#![warn(clippy::pedantic)]

use once_cell::sync::Lazy;
use std::collections::HashSet;

// This is the character set containing just the alphabetic characters
// from the ASCII character set.
pub static ALPHA: Lazy<HashSet<char>> = Lazy::new(||
    ('a'..='z')
    .chain('A'..='Z')
    .collect()
);

// This is the character set containing just numbers.
pub static DIGIT: Lazy<HashSet<char>> = Lazy::new(||
    ('0'..='9')
    .collect()
);

// This is the character set containing just the characters allowed
// in a hexadecimal digit.
pub static HEXDIG: Lazy<HashSet<char>> = Lazy::new(||
    DIGIT.iter().copied()
    .chain('A'..='F')
    .chain('a'..='f')
    .collect()
);

// This is the character set corresponds to the "unreserved" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986).
pub static UNRESERVED: Lazy<HashSet<char>> = Lazy::new(||
    ALPHA.iter()
    .chain(DIGIT.iter())
    .chain(['-', '.', '_', '~'].iter())
    .copied()
    .collect()
);

// This is the character set corresponds to the "sub-delims" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986).
pub static SUB_DELIMS: Lazy<HashSet<char>> = Lazy::new(||
    [
        '!', '$', '&', '\'', '(', ')',
        '*', '+', ',', ';', '='
    ]
    .iter()
    .copied()
    .collect()
);

// This is the character set corresponds to the second part
// of the "scheme" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986).
pub static SCHEME_NOT_FIRST: Lazy<HashSet<char>> = Lazy::new(||
    ALPHA.iter()
    .chain(DIGIT.iter())
    .chain(['+', '-', '.'].iter())
    .copied()
    .collect()
);

// This is the character set corresponds to the "pchar" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
// leaving out "pct-encoded".
pub static PCHAR_NOT_PCT_ENCODED: Lazy<HashSet<char>> = Lazy::new(||
    UNRESERVED.iter()
    .chain(SUB_DELIMS.iter())
    .chain([':', '@'].iter())
    .copied()
    .collect()
);

// This is the character set corresponds to the "query" syntax
// and the "fragment" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
// leaving out "pct-encoded".
pub static QUERY_OR_FRAGMENT_NOT_PCT_ENCODED: Lazy<HashSet<char>> = Lazy::new(||
    PCHAR_NOT_PCT_ENCODED.iter()
    .chain(['/', '?'].iter())
    .copied()
    .collect()
);

// This is the character set almost corresponds to the "query" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
// leaving out "pct-encoded", except that '+' is also excluded, because
// for some web services (e.g. AWS S3) a '+' is treated as
// synonymous with a space (' ') and thus gets misinterpreted.
pub static QUERY_NOT_PCT_ENCODED_WITHOUT_PLUS: Lazy<HashSet<char>> = Lazy::new(||
    UNRESERVED.iter()
    .chain([
        '!', '$', '&', '\'', '(', ')',
        '*', ',', ';', '=',
        ':', '@',
        '/', '?'
    ].iter())
    .copied()
    .collect()
);

// This is the character set corresponds to the "userinfo" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
// leaving out "pct-encoded".
pub static USER_INFO_NOT_PCT_ENCODED: Lazy<HashSet<char>> = Lazy::new(||
    UNRESERVED.iter()
    .chain(SUB_DELIMS.iter())
    .chain([':'].iter())
    .copied()
    .collect()
);

// This is the character set corresponds to the "reg-name" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
// leaving out "pct-encoded".
pub static REG_NAME_NOT_PCT_ENCODED: Lazy<HashSet<char>> = Lazy::new(||
    UNRESERVED.iter()
    .chain(SUB_DELIMS.iter())
    .copied()
    .collect()
);

// This is the character set corresponds to the last part of
// the "IPvFuture" syntax
// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986).
pub static IPV_FUTURE_LAST_PART: Lazy<HashSet<char>> = Lazy::new(||
    UNRESERVED.iter()
    .chain(SUB_DELIMS.iter())
    .chain([':'].iter())
    .copied()
    .collect()
);