// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.

// NOTE to all: the code in this crate sometimes slightly diverges from the
// precise wording of the spec, because rust-url does not expose all the
// routines exactly as the spec wants. The end behaviour should be identical.

use crate::Error;

// https://wicg.github.io/urlpattern/#canon-encoding-callbacks

// Ref: https://wicg.github.io/urlpattern/#canonicalize-a-protocol
pub fn canonicalize_protocol(value: &str) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  url::Url::parse(&format!("{value}://dummy.test"))
    .map(|url| url.scheme().to_owned())
    .map_err(Error::Url)
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-a-username
pub fn canonicalize_username(value: &str) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  let mut url = url::Url::parse("http://dummy.test").unwrap();
  // Note: unwrap is safe, because this is a HTTP url that supports username.
  url.set_username(value).unwrap();
  Ok(url.username().to_string())
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-a-password
pub fn canonicalize_password(value: &str) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  let mut url = url::Url::parse("http://dummy.test").unwrap();
  // Note: unwrap is safe, because this is a HTTP url that supports password.
  url.set_password(Some(value)).unwrap();
  Ok(url.password().unwrap().to_string())
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-a-hostname
pub fn canonicalize_hostname(value: &str) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  let mut url = url::Url::parse("http://dummy.test").unwrap();
  url::quirks::set_hostname(&mut url, value)
    .map_err(|_| Error::Url(url::ParseError::InvalidDomainCharacter))?;
  Ok(url::quirks::hostname(&url).to_string())
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-an-ipv6-hostname
pub fn canonicalize_ipv6_hostname(value: &str) -> Result<String, Error> {
  let valid_ipv6 = value
    .chars()
    .all(|c| c.is_ascii_hexdigit() || matches!(c, '[' | ']' | ':'));
  if !valid_ipv6 {
    Err(Error::Url(url::ParseError::InvalidIpv6Address))
  } else {
    Ok(value.to_ascii_lowercase())
  }
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-a-port
pub fn canonicalize_port(
  value: &str,
  mut protocol: Option<&str>,
) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  if let Some("") = protocol {
    protocol = None;
  }
  // Note: this unwrap is safe, because the protocol was previously parsed to be
  // valid.
  let mut url =
    url::Url::parse(&format!("{}://dummy.test", protocol.unwrap_or("dummy")))
      .unwrap();
  url::quirks::set_port(&mut url, value)
    .map_err(|_| Error::Url(url::ParseError::InvalidPort))?;
  Ok(url::quirks::port(&url).to_string())
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-a-pathname
pub fn canonicalize_pathname(value: &str) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  let leading_slash = value.starts_with('/');
  let modified_value = if !leading_slash {
    format!("/-{value}")
  } else {
    value.to_string()
  };
  let mut url = url::Url::parse("http://dummy.test").unwrap();
  url.set_path(&modified_value);
  let mut pathname = url::quirks::pathname(&url);

  // If the original value didn't have a leading slash, we prepended "/-".
  // Only strip this prefix if it's still there after URL parsing.
  // If the ".." segments were resolved, the "/-" prefix may have been removed.
  if !leading_slash && pathname.starts_with("/-") {
    pathname = &pathname[2..];
  }
  Ok(pathname.to_string())
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-an-opaque-pathname
pub fn canonicalize_an_opaque_pathname(value: &str) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  let mut url = url::Url::parse("data:dummy,test").unwrap();
  url.set_path(value);
  Ok(url::quirks::pathname(&url).to_string())
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-a-search
pub fn canonicalize_search(value: &str) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  let mut url = url::Url::parse("http://dummy.test").unwrap();
  url.set_query(Some(value));
  Ok(url.query().unwrap_or("").to_string())
}

// Ref: https://wicg.github.io/urlpattern/#canonicalize-a-search
pub fn canonicalize_hash(value: &str) -> Result<String, Error> {
  if value.is_empty() {
    return Ok(String::new());
  }
  let mut url = url::Url::parse("http://dummy.test").unwrap();
  url.set_fragment(Some(value));
  Ok(url.fragment().unwrap_or("").to_string())
}

#[derive(Debug, Eq, PartialEq)]
pub enum ProcessType {
  Pattern,
  Url,
}

// Ref: https://wicg.github.io/urlpattern/#process-protocol-for-init
pub fn process_protocol_init(
  value: &str,
  kind: &ProcessType,
) -> Result<String, Error> {
  let stripped_value = value.strip_suffix(':').unwrap_or(value);
  if kind == &ProcessType::Pattern {
    Ok(stripped_value.to_string())
  } else {
    canonicalize_protocol(stripped_value)
  }
}

// Ref: https://wicg.github.io/urlpattern/#process-username-for-init
pub fn process_username_init(
  value: &str,
  kind: &ProcessType,
) -> Result<String, Error> {
  if kind == &ProcessType::Pattern {
    Ok(value.to_string())
  } else {
    canonicalize_username(value)
  }
}

// Ref: https://wicg.github.io/urlpattern/#process-password-for-init
pub fn process_password_init(
  value: &str,
  kind: &ProcessType,
) -> Result<String, Error> {
  if kind == &ProcessType::Pattern {
    Ok(value.to_string())
  } else {
    canonicalize_password(value)
  }
}

// Ref: https://wicg.github.io/urlpattern/#process-hostname-for-init
pub fn process_hostname_init(
  value: &str,
  kind: &ProcessType,
) -> Result<String, Error> {
  if kind == &ProcessType::Pattern {
    Ok(value.to_string())
  } else {
    canonicalize_hostname(value)
  }
}

// Ref: https://wicg.github.io/urlpattern/#process-port-for-init
pub fn process_port_init(
  port_value: &str,
  protocol_value: Option<&str>,
  kind: &ProcessType,
) -> Result<String, Error> {
  if kind == &ProcessType::Pattern {
    Ok(port_value.to_string())
  } else {
    canonicalize_port(port_value, protocol_value)
  }
}

// Ref: https://wicg.github.io/urlpattern/#process-pathname-for-init
pub fn process_pathname_init(
  pathname_value: &str,
  protocol_value: Option<&str>,
  kind: &ProcessType,
) -> Result<String, Error> {
  if kind == &ProcessType::Pattern {
    Ok(pathname_value.to_string())
  } else {
    // A path is non-opaque if:
    // 1. The protocol is empty, OR
    // 2. The protocol is a special scheme (http, https, etc.), OR
    // 3. The pathname has a leading '/' (indicating hierarchical path)
    let is_non_opaque = match protocol_value {
      Some(protocol) if protocol.is_empty() || is_special_scheme(protocol) => {
        true
      }
      _ => {
        // For non-special schemes, treat as non-opaque if pathname starts with '/'
        pathname_value.starts_with('/')
      }
    };

    if is_non_opaque {
      canonicalize_pathname(pathname_value)
    } else {
      canonicalize_an_opaque_pathname(pathname_value)
    }
  }
}

// Ref: https://wicg.github.io/urlpattern/#process-search-for-init
pub fn process_search_init(
  value: &str,
  kind: &ProcessType,
) -> Result<String, Error> {
  let stripped_value = if value.starts_with('?') {
    value.get(1..).unwrap()
  } else {
    value
  };
  if kind == &ProcessType::Pattern {
    Ok(stripped_value.to_string())
  } else {
    canonicalize_search(stripped_value)
  }
}

// Ref: https://wicg.github.io/urlpattern/#process-hash-for-init
pub fn process_hash_init(
  value: &str,
  kind: &ProcessType,
) -> Result<String, Error> {
  let stripped_value = if value.starts_with('#') {
    value.get(1..).unwrap()
  } else {
    value
  };
  if kind == &ProcessType::Pattern {
    Ok(stripped_value.to_string())
  } else {
    canonicalize_hash(stripped_value)
  }
}

pub fn is_special_scheme(scheme: &str) -> bool {
  matches!(scheme, "http" | "https" | "ws" | "wss" | "ftp" | "file")
}

pub fn special_scheme_default_port(scheme: &str) -> Option<&'static str> {
  match scheme {
    "http" => Some("80"),
    "https" => Some("443"),
    "ws" => Some("80"),
    "wss" => Some("443"),
    "ftp" => Some("21"),
    "file" => None,
    _ => None,
  }
}

// Ref: https://urlpattern.spec.whatwg.org/#process-a-base-url-string
pub fn process_base_url(input: &str, kind: &ProcessType) -> String {
  if kind != &ProcessType::Pattern {
    input.to_string()
  } else {
    escape_pattern_string(input)
  }
}

// Ref: https://wicg.github.io/urlpattern/#escape-a-pattern-string
pub fn escape_pattern_string(input: &str) -> String {
  assert!(input.is_ascii());
  let mut result = String::new();
  for char in input.chars() {
    if matches!(char, '+' | '*' | '?' | ':' | '{' | '}' | '(' | ')' | '\\') {
      result.push('\\');
    }
    result.push(char);
  }
  result
}