"""Environment-based configuration for the service."""

from __future__ import annotations

import os
from dataclasses import dataclass, field
from pathlib import Path


def load_private_key() -> str:
    """Load private key from env var (raw PEM) or file path."""
    if raw := os.environ.get("GITHUB_PRIVATE_KEY"):
        return raw
    key_path = os.environ.get("GITHUB_PRIVATE_KEY_PATH", "")
    if key_path:
        return Path(key_path).read_text()
    msg = "Set GITHUB_PRIVATE_KEY or GITHUB_PRIVATE_KEY_PATH"
    raise ValueError(msg)


def default_plugin_dir() -> Path:
    """Default plugin dir is dist/ (assembled plugin) at the repo root."""
    env = os.environ.get("PLUGIN_DIR")
    if env:
        return Path(env)
    return Path(__file__).resolve().parents[3] / "dist"


@dataclass(frozen=True)
class Config:
    """Immutable configuration loaded from environment variables."""

    # GitHub App credentials
    app_id: int = field(
        default_factory=lambda: int(os.environ["GITHUB_APP_ID"]),
    )
    private_key: str = field(default_factory=load_private_key)
    webhook_secret: str = field(
        default_factory=lambda: os.environ["GITHUB_WEBHOOK_SECRET"],
    )

    # Claude CLI
    claude_cli: str = field(
        default_factory=lambda: os.environ.get("CLAUDE_CLI", "claude"),
    )
    claude_model: str = field(
        default_factory=lambda: os.environ.get(
            "CLAUDE_MODEL",
            "us.anthropic.claude-sonnet-4-5-20250929-v1:0",
        ),
    )
    plugin_dir: Path = field(default_factory=default_plugin_dir)

    # Codex CLI
    codex_cli: str = field(
        default_factory=lambda: os.environ.get("CODEX_CLI", "codex"),
    )
    codex_model: str = field(
        default_factory=lambda: os.environ.get(
            "CODEX_MODEL",
            "gpt-5.4",
        ),
    )

    # Backend selection
    lead_backend: str = field(
        default_factory=lambda: os.environ.get("LEAD_BACKEND", "claude"),
    )

    # Server
    host: str = field(
        default_factory=lambda: os.environ.get("HOST", "0.0.0.0"),
    )
    port: int = field(
        default_factory=lambda: int(os.environ.get("PORT", "8000")),
    )

    # Repo workspace
    workspace_dir: Path = field(
        default_factory=lambda: Path(
            os.environ.get(
                "WORKSPACE_DIR",
                "/tmp/codeflash-workspaces",
            ),
        ),
    )

    def cli_for_backend(self, name: str) -> str:
        """Return the CLI binary path for a backend name."""
        return {"claude": self.claude_cli, "codex": self.codex_cli}[name]

    def model_for_backend(self, name: str) -> str:
        """Return the model name for a backend name."""
        return {"claude": self.claude_model, "codex": self.codex_model}[name]