"""A10 renderer: provider request bodies are built from the canonical log at
call time, never stored provider-shaped.

First adapter: the OpenAI-compatible chat format LiteLLM's normalized route
speaks — the executor role's path (A5). The Anthropic passthrough adapter
arrives with delegations (A13). Token budgeting and prompt-cache breakpoints
are render-time concerns and are never stored (A10); neither exists yet in
this skeleton.
"""

import json
from typing import Any

from nisse_dev.canonical import (
    AssistantText,
    Compaction,
    DelegationCompleted,
    DelegationStarted,
    GateOpened,
    PlanSubmitted,
    StoredEvent,
    ToolCall,
    ToolResult,
    UserMessage,
)


def effective_events(stored: list[StoredEvent]) -> list[StoredEvent]:
    """Apply compactions: events whose ids fall in a compaction's replaced
    range are dropped; the compaction event itself stays as their summary."""
    replaced: list[tuple[int, int]] = [
        (e.event.replaces[0], e.event.replaces[1])
        for e in stored
        if isinstance(e.event, Compaction)
    ]

    def is_replaced(event_id: int) -> bool:
        return any(first <= event_id <= last for first, last in replaced)

    return [
        e for e in stored if isinstance(e.event, Compaction) or not is_replaced(e.id)
    ]


class OpenAIChatRenderer:
    """Mappings for orchestrator-side events (gates, plans, delegations,
    compaction summaries) are provisional; they get tuned when the executor
    loop (step 5) and delegations (step 7) consume them for real."""

    def render(
        self,
        events: list[StoredEvent],
        tools: list[dict[str, Any]] | None,
        model: str,
        system: str | None = None,
    ) -> dict[str, Any]:
        messages: list[dict[str, Any]] = []
        if system is not None:
            messages.append({"role": "system", "content": system})
        kept = effective_events(events)
        answered = {e.event.call_id for e in kept if isinstance(e.event, ToolResult)}
        for stored in kept:
            messages.append(self._message_for(stored.event))
            # Providers reject a tool call with no result following it. One
            # can legitimately be missing: a crash between the call and its
            # result (A3), or a turn-ending gate tool. Render a placeholder so
            # the transcript stays replayable rather than poisoned.
            if isinstance(stored.event, ToolCall) and (
                stored.event.call_id not in answered
            ):
                messages.append(
                    {
                        "role": "tool",
                        "tool_call_id": stored.event.call_id,
                        "content": "[no result recorded]",
                    }
                )
        body: dict[str, Any] = {"model": model, "messages": messages}
        if tools:
            body["tools"] = tools
        return body

    def _message_for(self, event: object) -> dict[str, Any]:
        match event:
            case UserMessage(text=text):
                return {"role": "user", "content": text}
            case AssistantText(text=text):
                return {"role": "assistant", "content": text}
            case ToolCall(call_id=call_id, tool=tool, arguments=arguments):
                return {
                    "role": "assistant",
                    "content": None,
                    "tool_calls": [
                        {
                            "id": call_id,
                            "type": "function",
                            "function": {
                                "name": tool,
                                "arguments": json.dumps(arguments),
                            },
                        }
                    ],
                }
            case ToolResult(call_id=call_id, result=result):
                return {
                    "role": "tool",
                    "tool_call_id": call_id,
                    "content": result,
                }
            case PlanSubmitted(plan=plan):
                return {"role": "assistant", "content": plan}
            case GateOpened(gate=gate, reason=reason):
                return {"role": "user", "content": f"[gate {gate} opened: {reason}]"}
            case DelegationStarted(brief=brief, model=model):
                return {
                    "role": "assistant",
                    "content": f"[delegation started ({model}): {brief}]",
                }
            case DelegationCompleted(handback=handback):
                return {
                    "role": "assistant",
                    "content": f"[delegation handback]\n{handback}",
                }
            case Compaction(summary=summary):
                return {
                    "role": "user",
                    "content": f"[summary of earlier conversation]\n{summary}",
                }
            case _:
                raise ValueError(f"unrenderable event: {event!r}")