// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package bundb

import (
	"context"
	"errors"
	"time"

	"github.com/superseriousbusiness/gotosocial/internal/config"
	"github.com/superseriousbusiness/gotosocial/internal/db"
	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
	"github.com/superseriousbusiness/gotosocial/internal/log"
	"github.com/superseriousbusiness/gotosocial/internal/state"
	"github.com/superseriousbusiness/gotosocial/internal/util"
	"github.com/uptrace/bun"
)

type ruleDB struct {
	db    *DB
	state *state.State
}

func (r *ruleDB) GetRuleByID(ctx context.Context, id string) (*gtsmodel.Rule, error) {
	var rule gtsmodel.Rule

	q := r.db.
		NewSelect().
		Model(&rule).
		Where("? = ?", bun.Ident("rule.id"), id)

	if err := q.Scan(ctx); err != nil {
		return nil, err
	}

	return &rule, nil
}

func (r *ruleDB) GetRulesByIDs(ctx context.Context, ids []string) ([]*gtsmodel.Rule, error) {
	rules := make([]*gtsmodel.Rule, 0, len(ids))

	for _, id := range ids {
		// Attempt to fetch status from DB.
		rule, err := r.GetRuleByID(ctx, id)
		if err != nil {
			log.Errorf(ctx, "error getting rule %q: %v", id, err)
			continue
		}

		// Append status to return slice.
		rules = append(rules, rule)
	}

	return rules, nil
}

func (r *ruleDB) GetActiveRules(ctx context.Context) ([]gtsmodel.Rule, error) {
	rules := make([]gtsmodel.Rule, 0)

	q := r.db.
		NewSelect().
		Model(&rules).
		// Ignore deleted (ie., inactive) rules.
		Where("? = ?", bun.Ident("rule.deleted"), false).
		Order("rule.order ASC")

	if err := q.Scan(ctx); err != nil {
		return nil, err
	}

	return rules, nil
}

func (r *ruleDB) PutRule(ctx context.Context, rule *gtsmodel.Rule) error {
	var lastRuleOrder uint

	// Select highest existing rule order.
	err := r.db.
		NewSelect().
		TableExpr("? AS ?", bun.Ident("rules"), bun.Ident("rule")).
		Column("rule.order").
		Order("rule.order DESC").
		Limit(1).
		Scan(ctx, &lastRuleOrder)

	switch {
	case errors.Is(err, db.ErrNoEntries):
		// No rules set yet, index from 0.
		rule.Order = util.Ptr(uint(0))

	case err != nil:
		// Real db error.
		return err

	default:
		// No error means previous rule(s)
		// existed. New rule order should
		// be 1 higher than previous rule.
		rule.Order = func() *uint {
			o := lastRuleOrder + 1
			return &o
		}()
	}

	if _, err := r.db.
		NewInsert().
		Model(rule).
		Exec(ctx); err != nil {
		return err
	}

	// invalidate cached local instance response, so it gets updated with the new rules
	r.state.Caches.GTS.Instance().Invalidate("Domain", config.GetHost())

	return nil
}

func (r *ruleDB) UpdateRule(ctx context.Context, rule *gtsmodel.Rule) (*gtsmodel.Rule, error) {
	// Update the rule's last-updated
	rule.UpdatedAt = time.Now()

	if _, err := r.db.
		NewUpdate().
		Model(rule).
		WherePK().
		Exec(ctx); err != nil {
		return nil, err
	}

	// invalidate cached local instance response, so it gets updated with the new rules
	r.state.Caches.GTS.Instance().Invalidate("Domain", config.GetHost())

	return rule, nil
}