from __future__ import annotations

import hashlib
import json
from pathlib import Path

import pytest

from k1link.compute import prepare_camera_compute_job, validate_camera_compute_job
from k1link.sessions import SessionIntegrityError, inspect_recorded_media_epoch
from k1link.web.camera_archive import CameraArchiveWriter


def _recorded_h264_fixture() -> tuple[bytes, bytes]:
    def box(box_type: bytes, payload: bytes = b"") -> bytes:
        return (8 + len(payload)).to_bytes(4, "big") + box_type + payload

    def full_box(box_type: bytes, payload: bytes = b"", *, flags: int = 0) -> bytes:
        return box(box_type, bytes([0]) + flags.to_bytes(3, "big") + payload)

    track_id = 1
    sample_duration = 500
    tkhd = full_box(
        b"tkhd",
        b"\x00" * 8 + track_id.to_bytes(4, "big") + b"\x00" * 4,
    )
    mdhd = full_box(
        b"mdhd",
        b"\x00" * 8 + (1_000).to_bytes(4, "big") + b"\x00" * 4,
    )
    hdlr = full_box(b"hdlr", b"\x00" * 4 + b"vide")
    trak = box(b"trak", tkhd + box(b"mdia", mdhd + hdlr))
    trex = full_box(
        b"trex",
        track_id.to_bytes(4, "big")
        + (1).to_bytes(4, "big")
        + sample_duration.to_bytes(4, "big")
        + b"\x00" * 8,
    )
    init = box(b"ftyp", b"isom") + box(
        b"moov",
        trak + box(b"mvex", trex) + box(b"avcC", b"\x01\x64\x00\x28"),
    )
    tfhd = full_box(b"tfhd", track_id.to_bytes(4, "big"), flags=0x020000)
    tfdt = full_box(b"tfdt", (0).to_bytes(4, "big"))
    trun = full_box(b"trun", (1).to_bytes(4, "big"))
    fragment = box(b"moof", box(b"traf", tfhd + tfdt + trun)) + box(b"mdat", b"frame")
    return init, fragment


def _camera_epoch(tmp_path: Path) -> tuple[Path, bytes]:
    session = tmp_path / "session-1"
    session.mkdir()
    init, fragment = _recorded_h264_fixture()
    writer = CameraArchiveWriter(session, "sensor.camera.left", 1)
    writer.append("init", init, host_epoch_ns=1_000_000_000, host_monotonic_ns=2_000_000_000)
    writer.append(
        "media",
        fragment,
        host_epoch_ns=1_500_000_000,
        host_monotonic_ns=2_500_000_000,
    )
    writer.close()
    return session, fragment


def test_camera_compute_job_is_content_addressed_and_idempotent(tmp_path: Path) -> None:
    session, fragment = _camera_epoch(tmp_path)
    source_epoch = session / "media" / "sensor.camera.left" / "epoch-1"
    source_identity = {
        path.relative_to(source_epoch).as_posix(): hashlib.sha256(path.read_bytes()).hexdigest()
        for path in source_epoch.rglob("*")
        if path.is_file()
    }

    job = prepare_camera_compute_job(
        session_root=session,
        source_id="sensor.camera.left",
        codec_epoch=1,
        origin_epoch_ns=1_000_000_000,
        origin_monotonic_ns=2_000_000_000,
        output_root=tmp_path / "jobs",
    )
    repeated = prepare_camera_compute_job(
        session_root=session,
        source_id="sensor.camera.left",
        codec_epoch=1,
        origin_epoch_ns=1_000_000_000,
        origin_monotonic_ns=2_000_000_000,
        output_root=tmp_path / "jobs",
    )

    assert repeated == job
    assert job.job_id == f"recorded-camera-{job.input_sha256[:24]}"
    assert job.segment_count == 1
    assert job.timeline_start_seconds == 0.0
    assert job.timeline_end_seconds == 0.5
    copied = (
        job.job_root / "input" / "camera" / "sensor.camera.left" / "epoch-1" / "segments" / "1.m4s"
    )
    assert copied.read_bytes() == fragment
    assert validate_camera_compute_job(job.job_root) == job
    assert source_identity == {
        path.relative_to(source_epoch).as_posix(): hashlib.sha256(path.read_bytes()).hexdigest()
        for path in source_epoch.rglob("*")
        if path.is_file()
    }


def test_camera_compute_job_rejects_changed_published_payload(tmp_path: Path) -> None:
    session, _ = _camera_epoch(tmp_path)
    job = prepare_camera_compute_job(
        session_root=session,
        source_id="sensor.camera.left",
        codec_epoch=1,
        origin_epoch_ns=1_000_000_000,
        origin_monotonic_ns=2_000_000_000,
        output_root=tmp_path / "jobs",
    )
    segment = next(job.job_root.glob("input/camera/*/epoch-1/segments/1.m4s"))
    segment.write_bytes(b"changed")

    with pytest.raises(SessionIntegrityError, match="payload identity changed"):
        validate_camera_compute_job(job.job_root)


def test_epoch_inspection_checks_summary_aggregate_digests(tmp_path: Path) -> None:
    session, _ = _camera_epoch(tmp_path)
    epoch = session / "media" / "sensor.camera.left" / "epoch-1"
    summary_path = epoch / "summary.json"
    summary = json.loads(summary_path.read_text(encoding="utf-8"))
    summary["index_sha256"] = "0" * 64
    summary_path.write_text(json.dumps(summary), encoding="utf-8")

    with pytest.raises(SessionIntegrityError, match="index digest changed"):
        inspect_recorded_media_epoch(
            epoch,
            expected_source_name="sensor.camera.left",
            origin_epoch_ns=1_000_000_000,
            origin_monotonic_ns=2_000_000_000,
        )