package sqlite

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/glebarez/sqlite"
	"github.com/rose_cat707/luminary/internal/model"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

type Store struct {
	db *gorm.DB
}

func New(path string) (*Store, error) {
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		return nil, fmt.Errorf("create data dir: %w", err)
	}
	db, err := gorm.Open(sqlite.Open(path+"?_pragma=journal_mode(WAL)&_pragma=busy_timeout(5000)"), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Warn),
	})
	if err != nil {
		return nil, fmt.Errorf("open sqlite: %w", err)
	}
	sqlDB, err := db.DB()
	if err != nil {
		return nil, err
	}
	sqlDB.SetMaxOpenConns(1)
	if err := ensureIPRulesSchema(db); err != nil {
		return nil, fmt.Errorf("migrate ip_rules: %w", err)
	}
	if err := db.AutoMigrate(
		&model.Provider{},
		&model.ProviderKey{},
		&model.ModelEntry{},
		&model.IngressKey{},
		&model.AdminUser{},
		&model.AdminSession{},
		&model.UsageRecord{},
		&model.HealthCheckRecord{},
		&model.RoutingRule{},
		&model.SystemSettings{},
		&model.Prediction{},
		&model.StoredImage{},
	); err != nil {
		return nil, fmt.Errorf("migrate: %w", err)
	}
	return &Store{db: db}, nil
}

// ensureIPRulesSchema manages ip_rules without GORM AutoMigrate (avoids bad table rebuilds).
func ensureIPRulesSchema(db *gorm.DB) error {
	if !tableExists(db, "ip_rules") {
		return db.Exec(`
			CREATE TABLE ip_rules (
				id INTEGER PRIMARY KEY AUTOINCREMENT,
				cidr TEXT NOT NULL,
				type TEXT NOT NULL,
				scope TEXT NOT NULL DEFAULT 'proxy',
				enabled NUMERIC DEFAULT 1,
				created_at DATETIME
			);
		`).Error
	}
	if !tableHasColumn(db, "ip_rules", "c_id_r") {
		return nil
	}

	cidrExpr := "c_id_r"
	if tableHasColumn(db, "ip_rules", "cidr") {
		cidrExpr = "COALESCE(NULLIF(cidr, ''), c_id_r)"
	}

	return db.Exec(`
		CREATE TABLE ip_rules_mig (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			cidr TEXT NOT NULL,
			type TEXT NOT NULL,
			scope TEXT NOT NULL DEFAULT 'proxy',
			enabled NUMERIC DEFAULT 1,
			created_at DATETIME
		);
		INSERT INTO ip_rules_mig (id, cidr, type, scope, enabled, created_at)
			SELECT id, ` + cidrExpr + `, type, scope, enabled, created_at
			FROM ip_rules;
		DROP TABLE ip_rules;
		ALTER TABLE ip_rules_mig RENAME TO ip_rules;
	`).Error
}

func tableHasColumn(db *gorm.DB, table, column string) bool {
	var n int64
	db.Raw(`SELECT COUNT(*) FROM pragma_table_info(?) WHERE name = ?`, table, column).Scan(&n)
	return n > 0
}

func tableExists(db *gorm.DB, table string) bool {
	var n int64
	db.Raw(`SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name=?`, table).Scan(&n)
	return n > 0
}

func (s *Store) DB() *gorm.DB {
	return s.db
}