"""Phase 4.1 benchmark — is "Regen N changed" actually ≤5s on a real clip?

Drives the full pipeline via HTTP: ingest URL → prep → transcribe → full
generate → edit one segment → regen-only → time it. Prints both wall-clocks.

Success criterion: incremental regen ≤ 5.0s (roadmap Phase 4.1 exit target).

Usage:
    uv run python scripts/bench_incremental.py [URL]

Default URL is the Fireship clip the user picked. Server must be live at
127.0.0.1:3900 with the models loaded (first cold run can take minutes).
"""
from __future__ import annotations

import json
import os
import sys
import time
import urllib.request
from urllib.error import HTTPError, URLError

API = "http://127.0.0.1:3900"
DEFAULT_URL = "https://www.youtube.com/watch?v=ZzI9JE0i6Lc"
TARGET_S = 5.0
# Cap baseline segments to keep full-dub wall-clock tractable. The incremental
# target is single-segment regen speed; 30 segs is plenty to populate caches
# for that measurement. Override via env.
MAX_SEGS = int(os.environ.get("BENCH_MAX_SEGS", "30"))


def post(path: str, body: dict) -> dict:
    req = urllib.request.Request(
        f"{API}{path}",
        data=json.dumps(body).encode(),
        headers={"Content-Type": "application/json"},
        method="POST",
    )
    with urllib.request.urlopen(req, timeout=600) as r:
        return json.loads(r.read().decode())


def stream_sse(url: str, on_event):
    """Parse SSE frames. Handles both shapes the backend emits:

      1. `data: {"type": "X", ...}` (prep pipeline, dub_generate)
      2. `event: X\\ndata: {...}`  (dub_transcribe — named events)

    Normalises both into {"type": <name>, ...payload}. `on_event` returning
    truthy stops the loop.
    """
    req = urllib.request.Request(f"{API}{url}")
    pending_event = None
    last = None
    # 1 hour read window — full-dub on a 489-seg clip can run long on Apple Silicon.
    with urllib.request.urlopen(req, timeout=3600) as r:
        for raw in r:
            line = raw.decode().rstrip("\r\n")
            if line.startswith("event:"):
                pending_event = line[6:].strip()
                continue
            if not line.startswith("data:"):
                # Blank line between frames resets named-event state.
                if not line:
                    pending_event = None
                continue
            body = line[5:].strip()
            try:
                payload = json.loads(body)
            except json.JSONDecodeError:
                continue
            if pending_event and isinstance(payload, dict) and "type" not in payload:
                payload = {"type": pending_event, **payload}
            last = payload
            if on_event(payload):
                return payload
    return last


def wait_prep(task_id: str) -> dict:
    print(f"  · streaming /tasks/stream/{task_id} …")

    def cb(ev):
        t = ev.get("type") or ev.get("stage")
        if t in ("ready", "done"):
            return True
        if t == "error":
            raise RuntimeError(f"prep error: {ev}")
        if ev.get("type") == "progress":
            s = ev.get("stage") or ""
            p = ev.get("pct")
            if p is not None:
                print(f"    prep {s} {int(p)}%")
            else:
                print(f"    prep {s}")
        return False

    return stream_sse(f"/tasks/stream/{task_id}", cb)


def transcribe(job_id: str) -> list[dict]:
    print(f"  · streaming /dub/transcribe-stream/{job_id} …")
    final: list[dict] = []

    def cb(ev):
        t = ev.get("type")
        if t == "final":
            # The diarised post-pass replaces per-chunk segs; this is what we want.
            final.extend(ev.get("segments", []))
        if t == "done":
            return True
        if t == "error":
            raise RuntimeError(f"transcribe error: {ev}")
        return False

    stream_sse(f"/dub/transcribe-stream/{job_id}", cb)
    return final


DUB_SEG_FIELDS = {"start", "end", "text", "instruct", "profile_id", "speed", "gain", "target_lang"}


def to_dub_segment(s: dict) -> dict:
    """Project a raw transcribe-output segment onto DubSegment's schema."""
    out = {k: v for k, v in s.items() if k in DUB_SEG_FIELDS}
    out.setdefault("text", s.get("text", ""))
    out.setdefault("start", float(s.get("start", 0.0)))
    out.setdefault("end", float(s.get("end", 0.0)))
    return out


def generate(job_id: str, segments: list[dict], *, regen_only: list[str] | None = None) -> dict:
    """POST → {task_id}, then stream /tasks/stream/{task_id} for SSE progress."""
    seg_ids = [str(s.get("id") or f"seg_{i}") for i, s in enumerate(segments)]
    body = {
        "segments": [to_dub_segment(s) for s in segments],
        "segment_ids": seg_ids,
        "language": "English",
        "language_code": "en",
    }
    if regen_only is not None:
        body["regen_only"] = regen_only

    r = post(f"/dub/generate/{job_id}", body)
    task_id = r["task_id"]

    done_ev = None

    def cb(ev):
        nonlocal done_ev
        t = ev.get("type")
        if t == "progress":
            print(f"    gen {ev.get('current', 0)}/{ev.get('total', '?')}",
                  end="\r", flush=True)
        elif t == "done":
            done_ev = ev
            return True
        elif t == "error":
            raise RuntimeError(f"generate error: {ev}")
        return False

    stream_sse(f"/tasks/stream/{task_id}", cb)
    print()
    if not done_ev:
        raise RuntimeError("generate task ended without 'done' event")
    return done_ev


def main():
    url = sys.argv[1] if len(sys.argv) > 1 else DEFAULT_URL
    print(f"Benchmark target: {TARGET_S}s incremental regen")
    print(f"Fixture URL:      {url}")

    try:
        urllib.request.urlopen(f"{API}/system/info", timeout=3)
    except (HTTPError, URLError) as e:
        sys.exit(f"Server not reachable at {API}: {e}")

    # 1. Ingest URL
    print("\n[1/4] Ingest URL …")
    r = post("/dub/ingest-url", {"url": url})
    job_id, task_id = r["job_id"], r["task_id"]
    print(f"  job_id={job_id} task_id={task_id}")

    # 2. Wait for prep
    print("\n[2/4] Prep (download / extract / demucs / scene) …")
    t0 = time.perf_counter()
    wait_prep(task_id)
    print(f"  prep: {time.perf_counter() - t0:.1f}s")

    # 3. Transcribe
    print("\n[3/4] Transcribe …")
    t0 = time.perf_counter()
    segments = transcribe(job_id)
    print(f"  transcribe: {time.perf_counter() - t0:.1f}s · {len(segments)} segments")
    if not segments:
        sys.exit("No segments returned — can't benchmark.")
    if len(segments) > MAX_SEGS:
        print(f"  · capping to first {MAX_SEGS} segs for baseline (BENCH_MAX_SEGS to change)")
        segments = segments[:MAX_SEGS]

    # 4a. Full generate (baseline — produces on-disk seg_N.wav)
    print("\n[4a/4] FULL generate (baseline) …")
    t0 = time.perf_counter()
    done = generate(job_id, segments)
    t_full = time.perf_counter() - t0
    print(f"  full generate: {t_full:.2f}s · {done.get('segments_processed', '?')} segs")

    # 4b. Edit ONE segment, regen only it
    edited = list(segments)
    edit_id = str(edited[0].get("id") or "seg_0")
    edited[0] = {**edited[0], "text": edited[0].get("text", "") + " (edited)"}

    print(f"\n[4b/4] INCREMENTAL regen (seg id={edit_id}) …")
    t0 = time.perf_counter()
    done_inc = generate(job_id, edited, regen_only=[edit_id])
    t_inc = time.perf_counter() - t0
    print(f"  incremental regen: {t_inc:.2f}s · {done_inc.get('segments_processed', '?')} segs")

    # 5. Verdict
    print("\n── verdict ──")
    print(f"  full dub:     {t_full:>7.2f}s")
    print(f"  incremental:  {t_inc:>7.2f}s   target ≤ {TARGET_S:.1f}s")
    passed = t_inc <= TARGET_S
    print(f"  exit 4.1:     {'✅ PASS' if passed else '❌ MISS'}")
    print(f"  speedup vs full: {t_full / t_inc:.1f}×")
    sys.exit(0 if passed else 1)


if __name__ == "__main__":
    main()