// The MIT License
//
// Copyright (c) 2021 Datadog, Inc.
//
// Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package sqlite

import (
	"fmt"
	"net/url"
	"strings"

	"github.com/iancoleman/strcase"
	"github.com/jmoiron/sqlx"

	"go.temporal.io/server/common/config"
	"go.temporal.io/server/common/persistence/sql"
	"go.temporal.io/server/common/persistence/sql/sqlplugin"
	"go.temporal.io/server/common/resolver"
)

const (
	// PluginName is the name of the plugin
	PluginName = "sqlite"
)

type plugin struct{}

var _ sqlplugin.Plugin = (*plugin)(nil)

func init() {
	sql.RegisterPlugin(PluginName, &plugin{})
}

// CreateDB initialize the db object
func (p *plugin) CreateDB(
	dbKind sqlplugin.DbKind,
	cfg *config.SQL,
	r resolver.ServiceResolver,
) (sqlplugin.DB, error) {
	conn, err := p.createDBConnection(cfg, r)
	if err != nil {
		return nil, err
	}
	db := newDB(dbKind, cfg.DatabaseName, conn, nil)
	return db, nil
}

// CreateAdminDB initialize the db object
func (p *plugin) CreateAdminDB(
	dbKind sqlplugin.DbKind,
	cfg *config.SQL,
	r resolver.ServiceResolver,
) (sqlplugin.AdminDB, error) {
	conn, err := p.createDBConnection(cfg, r)
	if err != nil {
		return nil, err
	}
	db := newDB(dbKind, cfg.DatabaseName, conn, nil)
	return db, nil
}

// createDBConnection creates a returns a reference to a logical connection to the
// underlying SQL database. The returned object is to tied to a single
// SQL database and the object can be used to perform CRUD operations on
// the tables in the database
func (p *plugin) createDBConnection(
	cfg *config.SQL,
	_ resolver.ServiceResolver,
) (*sqlx.DB, error) {
	dsn, err := buildDSN(cfg)
	if err != nil {
		return nil, fmt.Errorf("error building DSN: %w", err)
	}
	db, err := sqlx.Connect(goSqlDriverName, dsn)
	if err != nil {
		return nil, err
	}

	// The following options are set based on advice from https://github.com/mattn/go-sqlite3#faq
	//
	// Dealing with the error `database is locked`
	// > ... set the database connections of the SQL package to 1.
	db.SetMaxOpenConns(1)
	// Settings for in-memory database (should be fine for file mode as well)
	// > Note that if the last database connection in the pool closes, the in-memory database is deleted.
	// > Make sure the max idle connection limit is > 0, and the connection lifetime is infinite.
	db.SetMaxIdleConns(1)
	db.SetConnMaxIdleTime(0)

	// Maps struct names in CamelCase to snake without need for db struct tags.
	db.MapperFunc(strcase.ToSnake)

	return db, nil
}

func buildDSN(cfg *config.SQL) (string, error) {
	if cfg.ConnectAttributes == nil {
		cfg.ConnectAttributes = make(map[string]string)
	}
	vals, err := buildDSNAttr(cfg)
	if err != nil {
		return "", err
	}
	dsn := fmt.Sprintf(
		"file:%s?%v",
		cfg.DatabaseName,
		vals.Encode(),
	)
	return dsn, nil
}

func buildDSNAttr(cfg *config.SQL) (url.Values, error) {
	parameters := url.Values{}
	for k, v := range cfg.ConnectAttributes {
		key := strings.TrimSpace(k)
		value := strings.TrimSpace(v)
		if parameters.Get(key) != "" {
			return nil, fmt.Errorf("duplicate connection attr: %v:%v, %v:%v",
				key,
				parameters.Get(key),
				key, value,
			)
		}
		parameters.Set(key, value)
	}
	return parameters, nil
}