# Copyright 2023 Google LLC

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     https://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import typer
import pathlib
import re
import jinja2
from typing import Optional
from typing_extensions import Annotated
from .cli_utils import *
from .cli_constants import DEBUG


vars_app = typer.Typer()

INCLUDE_PATTERNS = [
    "*.yaml", "*.yml", "*.env", "*.tfvars", "*.tf", "*.sh"
]
EXCLUDE_PATTERNS = ["**/.terraform/**/*.*",
                    "**/node_modules/**/*.*", "**/.venv/**/*.*"]

# Replace a variable with a given text content.


def replace_var_to_template(var_name, text, custom_template=False):
  # Regex test: https://regex101.com/r/XtnJQI/4
  # match_pattern matches lines with sb-var anchor in the comment at the end.
  # For example:
  #   PROJECT_ID: 12345          # sb-var:project_id
  #   region = "us-central1" # sb-var:region
  match_pattern = f"(\\s*[\":=-][ ]*)(-[ ]*)?([\"\']?)([^\"^\'^\r^\n]*)([\"\']?)\\s*#\\s*sb-var:{var_name}"

  # output_pattern prints the jinja2 template for the specific variable name.
  # For example:
  #   PROJECT_ID: {{project_id}} # sb-var:project_id
  output_pattern = f"\\1\\2\\3{{{{{var_name}}}}}\\5 # sb-var:{var_name}"

  # In addition, if custom_template is true, the pattern will extend to the custom
  # template string at the end of the anchor. For example:
  #   BUCKET_NAME: my-project-bucket # sb-var:project_id:{{project_id}}-bucket
  if custom_template:
    match_pattern = match_pattern + ":(.*)"
    output_pattern = f"\\1\\2\\3\\6\\5 # sb-var:{var_name}:\\6"

  # Replace with regex pattern and returns new text and count of changes.
  text, count = re.subn(match_pattern, output_pattern, text)

  return (text, count)


def restore_template_in_comment(var_name, var_value, text):
  # Restore jinja2 variables in the custom content comment.
  match_pattern = f"(#\\s*sb-var:{var_name}:)(.*){var_value}(.*)"
  output_pattern = f"\\1\\2{{{{{var_name}}}}}\\3"

  text, count = re.subn(match_pattern, output_pattern, text)
  return (text, count)


def replace_var_to_value(var_name, var_value, text):
  overall_count = 0

  # Replace simple variable pattern with sb-var:var_name
  text, count = replace_var_to_template(var_name, text)
  overall_count += count

  # Replace custom-content variable pattern with sb-var:var_name:custom_template
  text, count = replace_var_to_template(var_name, text, custom_template=True)
  overall_count += count

  # Update variables using Jinja2
  jinja_env = jinja2.Environment()
  text = text.replace("# copier:raw", "# copier:raw{% raw %}")
  text = text.replace("# copier:endraw", "# copier:endraw{% endraw %}")
  template = jinja_env.from_string(text)

  # Set vars data for jinja
  data = {}
  data[var_name] = var_value

  # Apply variable values using Jinja2
  text = template.render(**data)

  # Restore vars to template in comment.
  text, count = restore_template_in_comment(var_name, var_value, text)

  return (text, overall_count)

# Apply a specific variable with a new value.


def apply_var_to_folder(solution_path, var_name, var_value):
  file_set = set()

  # Adding includes.
  for pattern in INCLUDE_PATTERNS:
    file_list = pathlib.Path(solution_path).rglob(f"{pattern}")
    file_set.update(set([str(x) for x in file_list]))

  # Removing excludes.
  for pattern in EXCLUDE_PATTERNS:
    file_list = pathlib.Path(solution_path).rglob(f"{pattern}")
    file_set = file_set - set([str(x) for x in file_list])

  modified_files_list = []
  for filename in list(file_set):
    if DEBUG:
      print(filename)

    with open(filename, "r") as file:
      # Replace variable
      filedata = file.read()
      filedata, count = replace_var_to_value(var_name, var_value, filedata)
      filedata = filedata + "\n"

      if count > 0:
        modified_files_list.append(filename)

      # If there's any changes, write back to the original file.
      if count > 0:
        with open(filename, "w") as file:
          file.write(filedata)

  return modified_files_list

# CLI command for `sb vars set <var_name> <var_value>`


@vars_app.command(name="set")
def set_var(
    var_name,
    var_value,
    solution_path: Annotated[Optional[str], typer.Argument()] = ".",
):
  validate_solution_folder(solution_path)
  print(f"Setting variable '{var_name}' to '{var_value}'...")

  # Update to the root sb.yaml
  root_st_yaml = read_yaml(f"{solution_path}/sb.yaml")
  global_variables = root_st_yaml.get("global_variables", {})
  global_variables[var_name] = var_value
  root_st_yaml["global_variables"] = global_variables
  write_yaml(f"{solution_path}/sb.yaml", root_st_yaml)

  # Apply vars to individual files
  filenames = apply_var_to_folder(solution_path, var_name, var_value)

  print_success(
      f"Complete. {len(filenames)} files updated.\n"
  )

# CLI command for `sb vars apply-all`


@vars_app.command(name="apply-all")
def apply_all(
    solution_path: Annotated[Optional[str], typer.Argument()] = ".",
):
  validate_solution_folder(solution_path)

  # Update to the root sb.yaml
  root_st_yaml = read_yaml(f"{solution_path}/sb.yaml")
  global_variables = root_st_yaml.get("global_variables", {})
  filenames = []

  for var_name, var_value in global_variables.items():
    filenames += apply_var_to_folder(solution_path, var_name, var_value)

  print_success(
      f"Complete. {len(filenames)} files updated.\n"
  )