"""FastAPI app (spec M3). FROZEN after foundation — lanes never edit routes or shapes.

Serves the synthetic project fully so lane C can treat this API as finished:

    GET  /api/manifest            -> {videos:[{id,filename,url,duration_s,fps,width,height,
                                              offset_ms,drift_ppm}], t_global_max, has_poses}
    GET  /api/videos/{id}/poses   -> [{frame_idx,t_video_s,q:[w,x,y,z],t:[x,y,z],
                                      intrinsics:{fx,fy,cx,cy},registered}]
    GET  /api/pointcloud          -> points.ply (binary; Range-capable)
    GET  /api/anchors             -> [...]        POST /api/anchors
    GET  /api/events              -> [...]
    POST /api/events/detect       {t_global_s?, window_s?}  -> runs M7 detection
    POST /api/annotations         {video_id, t_video_s, bbox:[x0,y0,x1,y1]} -> {anchor_id?, point?}

Source videos in ``data/raw`` are mounted at ``/media`` via Starlette ``StaticFiles``,
which supports HTTP Range (required for ``<video>`` seeking; verify ``curl -H "Range:
bytes=0-100"`` -> 206). Stubbed lane entrypoints (events detection, M8 annotation
resolution) raise ``NotImplementedError``; we catch it here and degrade to a 200 with a
note so the frozen routes never 500 while a lane is still stubbed.
"""

from __future__ import annotations

import logging

from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel, Field

from festival4d import config, db

log = logging.getLogger("festival4d.api")

app = FastAPI(title="Festival 4D", version="0.1.0")

app.add_middleware(
    CORSMiddleware,
    allow_origins=config.FRONTEND_ORIGINS,
    allow_origin_regex=config.FRONTEND_ORIGIN_REGEX,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Bind the DB and ensure the media directory exists so the static mount is valid even
# before the synthetic fixture has been generated.
db.init_engine()
db.init_db()
config.RAW_DIR.mkdir(parents=True, exist_ok=True)

# HTTP Range-capable static serving of source videos (spec M3, pitfall #3).
app.mount("/media", StaticFiles(directory=config.RAW_DIR), name="media")

# Live capture (webcams / phones -> data/raw). OPT-IN: these routes accept file uploads, so they
# stay unmounted unless FESTIVAL4D_CAPTURE=1 — a public deployment must never expose them.
from festival4d import capture  # noqa: E402  (import after app/config are ready)

if capture.capture_enabled():
    app.include_router(capture.router)
    log.info("capture routes ENABLED (/capture, /api/capture/*) — FESTIVAL4D_CAPTURE is set")


# ---------------------------------------------------------------------------
# Request models
# ---------------------------------------------------------------------------
class AnchorIn(BaseModel):
    label: str
    x: float
    y: float
    z: float
    color: str | None = None


class DetectIn(BaseModel):
    t_global_s: float | None = None
    window_s: float | None = None


class AnnotationIn(BaseModel):
    video_id: int
    t_video_s: float
    bbox: list[float] = Field(min_length=4, max_length=4)  # [x0, y0, x1, y1] normalized
    event_id: int | None = None  # CR-2: link to the event this annotation locates (M8)


class EventPatch(BaseModel):
    event_type: str | None = None
    source: str | None = None
    description: str | None = None
    confidence: float | None = None


# ---------------------------------------------------------------------------
# Serialization helpers
# ---------------------------------------------------------------------------
def _video_dict(v) -> dict:
    return {
        "id": v.id,
        "filename": v.filename,
        "url": f"/media/{v.filename}",
        "duration_s": v.duration_s,
        "fps": v.fps,
        "width": v.width,
        "height": v.height,
        "offset_ms": v.offset_ms,
        "drift_ppm": v.drift_ppm,
    }


def _pose_dict(p) -> dict:
    return {
        "frame_idx": p.frame_idx,
        "t_video_s": p.t_video_s,
        "q": [p.qw, p.qx, p.qy, p.qz],
        "t": [p.tx, p.ty, p.tz],
        "intrinsics": {"fx": p.fx, "fy": p.fy, "cx": p.cx, "cy": p.cy},
        "registered": p.registered,
    }


def _anchor_dict(a) -> dict:
    return {"id": a.id, "label": a.label, "x": a.x, "y": a.y, "z": a.z, "color": a.color}


def _event_dict(e) -> dict:
    return {
        "id": e.id,
        "t_global_s": e.t_global_s,
        "duration_s": e.duration_s,
        "event_type": e.event_type,
        "confidence": e.confidence,
        "description": e.description,
        "source": e.source,
    }


# ---------------------------------------------------------------------------
# Routes
# ---------------------------------------------------------------------------
@app.get("/api/health")
def health() -> dict:
    return {"status": "ok"}


@app.get("/api/manifest")
def manifest() -> dict:
    videos = db.get_videos()
    t_global_max = 0.0
    for v in videos:
        offset_s = (v.offset_ms or 0.0) / 1000.0
        t_global_max = max(t_global_max, offset_s + v.duration_s)
    return {
        "videos": [_video_dict(v) for v in videos],
        "t_global_max": t_global_max,
        "has_capture": capture.capture_enabled(),
        "has_poses": db.has_poses(),
        "has_splat": config.SPLAT_PLY.exists(),
    }


@app.get("/api/videos/{video_id}/poses")
def video_poses(video_id: int) -> list[dict]:
    if db.get_video(video_id) is None:
        raise HTTPException(status_code=404, detail=f"no video with id={video_id}")
    return [_pose_dict(p) for p in db.get_poses(video_id)]


@app.get("/api/pointcloud")
def pointcloud() -> FileResponse:
    if not config.POINTS_PLY.exists():
        raise HTTPException(status_code=404, detail="no point cloud (run `synthetic` or `reconstruct`)")
    return FileResponse(
        config.POINTS_PLY,
        media_type="application/octet-stream",
        filename="points.ply",
    )


@app.get("/api/splat")
def splat() -> FileResponse:
    """Optional 3DGS splat of the scene (see docs/modelbeast-crossover.md).

    Trained externally from the same COLMAP reconstruction (e.g. MODELBEAST's
    brush_train) and dropped at ``data/work/splat.ply``. The viewer prefers it
    over the sparse point cloud when present.
    """
    if not config.SPLAT_PLY.exists():
        raise HTTPException(status_code=404, detail="no splat (train one — see docs/modelbeast-crossover.md)")
    return FileResponse(
        config.SPLAT_PLY,
        media_type="application/octet-stream",
        filename="splat.ply",
    )


@app.get("/api/anchors")
def get_anchors() -> list[dict]:
    return [_anchor_dict(a) for a in db.get_anchors()]


@app.post("/api/anchors")
def create_anchor(payload: AnchorIn) -> dict:
    anchor = db.add_anchor(payload.label, payload.x, payload.y, payload.z, payload.color)
    return _anchor_dict(anchor)


@app.get("/api/events")
def get_events() -> list[dict]:
    return [_event_dict(e) for e in db.get_events()]


@app.post("/api/events/detect")
def detect_events(payload: DetectIn) -> dict:
    from festival4d import events_ai

    try:
        result = events_ai.run_events(t_global_s=payload.t_global_s, window_s=payload.window_s)
    except NotImplementedError as exc:
        log.info("events detection not implemented yet: %s", exc)
        return {
            "result": None,
            "note": "moment detection not implemented yet (lane D / M7)",
            "events": [_event_dict(e) for e in db.get_events()],
        }
    return {"result": result, "events": [_event_dict(e) for e in db.get_events()]}


@app.patch("/api/events/{event_id}")
def patch_event(event_id: int, payload: EventPatch) -> dict:
    """Correct an event in place (M8). A user correction defaults ``source`` to ``'user'``."""
    if db.get_event(event_id) is None:
        raise HTTPException(status_code=404, detail=f"no event with id={event_id}")
    source = payload.source
    if source is None and (payload.event_type is not None or payload.description is not None):
        source = "user"  # any user-driven correction is attributed to the user
    event = db.update_event(
        event_id,
        event_type=payload.event_type,
        source=source,
        description=payload.description,
        confidence=payload.confidence,
    )
    return _event_dict(event)


@app.post("/api/annotations")
def create_annotation(payload: AnnotationIn) -> dict:
    from festival4d import resolve

    x0, y0, x1, y1 = payload.bbox
    if db.get_video(payload.video_id) is None:
        raise HTTPException(status_code=404, detail=f"no video with id={payload.video_id}")
    annotation = db.add_annotation(
        payload.video_id, payload.t_video_s, x0, y0, x1, y1, event_id=payload.event_id
    )

    # M8: cast a ray through the bbox center; triangulate against another view of the same
    # event, else fall back to the nearest point-cloud point / centroid depth.
    result = resolve.resolve_annotation(
        payload.video_id, payload.t_video_s, payload.bbox, event_id=payload.event_id
    )

    anchor = None
    superseded = False
    if result.point is not None:
        px, py, pz = result.point
        label = "annotation"
        if payload.event_id is not None:
            ev = db.get_event(payload.event_id)
            if ev is not None:
                label = ev.description or ev.event_type or label

        # One anchor per event: the first annotation creates it (a single-view fallback); a later
        # view that TRIANGULATES supersedes the anchor in place rather than dropping a sibling. A
        # later fallback links to the existing anchor without moving it (don't regress a good
        # triangulation). Annotations with no event stay independent (each makes its own anchor).
        existing_id = _existing_event_anchor_id(payload.event_id) if payload.event_id else None
        if existing_id is None:
            anchor = db.add_anchor(label, px, py, pz, None)
        elif result.method == "triangulated":
            anchor = db.update_anchor(existing_id, px, py, pz, label=label)
            superseded = True
        else:
            anchor = db.get_anchor(existing_id)
        if anchor is not None:
            db.set_annotation_anchor(annotation.id, anchor.id)

    return {
        "annotation_id": annotation.id,
        "anchor_id": anchor.id if anchor else None,
        "point": result.point,
        "method": result.method,
        "gap": result.gap,
        "superseded": superseded,
        "anchor": _anchor_dict(anchor) if anchor else None,
    }


def _existing_event_anchor_id(event_id: int) -> int | None:
    """The anchor resolved from a prior annotation of this event (most recent), or None."""
    for ann in reversed(db.get_annotations(event_id=event_id)):
        if ann.resolved_anchor_id is not None:
            return ann.resolved_anchor_id
    return None


@app.delete("/api/anchors/{anchor_id}")
def delete_anchor(anchor_id: int) -> dict:
    """Remove an anchor (M8 / Phase 4). Unlinks any annotations that resolved to it."""
    if not db.delete_anchor(anchor_id):
        raise HTTPException(status_code=404, detail=f"no anchor with id={anchor_id}")
    return {"deleted": anchor_id}