#!/usr/bin/env python3
"""Transition project between phases."""

import argparse
import json
import os
from datetime import datetime

VALID_PHASES = ["DESIGN_PHASE", "DESIGN_REVIEW", "IMPLEMENTATION_PHASE"]
VALID_TRANSITIONS = {
    "DESIGN_PHASE": ["DESIGN_REVIEW"],
    "DESIGN_REVIEW": ["DESIGN_PHASE", "IMPLEMENTATION_PHASE"],
    "IMPLEMENTATION_PHASE": ["DESIGN_PHASE"]
}


def load_manifest(manifest_path: str) -> dict:
    """Load manifest."""
    with open(manifest_path) as f:
        return json.load(f)


def save_manifest(manifest_path: str, manifest: dict):
    """Save manifest."""
    with open(manifest_path, "w") as f:
        json.dump(manifest, f, indent=2)


def main():
    parser = argparse.ArgumentParser(description="Transition project phase")
    parser.add_argument("--to", required=True, choices=VALID_PHASES, help="Target phase")
    parser.add_argument("--manifest", default="project_manifest.json", help="Manifest path")
    args = parser.parse_args()

    manifest_path = args.manifest
    if not os.path.isabs(manifest_path):
        manifest_path = os.path.join(os.getcwd(), manifest_path)

    if not os.path.exists(manifest_path):
        print(f"Error: Manifest not found at {manifest_path}")
        return 1

    manifest = load_manifest(manifest_path)
    current_phase = manifest["state"]["current_phase"]
    target_phase = args.to

    if target_phase not in VALID_TRANSITIONS.get(current_phase, []):
        print(f"Error: Cannot transition from {current_phase} to {target_phase}")
        print(f"Valid transitions: {VALID_TRANSITIONS.get(current_phase, [])}")
        return 1

    # Update phase
    manifest["state"]["current_phase"] = target_phase
    
    # Add to history
    manifest["state"]["revision_history"].append({
        "action": "PHASE_TRANSITION",
        "timestamp": datetime.now().isoformat(),
        "details": f"Transitioned from {current_phase} to {target_phase}"
    })

    # If transitioning to implementation, mark entities as approved
    if target_phase == "IMPLEMENTATION_PHASE":
        for entity_type in ["pages", "components", "api_endpoints", "database_tables"]:
            for entity in manifest["entities"].get(entity_type, []):
                if entity.get("status") == "DEFINED":
                    entity["status"] = "APPROVED"

    save_manifest(manifest_path, manifest)
    print(f"Transitioned to {target_phase}")
    return 0


if __name__ == "__main__":
    exit(main())