// This provides symbolic names for the octal modes used by git trees.
var modes = require('js-git/lib/modes');

// Create a repo by creating a plain object.
var repo = {};

// This provides an in-memory storage backend that provides the following APIs:
// - saveAs(type, value) => hash
// - loadAs(type, hash) => hash
// - saveRaw(hash, binary) =>
// - loadRaw(hash) => binary
require('js-git/mixins/mem-db')(repo);

// This adds a high-level API for creating multiple git objects by path.
// - createTree(entries) => hash
require('js-git/mixins/create-tree')(repo);

// This provides extra methods for dealing with packfile streams.
// It depends on
// - unpack(packStream, opts) => hashes
// - pack(hashes, opts) => packStream
require('js-git/mixins/pack-ops')(repo);

// This adds in walker algorithms for quickly walking history or a tree.
// - logWalk(ref|hash) => stream<commit>
// - treeWalk(hash) => stream<object>
require('js-git/mixins/walkers')(repo);

// This combines parallel requests for the same resource for effeciency under load.
require('js-git/mixins/read-combiner')(repo);

// This makes the object interface less strict.  See it's docs for details
require('js-git/mixins/formats')(repo);

var run = require('gen-run');

run(function*() {
 // Blocking logic goes here.  You can use yield
 var result = yield someAction(withArgs);
 // The generator pauses at yield and resumes when the data is available.
 // The rest of your process is not blocked, just this generator body.
 // If there was an error, it will throw into this generator.
});

someAction(withArgs, function (err, value) {
  if (err) return handleMyError(err);
  // do something with value
});

// The function would be implemented to support both style like this.
function someAction(arg, callback) {
  if (!callback) return someAction.bind(this, arg);
  // We now have callback and arg
}

  // First we create a blob from a string.  The `formats` mixin allows us to
  // use a string directly instead of having to pass in a binary buffer.
  var blobHash = yield repo.saveAs("blob", "Hello World\n");

  // Now we create a tree that is a folder containing the blob as `greeting.txt`
  var treeHash = yield repo.saveAs("tree", {
    "greeting.txt": { mode: modes.file, hash: blobHash }
  });

  // With that tree, we can create a commit.
  // Again the `formats` mixin allows us to omit details like committer, date,
  // and parents.  It assumes sane defaults for these.
  var commitHash = yield repo.saveAs("commit", {
    author: {
      name: "Tim Caswell",
      email: "tim@creationix.com"
    },
    tree: treeHash,
    message: "Test commit\n"
  });

// Reading the file "greeting.txt" from a commit.

// We first read the commit.
var commit = yield repo.loadAs("commit", commitHash);
// We then read the tree using `commit.tree`.
var tree = yield repo.loadAs("tree", commit.tree);
// We then read the file using the entry hash in the tree.
var file = yield repo.loadAs("blob", tree["greeting.txt"].hash);
// file is now a binary buffer.

// When you're sure the file contains unicode text, you can load it as text directly.
var fileAsText = yield repo.loadAs("text", blobHash);

// Also if you prefer array format, you can load a directory as an array.
var entries = yield repo.loadAs("array", treeHash);
entries.forEach(function (entry) {
  // entry contains {name, mode, hash}
});

// Create a log stream starting at the commit we just made.
// You could also use symbolic refs like `refs/heads/master` for repos that
// support them.
var logStream = yield repo.logWalk(commitHash);

// Looping through the stream is easy by repeatedly calling waiting on `read`.
var commit, object;
while (commit = yield logStream.read(), commit !== undefined) {

  console.log(commit);

  // We can also loop through all the files of each commit version.
  var treeStream = yield repo.treeWalk(commit.tree);
  while (object = yield treeStream.read(), object !== undefined) {
    console.log(object);
  }

}

// We wish to create a tree that contains `www/index.html` and `README.me` files.
// This will create these two blobs, create a tree for `www` and then create a
// tree for the root containing `README.md` and the newly created `www` tree.
var treeHash = yield repo.createTree({
  "www/index.html": {
    mode: modes.file,
    content: "<h1>Hello</h1>\n<p>This is an HTML page?</p>\n"
  },
  "README.md": {
    mode: modes.file,
    content: "# Sample repo\n\nThis is a sample\n"
  }
});

var changes = [
  {
    path: "www/index.html" // Leaving out mode means to delete the entry.
  },
  {
    path: "www/app.js", // Create a new file in the existing directory.
    mode: modes.file,
    content: "// this is a js file\n"
  }
];

// We need to use array form and specify the base tree hash as `base`.
changes.base = treeHash;

treeHash = yield repo.createTree(changes);