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

use super::language_server;
use super::path_to_regex::parse;
use super::path_to_regex::string_to_regex;
use super::path_to_regex::Compiler;
use super::path_to_regex::Key;
use super::path_to_regex::MatchResult;
use super::path_to_regex::Matcher;
use super::path_to_regex::StringOrNumber;
use super::path_to_regex::StringOrVec;
use super::path_to_regex::Token;

use crate::deno_dir;
use crate::file_fetcher::CacheSetting;
use crate::file_fetcher::FileFetcher;
use crate::http_cache::HttpCache;

use deno_core::error::anyhow;
use deno_core::error::AnyError;
use deno_core::error::Context;
use deno_core::resolve_url;
use deno_core::serde::Deserialize;
use deno_core::serde_json;
use deno_core::serde_json::json;
use deno_core::url::Position;
use deno_core::url::Url;
use deno_core::ModuleSpecifier;
use deno_runtime::deno_web::BlobUrlStore;
use deno_runtime::permissions::Permissions;
use log::error;
use lspower::lsp;
use regex::Regex;
use std::collections::HashMap;
use std::path::Path;

const CONFIG_PATH: &str = "/.well-known/deno-import-intellisense.json";
const COMPONENT: &percent_encoding::AsciiSet = &percent_encoding::CONTROLS
  .add(b' ')
  .add(b'"')
  .add(b'#')
  .add(b'<')
  .add(b'>')
  .add(b'?')
  .add(b'`')
  .add(b'{')
  .add(b'}')
  .add(b'/')
  .add(b':')
  .add(b';')
  .add(b'=')
  .add(b'@')
  .add(b'[')
  .add(b'\\')
  .add(b']')
  .add(b'^')
  .add(b'|')
  .add(b'$')
  .add(b'&')
  .add(b'+')
  .add(b',');

lazy_static::lazy_static! {
  static ref REPLACEMENT_VARIABLE_RE: Regex =
    Regex::new(r"\$\{\{?(\w+)\}?\}").unwrap();
}

fn base_url(url: &Url) -> String {
  url.origin().ascii_serialization()
}

#[derive(Debug)]
enum CompletorType {
  Literal(String),
  Key(Key, Option<String>),
}

/// Determine if a completion at a given offset is a string literal or a key/
/// variable.
fn get_completor_type(
  offset: usize,
  tokens: &[Token],
  match_result: &MatchResult,
) -> Option<CompletorType> {
  let mut len = 0_usize;
  for token in tokens {
    match token {
      Token::String(s) => {
        len += s.chars().count();
        if offset < len {
          return Some(CompletorType::Literal(s.clone()));
        }
      }
      Token::Key(k) => {
        if let Some(prefix) = &k.prefix {
          len += prefix.chars().count();
          if offset < len {
            return Some(CompletorType::Key(k.clone(), Some(prefix.clone())));
          }
        }
        if offset < len {
          return None;
        }
        if let StringOrNumber::String(name) = &k.name {
          let value = match_result
            .get(name)
            .map(|s| s.to_string(Some(&k)))
            .unwrap_or_default();
          len += value.chars().count();
          if offset <= len {
            return Some(CompletorType::Key(k.clone(), None));
          }
        }
        if let Some(suffix) = &k.suffix {
          len += suffix.chars().count();
          if offset <= len {
            return Some(CompletorType::Literal(suffix.clone()));
          }
        }
      }
    }
  }

  None
}

/// Convert a completion URL string from a completions configuration into a
/// fully qualified URL which can be fetched to provide the completions.
fn get_completion_endpoint(
  url: &str,
  tokens: &[Token],
  match_result: &MatchResult,
) -> Result<ModuleSpecifier, AnyError> {
  let mut url_str = url.to_string();
  for (key, value) in match_result.params.iter() {
    if let StringOrNumber::String(name) = key {
      let maybe_key = tokens.iter().find_map(|t| match t {
        Token::Key(k) if k.name == *key => Some(k),
        _ => None,
      });
      url_str =
        url_str.replace(&format!("${{{}}}", name), &value.to_string(maybe_key));
      url_str = url_str.replace(
        &format!("${{{{{}}}}}", name),
        &percent_encoding::percent_encode(
          value.to_string(maybe_key).as_bytes(),
          COMPONENT,
        )
        .to_string(),
      );
    }
  }
  resolve_url(&url_str).map_err(|err| err.into())
}

fn parse_replacement_variables<S: AsRef<str>>(s: S) -> Vec<String> {
  REPLACEMENT_VARIABLE_RE
    .captures_iter(s.as_ref())
    .filter_map(|c| c.get(1).map(|m| m.as_str().to_string()))
    .collect()
}

/// Validate a registry configuration JSON structure.
fn validate_config(config: &RegistryConfigurationJson) -> Result<(), AnyError> {
  if config.version != 1 {
    return Err(anyhow!(
      "Invalid registry configuration. Expected version 1 got {}.",
      config.version
    ));
  }
  for registry in &config.registries {
    let (_, keys) = string_to_regex(&registry.schema, None)?;
    let key_names: Vec<String> = keys.map_or_else(Vec::new, |keys| {
      keys
        .iter()
        .filter_map(|k| {
          if let StringOrNumber::String(s) = &k.name {
            Some(s.clone())
          } else {
            None
          }
        })
        .collect()
    });

    let variable_names: Vec<String> = registry
      .variables
      .iter()
      .map(|var| var.key.to_owned())
      .collect();

    for key_name in &key_names {
      if !variable_names.contains(key_name) {
        return Err(anyhow!("Invalid registry configuration. Registry with schema \"{}\" is missing variable declaration for key \"{}\".", registry.schema, key_name));
      }
    }

    for variable in &registry.variables {
      let key_index = key_names.iter().position(|key| *key == variable.key);
      let key_index = key_index.ok_or_else(||anyhow!("Invalid registry configuration. Registry with schema \"{}\" is missing a path parameter in schema for variable \"{}\".", registry.schema, variable.key))?;

      let replacement_variables = parse_replacement_variables(&variable.url);
      let limited_keys = key_names.get(0..key_index).unwrap();
      for v in replacement_variables {
        if variable.key == v {
          return Err(anyhow!("Invalid registry configuration. Url \"{}\" (for variable \"{}\" in registry with schema \"{}\") uses variable \"{}\", which is not allowed because that would be a self reference.", variable.url, variable.key, registry.schema, v));
        }

        let key_index = limited_keys.iter().position(|key| key == &v);

        if key_index.is_none() {
          return Err(anyhow!("Invalid registry configuration. Url \"{}\" (for variable \"{}\" in registry with schema \"{}\") uses variable \"{}\", which is not allowed because the schema defines \"{}\" to the right of \"{}\".", variable.url, variable.key, registry.schema, v, v, variable.key));
        }
      }
    }
  }

  Ok(())
}

#[derive(Debug, Clone, Deserialize)]
pub(crate) struct RegistryConfigurationVariable {
  /// The name of the variable.
  key: String,
  /// The URL with variable substitutions of the endpoint that will provide
  /// completions for the variable.
  url: String,
}

#[derive(Debug, Clone, Deserialize)]
pub(crate) struct RegistryConfiguration {
  /// A Express-like path which describes how URLs are composed for a registry.
  schema: String,
  /// The variables denoted in the `schema` should have a variable entry.
  variables: Vec<RegistryConfigurationVariable>,
}

/// A structure that represents the configuration of an origin and its module
/// registries.
#[derive(Debug, Deserialize)]
struct RegistryConfigurationJson {
  version: u32,
  registries: Vec<RegistryConfiguration>,
}

/// A structure which holds the information about currently configured module
/// registries and can provide completion information for URLs that match
/// one of the enabled registries.
#[derive(Debug, Clone)]
pub struct ModuleRegistry {
  origins: HashMap<String, Vec<RegistryConfiguration>>,
  file_fetcher: FileFetcher,
}

impl Default for ModuleRegistry {
  fn default() -> Self {
    let custom_root = std::env::var("DENO_DIR").map(String::into).ok();
    let dir = deno_dir::DenoDir::new(custom_root).unwrap();
    let location = dir.root.join("registries");
    let http_cache = HttpCache::new(&location);
    let cache_setting = CacheSetting::Use;
    let file_fetcher = FileFetcher::new(
      http_cache,
      cache_setting,
      true,
      None,
      BlobUrlStore::default(),
    )
    .unwrap();

    Self {
      origins: HashMap::new(),
      file_fetcher,
    }
  }
}

impl ModuleRegistry {
  pub fn new(location: &Path) -> Self {
    let http_cache = HttpCache::new(location);
    let file_fetcher = FileFetcher::new(
      http_cache,
      CacheSetting::Use,
      true,
      None,
      BlobUrlStore::default(),
    )
    .context("Error creating file fetcher in module registry.")
    .unwrap();

    Self {
      origins: HashMap::new(),
      file_fetcher,
    }
  }

  fn complete_literal(
    &self,
    s: String,
    completions: &mut HashMap<String, lsp::CompletionItem>,
    current_specifier: &str,
    offset: usize,
    range: &lsp::Range,
  ) {
    let label = if s.starts_with('/') {
      s[0..].to_string()
    } else {
      s.to_string()
    };
    let full_text = format!(
      "{}{}{}",
      &current_specifier[..offset],
      s,
      &current_specifier[offset..]
    );
    let text_edit = Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
      range: *range,
      new_text: full_text.clone(),
    }));
    let filter_text = Some(full_text);
    completions.insert(
      s,
      lsp::CompletionItem {
        label,
        kind: Some(lsp::CompletionItemKind::Folder),
        filter_text,
        sort_text: Some("1".to_string()),
        text_edit,
        ..Default::default()
      },
    );
  }

  /// Disable a registry, removing its configuration, if any, from memory.
  pub async fn disable(&mut self, origin: &str) -> Result<(), AnyError> {
    let origin = base_url(&Url::parse(origin)?);
    self.origins.remove(&origin);
    Ok(())
  }

  /// Attempt to fetch the configuration for a specific origin.
  pub(crate) async fn fetch_config(
    &self,
    origin: &str,
  ) -> Result<Vec<RegistryConfiguration>, AnyError> {
    let origin_url = Url::parse(origin)?;
    let specifier = origin_url.join(CONFIG_PATH)?;
    let file = self
      .file_fetcher
      .fetch(&specifier, &mut Permissions::allow_all())
      .await?;
    let config: RegistryConfigurationJson = serde_json::from_str(&file.source)?;
    validate_config(&config)?;
    Ok(config.registries)
  }

  /// Enable a registry by attempting to retrieve its configuration and
  /// validating it.
  pub async fn enable(&mut self, origin: &str) -> Result<(), AnyError> {
    let origin = base_url(&Url::parse(origin)?);
    #[allow(clippy::map_entry)]
    // we can't use entry().or_insert_with() because we can't use async closures
    if !self.origins.contains_key(&origin) {
      let configs = self.fetch_config(&origin).await?;
      self.origins.insert(origin, configs);
    }

    Ok(())
  }

  /// For a string specifier from the client, provide a set of completions, if
  /// any, for the specifier.
  pub async fn get_completions(
    &self,
    current_specifier: &str,
    offset: usize,
    range: &lsp::Range,
    state_snapshot: &language_server::StateSnapshot,
  ) -> Option<Vec<lsp::CompletionItem>> {
    if let Ok(specifier) = Url::parse(current_specifier) {
      let origin = base_url(&specifier);
      let origin_len = origin.chars().count();
      if offset >= origin_len {
        if let Some(registries) = self.origins.get(&origin) {
          let path = &specifier[Position::BeforePath..];
          let path_offset = offset - origin_len;
          let mut completions = HashMap::<String, lsp::CompletionItem>::new();
          let mut did_match = false;
          for registry in registries {
            let tokens = parse(&registry.schema, None)
              .map_err(|e| {
                error!(
                  "Error parsing registry schema for origin \"{}\". {}",
                  origin, e
                );
              })
              .ok()?;
            let mut i = tokens.len();
            let last_key_name =
              StringOrNumber::String(tokens.iter().last().map_or_else(
                || "".to_string(),
                |t| {
                  if let Token::Key(key) = t {
                    if let StringOrNumber::String(s) = &key.name {
                      return s.clone();
                    }
                  }
                  "".to_string()
                },
              ));
            loop {
              let matcher = Matcher::new(&tokens[..i], None)
                .map_err(|e| {
                  error!(
                    "Error creating matcher for schema for origin \"{}\". {}",
                    origin, e
                  );
                })
                .ok()?;
              if let Some(match_result) = matcher.matches(path) {
                did_match = true;
                let completor_type =
                  get_completor_type(path_offset, &tokens, &match_result);
                match completor_type {
                  Some(CompletorType::Literal(s)) => self.complete_literal(
                    s,
                    &mut completions,
                    current_specifier,
                    offset,
                    range,
                  ),
                  Some(CompletorType::Key(k, p)) => {
                    let maybe_url = registry.variables.iter().find_map(|v| {
                      if k.name == StringOrNumber::String(v.key.clone()) {
                        Some(v.url.as_str())
                      } else {
                        None
                      }
                    });
                    if let Some(url) = maybe_url {
                      if let Some(items) = self
                        .get_variable_items(url, &tokens, &match_result)
                        .await
                      {
                        let end = if p.is_some() { i + 1 } else { i };
                        let end = if end > tokens.len() {
                          tokens.len()
                        } else {
                          end
                        };
                        let compiler = Compiler::new(&tokens[..end], None);
                        for (idx, item) in items.into_iter().enumerate() {
                          let label = if let Some(p) = &p {
                            format!("{}{}", p, item)
                          } else {
                            item.clone()
                          };
                          let kind = if k.name == last_key_name {
                            Some(lsp::CompletionItemKind::File)
                          } else {
                            Some(lsp::CompletionItemKind::Folder)
                          };
                          let mut params = match_result.params.clone();
                          params.insert(
                            k.name.clone(),
                            StringOrVec::from_str(&item, &k),
                          );
                          let path =
                            compiler.to_path(&params).unwrap_or_default();
                          let mut item_specifier = Url::parse(&origin).ok()?;
                          item_specifier.set_path(&path);
                          let full_text = item_specifier.as_str();
                          let text_edit = Some(lsp::CompletionTextEdit::Edit(
                            lsp::TextEdit {
                              range: *range,
                              new_text: full_text.to_string(),
                            },
                          ));
                          let command = if k.name == last_key_name
                            && !state_snapshot
                              .sources
                              .contains_key(&item_specifier)
                          {
                            Some(lsp::Command {
                              title: "".to_string(),
                              command: "deno.cache".to_string(),
                              arguments: Some(vec![json!([item_specifier])]),
                            })
                          } else {
                            None
                          };
                          let detail = Some(format!("({})", k.name));
                          let filter_text = Some(full_text.to_string());
                          let sort_text = Some(format!("{:0>10}", idx + 1));
                          completions.insert(
                            item,
                            lsp::CompletionItem {
                              label,
                              kind,
                              detail,
                              sort_text,
                              filter_text,
                              text_edit,
                              command,
                              ..Default::default()
                            },
                          );
                        }
                      }
                    }
                  }
                  None => (),
                }
                break;
              }
              i -= 1;
              // If we have fallen though to the first token, and we still
              // didn't get a match, but the first token is a string literal, we
              // need to suggest the string literal.
              if i == 0 {
                if let Token::String(s) = &tokens[i] {
                  if s.starts_with(path) {
                    let label = s.to_string();
                    let kind = Some(lsp::CompletionItemKind::Folder);
                    let mut url = specifier.clone();
                    url.set_path(s);
                    let full_text = url.as_str();
                    let text_edit =
                      Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
                        range: *range,
                        new_text: full_text.to_string(),
                      }));
                    let filter_text = Some(full_text.to_string());
                    completions.insert(
                      s.to_string(),
                      lsp::CompletionItem {
                        label,
                        kind,
                        filter_text,
                        sort_text: Some("1".to_string()),
                        text_edit,
                        ..Default::default()
                      },
                    );
                  }
                }
                break;
              }
            }
          }
          // If we return None, other sources of completions will be looked for
          // but if we did at least match part of a registry, we should send an
          // empty vector so that no-completions will be sent back to the client
          return if completions.is_empty() && !did_match {
            None
          } else {
            Some(completions.into_iter().map(|(_, i)| i).collect())
          };
        }
      }
    }

    self.get_origin_completions(current_specifier, range)
  }

  pub fn get_origin_completions(
    &self,
    current_specifier: &str,
    range: &lsp::Range,
  ) -> Option<Vec<lsp::CompletionItem>> {
    let items = self
      .origins
      .keys()
      .filter_map(|k| {
        let mut origin = k.as_str().to_string();
        if origin.ends_with('/') {
          origin.pop();
        }
        if origin.starts_with(current_specifier) {
          let text_edit = Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
            range: *range,
            new_text: origin.clone(),
          }));
          Some(lsp::CompletionItem {
            label: origin,
            kind: Some(lsp::CompletionItemKind::Folder),
            detail: Some("(registry)".to_string()),
            sort_text: Some("2".to_string()),
            text_edit,
            ..Default::default()
          })
        } else {
          None
        }
      })
      .collect::<Vec<lsp::CompletionItem>>();
    if !items.is_empty() {
      Some(items)
    } else {
      None
    }
  }

  async fn get_variable_items(
    &self,
    url: &str,
    tokens: &[Token],
    match_result: &MatchResult,
  ) -> Option<Vec<String>> {
    let specifier = get_completion_endpoint(url, tokens, match_result)
      .map_err(|err| {
        error!("Internal error mapping endpoint \"{}\". {}", url, err);
      })
      .ok()?;
    let file = self
      .file_fetcher
      .fetch(&specifier, &mut Permissions::allow_all())
      .await
      .map_err(|err| {
        error!(
          "Internal error fetching endpoint \"{}\". {}",
          specifier, err
        );
      })
      .ok()?;
    let items: Vec<String> = serde_json::from_str(&file.source)
      .map_err(|err| {
        error!(
          "Error parsing response from endpoint \"{}\". {}",
          specifier, err
        );
      })
      .ok()?;
    Some(items)
  }
}

#[cfg(test)]
mod tests {
  use super::*;
  use crate::lsp::documents::DocumentCache;
  use crate::lsp::sources::Sources;
  use tempfile::TempDir;

  fn mock_state_snapshot(
    source_fixtures: &[(&str, &str)],
    location: &Path,
  ) -> language_server::StateSnapshot {
    let documents = DocumentCache::default();
    let sources = Sources::new(location);
    let http_cache = HttpCache::new(location);
    for (specifier, source) in source_fixtures {
      let specifier =
        resolve_url(specifier).expect("failed to create specifier");
      http_cache
        .set(&specifier, HashMap::default(), source.as_bytes())
        .expect("could not cache file");
      assert!(
        sources.get_source(&specifier).is_some(),
        "source could not be setup"
      );
    }
    language_server::StateSnapshot {
      documents,
      sources,
      ..Default::default()
    }
  }

  fn setup(sources: &[(&str, &str)]) -> language_server::StateSnapshot {
    let temp_dir = TempDir::new().expect("could not create temp dir");
    let location = temp_dir.path().join("deps");
    mock_state_snapshot(sources, &location)
  }

  #[test]
  fn test_validate_registry_configuration() {
    assert!(validate_config(&RegistryConfigurationJson {
      version: 2,
      registries: vec![],
    })
    .is_err());

    let cfg = RegistryConfigurationJson {
      version: 1,
      registries: vec![RegistryConfiguration {
        schema: "/:module@:version/:path*".to_string(),
        variables: vec![
          RegistryConfigurationVariable {
            key: "module".to_string(),
            url: "https://api.deno.land/modules?short".to_string(),
          },
          RegistryConfigurationVariable {
            key: "version".to_string(),
            url: "https://deno.land/_vsc1/module/${module}".to_string(),
          },
        ],
      }],
    };
    assert!(validate_config(&cfg).is_err());

    let cfg = RegistryConfigurationJson {
      version: 1,
      registries: vec![RegistryConfiguration {
        schema: "/:module@:version/:path*".to_string(),
        variables: vec![
          RegistryConfigurationVariable {
            key: "module".to_string(),
            url: "https://api.deno.land/modules?short".to_string(),
          },
          RegistryConfigurationVariable {
            key: "version".to_string(),
            url: "https://deno.land/_vsc1/module/${module}/${path}".to_string(),
          },
          RegistryConfigurationVariable {
            key: "path".to_string(),
            url: "https://deno.land/_vsc1/module/${module}/v/${{version}}"
              .to_string(),
          },
        ],
      }],
    };
    assert!(validate_config(&cfg).is_err());

    let cfg = RegistryConfigurationJson {
      version: 1,
      registries: vec![RegistryConfiguration {
        schema: "/:module@:version/:path*".to_string(),
        variables: vec![
          RegistryConfigurationVariable {
            key: "module".to_string(),
            url: "https://api.deno.land/modules?short".to_string(),
          },
          RegistryConfigurationVariable {
            key: "version".to_string(),
            url: "https://deno.land/_vsc1/module/${module}/v/${{version}}"
              .to_string(),
          },
          RegistryConfigurationVariable {
            key: "path".to_string(),
            url: "https://deno.land/_vsc1/module/${module}/v/${{version}}"
              .to_string(),
          },
        ],
      }],
    };
    assert!(validate_config(&cfg).is_err());

    let cfg = RegistryConfigurationJson {
      version: 1,
      registries: vec![RegistryConfiguration {
        schema: "/:module@:version/:path*".to_string(),
        variables: vec![
          RegistryConfigurationVariable {
            key: "module".to_string(),
            url: "https://api.deno.land/modules?short".to_string(),
          },
          RegistryConfigurationVariable {
            key: "version".to_string(),
            url: "https://deno.land/_vsc1/module/${module}".to_string(),
          },
          RegistryConfigurationVariable {
            key: "path".to_string(),
            url: "https://deno.land/_vsc1/module/${module}/v/${{version}}"
              .to_string(),
          },
        ],
      }],
    };
    validate_config(&cfg).unwrap();
  }

  #[tokio::test]
  async fn test_registry_completions_origin_match() {
    let _g = test_util::http_server();
    let temp_dir = TempDir::new().expect("could not create tmp");
    let location = temp_dir.path().join("registries");
    let mut module_registry = ModuleRegistry::new(&location);
    module_registry
      .enable("http://localhost:4545/")
      .await
      .expect("could not enable");
    let range = lsp::Range {
      start: lsp::Position {
        line: 0,
        character: 20,
      },
      end: lsp::Position {
        line: 0,
        character: 21,
      },
    };
    let state_snapshot = setup(&[]);
    let completions = module_registry
      .get_completions("h", 1, &range, &state_snapshot)
      .await;
    assert!(completions.is_some());
    let completions = completions.unwrap();
    assert_eq!(completions.len(), 1);
    assert_eq!(completions[0].label, "http://localhost:4545");
    assert_eq!(
      completions[0].text_edit,
      Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
        range,
        new_text: "http://localhost:4545".to_string()
      }))
    );
    let range = lsp::Range {
      start: lsp::Position {
        line: 0,
        character: 20,
      },
      end: lsp::Position {
        line: 0,
        character: 36,
      },
    };
    let completions = module_registry
      .get_completions("http://localhost", 16, &range, &state_snapshot)
      .await;
    assert!(completions.is_some());
    let completions = completions.unwrap();
    assert_eq!(completions.len(), 1);
    assert_eq!(completions[0].label, "http://localhost:4545");
    assert_eq!(
      completions[0].text_edit,
      Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
        range,
        new_text: "http://localhost:4545".to_string()
      }))
    );
  }

  #[tokio::test]
  async fn test_registry_completions() {
    let _g = test_util::http_server();
    let temp_dir = TempDir::new().expect("could not create tmp");
    let location = temp_dir.path().join("registries");
    let mut module_registry = ModuleRegistry::new(&location);
    module_registry
      .enable("http://localhost:4545/")
      .await
      .expect("could not enable");
    let state_snapshot = setup(&[]);
    let range = lsp::Range {
      start: lsp::Position {
        line: 0,
        character: 20,
      },
      end: lsp::Position {
        line: 0,
        character: 41,
      },
    };
    let completions = module_registry
      .get_completions("http://localhost:4545", 21, &range, &state_snapshot)
      .await;
    assert!(completions.is_some());
    let completions = completions.unwrap();
    assert_eq!(completions.len(), 1);
    assert_eq!(completions[0].label, "/x");
    assert_eq!(
      completions[0].text_edit,
      Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
        range,
        new_text: "http://localhost:4545/x".to_string()
      }))
    );
    let range = lsp::Range {
      start: lsp::Position {
        line: 0,
        character: 20,
      },
      end: lsp::Position {
        line: 0,
        character: 42,
      },
    };
    let completions = module_registry
      .get_completions("http://localhost:4545/", 22, &range, &state_snapshot)
      .await;
    assert!(completions.is_some());
    let completions = completions.unwrap();
    assert_eq!(completions.len(), 1);
    assert_eq!(completions[0].label, "/x");
    assert_eq!(
      completions[0].text_edit,
      Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
        range,
        new_text: "http://localhost:4545/x".to_string()
      }))
    );
    let range = lsp::Range {
      start: lsp::Position {
        line: 0,
        character: 20,
      },
      end: lsp::Position {
        line: 0,
        character: 44,
      },
    };
    let completions = module_registry
      .get_completions("http://localhost:4545/x/", 24, &range, &state_snapshot)
      .await;
    assert!(completions.is_some());
    let completions = completions.unwrap();
    assert_eq!(completions.len(), 2);
    assert!(completions[0].label == *"a" || completions[0].label == *"b");
    assert!(completions[1].label == *"a" || completions[1].label == *"b");
    let range = lsp::Range {
      start: lsp::Position {
        line: 0,
        character: 20,
      },
      end: lsp::Position {
        line: 0,
        character: 46,
      },
    };
    let completions = module_registry
      .get_completions(
        "http://localhost:4545/x/a@",
        26,
        &range,
        &state_snapshot,
      )
      .await;
    assert!(completions.is_some());
    let completions = completions.unwrap();
    assert_eq!(completions.len(), 3);
    let range = lsp::Range {
      start: lsp::Position {
        line: 0,
        character: 20,
      },
      end: lsp::Position {
        line: 0,
        character: 53,
      },
    };
    let completions = module_registry
      .get_completions(
        "http://localhost:4545/x/a@v1.0.0/",
        33,
        &range,
        &state_snapshot,
      )
      .await;
    assert!(completions.is_some());
    let completions = completions.unwrap();
    assert_eq!(completions.len(), 2);
    assert_eq!(completions[0].detail, Some("(path)".to_string()));
    assert_eq!(completions[0].kind, Some(lsp::CompletionItemKind::File));
    assert!(completions[0].command.is_some());
    assert_eq!(completions[1].detail, Some("(path)".to_string()));
    assert_eq!(completions[0].kind, Some(lsp::CompletionItemKind::File));
    assert!(completions[1].command.is_some());
  }

  #[test]
  fn test_parse_replacement_variables() {
    let actual = parse_replacement_variables(
      "https://deno.land/_vsc1/modules/${module}/v/${{version}}",
    );
    assert_eq!(actual.len(), 2);
    assert!(actual.contains(&"module".to_owned()));
    assert!(actual.contains(&"version".to_owned()));
  }
}