"""
Database schema and models for KikoTextEncode prompt storage.
"""

import contextlib
import datetime
import json
import math
import sqlite3
import os
import threading
import tempfile
import weakref
from contextlib import closing
from pathlib import Path
from typing import Optional, Set, Tuple

from .library_schema import library_schema_error, migrate_library_state
from .image_favorites import image_favorites_schema_error, migrate_image_favorites
from .execution_history_schema import (
    history_schema_error,
    migrate_execution_history,
    rotate_history_epoch,
)

# Import logging system
try:
    from ..utils.logging_config import get_logger
except ImportError:
    import sys

    current_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
    sys.path.insert(0, current_dir)
    from utils.logging_config import get_logger

# last_used_at is UTC ISO text so ORDER BY can compare it as text. The backfill
# writes milliseconds (SQLite's %f); live writes use microseconds so runs in the
# same millisecond still order correctly. Both forms sort correctly together.
ISO_TIMESTAMP_FORMAT = "%Y-%m-%dT%H:%M:%f+00:00"


MAX_PAIR_PROVENANCE_LENGTH = 4_000_000
MAX_PAIR_PROVENANCE_DEPTH = 64


def pair_provenance_error(encoded: object) -> Optional[str]:
    """Validate the same bounded JSON object for live writes and restores."""
    if not isinstance(encoded, str):
        return "Pair provenance must be JSON text"
    if len(encoded) > MAX_PAIR_PROVENANCE_LENGTH:
        return "Pair provenance exceeds the size limit"
    try:
        value = json.loads(encoded)
    except (ValueError, TypeError, RecursionError):
        return "Pair provenance is not readable JSON"
    if not isinstance(value, dict):
        return "Pair provenance must be a JSON object"
    pending = [(iter((value,)), 0)]
    while pending:
        children, depth = pending[-1]
        try:
            item = next(children)
        except StopIteration:
            pending.pop()
            continue
        if depth > MAX_PAIR_PROVENANCE_DEPTH:
            return "Pair provenance exceeds the nesting limit"
        if isinstance(item, float) and not math.isfinite(item):
            return "Pair provenance contains nonfinite numbers"
        if isinstance(item, dict):
            pending.append((iter(item.values()), depth + 1))
        elif isinstance(item, list):
            pending.append((iter(item), depth + 1))
    return None


def utc_now_iso() -> str:
    """Current UTC time as ISO text with microseconds.

    Example: 2026-10-07T18:39:06.758123+00:00
    """
    return datetime.datetime.now(datetime.timezone.utc).isoformat(
        timespec="microseconds"
    )


def normalize_image_path(path: str) -> str:
    """Canonical form of an image path for generated_images.file_path.

    Absolute, with '..' and '.' collapsed and the platform's case folding
    applied, so two spellings of one file (or the same basename in two date
    folders) compare the way the filesystem would.
    """
    return os.path.normcase(os.path.normpath(os.path.abspath(path)))


# How long a connection waits for a locked database before giving up. Thirty
# seconds covers a scan or a thumbnail run writing while ComfyUI saves images,
# and the slow disks of CI runners.
BUSY_TIMEOUT_SECONDS = 30
SQLITE_HEADER = b"SQLite format 3\x00"
REQUIRED_PROMPT_COLUMNS = ("id", "text", "created_at")


def configure_connection(conn: sqlite3.Connection) -> None:
    """Apply the locking and durability settings every managed connection shares.

    WAL lets readers run beside the single writer. In WAL mode
    ``synchronous=NORMAL`` keeps the database consistent after an application
    or ComfyUI crash and flushes only at checkpoints, so a commit no longer
    holds SQLite's write lock across a disk flush. Under ``FULL`` a slow flush
    (common on Windows) let other writers' polling busy handlers starve past
    BUSY_TIMEOUT_SECONDS and fail with "database is locked" (#242). Without
    WAL (for example an in-memory database) SQLite's FULL default is kept.
    """
    journal_mode = conn.execute("PRAGMA journal_mode = WAL").fetchone()[0]
    conn.execute("PRAGMA foreign_keys = ON")
    conn.execute(f"PRAGMA busy_timeout = {BUSY_TIMEOUT_SECONDS * 1000}")
    if str(journal_mode).lower() == "wal":
        conn.execute("PRAGMA synchronous = NORMAL")


class PromptModel:
    """Database model for prompt storage and schema management."""

    # Paths (normalised, see _schema_key) whose schema has been created and
    # migrated in this process. Many PromptDatabase instances point at the
    # same file; only the first one pays for the schema check.
    _initialized_paths: Set[str] = set()
    _init_lock = threading.Lock()
    # Every live model, so a shutdown or a test teardown can close them all
    # before the database file is deleted (Windows refuses otherwise).
    _instances: "weakref.WeakSet[PromptModel]" = weakref.WeakSet()
    _instances_lock = threading.Lock()

    def __init__(self, db_path: str):
        """
        Initialize the database model.

        Args:
            db_path: Absolute path to the SQLite database file
        """
        self.logger = get_logger("prompt_manager.database.models")
        self.logger.debug(f"Initializing database model with path: {db_path}")
        self.db_path = db_path
        # One connection per thread (see get_connection); every open connection
        # is also tracked here so close_all can clean up across threads.
        self._local = threading.local()
        self._connections: Set[sqlite3.Connection] = set()
        self._conn_lock = threading.Lock()
        # Bumped by _close_all_connections so threads holding a closed
        # connection reopen on their next get_connection().
        self._generation = 0
        with PromptModel._instances_lock:
            PromptModel._instances.add(self)
        self._ensure_database_exists()

    def _ensure_database_exists(self) -> None:
        """
        Create database and tables if they don't exist.

        Sets up the database schema including tables for prompts and generated images,
        creates necessary indexes, and applies any pending migrations.

        Raises:
            Exception: If database creation fails
        """
        key = self._schema_key()
        with PromptModel._init_lock:
            if key in PromptModel._initialized_paths and os.path.exists(self.db_path):
                return
            try:
                conn = sqlite3.connect(self.db_path, timeout=BUSY_TIMEOUT_SECONDS)
                try:
                    configure_connection(conn)
                    self._create_tables(conn)
                    self._create_indexes(conn)
                    conn.commit()
                finally:
                    conn.close()
            except Exception as e:
                self.logger.error(f"Error creating database: {e}")
                raise
            PromptModel._initialized_paths.add(key)

    def _schema_key(self) -> str:
        """Normalised identity of db_path for the once-per-process schema cache."""
        return os.path.normcase(os.path.realpath(self.db_path))

    @classmethod
    def reset_schema_cache(cls) -> None:
        """Forget which databases were initialised (tests and restores)."""
        with cls._init_lock:
            cls._initialized_paths.clear()

    @contextlib.contextmanager
    def _table_rebuild(self, conn: sqlite3.Connection):
        """Run a copy-and-swap table rebuild with foreign keys disabled.

        DROP TABLE on a parent table with foreign_keys ON performs an implicit
        DELETE that cascades into child rows (generated_images, prompt_tags),
        so the rebuild runs with the pragma off. The pragma is a no-op inside
        a transaction, hence the commits around it. Errors roll back and
        propagate after the pragma is restored.
        """
        conn.commit()
        conn.execute("PRAGMA foreign_keys = OFF")
        # Explicit BEGIN: in sqlite3's legacy transaction mode DDL autocommits,
        # so without it a failed copy would leave the *_new table behind.
        conn.execute("BEGIN")
        try:
            yield
            conn.commit()
        except BaseException:
            conn.rollback()
            raise
        finally:
            conn.execute("PRAGMA foreign_keys = ON")

    def _create_tables(self, conn: sqlite3.Connection) -> None:
        """
        Create the prompts and generated_images tables with all required columns.

        Args:
            conn: Active database connection

        Creates:
            - prompts table: Stores prompt text and metadata
            - generated_images table: Links generated images to their source prompts
        """
        conn.execute("""
            CREATE TABLE IF NOT EXISTS prompts (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                text TEXT NOT NULL,
                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                category TEXT,
                tags TEXT,
                rating INTEGER CHECK(rating >= 1 AND rating <= 5),
                notes TEXT,
                hash TEXT UNIQUE,
                last_used_at TIMESTAMP,
                run_count INTEGER NOT NULL DEFAULT 0
            )
        """)

        # Create images table for gallery functionality
        conn.execute("""
            CREATE TABLE IF NOT EXISTS generated_images (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                prompt_id INTEGER NOT NULL,
                image_path TEXT NOT NULL,
                filename TEXT NOT NULL,
                generation_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                file_size INTEGER,
                width INTEGER,
                height INTEGER,
                format TEXT,
                workflow_data TEXT,
                prompt_metadata TEXT,
                parameters TEXT,
                file_path TEXT,
                FOREIGN KEY (prompt_id) REFERENCES prompts(id) ON DELETE CASCADE,
                UNIQUE(prompt_id, file_path)
            )
        """)

        # Create normalized tag tables (junction table pattern)
        conn.execute("""
            CREATE TABLE IF NOT EXISTS tags (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                name TEXT NOT NULL UNIQUE
            )
        """)
        conn.execute("""
            CREATE TABLE IF NOT EXISTS prompt_tags (
                prompt_id INTEGER NOT NULL,
                tag_id INTEGER NOT NULL,
                PRIMARY KEY (prompt_id, tag_id),
                FOREIGN KEY (prompt_id) REFERENCES prompts(id) ON DELETE CASCADE,
                FOREIGN KEY (tag_id) REFERENCES tags(id) ON DELETE CASCADE
            )
        """)

        # Check if we need to migrate from old schema with workflow_name
        self._migrate_workflow_name_removal(conn)

        # Fix foreign key data type mismatch
        self._migrate_foreign_key_types(conn)

        # Migrate JSON tags to normalized junction tables
        self._migrate_json_tags_to_junction(conn)

        # Usage tracking columns (after any migration that rebuilds prompts)
        self._migrate_add_usage_columns(conn)

        # Image uniqueness by full path instead of basename (3.2.4)
        self._migrate_image_uniqueness_by_path(conn)
        self._migrate_prompt_pairs(conn)
        migrate_execution_history(conn)
        migrate_library_state(conn)
        migrate_image_favorites(conn)

    def _migrate_prompt_pairs(self, conn: sqlite3.Connection) -> None:
        conn.execute("SAVEPOINT prompt_pair_schema")
        try:
            conn.execute("""
                CREATE TABLE IF NOT EXISTS prompt_pairs (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    positive_prompt_id INTEGER NOT NULL,
                    negative_prompt_id INTEGER,
                    title TEXT,
                    category TEXT,
                    rating INTEGER CHECK(rating BETWEEN 1 AND 5),
                    notes TEXT,
                    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
                    updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
                    last_used_at TEXT,
                    run_count INTEGER NOT NULL DEFAULT 0,
                    archived INTEGER NOT NULL DEFAULT 0 CHECK(archived IN (0, 1)),
                    FOREIGN KEY(positive_prompt_id)
                        REFERENCES prompts(id) ON DELETE RESTRICT,
                    FOREIGN KEY(negative_prompt_id)
                        REFERENCES prompts(id) ON DELETE RESTRICT,
                    UNIQUE(positive_prompt_id, negative_prompt_id)
                )
            """)
            conn.execute("""
                CREATE TABLE IF NOT EXISTS prompt_pair_tags (
                    pair_id INTEGER NOT NULL,
                    tag_id INTEGER NOT NULL,
                    PRIMARY KEY(pair_id, tag_id),
                    FOREIGN KEY(pair_id) REFERENCES prompt_pairs(id) ON DELETE CASCADE,
                    FOREIGN KEY(tag_id) REFERENCES tags(id) ON DELETE CASCADE
                )
            """)
            conn.execute("""
                CREATE TABLE IF NOT EXISTS image_prompt_pairs (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    image_id INTEGER NOT NULL,
                    pair_id INTEGER NOT NULL,
                    provenance TEXT NOT NULL,
                    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
                    FOREIGN KEY(image_id)
                        REFERENCES generated_images(id) ON DELETE CASCADE,
                    FOREIGN KEY(pair_id) REFERENCES prompt_pairs(id) ON DELETE RESTRICT,
                    UNIQUE(pair_id, image_id, provenance)
                )
            """)
            self._create_pair_indexes(conn)
            error = self._pair_schema_error(conn)
            if error:
                raise sqlite3.DatabaseError(error)
            conn.execute("RELEASE prompt_pair_schema")
        except BaseException:
            conn.execute("ROLLBACK TO prompt_pair_schema")
            conn.execute("RELEASE prompt_pair_schema")
            raise

    @staticmethod
    def _create_pair_indexes(conn: sqlite3.Connection) -> None:
        conn.execute(
            "CREATE UNIQUE INDEX IF NOT EXISTS idx_prompt_pairs_positive_only "
            "ON prompt_pairs(positive_prompt_id) WHERE negative_prompt_id IS NULL"
        )
        for name, target in (
            ("idx_prompt_pairs_negative", "prompt_pairs(negative_prompt_id)"),
            ("idx_prompt_pair_tags_tag", "prompt_pair_tags(tag_id)"),
            ("idx_image_prompt_pairs_image", "image_prompt_pairs(image_id)"),
        ):
            conn.execute(f"CREATE INDEX IF NOT EXISTS {name} ON {target}")

    @staticmethod
    def _pair_schema_error(conn: sqlite3.Connection) -> Optional[str]:
        required = {
            "prompt_pairs": {
                "id",
                "positive_prompt_id",
                "negative_prompt_id",
                "title",
                "category",
                "rating",
                "notes",
                "created_at",
                "updated_at",
                "last_used_at",
                "run_count",
                "archived",
            },
            "prompt_pair_tags": {"pair_id", "tag_id"},
            "image_prompt_pairs": {
                "id",
                "image_id",
                "pair_id",
                "provenance",
                "created_at",
            },
        }
        present = {
            row[0]
            for row in conn.execute("SELECT name FROM sqlite_master WHERE type='table'")
        }
        if not present.intersection(required):
            return None
        if not set(required).issubset(present):
            return "Incomplete prompt pair schema"
        foreign_keys = {
            "prompt_pairs": {
                ("positive_prompt_id", "prompts", "id", "RESTRICT"),
                ("negative_prompt_id", "prompts", "id", "RESTRICT"),
            },
            "prompt_pair_tags": {
                ("pair_id", "prompt_pairs", "id", "CASCADE"),
                ("tag_id", "tags", "id", "CASCADE"),
            },
            "image_prompt_pairs": {
                ("pair_id", "prompt_pairs", "id", "RESTRICT"),
                ("image_id", "generated_images", "id", "CASCADE"),
            },
        }
        unique = {
            "prompt_pairs": ("positive_prompt_id", "negative_prompt_id"),
            "prompt_pair_tags": ("pair_id", "tag_id"),
            "image_prompt_pairs": ("pair_id", "image_id", "provenance"),
        }
        non_null = {
            "prompt_pairs": {
                "positive_prompt_id",
                "created_at",
                "updated_at",
                "run_count",
                "archived",
            },
            "prompt_pair_tags": {"pair_id", "tag_id"},
            "image_prompt_pairs": {"pair_id", "image_id", "provenance", "created_at"},
        }
        integer_columns = {
            "id",
            "positive_prompt_id",
            "negative_prompt_id",
            "pair_id",
            "tag_id",
            "image_id",
            "rating",
            "run_count",
            "archived",
        }
        for table, columns in required.items():
            info = {row[1]: row for row in conn.execute(f"PRAGMA table_info({table})")}
            if not columns.issubset(info):
                return f"{table} is missing required pair columns"
            if any(not info[name][3] for name in non_null[table]):
                return f"{table} has nullable required pair columns"
            if any(
                info[name][2].upper()
                != ("INTEGER" if name in integer_columns else "TEXT")
                for name in columns
            ):
                return f"{table} has invalid pair column types"
            primary = tuple(
                name
                for name in sorted(info, key=lambda name: info[name][5])
                if info[name][5]
            )
            if primary != (
                ("pair_id", "tag_id") if table == "prompt_pair_tags" else ("id",)
            ):
                return f"{table} has an invalid pair primary key"
            actual_fks = {
                (row[3], row[2], row[4], row[6])
                for row in conn.execute(f"PRAGMA foreign_key_list({table})")
            }
            if actual_fks != foreign_keys[table]:
                return f"{table} has invalid pair foreign key definitions"
            if conn.execute(f"PRAGMA foreign_key_check({table})").fetchone():
                return f"{table} contains foreign key violations"
            indexes = list(conn.execute(f"PRAGMA index_list({table})"))
            index_columns = {}
            for row in indexes:
                name = row[1].replace('"', '""')
                index_columns[row[1]] = tuple(
                    item[2] for item in conn.execute(f'PRAGMA index_info("{name}")')
                )
            if not any(
                row[2] and not row[4] and index_columns[row[1]] == unique[table]
                for row in indexes
            ):
                return f"{table} is missing pair uniqueness constraints"
            if table == "prompt_pairs":
                null_unique = False
                for row in indexes:
                    if (
                        row[2]
                        and row[4]
                        and index_columns[row[1]] == ("positive_prompt_id",)
                    ):
                        sql = conn.execute(
                            "SELECT sql FROM sqlite_master WHERE type='index' AND name"
                            "=?",
                            (row[1],),
                        ).fetchone()[0]
                        if " ".join(sql.lower().split()).endswith(
                            "where negative_prompt_id is null"
                        ):
                            null_unique = True
                if not null_unique:
                    return "prompt_pairs is missing empty-negative pair uniqueness"
        if conn.execute(
            "SELECT 1 FROM image_prompt_pairs ip "
            "JOIN prompt_pairs pp ON pp.id=ip.pair_id "
            "JOIN generated_images gi ON gi.id=ip.image_id "
            "WHERE pp.positive_prompt_id IS NOT gi.prompt_id LIMIT 1"
        ).fetchone():
            return "Image pair association has a different positive prompt owner"
        for row in conn.execute("SELECT provenance FROM image_prompt_pairs"):
            error = pair_provenance_error(row[0])
            if error:
                return error
        return None

    def _create_indexes(self, conn: sqlite3.Connection) -> None:
        """
        Create indexes for better query performance.

        Args:
            conn: Active database connection

        Creates indexes on:
            - Text content for search operations
            - Categories and tags for filtering
            - Timestamps for sorting
            - Hash values for duplicate detection
        """
        indexes = [
            ("idx_prompts_text", "prompts(text)"),
            ("idx_prompts_category", "prompts(category)"),
            ("idx_prompts_created_at", "prompts(created_at)"),
            ("idx_prompts_hash", "prompts(hash)"),
            ("idx_prompts_rating", "prompts(rating)"),
            ("idx_prompts_last_used", "prompts(last_used_at)"),
            ("idx_prompts_run_count", "prompts(run_count)"),
            ("idx_prompt_images", "generated_images(prompt_id)"),
            ("idx_image_path", "generated_images(image_path)"),
            ("idx_image_file_path", "generated_images(file_path)"),
            ("idx_generation_time", "generated_images(generation_time)"),
            ("idx_prompt_tags_tag", "prompt_tags(tag_id)"),
            ("idx_tags_name", "tags(name)"),
        ]

        for name, target in indexes:
            conn.execute(f"CREATE INDEX IF NOT EXISTS {name} ON {target}")

    def get_connection(self) -> sqlite3.Connection:
        """
        Get the calling thread's database connection.

        Each thread gets its own ``sqlite3.Connection`` (kept in
        ``threading.local``), created on first use and reused by that thread
        thereafter. Every connection gets ``row_factory = sqlite3.Row`` and the
        shared settings of ``configure_connection``: WAL journaling with
        ``synchronous=NORMAL``, ``PRAGMA foreign_keys = ON`` and a
        ``busy_timeout`` of BUSY_TIMEOUT_SECONDS so concurrent writers wait
        instead of failing. Callers use it as a context manager
        (``with conn:``), which commits or rolls back that thread's transaction
        and leaves the connection open. No lock is held while a connection is in use.

        Returns:
            sqlite3.Connection: The current thread's configured connection
        """
        conn = getattr(self._local, "conn", None)
        if conn is not None and self._local.generation == self._generation:
            return conn

        # check_same_thread=False only so close_all can clean up other
        # threads' connections; each connection is still used by one thread.
        conn = sqlite3.connect(
            self.db_path, check_same_thread=False, timeout=BUSY_TIMEOUT_SECONDS
        )
        conn.row_factory = sqlite3.Row
        configure_connection(conn)
        self._local.conn = conn
        self._local.generation = self._generation
        with self._conn_lock:
            self._connections.add(conn)
        return conn

    @classmethod
    def close_all_instances(cls) -> None:
        """Close every connection of every live model in this process."""
        with cls._instances_lock:
            models = list(cls._instances)
        for model in models:
            model.close_all()

    def close_all(self) -> None:
        """Close every thread's connection; they reopen lazily on next use.

        Needed before deleting the database file (Windows keeps open files
        locked) and by tests that ran queries through executor threads.
        """
        with self._conn_lock:
            connections = list(self._connections)
            self._connections.clear()
            self._generation += 1
        self._local.conn = None
        for conn in connections:
            try:
                conn.close()
            except sqlite3.Error as e:
                self.logger.warning(f"Error closing database connection: {e}")

    def close(self) -> None:
        """Close the calling thread's connection, if it has one.

        Other threads keep their connections. Call this before deleting or
        replacing the database file: Windows refuses to delete an open file.
        """
        conn = getattr(self._local, "conn", None)
        if conn is None:
            return
        self._local.conn = None
        with self._conn_lock:
            self._connections.discard(conn)
        try:
            conn.close()
        except sqlite3.Error as e:
            self.logger.warning(f"Error closing database connection: {e}")

    def _migrate_workflow_name_removal(self, conn: sqlite3.Connection) -> None:
        """
        Remove workflow_name column if it exists in existing database.

        Args:
            conn: Active database connection

        This migration handles legacy schema updates by removing the deprecated
        workflow_name column while preserving all other data.

        Raises:
            sqlite3.Error: If the rebuild fails (logged, nothing half-applied)
        """
        try:
            cursor = conn.execute("PRAGMA table_info(prompts)")
            columns = [column[1] for column in cursor.fetchall()]
            if "workflow_name" not in columns:
                return

            self.logger.info("Migrating database: removing workflow_name column")
            with self._table_rebuild(conn):
                # A previous attempt may have died between CREATE and RENAME
                conn.execute("DROP TABLE IF EXISTS prompts_new")
                conn.execute("""
                    CREATE TABLE prompts_new (
                        id INTEGER PRIMARY KEY AUTOINCREMENT,
                        text TEXT NOT NULL,
                        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                        updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                        category TEXT,
                        tags TEXT,
                        rating INTEGER CHECK(rating >= 1 AND rating <= 5),
                        notes TEXT,
                        hash TEXT UNIQUE
                    )
                """)
                conn.execute("""
                    INSERT INTO prompts_new (id, text, created_at, updated_at,
                        category, tags, rating, notes, hash)
                    SELECT id, text, created_at, updated_at, category, tags, rating,
                        notes, hash
                    FROM prompts
                """)
                conn.execute("DROP TABLE prompts")
                conn.execute("ALTER TABLE prompts_new RENAME TO prompts")
            self.logger.info("Database migration completed")

        except sqlite3.Error as e:
            self.logger.error(f"Migration error (workflow_name removal): {e}")
            raise

    def _migrate_foreign_key_types(self, conn: sqlite3.Connection) -> None:
        """
        Fix foreign key data type mismatch in generated_images table.

        Args:
            conn: Active database connection

        Converts prompt_id from TEXT to INTEGER type to match the prompts table's
        primary key type, ensuring referential integrity.

        Raises:
            sqlite3.Error: If the rebuild fails (logged, nothing half-applied)
        """
        try:
            cursor = conn.execute("PRAGMA table_info(generated_images)")
            columns = {column[1]: column[2] for column in cursor.fetchall()}
            if columns.get("prompt_id") != "TEXT":
                return

            self.logger.info("Migrating foreign key types: prompt_id TEXT -> INTEGER")
            with self._table_rebuild(conn):
                conn.execute("DROP TABLE IF EXISTS generated_images_new")
                conn.execute("""
                    CREATE TABLE generated_images_new (
                        id INTEGER PRIMARY KEY AUTOINCREMENT,
                        prompt_id INTEGER NOT NULL,
                        image_path TEXT NOT NULL,
                        filename TEXT NOT NULL,
                        generation_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                        file_size INTEGER,
                        width INTEGER,
                        height INTEGER,
                        format TEXT,
                        workflow_data TEXT,
                        prompt_metadata TEXT,
                        parameters TEXT,
                        FOREIGN KEY (prompt_id) REFERENCES prompts(id) ON DELETE CASCADE
                    )
                """)
                conn.execute("""
                    INSERT INTO generated_images_new
                    (id, prompt_id, image_path, filename, generation_time, file_size,
                     width, height, format, workflow_data, prompt_metadata, parameters)
                    SELECT id, CAST(prompt_id AS INTEGER), image_path, filename,
                        generation_time,
                           file_size, width, height, format, workflow_data,
                               prompt_metadata, parameters
                    FROM generated_images
                    WHERE prompt_id != '' AND prompt_id IS NOT NULL
                    AND CAST(prompt_id AS INTEGER) IN (SELECT id FROM prompts)
                """)
                conn.execute("DROP TABLE generated_images")
                conn.execute(
                    "ALTER TABLE generated_images_new RENAME TO generated_images"
                )
            self.logger.info("Foreign key migration completed")

        except sqlite3.Error as e:
            self.logger.error(f"Migration error (foreign key types): {e}")
            raise

    def _migrate_json_tags_to_junction(self, conn: sqlite3.Connection) -> None:
        """
        Populate tags and prompt_tags tables from legacy JSON tags column.

        Runs once: skips if the tags table already has data. Uses json_each()
        to extract tag names from the JSON arrays stored in prompts.tags.

        Raises:
            sqlite3.Error: If the migration fails (logged)
        """
        try:
            cursor = conn.execute("SELECT COUNT(*) FROM tags")
            if cursor.fetchone()[0] > 0:
                return  # Already migrated

            cursor = conn.execute(
                "SELECT COUNT(*) FROM prompts "
                "WHERE tags IS NOT NULL AND tags != '' AND tags != '[]'"
            )
            if cursor.fetchone()[0] == 0:
                return  # No tags to migrate

            self.logger.info("Migrating JSON tags to normalized junction tables")

            # Insert all unique tag names
            conn.execute(
                "INSERT OR IGNORE INTO tags (name) "
                "SELECT DISTINCT je.value FROM prompts, json_each(prompts.tags) AS je "
                "WHERE prompts.tags IS NOT NULL AND prompts.tags != '' AND "
                "prompts.tags != '[]'"
            )

            # Populate junction table
            conn.execute(
                "INSERT OR IGNORE INTO prompt_tags (prompt_id, tag_id) "
                "SELECT p.id, t.id "
                "FROM prompts p, json_each(p.tags) AS je "
                "JOIN tags t ON t.name = je.value "
                "WHERE p.tags IS NOT NULL AND p.tags != '' AND p.tags != '[]'"
            )

            tag_count = conn.execute("SELECT COUNT(*) FROM tags").fetchone()[0]
            link_count = conn.execute("SELECT COUNT(*) FROM prompt_tags").fetchone()[0]
            self.logger.info(
                f"Tag migration complete: {tag_count} unique tags, {link_count} "
                "prompt-tag links"
            )

        except sqlite3.Error as e:
            self.logger.error(f"Migration error (tag junction): {e}")
            raise

    def _migrate_add_usage_columns(self, conn: sqlite3.Connection) -> None:
        """
        Add last_used_at and run_count (3.2.4) and estimate usage for existing rows.

        The backfill runs only when the columns are added, i.e. on the upgrade
        from a version without usage tracking. Afterwards a NULL last_used_at
        means "never run": saving a prompt does not stamp it, only
        record_prompt_use does, and "Recently Used" relies on that.

        The estimate comes from linked images: run_count is the image count (at
        least 1) and last_used_at the newest image time, falling back to created_at.
        Timestamps are compared with julianday() because prompts use ISO 'T'
        timestamps while generated_images uses SQLite's CURRENT_TIMESTAMP format.
        """
        try:
            columns = {row[1] for row in conn.execute("PRAGMA table_info(prompts)")}
            added = False
            if "last_used_at" not in columns:
                self.logger.info("Adding prompt usage column last_used_at")
                conn.execute("ALTER TABLE prompts ADD COLUMN last_used_at TIMESTAMP")
                added = True
            if "run_count" not in columns:
                self.logger.info("Adding prompt usage column run_count")
                conn.execute(
                    "ALTER TABLE prompts ADD COLUMN run_count INTEGER NOT NULL "
                    "DEFAULT 0"
                )
                added = True
            if not added:
                return

            cursor = conn.execute(f"""
                UPDATE prompts SET
                    run_count = MAX(run_count, 1, (
                        SELECT COUNT(*) FROM generated_images gi
                        WHERE gi.prompt_id = prompts.id
                    )),
                    last_used_at = strftime('{ISO_TIMESTAMP_FORMAT}', MAX(
                        COALESCE(julianday(created_at), julianday('now')),
                        COALESCE((
                            SELECT MAX(julianday(gi.generation_time))
                            FROM generated_images gi WHERE gi.prompt_id = prompts.id
                        ), 0)
                    ))
                WHERE last_used_at IS NULL
            """)
            if cursor.rowcount:
                self.logger.info(f"Estimated usage for {cursor.rowcount} prompts")
        except sqlite3.Error as e:
            self.logger.error(f"Migration error (usage columns): {e}")
            raise

    def _migrate_image_uniqueness_by_path(self, conn: sqlite3.Connection) -> None:
        """
        Rebuild generated_images so an image is unique per (prompt_id, file_path).

        Older schemas were unique per (prompt_id, filename), i.e. the basename,
        so ComfyUI's same-named files in different date folders were silently
        dropped. file_path holds normalize_image_path(image_path); rows whose
        paths normalise to the same file collapse to the newest one.

        Raises:
            sqlite3.Error: If the rebuild fails (logged, nothing half-applied)
        """
        try:
            columns = {
                row[1] for row in conn.execute("PRAGMA table_info(generated_images)")
            }
            if "file_path" in columns:
                return

            self.logger.info("Migrating database: image uniqueness by full path")
            with self._table_rebuild(conn):
                rows = conn.execute(
                    "SELECT id, prompt_id, image_path FROM generated_images ORDER BY id"
                ).fetchall()
                keep = {}
                for row_id, prompt_id, image_path in rows:
                    keep[(prompt_id, normalize_image_path(image_path))] = row_id

                conn.execute("DROP TABLE IF EXISTS generated_images_new")
                conn.execute("""
                    CREATE TABLE generated_images_new (
                        id INTEGER PRIMARY KEY AUTOINCREMENT,
                        prompt_id INTEGER NOT NULL,
                        image_path TEXT NOT NULL,
                        filename TEXT NOT NULL,
                        generation_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                        file_size INTEGER,
                        width INTEGER,
                        height INTEGER,
                        format TEXT,
                        workflow_data TEXT,
                        prompt_metadata TEXT,
                        parameters TEXT,
                        file_path TEXT,
                        FOREIGN KEY (prompt_id) REFERENCES prompts(id) ON DELETE
                            CASCADE,
                        UNIQUE(prompt_id, file_path)
                    )
                """)
                conn.executemany(
                    """
                    INSERT INTO generated_images_new
                    (id, prompt_id, image_path, filename, generation_time, file_size,
                     width, height, format, workflow_data, prompt_metadata, parameters,
                     file_path)
                    SELECT id, prompt_id, image_path, filename, generation_time,
                        file_size,
                           width, height, format, workflow_data, prompt_metadata,
                               parameters,
                           ?
                    FROM generated_images WHERE id = ?
                    """,
                    [(file_path, row_id) for (_, file_path), row_id in keep.items()],
                )
                conn.execute("DROP TABLE generated_images")
                conn.execute(
                    "ALTER TABLE generated_images_new RENAME TO generated_images"
                )
            dropped = len(rows) - len(keep)
            if dropped:
                self.logger.info(f"Collapsed {dropped} duplicate image rows")
            self.logger.info("Image path uniqueness migration completed")

        except sqlite3.Error as e:
            self.logger.error(f"Migration error (image path uniqueness): {e}")
            raise

    def vacuum_database(self) -> None:
        """
        Optimize database by running VACUUM command.

        Reclaims unused space and defragments the database file,
        improving query performance and reducing file size.
        """
        try:
            with closing(sqlite3.connect(self.db_path)) as conn:
                conn.execute("VACUUM")
                conn.commit()
        except Exception as e:
            self.logger.error(f"Error vacuuming database: {e}")

    def get_database_info(self) -> dict:
        """
        Get information about the database.

        Returns:
            dict: Database statistics and information
        """
        try:
            with self.get_connection() as conn:
                cursor = conn.execute("SELECT COUNT(*) as total_prompts FROM prompts")
                total_prompts = cursor.fetchone()["total_prompts"]

                cursor = conn.execute(
                    "SELECT COUNT(DISTINCT category) as unique_categories FROM "
                    "prompts WHERE category IS NOT NULL"
                )
                unique_categories = cursor.fetchone()["unique_categories"]

                cursor = conn.execute(
                    "SELECT AVG(rating) as avg_rating FROM prompts WHERE rating IS "
                    "NOT NULL"
                )
                avg_rating = cursor.fetchone()["avg_rating"]

                # Get database file size
                db_size = (
                    os.path.getsize(self.db_path) if os.path.exists(self.db_path) else 0
                )

                return {
                    "total_prompts": total_prompts,
                    "unique_categories": unique_categories,
                    "average_rating": round(avg_rating, 2) if avg_rating else None,
                    "database_size_bytes": db_size,
                    "database_path": os.path.abspath(self.db_path),
                }
        except Exception as e:
            self.logger.error(f"Error getting database info: {e}")
            return {}

    def backup_database(self, backup_path: str) -> bool:
        """
        Write a consistent copy of the database to backup_path.

        Uses the SQLite online backup API through this thread's connection,
        so rows that are committed but still sit in the -wal file are
        included and other threads may keep reading and writing meanwhile.

        Args:
            backup_path: Path where the backup should be saved (overwritten)

        Returns:
            bool: True if backup was successful, False otherwise
        """
        try:
            if os.path.exists(backup_path) and os.path.samefile(
                backup_path, self.db_path
            ):
                self.logger.error("Refusing to back up the database onto itself")
                return False
            if os.path.exists(backup_path):
                os.remove(backup_path)
            source = self.get_connection()
            destination = sqlite3.connect(backup_path)
            try:
                source.backup(destination)
            finally:
                destination.close()
            return True
        except (OSError, sqlite3.Error) as e:
            self.logger.error(f"Error creating database backup: {e}")
            return False

    @staticmethod
    def verify_database_file(
        path: str, *, require_library_state: bool = False
    ) -> Tuple[bool, str]:
        """
        Check that a file is a healthy prompts database before restoring it.

        Opens the file read-only, runs PRAGMA integrity_check and confirms the
        prompts table has the columns every version of this extension needs.

        Args:
            path: File to inspect
            require_library_state: Also require the tables every current
                database has (Library state and image favorites), as a
                migrated restore stage must; old backups may lack them.

        Returns:
            (ok, reason): reason is "ok" when the file is acceptable, otherwise
            a human-readable explanation. Never raises for bad input.
        """
        if not os.path.isfile(path):
            return False, "File not found"
        try:
            with open(path, "rb") as fh:
                header = fh.read(len(SQLITE_HEADER))
        except OSError as e:
            return False, f"Cannot read file: {e}"
        if header != SQLITE_HEADER:
            return False, "Not a SQLite database file"

        uri = Path(os.path.abspath(path)).as_uri() + "?mode=ro"
        try:
            conn = sqlite3.connect(uri, uri=True)
        except sqlite3.Error as e:
            return False, f"Invalid SQLite database: {e}"
        try:
            row = conn.execute("PRAGMA integrity_check").fetchone()
            verdict = row[0] if row else "no result"
            if verdict != "ok":
                return False, f"Integrity check failed: {verdict}"
            table = conn.execute(
                "SELECT name FROM sqlite_master WHERE type='table' AND name='prompts'"
            ).fetchone()
            if not table:
                return False, "Database does not contain a 'prompts' table"
            columns = {r[1] for r in conn.execute("PRAGMA table_info(prompts)")}
            missing = [c for c in REQUIRED_PROMPT_COLUMNS if c not in columns]
            if missing:
                return (
                    False,
                    "prompts table is missing required columns: " + ", ".join(missing),
                )
            forbidden = conn.execute(
                "SELECT type FROM sqlite_master WHERE type IN ('trigger', 'view') "
                "LIMIT 1"
            ).fetchone()
            if forbidden:
                return False, f"Database contains an unsupported {forbidden[0]}"
            pair_error = PromptModel._pair_schema_error(conn)
            if pair_error:
                return False, pair_error
            history_error = history_schema_error(conn)
            if history_error:
                return False, history_error
            library_error = library_schema_error(
                conn, allow_missing=not require_library_state
            )
            if library_error:
                return False, library_error
            favorites_error = image_favorites_schema_error(
                conn, allow_missing=not require_library_state
            )
            if favorites_error:
                return False, favorites_error
            return True, "ok"
        except sqlite3.Error as e:
            return False, f"Invalid SQLite database: {e}"
        finally:
            conn.close()

    def _replace_contents_from(self, src_path: str) -> None:
        """Copy every page of *src_path* into the live database.

        Goes through SQLite's online backup API into this thread's normal
        connection, so SQLite takes the locks itself and the other
        PromptModel instances that share the file (nodes, image monitor,
        queue hook, API) simply see the new pages on their next statement.
        Nothing is swapped underneath open handles and no -wal/-shm file has
        to be deleted, which also keeps Windows happy. If SQLite refuses
        replacement (for example, incompatible page sizes in WAL mode),
        propagate the error rather than copy files under other open owners.
        """
        source = sqlite3.connect(
            Path(src_path).resolve().as_uri() + "?mode=ro", uri=True
        )
        try:
            source.backup(self.get_connection())
        finally:
            source.close()

    def restore_from_file(self, src_path: str) -> str:
        """
        Replace the live database with the file at src_path.

        A disposable SQLite backup of the source is migrated and verified first.
        Only then is the current database backed up next to itself as
        ``<db_path>.backup_<YYYYmmdd_HHMMSS>`` (WAL content included), and the
        staged pages replace the live pages through SQLite's backup API.
        Migration failures never replace live content or modify the source.
        An online replacement failure leaves the live database intact and
        propagates; the completed safety backup remains available.

        Args:
            src_path: SQLite file to restore

        Returns:
            Path of the backup taken of the previous database, or "" when
            there was no database to back up.

        Raises:
            RuntimeError: If the previous database could not be backed up
            sqlite3.OperationalError: If SQLite refuses online replacement
        """
        ok, reason = self.verify_database_file(src_path)
        if not ok:
            raise ValueError(reason)
        with tempfile.TemporaryDirectory(prefix="prompt-manager-restore-") as directory:
            staged_path = str(Path(directory) / "staged.db")
            source = sqlite3.connect(
                Path(src_path).resolve().as_uri() + "?mode=ro", uri=True
            )
            try:
                with closing(sqlite3.connect(staged_path)) as destination:
                    source.backup(destination)
            finally:
                source.close()
            staged = None
            try:
                staged = PromptModel(staged_path)
                rotate_history_epoch(staged.get_connection())
                ok, reason = self.verify_database_file(
                    staged_path, require_library_state=True
                )
                if not ok:
                    raise ValueError(reason)
                staged.close_all()
                backup_path = ""
                if os.path.exists(self.db_path):
                    timestamp = datetime.datetime.now().strftime("%Y%m%d_%H%M%S")
                    backup_path = f"{self.db_path}.backup_{timestamp}"
                    if not self.backup_database(backup_path):
                        raise RuntimeError("Could not back up the current database")
                    self.logger.info(f"Current database backed up to: {backup_path}")
                try:
                    self._replace_contents_from(staged_path)
                except sqlite3.OperationalError as exc:
                    exc._prompt_manager_restore_backup_created = bool(backup_path)
                    raise
                with PromptModel._init_lock:
                    PromptModel._initialized_paths.add(self._schema_key())
                self.logger.info(f"Database restored from {src_path}")
                from .execution_history import notify_history_restore

                notify_history_restore(self.db_path)
                return backup_path
            finally:
                if staged is not None:
                    staged.close_all()
                with PromptModel._init_lock:
                    PromptModel._initialized_paths.discard(
                        os.path.normcase(os.path.realpath(staged_path))
                    )