{ stdenv
, lib
, fetchurl
, fetchgit
, symlinkJoin

, tor
, tor-browser-unwrapped

# Extensions, common
, unzip
, zip

# HTTPS Everywhere
, git
, libxml2 # xmllint
, python27
, python27Packages
, rsync

# Customization
, extraPrefs ? ""
}:

let
  tor-browser-build_src = fetchgit {
    url = "https://git.torproject.org/builders/tor-browser-build.git";
    rev = "refs/tags/tbb-7.5a5-build5";
    sha256 = "0j37mqldj33fnzghxifvy6v8vdwkcz0i4z81prww64md5s8qcsa9";
  };

  # Each extension drv produces an output comprising an unpacked .xpi
  # named after the extension uuid, as it would appear under
  # `firefox/extensions'.
  firefoxExtensions = {
    https-everywhere = stdenv.mkDerivation rec {
      name = "https-everywhere-${version}";
      version = "5.2.21";

      extid = "https-everywhere-eff@eff.org";

      src = fetchgit {
        url = "https://git.torproject.org/https-everywhere.git";
        rev = "refs/tags/${version}";
        sha256 = "0z9madihh4b4z4blvfmh6w1hsv8afyi0x7b243nciq9r4w55xgfa";
      };

      nativeBuildInputs = [
        git
        libxml2 # xmllint
        python27
        python27Packages.lxml
        rsync
        unzip
        zip
      ];

      unpackPhase = ''
        cp -dR --no-preserve=mode "$src" src
        cd src
      '';

      # Beware: the build expects translations/ to be non-empty (which it
      # will be with submodules initialized).
      buildPhase = ''
        $shell ./makexpi.sh ${version} --no-recurse
      '';

      installPhase = ''
        mkdir $out
        unzip -d "$out/$extid" "pkg/https-everywhere-$version-eff.xpi"
      '';

      meta = {
        homepage = https://gitweb.torproject.org/https-everywhere.git/;
      };
    };

    noscript = stdenv.mkDerivation rec {
      name = "noscript-${version}";
      version = "5.0.10";

      extid = "{73a6fe31-595d-460b-a920-fcc0f8843232}";

      src = fetchurl {
        url = "https://secure.informaction.com/download/releases/noscript-${version}.xpi";
        sha256 = "18k5karbaj5mhd9cyjbqgik6044bw88rjalkh6anjanxbn503j6g";
      };

      nativeBuildInputs = [ unzip ];

      unpackPhase = ":";

      installPhase = ''
        mkdir $out
        unzip -d "$out/$extid" "$src"
      '';
    };

    torbutton = stdenv.mkDerivation rec {
      name = "torbutton-${version}";
      version = "1.9.8.1";

      extid = "torbutton@torproject.org";

      src = fetchgit {
        url = "https://git.torproject.org/torbutton.git";
        rev = "refs/tags/${version}";
        sha256 = "1amp0c9ky0a7fsa0bcbi6n6ginw7s2g3an4rj7kvc1lxmrcsm65l";
      };

      nativeBuildInputs = [ unzip zip ];

      unpackPhase = ''
        cp -dR --no-preserve=mode "$src" src
        cd src
      '';

      buildPhase = ''
        $shell ./makexpi.sh
      '';

      installPhase = ''
        mkdir $out
        unzip -d "$out/$extid" "pkg/torbutton-$version.xpi"
      '';

      meta = {
        homepage = https://gitweb.torproject.org/torbutton.git/;
      };
    };

    tor-launcher = stdenv.mkDerivation rec {
      name = "tor-launcher-${version}";
      version = "0.2.12.3";

      extid = "tor-launcher@torproject.org";

      src = fetchgit {
        url = "https://git.torproject.org/tor-launcher.git";
        rev = "refs/tags/${version}";
        sha256 = "0126x48pjiy2zm4l8jzhk70w24hviaz560ffp4lb9x0ar615bc9q";
      };

      nativeBuildInputs = [ unzip zip ];

      unpackPhase = ''
        cp -dR --no-preserve=mode "$src" src
        cd src
      '';

      buildPhase = ''
        make package
      '';

      installPhase = ''
        mkdir $out
        unzip -d "$out/$extid" "pkg/tor-launcher-$version.xpi"
      '';

      meta = {
        homepage = https://gitweb.torproject.org/tor-launcher.git/;
      };
    };
  };

  extensionsEnv = symlinkJoin {
    name = "tor-browser-extensions";
    paths = with firefoxExtensions; [ https-everywhere noscript torbutton tor-launcher ];
  };
in
stdenv.mkDerivation rec {
  name = "tor-browser-bundle-${version}";
  version = tor-browser-unwrapped.version;

  buildInputs = [ tor-browser-unwrapped tor ];

  unpackPhase = ":";

  buildPhase = ":";

  installPhase = ''
    TBBUILD=${tor-browser-build_src}/projects/tor-browser

    self=$out/lib/tor-browser
    mkdir -p $self && cd $self

    cp -dR ${tor-browser-unwrapped}/lib"/"*"/"* .
    chmod -R +w .

    # Prepare for autoconfig
    cat >defaults/pref/autoconfig.js <<EOF
    pref("general.config.filename", "mozilla.cfg");
    pref("general.config.obscure_value", 0);
    EOF

    # Hardcoded configuration
    cat >mozilla.cfg <<EOF
    // First line must be a comment

    // Always update via Nixpkgs
    lockPref("app.update.auto", false);
    lockPref("app.update.enabled", false);
    lockPref("extensions.update.autoUpdateDefault", false);
    lockPref("extensions.update.enabled", false);
    lockPref("extensions.torbutton.versioncheck_enabled", false);

    // Where to find the Nixpkgs tor executable & config
    lockPref("extensions.torlauncher.tor_path", "${tor}/bin/tor");
    lockPref("extensions.torlauncher.torrc-defaults_path", "$self/torrc-defaults");

    // Captures store paths
    clearPref("extensions.xpiState");

    // Insist on using IPC for communicating with Tor
    //
    // Defaults to $XDG_RUNTIME_DIR/Tor/{socks,control}.socket
    lockPref("extensions.torlauncher.control_port_use_ipc", true);
    lockPref("extensions.torlauncher.socks_port_use_ipc", true);

    // User customization
    ${extraPrefs}
    EOF

    # Preload extensions
    # XXX: the fact that ln -s env browser/extensions fails, symlinkJoin seems a little redundant ...
    ln -s -t browser/extensions ${extensionsEnv}"/"*

    # Copy bundle data
    cat \
      $TBBUILD/Bundle-Data/linux/Data/Tor/torrc-defaults \
      $TBBUILD/Bundle-Data/PTConfigs/linux/torrc-defaults-appendix \
      >> torrc-defaults

    cat \
      $TBBUILD/Bundle-Data/linux/Data/Browser/profile.default/preferences/extension-overrides.js \
      $TBBUILD/Bundle-Data/PTConfigs/bridge_prefs.js >> defaults/pref/extension-overrides.js \
      >> defaults/pref/extension-overrides.js

    # Generate a suitable wrapper
    mkdir -p $out/bin
    cat >$out/bin/tor-browser <<EOF
    #! ${stdenv.shell} -e

    THE_HOME=\$HOME
    TBB_HOME=\''${TBB_HOME:-\''${XDG_DATA_HOME:-$HOME/.local/share}/tor-browser}
    mkdir -p "\$TBB_HOME"

    HOME=\$TBB_HOME
    cd "\$HOME"

    exec $self/firefox -no-remote about:tor
    EOF
    chmod +x $out/bin/tor-browser
  '';

  meta = with stdenv.lib; {
    description = "An unofficial version of the tor browser bundle, built from source";
    homepage = https://torproject.org/;
    license = licenses.unfreeRedistributable; # TODO: check this
    platforms = [ "x86_64-linux" ];
    hydraPlatforms = [ ];
    maintainers = with maintainers; [ joachifm ];
  };
}