package models

import (
	"database/sql"
	"fmt"
	"strings"
	"time"

	_ "modernc.org/sqlite"
)

// License represents a license record in the database.
type License struct {
	ID            string
	Key           string
	CustomerName  string
	CustomerEmail string
	ProductName   string
	Type          string // expiry | usage
	ExpiresAt     *time.Time
	MaxUses       *int
	UsedCount     int
	MachineID     string
	Active        bool
	CreatedAt     time.Time
	SearchText    string // pre-built lowercase search string for the UI
}

// Activation records each machine that activated a license.
type Activation struct {
	ID          string
	LicenseID   string
	MachineID   string
	Hostname    string
	OS          string
	ActivatedAt time.Time
}

// DB wraps the SQLite connection with helper methods.
type DB struct {
	conn *sql.DB
}

// Open opens (or creates) the SQLite database at path.
func Open(path string) (*DB, error) {
	conn, err := sql.Open("sqlite", path+"?_journal=WAL&_timeout=5000")
	if err != nil {
		return nil, err
	}
	db := &DB{conn: conn}
	return db, db.migrate()
}

func (db *DB) migrate() error {
	_, err := db.conn.Exec(`
		CREATE TABLE IF NOT EXISTS licenses (
			id             TEXT PRIMARY KEY,
			key            TEXT UNIQUE NOT NULL,
			customer_name  TEXT NOT NULL,
			customer_email TEXT NOT NULL,
			product_name   TEXT NOT NULL,
			type           TEXT NOT NULL,
			expires_at     DATETIME,
			max_uses       INTEGER,
			used_count     INTEGER NOT NULL DEFAULT 0,
			machine_id     TEXT,
			active         INTEGER NOT NULL DEFAULT 1,
			created_at     DATETIME NOT NULL
		);
		CREATE TABLE IF NOT EXISTS activations (
			id           TEXT PRIMARY KEY,
			license_id   TEXT NOT NULL REFERENCES licenses(id),
			machine_id   TEXT NOT NULL,
			hostname     TEXT,
			os           TEXT,
			activated_at DATETIME NOT NULL
		);
		CREATE TABLE IF NOT EXISTS users (
			id            TEXT PRIMARY KEY,
			email         TEXT UNIQUE NOT NULL,
			password_hash TEXT NOT NULL,
			created_at    DATETIME NOT NULL
		);
	`)
	return err
}

// --- License CRUD ---

func (db *DB) CreateLicense(l *License) error {
	_, err := db.conn.Exec(`
		INSERT INTO licenses (id, key, customer_name, customer_email, product_name,
		                      type, expires_at, max_uses, machine_id, active, created_at)
		VALUES (?,?,?,?,?,?,?,?,?,?,?)`,
		l.ID, l.Key, l.CustomerName, l.CustomerEmail, l.ProductName,
		l.Type, l.ExpiresAt, l.MaxUses, l.MachineID, l.Active, l.CreatedAt,
	)
	return err
}

func (db *DB) ListLicenses() ([]License, error) {
	rows, err := db.conn.Query(`
		SELECT id, key, customer_name, customer_email, product_name,
		       type, expires_at, max_uses, used_count, machine_id, active, created_at
		FROM licenses ORDER BY created_at DESC`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var licenses []License
	for rows.Next() {
		var l License
		if err := rows.Scan(&l.ID, &l.Key, &l.CustomerName, &l.CustomerEmail,
			&l.ProductName, &l.Type, &l.ExpiresAt, &l.MaxUses,
			&l.UsedCount, &l.MachineID, &l.Active, &l.CreatedAt); err != nil {
			return nil, err
		}
		l.SearchText = strings.ToLower(fmt.Sprintf("%s %s %s %s %s",
			l.Key, l.CustomerName, l.CustomerEmail, l.ProductName, l.MachineID))
		licenses = append(licenses, l)
	}
	return licenses, nil
}

func (db *DB) GetLicenseByKey(key string) (*License, error) {
	var l License
	err := db.conn.QueryRow(`
		SELECT id, key, customer_name, customer_email, product_name,
		       type, expires_at, max_uses, used_count, machine_id, active, created_at
		FROM licenses WHERE key = ?`, key).
		Scan(&l.ID, &l.Key, &l.CustomerName, &l.CustomerEmail,
			&l.ProductName, &l.Type, &l.ExpiresAt, &l.MaxUses,
			&l.UsedCount, &l.MachineID, &l.Active, &l.CreatedAt)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	return &l, err
}

func (db *DB) RevokeLicense(id string) error {
	_, err := db.conn.Exec(`UPDATE licenses SET active = 0 WHERE id = ?`, id)
	return err
}

func (db *DB) ActivateLicense(id string) error {
	_, err := db.conn.Exec(`UPDATE licenses SET active = 1 WHERE id = ?`, id)
	return err
}

func (db *DB) IncrementUsage(id string) error {
	_, err := db.conn.Exec(`UPDATE licenses SET used_count = used_count + 1 WHERE id = ?`, id)
	return err
}

// --- Activations ---

func (db *DB) RecordActivation(a *Activation) error {
	_, err := db.conn.Exec(`
		INSERT OR REPLACE INTO activations (id, license_id, machine_id, hostname, os, activated_at)
		VALUES (?,?,?,?,?,?)`,
		a.ID, a.LicenseID, a.MachineID, a.Hostname, a.OS, a.ActivatedAt,
	)
	return err
}

func (db *DB) ListActivations(licenseID string) ([]Activation, error) {
	rows, err := db.conn.Query(`
		SELECT id, license_id, machine_id, hostname, os, activated_at
		FROM activations WHERE license_id = ? ORDER BY activated_at DESC`, licenseID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var acts []Activation
	for rows.Next() {
		var a Activation
		rows.Scan(&a.ID, &a.LicenseID, &a.MachineID, &a.Hostname, &a.OS, &a.ActivatedAt)
		acts = append(acts, a)
	}
	return acts, nil
}

// --- Users ---

func (db *DB) CreateUser(id, email, hash string) error {
	_, err := db.conn.Exec(`
		INSERT INTO users (id, email, password_hash, created_at) VALUES (?,?,?,?)`,
		id, email, hash, time.Now())
	return err
}

func (db *DB) GetUserByEmail(email string) (id, hash string, err error) {
	err = db.conn.QueryRow(
		`SELECT id, password_hash FROM users WHERE email = ?`, email).
		Scan(&id, &hash)
	return
}

func (db *DB) UserCount() int {
	var n int
	db.conn.QueryRow(`SELECT COUNT(*) FROM users`).Scan(&n)
	return n
}