"""
process.py — Nuke terminal-mode batch renderer.

This script runs INSIDE Nuke and must not import anything outside the
Python standard library or Nuke's own modules.

Usage (called by nuke_runner.py):
    Nuke.exe -t process.py <jobs.json>

jobs.json schema
----------------
{
    "template_script": "/abs/path/to/proxy_template.nk",
    "jobs": [
        {
            "basename":       "SHOW_EP_SEQ_SHOT_ELEM_TASK_v001",
            "input_sequence": "/path/SHOW_..._%05d.exr",
            "first_frame":    1001,
            "last_frame":     1100,
            "output_folder":  "/output/SHOW/SHOW_EP/basename",
            "output_movie":   "/output/.../basename.mov",
            "output_exr":     "/output/.../basename.%05d.exr"
        },
        ...
    ]
}

Expected template nodes
-----------------------
  Read_Input   — source EXR sequence
  Overlay      — text burn-in; knob 'bottomleft' is set to the shot basename
  Write_4k     — EXR sequence output  (file = output_exr)
  Write_h264   — MOV / H.264 output   (file = output_movie)

Both Write nodes are executed in a single nuke.execute() call so the
graph is only evaluated once per frame.

Progress lines printed to stdout (parsed by nuke_runner.py):
    [1/10] Rendering: <basename>
    [1/10] Done: <basename>
    [1/10] ERROR: <basename>: <message>
"""
from __future__ import annotations

import json
import os
import sys


def _log(msg: str) -> None:
    """Print *msg* and flush immediately so the parent process receives it."""
    print(msg)
    sys.stdout.flush()


def main() -> None:
    # ── Locate jobs file ──────────────────────────────────────────────
    # When launched as: Nuke.exe -t process.py jobs.json
    # sys.argv is typically: ['process.py', 'jobs.json']
    if len(sys.argv) < 2:
        _log("ERROR: Usage: Nuke.exe -t process.py <jobs.json>")
        sys.exit(1)

    jobs_path = sys.argv[1]
    if not os.path.isfile(jobs_path):
        _log(f"ERROR: Jobs file not found: {jobs_path}")
        sys.exit(1)

    try:
        with open(jobs_path, encoding="utf-8") as fh:
            payload = json.load(fh)
    except Exception as exc:
        _log(f"ERROR: Cannot parse jobs file: {exc}")
        sys.exit(1)

    template_script = payload.get("template_script", "")
    jobs = payload.get("jobs", [])
    total = len(jobs)

    if not jobs:
        _log("No jobs to process.")
        return

    # ── Import Nuke ───────────────────────────────────────────────────
    try:
        import nuke  # noqa: PLC0415
    except ImportError:
        _log("ERROR: 'nuke' module not available. This script must run inside Nuke.")
        sys.exit(1)

    # ── Open template ─────────────────────────────────────────────────
    if not os.path.isfile(template_script):
        _log(f"ERROR: Template script not found: {template_script}")
        sys.exit(1)

    _log(f"Loading template: {template_script}")
    nuke.scriptOpen(template_script)

    read_node    = nuke.toNode("Read_Input")
    overlay_node = nuke.toNode("Overlay")
    write_4k     = nuke.toNode("Write_4k")
    write_h264   = nuke.toNode("Write_h264")

    if read_node is None:
        _log("ERROR: Node 'Read_Input' not found in template.")
        sys.exit(1)
    if write_4k is None:
        _log("ERROR: Node 'Write_4k' not found in template.")
        sys.exit(1)
    if write_h264 is None:
        _log("ERROR: Node 'Write_h264' not found in template.")
        sys.exit(1)
    if overlay_node is None:
        _log("WARNING: Node 'Overlay' not found in template — bottomleft will not be set.")

    # ── Process jobs ──────────────────────────────────────────────────
    for idx, job in enumerate(jobs, start=1):
        basename = job.get("basename", f"job_{idx}")
        _log(f"[{idx}/{total}] Rendering: {basename}")

        try:
            first      = int(job["first_frame"])
            last       = int(job["last_frame"])
            input_seq  = job["input_sequence"]
            output_mov = job["output_movie"]
            output_exr = job["output_exr"]
            output_folder = job.get("output_folder", "")

            # Ensure output directory exists
            target_dir = output_folder or os.path.dirname(output_mov)
            if target_dir:
                os.makedirs(target_dir, exist_ok=True)

            # Configure Read node
            read_node["file"].setValue(input_seq)
            read_node["first"].setValue(first)
            read_node["last"].setValue(last)
            read_node["origfirst"].setValue(first)
            read_node["origlast"].setValue(last)

            # Set burn-in text on the Overlay node
            if overlay_node is not None:
                overlay_node["bottomleft"].setValue(basename)

            # Configure both Write nodes
            write_4k["file"].setValue(output_exr)
            write_h264["file"].setValue(output_mov)

            # Render both Write nodes (sequential calls; list form not supported in all versions)
            nuke.execute(write_4k, first, last, 1)
            nuke.execute(write_h264, first, last, 1)

            _log(f"[{idx}/{total}] Done: {basename}")

        except Exception as exc:  # noqa: BLE001
            _log(f"[{idx}/{total}] ERROR: {basename}: {exc}")

        # Free memory caches between jobs to avoid RAM build-up
        for fn in ("clearRAMCache", "memory2", "memory"):
            func = getattr(nuke, fn, None)
            if func is not None:
                try:
                    func("free")
                except Exception:
                    pass
                break

    _log("All jobs complete.")


if __name__ == "__main__":
    main()