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

import bpy


def state_report(scene):
    return {
        "current": int(scene.frame_current),
        "start": int(scene.frame_start),
        "end": int(scene.frame_end),
    }


def write_report(fixture, output, state, *, evidence_status=None):
    report = {
        "schemaVersion": 1,
        "task": "M16-GAP-00177",
        "operation": "ANIM_END_FRAME_SET_DESKTOP",
        "fixture": str(fixture),
        "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(),
        "frame": state,
        "poll": True,
        "operatorStatus": "FINISHED",
        "mainMutation": "FRAME_END_SET",
        "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")


def foreground_end_frame_set(fixture, output):
    state = {"started": False}

    def finish_failure(message):
        print(f"anim-end-frame-set-desktop-failed: {message}")
        bpy.ops.wm.quit_blender()
        return None

    def execute():
        window = bpy.context.window
        if window is None:
            return 0.25
        scene = bpy.context.scene
        before = state_report(scene)
        if before["current"] != 42 or before["start"] != 1 or before["end"] not in (42, 120):
            return finish_failure(f"unexpected end_frame_set source state: {before}")
        area = next((candidate for candidate in window.screen.areas if candidate.type == "TIMELINE"), None)
        if area is None:
            area = next((candidate for candidate in window.screen.areas if candidate.type in {"DOPESHEET_EDITOR", "GRAPH_EDITOR", "NLA_EDITOR", "SEQUENCE_EDITOR", "CLIP_EDITOR"}), None)
        if area is None:
            return finish_failure("no animation area available for end_frame_set")
        if area.type == "TIMELINE":
            area.type = "DOPESHEET_EDITOR"
        region = next(candidate for candidate in area.regions if candidate.type == "WINDOW")
        try:
            with bpy.context.temp_override(window=window, screen=window.screen, area=area, region=region):
                poll = bool(bpy.ops.anim.end_frame_set.poll())
                result = bpy.ops.anim.end_frame_set()
        except Exception as error:
            return finish_failure(error)
        if not poll or result != {"FINISHED"}:
            return finish_failure(f"unexpected ANIM_OT_end_frame_set result: poll={poll} result={result}")
        after_operator = state_report(scene)
        if after_operator != {"current": 42, "start": 1, "end": 42}:
            return finish_failure(f"end_frame_set produced unexpected state: {after_operator}")
        descriptor, temporary = tempfile.mkstemp(prefix="m16-anim-end-frame-set-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 = state_report(bpy.context.scene)
            if reopened != after_operator:
                return finish_failure("anim.end_frame_set save/reopen drift")
            shutil.copyfile(temporary_path, fixture)
            write_report(fixture, output, reopened)
            print("anim-end-frame-set-desktop-ok poll=true status=FINISHED mainMutation=frame_end_set saveReopen=exact")
            bpy.ops.wm.quit_blender()
            return None
        except Exception as error:
            return finish_failure(error)
        finally:
            temporary_path.unlink(missing_ok=True)

    def start():
        if state["started"]:
            return 0.25
        state["started"] = True
        bpy.app.timers.register(execute, first_interval=1.0)
        return None

    bpy.app.timers.register(start, first_interval=1.5)


def main():
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 2:
        raise SystemExit("usage: blender -b --python check-action-end-frame-set-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)
    if bpy.app.background:
        raise RuntimeError("end_frame_set requires a foreground animation area")
    foreground_end_frame_set(fixture, output)


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