import boto3
import botocore


class CodeCommitDifferencesResponse:
    """
    CodeCommitDifferencesResponse is the response object returned from our get_differences() function.
    It maps the JSON response to member variables of this class.
    """

    def __init__(self, json: dict):
        before_blob = json.get("beforeBlob", {})
        after_blob = json.get("afterBlob", {})

        self.before_blob_id = before_blob.get("blobId", "")
        self.before_blob_path = before_blob.get("path", "")
        self.after_blob_id = after_blob.get("blobId", "")
        self.after_blob_path = after_blob.get("path", "")
        self.change_type = json.get("changeType", "")


class CodeCommitPullRequestResponse:
    """
    CodeCommitPullRequestResponse is the response object returned from our get_pr() function.
    It maps the JSON response to member variables of this class.
    """

    def __init__(self, json: dict):
        self.title = json.get("title", "")
        self.description = json.get("description", "")

        self.targets = []
        for target in json.get("pullRequestTargets", []):
            self.targets.append(CodeCommitPullRequestResponse.CodeCommitPullRequestTarget(target))

    class CodeCommitPullRequestTarget:
        """
        CodeCommitPullRequestTarget is a subclass of CodeCommitPullRequestResponse that
        holds details about an individual target commit.
        """

        def __init__(self, json: dict):
            self.source_commit = json.get("sourceCommit", "")
            self.source_branch = json.get("sourceReference", "")
            self.destination_commit = json.get("destinationCommit", "")
            self.destination_branch = json.get("destinationReference", "")


class CodeCommitClient:
    """
    CodeCommitClient is a wrapper around the AWS boto3 SDK for the CodeCommit client
    """

    def __init__(self):
        self.boto_client = None

    def _connect_boto_client(self):
        try:
            self.boto_client = boto3.client("codecommit")
        except Exception as e:
            raise ValueError(f"Failed to connect to AWS CodeCommit: {e}")

    def get_differences(self, repo_name: int, destination_commit: str, source_commit: str):
        """
        Get the differences between two commits in CodeCommit.

        Args:
        - repo_name: Name of the repository
        - destination_commit: Commit hash you want to merge into (the "before" hash) (usually on the main or master branch)
        - source_commit: Commit hash of the code you are adding (the "after" branch)

        Returns:
        - List of CodeCommitDifferencesResponse objects

        Boto3 Documentation:
        - aws codecommit get-differences
        - https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/codecommit/client/get_differences.html
        """
        if self.boto_client is None:
            self._connect_boto_client()

        # The differences response from AWS is paginated, so we need to iterate through the pages to get all the differences.
        differences = []
        try:
            paginator = self.boto_client.get_paginator("get_differences")
            for page in paginator.paginate(
                repositoryName=repo_name,
                beforeCommitSpecifier=destination_commit,
                afterCommitSpecifier=source_commit,
            ):
                differences.extend(page.get("differences", []))
        except botocore.exceptions.ClientError as e:
            raise ValueError(f"Failed to retrieve differences from CodeCommit PR #{self.pr_num}") from e

        output = []
        for json in differences:
            output.append(CodeCommitDifferencesResponse(json))
        return output

    def get_file(self, repo_name: str, file_path: str, sha_hash: str, optional: bool = False):
        """
        Retrieve a file from CodeCommit.

        Args:
        - repo_name: Name of the repository
        - file_path: Path to the file you are retrieving
        - sha_hash: Commit hash of the file you are retrieving

        Returns:
        - File contents

        Boto3 Documentation:
        - aws codecommit get_file
        - https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/codecommit/client/get_file.html
        """
        if not file_path:
            return ""

        if self.boto_client is None:
            self._connect_boto_client()

        try:
            response = self.boto_client.get_file(repositoryName=repo_name, commitSpecifier=sha_hash, filePath=file_path)
        except botocore.exceptions.ClientError as e:
            # if the file does not exist, but is flagged as optional, then return an empty string
            if optional and e.response["Error"]["Code"] == 'FileDoesNotExistException':
                return ""
            raise ValueError(f"CodeCommit cannot retrieve file '{file_path}' from repository '{repo_name}'") from e
        except Exception as e:
            raise ValueError(f"CodeCommit cannot retrieve file '{file_path}' from repository '{repo_name}'") from e
        if "fileContent" not in response:
            raise ValueError(f"File content is empty for file: {file_path}")

        return response.get("fileContent", "")

    def get_pr(self, pr_number: int):
        """
        Get a information about a CodeCommit PR.

        Args:
        - pr_number: The PR number you are requesting

        Returns:
        - CodeCommitPullRequestResponse object

        Boto3 Documentation:
        - aws codecommit get_pull_request
        - https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/codecommit/client/get_pull_request.html
        """
        if self.boto_client is None:
            self._connect_boto_client()

        try:
            response = self.boto_client.get_pull_request(pullRequestId=str(pr_number))
        except botocore.exceptions.ClientError as e:
            if e.response["Error"]["Code"] == 'PullRequestDoesNotExistException':
                raise ValueError(f"CodeCommit cannot retrieve PR: PR number does not exist: {pr_number}") from e
            raise ValueError(f"CodeCommit cannot retrieve PR: {pr_number}: boto client error") from e
        except Exception as e:
            raise ValueError(f"CodeCommit cannot retrieve PR: {pr_number}") from e

        if "pullRequest" not in response:
            raise ValueError("CodeCommit PR number not found: {pr_number}")

        return CodeCommitPullRequestResponse(response.get("pullRequest", {}))

    def publish_description(self, pr_number: int, pr_title: str, pr_body: str):
        """
        Set the title and description on a pull request

        Args:
        - pr_number: the AWS CodeCommit pull request number
        - pr_title: title of the pull request
        - pr_body: body of the pull request

        Returns:
        - None

        Boto3 Documentation:
        - aws codecommit update_pull_request_title
        - https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/codecommit/client/update_pull_request_title.html
        - aws codecommit update_pull_request_description
        - https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/codecommit/client/update_pull_request_description.html
        """
        if self.boto_client is None:
            self._connect_boto_client()

        try:
            self.boto_client.update_pull_request_title(pullRequestId=str(pr_number), title=pr_title)
            self.boto_client.update_pull_request_description(pullRequestId=str(pr_number), description=pr_body)
        except botocore.exceptions.ClientError as e:
            if e.response["Error"]["Code"] == 'PullRequestDoesNotExistException':
                raise ValueError(f"PR number does not exist: {pr_number}") from e
            if e.response["Error"]["Code"] == 'InvalidTitleException':
                raise ValueError(f"Invalid title for PR number: {pr_number}") from e
            if e.response["Error"]["Code"] == 'InvalidDescriptionException':
                raise ValueError(f"Invalid description for PR number: {pr_number}") from e
            if e.response["Error"]["Code"] == 'PullRequestAlreadyClosedException':
                raise ValueError(f"PR is already closed: PR number: {pr_number}") from e
            raise ValueError(f"Boto3 client error calling publish_description") from e
        except Exception as e:
            raise ValueError(f"Error calling publish_description") from e

    def publish_comment(self, repo_name: str, pr_number: int, destination_commit: str, source_commit: str, comment: str):
        """
        Publish a comment to a pull request

        Args:
        - repo_name: name of the repository
        - pr_number: number of the pull request
        - destination_commit: The commit hash you want to merge into (the "before" hash) (usually on the main or master branch)
        - source_commit: The commit hash of the code you are adding (the "after" branch)
        - pr_comment: comment

        Returns:
        - None

        Boto3 Documentation:
        - aws codecommit post_comment_for_pull_request
        - https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/codecommit/client/post_comment_for_pull_request.html
        """
        if self.boto_client is None:
            self._connect_boto_client()

        try:
            self.boto_client.post_comment_for_pull_request(
                pullRequestId=str(pr_number),
                repositoryName=repo_name,
                beforeCommitId=destination_commit,
                afterCommitId=source_commit,
                content=comment,
            )
        except botocore.exceptions.ClientError as e:
            if e.response["Error"]["Code"] == 'RepositoryDoesNotExistException':
                raise ValueError(f"Repository does not exist: {repo_name}") from e
            if e.response["Error"]["Code"] == 'PullRequestDoesNotExistException':
                raise ValueError(f"PR number does not exist: {pr_number}") from e
            raise ValueError(f"Boto3 client error calling post_comment_for_pull_request") from e
        except Exception as e:
            raise ValueError(f"Error calling post_comment_for_pull_request") from e