from __future__ import annotations

import json
import subprocess
import sys
from pathlib import Path

from app.core.config import Settings
from app.services.yolo_preflight_service import YoloPreflightService


ROOT = Path(__file__).resolve().parents[2]


class AvailableAdapter:
    @staticmethod
    def dependencies_available() -> bool:
        return True

    def __init__(self, settings: Settings) -> None:
        self.settings = settings

    def load_model(self, model_path: Path) -> object:
        return {"model_path": str(model_path)}


class MissingDependencyAdapter:
    @staticmethod
    def dependencies_available() -> bool:
        return False


class FailingLoadAdapter(AvailableAdapter):
    def load_model(self, model_path: Path) -> object:
        raise RuntimeError(f"cannot load {model_path}")


def _manifest(tmp_path: Path, tile_count: int = 1) -> Path:
    tiles = []
    for index in range(tile_count):
        tile_path = tmp_path / f"tile_{index:04d}.tif"
        tile_path.write_bytes(b"tile")
        tiles.append(
            {
                "path": str(tile_path),
                "pixel_window": [0, 0, 100, 100],
                "bounds": [4.0, 51.0, 5.0, 52.0],
                "transform": [4.0, 0.01, 0.0, 52.0, 0.0, -0.01],
                "index": index,
            }
        )
    manifest_path = tmp_path / "manifest.json"
    manifest_path.write_text(json.dumps({"tiles": tiles, "count": tile_count}), encoding="utf-8")
    return manifest_path


def test_yolo_preflight_reports_disabled_without_loading_model(tmp_path: Path) -> None:
    result = YoloPreflightService.run(
        settings=Settings(yolo_enabled=False, yolo_model_path=str(tmp_path / "missing.pt")),
        tile_manifest_path=str(tmp_path / "missing-manifest.json"),
        yolo_adapter_class=AvailableAdapter,
    )

    assert result["status"] == "not_configured"
    assert result["checks"]["enabled"] is False
    assert result["checks"]["dependencies_available"] is None
    assert result["checks"]["model_file_exists"] is None
    assert result["checks"]["manifest_valid"] is None


def test_yolo_preflight_distinguishes_missing_dependencies_from_missing_model(tmp_path: Path) -> None:
    model_path = tmp_path / "model.pt"
    model_path.write_bytes(b"weights")

    result = YoloPreflightService.run(
        settings=Settings(yolo_enabled=True, yolo_model_path=str(model_path)),
        tile_manifest_path=str(_manifest(tmp_path)),
        yolo_adapter_class=MissingDependencyAdapter,
    )

    assert result["status"] == "dependency_unavailable"
    assert result["checks"]["dependencies_available"] is False
    assert result["checks"]["model_file_exists"] is None
    assert result["checks"]["manifest_valid"] is None


def test_yolo_preflight_validates_model_and_manifest_without_importing_yolo(tmp_path: Path) -> None:
    model_path = tmp_path / "model.pt"
    model_path.write_bytes(b"weights")
    manifest_path = _manifest(tmp_path, tile_count=2)

    result = YoloPreflightService.run(
        settings=Settings(yolo_enabled=True, yolo_model_path=str(model_path), yolo_max_tiles=4),
        tile_manifest_path=str(manifest_path),
        yolo_adapter_class=AvailableAdapter,
    )

    assert result["status"] == "ready"
    assert result["checks"]["dependencies_available"] is True
    assert result["checks"]["model_file_exists"] is True
    assert result["checks"]["manifest_valid"] is True
    assert result["tile_count"] == 2
    assert result["will_download_models"] is False
    assert result["will_run_inference"] is False


def test_yolo_preflight_can_explicitly_smoke_load_local_model(tmp_path: Path) -> None:
    model_path = tmp_path / "model.pt"
    model_path.write_bytes(b"weights")
    manifest_path = _manifest(tmp_path)

    result = YoloPreflightService.run(
        settings=Settings(yolo_enabled=True, yolo_model_path=str(model_path), yolo_max_tiles=4),
        tile_manifest_path=str(manifest_path),
        yolo_adapter_class=AvailableAdapter,
        check_model_load=True,
    )

    assert result["status"] == "ready"
    assert result["checks"]["model_load_requested"] is True
    assert result["checks"]["model_load_ok"] is True
    assert result["will_download_models"] is False
    assert result["will_run_inference"] is False


def test_yolo_preflight_reports_explicit_model_load_failure(tmp_path: Path) -> None:
    model_path = tmp_path / "model.pt"
    model_path.write_bytes(b"weights")

    result = YoloPreflightService.run(
        settings=Settings(yolo_enabled=True, yolo_model_path=str(model_path), yolo_max_tiles=4),
        tile_manifest_path=str(_manifest(tmp_path)),
        yolo_adapter_class=FailingLoadAdapter,
        check_model_load=True,
    )

    assert result["status"] == "model_load_failed"
    assert result["error_code"] == "DETECTION_MODEL_LOAD_FAILED"
    assert result["checks"]["model_load_ok"] is False


def test_yolo_preflight_script_outputs_json(tmp_path: Path) -> None:
    model_path = tmp_path / "model.pt"
    model_path.write_bytes(b"weights")
    manifest_path = _manifest(tmp_path)

    result = subprocess.run(
        [
            sys.executable,
            str(ROOT / "scripts" / "yolo_preflight.py"),
            "--model-path",
            str(model_path),
            "--tile-manifest-path",
            str(manifest_path),
            "--assume-dependencies",
            "--json",
        ],
        cwd=ROOT,
        check=True,
        capture_output=True,
        text=True,
    )
    payload = json.loads(result.stdout)

    assert payload["status"] == "ready"
    assert payload["model_path"] == str(model_path)
    assert payload["tile_manifest_path"] == str(manifest_path)


def test_yolo_preflight_script_rejects_assumed_dependencies_for_model_load(tmp_path: Path) -> None:
    result = subprocess.run(
        [
            sys.executable,
            str(ROOT / "scripts" / "yolo_preflight.py"),
            "--model-path",
            str(tmp_path / "model.pt"),
            "--assume-dependencies",
            "--check-model-load",
            "--json",
        ],
        cwd=ROOT,
        check=False,
        capture_output=True,
        text=True,
    )

    assert result.returncode != 0
    assert "--check-model-load cannot be combined with --assume-dependencies" in result.stderr