package lib

// ============================================================================
// Auth Database (auth.db) - OAuth tokens and sessions
// ============================================================================
// Separate from medical data (inou.db). Volatile/ephemeral data.
// Schema documented in docs/schema-auth.sql
// ============================================================================

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

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

var authDB *sql.DB

// AuthDBInit opens the auth database connection
func AuthDBInit(dbPath string) error {
	var err error
	authDB, err = sql.Open("sqlite3", dbPath)
	return err
}

// AuthDBClose closes the auth database connection
func AuthDBClose() {
	if authDB != nil {
		authDB.Close()
	}
}

// authSave inserts or updates a record in auth.db (simplified, no encryption)
func authSave(table string, v interface{}) error {
	val := reflect.ValueOf(v)
	if val.Kind() == reflect.Ptr {
		val = val.Elem()
	}
	typ := val.Type()

	var cols []string
	var placeholders []string
	var vals []interface{}

	for i := 0; i < typ.NumField(); i++ {
		field := typ.Field(i)
		tag := field.Tag.Get("db")
		if tag == "" || tag == "-" {
			continue
		}
		parts := strings.Split(tag, ",")
		colName := parts[0]
		cols = append(cols, colName)
		placeholders = append(placeholders, "?")
		vals = append(vals, val.Field(i).Interface())
	}

	query := fmt.Sprintf(
		"INSERT OR REPLACE INTO %s (%s) VALUES (%s)",
		table,
		strings.Join(cols, ", "),
		strings.Join(placeholders, ", "),
	)

	_, err := authDB.Exec(query, vals...)
	return err
}

// authLoad retrieves a single record by primary key from auth.db
func authLoad(table string, pk interface{}, dest interface{}) error {
	val := reflect.ValueOf(dest)
	if val.Kind() != reflect.Ptr {
		return fmt.Errorf("dest must be a pointer")
	}
	val = val.Elem()
	typ := val.Type()

	var pkCol string
	var cols []string
	for i := 0; i < typ.NumField(); i++ {
		field := typ.Field(i)
		tag := field.Tag.Get("db")
		if tag == "" || tag == "-" {
			continue
		}
		parts := strings.Split(tag, ",")
		colName := parts[0]
		isPK := len(parts) > 1 && parts[1] == "pk"
		if isPK {
			pkCol = colName
		}
		cols = append(cols, colName)
	}

	query := fmt.Sprintf("SELECT %s FROM %s WHERE %s = ?", strings.Join(cols, ", "), table, pkCol)
	row := authDB.QueryRow(query, pk)

	// Build scan destinations
	ptrs := make([]interface{}, len(cols))
	colIdx := 0
	for i := 0; i < typ.NumField(); i++ {
		field := typ.Field(i)
		tag := field.Tag.Get("db")
		if tag == "" || tag == "-" {
			continue
		}
		ptrs[colIdx] = val.Field(i).Addr().Interface()
		colIdx++
	}

	return row.Scan(ptrs...)
}

// authQuery executes a SELECT and scans into a slice (for auth.db)
func authQuery(query string, args []interface{}, dest interface{}) error {
	rows, err := authDB.Query(query, args...)
	if err != nil {
		return err
	}
	defer rows.Close()

	sliceVal := reflect.ValueOf(dest)
	if sliceVal.Kind() != reflect.Ptr || sliceVal.Elem().Kind() != reflect.Slice {
		return fmt.Errorf("dest must be pointer to slice")
	}
	sliceVal = sliceVal.Elem()
	elemType := sliceVal.Type().Elem()
	isPtr := elemType.Kind() == reflect.Ptr
	if isPtr {
		elemType = elemType.Elem()
	}

	cols, _ := rows.Columns()

	for rows.Next() {
		elem := reflect.New(elemType).Elem()
		ptrs := make([]interface{}, len(cols))

		for i, col := range cols {
			for j := 0; j < elemType.NumField(); j++ {
				field := elemType.Field(j)
				tag := field.Tag.Get("db")
				if tag == "" {
					continue
				}
				parts := strings.Split(tag, ",")
				if parts[0] == col {
					ptrs[i] = elem.Field(j).Addr().Interface()
					break
				}
			}
			if ptrs[i] == nil {
				var dummy interface{}
				ptrs[i] = &dummy
			}
		}

		if err := rows.Scan(ptrs...); err != nil {
			return err
		}

		if isPtr {
			sliceVal.Set(reflect.Append(sliceVal, elem.Addr()))
		} else {
			sliceVal.Set(reflect.Append(sliceVal, elem))
		}
	}

	return rows.Err()
}

// authDelete removes a record by primary key from auth.db
func authDelete(table, pkCol string, pkVal interface{}) error {
	query := fmt.Sprintf("DELETE FROM %s WHERE %s = ?", table, pkCol)
	_, err := authDB.Exec(query, pkVal)
	return err
}