/*
 * Copyright (C) 2009-2012 the libgit2 contributors
 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */

#include <assert.h>

#include "git2/checkout.h"
#include "git2/repository.h"
#include "git2/refs.h"
#include "git2/tree.h"
#include "git2/commit.h"
#include "git2/blob.h"

#include "common.h"
#include "refs.h"
#include "buffer.h"
#include "repository.h"
#include "filter.h"

GIT_BEGIN_DECL


static int get_head_tree(git_tree **out, git_repository *repo)
{
   int retcode = GIT_ERROR;
   git_reference *head = NULL;

   /* Dereference HEAD all the way to an OID ref */
   if (!git_reference_lookup_resolved(&head, repo, GIT_HEAD_FILE, -1)) {
      /* The OID should be a commit */
      git_object *commit;
      if (!git_object_lookup(&commit, repo,
                             git_reference_oid(head), GIT_OBJ_COMMIT)) {
         /* Get the tree */
         if (!git_commit_tree(out, (git_commit*)commit)) {
            retcode = 0;
         }
         git_object_free(commit);
      }
      git_reference_free(head);
   }

   return retcode;
}

typedef struct tree_walk_data
{
   git_indexer_stats *stats;
   git_repository *repo;
} tree_walk_data;


static int count_walker(const char *path, git_tree_entry *entry, void *payload)
{
   GIT_UNUSED(path);
   GIT_UNUSED(entry);
   ((tree_walk_data*)payload)->stats->total++;
   return 0;
}

static int apply_filters(git_buf *out,
                         git_vector *filters,
                         const void *data,
                         size_t len)
{
   int retcode = GIT_ERROR;

   git_buf_clear(out);

   if (!filters->length) {
      /* No filters to apply; just copy the result */
      git_buf_put(out, data, len);
      return 0;
   }

   git_buf origblob;
   git_buf_attach(&origblob, (char*)data, len);
   retcode = git_filters_apply(out, &origblob, filters);
   git_buf_detach(&origblob);

   return retcode;
}

static int blob_contents_to_file(git_repository *repo, git_buf *fnbuf, const git_oid *id, int mode)
{
   int retcode = GIT_ERROR;

   git_blob *blob;
   if (!git_blob_lookup(&blob, repo, id)) {
      const void *contents = git_blob_rawcontent(blob);
      size_t len = git_blob_rawsize(blob);
      git_vector filters = GIT_VECTOR_INIT;
      int filter_count;

      /* TODO: line-ending smudging */
      filter_count = git_filters_load(&filters, repo,
                                      git_buf_cstr(fnbuf),
                                      GIT_FILTER_TO_WORKTREE);
      printf("Got %d filters\n", filter_count);
      if (filter_count >= 0) {
         git_buf filteredblob = GIT_BUF_INIT;
         if (!apply_filters(&filteredblob, &filters, contents, len)) {
            int fd = git_futils_creat_withpath(git_buf_cstr(fnbuf),
                                               GIT_DIR_MODE, mode);
            if (fd >= 0) {
               retcode = (!p_write(fd, contents, len)) ? 0 : GIT_ERROR;
               p_close(fd);
            }
         }
      }

      git_blob_free(blob);
   }

   return retcode;
}

static int checkout_walker(const char *path, git_tree_entry *entry, void *payload)
{
   int retcode = 0;
   tree_walk_data *data = (tree_walk_data*)payload;
   int attr = git_tree_entry_attributes(entry);

   switch(git_tree_entry_type(entry)) {
   case GIT_OBJ_TREE:
      /* TODO: mkdir? */
      break;

   case GIT_OBJ_BLOB:
      {
         git_buf fnbuf = GIT_BUF_INIT;
         git_buf_join_n(&fnbuf, '/', 3,
                        git_repository_workdir(data->repo),
                        path,
                        git_tree_entry_name(entry));
         retcode = blob_contents_to_file(data->repo, &fnbuf, git_tree_entry_id(entry), attr);
         git_buf_free(&fnbuf);
      }
      break;

   default:
      retcode = -1;
      break;
   }

   data->stats->processed++;
   return retcode;
}

/* TODO
 * -> Line endings
 */
int git_checkout_force(git_repository *repo, git_indexer_stats *stats)
{
   int retcode = GIT_ERROR;
   git_indexer_stats dummy_stats;
   git_tree *tree;
   tree_walk_data payload;

   assert(repo);
   if (!stats) stats = &dummy_stats;

   stats->total = stats->processed = 0;
   payload.stats = stats;
   payload.repo = repo;

   if (!get_head_tree(&tree, repo)) {
      /* Count all the tree nodes for progress information */
      if (!git_tree_walk(tree, count_walker, GIT_TREEWALK_POST, &payload)) {
         /* Checkout the files */
         if (!git_tree_walk(tree, checkout_walker, GIT_TREEWALK_POST, &payload)) {
            retcode = 0;
         }
      }
      git_tree_free(tree);
   }

   return retcode;
}


GIT_END_DECL