"use strict";

// The ext-* files are imported into the same scopes.
/* import-globals-from ext-toolkit.js */

XPCOMUtils.defineLazyModuleGetter(this, "Services",
                                  "resource://gre/modules/Services.jsm");

/* globals DEFAULT_STORE, PRIVATE_STORE */

const convertCookie = ({cookie, isPrivate}) => {
  let result = {
    name: cookie.name,
    value: cookie.value,
    domain: cookie.host,
    hostOnly: !cookie.isDomain,
    path: cookie.path,
    secure: cookie.isSecure,
    httpOnly: cookie.isHttpOnly,
    session: cookie.isSession,
  };

  if (!cookie.isSession) {
    result.expirationDate = cookie.expiry;
  }

  if (cookie.originAttributes.userContextId) {
    result.storeId = getCookieStoreIdForContainer(cookie.originAttributes.userContextId);
  } else if (cookie.originAttributes.privateBrowsingId || isPrivate) {
    result.storeId = PRIVATE_STORE;
  } else {
    result.storeId = DEFAULT_STORE;
  }

  return result;
};

const isSubdomain = (otherDomain, baseDomain) => {
  return otherDomain == baseDomain || otherDomain.endsWith("." + baseDomain);
};

// Checks that the given extension has permission to set the given cookie for
// the given URI.
const checkSetCookiePermissions = (extension, uri, cookie) => {
  // Permission checks:
  //
  //  - If the extension does not have permissions for the specified
  //    URL, it cannot set cookies for it.
  //
  //  - If the specified URL could not set the given cookie, neither can
  //    the extension.
  //
  // Ideally, we would just have the cookie service make the latter
  // determination, but that turns out to be quite complicated. At the
  // moment, it requires constructing a cookie string and creating a
  // dummy channel, both of which can be problematic. It also triggers
  // a whole set of additional permission and preference checks, which
  // may or may not be desirable.
  //
  // So instead, we do a similar set of checks here. Exactly what
  // cookies a given URL should be able to set is not well-documented,
  // and is not standardized in any standard that anyone actually
  // follows. So instead, we follow the rules used by the cookie
  // service.
  //
  // See source/netwerk/cookie/nsCookieService.cpp, in particular
  // CheckDomain() and SetCookieInternal().

  if (uri.scheme != "http" && uri.scheme != "https") {
    return false;
  }

  if (!extension.whiteListedHosts.matches(uri)) {
    return false;
  }

  if (!cookie.host) {
    // If no explicit host is specified, this becomes a host-only cookie.
    cookie.host = uri.host;
    return true;
  }

  // A leading "." is not expected, but is tolerated if it's not the only
  // character in the host. If there is one, start by stripping it off. We'll
  // add a new one on success.
  if (cookie.host.length > 1) {
    cookie.host = cookie.host.replace(/^\./, "");
  }
  cookie.host = cookie.host.toLowerCase();

  if (cookie.host != uri.host) {
    // Not an exact match, so check for a valid subdomain.
    let baseDomain;
    try {
      baseDomain = Services.eTLD.getBaseDomain(uri);
    } catch (e) {
      if (e.result == Cr.NS_ERROR_HOST_IS_IP_ADDRESS ||
          e.result == Cr.NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS) {
        // The cookie service uses these to determine whether the domain
        // requires an exact match. We already know we don't have an exact
        // match, so return false. In all other cases, re-raise the error.
        return false;
      }
      throw e;
    }

    // The cookie domain must be a subdomain of the base domain. This prevents
    // us from setting cookies for domains like ".co.uk".
    // The domain of the requesting URL must likewise be a subdomain of the
    // cookie domain. This prevents us from setting cookies for entirely
    // unrelated domains.
    if (!isSubdomain(cookie.host, baseDomain) ||
        !isSubdomain(uri.host, cookie.host)) {
      return false;
    }

    // RFC2109 suggests that we may only add cookies for sub-domains 1-level
    // below us, but enforcing that would break the web, so we don't.
  }

  // An explicit domain was passed, so add a leading "." to make this a
  // domain cookie.
  cookie.host = "." + cookie.host;

  // We don't do any significant checking of path permissions. RFC2109
  // suggests we only allow sites to add cookies for sub-paths, similar to
  // same origin policy enforcement, but no-one implements this.

  return true;
};

const query = function* (detailsIn, props, context) {
  // Different callers want to filter on different properties. |props|
  // tells us which ones they're interested in.
  let details = {};
  props.forEach(property => {
    if (detailsIn[property] !== null) {
      details[property] = detailsIn[property];
    }
  });

  if ("domain" in details) {
    details.domain = details.domain.toLowerCase().replace(/^\./, "");
  }

  let userContextId = 0;
  let isPrivate = context.incognito;
  if (details.storeId) {
    if (!isValidCookieStoreId(details.storeId)) {
      return;
    }

    if (isDefaultCookieStoreId(details.storeId)) {
      isPrivate = false;
    } else if (isPrivateCookieStoreId(details.storeId)) {
      isPrivate = true;
    } else if (isContainerCookieStoreId(details.storeId)) {
      isPrivate = false;
      userContextId = getContainerForCookieStoreId(details.storeId);
      if (!userContextId) {
        return;
      }
    }
  }

  let storeId = DEFAULT_STORE;
  if (isPrivate) {
    storeId = PRIVATE_STORE;
  } else if ("storeId" in details) {
    storeId = details.storeId;
  }

  // We can use getCookiesFromHost for faster searching.
  let enumerator;
  let url;
  let originAttributes = {
    userContextId,
    privateBrowsingId: isPrivate ? 1 : 0,
  };
  if ("url" in details) {
    try {
      url = new URL(details.url);
      enumerator = Services.cookies.getCookiesFromHost(url.host, originAttributes);
    } catch (ex) {
      // This often happens for about: URLs
      return;
    }
  } else if ("domain" in details) {
    enumerator = Services.cookies.getCookiesFromHost(details.domain, originAttributes);
  } else {
    enumerator = Services.cookies.getCookiesWithOriginAttributes(JSON.stringify(originAttributes));
  }

  // Based on nsCookieService::GetCookieStringInternal
  function matches(cookie) {
    function domainMatches(host) {
      return cookie.rawHost == host || (cookie.isDomain && host.endsWith(cookie.host));
    }

    function pathMatches(path) {
      let cookiePath = cookie.path.replace(/\/$/, "");

      if (!path.startsWith(cookiePath)) {
        return false;
      }

      // path == cookiePath, but without the redundant string compare.
      if (path.length == cookiePath.length) {
        return true;
      }

      // URL path is a substring of the cookie path, so it matches if, and
      // only if, the next character is a path delimiter.
      return path[cookiePath.length] === "/";
    }

    // "Restricts the retrieved cookies to those that would match the given URL."
    if (url) {
      if (!domainMatches(url.host)) {
        return false;
      }

      if (cookie.isSecure && url.protocol != "https:") {
        return false;
      }

      if (!pathMatches(url.pathname)) {
        return false;
      }
    }

    if ("name" in details && details.name != cookie.name) {
      return false;
    }

    // "Restricts the retrieved cookies to those whose domains match or are subdomains of this one."
    if ("domain" in details && !isSubdomain(cookie.rawHost, details.domain)) {
      return false;
    }

    // "Restricts the retrieved cookies to those whose path exactly matches this string.""
    if ("path" in details && details.path != cookie.path) {
      return false;
    }

    if ("secure" in details && details.secure != cookie.isSecure) {
      return false;
    }

    if ("session" in details && details.session != cookie.isSession) {
      return false;
    }

    // Check that the extension has permissions for this host.
    if (!context.extension.whiteListedHosts.matchesCookie(cookie)) {
      return false;
    }

    return true;
  }

  for (const cookie of XPCOMUtils.IterSimpleEnumerator(enumerator, Ci.nsICookie2)) {
    if (matches(cookie)) {
      yield {cookie, isPrivate, storeId};
    }
  }
};

this.cookies = class extends ExtensionAPI {
  getAPI(context) {
    let {extension} = context;
    let self = {
      cookies: {
        get: function(details) {
          // FIXME: We don't sort by length of path and creation time.
          for (let cookie of query(details, ["url", "name", "storeId"], context)) {
            return Promise.resolve(convertCookie(cookie));
          }

          // Found no match.
          return Promise.resolve(null);
        },

        getAll: function(details) {
          let allowed = ["url", "name", "domain", "path", "secure", "session", "storeId"];
          let result = Array.from(query(details, allowed, context), convertCookie);

          return Promise.resolve(result);
        },

        set: function(details) {
          let uri = Services.io.newURI(details.url);

          let path;
          if (details.path !== null) {
            path = details.path;
          } else {
            // This interface essentially emulates the behavior of the
            // Set-Cookie header. In the case of an omitted path, the cookie
            // service uses the directory path of the requesting URL, ignoring
            // any filename or query parameters.
            path = uri.QueryInterface(Ci.nsIURL).directory;
          }

          let name = details.name !== null ? details.name : "";
          let value = details.value !== null ? details.value : "";
          let secure = details.secure !== null ? details.secure : false;
          let httpOnly = details.httpOnly !== null ? details.httpOnly : false;
          let isSession = details.expirationDate === null;
          let expiry = isSession ? Number.MAX_SAFE_INTEGER : details.expirationDate;
          let isPrivate = context.incognito;
          let userContextId = 0;
          if (isDefaultCookieStoreId(details.storeId)) {
            isPrivate = false;
          } else if (isPrivateCookieStoreId(details.storeId)) {
            isPrivate = true;
          } else if (isContainerCookieStoreId(details.storeId)) {
            let containerId = getContainerForCookieStoreId(details.storeId);
            if (containerId === null) {
              return Promise.reject({message: `Illegal storeId: ${details.storeId}`});
            }
            isPrivate = false;
            userContextId = containerId;
          } else if (details.storeId !== null) {
            return Promise.reject({message: "Unknown storeId"});
          }

          let cookieAttrs = {host: details.domain, path: path, isSecure: secure};
          if (!checkSetCookiePermissions(extension, uri, cookieAttrs)) {
            return Promise.reject({message: `Permission denied to set cookie ${JSON.stringify(details)}`});
          }

          let originAttributes = {
            userContextId,
            privateBrowsingId: isPrivate ? 1 : 0,
          };

          // The permission check may have modified the domain, so use
          // the new value instead.
          Services.cookies.add(cookieAttrs.host, path, name, value,
                               secure, httpOnly, isSession, expiry, originAttributes);

          return self.cookies.get(details);
        },

        remove: function(details) {
          for (let {cookie, storeId} of query(details, ["url", "name", "storeId"], context)) {
            Services.cookies.remove(cookie.host, cookie.name, cookie.path, false, cookie.originAttributes);

            // Todo: could there be multiple per subdomain?
            return Promise.resolve({
              url: details.url,
              name: details.name,
              storeId,
            });
          }

          return Promise.resolve(null);
        },

        getAllCookieStores: function() {
          let data = {};
          for (let tab of extension.tabManager.query()) {
            if (!(tab.cookieStoreId in data)) {
              data[tab.cookieStoreId] = [];
            }
            data[tab.cookieStoreId].push(tab.id);
          }

          let result = [];
          for (let key in data) {
            result.push({id: key, tabIds: data[key], incognito: key == PRIVATE_STORE});
          }
          return Promise.resolve(result);
        },

        onChanged: new EventManager(context, "cookies.onChanged", fire => {
          let observer = (subject, topic, data) => {
            let notify = (removed, cookie, cause) => {
              cookie.QueryInterface(Ci.nsICookie2);

              if (extension.whiteListedHosts.matchesCookie(cookie)) {
                fire.async({removed, cookie: convertCookie({cookie, isPrivate: topic == "private-cookie-changed"}), cause});
              }
            };

            // We do our best effort here to map the incompatible states.
            switch (data) {
              case "deleted":
                notify(true, subject, "explicit");
                break;
              case "added":
                notify(false, subject, "explicit");
                break;
              case "changed":
                notify(true, subject, "overwrite");
                notify(false, subject, "explicit");
                break;
              case "batch-deleted":
                subject.QueryInterface(Ci.nsIArray);
                for (let i = 0; i < subject.length; i++) {
                  let cookie = subject.queryElementAt(i, Ci.nsICookie2);
                  if (!cookie.isSession && cookie.expiry * 1000 <= Date.now()) {
                    notify(true, cookie, "expired");
                  } else {
                    notify(true, cookie, "evicted");
                  }
                }
                break;
            }
          };

          Services.obs.addObserver(observer, "cookie-changed");
          Services.obs.addObserver(observer, "private-cookie-changed");
          return () => {
            Services.obs.removeObserver(observer, "cookie-changed");
            Services.obs.removeObserver(observer, "private-cookie-changed");
          };
        }).api(),
      },
    };

    return self;
  }
};