use super::*;
use ser::text::{DnsTextData, DnsTextFormatter, next_field, quoted};

impl DnsName {
	/// Parse text representation of a domain name
	pub fn parse<'a, O>(value: &str, origin: O) -> ::errors::Result<Self>
	where
		O: IntoIterator<Item = DnsLabelRef<'a>>
	{
		let raw = value.as_bytes();
		let mut name = DnsName::new_root();
		if raw == b"." {
			return Ok(name);
		} else if raw == b"@" {
			for l in origin.into_iter() { name.push_back(l)?; }
			return Ok(name);
		}
		ensure!(!raw.is_empty(), "invalid empty name");
		let mut label = Vec::new();
		let mut pos = 0;
		while pos < raw.len() {
			if raw[pos] == b'.' {
				ensure!(!label.is_empty(), "empty label in name: {:?}", value);
				name.push_back(DnsLabelRef::new(&label)?)?;
				label.clear();
			} else if raw[pos] == b'\\' {
				ensure!(pos + 1 < raw.len(), "unexpected end of name after backslash: {:?}", value);
				if raw[pos+1] >= b'0' && raw[pos+1] <= b'9' {
					// \ddd escape
					ensure!(pos + 3 < raw.len(), "unexpected end of name after backslash with digit: {:?}", value);
					ensure!(raw[pos+2] >= b'0' && raw[pos+2] <= b'9' && raw[pos+3] >= b'0' && raw[pos+3] <= b'9', "expected three digits after backslash in name: {:?}", name);
					let d1 = (raw[pos+1] - b'0') as u32;
					let d2 = (raw[pos+2] - b'0') as u32;
					let d3 = (raw[pos+3] - b'0') as u32;
					let v = d1 * 100 + d2 * 10 + d3;
					ensure!(v < 256, "invalid escape in name, {} > 255: {:?}", v, name);
					label.push(v as u8);
				} else {
					ensure!(!quoted::is_ascii_whitespace(raw[pos+1]), "whitespace cannot be escaped with backslash prefix; encode it as \\{:03} in: {:?}", raw[pos+1], name);
					label.push(raw[pos+1]);
				}
			} else {
				ensure!(!quoted::is_ascii_whitespace(raw[pos+1]), "whitespace must be encoded as \\{:03} in: {:?}", raw[pos+1], name);
				label.push(raw[pos]);
			}
			pos += 1;
		}

		if !label.is_empty() {
			// no trailing dot, relative name
			name.push_back(DnsLabelRef::new(&label)?)?;
			for l in origin.into_iter() { name.push_back(l)?; }
		}

		Ok(name)
	}
}

impl DnsTextData for DnsName {
	fn dns_parse(data: &mut &str) -> ::errors::Result<Self> {
		let field = next_field(data)?;
		DnsName::parse(field, &DnsName::new_root())
	}

	fn dns_format(&self, f: &mut DnsTextFormatter) -> fmt::Result {
		write!(f, "{}", self)
	}
}

impl DnsCompressedName {
	/// Parse text representation of a domain name
	pub fn parse<'a, O>(value: &str, origin: O) -> ::errors::Result<Self>
	where
		O: IntoIterator<Item = DnsLabelRef<'a>>
	{
		Ok(DnsCompressedName(DnsName::parse(value, origin)?))
	}
}

impl DnsTextData for DnsCompressedName {
	fn dns_parse(data: &mut &str) -> ::errors::Result<Self> {
		let field = next_field(data)?;
		DnsCompressedName::parse(field, &DnsName::new_root())
	}

	fn dns_format(&self, f: &mut DnsTextFormatter) -> fmt::Result {
		self.0.dns_format(f)
	}
}