from __future__ import annotations

import sqlite3
from pathlib import Path

import click
from flask import Flask, current_app, g
from flask.cli import with_appcontext
from werkzeug.security import generate_password_hash

from .constants import DAYPARTS, DEFAULT_CATEGORIES, DEFAULT_CATEGORY_BUILDERS

CURRENT_SCHEMA_VERSION = "1.0.1"


def get_db() -> sqlite3.Connection:
    if "db" not in g:
        g.db = sqlite3.connect(
            current_app.config["DATABASE_PATH"],
            detect_types=sqlite3.PARSE_DECLTYPES,
            timeout=30,
        )
        g.db.row_factory = sqlite3.Row
        g.db.execute("PRAGMA foreign_keys = ON")
        g.db.execute("PRAGMA busy_timeout = 30000")
    return g.db


def close_db(_error=None) -> None:
    database = g.pop("db", None)
    if database is not None:
        database.close()


def table_columns(database: sqlite3.Connection, table_name: str) -> set[str]:
    rows = database.execute(f"PRAGMA table_info({table_name})").fetchall()
    return {row["name"] for row in rows}


def table_exists(database: sqlite3.Connection, table_name: str) -> bool:
    row = database.execute(
        "SELECT name FROM sqlite_master WHERE type = 'table' AND name = ?",
        (table_name,),
    ).fetchone()
    return row is not None


def add_column_if_missing(database: sqlite3.Connection, table_name: str, definition: str) -> None:
    column_name = definition.split()[0]
    if column_name not in table_columns(database, table_name):
        database.execute(f"ALTER TABLE {table_name} ADD COLUMN {definition}")


def ensure_meta_table(database: sqlite3.Connection) -> None:
    database.execute(
        """
        CREATE TABLE IF NOT EXISTS app_meta (
            key TEXT PRIMARY KEY,
            value TEXT,
            updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
        )
        """
    )


def get_meta(database: sqlite3.Connection, key: str) -> str | None:
    row = database.execute("SELECT value FROM app_meta WHERE key = ?", (key,)).fetchone()
    return row["value"] if row else None


def set_meta(database: sqlite3.Connection, key: str, value: str) -> None:
    database.execute(
        """
        INSERT INTO app_meta (key, value, updated_at)
        VALUES (?, ?, CURRENT_TIMESTAMP)
        ON CONFLICT(key) DO UPDATE SET value = excluded.value, updated_at = CURRENT_TIMESTAMP
        """,
        (key, value),
    )


def bootstrap_legacy_schema(database: sqlite3.Connection) -> None:
    ensure_meta_table(database)
    database.execute(
        """
        CREATE TABLE IF NOT EXISTS households (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL,
            shopping_weekday INTEGER NOT NULL DEFAULT 5,
            shopping_prep_days INTEGER NOT NULL DEFAULT 1,
            shopping_reminder_time TEXT NOT NULL DEFAULT '18:00',
            created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
        )
        """
    )

    database.execute(
        """
        CREATE TABLE IF NOT EXISTS household_categories (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            household_id INTEGER NOT NULL,
            name TEXT NOT NULL,
            builder_key TEXT NOT NULL DEFAULT 'neutral',
            sort_order INTEGER NOT NULL DEFAULT 100,
            is_active INTEGER NOT NULL DEFAULT 1,
            created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
            UNIQUE (household_id, name)
        )
        """
    )

    if table_exists(database, "households"):
        add_column_if_missing(database, "households", "shopping_weekday INTEGER NOT NULL DEFAULT 5")
        add_column_if_missing(database, "households", "shopping_prep_days INTEGER NOT NULL DEFAULT 1")
        add_column_if_missing(database, "households", "shopping_reminder_time TEXT NOT NULL DEFAULT '18:00'")

    if table_exists(database, "household_categories"):
        add_column_if_missing(database, "household_categories", "builder_key TEXT NOT NULL DEFAULT 'neutral'")

    if table_exists(database, "users"):
        add_column_if_missing(database, "users", "household_id INTEGER")
        add_column_if_missing(database, "users", "email TEXT")
        add_column_if_missing(database, "users", "role TEXT NOT NULL DEFAULT 'member'")
        add_column_if_missing(database, "users", "is_active INTEGER NOT NULL DEFAULT 1")
        add_column_if_missing(database, "users", "updated_at TEXT")

    if table_exists(database, "items"):
        add_column_if_missing(database, "items", "household_id INTEGER")
        add_column_if_missing(database, "items", "owner_user_id INTEGER")
        add_column_if_missing(database, "items", "target_user_id INTEGER")
        add_column_if_missing(database, "items", "visibility TEXT NOT NULL DEFAULT 'shared'")
        add_column_if_missing(database, "items", "energy_density TEXT NOT NULL DEFAULT 'neutral'")

    if table_exists(database, "shopping_entries"):
        add_column_if_missing(database, "shopping_entries", "household_id INTEGER")
        add_column_if_missing(database, "shopping_entries", "owner_user_id INTEGER")
        add_column_if_missing(database, "shopping_entries", "visibility TEXT NOT NULL DEFAULT 'shared'")
        add_column_if_missing(database, "shopping_entries", "needed_for_date TEXT")
        add_column_if_missing(database, "shopping_entries", "needed_for_daypart_id INTEGER")

    if table_exists(database, "shopping_needs"):
        add_column_if_missing(database, "shopping_needs", "source_item_id INTEGER")
        add_column_if_missing(database, "shopping_needs", "activation_date TEXT")
        add_column_if_missing(database, "shopping_needs", "is_activated INTEGER NOT NULL DEFAULT 0")
        add_column_if_missing(database, "shopping_needs", "activated_at TEXT")

    database.execute(
        """
        CREATE TABLE IF NOT EXISTS user_settings (
            user_id INTEGER PRIMARY KEY,
            reminders_enabled INTEGER NOT NULL DEFAULT 1,
            push_enabled INTEGER NOT NULL DEFAULT 0,
            notification_channel TEXT NOT NULL DEFAULT 'in_app',
            suggestion_style TEXT NOT NULL DEFAULT 'balanced',
            energy_preference TEXT NOT NULL DEFAULT 'neutral',
            remind_before_shopping INTEGER NOT NULL DEFAULT 1,
            remind_on_shopping_day INTEGER NOT NULL DEFAULT 1,
            show_missing_for_upcoming_week INTEGER NOT NULL DEFAULT 1,
            show_planned_not_shopped INTEGER NOT NULL DEFAULT 1,
            remind_tomorrow_if_sparse INTEGER NOT NULL DEFAULT 1,
            remind_week_if_sparse INTEGER NOT NULL DEFAULT 1,
            push_missing_breakfast INTEGER NOT NULL DEFAULT 0,
            push_missing_lunch INTEGER NOT NULL DEFAULT 0,
            push_missing_dinner INTEGER NOT NULL DEFAULT 0,
            suggest_home_for_today INTEGER NOT NULL DEFAULT 1,
            remind_small_snack INTEGER NOT NULL DEFAULT 0,
            remind_nuts INTEGER NOT NULL DEFAULT 0,
            show_meal_balancing INTEGER NOT NULL DEFAULT 1,
            suggest_templates INTEGER NOT NULL DEFAULT 1,
            suggest_patterns INTEGER NOT NULL DEFAULT 1,
            updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
            FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
        )
        """
    )

    database.execute(
        """
        CREATE TABLE IF NOT EXISTS push_subscriptions (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            user_id INTEGER NOT NULL,
            endpoint TEXT NOT NULL UNIQUE,
            p256dh TEXT NOT NULL,
            auth TEXT NOT NULL,
            user_agent TEXT,
            is_active INTEGER NOT NULL DEFAULT 1,
            created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
            updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
            last_test_at TEXT,
            FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
        )
        """
    )

    database.execute(
        """
        CREATE TABLE IF NOT EXISTS reminder_events (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            user_id INTEGER NOT NULL,
            event_key TEXT NOT NULL,
            created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
            UNIQUE (user_id, event_key),
            FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
        )
        """
    )

    database.execute(
        """
        CREATE TABLE IF NOT EXISTS hidden_generated_suggestions (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            user_id INTEGER NOT NULL,
            suggestion_key TEXT NOT NULL,
            created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
            UNIQUE (user_id, suggestion_key),
            FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
        )
        """
    )

    database.execute(
        """
        CREATE TABLE IF NOT EXISTS shopping_needs (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            household_id INTEGER NOT NULL,
            owner_user_id INTEGER,
            visibility TEXT NOT NULL DEFAULT 'shared',
            item_id INTEGER NOT NULL,
            source_item_id INTEGER,
            needed_for_date TEXT NOT NULL,
            needed_for_daypart_id INTEGER,
            activation_date TEXT NOT NULL,
            is_activated INTEGER NOT NULL DEFAULT 0,
            activated_at TEXT,
            created_by INTEGER,
            created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
            UNIQUE (item_id, source_item_id, needed_for_date, needed_for_daypart_id, visibility),
            FOREIGN KEY (household_id) REFERENCES households(id) ON DELETE CASCADE,
            FOREIGN KEY (owner_user_id) REFERENCES users(id) ON DELETE SET NULL,
            FOREIGN KEY (item_id) REFERENCES items(id) ON DELETE CASCADE,
            FOREIGN KEY (source_item_id) REFERENCES items(id) ON DELETE SET NULL,
            FOREIGN KEY (needed_for_daypart_id) REFERENCES dayparts(id) ON DELETE SET NULL,
            FOREIGN KEY (created_by) REFERENCES users(id) ON DELETE SET NULL
        )
        """
    )

    if table_exists(database, "plan_entries"):
        add_column_if_missing(database, "plan_entries", "household_id INTEGER")
        add_column_if_missing(database, "plan_entries", "owner_user_id INTEGER")
        add_column_if_missing(database, "plan_entries", "visibility TEXT NOT NULL DEFAULT 'shared'")

    if table_exists(database, "user_settings"):
        add_column_if_missing(database, "user_settings", "suggestion_style TEXT NOT NULL DEFAULT 'balanced'")
        add_column_if_missing(database, "user_settings", "energy_preference TEXT NOT NULL DEFAULT 'neutral'")
        add_column_if_missing(database, "user_settings", "push_missing_breakfast INTEGER NOT NULL DEFAULT 0")
        add_column_if_missing(database, "user_settings", "push_missing_lunch INTEGER NOT NULL DEFAULT 0")
        add_column_if_missing(database, "user_settings", "push_missing_dinner INTEGER NOT NULL DEFAULT 0")


def ensure_default_household(database: sqlite3.Connection) -> int:
    household = database.execute(
        "SELECT id FROM households ORDER BY id LIMIT 1"
    ).fetchone()
    if household:
        return int(household["id"])

    database.execute(
        "INSERT INTO households (name) VALUES (?)",
        ("Unser Haushalt",),
    )
    return int(database.execute("SELECT id FROM households ORDER BY id LIMIT 1").fetchone()["id"])


def household_ids(database: sqlite3.Connection) -> list[int]:
    return [int(row["id"]) for row in database.execute("SELECT id FROM households ORDER BY id").fetchall()]


def first_user_id(database: sqlite3.Connection) -> int | None:
    row = database.execute("SELECT id FROM users ORDER BY id LIMIT 1").fetchone()
    return int(row["id"]) if row else None


def sync_default_categories(database: sqlite3.Connection) -> None:
    for household_id in household_ids(database):
        legacy = database.execute(
            """
            SELECT id
            FROM household_categories
            WHERE household_id = ? AND name = 'Brot & Getreide'
            LIMIT 1
            """,
            (household_id,),
        ).fetchone()
        updated = database.execute(
            """
            SELECT id
            FROM household_categories
            WHERE household_id = ? AND name = 'Kohlenhydrate'
            LIMIT 1
            """,
            (household_id,),
        ).fetchone()
        if legacy and not updated:
            database.execute(
                """
                UPDATE household_categories
                SET name = 'Kohlenhydrate', builder_key = 'carb'
                WHERE id = ?
                """,
                (legacy["id"],),
            )
            database.execute(
                """
                UPDATE items
                SET category = 'Kohlenhydrate'
                WHERE household_id = ? AND category = 'Brot & Getreide'
                """,
                (household_id,),
            )
        for sort_order, name in enumerate(DEFAULT_CATEGORIES, start=10):
            database.execute(
                """
                INSERT OR IGNORE INTO household_categories (household_id, name, builder_key, sort_order, is_active)
                VALUES (?, ?, ?, ?, 1)
                """,
                (household_id, name, DEFAULT_CATEGORY_BUILDERS.get(name, "neutral"), sort_order),
            )
            database.execute(
                """
                UPDATE household_categories
                SET builder_key = COALESCE(NULLIF(builder_key, ''), ?)
                WHERE household_id = ? AND name = ?
                """,
                (DEFAULT_CATEGORY_BUILDERS.get(name, "neutral"), household_id, name),
            )


def ensure_schema_upgrades(database: sqlite3.Connection) -> None:
    ensure_meta_table(database)
    add_column_if_missing(database, "users", "household_id INTEGER")
    add_column_if_missing(database, "users", "email TEXT")
    add_column_if_missing(database, "users", "role TEXT NOT NULL DEFAULT 'member'")
    add_column_if_missing(database, "users", "is_active INTEGER NOT NULL DEFAULT 1")
    add_column_if_missing(database, "users", "updated_at TEXT")

    default_household_id = ensure_default_household(database)
    database.execute("UPDATE households SET shopping_weekday = 5 WHERE shopping_weekday IS NULL")
    database.execute("UPDATE households SET shopping_prep_days = 1 WHERE shopping_prep_days IS NULL")
    database.execute(
        "UPDATE households SET shopping_reminder_time = '18:00' WHERE shopping_reminder_time IS NULL OR shopping_reminder_time = ''"
    )
    database.execute(
        "UPDATE users SET household_id = ? WHERE household_id IS NULL",
        (default_household_id,),
    )
    database.execute("UPDATE users SET role = 'member' WHERE role IS NULL OR role = ''")
    database.execute("UPDATE users SET is_active = 1 WHERE is_active IS NULL")
    database.execute("UPDATE users SET email = NULL WHERE TRIM(COALESCE(email, '')) = ''")
    database.execute("UPDATE users SET updated_at = COALESCE(updated_at, created_at, CURRENT_TIMESTAMP)")

    admin_row = database.execute(
        "SELECT id FROM users WHERE role = 'admin' AND is_active = 1 ORDER BY id LIMIT 1"
    ).fetchone()
    if admin_row is None:
        first_id = first_user_id(database)
        if first_id is not None:
            database.execute("UPDATE users SET role = 'admin' WHERE id = ?", (first_id,))

    default_owner_id = first_user_id(database)
    for table_name in ("items", "shopping_entries", "plan_entries"):
        add_column_if_missing(database, table_name, "household_id INTEGER")
        add_column_if_missing(database, table_name, "owner_user_id INTEGER")
        add_column_if_missing(database, table_name, "visibility TEXT NOT NULL DEFAULT 'shared'")
    add_column_if_missing(database, "items", "target_user_id INTEGER")
    add_column_if_missing(database, "items", "energy_density TEXT NOT NULL DEFAULT 'neutral'")
    add_column_if_missing(database, "shopping_entries", "needed_for_date TEXT")
    add_column_if_missing(database, "shopping_entries", "needed_for_daypart_id INTEGER")
    add_column_if_missing(database, "user_settings", "suggestion_style TEXT NOT NULL DEFAULT 'balanced'")
    add_column_if_missing(database, "user_settings", "energy_preference TEXT NOT NULL DEFAULT 'neutral'")
    add_column_if_missing(database, "user_settings", "push_missing_breakfast INTEGER NOT NULL DEFAULT 0")
    add_column_if_missing(database, "user_settings", "push_missing_lunch INTEGER NOT NULL DEFAULT 0")
    add_column_if_missing(database, "user_settings", "push_missing_dinner INTEGER NOT NULL DEFAULT 0")

    if default_owner_id is not None:
        database.execute(
            """
            UPDATE items
            SET household_id = COALESCE(household_id, ?),
                owner_user_id = COALESCE(owner_user_id, created_by, ?),
                visibility = CASE WHEN visibility IS NULL OR visibility = '' THEN 'shared' ELSE visibility END
            WHERE household_id IS NULL OR owner_user_id IS NULL OR visibility IS NULL OR visibility = ''
            """,
            (default_household_id, default_owner_id),
        )
        database.execute(
            """
            UPDATE shopping_entries
            SET household_id = COALESCE(household_id, ?),
                owner_user_id = COALESCE(owner_user_id, added_by, ?),
                visibility = CASE WHEN visibility IS NULL OR visibility = '' THEN 'shared' ELSE visibility END
            WHERE household_id IS NULL OR owner_user_id IS NULL OR visibility IS NULL OR visibility = ''
            """,
            (default_household_id, default_owner_id),
        )
        database.execute(
            """
            UPDATE plan_entries
            SET household_id = COALESCE(household_id, ?),
                owner_user_id = COALESCE(owner_user_id, created_by, ?),
                visibility = CASE WHEN visibility IS NULL OR visibility = '' THEN 'shared' ELSE visibility END
            WHERE household_id IS NULL OR owner_user_id IS NULL OR visibility IS NULL OR visibility = ''
            """,
            (default_household_id, default_owner_id),
        )
    else:
        database.execute("UPDATE items SET visibility = 'shared' WHERE visibility IS NULL OR visibility = ''")
        database.execute("UPDATE shopping_entries SET visibility = 'shared' WHERE visibility IS NULL OR visibility = ''")
        database.execute("UPDATE plan_entries SET visibility = 'shared' WHERE visibility IS NULL OR visibility = ''")

    sync_default_categories(database)
    database.execute(
        """
        INSERT OR IGNORE INTO user_settings (user_id)
        SELECT id FROM users
        """
    )
    database.execute("UPDATE items SET energy_density = 'neutral' WHERE energy_density IS NULL OR energy_density = ''")
    database.execute("UPDATE user_settings SET suggestion_style = 'balanced' WHERE suggestion_style IS NULL OR suggestion_style = ''")
    database.execute("UPDATE user_settings SET energy_preference = 'neutral' WHERE energy_preference IS NULL OR energy_preference = ''")
    database.execute("UPDATE user_settings SET push_missing_breakfast = 0 WHERE push_missing_breakfast IS NULL")
    database.execute("UPDATE user_settings SET push_missing_lunch = 0 WHERE push_missing_lunch IS NULL")
    database.execute("UPDATE user_settings SET push_missing_dinner = 0 WHERE push_missing_dinner IS NULL")

    database.execute(
        """
        CREATE UNIQUE INDEX IF NOT EXISTS idx_users_email_unique
        ON users (email)
        WHERE email IS NOT NULL AND email != ''
        """
    )
    database.execute(
        """
        CREATE INDEX IF NOT EXISTS idx_items_household_visibility
        ON items (household_id, visibility, availability_state)
        """
    )
    database.execute(
        """
        CREATE INDEX IF NOT EXISTS idx_items_target_user
        ON items (target_user_id)
        """
    )
    database.execute(
        """
        CREATE INDEX IF NOT EXISTS idx_plan_entries_household_visibility
        ON plan_entries (household_id, visibility, plan_date)
        """
    )
    database.execute(
        """
        CREATE INDEX IF NOT EXISTS idx_shopping_entries_household_visibility
        ON shopping_entries (household_id, visibility, is_checked)
        """
    )
    database.execute(
        """
        CREATE INDEX IF NOT EXISTS idx_shopping_needs_household_activation
        ON shopping_needs (household_id, activation_date, is_activated)
        """
    )
    database.execute(
        """
        CREATE INDEX IF NOT EXISTS idx_hidden_generated_suggestions_user
        ON hidden_generated_suggestions (user_id)
        """
    )
    set_meta(database, "schema_version", CURRENT_SCHEMA_VERSION)


def apply_schema(database: sqlite3.Connection) -> None:
    bootstrap_legacy_schema(database)
    schema_path = Path(__file__).with_name("schema.sql")
    database.executescript(schema_path.read_text(encoding="utf-8"))
    ensure_schema_upgrades(database)
    sync_dayparts(database)


def init_db() -> None:
    database = get_db()
    apply_schema(database)
    database.commit()


def sync_dayparts(database: sqlite3.Connection) -> None:
    for entry in DAYPARTS:
        database.execute(
            """
            INSERT OR IGNORE INTO dayparts (slug, name, sort_order)
            VALUES (?, ?, ?)
            """,
            (entry["slug"], entry["name"], entry["sort_order"]),
        )
        database.execute(
            """
            UPDATE dayparts
            SET name = ?, sort_order = ?
            WHERE slug = ?
            """,
            (entry["name"], entry["sort_order"], entry["slug"]),
        )


def init_db_if_needed(app: Flask) -> None:
    with app.app_context():
        init_db()


def user_count() -> int:
    row = get_db().execute("SELECT COUNT(*) AS count FROM users").fetchone()
    return int(row["count"])


def active_admin_count(household_id: int) -> int:
    row = get_db().execute(
        """
        SELECT COUNT(*) AS count
        FROM users
        WHERE household_id = ? AND role = 'admin' AND is_active = 1
        """,
        (household_id,),
    ).fetchone()
    return int(row["count"])


@click.command("init-db")
@with_appcontext
def init_db_command() -> None:
    init_db()
    click.echo("Database initialized.")


@click.command("create-user")
@click.argument("username")
@click.argument("password")
@click.option("--display-name", default="", help="Friendly display name.")
@click.option("--email", default="", help="Optional email address.")
@click.option("--role", default="member", type=click.Choice(["admin", "member"]))
@with_appcontext
def create_user_command(username: str, password: str, display_name: str, email: str, role: str) -> None:
    database = get_db()
    household_id = ensure_default_household(database)
    database.execute(
        """
        INSERT INTO users (household_id, username, email, display_name, role, password_hash)
        VALUES (?, ?, ?, ?, ?, ?)
        """,
        (
            household_id,
            username.strip().lower(),
            email.strip().lower() or None,
            display_name.strip(),
            role,
            generate_password_hash(password),
        ),
    )
    database.commit()
    click.echo(f"User '{username}' created.")


def init_app(app: Flask) -> None:
    app.teardown_appcontext(close_db)
    app.cli.add_command(init_db_command)
    app.cli.add_command(create_user_command)