from __future__ import annotations

from app.schemas import MultiStatusOut

# Rendered as Prometheus text exposition format (no client library needed).
# The route serves this at GET /api/metrics for the existing Prometheus scrape.


def _escape(value: str) -> str:
    return value.replace("\\", "\\\\").replace('"', '\\"')


def _metric(
    name: str, help_text: str, value: float | int, labels: dict[str, str] | None = None
) -> str:
    lines = [f"# HELP {name} {help_text}", f"# TYPE {name} gauge"]
    if labels:
        rendered = ",".join(f'{k}="{_escape(v)}"' for k, v in labels.items())
        lines.append(f"{name}{{{rendered}}} {value}")
    else:
        lines.append(f"{name} {value}")
    return "\n".join(lines)


def render_metrics(status: MultiStatusOut, mode: str, exchange: str) -> str:
    """Render the current portfolio state as Prometheus metrics."""
    parts = [
        _metric("crypto_running", "1 when the bot is running", int(status.running)),
        _metric("crypto_equity", "Total account equity", status.equity),
        _metric("crypto_starting_balance", "Starting balance", status.starting_balance),
        _metric("crypto_total_pnl", "Total profit and loss", status.total_pnl),
        _metric(
            "crypto_open_positions",
            "Number of open positions across strategies",
            sum(s.open_positions for s in status.strategies),
        ),
        _metric(
            "crypto_strategies",
            "Number of configured strategies",
            len(status.strategies),
        ),
    ]

    if status.price is not None:
        parts.append(_metric("crypto_price", "Latest mark price", status.price))

    # Common labels shared by the per-strategy families.
    lines = [
        "# HELP crypto_strategy_equity Equity per strategy",
        "# TYPE crypto_strategy_equity gauge",
    ]
    for s in status.strategies:
        labels = {"strategy": s.strategy_key, "symbol": s.symbol}
        rendered = ",".join(f'{k}="{_escape(v)}"' for k, v in labels.items())
        lines.append(f"crypto_strategy_equity{{{rendered}}} {s.equity}")
    parts.append("\n".join(lines))

    lines = [
        "# HELP crypto_strategy_pnl Total P&L per strategy",
        "# TYPE crypto_strategy_pnl gauge",
    ]
    for s in status.strategies:
        labels = {"strategy": s.strategy_key, "symbol": s.symbol}
        rendered = ",".join(f'{k}="{_escape(v)}"' for k, v in labels.items())
        lines.append(f"crypto_strategy_pnl{{{rendered}}} {s.total_pnl}")
    parts.append("\n".join(lines))

    lines = [
        "# HELP crypto_strategy_allocation Fraction of the balance per strategy",
        "# TYPE crypto_strategy_allocation gauge",
    ]
    for s in status.strategies:
        labels = {"strategy": s.strategy_key}
        rendered = ",".join(f'{k}="{_escape(v)}"' for k, v in labels.items())
        lines.append(f"crypto_strategy_allocation{{{rendered}}} {s.allocation}")
    parts.append("\n".join(lines))

    lines = [
        "# HELP crypto_strategy_halted 1 when a strategy is halted",
        "# TYPE crypto_strategy_halted gauge",
    ]
    for s in status.strategies:
        labels = {"strategy": s.strategy_key}
        rendered = ",".join(f'{k}="{_escape(v)}"' for k, v in labels.items())
        lines.append(f"crypto_strategy_halted{{{rendered}}} {int(s.halted)}")
    parts.append("\n".join(lines))

    info_labels = {"mode": mode, "exchange": exchange}
    rendered = ",".join(f'{k}="{_escape(v)}"' for k, v in info_labels.items())
    parts.append(
        "# HELP crypto_info Build information\n"
        "# TYPE crypto_info gauge\n"
        f"crypto_info{{{rendered}}} 1"
    )

    return "\n".join(parts) + "\n"