import sys
import os
import json
import logging
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

# Add backend to path
sys.path.append(os.path.join(os.getcwd(), 'backend'))

from src.models.activity import Activity
from src.models.segment import Segment
from src.services.segment_matcher import SegmentMatcher
from src.services.parsers import extract_points_from_file
from src.utils.geo import haversine_distance, calculate_bounds, ramer_douglas_peucker
from src.utils.config import config

# Setup DB
engine = create_engine(config.DATABASE_URL)
Session = sessionmaker(bind=engine)
db = Session()

def auto_create_segments(garmin_activity_id, split_dist_meters=1000):
    print(f"\n--- Auto Creating Segments for {garmin_activity_id} (Split: {split_dist_meters}m) ---")
    
    activity = db.query(Activity).filter(Activity.garmin_activity_id == garmin_activity_id).first()
    if not activity:
        print(f"Activity {garmin_activity_id} not found in DB.")
        return

    # Extract points
    points = extract_points_from_file(activity.file_content, activity.file_type)
    if not points or len(points) < 2:
        print("No points found in activity.")
        return
        
    print(f"Total Points: {len(points)}")
    
    accum_dist = 0.0
    split_start_idx = 0
    split_count = 1
    
    segments_created = []

    for i in range(1, len(points)):
        p1 = points[i-1]
        p2 = points[i]
        
        # dist between p1 and p2
        d = haversine_distance(p1[1], p1[0], p2[1], p2[0])
        accum_dist += d
        
        if accum_dist >= split_dist_meters:
            # Create segment
            split_end_idx = i
            
            seg_points = points[split_start_idx : split_end_idx + 1]
            
            # Simplify
            simple_points = ramer_douglas_peucker(seg_points, epsilon=5.0)
            bounds = calculate_bounds(seg_points)
            
            # Calc actual distance & elevation
            seg_dist = 0.0
            seg_elev_gain = 0.0
            for k in range(len(seg_points)-1):
                sp1 = seg_points[k]
                sp2 = seg_points[k+1]
                seg_dist += haversine_distance(sp1[1], sp1[0], sp2[1], sp2[0])
                if len(sp1) > 2 and len(sp2) > 2 and sp1[2] is not None and sp2[2] is not None:
                    diff = sp2[2] - sp1[2]
                    if diff > 0:
                        seg_elev_gain += diff

            name = f"AutoSplit #{split_count} ({garmin_activity_id})"
            
            print(f"Creating Segment: {name} | Dist: {seg_dist:.1f}m | Elev: {seg_elev_gain:.1f}m | Indices: {split_start_idx}-{split_end_idx}")
            
            segment = Segment(
                name=name,
                description=f"Auto-generated {split_dist_meters}m split",
                distance=seg_dist,
                elevation_gain=seg_elev_gain,
                activity_type=activity.activity_type or 'cycling',
                points=json.dumps(simple_points),
                bounds=json.dumps(bounds)
            )
            db.add(segment)
            segments_created.append(segment)
            
            # Reset for next split
            accum_dist = 0.0
            split_start_idx = i
            split_count += 1
            
    db.commit()
    print(f"\nCreated {len(segments_created)} segments.")
    
    # Trigger Matching
    if segments_created:
        print("\nTriggering Segment Matcher...")
        matcher = SegmentMatcher(db)
        matcher.match_activity(activity, points)
        print("Matching complete.")

if __name__ == "__main__":
    auto_create_segments("21249259141", 1000)