# This file originates from node2nix
 
 {stdenv, nodejs, python2, utillinux, libtool, runCommand, writeTextFile}:
 
 let
   python = if nodejs ? python then nodejs.python else python2;
 
   # Create a tar wrapper that filters all the 'Ignoring unknown extended header keyword' noise
   tarWrapper = runCommand "tarWrapper" {} ''
     mkdir -p $out/bin
 
     cat > $out/bin/tar <<EOF
     #! ${stdenv.shell} -e
     $(type -p tar) "\$@" --warning=no-unknown-keyword --delay-directory-restore
     EOF
 
     chmod +x $out/bin/tar
   '';
 
   # Function that generates a TGZ file from a NPM project
   buildNodeSourceDist =
     { name, version, src, ... }:
 
     stdenv.mkDerivation {
       name = "node-tarball-${name}-${version}";
       inherit src;
       buildInputs = [ nodejs ];
       buildPhase = ''
         export HOME=$TMPDIR
         tgzFile=$(npm pack | tail -n 1) # Hooks to the pack command will add output (https://docs.npmjs.com/misc/scripts)
       '';
       installPhase = ''
         mkdir -p $out/tarballs
         mv $tgzFile $out/tarballs
         mkdir -p $out/nix-support
         echo "file source-dist $out/tarballs/$tgzFile" >> $out/nix-support/hydra-build-products
       '';
     };
 
   includeDependencies = {dependencies}:
     stdenv.lib.optionalString (dependencies != [])
       (stdenv.lib.concatMapStrings (dependency:
         ''
           # Bundle the dependencies of the package
           mkdir -p node_modules
           cd node_modules
 
           # Only include dependencies if they don't exist. They may also be bundled in the package.
           if [ ! -e "${dependency.name}" ]
           then
               ${composePackage dependency}
           fi
 
           cd ..
         ''
       ) dependencies);
 
   # Recursively composes the dependencies of a package
   composePackage = { name, packageName, src, dependencies ? [], ... }@args:
     ''
       DIR=$(pwd)
       cd $TMPDIR
 
       unpackFile ${src}
 
       # Make the base dir in which the target dependency resides first
       mkdir -p "$(dirname "$DIR/${packageName}")"
 
       if [ -f "${src}" ]
       then
           # Figure out what directory has been unpacked
           packageDir="$(find . -maxdepth 1 -type d | tail -1)"
 
           # Restore write permissions to make building work
           find "$packageDir" -type d -exec chmod u+x {} \;
           chmod -R u+w "$packageDir"
 
           # Move the extracted tarball into the output folder
           mv "$packageDir" "$DIR/${packageName}"
       elif [ -d "${src}" ]
       then
           # Get a stripped name (without hash) of the source directory.
           # On old nixpkgs it's already set internally.
           if [ -z "$strippedName" ]
           then
               strippedName="$(stripHash ${src})"
           fi
 
           # Restore write permissions to make building work
           chmod -R u+w "$strippedName"
 
           # Move the extracted directory into the output folder
           mv "$strippedName" "$DIR/${packageName}"
       fi
 
       # Unset the stripped name to not confuse the next unpack step
       unset strippedName
 
       # Include the dependencies of the package
       cd "$DIR/${packageName}"
       ${includeDependencies { inherit dependencies; }}
       cd ..
       ${stdenv.lib.optionalString (builtins.substring 0 1 packageName == "@") "cd .."}
     '';
 
   pinpointDependencies = {dependencies, production}:
     let
       pinpointDependenciesFromPackageJSON = writeTextFile {
         name = "pinpointDependencies.js";
         text = ''
           var fs = require('fs');
           var path = require('path');
 
           function resolveDependencyVersion(location, name) {
               if(location == process.env['NIX_STORE']) {
                   return null;
               } else {
                   var dependencyPackageJSON = path.join(location, "node_modules", name, "package.json");
 
                   if(fs.existsSync(dependencyPackageJSON)) {
                       var dependencyPackageObj = JSON.parse(fs.readFileSync(dependencyPackageJSON));
 
                       if(dependencyPackageObj.name == name) {
                           return dependencyPackageObj.version;
                       }
                   } else {
                       return resolveDependencyVersion(path.resolve(location, ".."), name);
                   }
               }
           }
 
           function replaceDependencies(dependencies) {
               if(typeof dependencies == "object" && dependencies !== null) {
                   for(var dependency in dependencies) {
                       var resolvedVersion = resolveDependencyVersion(process.cwd(), dependency);
 
                       if(resolvedVersion === null) {
                           process.stderr.write("WARNING: cannot pinpoint dependency: "+dependency+", context: "+process.cwd()+"\n");
                       } else {
                           dependencies[dependency] = resolvedVersion;
                       }
                   }
               }
           }
 
           /* Read the package.json configuration */
           var packageObj = JSON.parse(fs.readFileSync('./package.json'));
 
           /* Pinpoint all dependencies */
           replaceDependencies(packageObj.dependencies);
           if(process.argv[2] == "development") {
               replaceDependencies(packageObj.devDependencies);
           }
           replaceDependencies(packageObj.optionalDependencies);
 
           /* Write the fixed package.json file */
           fs.writeFileSync("package.json", JSON.stringify(packageObj, null, 2));
         '';
       };
     in
     ''
       node ${pinpointDependenciesFromPackageJSON} ${if production then "production" else "development"}
 
       ${stdenv.lib.optionalString (dependencies != [])
         ''
           if [ -d node_modules ]
           then
               cd node_modules
               ${stdenv.lib.concatMapStrings (dependency: pinpointDependenciesOfPackage dependency) dependencies}
               cd ..
           fi
         ''}
     '';
 
   # Recursively traverses all dependencies of a package and pinpoints all
   # dependencies in the package.json file to the versions that are actually
   # being used.
 
   pinpointDependenciesOfPackage = { packageName, dependencies ? [], production ? true, ... }@args:
     ''
       if [ -d "${packageName}" ]
       then
           cd "${packageName}"
           ${pinpointDependencies { inherit dependencies production; }}
           cd ..
           ${stdenv.lib.optionalString (builtins.substring 0 1 packageName == "@") "cd .."}
       fi
     '';
 
   # Extract the Node.js source code which is used to compile packages with
   # native bindings
   nodeSources = runCommand "node-sources" {} ''
     tar --no-same-owner --no-same-permissions -xf ${nodejs.src}
     mv node-* $out
   '';
 
   # Script that adds _integrity fields to all package.json files to prevent NPM from consulting the cache (that is empty)
   addIntegrityFieldsScript = writeTextFile {
     name = "addintegrityfields.js";
     text = ''
       var fs = require('fs');
       var path = require('path');
 
       function augmentDependencies(baseDir, dependencies) {
           for(var dependencyName in dependencies) {
               var dependency = dependencies[dependencyName];
 
               // Open package.json and augment metadata fields
               var packageJSONDir = path.join(baseDir, "node_modules", dependencyName);
               var packageJSONPath = path.join(packageJSONDir, "package.json");
 
               if(fs.existsSync(packageJSONPath)) { // Only augment packages that exist. Sometimes we may have production installs in which development dependencies can be ignored
                   console.log("Adding metadata fields to: "+packageJSONPath);
                   var packageObj = JSON.parse(fs.readFileSync(packageJSONPath));
 
                   if(dependency.integrity) {
                       packageObj["_integrity"] = dependency.integrity;
                   } else {
                       packageObj["_integrity"] = "sha1-000000000000000000000000000="; // When no _integrity string has been provided (e.g. by Git dependencies), add a dummy one. It does not seem to harm and it bypasses downloads.
                   }
 
                   if(dependency.resolved) {
                       packageObj["_resolved"] = dependency.resolved; // Adopt the resolved property if one has been provided
                   } else {
                       packageObj["_resolved"] = dependency.version; // Set the resolved version to the version identifier. This prevents NPM from cloning Git repositories.
                   }
 
                   if(dependency.from !== undefined) { // Adopt from property if one has been provided
                       packageObj["_from"] = dependency.from;
                   }
 
                   fs.writeFileSync(packageJSONPath, JSON.stringify(packageObj, null, 2));
               }
 
               // Augment transitive dependencies
               if(dependency.dependencies !== undefined) {
                   augmentDependencies(packageJSONDir, dependency.dependencies);
               }
           }
       }
 
       if(fs.existsSync("./package-lock.json")) {
           var packageLock = JSON.parse(fs.readFileSync("./package-lock.json"));
 
           if(packageLock.lockfileVersion !== 1) {
              process.stderr.write("Sorry, I only understand lock file version 1!\n");
              process.exit(1);
           }
 
           if(packageLock.dependencies !== undefined) {
               augmentDependencies(".", packageLock.dependencies);
           }
       }
     '';
   };
 
   # Reconstructs a package-lock file from the node_modules/ folder structure and package.json files with dummy sha1 hashes
   reconstructPackageLock = writeTextFile {
     name = "addintegrityfields.js";
     text = ''
       var fs = require('fs');
       var path = require('path');
 
       var packageObj = JSON.parse(fs.readFileSync("package.json"));
 
       var lockObj = {
           name: packageObj.name,
           version: packageObj.version,
           lockfileVersion: 1,
           requires: true,
           dependencies: {}
       };
 
       function augmentPackageJSON(filePath, dependencies) {
           var packageJSON = path.join(filePath, "package.json");
           if(fs.existsSync(packageJSON)) {
               var packageObj = JSON.parse(fs.readFileSync(packageJSON));
               dependencies[packageObj.name] = {
                   version: packageObj.version,
                   integrity: "sha1-000000000000000000000000000=",
                   dependencies: {}
               };
               processDependencies(path.join(filePath, "node_modules"), dependencies[packageObj.name].dependencies);
           }
       }
 
       function processDependencies(dir, dependencies) {
           if(fs.existsSync(dir)) {
               var files = fs.readdirSync(dir);
 
               files.forEach(function(entry) {
                   var filePath = path.join(dir, entry);
                   var stats = fs.statSync(filePath);
 
                   if(stats.isDirectory()) {
                       if(entry.substr(0, 1) == "@") {
                           // When we encounter a namespace folder, augment all packages belonging to the scope
                           var pkgFiles = fs.readdirSync(filePath);
 
                           pkgFiles.forEach(function(entry) {
                               if(stats.isDirectory()) {
                                   var pkgFilePath = path.join(filePath, entry);
                                   augmentPackageJSON(pkgFilePath, dependencies);
                               }
                           });
                       } else {
                           augmentPackageJSON(filePath, dependencies);
                       }
                   }
               });
           }
       }
 
       processDependencies("node_modules", lockObj.dependencies);
 
       fs.writeFileSync("package-lock.json", JSON.stringify(lockObj, null, 2));
     '';
   };
 
   prepareAndInvokeNPM = {packageName, bypassCache, reconstructLock, npmFlags, production}:
     let
       forceOfflineFlag = if bypassCache then "--offline" else "--registry http://www.example.com";
     in
     ''
         # Pinpoint the versions of all dependencies to the ones that are actually being used
         echo "pinpointing versions of dependencies..."
         source $pinpointDependenciesScriptPath
 
         # Patch the shebangs of the bundled modules to prevent them from
         # calling executables outside the Nix store as much as possible
         patchShebangs .
 
         # Deploy the Node.js package by running npm install. Since the
         # dependencies have been provided already by ourselves, it should not
         # attempt to install them again, which is good, because we want to make
         # it Nix's responsibility. If it needs to install any dependencies
         # anyway (e.g. because the dependency parameters are
         # incomplete/incorrect), it fails.
         #
         # The other responsibilities of NPM are kept -- version checks, build
         # steps, postprocessing etc.
 
         export HOME=$TMPDIR
         cd "${packageName}"
         runHook preRebuild
 
         ${stdenv.lib.optionalString bypassCache ''
           ${stdenv.lib.optionalString reconstructLock ''
             if [ -f package-lock.json ]
             then
                 echo "WARNING: Reconstruct lock option enabled, but a lock file already exists!"
                 echo "This will most likely result in version mismatches! We will remove the lock file and regenerate it!"
                 rm package-lock.json
             else
                 echo "No package-lock.json file found, reconstructing..."
             fi
 
             node ${reconstructPackageLock}
           ''}
 
           node ${addIntegrityFieldsScript}
         ''}
 
         npm ${forceOfflineFlag} --nodedir=${nodeSources} ${npmFlags} ${stdenv.lib.optionalString production "--production"} rebuild
 
         if [ "$dontNpmInstall" != "1" ]
         then
             # NPM tries to download packages even when they already exist if npm-shrinkwrap is used.
             rm -f npm-shrinkwrap.json
 
             npm ${forceOfflineFlag} --nodedir=${nodeSources} ${npmFlags} ${stdenv.lib.optionalString production "--production"} install
         fi
     '';
 
   # Builds and composes an NPM package including all its dependencies
   buildNodePackage =
     { name
     , packageName
     , version
     , dependencies ? []
     , buildInputs ? []
     , production ? true
     , npmFlags ? ""
     , dontNpmInstall ? false
     , bypassCache ? false
     , reconstructLock ? false
     , preRebuild ? ""
     , dontStrip ? true
     , unpackPhase ? "true"
     , buildPhase ? "true"
     , ... }@args:
 
     let
       extraArgs = removeAttrs args [ "name" "dependencies" "buildInputs" "dontStrip" "dontNpmInstall" "preRebuild" "unpackPhase" "buildPhase" ];
     in
     stdenv.mkDerivation ({
       name = "node_${name}-${version}";
       buildInputs = [ tarWrapper python nodejs ]
         ++ stdenv.lib.optional (stdenv.isLinux) utillinux
         ++ stdenv.lib.optional (stdenv.isDarwin) libtool
         ++ buildInputs;
 
       inherit dontStrip; # Stripping may fail a build for some package deployments
       inherit dontNpmInstall preRebuild unpackPhase buildPhase;
 
       compositionScript = composePackage args;
       pinpointDependenciesScript = pinpointDependenciesOfPackage args;
 
       passAsFile = [ "compositionScript" "pinpointDependenciesScript" ];
 
       installPhase = ''
         # Create and enter a root node_modules/ folder
         mkdir -p $out/lib/node_modules
         cd $out/lib/node_modules
 
         # Compose the package and all its dependencies
         source $compositionScriptPath
 
         ${prepareAndInvokeNPM { inherit packageName bypassCache reconstructLock npmFlags production; }}
 
         # Create symlink to the deployed executable folder, if applicable
         if [ -d "$out/lib/node_modules/.bin" ]
         then
             ln -s $out/lib/node_modules/.bin $out/bin
         fi
 
         # Create symlinks to the deployed manual page folders, if applicable
         if [ -d "$out/lib/node_modules/${packageName}/man" ]
         then
             mkdir -p $out/share
             for dir in "$out/lib/node_modules/${packageName}/man/"*
             do
                 mkdir -p $out/share/man/$(basename "$dir")
                 for page in "$dir"/*
                 do
                     ln -s $page $out/share/man/$(basename "$dir")
                 done
             done
         fi
 
         # Run post install hook, if provided
         runHook postInstall
       '';
     } // extraArgs);
 
   # Builds a development shell
   buildNodeShell =
     { name
     , packageName
     , version
     , src
     , dependencies ? []
     , buildInputs ? []
     , production ? true
     , npmFlags ? ""
     , dontNpmInstall ? false
     , bypassCache ? false
     , reconstructLock ? false
     , dontStrip ? true
     , unpackPhase ? "true"
     , buildPhase ? "true"
     , ... }@args:
 
     let
       extraArgs = removeAttrs args [ "name" "dependencies" "buildInputs" ];
 
       nodeDependencies = stdenv.mkDerivation ({
         name = "node-dependencies-${name}-${version}";
 
         buildInputs = [ tarWrapper python nodejs ]
           ++ stdenv.lib.optional (stdenv.isLinux) utillinux
           ++ stdenv.lib.optional (stdenv.isDarwin) libtool
           ++ buildInputs;
 
         inherit dontStrip; # Stripping may fail a build for some package deployments
         inherit dontNpmInstall unpackPhase buildPhase;
 
         includeScript = includeDependencies { inherit dependencies; };
         pinpointDependenciesScript = pinpointDependenciesOfPackage args;
 
         passAsFile = [ "includeScript" "pinpointDependenciesScript" ];
 
         installPhase = ''
           mkdir -p $out/${packageName}
           cd $out/${packageName}
 
           source $includeScriptPath
 
           # Create fake package.json to make the npm commands work properly
           cp ${src}/package.json .
           chmod 644 package.json
           ${stdenv.lib.optionalString bypassCache ''
             if [ -f ${src}/package-lock.json ]
             then
                 cp ${src}/package-lock.json .
             fi
           ''}
 
           # Go to the parent folder to make sure that all packages are pinpointed
           cd ..
           ${stdenv.lib.optionalString (builtins.substring 0 1 packageName == "@") "cd .."}
 
           ${prepareAndInvokeNPM { inherit packageName bypassCache reconstructLock npmFlags production; }}
 
           # Expose the executables that were installed
           cd ..
           ${stdenv.lib.optionalString (builtins.substring 0 1 packageName == "@") "cd .."}
 
           mv ${packageName} lib
           ln -s $out/lib/node_modules/.bin $out/bin
         '';
       } // extraArgs);
     in
     stdenv.mkDerivation {
       name = "node-shell-${name}-${version}";
 
       buildInputs = [ python nodejs ] ++ stdenv.lib.optional (stdenv.isLinux) utillinux ++ buildInputs;
       buildCommand = ''
         mkdir -p $out/bin
         cat > $out/bin/shell <<EOF
         #! ${stdenv.shell} -e
         $shellHook
         exec ${stdenv.shell}
         EOF
         chmod +x $out/bin/shell
       '';
 
       # Provide the dependencies in a development shell through the NODE_PATH environment variable
       inherit nodeDependencies;
       shellHook = stdenv.lib.optionalString (dependencies != []) ''
         export NODE_PATH=$nodeDependencies/lib/node_modules
         export PATH="$nodeDependencies/bin:$PATH"
       '';
     };
 in
 {
   buildNodeSourceDist = stdenv.lib.makeOverridable buildNodeSourceDist;
   buildNodePackage = stdenv.lib.makeOverridable buildNodePackage;
   buildNodeShell = stdenv.lib.makeOverridable buildNodeShell;
 }