import os
import subprocess
from datetime import datetime

"""
Oras class

This class should provide the basic methods required by the command line
interface.
"""
class Oras:
    """
    Oras class
    """
    def __init__(self, image: str, tag: str):
        self.image = image
        self.tag = tag
        self.registry_username = os.environ.get("REGISTRY_USERNAME", None)
        self.registry_password = os.environ.get("REGISTRY_PASSWORD", None)

    def check_downloaded_file(self):
        cwd = os.getcwd()
        result = f"{cwd}/result.cdx"
        print(f"Checking if '{result}' exists...")
        return os.path.isfile(result)

    def clean_downloaded_file(self):
        cwd = os.getcwd()
        result = f"{cwd}/result.cdx"
        print(f"Removing '{result}'...")
        try:
            os.remove(result)
        except FileNotFoundError:
            return self.error()

        return self.success()

    def os_system(self, base: str, suffix: str):
        extra_vars = None
        if self.registry_username and self.registry_password:
            extra_vars = f"--username {self.registry_username} --password {self.registry_password}"

        cmd = f"{base} {suffix}"
        if extra_vars:
            cmd = f"{base} {extra_vars} {suffix}"
        cmd_result = subprocess.run(cmd.split(" "), stdout=subprocess.PIPE)
        return cmd_result.stdout.decode("utf-8"), cmd_result.returncode

    def get_attached_cdx_digest(self):
        base = "oras discover"
        suffix = f"--artifact-type application/json {self.image}:{self.tag}"

        print(f"Retrieving attached digest {self.image}:{self.tag}...")
        cmd_reply, return_code = self.os_system(base, suffix)

        if return_code != 0:
            return False

        return cmd_reply.split("\n")[-2].split(" ")[-1]

    def get_attached_file(self):
        base = "oras pull"
        digest = self.get_attached_cdx_digest()
        suffix = f"{self.image}:@{digest}"

        print(f"Downloading attached file {self.image}:@{digest}...")
        cmd_reply, _ = self.os_system(base, suffix)

        return cmd_reply

    def post_attached_file(self, git_tag: str = None):
        if not git_tag:
            print("Error: Please provide a git tag...")
            return self.error()
        base = "oras attach"
        suffix = f"--artifact-type application/json {self.image}:{self.tag} result.cdx"

        dt = datetime.now()

        annotations = f"-a 'org.opencontainers.trivy.created={dt.isoformat()}"
        annotations = f"{annotations} -a 'org.opencontainers.trivy.status=Passed"
        annotations = f"{annotations} -a 'org.opencontainers.trivy.tag={git_tag}"

        base = f"{base} {annotations}"

        print(f"Attaching result report file to digest {self.image}:{self.tag}...")
        cmd_reply, return_code = self.os_system(base, suffix)

        if return_code != 0:
            return self.error()
        return self.success()

    def check_scan_report(self):
        get_result = self.get_attached_file()
        if not get_result:
            return self.error()
        if not self.check_downloaded_file():
            return self.error()
        else:
            print("Results file found...")

        self.clean_downloaded_file()
        return self.success()

    def success(self):
        return True

    def error(self):
        return False