import argparse
import os
import yaml


def lint(filename):

    print("#", filename)
    with open(filename) as file:
        workflow = yaml.load(file, Loader=yaml.FullLoader)

        # Check for 'name' key for the workflow.
        if 'name' not in workflow:
            print("- Name key missing for workflow.")
        # Check for 'name' value to be capitalized in workflow.
        elif not workflow['name'][0].isupper():
            print(
                "- Name value for workflow is not capitalized. [" + workflow['name'] + "]")

        # Loop through jobs in workflow.
        if 'jobs' in workflow:
            jobs = workflow['jobs']
            for job_key in jobs:
                job = jobs[job_key]

                # Check for 'name' key for job.
                if 'name' not in job:
                    print("- Name key missing for job key '" + job_key + "'.")
                # Check for 'name' value to be capitallized in job.
                elif not job['name'][0].isupper():
                    print("- Name value of job key '" +
                          job_key + "' is not capitalized. [" + job['name'] + "]")

                # If the job has environment variables defined, then make sure they start with an underscore.
                if 'env' in job:
                    for k in job['env'].keys():
                        if k[0] != '_':
                            print("- Environment variable '" + k + "' of job key '" +
                                  job_key + "' does not start with an underscore.")

                # Loop through steps in job.
                steps = job['steps']
                for i, step in enumerate(steps, start=1):
                    # Check for 'name' key for step.
                    if 'name' not in step:
                        print("- Name key missing for step " + str(i) +
                              " of job key '" + job_key + "'.")
                    # Check for 'name' value to be capitalized in step.
                    elif not step['name'][0].isupper():
                        print("- Name value in step " + str(i) +
                              " of job key '" + job_key + "' is not capitalized. [" + step['name'] + "]")

                    # If the step has a 'uses' key, check value hash.
                    if 'uses' in step:
                        try:
                            _, hash = step['uses'].split('@')

                            # Check to make sure SHA1 hash is 40 characters.
                            if len(hash) != 40:
                                print("- Step " + str(i) + " of job key '" + job_key +
                                      "' does not have a valid action hash. (not 40 characters)")

                            # Attempts to convert the hash to a integer
                            # which will succeed if all characters are hexadecimal
                            try:
                                int(hash, 16)
                            except ValueError:
                                print("- Step " + str(i) + " of job key '" + job_key +
                                      "' does not have a valid action hash. (not all hexadecimal characters)")
                        except:
                            print("- Step " + str(i) + " of job key '" + job_key +
                                  "' does not have a valid action hash. (missing '@' character)")

    print()


def main():

    # Read arguments from command line.
    parser = argparse.ArgumentParser()
    parser.add_argument("input", help="file or directory input")
    args = parser.parse_args()

    # Set up list for files to lint.
    input_files = []

    # Check if argument is file, then append to input files.
    if os.path.isfile(args.input):
        input_files.append(args.input)
    # Check if argument is directory, then recursively add all *.yml and *.yaml files to input files.
    elif os.path.isdir(args.input):
        for subdir, dirs, files in os.walk(args.input):
            for filename in files:
                filepath = subdir + os.sep + filename

                if filepath.endswith(".yml") or filepath.endswith(".yaml"):
                    input_files.append(filepath)
    else:
        print("File/Directory does not exist, exiting.")

    for filename in input_files:
        lint(filename)


if __name__ == "__main__":
    main()