"""FastAPI proxy entrypoint — the guarding proxy of charter §4.

Skeleton: a health check plus the five role endpoints. Each role endpoint now
validates the posted canon log against the contract (charter §11) before doing
anything else — an invalid log is rejected with 422 and never reaches a prompt.
Prompt routing, model selection, and logging land later.
"""

from fastapi import Depends, FastAPI, HTTPException
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse
from pydantic import BaseModel

from .canon_log import validate_canon_log

app = FastAPI(title="coc-rpg proxy", version="0.0.1")


@app.exception_handler(RequestValidationError)
async def unify_validation_errors(request, exc: RequestValidationError) -> JSONResponse:
    """Reshape pydantic body-validation failures into the same envelope as a
    canon-log schema failure, so the client parses ONE 422 shape (charter §11):
    {"detail": {"canon_log_errors": [...]}}.
    """
    errors = [f"{'.'.join(str(loc) for loc in e['loc'])}: {e['msg']}" for e in exc.errors()]
    return JSONResponse(status_code=422, content={"detail": {"canon_log_errors": errors}})


class TurnRequest(BaseModel):
    canon_log: dict


def valid_turn(req: TurnRequest) -> TurnRequest:
    """Shared dependency: reject any request whose canon log breaks the contract."""
    errors = validate_canon_log(req.canon_log)
    if errors:
        raise HTTPException(status_code=422, detail={"canon_log_errors": errors})
    return req


@app.get("/health")
def health() -> dict:
    """Liveness probe for compose / fly.io."""
    return {"status": "ok"}


# ── Role endpoints (charter §4) ──────────────────────────────────────────────
# The client knows these paths and nothing about which model or prompt serves
# them. Bodies are validated against the canon log contract; the AI half is a
# stub until prompt routing lands.


@app.post("/dm/narrate")
def narrate(req: TurnRequest = Depends(valid_turn)) -> dict:
    return {"detail": "not implemented"}


@app.post("/dm/adjudicate")
def adjudicate(req: TurnRequest = Depends(valid_turn)) -> dict:
    return {"detail": "not implemented"}


@app.post("/dm/improvise")
def improvise(req: TurnRequest = Depends(valid_turn)) -> dict:
    return {"detail": "not implemented"}


@app.post("/npc/speak")
def npc_speak(req: TurnRequest = Depends(valid_turn)) -> dict:
    return {"detail": "not implemented"}


@app.post("/party/banter")
def banter(req: TurnRequest = Depends(valid_turn)) -> dict:
    return {"detail": "not implemented"}