from __future__ import annotations

import os
import pathlib
import sys
import typing

import boto3
import botocore.client
import botocore.session
import rich.console
import rich.table
import rich.text
import typer

app = typer.Typer()
stdout = rich.console.Console()
stderr = rich.console.Console(stderr=True)
aws_profiles = boto3.session.Session().available_profiles


class SSMPath(pathlib.PurePosixPath):
    def __init__(self, *segments: str | os.PathLike):
        super().__init__("/", *segments)

    @staticmethod
    def parse(value: str) -> SSMPath:
        return SSMPath(value)


ProfileArg = typing.Annotated[str, typer.Argument(autocompletion=aws_profiles)]


def get_client(profile: str) -> botocore.client.BaseClient:
    try:
        session = boto3.Session(profile_name=profile)
        return session.client("ssm")
    except botocore.session.ProfileNotFound:
        stderr.print(f"Invalid profile '{profile}'", style="bold red")
        sys.exit(1)


def get_parameters(
    client: botocore.client.BaseClient, path: SSMPath, recursive: bool
) -> typing.Iterable[dict]:
    try:
        parameter = client.get_parameter(Name=str(path), WithDecryption=True)
        yield parameter.get("Parameter")
        return
    except client.exceptions.ParameterNotFound:
        pass
    results = client.get_paginator("get_parameters_by_path").paginate(
        Path=str(path),
        Recursive=recursive,
        WithDecryption=True,
    )
    for parameter in (
        result for chunk in results for result in chunk.get("Parameters")
    ):
        if parameter.get("Name"):
            yield parameter


@app.command()
def profiles() -> None:
    """List available AWS profiles."""
    for profile in aws_profiles:
        print(profile)


@app.command("ls")
def list_parameters(
    profile: ProfileArg,
    path: pathlib.Path,
    recursive: bool = True,
) -> None:
    """List parameters and their values at a requested PATH."""
    root = SSMPath(path)
    client = get_client(profile)
    console = rich.console.Console()
    table = rich.table.Table(
        "Name",
        "Value",
        "Description",
        "Type",
        title=f"{root} ({profile})",
    )
    try:
        for parameter in get_parameters(client, root, recursive):
            table.add_row(
                str(pathlib.Path(parameter["Name"]).relative_to(root)),
                parameter.get("Value"),
                parameter.get("Description"),
                parameter.get("Type"),
            )
    except client.exceptions.ClientError as e:
        stderr.print(str(e), style="bold red")
        sys.exit(1)
    console.print(table)


@app.command()
def set(
    profile: ProfileArg,
    path: str,
    value: str,
    secure: bool = False,
    overwrite: bool = False,
    description: typing.Annotated[str, typer.Option] = "",
) -> None:
    """Set a parameter at PATH to VALUE.

    If --secure is used, it will be stored as a SecureString.
    """
    client = get_client(profile)
    try:
        client.put_parameter(
            Name=str(SSMPath(path)),
            Value=value,
            Type="SecureString" if secure else "String",
            Overwrite=overwrite,
            Description=description,
        )
    except client.exceptions.ParameterAlreadyExists:
        stderr.print(
            "Parameter already exists; use --overwrite to replace it.",
            style="bold red",
        )
        sys.exit(1)


@app.command()
def unset(profile: ProfileArg, path: str) -> None:
    """Remove a parameter at PATH."""
    client = get_client(profile)
    try:
        client.delete_parameter(Name=str(SSMPath(path)))
    except client.exceptions.ParameterNotFound:
        stderr.print("Parameter not found", style="yellow")
        sys.exit(1)


@app.command("cp")
def copy_tree(
    source_profile: ProfileArg,
    source_path: str,
    dest_path: str,
    dest_profile: ProfileArg | None = None,
    replacement_pairs: list[str] = typer.Option([], "--replace", "-r"),
    recursive: bool = True,
) -> None:
    """Copy parameters from SRC_PATH to DEST_PATH."""

    def parse_replacements(values: list[str]) -> list[tuple[str, str]]:
        pairs: list[tuple[str, str]] = []
        for value in values:
            a, b = value.split("=", 1)
            pairs.append((a, b))
        return pairs

    replacements = parse_replacements(replacement_pairs)

    def replace(value: str) -> str:
        for old, new in replacements:
            value = value.replace(old, new)
        return value

    source = get_client(source_profile)
    destination = get_client(dest_profile or source_profile)
    sources = {
        str(pathlib.Path(p["Name"]).relative_to(SSMPath(source_path))): p
        for p in get_parameters(source, SSMPath(source_path), recursive=recursive)
    }
    targets = {
        str(pathlib.Path(p["Name"]).relative_to(SSMPath(dest_path))): p
        for p in get_parameters(destination, SSMPath(dest_path), recursive=recursive)
    }
    table = rich.table.Table("Path", "Old Value", "New Value")
    for name, param in sources.items():
        old = targets[name]["Value"] if name in targets else None
        new = replace(param["Value"])
        table.add_row(
            name,
            rich.text.Text(old, style="red")
            if old
            else rich.text.Text("Not defined", style="bright_black italic"),
            rich.text.Text(new, style="green"),
        )
    stdout.print(table)
    confirmed = typer.confirm("Are you sure you want to apply the above changes?")
    if not confirmed:
        stderr.print("No changes applied", style="yellow italic")
        sys.exit(1)
    for name, param in sources.items():
        new_name = str(SSMPath(dest_path) / pathlib.Path(name))
        stdout.print(f"Writing {new_name}...")
        destination.put_parameter(
            Name=new_name,
            Value=param["Value"],
            Type=param["Type"],
            Overwrite=True,
            Description=param.get("Description", ""),
        )


if __name__ == "__main__":
    app()