import asyncio
import contextlib
from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import FastAPI, HTTPException
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles
from sqlalchemy import text

import app.models  # noqa: F401 — registers models on Base.metadata before create_all
from app.db import Base, async_session_maker, engine
from app.routes.auth import router as auth_router
from app.routes.codex import router as codex_router
from app.routes.conditions import router as conditions_router
from app.routes.device import router as device_router
from app.routes.inventory import router as inventory_router
from app.routes.messages import router as messages_router
from app.routes.profile import router as profile_router
from app.routes.seances import router as seances_router
from app.routes.seo import router as seo_router
from app.routes.shop import router as shop_router
from app.session_cleanup import delete_expired_sessions
from app.ws import AUDIO_DIR
from app.ws import router as ws_router

FRONTEND_DIST = Path(__file__).resolve().parent.parent.parent / "frontend" / "dist"

SESSION_CLEANUP_INTERVAL_SECONDS = 30 * 60


async def _session_cleanup_loop() -> None:
    """Periodically sweeps expired auth_sessions rows so the table doesn't
    grow forever — get_current_user already rejects expired sessions on
    read, this just deletes the rows themselves."""
    try:
        while True:
            await asyncio.sleep(SESSION_CLEANUP_INTERVAL_SECONDS)
            try:
                async with async_session_maker() as db:
                    await delete_expired_sessions(db)
            except Exception:
                # A transient DB hiccup shouldn't kill the sweep loop —
                # just try again next interval.
                pass
    except asyncio.CancelledError:
        pass


@asynccontextmanager
async def lifespan(app: FastAPI):
    AUDIO_DIR.mkdir(parents=True, exist_ok=True)
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
        # No Alembic in this repo — `create_all` never alters existing
        # tables, so columns added to live models need a manual, idempotent
        # migration here. Safe to run on every startup.
        await conn.execute(text(
            "ALTER TABLE entities ADD COLUMN IF NOT EXISTS traits JSONB NOT NULL DEFAULT '{}'::jsonb"
        ))
        # Workstream C (character-depth-ghost-log spec) — missing from C's
        # own commit, added by the integrator after Workstream B's report
        # flagged that User.essence had a live model column and application
        # code (auth/me, inventory purchases, summon trickle) but no
        # migration, which would have broken on the real production DB.
        await conn.execute(text(
            "ALTER TABLE users ADD COLUMN IF NOT EXISTS essence INTEGER NOT NULL DEFAULT 0"
        ))
        # Workstream B (character-depth-ghost-log spec).
        await conn.execute(text(
            "ALTER TABLE users ADD COLUMN IF NOT EXISTS favor DOUBLE PRECISION NOT NULL DEFAULT 0.0"
        ))
        await conn.execute(text(
            "ALTER TABLE entities ADD COLUMN IF NOT EXISTS at_peace BOOLEAN NOT NULL DEFAULT false"
        ))
        # Any entity that predates the traits column above was left with
        # `{}` — the ALTER defaults it and nothing backfills. Every judgment
        # read then falls back to 0.5, which makes `trust` always correct and
        # `cross_over` unreachable for that spirit: the minigame is silently
        # solved for it. roll_traits() only ever runs at mint time, so such a
        # row can never repair itself.
        #
        # Seeded from the entity's own signature so the values are stable and
        # reproducible rather than random, matching how a freshly-minted
        # spirit derives them. Guarded to empty-traits rows only, so it can
        # never touch a spirit that already has a real hidden nature. This
        # install currently has zero such rows; the backfill exists so the
        # gap cannot bite a longer-lived deployment.
        await conn.execute(text(
            """
            UPDATE entities SET traits = jsonb_build_object(
                'alignment',    round((('x' || substr(md5(signature || 'alignment'),    1, 8))::bit(32)::bigint % 1000) / 1000.0, 3),
                'power',        round((('x' || substr(md5(signature || 'power'),        1, 8))::bit(32)::bigint % 1000) / 1000.0, 3),
                'volatility',   round((('x' || substr(md5(signature || 'volatility'),   1, 8))::bit(32)::bigint % 1000) / 1000.0, 3),
                'deceptiveness',round((('x' || substr(md5(signature || 'deceptiveness'),1, 8))::bit(32)::bigint % 1000) / 1000.0, 3)
            )
            WHERE traits = '{}'::jsonb OR traits IS NULL
            """
        ))

        # Hunter profile columns. All nullable (or defaulted) so existing
        # rows, guests included, stay valid without a backfill.
        for column, ddl in (
            ("display_name", "VARCHAR(48)"),
            ("bio", "VARCHAR(280)"),
            ("gender", "VARCHAR(16)"),
            ("avatar_form", "VARCHAR(16)"),
            ("avatar_hue", "INTEGER"),
        ):
            await conn.execute(
                text(f"ALTER TABLE users ADD COLUMN IF NOT EXISTS {column} {ddl}")
            )
        await conn.execute(text(
            "ALTER TABLE users ADD COLUMN IF NOT EXISTS "
            "profile_public BOOLEAN NOT NULL DEFAULT true"
        ))

        # Defense-in-depth: purchase_unlock() already enforces one row per
        # (user, unlock_key) via a row-locked check-then-insert, so this
        # constraint should never actually find a conflict on a live DB.
        # `ADD CONSTRAINT` has no IF NOT EXISTS form, so the guard is a
        # catalog check instead — safe to run on every startup.
        await conn.execute(text(
            "DO $$ BEGIN "
            "IF NOT EXISTS ("
            "  SELECT 1 FROM pg_constraint WHERE conname = 'uq_unlocks_user_key'"
            ") THEN "
            "  ALTER TABLE unlocks ADD CONSTRAINT uq_unlocks_user_key UNIQUE (user_id, unlock_key); "
            "END IF; "
            "END $$;"
        ))

        # The durable reward ledger (app/models/award_claim.py). `create_all`
        # above already builds this table on a fresh database; these two
        # statements are for an install that predates it — the CREATE is a
        # no-op there, and the constraint is what actually enforces
        # once-per-(seeker, presence, milestone), so it is asserted explicitly
        # rather than left to whatever the table happened to be created with.
        await conn.execute(text(
            """
            CREATE TABLE IF NOT EXISTS award_claims (
                id UUID PRIMARY KEY,
                user_id UUID NOT NULL REFERENCES users(id),
                entity_id UUID NOT NULL REFERENCES entities(id),
                award_key VARCHAR(64) NOT NULL,
                claimed_at TIMESTAMPTZ NOT NULL DEFAULT now()
            )
            """
        ))
        await conn.execute(text(
            "CREATE INDEX IF NOT EXISTS ix_award_claims_user_id ON award_claims (user_id)"
        ))
        await conn.execute(text(
            "CREATE INDEX IF NOT EXISTS ix_award_claims_entity_id ON award_claims (entity_id)"
        ))
        # Same catalog-check shape as uq_unlocks_user_key above: `ADD
        # CONSTRAINT` has no IF NOT EXISTS form. Unlike that one this
        # constraint is not defense-in-depth — it IS the guard: _claim_award
        # relies on the IntegrityError it raises to resolve two concurrent
        # connections claiming the same award down to a single payout.
        await conn.execute(text(
            "DO $$ BEGIN "
            "IF NOT EXISTS ("
            "  SELECT 1 FROM pg_constraint WHERE conname = 'uq_award_claims_user_entity_key'"
            ") THEN "
            "  ALTER TABLE award_claims ADD CONSTRAINT uq_award_claims_user_entity_key "
            "    UNIQUE (user_id, entity_id, award_key); "
            "END IF; "
            "END $$;"
        ))
    cleanup_task = asyncio.create_task(_session_cleanup_loop())
    try:
        yield
    finally:
        cleanup_task.cancel()
        with contextlib.suppress(asyncio.CancelledError):
            await cleanup_task


app = FastAPI(title="Quantumancy", lifespan=lifespan)
app.include_router(auth_router)
app.include_router(codex_router)
app.include_router(conditions_router)
app.include_router(device_router)
app.include_router(inventory_router)
app.include_router(messages_router)
app.include_router(profile_router)
app.include_router(seances_router)
# Registered before the SPA catch-all below, or /robots.txt and
# /sitemap.xml would be served index.html instead.
app.include_router(seo_router)
app.include_router(shop_router)
app.include_router(ws_router)


@app.get("/healthz")
async def healthz():
    return {"status": "ok"}


app.mount(
    "/assets",
    StaticFiles(directory=FRONTEND_DIST / "assets", check_dir=False),
    name="frontend-assets",
)
app.mount(
    "/audio",
    StaticFiles(directory=AUDIO_DIR, check_dir=False),
    name="spirit-audio",
)


@app.get("/{full_path:path}")
async def serve_spa(full_path: str):
    index_file = FRONTEND_DIST / "index.html"
    if not index_file.exists():
        raise HTTPException(
            status_code=503,
            detail="Frontend not built. Run `npm run build` in frontend/ and restart.",
        )

    # Vite emits root-level static files (favicon.ico, favicon.svg,
    # apple-touch-icon.png, og-image.png, …) straight into dist/ rather than
    # dist/assets/ — the only mounted static dir. Without this, requests for
    # them fall through to the SPA fallback below and get index.html back
    # instead of the actual file (browsers silently ignore it; social-media
    # link-preview crawlers fetching og:image get an HTML page).
    if full_path:
        dist_root = FRONTEND_DIST.resolve()
        candidate = (dist_root / full_path).resolve()
        if candidate.is_file() and dist_root in candidate.parents:
            return FileResponse(candidate)

    return FileResponse(index_file)