"""
Google Takeout pre-processor.
Detects Takeout folder structures, reads JSON sidecars, and enriches
the files table with corrected timestamps, normalized filenames, and
edit-version flags.
"""

import json
import os
import re
import sqlite3
from datetime import datetime, timezone
from pathlib import Path


# Google edit suffixes appended to filenames
EDIT_SUFFIXES = ("-edited", "-effects", "-smile", "-mix")


def _find_sidecar(media_path: str) -> str | None:
    """Return path to the JSON sidecar for a media file, or None."""
    p = Path(media_path)
    # Try filename.ext.json first, then filename.json
    candidates = [
        str(p) + ".json",
        str(p.with_suffix(".json")),
    ]
    for c in candidates:
        if os.path.isfile(c):
            return c
    return None


def _strip_collision_suffix(filename: str) -> str:
    """Strip Google's (1), (2) collision suffixes from a filename."""
    stem = Path(filename).stem
    ext = Path(filename).suffix
    cleaned = re.sub(r"\(\d+\)$", "", stem).rstrip()
    return cleaned + ext


def _is_edited(filename: str) -> bool:
    stem = Path(filename).stem.lower()
    return any(stem.endswith(s) for s in EDIT_SUFFIXES)


def is_takeout_folder(folder_path: str) -> bool:
    """
    Heuristic: walk folder looking for .json files whose names match
    adjacent media files. If we find at least 5 such pairs, call it Takeout.
    """
    count = 0
    dirs_checked = 0
    MAX_DIRS = 50   # sample at most 50 directories — fast on any library size

    for root, dirs, files in os.walk(folder_path):
        dirs[:] = [d for d in dirs if not d.startswith(".")]
        dirs_checked += 1
        if dirs_checked > MAX_DIRS:
            break

        file_set = set(files)
        for f in files:
            if not f.endswith(".json"):
                continue
            base = f[:-5]  # strip .json
            if base in file_set:
                count += 1
            if count >= 5:
                return True
    return False


def process_takeout(folder_path: str, db_path: str) -> int:
    """
    Walk folder_path, find all media files with JSON sidecars,
    and enrich their DB records. Returns count of files enriched.
    """
    con = sqlite3.connect(db_path)
    con.row_factory = sqlite3.Row
    cur = con.cursor()

    enriched = 0

    for root, dirs, files in os.walk(folder_path):
        dirs[:] = [d for d in dirs if not d.startswith(".")]
        for fname in files:
            if fname.endswith(".json"):
                continue
            media_path = os.path.join(root, fname)
            sidecar = _find_sidecar(media_path)
            if not sidecar:
                continue

            try:
                with open(sidecar, "r", encoding="utf-8") as f:
                    data = json.load(f)
            except (json.JSONDecodeError, OSError):
                continue

            # Extract fields from sidecar
            photo_taken_ts = None
            try:
                ts = int(data["photoTakenTime"]["timestamp"])
                dt = datetime.fromtimestamp(ts, tz=timezone.utc)
                photo_taken_ts = dt.strftime("%Y-%m-%dT%H:%M:%S")
            except (KeyError, ValueError, TypeError):
                pass

            title = data.get("title", "")
            takeout_json_str = json.dumps(data)

            # Normalized filename: use title if present, else strip suffix from fname
            if title:
                normalized = _strip_collision_suffix(title)
            else:
                normalized = _strip_collision_suffix(fname)

            edited = _is_edited(fname)

            # Update the DB record for this file
            updates = {
                "is_takeout": 1,
                "filename": normalized,
                "takeout_json": takeout_json_str,
            }
            if photo_taken_ts:
                updates["exif_datetime"] = photo_taken_ts

            set_clause = ", ".join(f"{k} = ?" for k in updates)
            values = list(updates.values()) + [media_path]

            cur.execute(
                f"UPDATE files SET {set_clause}, updated_at = CURRENT_TIMESTAMP "
                f"WHERE path = ?",
                values,
            )

            # Handle edited flag — add is_edited column if needed (migration-safe)
            if edited:
                try:
                    cur.execute(
                        "UPDATE files SET is_edited = 1 WHERE path = ?",
                        (media_path,),
                    )
                except sqlite3.OperationalError:
                    pass  # column doesn't exist yet, skip

            if cur.rowcount > 0:
                enriched += 1

    con.commit()
    con.close()
    return enriched