#!/usr/bin/env python3
import hashlib
import json
import os
import pathlib
import sys
import tempfile

import bpy


def preview_state(scene):
    return {
        "use": bool(scene.use_preview_range),
        "start": int(scene.frame_preview_start),
        "end": int(scene.frame_preview_end),
    }


def clear_preview_range():
    window = bpy.context.window
    screen = window.screen
    area = next(candidate for candidate in screen.areas if candidate.type == "DOPESHEET_EDITOR")
    region = next(candidate for candidate in area.regions if candidate.type == "WINDOW")
    with bpy.context.temp_override(window=window, screen=screen, area=area, region=region):
        poll = bool(bpy.ops.anim.previewrange_clear.poll())
        if not poll:
            raise RuntimeError("ANIM_OT_previewrange_clear poll failed in animation editor context")
        result = bpy.ops.anim.previewrange_clear()
    if "FINISHED" not in result:
        raise RuntimeError(f"ANIM_OT_previewrange_clear returned {result}")
    return poll, result


def main():
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 2:
        raise SystemExit("usage: blender -b --python check-action-previewrange-clear-desktop.py -- FIXTURE REPORT")
    fixture, output = (pathlib.Path(value).resolve() for value in arguments)
    output.unlink(missing_ok=True)
    bpy.ops.wm.open_mainfile(filepath=str(fixture), load_ui=False)
    scene = bpy.context.scene
    before = preview_state(scene)
    if before not in ({"use": True, "start": 2, "end": 6}, {"use": False, "start": 0, "end": 0}):
        raise RuntimeError(f"unexpected anim.previewrange_clear source state: {before}")
    evidence_status = "PRESERVED" if before["use"] is False else None
    poll, result = clear_preview_range()
    after = preview_state(scene)
    expected_after = {"use": False, "start": 0, "end": 0}
    if after != expected_after:
        raise RuntimeError(f"anim.previewrange_clear did not clear the preview range: {after}")

    descriptor, temporary = tempfile.mkstemp(prefix="m16-anim-previewrange-clear-reopen-", suffix=".blend")
    os.close(descriptor)
    temporary_path = pathlib.Path(temporary)
    try:
        bpy.ops.wm.save_as_mainfile(filepath=str(temporary_path), check_existing=False, compress=True)
        bpy.ops.wm.open_mainfile(filepath=str(temporary_path), load_ui=False)
        reopened = preview_state(bpy.context.scene)
        if reopened != expected_after:
            raise RuntimeError(f"anim.previewrange_clear save/reopen drift: {after} != {reopened}")
        if before["use"]:
            bpy.ops.wm.save_as_mainfile(filepath=str(fixture), check_existing=False, compress=True)
        report = {
            "schemaVersion": 1,
            "task": "M16-GAP-00200",
            "operation": "ANIM_PREVIEWRANGE_CLEAR_DESKTOP",
            "fixture": str(fixture),
            "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(),
            "before": before,
            "after": reopened,
            "poll": poll,
            "operatorStatus": "FINISHED" if "FINISHED" in result else sorted(result)[0],
            "mainMutation": "PREVIEW_RANGE_CLEARED",
            "saveReopen": "EXACT",
            "blenderVersion": bpy.app.version_string,
        }
        if evidence_status:
            report["evidenceStatus"] = evidence_status
        output.parent.mkdir(parents=True, exist_ok=True)
        output.write_text(json.dumps(report, indent=2, sort_keys=True) + "\n", encoding="utf-8")
        print("anim-previewrange-clear-desktop-ok poll=true status=FINISHED mainMutation=preview_range_cleared saveReopen=exact")
    finally:
        temporary_path.unlink(missing_ok=True)


if __name__ == "__main__":
    try:
        main()
    except Exception as error:
        print(f"anim-previewrange-clear-desktop-failed: {error}")
        raise SystemExit(1)