package db

import (
	"context"
	"database/sql"
	"net/http"

	"github.com/pkg/errors"
	"github.com/uptrace/bun"
)

type deleter[T any] struct {
	tx            bun.Tx
	q             *bun.DeleteQuery
	resourceID    any // Store ID before deletion for audit
	auditCallback AuditCallback
	auditRequest  *http.Request
}

type systemType interface {
	isSystem() bool
}

func DeleteItem[T any](tx bun.Tx) *deleter[T] {
	return &deleter[T]{
		tx: tx,
		q: tx.NewDelete().
			Model((*T)(nil)),
	}
}

func (d *deleter[T]) Where(query string, args ...any) *deleter[T] {
	d.q = d.q.Where(query, args...)
	// Try to capture resource ID from WHERE clause if it's a simple "id = ?" pattern
	if query == "id = ?" && len(args) > 0 {
		d.resourceID = args[0]
	}
	return d
}

// WithAudit enables audit logging for this delete operation
// The callback will be invoked after successful deletion with auto-generated audit info
// If the callback returns an error, the transaction will be rolled back
func (d *deleter[T]) WithAudit(r *http.Request, callback AuditCallback) *deleter[T] {
	d.auditRequest = r
	d.auditCallback = callback
	return d
}

func (d *deleter[T]) Delete(ctx context.Context) error {
	_, err := d.q.Exec(ctx)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil
		}
		return errors.Wrap(err, "bun.DeleteQuery.Exec")
	}

	// Handle audit logging if enabled
	if d.auditCallback != nil && d.auditRequest != nil {
		tableName := extractTableName[T]()
		resourceType := extractResourceType(tableName)
		action := buildAction(resourceType, "delete")

		info := &AuditInfo{
			Action:       action,
			ResourceType: resourceType,
			ResourceID:   d.resourceID,
			Details:      nil, // Delete doesn't need details
		}

		// Call audit callback - if it fails, return error to trigger rollback
		if err := d.auditCallback(ctx, d.tx, info, d.auditRequest); err != nil {
			return errors.Wrap(err, "audit.callback")
		}
	}

	return nil
}

func DeleteByID[T any](tx bun.Tx, id int) *deleter[T] {
	return DeleteItem[T](tx).Where("id = ?", id)
}

func DeleteWithProtection[T systemType](ctx context.Context, tx bun.Tx, id int) error {
	deleter := DeleteByID[T](tx, id)
	item, err := GetByID[T](tx, id).GetFirst(ctx)
	if err != nil {
		return errors.Wrap(err, "GetByID")
	}
	if item == nil {
		return errors.New("record not found")
	}
	if (*item).isSystem() {
		return errors.New("record is system protected")
	}
	return deleter.Delete(ctx)
}