#!/usr/bin/env python3
"""Sew all frame CSVs in order; deduplicate overlap at boundaries (scroll down)."""
import csv
import os
import re
import sys

from row_eq import row_equal


def frame_number_from_name(name):
    m = re.match(r"^(\d+)\.csv$", name)
    return int(m.group(1)) if m else None


def list_frame_csvs(frames_dir):
    names = []
    for name in os.listdir(frames_dir):
        n = frame_number_from_name(name)
        if n is not None:
            names.append((n, name))
    return [name for _, name in sorted(names)]


def read_csv(path):
    with open(path, newline="", encoding="utf-8") as f:
        return list(csv.reader(f))


def write_csv(path, rows):
    with open(path, "w", newline="", encoding="utf-8") as f:
        csv.writer(f).writerows(rows)


def overlap_length(acc_rows, next_rows, num_cols=6):
    max_k = min(len(acc_rows), len(next_rows))
    for k in range(max_k, 0, -1):
        if k > len(acc_rows) or k > len(next_rows):
            continue
        match = True
        for i in range(k):
            if not row_equal(acc_rows[-k + i], next_rows[i], num_cols):
                match = False
                break
        if match:
            return k
    return 0


def dedupe_rows(rows, num_cols=6):
    seen = set()
    out = []
    for row in rows:
        key = tuple((row[i] if i < len(row) else "").strip() for i in range(num_cols))
        if key in seen:
            continue
        seen.add(key)
        out.append(row)
    return out


def sew(frames_dir, out_path, num_cols=6, dedupe=True):
    csv_names = list_frame_csvs(frames_dir)
    if not csv_names:
        return 0
    acc = read_csv(os.path.join(frames_dir, csv_names[0]))
    for name in csv_names[1:]:
        next_rows = read_csv(os.path.join(frames_dir, name))
        k = overlap_length(acc, next_rows, num_cols)
        acc.extend(next_rows[k:])
    if dedupe:
        acc = dedupe_rows(acc, num_cols)
    write_csv(out_path, acc)
    return len(acc)


def main():
    frames_dir = sys.argv[1] if len(sys.argv) > 1 else "frames"
    out_path = sys.argv[2] if len(sys.argv) > 2 else "result.csv"
    n = sew(frames_dir, out_path)
    print(f"Wrote {n} rows to {out_path}")


if __name__ == "__main__":
    main()