"""Simulate a merge: modify a file, regenerate its doc, mark downstream stale."""

import sys
import os
import time

sys.path.insert(0, os.path.dirname(__file__))

from db import GraphDB
from docgen import generate_file_doc

REPO_DIR = os.environ.get("REPO_DIR", os.path.join(os.path.dirname(__file__), "repos", "target"))


def simulate_merge(file_path: str, new_content: str = None):
    db = GraphDB()

    print(f"\n{'='*60}")
    print(f"Simulating merge: {file_path}")
    print(f"{'='*60}")

    # Get current doc (before)
    f = db.get_file(file_path)
    if not f:
        print(f"ERROR: File {file_path} not found in graph")
        db.close()
        return

    print(f"\n[BEFORE] Documentation for {file_path}:")
    print(f"  {f['documentation'][:300]}")

    # Read file content (or use provided)
    if new_content is None:
        full_path = os.path.join(REPO_DIR, file_path)
        if os.path.exists(full_path):
            with open(full_path) as fh:
                original = fh.read()
            new_content = original + """

// EnableTracing adds distributed request tracing with correlation IDs
// across the middleware chain. Each request gets a unique trace ID propagated
// through all handlers for end-to-end debugging in microservice architectures.
func (e *Echo) EnableTracing(correlationHeader string) {
    e.tracingEnabled = true
    e.correlationHeader = correlationHeader
}
"""
        else:
            print(f"ERROR: File not found on disk: {full_path}")
            db.close()
            return

    # Regenerate doc for changed file
    print(f"\n[MERGE] Regenerating documentation for {file_path}...")
    new_doc = generate_file_doc(file_path, new_content)

    commit_hash = f"sim-{int(time.time())}"
    db.update_file_doc(file_path, new_doc, commit_hash)

    print(f"\n[AFTER] Documentation for {file_path}:")
    print(f"  {new_doc[:300]}")

    # Mark downstream stale
    print(f"\n[CASCADE] Marking downstream as stale...")
    db.mark_relationships_stale(file_path)

    repo = db.get_repo()
    if repo:
        db.mark_repo_stale(repo["name"])
        print(f"  Repo '{repo['name']}' marked stale")

    stats = db.get_stats()
    print(f"  Stale relationships: {stats['stale_relationships']}")

    print(f"\n{'='*60}")
    print("Merge simulation complete.")
    print(f"  File doc:       REGENERATED (fresh)")
    print(f"  Relationships:  STALE (awaiting refresh)")
    print(f"  Repo doc:       STALE (awaiting refresh)")
    print(f"\nRun: python refresh_stale.py")
    print(f"Or ask Claude Code — stale docs show [STALE] indicator.")
    print(f"{'='*60}")

    db.close()


if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python simulate_merge.py <file_path>")
        print("Example: python simulate_merge.py echo.go")
        sys.exit(1)

    target = sys.argv[1]
    content = None
    if len(sys.argv) > 2:
        with open(sys.argv[2]) as f:
            content = f.read()

    simulate_merge(target, content)