package runewidth

var EastAsianWidth = IsEastAsian()
var DefaultCondition = &Condition{EastAsianWidth}

type interval struct {
	first rune
	last  rune
}

var combining = []interval{
	{0x0300, 0x036F}, {0x0483, 0x0486}, {0x0488, 0x0489},
	{0x0591, 0x05BD}, {0x05BF, 0x05BF}, {0x05C1, 0x05C2},
	{0x05C4, 0x05C5}, {0x05C7, 0x05C7}, {0x0600, 0x0603},
	{0x0610, 0x0615}, {0x064B, 0x065E}, {0x0670, 0x0670},
	{0x06D6, 0x06E4}, {0x06E7, 0x06E8}, {0x06EA, 0x06ED},
	{0x070F, 0x070F}, {0x0711, 0x0711}, {0x0730, 0x074A},
	{0x07A6, 0x07B0}, {0x07EB, 0x07F3}, {0x0901, 0x0902},
	{0x093C, 0x093C}, {0x0941, 0x0948}, {0x094D, 0x094D},
	{0x0951, 0x0954}, {0x0962, 0x0963}, {0x0981, 0x0981},
	{0x09BC, 0x09BC}, {0x09C1, 0x09C4}, {0x09CD, 0x09CD},
	{0x09E2, 0x09E3}, {0x0A01, 0x0A02}, {0x0A3C, 0x0A3C},
	{0x0A41, 0x0A42}, {0x0A47, 0x0A48}, {0x0A4B, 0x0A4D},
	{0x0A70, 0x0A71}, {0x0A81, 0x0A82}, {0x0ABC, 0x0ABC},
	{0x0AC1, 0x0AC5}, {0x0AC7, 0x0AC8}, {0x0ACD, 0x0ACD},
	{0x0AE2, 0x0AE3}, {0x0B01, 0x0B01}, {0x0B3C, 0x0B3C},
	{0x0B3F, 0x0B3F}, {0x0B41, 0x0B43}, {0x0B4D, 0x0B4D},
	{0x0B56, 0x0B56}, {0x0B82, 0x0B82}, {0x0BC0, 0x0BC0},
	{0x0BCD, 0x0BCD}, {0x0C3E, 0x0C40}, {0x0C46, 0x0C48},
	{0x0C4A, 0x0C4D}, {0x0C55, 0x0C56}, {0x0CBC, 0x0CBC},
	{0x0CBF, 0x0CBF}, {0x0CC6, 0x0CC6}, {0x0CCC, 0x0CCD},
	{0x0CE2, 0x0CE3}, {0x0D41, 0x0D43}, {0x0D4D, 0x0D4D},
	{0x0DCA, 0x0DCA}, {0x0DD2, 0x0DD4}, {0x0DD6, 0x0DD6},
	{0x0E31, 0x0E31}, {0x0E34, 0x0E3A}, {0x0E47, 0x0E4E},
	{0x0EB1, 0x0EB1}, {0x0EB4, 0x0EB9}, {0x0EBB, 0x0EBC},
	{0x0EC8, 0x0ECD}, {0x0F18, 0x0F19}, {0x0F35, 0x0F35},
	{0x0F37, 0x0F37}, {0x0F39, 0x0F39}, {0x0F71, 0x0F7E},
	{0x0F80, 0x0F84}, {0x0F86, 0x0F87}, {0x0F90, 0x0F97},
	{0x0F99, 0x0FBC}, {0x0FC6, 0x0FC6}, {0x102D, 0x1030},
	{0x1032, 0x1032}, {0x1036, 0x1037}, {0x1039, 0x1039},
	{0x1058, 0x1059}, {0x1160, 0x11FF}, {0x135F, 0x135F},
	{0x1712, 0x1714}, {0x1732, 0x1734}, {0x1752, 0x1753},
	{0x1772, 0x1773}, {0x17B4, 0x17B5}, {0x17B7, 0x17BD},
	{0x17C6, 0x17C6}, {0x17C9, 0x17D3}, {0x17DD, 0x17DD},
	{0x180B, 0x180D}, {0x18A9, 0x18A9}, {0x1920, 0x1922},
	{0x1927, 0x1928}, {0x1932, 0x1932}, {0x1939, 0x193B},
	{0x1A17, 0x1A18}, {0x1B00, 0x1B03}, {0x1B34, 0x1B34},
	{0x1B36, 0x1B3A}, {0x1B3C, 0x1B3C}, {0x1B42, 0x1B42},
	{0x1B6B, 0x1B73}, {0x1DC0, 0x1DCA}, {0x1DFE, 0x1DFF},
	{0x200B, 0x200F}, {0x202A, 0x202E}, {0x2060, 0x2063},
	{0x206A, 0x206F}, {0x20D0, 0x20EF}, {0x302A, 0x302F},
	{0x3099, 0x309A}, {0xA806, 0xA806}, {0xA80B, 0xA80B},
	{0xA825, 0xA826}, {0xFB1E, 0xFB1E}, {0xFE00, 0xFE0F},
	{0xFE20, 0xFE23}, {0xFEFF, 0xFEFF}, {0xFFF9, 0xFFFB},
	{0x10A01, 0x10A03}, {0x10A05, 0x10A06}, {0x10A0C, 0x10A0F},
	{0x10A38, 0x10A3A}, {0x10A3F, 0x10A3F}, {0x1D167, 0x1D169},
	{0x1D173, 0x1D182}, {0x1D185, 0x1D18B}, {0x1D1AA, 0x1D1AD},
	{0x1D242, 0x1D244}, {0xE0001, 0xE0001}, {0xE0020, 0xE007F},
	{0xE0100, 0xE01EF},
}

var ambiguous = []interval{
	{0x00A1, 0x00A1}, {0x00A4, 0x00A4}, {0x00A7, 0x00A8},
	{0x00AA, 0x00AA}, {0x00AE, 0x00AE}, {0x00B0, 0x00B4},
	{0x00B6, 0x00BA}, {0x00BC, 0x00BF}, {0x00C6, 0x00C6},
	{0x00D0, 0x00D0}, {0x00D7, 0x00D8}, {0x00DE, 0x00E1},
	{0x00E6, 0x00E6}, {0x00E8, 0x00EA}, {0x00EC, 0x00ED},
	{0x00F0, 0x00F0}, {0x00F2, 0x00F3}, {0x00F7, 0x00FA},
	{0x00FC, 0x00FC}, {0x00FE, 0x00FE}, {0x0101, 0x0101},
	{0x0111, 0x0111}, {0x0113, 0x0113}, {0x011B, 0x011B},
	{0x0126, 0x0127}, {0x012B, 0x012B}, {0x0131, 0x0133},
	{0x0138, 0x0138}, {0x013F, 0x0142}, {0x0144, 0x0144},
	{0x0148, 0x014B}, {0x014D, 0x014D}, {0x0152, 0x0153},
	{0x0166, 0x0167}, {0x016B, 0x016B}, {0x01CE, 0x01CE},
	{0x01D0, 0x01D0}, {0x01D2, 0x01D2}, {0x01D4, 0x01D4},
	{0x01D6, 0x01D6}, {0x01D8, 0x01D8}, {0x01DA, 0x01DA},
	{0x01DC, 0x01DC}, {0x0251, 0x0251}, {0x0261, 0x0261},
	{0x02C4, 0x02C4}, {0x02C7, 0x02C7}, {0x02C9, 0x02CB},
	{0x02CD, 0x02CD}, {0x02D0, 0x02D0}, {0x02D8, 0x02DB},
	{0x02DD, 0x02DD}, {0x02DF, 0x02DF}, {0x0391, 0x03A1},
	{0x03A3, 0x03A9}, {0x03B1, 0x03C1}, {0x03C3, 0x03C9},
	{0x0401, 0x0401}, {0x0410, 0x044F}, {0x0451, 0x0451},
	{0x2010, 0x2010}, {0x2013, 0x2016}, {0x2018, 0x2019},
	{0x201C, 0x201D}, {0x2020, 0x2022}, {0x2024, 0x2027},
	{0x2030, 0x2030}, {0x2032, 0x2033}, {0x2035, 0x2035},
	{0x203B, 0x203B}, {0x203E, 0x203E}, {0x2074, 0x2074},
	{0x207F, 0x207F}, {0x2081, 0x2084}, {0x20AC, 0x20AC},
	{0x2103, 0x2103}, {0x2105, 0x2105}, {0x2109, 0x2109},
	{0x2113, 0x2113}, {0x2116, 0x2116}, {0x2121, 0x2122},
	{0x2126, 0x2126}, {0x212B, 0x212B}, {0x2153, 0x2154},
	{0x215B, 0x215E}, {0x2160, 0x216B}, {0x2170, 0x2179},
	{0x2190, 0x2199}, {0x21B8, 0x21B9}, {0x21D2, 0x21D2},
	{0x21D4, 0x21D4}, {0x21E7, 0x21E7}, {0x2200, 0x2200},
	{0x2202, 0x2203}, {0x2207, 0x2208}, {0x220B, 0x220B},
	{0x220F, 0x220F}, {0x2211, 0x2211}, {0x2215, 0x2215},
	{0x221A, 0x221A}, {0x221D, 0x2220}, {0x2223, 0x2223},
	{0x2225, 0x2225}, {0x2227, 0x222C}, {0x222E, 0x222E},
	{0x2234, 0x2237}, {0x223C, 0x223D}, {0x2248, 0x2248},
	{0x224C, 0x224C}, {0x2252, 0x2252}, {0x2260, 0x2261},
	{0x2264, 0x2267}, {0x226A, 0x226B}, {0x226E, 0x226F},
	{0x2282, 0x2283}, {0x2286, 0x2287}, {0x2295, 0x2295},
	{0x2299, 0x2299}, {0x22A5, 0x22A5}, {0x22BF, 0x22BF},
	{0x2312, 0x2312}, {0x2460, 0x24E9}, {0x24EB, 0x254B},
	{0x2550, 0x2573}, {0x2580, 0x258F}, {0x2592, 0x2595},
	{0x25A0, 0x25A1}, {0x25A3, 0x25A9}, {0x25B2, 0x25B3},
	{0x25B6, 0x25B7}, {0x25BC, 0x25BD}, {0x25C0, 0x25C1},
	{0x25C6, 0x25C8}, {0x25CB, 0x25CB}, {0x25CE, 0x25D1},
	{0x25E2, 0x25E5}, {0x25EF, 0x25EF}, {0x2605, 0x2606},
	{0x2609, 0x2609}, {0x260E, 0x260F}, {0x2614, 0x2615},
	{0x261C, 0x261C}, {0x261E, 0x261E}, {0x2640, 0x2640},
	{0x2642, 0x2642}, {0x2660, 0x2661}, {0x2663, 0x2665},
	{0x2667, 0x266A}, {0x266C, 0x266D}, {0x266F, 0x266F},
	{0x273D, 0x273D}, {0x2776, 0x277F}, {0xE000, 0xF8FF},
	{0xFFFD, 0xFFFD}, {0xF0000, 0xFFFFD}, {0x100000, 0x10FFFD},
}

type Condition struct {
	EastAsianWidth bool
}

func NewCondition() *Condition {
	return &Condition{EastAsianWidth}
}

// RuneWidth returns the number of cells in r.
// See http://www.unicode.org/reports/tr11/
func (c *Condition) RuneWidth(r rune) int {
	if r == 0 {
		return 0
	}
	if r < 32 || (r >= 0x7f && r < 0xa0) {
		return 1
	}
	for _, iv := range combining {
		if iv.first <= r && r <= iv.last {
			return 0
		}
	}

	if c.EastAsianWidth && IsAmbiguousWidth(r) {
		return 2
	}

	if r >= 0x1100 &&
		(r <= 0x115f || r == 0x2329 || r == 0x232a ||
			(r >= 0x2e80 && r <= 0xa4cf && r != 0x303f) ||
			(r >= 0xac00 && r <= 0xd7a3) ||
			(r >= 0xf900 && r <= 0xfaff) ||
			(r >= 0xfe30 && r <= 0xfe6f) ||
			(r >= 0xff00 && r <= 0xff60) ||
			(r >= 0xffe0 && r <= 0xffe6) ||
			(r >= 0x20000 && r <= 0x2fffd) ||
			(r >= 0x30000 && r <= 0x3fffd)) {
		return 2
	}
	return 1
}

func (c *Condition) StringWidth(s string) (width int) {
	for _, r := range []rune(s) {
		width += c.RuneWidth(r)
	}
	return width
}

func (c *Condition) Truncate(s string, w int, tail string) string {
	r := []rune(s)
	tw := StringWidth(tail)
	w -= tw
	width := 0
	i := 0
	for ; i < len(r); i++ {
		cw := RuneWidth(r[i])
		if width+cw > w {
			break
		}
		width += cw
	}
	if i == len(r) {
		return string(r[0:i])
	}
	return string(r[0:i]) + tail
}

// RuneWidth returns the number of cells in r.
// See http://www.unicode.org/reports/tr11/
func RuneWidth(r rune) int {
	return DefaultCondition.RuneWidth(r)
}

// IsAmbiguousWidth returns whether is ambiguous width or not.
func IsAmbiguousWidth(r rune) bool {
	for _, iv := range ambiguous {
		if iv.first <= r && r <= iv.last {
			return true
		}
	}
	return false
}

func StringWidth(s string) (width int) {
	return DefaultCondition.StringWidth(s)
}

func Truncate(s string, w int, tail string) string {
	return DefaultCondition.Truncate(s, w, tail)
}