card-grader/store.py

"""SQLite: settings and a log of past grade estimates.

One database, two tables. There is no inventory or pricing here — this app
does exactly one thing (estimate a PSA grade from photos) and remembers what
it told you, so you can look back at a card without re-running the estimate.
"""

import base64
import json
import os
import sqlite3
import time

BASE_DIR = os.path.dirname(os.path.abspath(__file__))
# Overridable so a container can point this at a mounted volume (e.g.
# /data/grades.db) instead of the app's own directory, which is what makes
# the data survive a container recreate/image update.
DB_PATH = os.environ.get("CARD_GRADER_DB_PATH") or os.path.join(BASE_DIR, "grades.db")

SCHEMA = """
CREATE TABLE IF NOT EXISTS settings (
    key   TEXT PRIMARY KEY,
    value TEXT
);

CREATE TABLE IF NOT EXISTS grades (
    id                   INTEGER PRIMARY KEY AUTOINCREMENT,
    created_at           TEXT NOT NULL,
    label                TEXT,              -- your own name for the card, optional
    card_type            TEXT,              -- pokemon | sports | other_tcg | other
    card_note            TEXT,              -- what the model read off the card
    image_count          INTEGER,
    thumbnail            TEXT,              -- small JPEG, base64 — first photo only
    model                TEXT,
    estimated_grade      INTEGER,
    grade_low            INTEGER,
    grade_high           INTEGER,
    confidence           TEXT,
    categories_json      TEXT,
    edge_measurements_json     TEXT,
    centering_measurement_json TEXT,
    aspect_measurement_json    TEXT,
    limitations_json     TEXT,
    note                 TEXT,
    estimated_cost       REAL,
    usage_json           TEXT,
    source_images_json   TEXT   -- the original photo(s), for Regrade; NOT sent
                                 -- to the browser in list/detail responses —
                                 -- see get_grade_images vs get_grade/list_grades
);

CREATE INDEX IF NOT EXISTS idx_grades_created ON grades(created_at DESC);
"""

DEFAULT_SETTINGS = {
    "anthropic_api_key": "",
    "vision_model": "claude-sonnet-5",
    "vision_effort": "low",
}

# How long a grade keeps the original photo(s) that produced it. They exist
# so Regrade can re-run without asking for the photo again, which is worth
# most right after a grading-logic change — a value that decays fast. What
# doesn't decay is the grade record itself, so only the images are dropped
# here; the history row, its thumbnail and every measurement stay forever.
# A pruned card's Regrade falls back to asking for the photo, exactly as a
# card graded before images were stored does.
# Counted from created_at, which update_grade_result bumps — so a card you
# regraded yesterday keeps its photos for another week, rather than being
# pruned on the age of its first grading.
# 0 or negative disables pruning entirely.
SOURCE_IMAGE_RETENTION_DAYS = int(
    os.environ.get("CARD_GRADER_IMAGE_RETENTION_DAYS", "7"))


def connect():
    # timeout: how long to wait for a writer's lock before giving up. The
    # server is threaded, so two people grading at once genuinely collide —
    # and since a row now carries the original photos, a write can be
    # several megabytes and hold the lock long enough to matter. The 5s
    # default was chosen for small writes; this isn't that any more.
    conn = sqlite3.connect(DB_PATH, timeout=30.0)
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA foreign_keys = ON")
    # WAL lets readers carry on during a write instead of blocking on it,
    # which is the difference between "someone else is grading" being
    # invisible and it freezing everyone's History. Persists on the database
    # file itself, so setting it per-connection is just belt-and-braces.
    conn.execute("PRAGMA journal_mode = WAL")
    conn.execute("PRAGMA synchronous = NORMAL")
    return conn


def init():
    conn = connect()
    try:
        conn.executescript(SCHEMA)
        # CREATE TABLE IF NOT EXISTS never touches an already-existing table,
        # so a column added after cards were already graded needs its own
        # migration — guarded because re-running this against a database
        # that already has the column would otherwise error every startup.
        for statement in (
            "ALTER TABLE grades ADD COLUMN aspect_measurement_json TEXT",
            "ALTER TABLE grades ADD COLUMN source_images_json TEXT",
        ):
            try:
                conn.execute(statement)
            except sqlite3.OperationalError:
                pass
        for key, value in DEFAULT_SETTINGS.items():
            conn.execute(
                "INSERT OR IGNORE INTO settings (key, value) VALUES (?, ?)",
                (key, json.dumps(value)),
            )
        conn.commit()
    finally:
        conn.close()


def now():
    return time.strftime("%Y-%m-%dT%H:%M:%S")


# --------------------------------------------------------------- settings


def get_settings():
    conn = connect()
    try:
        rows = conn.execute("SELECT key, value FROM settings").fetchall()
    finally:
        conn.close()
    out = dict(DEFAULT_SETTINGS)
    for row in rows:
        try:
            out[row["key"]] = json.loads(row["value"])
        except (ValueError, TypeError):
            out[row["key"]] = row["value"]
    return out


def save_settings(updates):
    conn = connect()
    try:
        for key, value in updates.items():
            if key not in DEFAULT_SETTINGS:
                continue
            conn.execute(
                "INSERT INTO settings (key, value) VALUES (?, ?) "
                "ON CONFLICT(key) DO UPDATE SET value=excluded.value",
                (key, json.dumps(value)),
            )
        conn.commit()
    finally:
        conn.close()
    return get_settings()


# ------------------------------------------------------------------ grades


def _encode_images(images):
    """(bytes, filename) pairs -> the JSON text stored in source_images_json."""
    if not images:
        return None
    return json.dumps([
        {"filename": name, "image_base64": base64.standard_b64encode(b).decode("ascii")}
        for b, name in images
    ])


def _decode_images(raw):
    if not raw:
        return None
    try:
        items = json.loads(raw)
    except (ValueError, TypeError):
        return None
    return [(base64.standard_b64decode(item["image_base64"]), item.get("filename") or "upload")
            for item in items]


def save_grade(grade, thumbnail=None, label=None, source_images=None):
    """Persist one grading result. Returns the new row's id.

    `source_images` are the original (bytes, filename) pairs that produced
    this grade, kept so Regrade can re-run without asking for the photo(s)
    again. Optional — a caller that skips this still gets everything else;
    Regrade just falls back to prompting for photos on that row.
    """
    conn = connect()
    try:
        cur = conn.execute(
            "INSERT INTO grades "
            "(created_at, label, card_type, card_note, image_count, thumbnail, "
            " model, estimated_grade, "
            " grade_low, grade_high, confidence, categories_json, "
            " edge_measurements_json, centering_measurement_json, "
            " aspect_measurement_json, "
            " limitations_json, note, estimated_cost, usage_json, "
            " source_images_json) "
            "VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)",
            (
                now(), label, grade.get("card_type"), grade.get("card_note"),
                grade.get("image_count"), thumbnail,
                (grade.get("usage") or {}).get("model"),
                grade.get("estimated_grade"), grade.get("grade_low"),
                grade.get("grade_high"), grade.get("confidence"),
                json.dumps(grade.get("categories")),
                json.dumps(grade.get("edge_measurements")),
                json.dumps(grade.get("centering_measurement")),
                json.dumps(grade.get("aspect_measurement")),
                json.dumps(grade.get("limitations")),
                grade.get("note"), grade.get("estimated_cost"),
                json.dumps(grade.get("usage")),
                _encode_images(source_images),
            ),
        )
        conn.commit()
        return cur.lastrowid
    finally:
        conn.close()


def update_grade_result(grade_id, grade, thumbnail=None, source_images=None):
    """Overwrite a grade's result in place (Regrade) — label is untouched.

    created_at is bumped to now, so the card floats back to the top of
    History as the most recently-active one, same as if it were freshly
    graded. `source_images` only overwrites the stored photo(s) when the
    caller actually supplies new ones (the re-pick fallback path); passing
    None leaves whatever was already stored for this row alone.
    """
    conn = connect()
    try:
        params = [
            now(), grade.get("card_type"), grade.get("card_note"),
            grade.get("image_count"),
            (grade.get("usage") or {}).get("model"),
            grade.get("estimated_grade"), grade.get("grade_low"),
            grade.get("grade_high"), grade.get("confidence"),
            json.dumps(grade.get("categories")),
            json.dumps(grade.get("edge_measurements")),
            json.dumps(grade.get("centering_measurement")),
            json.dumps(grade.get("aspect_measurement")),
            json.dumps(grade.get("limitations")),
            grade.get("note"), grade.get("estimated_cost"),
            json.dumps(grade.get("usage")),
        ]
        sql = (
            "UPDATE grades SET created_at=?, card_type=?, card_note=?, "
            "image_count=?, model=?, estimated_grade=?, grade_low=?, "
            "grade_high=?, confidence=?, categories_json=?, "
            "edge_measurements_json=?, centering_measurement_json=?, "
            "aspect_measurement_json=?, limitations_json=?, note=?, "
            "estimated_cost=?, usage_json=?"
        )
        if thumbnail is not None:
            sql += ", thumbnail=?"
            params.append(thumbnail)
        if source_images is not None:
            sql += ", source_images_json=?"
            params.append(_encode_images(source_images))
        sql += " WHERE id=?"
        params.append(grade_id)
        conn.execute(sql, params)
        conn.commit()
    finally:
        conn.close()
    return get_grade(grade_id)


def prune_source_images(days=None):
    """Drop stored photos older than the retention window. Returns the count.

    Only source_images_json is cleared — the grade, its thumbnail and its
    measurements are untouched, so history stays complete and only the
    expensive part expires.

    VACUUM afterwards because clearing a column returns its pages to
    SQLite's freelist without shrinking the file: without it the database
    would keep every byte this is meant to reclaim, and the whole feature
    would silently do nothing to disk usage. It rewrites the file, so it's
    run only when something was actually pruned, and on its own connection
    since VACUUM cannot execute inside a transaction.
    """
    days = SOURCE_IMAGE_RETENTION_DAYS if days is None else days
    if days <= 0:
        return 0
    cutoff = time.strftime("%Y-%m-%dT%H:%M:%S",
                           time.localtime(time.time() - days * 86400))
    conn = connect()
    try:
        cur = conn.execute(
            "UPDATE grades SET source_images_json = NULL "
            "WHERE source_images_json IS NOT NULL AND created_at < ?",
            (cutoff,),
        )
        pruned = cur.rowcount or 0
        conn.commit()
    finally:
        conn.close()

    if pruned:
        vac = sqlite3.connect(DB_PATH, timeout=60.0, isolation_level=None)
        try:
            vac.execute("VACUUM")
        finally:
            vac.close()
    return pruned


def get_grade_images(grade_id):
    """The original (bytes, filename) pairs for Regrade, or None if this
    grade never had them stored (a card graded before this feature existed,
    or one saved without the images path). Server-side use only — never
    sent to the browser, unlike everything get_grade/list_grades return."""
    conn = connect()
    try:
        row = conn.execute(
            "SELECT source_images_json FROM grades WHERE id = ?", (grade_id,)
        ).fetchone()
    finally:
        conn.close()
    return _decode_images(row["source_images_json"]) if row else None


def _row_to_grade(row):
    d = dict(row)
    for key in ("categories_json", "edge_measurements_json",
                "centering_measurement_json", "aspect_measurement_json",
                "limitations_json", "usage_json"):
        out_key = key[:-len("_json")]
        raw = d.pop(key, None)
        try:
            d[out_key] = json.loads(raw) if raw else None
        except (ValueError, TypeError):
            d[out_key] = None
    # The raw photo(s) are only ever for the regrade endpoint to read
    # server-side (see get_grade_images) — swapping this for a boolean here
    # keeps every browser-facing response light, the same reason thumbnails
    # are pre-shrunk rather than sending the original photo for display.
    d["has_source_images"] = bool(d.pop("source_images_json", None))
    return d


# Every column except source_images_json — that one is only ever read
# through get_grade_images, so a plain SELECT * here would pull the full
# original photo(s) off disk for every row just to discard them a moment
# later in _row_to_grade, silently defeating the whole point of keeping
# list/detail responses light.
_LIST_COLUMNS = (
    "id, created_at, label, card_type, card_note, image_count, thumbnail, "
    "model, estimated_grade, grade_low, grade_high, confidence, "
    "categories_json, edge_measurements_json, centering_measurement_json, "
    "aspect_measurement_json, limitations_json, note, estimated_cost, "
    "usage_json, (source_images_json IS NOT NULL) AS source_images_json"
)


def list_grades(limit=200):
    conn = connect()
    try:
        rows = conn.execute(
            "SELECT {} FROM grades ORDER BY created_at DESC, id DESC LIMIT ?"
            .format(_LIST_COLUMNS),
            (limit,),
        ).fetchall()
    finally:
        conn.close()
    return [_row_to_grade(r) for r in rows]


def get_grade(grade_id):
    conn = connect()
    try:
        row = conn.execute(
            "SELECT {} FROM grades WHERE id = ?".format(_LIST_COLUMNS),
            (grade_id,),
        ).fetchone()
    finally:
        conn.close()
    return _row_to_grade(row) if row else None


def update_grade_label(grade_id, label):
    conn = connect()
    try:
        conn.execute("UPDATE grades SET label = ? WHERE id = ?", (label, grade_id))
        conn.commit()
    finally:
        conn.close()
    return get_grade(grade_id)


def delete_grade(grade_id):
    conn = connect()
    try:
        conn.execute("DELETE FROM grades WHERE id = ?", (grade_id,))
        conn.commit()
    finally:
        conn.close()