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MPV/mpv_lua_api.py

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+"""MPV Lua API - Clean interface for Lua scripts to call Python functions.
+
+This module provides a streamlined way for mpv Lua scripts to execute Python
+functions and commands without relying on the broken observe_property IPC pattern.
+
+Instead, Lua calls Python CLI directly via subprocess, and Python returns JSON
+responses that Lua can parse.
+"""
+
+import json
+import logging
+import sys
+from pathlib import Path
+from typing import Any, Dict, Optional
+
+# Add parent directory to path so we can import CLI, pipeline, cmdlet_catalog from root
+_SCRIPT_DIR = Path(__file__).parent
+_ROOT_DIR = _SCRIPT_DIR.parent
+if str(_ROOT_DIR) not in sys.path:
+    sys.path.insert(0, str(_ROOT_DIR))
+
+
+def setup_logging(log_file: Optional[Path] = None) -> logging.Logger:
+    """Setup logging for MPV API calls."""
+    logger = logging.getLogger("mpv-lua-api")
+    logger.setLevel(logging.DEBUG)
+    
+    if not logger.handlers:
+        if log_file:
+            handler = logging.FileHandler(str(log_file), encoding="utf-8")
+        else:
+            handler = logging.StreamHandler(sys.stderr)
+        
+        formatter = logging.Formatter(
+            "[%(asctime)s][%(levelname)s] %(message)s",
+            datefmt="%Y-%m-%d %H:%M:%S"
+        )
+        handler.setFormatter(formatter)
+        logger.addHandler(handler)
+    
+    return logger
+
+
+def log_to_helper(msg: str, log_file: Optional[Path] = None) -> None:
+    """Log a message that will appear in the helper log."""
+    if log_file:
+        with open(log_file, "a", encoding="utf-8") as f:
+            f.write(f"[lua] {msg}\n")
+
+
+def execute_pipeline(
+    pipeline_cmd: str,
+    log_file: Optional[Path] = None,
+    dry_run: bool = False,
+) -> Dict[str, Any]:
+    """Execute a pipeline command and return result as JSON.
+    
+    Args:
+        pipeline_cmd: Pipeline command string (e.g. "trim-file -path ... | add-file -store ...")
+        log_file: Optional path to helper log file for logging
+        dry_run: If True, log but don't execute
+    
+    Returns:
+        JSON object with keys: success, stdout, stderr, error, returncode
+    """
+    try:
+        if log_file:
+            log_to_helper(f"[api] execute_pipeline cmd={pipeline_cmd}", log_file)
+        
+        if dry_run:
+            return {
+                "success": True,
+                "stdout": "",
+                "stderr": "DRY RUN - command not executed",
+                "error": None,
+                "returncode": 0,
+                "cmd": pipeline_cmd,
+            }
+        
+        # Call the CLI directly as subprocess
+        import subprocess
+        import shlex
+        
+        # Parse the pipeline command into separate arguments
+        cmd_args = shlex.split(pipeline_cmd)
+        
+        result = subprocess.run(
+            [sys.executable, "-m", "CLI"] + cmd_args,
+            capture_output=True,
+            text=True,
+            cwd=str(_ROOT_DIR),
+            env={**dict(__import__('os').environ), "MEDEIA_MPV_CALLER": "lua"},
+        )
+        
+        if log_file:
+            log_to_helper(
+                f"[api] result returncode={result.returncode} len_stdout={len(result.stdout or '')} len_stderr={len(result.stderr or '')}",
+                log_file
+            )
+            if result.stderr:
+                log_to_helper(f"[api] stderr: {result.stderr[:500]}", log_file)
+        
+        return {
+            "success": result.returncode == 0,
+            "stdout": result.stdout or "",
+            "stderr": result.stderr or "",
+            "error": None if result.returncode == 0 else result.stderr,
+            "returncode": result.returncode,
+            "cmd": pipeline_cmd,
+        }
+    
+    except Exception as exc:
+        msg = f"{type(exc).__name__}: {exc}"
+        if log_file:
+            log_to_helper(f"[api] exception {msg}", log_file)
+        
+        return {
+            "success": False,
+            "stdout": "",
+            "stderr": str(exc),
+            "error": msg,
+            "returncode": 1,
+            "cmd": pipeline_cmd,
+        }
+
+
+def handle_api_request(request_json: str, log_file: Optional[Path] = None) -> str:
+    """Handle an API request from Lua and return JSON response.
+    
+    Request format:
+    {
+        "cmd": "execute_pipeline",
+        "pipeline": "trim-file -path ... | add-file -store ...",
+        ...
+    }
+    
+    Response format: JSON with result of the operation.
+    """
+    try:
+        request = json.loads(request_json)
+        cmd = request.get("cmd")
+        
+        if cmd == "execute_pipeline":
+            pipeline_cmd = request.get("pipeline", "")
+            result = execute_pipeline(pipeline_cmd, log_file)
+            return json.dumps(result)
+        
+        else:
+            return json.dumps({
+                "success": False,
+                "error": f"Unknown command: {cmd}",
+            })
+    
+    except Exception as exc:
+        return json.dumps({
+            "success": False,
+            "error": f"{type(exc).__name__}: {exc}",
+        })
+
+
+if __name__ == "__main__":
+    # When called from Lua via subprocess:
+    # python mpv_lua_api.py <json-request>
+    
+    if len(sys.argv) < 2:
+        print(json.dumps({"success": False, "error": "No request provided"}))
+        sys.exit(1)
+    
+    request_json = sys.argv[1]
+    log_file = Path(sys.argv[2]) if len(sys.argv) > 2 else None
+    
+    response = handle_api_request(request_json, log_file)
+    print(response)