// Package db is the SQLite data layer, mirroring email_server/models.py. It uses plain
// database/sql + hand-written SQL rather than an ORM — the schema is small and fixed,
// so an ORM would be an unrequested abstraction.
package db

import (
	"database/sql"
	"fmt"

	_ "modernc.org/sqlite"
)

// schema creates all esrv_* tables if missing. There is no migration framework here,
// matching the Python precedent (its own migrations/ directory is a single manual SQL
// patch file, never auto-applied) — CREATE TABLE IF NOT EXISTS covers the whole surface.
const schema = `
CREATE TABLE IF NOT EXISTS esrv_domains (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	domain_name TEXT NOT NULL UNIQUE,
	is_active INTEGER NOT NULL DEFAULT 1,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
	verification_token TEXT NOT NULL DEFAULT '',
	is_verified INTEGER NOT NULL DEFAULT 0,
	verified_at DATETIME
);

CREATE TABLE IF NOT EXISTS esrv_senders (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	email TEXT NOT NULL UNIQUE,
	password_hash TEXT NOT NULL,
	domain_id INTEGER NOT NULL REFERENCES esrv_domains(id),
	can_send_as_domain INTEGER NOT NULL DEFAULT 0,
	is_active INTEGER NOT NULL DEFAULT 1,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
	store_message_content INTEGER NOT NULL DEFAULT 0
);

CREATE TABLE IF NOT EXISTS esrv_whitelisted_ips (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	ip_address TEXT NOT NULL,
	domain_id INTEGER NOT NULL REFERENCES esrv_domains(id),
	is_active INTEGER NOT NULL DEFAULT 1,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
	store_message_content INTEGER NOT NULL DEFAULT 0
);

CREATE TABLE IF NOT EXISTS esrv_email_logs (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	message_id TEXT NOT NULL UNIQUE,
	timestamp DATETIME NOT NULL,
	peer_ip TEXT NOT NULL,
	mail_from TEXT NOT NULL,
	to_address TEXT NOT NULL DEFAULT '',
	cc_addresses TEXT DEFAULT '',
	bcc_addresses TEXT DEFAULT '',
	subject TEXT,
	email_headers TEXT NOT NULL,
	message_body TEXT,
	status TEXT NOT NULL,
	dkim_signed INTEGER NOT NULL DEFAULT 0,
	username TEXT,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS esrv_email_recipient_logs (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	email_log_id INTEGER NOT NULL REFERENCES esrv_email_logs(id),
	recipient TEXT NOT NULL,
	recipient_type TEXT NOT NULL,
	status TEXT NOT NULL,
	error_code TEXT,
	error_message TEXT,
	server_response TEXT
);

CREATE TABLE IF NOT EXISTS esrv_auth_logs (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	auth_type TEXT NOT NULL,
	identifier TEXT NOT NULL,
	ip_address TEXT,
	success INTEGER NOT NULL,
	message TEXT,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS esrv_dkim_keys (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	domain_id INTEGER NOT NULL REFERENCES esrv_domains(id),
	selector TEXT NOT NULL DEFAULT 'default',
	private_key TEXT NOT NULL,
	public_key TEXT NOT NULL,
	is_active INTEGER NOT NULL DEFAULT 1,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
	replaced_at DATETIME
);

CREATE TABLE IF NOT EXISTS esrv_custom_headers (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	domain_id INTEGER NOT NULL REFERENCES esrv_domains(id),
	header_name TEXT NOT NULL,
	header_value TEXT NOT NULL,
	is_active INTEGER NOT NULL DEFAULT 1,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS esrv_email_attachments (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	email_log_id INTEGER NOT NULL REFERENCES esrv_email_logs(id),
	filename TEXT NOT NULL,
	content_type TEXT,
	file_path TEXT NOT NULL,
	size INTEGER,
	uploaded_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS esrv_admin_users (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	username TEXT NOT NULL UNIQUE,
	password_hash TEXT NOT NULL,
	must_change_password INTEGER NOT NULL DEFAULT 0,
	totp_secret TEXT NOT NULL DEFAULT '',
	totp_enabled INTEGER NOT NULL DEFAULT 0,
	is_global_admin INTEGER NOT NULL DEFAULT 0,
	created_by INTEGER,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

-- Which domains a non-global admin is allowed to see/manage. Global admins have no
-- rows here at all — their access is implicit (AdminUser.IsGlobalAdmin).
CREATE TABLE IF NOT EXISTS esrv_admin_domain_access (
	admin_user_id INTEGER NOT NULL REFERENCES esrv_admin_users(id),
	domain_id INTEGER NOT NULL REFERENCES esrv_domains(id),
	PRIMARY KEY (admin_user_id, domain_id)
);

CREATE TABLE IF NOT EXISTS esrv_admin_sessions (
	token TEXT PRIMARY KEY,
	user_id INTEGER NOT NULL REFERENCES esrv_admin_users(id),
	mfa_verified INTEGER NOT NULL DEFAULT 0,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
	expires_at DATETIME NOT NULL
);

CREATE TABLE IF NOT EXISTS esrv_webauthn_credentials (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	user_id INTEGER NOT NULL REFERENCES esrv_admin_users(id),
	name TEXT NOT NULL DEFAULT '',
	credential_id TEXT NOT NULL UNIQUE,
	credential_data TEXT NOT NULL,
	created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);
`

// migrateAddedColumns best-effort ALTER TABLEs the columns added to esrv_domains
// after its first release, for dev DBs created before this feature existed.
// CREATE TABLE IF NOT EXISTS doesn't retrofit columns onto an existing table, and
// there's no migration framework here (see the schema comment above) — errors are
// ignored since SQLite has no "ADD COLUMN IF NOT EXISTS" and a duplicate-column
// error just means the column is already there.
func migrateAddedColumns(db *sql.DB) {
	stmts := []string{
		`ALTER TABLE esrv_domains ADD COLUMN verification_token TEXT NOT NULL DEFAULT ''`,
		`ALTER TABLE esrv_domains ADD COLUMN is_verified INTEGER NOT NULL DEFAULT 0`,
		`ALTER TABLE esrv_domains ADD COLUMN verified_at DATETIME`,
		`ALTER TABLE esrv_admin_users ADD COLUMN is_global_admin INTEGER NOT NULL DEFAULT 0`,
		`ALTER TABLE esrv_admin_users ADD COLUMN created_by INTEGER`,
	}
	for _, stmt := range stmts {
		db.Exec(stmt)
	}
}

// DB wraps *sql.DB with the query helpers below.
type DB struct {
	*sql.DB
}

// Open opens (creating if needed) the SQLite file at path and ensures the schema exists.
func Open(path string) (*DB, error) {
	sqlDB, err := sql.Open("sqlite", path)
	if err != nil {
		return nil, fmt.Errorf("open sqlite: %w", err)
	}
	if _, err := sqlDB.Exec(schema); err != nil {
		sqlDB.Close()
		return nil, fmt.Errorf("create tables: %w", err)
	}
	migrateAddedColumns(sqlDB)
	return &DB{sqlDB}, nil
}