('æ'), G('ö')},
		{G('§'), G('·'), G('Ç'), G('Œ'), G('ç'), G('œ')},
		{G('¤'), N(nil), G('È'), G('Ø'), G('è'), G('ø')},
		{G('©'), G('¹'), G('É'), G('Ù'), G('é'), G('ù')},
		{G('ª'), G('º'), G('Ê'), G('Ú'), G('ê'), G('ú')},
		{G('«'), G('»'), G('Ë'), G('Û'), G('ë'), G('û')},
		{N(nil), G('¼'), G('Ì'), G('Ü'), G('ì'), G('ü')},
		{N(nil), G('½'), G('Í'), G('Ÿ'), G('í'), G('ÿ')},
		{N(nil), N(nil), G('Î'), N(nil), G('î'), N(nil)},
		{N(nil), G('¿'), G('Ï'), G('ß'), G('ï'), N(nil)},
	}
	specialGraphics = GraphemeTable{
		{N(nil), G('0'), G('@'), G('P'), G('♦'), G('⎻')},
		{G('!'), G('1'), G('A'), G('Q'), G('█'), G('―')},
		{G('"'), G('2'), G('B'), G('R'), G('␉'), G('⎼')},
		{G('#'), G('3'), G('C'), G('S'), G('␌'), G('⎽')},
		{G('$'), G('4'), G('D'), G('T'), G('␍'), G('├')},
		{G('%'), G('5'), G('E'), G('U'), G('␊'), G('┤')},
		{G('&'), G('6'), G('F'), G('V'), G('°'), G('┴')},
		{G('\''), G('7'), G('G'), G('W'), G('±'), G('┬')},
		{G('('), G('8'), G('H'), G('X'), G('␤'), G('│')},
		{G(')'), G('9'), G('I'), G('Y'), G('␋'), G('≤')},
		{G('*'), G(':'), G('J'), G('Z'), G('┘'), G('≥')},
		{G('+'), G(';'), G('K'), G('['), G('┐'), G('π')},
		{G(','), G('<'), G('L'), G('\\'), G('┌'), G('≠')},
		{G('-'), G('='), G('M'), G(']'), G('└'), G('£')},
		{G('.'), G('>'), G('N'), G('^'), G('┼'), G('·')},
		{G('/'), G('?'), G('O'), G('\u2800'), G('⎺'), N(nil)},
	}
	// TODO: Correct to Match docs
	nrcBritishBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcDutchBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcFinnishBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcFrenchBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcFrenchCanadianBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcGermanBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcItalianBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcNorwegianDanishBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcSpanishBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcSwedishBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
	// TODO: Correct to Match docs
	nrcSwissBase = GraphemeTable{
		{G(' '), G('0'), G('@'), G('P'), G('`'), G('p')},
		{G('!'), G('1'), G('A'), G('Q'), G('a'), G('q')},
		{G('"'), G('2'), G('B'), G('R'), G('b'), G('r')},
		{G('#'), G('3'), G('C'), G('S'), G('c'), G('s')},
		{G('$'), G('4'), G('D'), G('T'), G('d'), G('t')},
		{G('%'), G('5'), G('E'), G('U'), G('e'), G('u')},
		{G('&'), G('6'), G('F'), G('V'), G('f'), G('v')},
		{G('\''), G('7'), G('G'), G('W'), G('g'), G('w')},
		{G('('), G('8'), G('H'), G('X'), G('h'), G('x')},
		{G(')'), G('9'), G('I'), G('Y'), G('i'), G('y')},
		{G('*'), G(':'), G('J'), G('Z'), G('j'), G('z')},
		{G('+'), G(';'), G('K'), G('['), G('k'), G('{')},
		{G(','), G('<'), G('L'), G('\\'), G('l'), G('|')},
		{G('-'), G('='), G('M'), G(']'), G('m'), G('}')},
		{G('.'), G('>'), G('N'), G('^'), G('n'), G('~')},
		{G('/'), G('?'), G('O'), G('_'), G('o'), G('\u007F')},
	}
)

type MSC struct {
	ASCIIGraphic        *GraphemeTable
	SupplementalGraphic *GraphemeTable
}

type NRC struct {
	British         *GraphemeTable
	Dutch           *GraphemeTable
	Finnish         *GraphemeTable
	French          *GraphemeTable
	FrenchCanadian  *GraphemeTable
	German          *GraphemeTable
	Italian         *GraphemeTable
	NorwegianDanish *GraphemeTable
	Spanish         *GraphemeTable
	Swedish         *GraphemeTable
	Swiss           *GraphemeTable
}

var DEC = struct {
	MSC             MSC
	SpecialGraphics *GraphemeTable
	NRC             NRC
}{
	MSC: MSC{
		ASCIIGraphic:        &mscASCIIGraphic,
		SupplementalGraphic: &mscSupplementalGraphic,
	},
	SpecialGraphics: &specialGraphics,
	NRC: NRC{
		British:         &nrcBritishBase,
		Dutch:           &nrcDutchBase,
		Finnish:         &nrcFinnishBase,
		French:          &nrcFrenchBase,
		FrenchCanadian:  &nrcFrenchCanadianBase,
		German:          &nrcGermanBase,
		Italian:         &nrcItalianBase,
		NorwegianDanish: &nrcNorwegianDanishBase,
		Spanish:         &nrcSpanishBase,
		Swedish:         &nrcSwedishBase,
		Swiss:           &nrcSwissBase,
	},
}