import type Database from "better-sqlite3";

// Version 4 matches the schema already deployed on us3. Never reuse its number.
function ensureCustomNodeColumns(db: Database.Database) {
  const columns = new Set(
    (db.pragma("table_info(hy2_nodes)") as { name: string }[]).map(
      (column) => column.name,
    ),
  );
  if (!columns.has("node_type"))
    db.exec(
      "ALTER TABLE hy2_nodes ADD COLUMN node_type TEXT NOT NULL DEFAULT 'hy2'",
    );
  if (!columns.has("custom_config_yaml"))
    db.exec(
      "ALTER TABLE hy2_nodes ADD COLUMN custom_config_yaml TEXT NOT NULL DEFAULT ''",
    );
}

const MIGRATIONS: (string | ((db: Database.Database) => void))[] = [
  `
  CREATE TABLE IF NOT EXISTS admins (
    id INTEGER PRIMARY KEY CHECK (id = 1),
    username TEXT NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL
  );

  CREATE TABLE IF NOT EXISTS admin_sessions (
    id TEXT PRIMARY KEY,
    admin_id INTEGER NOT NULL,
    session_hash TEXT NOT NULL UNIQUE,
    expires_at TEXT NOT NULL,
    created_at TEXT NOT NULL,
    last_seen_at TEXT NOT NULL,
    FOREIGN KEY (admin_id) REFERENCES admins(id) ON DELETE CASCADE
  );

  CREATE TABLE IF NOT EXISTS hy2_users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    auth_id TEXT NOT NULL UNIQUE,
    username TEXT NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,
    enabled INTEGER NOT NULL DEFAULT 1,
    expires_at TEXT,
    traffic_limit_bytes INTEGER,
    used_tx_bytes INTEGER NOT NULL DEFAULT 0,
    used_rx_bytes INTEGER NOT NULL DEFAULT 0,
    notes TEXT NOT NULL DEFAULT '',
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL
  );

  CREATE TABLE IF NOT EXISTS hy2_nodes (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    slug TEXT NOT NULL UNIQUE,
    name TEXT NOT NULL,
    auth_token TEXT NOT NULL,
    traffic_stats_url TEXT NOT NULL,
    traffic_stats_secret TEXT NOT NULL,
    enabled INTEGER NOT NULL DEFAULT 1,
    poll_interval_seconds INTEGER NOT NULL DEFAULT 15,
    last_polled_at TEXT,
    last_sync_ok_at TEXT,
    last_error_at TEXT,
    last_error_message TEXT,
    last_online_users INTEGER NOT NULL DEFAULT 0,
    last_stream_count INTEGER NOT NULL DEFAULT 0,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL
  );

  CREATE TABLE IF NOT EXISTS traffic_ledgers (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    node_id INTEGER NOT NULL,
    user_id INTEGER,
    auth_id TEXT NOT NULL,
    tx_bytes INTEGER NOT NULL,
    rx_bytes INTEGER NOT NULL,
    window_started_at TEXT NOT NULL,
    window_ended_at TEXT NOT NULL,
    created_at TEXT NOT NULL,
    FOREIGN KEY (node_id) REFERENCES hy2_nodes(id) ON DELETE CASCADE,
    FOREIGN KEY (user_id) REFERENCES hy2_users(id) ON DELETE SET NULL
  );

  CREATE TABLE IF NOT EXISTS node_sync_records (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    node_id INTEGER NOT NULL,
    started_at TEXT NOT NULL,
    finished_at TEXT NOT NULL,
    ok INTEGER NOT NULL,
    traffic_entries INTEGER NOT NULL DEFAULT 0,
    online_users INTEGER NOT NULL DEFAULT 0,
    stream_count INTEGER NOT NULL DEFAULT 0,
    kicked_auth_ids TEXT NOT NULL DEFAULT '',
    error_message TEXT,
    created_at TEXT NOT NULL,
    FOREIGN KEY (node_id) REFERENCES hy2_nodes(id) ON DELETE CASCADE
  );

  CREATE TABLE IF NOT EXISTS auth_audits (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    node_id INTEGER,
    user_id INTEGER,
    auth_id TEXT,
    username TEXT,
    addr TEXT,
    requested_tx INTEGER,
    ok INTEGER NOT NULL,
    reason TEXT NOT NULL,
    created_at TEXT NOT NULL,
    FOREIGN KEY (node_id) REFERENCES hy2_nodes(id) ON DELETE SET NULL,
    FOREIGN KEY (user_id) REFERENCES hy2_users(id) ON DELETE SET NULL
  );

  CREATE TABLE IF NOT EXISTS node_user_presence (
    node_id INTEGER NOT NULL,
    user_id INTEGER,
    auth_id TEXT NOT NULL,
    connections INTEGER NOT NULL DEFAULT 0,
    updated_at TEXT NOT NULL,
    PRIMARY KEY (node_id, auth_id),
    FOREIGN KEY (node_id) REFERENCES hy2_nodes(id) ON DELETE CASCADE,
    FOREIGN KEY (user_id) REFERENCES hy2_users(id) ON DELETE SET NULL
  );

  CREATE INDEX IF NOT EXISTS idx_hy2_users_auth_id ON hy2_users(auth_id);
  CREATE INDEX IF NOT EXISTS idx_hy2_users_username ON hy2_users(username);
  CREATE INDEX IF NOT EXISTS idx_hy2_nodes_enabled ON hy2_nodes(enabled);
  CREATE INDEX IF NOT EXISTS idx_traffic_ledgers_auth_id ON traffic_ledgers(auth_id);
  CREATE INDEX IF NOT EXISTS idx_traffic_ledgers_created_at ON traffic_ledgers(created_at);
  CREATE INDEX IF NOT EXISTS idx_node_sync_records_node_id ON node_sync_records(node_id, created_at DESC);
  CREATE INDEX IF NOT EXISTS idx_auth_audits_created_at ON auth_audits(created_at DESC);
  `,
  `
  ALTER TABLE hy2_users ADD COLUMN is_admin INTEGER NOT NULL DEFAULT 0;
  ALTER TABLE hy2_users ADD COLUMN auth_secret_encrypted TEXT;
  ALTER TABLE hy2_users ADD COLUMN subscription_token TEXT;
  ALTER TABLE hy2_users ADD COLUMN subscription_label TEXT NOT NULL DEFAULT '';

  CREATE TABLE IF NOT EXISTS user_sessions (
    id TEXT PRIMARY KEY,
    user_id INTEGER NOT NULL,
    session_hash TEXT NOT NULL UNIQUE,
    expires_at TEXT NOT NULL,
    created_at TEXT NOT NULL,
    last_seen_at TEXT NOT NULL,
    FOREIGN KEY (user_id) REFERENCES hy2_users(id) ON DELETE CASCADE
  );

  CREATE TABLE IF NOT EXISTS app_settings (
    key TEXT PRIMARY KEY,
    value TEXT NOT NULL,
    updated_at TEXT NOT NULL
  );

  ALTER TABLE hy2_nodes ADD COLUMN server_host TEXT NOT NULL DEFAULT '';
  ALTER TABLE hy2_nodes ADD COLUMN server_port INTEGER NOT NULL DEFAULT 443;
  ALTER TABLE hy2_nodes ADD COLUMN client_name TEXT NOT NULL DEFAULT '';
  ALTER TABLE hy2_nodes ADD COLUMN bandwidth_up_mbps INTEGER NOT NULL DEFAULT 30;
  ALTER TABLE hy2_nodes ADD COLUMN bandwidth_down_mbps INTEGER NOT NULL DEFAULT 30;
  ALTER TABLE hy2_nodes ADD COLUMN skip_cert_verify INTEGER NOT NULL DEFAULT 0;
  ALTER TABLE hy2_nodes ADD COLUMN sni TEXT;
  ALTER TABLE hy2_nodes ADD COLUMN traffic_stats_listen TEXT NOT NULL DEFAULT ':9999';

  CREATE UNIQUE INDEX IF NOT EXISTS idx_hy2_users_subscription_token ON hy2_users(subscription_token);
  CREATE INDEX IF NOT EXISTS idx_user_sessions_user_id ON user_sessions(user_id);
  `,
  `
  ALTER TABLE hy2_nodes ADD COLUMN hy2_listen TEXT NOT NULL DEFAULT ':443';
  `,
  ensureCustomNodeColumns,
];

export function migrateDatabase(db: Database.Database) {
  // Read the version under the same write lock as the migration to avoid races.
  db.transaction(() => {
    const currentVersion = db.pragma("user_version", {
      simple: true,
    }) as number;
    if (currentVersion > MIGRATIONS.length)
      throw new Error("数据库版本高于当前程序，请使用匹配的程序版本。");
    for (let index = currentVersion; index < MIGRATIONS.length; index += 1) {
      const migration = MIGRATIONS[index];
      if (typeof migration === "string") db.exec(migration);
      else migration(db);
      db.pragma(`user_version = ${index + 1}`);
    }
    // Also repairs a partially applied v4 without rewriting any existing data.
    ensureCustomNodeColumns(db);
  }).immediate();
}