package database

import (
	"database/sql"
	"log"
	"strings"

	_ "github.com/mattn/go-sqlite3"
)

type Migrator func(*sql.DB) (*sql.DB, error)

func MigrateUsers(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating users table")

	_, err := dbConn.Exec(`CREATE TABLE IF NOT EXISTS users (
		id TEXT PRIMARY KEY,
		username TEXT NOT NULL,
		primary_mac TEXT,
		created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
		last_seen TIMESTAMP DEFAULT CURRENT_TIMESTAMP
	);`)
	if err != nil {
		return dbConn, err
	}

	_, err = dbConn.Exec(`CREATE UNIQUE INDEX IF NOT EXISTS idx_users_username ON users (username);`)
	return dbConn, err
}

// MigrateUserPrimaryMac adds primary_mac to pre-existing users tables. It's
// idempotent: SQLite has no "ADD COLUMN IF NOT EXISTS", so the duplicate-column
// error (column already present, e.g. on a fresh DB) is swallowed.
func MigrateUserPrimaryMac(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating users.primary_mac column")

	_, err := dbConn.Exec(`ALTER TABLE users ADD COLUMN primary_mac TEXT;`)
	if err != nil && !strings.Contains(err.Error(), "duplicate column name") {
		return dbConn, err
	}
	return dbConn, nil
}

// MigrateDNSRecords holds the user-editable DNS records served for the LAN zone.
func MigrateDNSRecords(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating dns_records table")

	_, err := dbConn.Exec(`CREATE TABLE IF NOT EXISTS dns_records (
		id TEXT PRIMARY KEY,
		user_id TEXT NOT NULL,
		name TEXT NOT NULL,
		type TEXT NOT NULL,
		content TEXT NOT NULL,
		ttl INTEGER NOT NULL,
		created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
		FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE
	);`)
	if err != nil {
		return dbConn, err
	}

	_, err = dbConn.Exec(`CREATE UNIQUE INDEX IF NOT EXISTS idx_dns_records_name_content_type ON dns_records (name, type, content);`)
	if err != nil {
		return dbConn, err
	}

	_, err = dbConn.Exec(`CREATE INDEX IF NOT EXISTS idx_dns_records_name_type ON dns_records (name, type);`)
	return dbConn, err
}

// MigrateMacs maps hardware addresses to users. One user can own many MACs —
// that's how a privacy-rotated device "logs back in" to an existing account.
func MigrateMacs(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating macs table")

	_, err := dbConn.Exec(`CREATE TABLE IF NOT EXISTS macs (
		mac TEXT PRIMARY KEY,
		user_id TEXT NOT NULL,
		first_seen TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
		last_seen TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
		FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE
	);`)
	return dbConn, err
}

func MigrateSessions(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating sessions table")

	_, err := dbConn.Exec(`CREATE TABLE IF NOT EXISTS sessions (
		id TEXT PRIMARY KEY,
		user_id TEXT NOT NULL,
		created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
		expire_at TIMESTAMP NOT NULL,
		FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE
	);`)
	return dbConn, err
}

func MigrateChat(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating chat table")

	_, err := dbConn.Exec(`CREATE TABLE IF NOT EXISTS chat (
		id TEXT PRIMARY KEY,
		user_id TEXT NOT NULL,
		body TEXT NOT NULL,
		created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
		FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE
	);`)
	if err != nil {
		return dbConn, err
	}

	_, err = dbConn.Exec(`CREATE INDEX IF NOT EXISTS idx_chat_created_at ON chat (created_at);`)
	return dbConn, err
}

func MigrateConnections(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating connections table")

	_, err := dbConn.Exec(`CREATE TABLE IF NOT EXISTS connections (
		ip TEXT PRIMARY KEY,
		mac TEXT NOT NULL,
		updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
	);`)
	return dbConn, err
}

func MigrateMinecraft(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating minecraft_status table")

	_, err := dbConn.Exec(`CREATE TABLE IF NOT EXISTS minecraft_status (
		id INTEGER PRIMARY KEY CHECK (id = 1),
		status TEXT NOT NULL,
		updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
	);`)
	return dbConn, err
}

func MigrateCanvas(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating canvas tables")

	_, err := dbConn.Exec(`CREATE TABLE IF NOT EXISTS canvas_pixels (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		user_id TEXT,
		x INTEGER NOT NULL,
		y INTEGER NOT NULL,
		color INTEGER NOT NULL,
		created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
		FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE SET NULL
	);`)
	if err != nil {
		return dbConn, err
	}

	_, err = dbConn.Exec(`CREATE TABLE IF NOT EXISTS canvas_snapshots (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		data BLOB NOT NULL,
		through_id INTEGER NOT NULL,
		created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
	);`)
	return dbConn, err
}

func Migrate(dbConn *sql.DB) (*sql.DB, error) {
	log.Println("migrating database")

	migrations := []Migrator{
		MigrateUsers,
		MigrateUserPrimaryMac,
		MigrateMacs,
		MigrateSessions,
		MigrateChat,
		MigrateConnections,
		MigrateMinecraft,
		MigrateCanvas,
		MigrateDNSRecords,
	}

	for _, migration := range migrations {
		var err error
		if dbConn, err = migration(dbConn); err != nil {
			return dbConn, err
		}
	}

	return dbConn, nil
}