"""Contains helper functions to compute checksums for LLVM checkouts.
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import logging
import os
import os.path
import sys


class LLVMProject(object):
  """An LLVM project with a descriptive name and a relative checkout path.
  """

  def __init__(self, name, relpath):
    self.name = name
    self.relpath = relpath

  def is_subproject(self, other_project):
    """ Check if self is checked out as a subdirectory of other_project.
    """
    return self.relpath.startswith(other_project.relpath)


def WalkProjectFiles(checkout_root, all_projects, project, visitor):
  """ Walk over all files inside a project without recursing into subprojects, '.git' and '.svn' subfolders.

    checkout_root: root of the LLVM checkout.
    all_projects: projects in the LLVM checkout.
    project: a project to walk the files of. Must be inside all_projects.
    visitor: a function called on each visited file.
  """
  assert project in all_projects

  ignored_paths = set()
  for other_project in all_projects:
    if other_project != project and other_project.is_subproject(project):
      ignored_paths.add(os.path.join(checkout_root, other_project.relpath))

  def raise_error(err):
    raise err

  project_root = os.path.join(checkout_root, project.relpath)
  for root, dirs, files in os.walk(project_root, onerror=raise_error):
    dirs[:] = [
        d for d in dirs
        if d != ".svn" and d != ".git" and
        os.path.join(root, d) not in ignored_paths
    ]
    for f in files:
      visitor(os.path.join(root, f))


def CreateLLVMProjects(single_tree_checkout):
  """Returns a list of LLVMProject instances, describing relative paths of a typical LLVM checkout.

  Args:
    single_tree_checkout:
      When True, relative paths for each project points to a typical single
        source tree checkout.
      When False, relative paths for each projects points to a separate
        directory. However, clang-tools-extra is an exception, its relative path
        will always be 'clang/tools/extra'.
  """
  # FIXME: cover all of llvm projects.

  # Projects that reside inside 'projects/' in a single source tree checkout.
  ORDINARY_PROJECTS = [
      "compiler-rt", "dragonegg", "libcxx", "libcxxabi", "libunwind",
      "parallel-libs", "test-suite"
  ]
  # Projects that reside inside 'tools/' in a single source tree checkout.
  TOOLS_PROJECTS = ["clang", "lld", "lldb"]

  if single_tree_checkout:
    projects = [LLVMProject("llvm", "")]
    projects += [
        LLVMProject(p, os.path.join("projects", p)) for p in ORDINARY_PROJECTS
    ]
    projects += [
        LLVMProject(p, os.path.join("tools", p)) for p in TOOLS_PROJECTS
    ]
    projects.append(
        LLVMProject("clang-tools-extra",
                    os.path.join("tools", "clang", "tools", "extra")))
  else:
    projects = [LLVMProject("llvm", "llvm")]
    projects += [LLVMProject(p, p) for p in ORDINARY_PROJECTS]
    projects += [LLVMProject(p, p) for p in TOOLS_PROJECTS]
    projects.append(
        LLVMProject("clang-tools-extra", os.path.join("clang", "tools",
                                                      "extra")))
  return projects