import type Database from 'better-sqlite3';

const initialized = new WeakSet<Database.Database>();
export function ensureHostSchema(handle: Database.Database): void {
    if (initialized.has(handle)) return;
    handle.exec(`
        CREATE TABLE IF NOT EXISTS ec_hosts (
            id TEXT PRIMARY KEY, name TEXT NOT NULL, hostname TEXT NOT NULL DEFAULT '',
            mode TEXT NOT NULL DEFAULT 'active' CHECK (mode IN ('active','draining','disabled')),
            port_min INTEGER NOT NULL DEFAULT 28960, port_max INTEGER NOT NULL DEFAULT 28980,
            bind_address TEXT NOT NULL DEFAULT '0.0.0.0', public_address TEXT NOT NULL DEFAULT '',
            minimum_free_bytes INTEGER NOT NULL DEFAULT 1073741824,
            created_at TEXT NOT NULL, enrolled_at TEXT, last_heartbeat TEXT, inventory TEXT NOT NULL DEFAULT '{}', deleted_at TEXT
        );
        CREATE TABLE IF NOT EXISTS ec_host_enrollments (
            id TEXT PRIMARY KEY, host_id TEXT NOT NULL REFERENCES ec_hosts(id), token_hash TEXT NOT NULL UNIQUE,
            created_at TEXT NOT NULL, expires_at TEXT NOT NULL, consumed_at TEXT
        );
        CREATE TABLE IF NOT EXISTS ec_host_credentials (
            id TEXT PRIMARY KEY, host_id TEXT NOT NULL REFERENCES ec_hosts(id), token_hash TEXT NOT NULL UNIQUE,
            created_at TEXT NOT NULL, revoked_at TEXT, last_used_at TEXT
        );
        CREATE TABLE IF NOT EXISTS ec_host_operations (
            id TEXT PRIMARY KEY, host_id TEXT NOT NULL REFERENCES ec_hosts(id), kind TEXT NOT NULL,
            instance_id TEXT, generation INTEGER, idempotency_key TEXT,
            payload TEXT NOT NULL, state TEXT NOT NULL DEFAULT 'pending'
                CHECK (state IN ('pending','accepted','running','completed','failed','unknown')),
            result TEXT, error TEXT, created_at TEXT NOT NULL, updated_at TEXT NOT NULL, last_delivered_at TEXT,
            UNIQUE(host_id, idempotency_key)
        );
        CREATE INDEX IF NOT EXISTS ec_host_operations_queue ON ec_host_operations(host_id, state, created_at);
        -- Polling checks cancellations and preparation by kind across retained
        -- history. The queue index cannot narrow those lookups beyond host_id,
        -- causing a history scan for every queued command on Node's main thread.
        CREATE INDEX IF NOT EXISTS ec_host_operations_kind ON ec_host_operations(host_id, kind, created_at);
        CREATE TABLE IF NOT EXISTS ec_host_operation_events (
            id INTEGER PRIMARY KEY AUTOINCREMENT, operation_id TEXT NOT NULL REFERENCES ec_host_operations(id),
            state TEXT NOT NULL, created_at TEXT NOT NULL, error TEXT
        );
        CREATE TABLE IF NOT EXISTS ec_host_ports (
            host_id TEXT NOT NULL REFERENCES ec_hosts(id), instance_id TEXT NOT NULL,
            bind_address TEXT NOT NULL, protocol TEXT NOT NULL CHECK (protocol IN ('udp','tcp')),
            port INTEGER NOT NULL CHECK (port BETWEEN 1 AND 65535), created_at TEXT NOT NULL,
            PRIMARY KEY(host_id,bind_address,protocol,port)
        );
        CREATE INDEX IF NOT EXISTS ec_host_ports_instance ON ec_host_ports(instance_id);
        CREATE TABLE IF NOT EXISTS ec_host_resource_samples (
            host_id TEXT NOT NULL REFERENCES ec_hosts(id), sampled_at TEXT NOT NULL,
            cpu_count REAL, cpu_usage_percent REAL, memory_total REAL, memory_available REAL,
            PRIMARY KEY(host_id, sampled_at)
        );
        CREATE TABLE IF NOT EXISTS ec_instance_resource_samples (
            host_id TEXT NOT NULL, instance_id TEXT NOT NULL, generation INTEGER NOT NULL,
            phase TEXT NOT NULL CHECK(phase IN ('startup','running')), bucket TEXT NOT NULL,
            cpu_cores REAL NOT NULL, memory_bytes REAL NOT NULL,
            PRIMARY KEY(host_id,instance_id,generation,phase,bucket)
        );
        CREATE INDEX IF NOT EXISTS ec_instance_resources_host ON ec_instance_resource_samples(host_id,phase,bucket DESC);
        CREATE INDEX IF NOT EXISTS ec_instance_resources_fleet ON ec_instance_resource_samples(phase,bucket DESC);
        CREATE INDEX IF NOT EXISTS ec_instance_resources_retention ON ec_instance_resource_samples(bucket);
        CREATE TABLE IF NOT EXISTS ec_resource_allowances (
            scope TEXT NOT NULL, phase TEXT NOT NULL, cpu_cores REAL NOT NULL, memory_bytes REAL NOT NULL,
            samples INTEGER NOT NULL, window_start TEXT NOT NULL, observed_at TEXT NOT NULL, computed_at TEXT NOT NULL,
            usage_margin REAL NOT NULL DEFAULT 1,
            PRIMARY KEY(scope,phase)
        );
        CREATE TABLE IF NOT EXISTS ec_host_decommissions (
            host_id TEXT PRIMARY KEY REFERENCES ec_hosts(id),
            operation_id TEXT NOT NULL UNIQUE REFERENCES ec_host_operations(id),
            token_hash TEXT NOT NULL, stage TEXT NOT NULL DEFAULT 'queued'
                CHECK(stage IN ('queued','running','cleaned','failed','completed')),
            requested_at TEXT NOT NULL, updated_at TEXT NOT NULL, cleaned_at TEXT, error TEXT
        );
    `);
    const columns = handle.prepare('PRAGMA table_info(ec_host_operations)').all() as { name: string }[];
    if (!columns.some(column => column.name === 'last_delivered_at')) handle.exec('ALTER TABLE ec_host_operations ADD COLUMN last_delivered_at TEXT');
    const hostColumns = handle.prepare('PRAGMA table_info(ec_hosts)').all() as { name: string }[];
    if (!hostColumns.some(column => column.name === 'deleted_at')) handle.exec('ALTER TABLE ec_hosts ADD COLUMN deleted_at TEXT');
    const allowanceColumns = handle.prepare('PRAGMA table_info(ec_resource_allowances)').all() as { name: string }[];
    if (!allowanceColumns.some(column => column.name === 'usage_margin')) {
        // Existing caches include 25% padding. Preserve learned evidence while
        // removing that padding exactly once, including dormant startup models.
        handle.transaction(() => {
            handle.exec('ALTER TABLE ec_resource_allowances ADD COLUMN usage_margin REAL NOT NULL DEFAULT 1');
            handle.exec('UPDATE ec_resource_allowances SET cpu_cores=cpu_cores/1.25, memory_bytes=CAST(memory_bytes/1.25 AS INTEGER)');
        })();
    }
    initialized.add(handle);
}