from __future__ import annotations

import os
import pwd
import shutil
import subprocess
from pathlib import Path

from .config import Settings


class AiderAgent:
    def __init__(self, settings: Settings) -> None:
        self.settings = settings

    def run(self, workspace: Path, task: str, files: tuple[str, ...] = ()) -> str:
        task_file = workspace / ".git" / "failure-task.txt"
        task_file.write_text(task)
        task_file.chmod(0o600)
        command = self.command(task_file, files)
        coder = pwd.getpwnam("coder")
        git_config = Path(coder.pw_dir) / ".gitconfig"
        git_config.write_text(
            "[user]\n\tname = LAI Automation Coder\n\temail = coder@localhost\n"
            f"[safe]\n\tdirectory = {workspace.resolve()}\n"
        )
        git_config.chmod(0o600)
        os.chown(git_config, coder.pw_uid, coder.pw_gid)
        os.chown(task_file, coder.pw_uid, coder.pw_gid)
        for path in workspace.rglob("*"):
            if ".git" not in path.parts:
                os.chown(path, coder.pw_uid, coder.pw_gid, follow_symlinks=False)
        os.chown(workspace, coder.pw_uid, coder.pw_gid, follow_symlinks=False)

        environment = {
            "HOME": coder.pw_dir,
            "PATH": os.environ.get("PATH", "/usr/local/bin:/usr/bin:/bin"),
        }
        for name in ("MISTRAL_API_KEY", "OPENAI_API_KEY", "ANTHROPIC_API_KEY"):
            if os.getenv(name):
                environment[name] = os.environ[name]

        def drop_privileges() -> None:
            os.setgroups([])
            os.setgid(coder.pw_gid)
            os.setuid(coder.pw_uid)

        try:
            result = subprocess.run(
                command,
                cwd=workspace,
                env=environment,
                text=True,
                capture_output=True,
                check=False,
                preexec_fn=drop_privileges,
                timeout=900,
            )
        finally:
            shutil.rmtree(workspace / ".aider.tags.cache.v4", ignore_errors=True)
            for artifact in (".aider.chat.history.md", ".aider.input.history"):
                (workspace / artifact).unlink(missing_ok=True)
            os.chown(workspace, 0, coder.pw_gid, follow_symlinks=False)
            workspace.chmod(0o775)
        if result.returncode != 0:
            raise RuntimeError(f"Aider failed ({result.returncode}): {result.stderr[-4000:]}")
        return result.stdout[-12_000:]

    def command(self, task_file: Path, files: tuple[str, ...] = ()) -> list[str]:
        command = [
            self.settings.agent_command,
            "--model",
            self.settings.agent_model,
            "--message-file",
            str(task_file),
            "--yes",
            "--no-auto-commits",
            "--no-dirty-commits",
            "--no-stream",
            "--no-gitignore",
            "--chat-history-file",
            "/dev/null",
            "--input-history-file",
            "/dev/null",
            "--no-analytics",
            "--edit-format",
            "udiff",
            "--timeout",
            "180",
        ]
        for filename in files:
            if (task_file.parent.parent / filename).is_file():
                command.extend(["--file", filename])
        return command