package db

import (
	"context"
	"io/fs"
	"sync"

	"github.com/gin-gonic/gin"
	"github.com/jackc/pgx/v4"
	"github.com/jackc/pgx/v4/pgxpool"
	"github.com/jackc/tern/migrate"
	"github.com/phuslu/log"
	"go.sebtobie.de/httpserver/funcs"
	"go.sebtobie.de/httpserver/middleware"
)

// ContextKey is the key that is used in a gin.Context to get the Middleware
const ContextKey string = "db"

// ConnGet is an function that returns an connection instance.
type ConnGet func(string) *pgxpool.Conn

var _ ConnGet = NewMiddleware().GetConn
var _ middleware.Middleware = &Middleware{}

// Middleware return a handler that sets the db into the context of every request.
// uri is an url in the form dbtype:connectargs
type Middleware struct {
	databases map[string]*pgxpool.Pool
	lock      sync.Mutex
}

//NewMiddleware return an initialized Middleware Object.
func NewMiddleware() *Middleware {
	return &Middleware{
		databases: make(map[string]*pgxpool.Pool),
	}
}

// AddDB adds an db connection to the middleware.
func (m *Middleware) AddDB(name, uri string) (err error) {
	m.lock.Lock()
	if m.databases == nil {
		m.databases = map[string]*pgxpool.Pool{}
	}
	m.lock.Unlock()
	var (
		db         *pgxpool.Pool
		connobject *pgxpool.Config
	)
	if err != nil {
		log.Error().Err(err).Msg("Could not open the database")
		return err
	}
	connobject, err = pgxpool.ParseConfig(uri)
	if err != nil {
		log.Error().Err(err).Msg("Could not open the database")
		return err
	}
	connobject.ConnConfig.Logger = funcs.PGXLogger{}
	db, err = pgxpool.ConnectConfig(context.TODO(), connobject)
	if err != nil {
		log.Error().Err(err).Msg("Could not open the database")
		return err
	}
	m.lock.Lock()
	defer m.lock.Unlock()
	if olddb, found := m.databases[name]; found {
		olddb.Close()
	}
	m.databases[name] = db
	return
}

func (m *Middleware) getconn(name string) *pgxpool.Conn {
	if db, found := m.databases[name]; found {
		conn, err := db.Acquire(context.TODO())
		if err != nil {
			log.Error().Err(err).Msgf("Could not get the connection from the pool %s", name)
			return nil
		}
		return conn
	}
	return nil
}

// GetConn returns a connection from the specified database or if not found one of the default database.
func (m *Middleware) GetConn(name string) *pgxpool.Conn {
	m.lock.Lock()
	defer m.lock.Unlock()
	if conn := m.getconn(name); conn != nil {
		return conn
	}
	conn := m.getconn("default")
	return conn
}

// Gin is the Entrypoint for Gin.
func (m *Middleware) Gin(c *gin.Context) {
	c.Set(ContextKey, m.GetConn)
}

// Teardown closes the DBConnection
func (m *Middleware) Teardown() {
	for name, pool := range m.databases {
		log.Info().Msgf("Starting to close databasepool %s", name)
		pool.Close()
		log.Info().Msgf("Closed Databasepool %s", name)
	}
}

func logmigrations(version int32, name string, dir string, sql string) {
	sql = ""
	log.Info().Int32("version", version).Str("name", name).Str("dir", dir).Msgf("Running Migration %s with version %d in %sward direction", name, version, dir)
}

// SetupMigrator sets up the migrator to migrate the database.
func SetupMigrator(prefix string, connection *pgx.Conn, migrations fs.FS) (mig *migrate.Migrator, err error) {
	mig, err = migrate.NewMigratorEx(
		context.TODO(),
		connection,
		"version",
		&migrate.MigratorOptions{
			DisableTx:  false,
			MigratorFS: &iofsMigratorFS{fsys: migrations},
		},
	)
	if err != nil {
		log.Error().Err(err).Msg("Error while creating the migrator")
		return
	}
	mig.OnStart = logmigrations
	mig.Data["prefix"] = prefix
	return
}