import os
import shutil
import subprocess
import sys
import timeit
from copy import deepcopy
from typing import Literal, NotRequired, TypedDict

import requests
import yaml

# Get TMP_DIR variable from environment
TMP_DIR = os.path.join(os.environ.get("TMP_DIR", "/tmp"), "ohmyzsh")
# Relative path to dependencies.yml file
DEPS_YAML_FILE = ".github/dependencies.yml"
# Dry run flag
DRY_RUN = os.environ.get("DRY_RUN", "0") == "1"


class CodeTimer:
    def __init__(self, name=None):
        self.name = " '" + name + "'" if name else ""

    def __enter__(self):
        self.start = timeit.default_timer()

    def __exit__(self, exc_type, exc_value, traceback):
        self.took = (timeit.default_timer() - self.start) * 1000.0
        print("Code block" + self.name + " took: " + str(self.took) + " ms")


### YAML representation
def str_presenter(dumper, data):
    """
    Configures yaml for dumping multiline strings
    Ref: https://stackoverflow.com/a/33300001
    """
    if len(data.splitlines()) > 1:  # check for multiline string
        return dumper.represent_scalar("tag:yaml.org,2002:str", data, style="|")
    return dumper.represent_scalar("tag:yaml.org,2002:str", data)


yaml.add_representer(str, str_presenter)
yaml.representer.SafeRepresenter.add_representer(str, str_presenter)


# Types
class DependencyDict(TypedDict):
    repo: str
    branch: str
    version: str
    precopy: NotRequired[str]
    postcopy: NotRequired[str]


class DependencyYAML(TypedDict):
    dependencies: dict[str, DependencyDict]


class UpdateStatusFalse(TypedDict):
    has_updates: Literal[False]


class UpdateStatusTrue(TypedDict):
    has_updates: Literal[True]
    version: str
    compare_url: str
    head_ref: str
    head_url: str


class CommandRunner:
    class Exception(Exception):
        def __init__(self, message, returncode, stage, stdout, stderr):
            super().__init__(message)
            self.returncode = returncode
            self.stage = stage
            self.stdout = stdout
            self.stderr = stderr

    @staticmethod
    def run_or_fail(command: list[str], stage: str, *args, **kwargs):
        if DRY_RUN and command[0] == "gh":
            command.insert(0, "echo")

        result = subprocess.run(command, *args, capture_output=True, **kwargs)

        if result.returncode != 0:
            raise CommandRunner.Exception(
                f"{stage} command failed with exit code {result.returncode}",
                returncode=result.returncode,
                stage=stage,
                stdout=result.stdout.decode("utf-8"),
                stderr=result.stderr.decode("utf-8"),
            )

        return result


class DependencyStore:
    store: DependencyYAML = {"dependencies": {}}

    @staticmethod
    def set(data: DependencyYAML):
        DependencyStore.store = data

    @staticmethod
    def update_dependency_version(path: str, version: str) -> DependencyYAML:
        with CodeTimer(f"store deepcopy: {path}"):
            store_copy = deepcopy(DependencyStore.store)

        dependency = store_copy["dependencies"].get(path)
        if dependency is None:
            raise ValueError(f"Dependency {path} {version} not found")
        dependency["version"] = version
        store_copy["dependencies"][path] = dependency

        return store_copy

    @staticmethod
    def write_store(file: str, data: DependencyYAML):
        with open(file, "w") as yaml_file:
            yaml.safe_dump(data, yaml_file, sort_keys=False)


class Dependency:
    def __init__(self, path: str, values: DependencyDict):
        self.path = path
        self.values = values

        self.name: str = ""
        self.desc: str = ""
        self.kind: str = ""

        match path.split("/"):
            case ["plugins", name]:
                self.name = name
                self.kind = "plugin"
                self.desc = f"{name} plugin"
            case ["themes", name]:
                self.name = name.replace(".zsh-theme", "")
                self.kind = "theme"
                self.desc = f"{self.name} theme"
            case _:
                self.name = self.desc = path

    def __str__(self):
        output: str = ""
        for key in DependencyDict.__dict__["__annotations__"].keys():
            if key not in self.values:
                output += f"{key}: None\n"
                continue

            value = self.values[key]
            if "\n" not in value:
                output += f"{key}: {value}\n"
            else:
                output += f"{key}:\n  "
                output += value.replace("\n", "\n  ", value.count("\n") - 1)
        return output

    def update_or_notify(self):
        # Print dependency settings
        print(f"Processing {self.desc}...", file=sys.stderr)
        print(self, file=sys.stderr)

        # Check for updates
        repo = self.values["repo"]
        remote_branch = self.values["branch"]
        version = self.values["version"]
        is_tag = version.startswith("tag:")

        try:
            with CodeTimer(f"update check: {repo}"):
                if is_tag:
                    status = GitHub.check_newer_tag(repo, version.replace("tag:", ""))
                else:
                    status = GitHub.check_updates(repo, remote_branch, version)

            if status["has_updates"] is True:
                short_sha = status["head_ref"][:8]
                new_version = status["version"] if is_tag else short_sha

                try:
                    # Create new branch
                    branch = Git.create_branch(self.path, new_version)

                    # Update dependencies.yml file
                    self.__update_yaml(
                        f"tag:{new_version}" if is_tag else status["version"]
                    )

                    # Update dependency files
                    self.__apply_upstream_changes()

                    # Add all changes and commit
                    Git.add_and_commit(self.name, short_sha)

                    # Push changes to remote
                    Git.push(branch)

                    # Create GitHub PR
                    GitHub.create_pr(
                        branch,
                        f"feat({self.name}): update to version {new_version}",
                        f"""## Description

Update for **{self.desc}**: update to version [{new_version}]({status['head_url']}).
Check out the [list of changes]({status['compare_url']}).
""",
                    )

                    # Clean up repository
                    Git.clean_repo()
                except (CommandRunner.Exception, shutil.Error) as e:
                    # Handle exception on automatic update
                    match type(e):
                        case CommandRunner.Exception:
                            # Print error message
                            print(
                                f"Error running {e.stage} command: {e.returncode}",  # pyright: ignore[reportAttributeAccessIssue]
                                file=sys.stderr,
                            )
                            print(e.stderr, file=sys.stderr)  # pyright: ignore[reportAttributeAccessIssue]
                        case shutil.Error:
                            print(f"Error copying files: {e}", file=sys.stderr)

                    try:
                        Git.clean_repo()
                    except CommandRunner.Exception as e:
                        print(
                            f"Error reverting repository to clean state: {e}",
                            file=sys.stderr,
                        )
                        sys.exit(1)

                    # Create a GitHub issue to notify maintainer
                    title = f"{self.path}: update to {new_version}"
                    body = f"""## Description

There is a new version of `{self.name}` {self.kind} available.

New version: [{new_version}]({status['head_url']})
Check out the [list of changes]({status['compare_url']}).
"""

                    print("Creating GitHub issue", file=sys.stderr)
                    print(f"{title}\n\n{body}", file=sys.stderr)
                    GitHub.create_issue(title, body)
        except Exception as e:
            print(e, file=sys.stderr)

    def __update_yaml(self, new_version: str) -> None:
        dep_yaml = DependencyStore.update_dependency_version(self.path, new_version)
        DependencyStore.write_store(DEPS_YAML_FILE, dep_yaml)

    def __apply_upstream_changes(self) -> None:
        # Patterns to ignore in copying files from upstream repo
        GLOBAL_IGNORE = [".git", ".github", ".gitignore"]

        path = os.path.abspath(self.path)
        precopy = self.values.get("precopy")
        postcopy = self.values.get("postcopy")

        repo = self.values["repo"]
        branch = self.values["branch"]
        remote_url = f"https://github.com/{repo}.git"
        repo_dir = os.path.join(TMP_DIR, repo)

        # Clone repository
        Git.clone(remote_url, branch, repo_dir, reclone=True)

        # Run precopy on tmp repo
        if precopy is not None:
            print("Running precopy script:", end="\n  ", file=sys.stderr)
            print(
                precopy.replace("\n", "\n  ", precopy.count("\n") - 1), file=sys.stderr
            )
            CommandRunner.run_or_fail(
                ["bash", "-c", precopy], cwd=repo_dir, stage="Precopy"
            )

        # Copy files from upstream repo
        print(f"Copying files from {repo_dir} to {path}", file=sys.stderr)
        shutil.copytree(
            repo_dir,
            path,
            dirs_exist_ok=True,
            ignore=shutil.ignore_patterns(*GLOBAL_IGNORE),
        )

        # Run postcopy on our repository
        if postcopy is not None:
            print("Running postcopy script:", end="\n  ", file=sys.stderr)
            print(
                postcopy.replace("\n", "\n  ", postcopy.count("\n") - 1),
                file=sys.stderr,
            )
            CommandRunner.run_or_fail(
                ["bash", "-c", postcopy], cwd=path, stage="Postcopy"
            )


class Git:
    default_branch = "master"

    @staticmethod
    def clone(remote_url: str, branch: str, repo_dir: str, reclone=False):
        # If repo needs to be fresh
        if reclone and os.path.exists(repo_dir):
            shutil.rmtree(repo_dir)

        # Clone repo in tmp directory and checkout branch
        if not os.path.exists(repo_dir):
            print(
                f"Cloning {remote_url} to {repo_dir} and checking out {branch}",
                file=sys.stderr,
            )
            CommandRunner.run_or_fail(
                ["git", "clone", "--depth=1", "-b", branch, remote_url, repo_dir],
                stage="Clone",
            )

    @staticmethod
    def create_branch(path: str, version: str):
        # Get current branch name
        result = CommandRunner.run_or_fail(
            ["git", "rev-parse", "--abbrev-ref", "HEAD"], stage="GetDefaultBranch"
        )
        Git.default_branch = result.stdout.decode("utf-8").strip()

        # Create new branch and return created branch name
        branch_name = f"update/{path}/{version}"
        CommandRunner.run_or_fail(
            ["git", "checkout", "-b", branch_name], stage="CreateBranch"
        )
        return branch_name

    @staticmethod
    def add_and_commit(scope: str, version: str):
        user_name = os.environ.get("GIT_APP_NAME")
        user_email = os.environ.get("GIT_APP_EMAIL")

        # Add all files to git staging
        CommandRunner.run_or_fail(["git", "add", "-A", "-v"], stage="AddFiles")

        # Reset environment and git config
        clean_env = os.environ.copy()
        clean_env["LANG"] = "C.UTF-8"
        clean_env["GIT_CONFIG_GLOBAL"] = "/dev/null"
        clean_env["GIT_CONFIG_NOSYSTEM"] = "1"

        # Commit with settings above
        CommandRunner.run_or_fail(
            [
                "git",
                "-c",
                f"user.name={user_name}",
                "-c",
                f"user.email={user_email}",
                "commit",
                "-m",
                f"feat({scope}): update to {version}",
            ],
            stage="CreateCommit",
            env=clean_env,
        )

    @staticmethod
    def push(branch: str):
        CommandRunner.run_or_fail(
            ["git", "push", "-u", "origin", branch], stage="PushBranch"
        )

    @staticmethod
    def clean_repo():
        CommandRunner.run_or_fail(
            ["git", "reset", "--hard", "HEAD"], stage="ResetRepository"
        )
        CommandRunner.run_or_fail(
            ["git", "checkout", Git.default_branch], stage="CheckoutDefaultBranch"
        )


class GitHub:
    @staticmethod
    def check_newer_tag(repo, current_tag) -> UpdateStatusFalse | UpdateStatusTrue:
        # GET /repos/:owner/:repo/git/refs/tags
        url = f"https://api.github.com/repos/{repo}/git/refs/tags"

        # Send a GET request to the GitHub API
        response = requests.get(url)

        # If the request was successful
        if response.status_code == 200:
            # Parse the JSON response
            data = response.json()

            if len(data) == 0:
                return {
                    "has_updates": False,
                }

            latest_ref = data[-1]
            latest_tag = latest_ref["ref"].replace("refs/tags/", "")

            if latest_tag == current_tag:
                return {
                    "has_updates": False,
                }

            return {
                "has_updates": True,
                "version": latest_tag,
                "compare_url": f"https://github.com/{repo}/compare/{current_tag}...{latest_tag}",
                "head_ref": latest_ref["object"]["sha"],
                "head_url": f"https://github.com/{repo}/releases/tag/{latest_tag}",
            }
        else:
            # If the request was not successful, raise an exception
            raise Exception(
                f"GitHub API request failed with status code {response.status_code}: {response.json()}"
            )

    @staticmethod
    def check_updates(repo, branch, version) -> UpdateStatusFalse | UpdateStatusTrue:
        # TODO: add support for semver updating (based on tags)
        # Check if upstream github repo has a new version
        # GitHub API URL for comparing two commits
        url = f"https://api.github.com/repos/{repo}/compare/{version}...{branch}"

        # Send a GET request to the GitHub API
        response = requests.get(url)

        # If the request was successful
        if response.status_code == 200:
            # Parse the JSON response
            data = response.json()

            # If the base is behind the head, there is a newer version
            has_updates = data["status"] != "identical"

            if not has_updates:
                return {
                    "has_updates": False,
                }

            return {
                "has_updates": data["status"] != "identical",
                "version": data["commits"][-1]["sha"],
                "compare_url": data["permalink_url"],
                "head_ref": data["commits"][-1]["sha"],
                "head_url": data["commits"][-1]["html_url"],
            }
        else:
            # If the request was not successful, raise an exception
            raise Exception(
                f"GitHub API request failed with status code {response.status_code}: {response.json()}"
            )

    @staticmethod
    def create_issue(title: str, body: str) -> None:
        cmd = ["gh", "issue", "create", "-t", title, "-b", body]
        CommandRunner.run_or_fail(cmd, stage="CreateIssue")

    @staticmethod
    def create_pr(branch: str, title: str, body: str) -> None:
        cmd = [
            "gh",
            "pr",
            "create",
            "-B",
            Git.default_branch,
            "-H",
            branch,
            "-t",
            title,
            "-b",
            body,
        ]
        CommandRunner.run_or_fail(cmd, stage="CreatePullRequest")


def main():
    # Load the YAML file
    with open(DEPS_YAML_FILE, "r") as yaml_file:
        data: DependencyYAML = yaml.safe_load(yaml_file)

    if "dependencies" not in data:
        raise Exception("dependencies.yml not properly formatted")

    # Cache YAML version
    DependencyStore.set(data)

    dependencies = data["dependencies"]
    for path in dependencies:
        dependency = Dependency(path, dependencies[path])
        dependency.update_or_notify()


if __name__ == "__main__":
    main()