package postgres

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"net/url"

	"github.com/lib/pq"
	_ "github.com/lib/pq"
	"gitlab-odx.oracle.com/odx/functions/api/datastore/internal/datastoreutil"
	"gitlab-odx.oracle.com/odx/functions/api/models"
)

const routesTableCreate = `
CREATE TABLE IF NOT EXISTS routes (
	app_name character varying(256) NOT NULL,
	path text NOT NULL,
	image character varying(256) NOT NULL,
	format character varying(16) NOT NULL,
	memory integer NOT NULL,
	timeout integer NOT NULL,
	idle_timeout integer NOT NULL,
	type character varying(16) NOT NULL,
	headers text NOT NULL,
	config text NOT NULL,
	PRIMARY KEY (app_name, path)
);`

const appsTableCreate = `CREATE TABLE IF NOT EXISTS apps (
    name character varying(256) NOT NULL PRIMARY KEY,
	config text NOT NULL
);`

const extrasTableCreate = `CREATE TABLE IF NOT EXISTS extras (
    key character varying(256) NOT NULL PRIMARY KEY,
	value character varying(256) NOT NULL
);`

const routeSelector = `SELECT app_name, path, image, format, memory, type, timeout, idle_timeout, headers, config FROM routes`

const callsTableCreate = `CREATE TABLE IF NOT EXISTS calls (
	created_at character varying(256) NOT NULL,
	started_at character varying(256) NOT NULL,
	completed_at character varying(256) NOT NULL,
	status character varying(256) NOT NULL,
	id character varying(256) NOT NULL,
	app_name character varying(256) NOT NULL,
	path character varying(256) NOT NULL,
	PRIMARY KEY (id)
);`

const callSelector = `SELECT id, created_at, started_at, completed_at, status, app_name, path FROM calls`

type PostgresDatastore struct {
	db *sql.DB
}

func New(url *url.URL) (models.Datastore, error) {
	tables := []string{routesTableCreate, appsTableCreate, extrasTableCreate, callsTableCreate}
	sqlDatastore := &PostgresDatastore{}
	dialect := "postgres"

	db, err := datastoreutil.NewDatastore(url.String(), dialect, tables)
	if err != nil {
		return nil, err
	}

	sqlDatastore.db = db
	return datastoreutil.NewValidator(sqlDatastore), nil
}

func (ds *PostgresDatastore) InsertApp(ctx context.Context, app *models.App) (*models.App, error) {
	var cbyte []byte
	var err error

	if app.Config != nil {
		cbyte, err = json.Marshal(app.Config)
		if err != nil {
			return nil, err
		}
	}

	_, err = ds.db.Exec(`INSERT INTO apps (name, config) VALUES ($1, $2);`,
		app.Name,
		string(cbyte),
	)

	if err != nil {
		pqErr := err.(*pq.Error)
		if pqErr.Code == "23505" {
			return nil, models.ErrAppsAlreadyExists
		}
		return nil, err
	}

	return app, nil
}

func (ds *PostgresDatastore) UpdateApp(ctx context.Context, newapp *models.App) (*models.App, error) {
	app := &models.App{Name: newapp.Name}
	err := ds.Tx(func(tx *sql.Tx) error {
		row := ds.db.QueryRow("SELECT config FROM apps WHERE name=$1", app.Name)

		var config string
		if err := row.Scan(&config); err != nil {
			if err == sql.ErrNoRows {
				return models.ErrAppsNotFound
			}
			return err
		}

		if len(config) > 0 {
			err := json.Unmarshal([]byte(config), &app.Config)
			if err != nil {
				return err
			}
		}

		app.UpdateConfig(newapp.Config)

		cbyte, err := json.Marshal(app.Config)
		if err != nil {
			return err
		}

		res, err := ds.db.Exec(`UPDATE apps SET config = $2 WHERE name = $1;`, app.Name, string(cbyte))
		if err != nil {
			return err
		}

		if n, err := res.RowsAffected(); err != nil {
			return err
		} else if n == 0 {
			return models.ErrAppsNotFound
		}
		return nil
	})

	if err != nil {
		return nil, err
	}

	return app, nil
}

func (ds *PostgresDatastore) RemoveApp(ctx context.Context, appName string) error {
	_, err := ds.db.Exec(`DELETE FROM apps WHERE name = $1`, appName)

	return err
}

func (ds *PostgresDatastore) GetApp(ctx context.Context, name string) (*models.App, error) {
	queryStr := "SELECT name, config FROM apps WHERE name=$1"
	queryArgs := []interface{}{name}

	return datastoreutil.SQLGetApp(ds.db, queryStr, queryArgs...)
}

func (ds *PostgresDatastore) GetApps(ctx context.Context, filter *models.AppFilter) ([]*models.App, error) {
	whereStm := "WHERE name LIKE $1"
	selectStm := "SELECT DISTINCT * FROM apps %s"

	return datastoreutil.SQLGetApps(ds.db, filter, whereStm, selectStm)
}

func (ds *PostgresDatastore) InsertRoute(ctx context.Context, route *models.Route) (*models.Route, error) {
	hbyte, err := json.Marshal(route.Headers)
	if err != nil {
		return nil, err
	}

	cbyte, err := json.Marshal(route.Config)
	if err != nil {
		return nil, err
	}

	err = ds.Tx(func(tx *sql.Tx) error {
		r := tx.QueryRow(`SELECT 1 FROM apps WHERE name=$1`, route.AppName)
		if err := r.Scan(new(int)); err != nil {
			if err == sql.ErrNoRows {
				return models.ErrAppsNotFound
			}
			return err
		}

		same, err := tx.Query(`SELECT 1 FROM routes WHERE app_name=$1 AND path=$2`,
			route.AppName, route.Path)
		if err != nil {
			return err
		}
		defer same.Close()
		if same.Next() {
			return models.ErrRoutesAlreadyExists
		}

		_, err = tx.Exec(`
		INSERT INTO routes (
			app_name,
			path,
			image,
			format,
			memory,
			type,
			timeout,
			idle_timeout,
			headers,
			config
		)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10);`,
			route.AppName,
			route.Path,
			route.Image,
			route.Format,
			route.Memory,
			route.Type,
			route.Timeout,
			route.IdleTimeout,
			string(hbyte),
			string(cbyte),
		)
		return err
	})

	if err != nil {
		return nil, err
	}
	return route, nil
}

func (ds *PostgresDatastore) UpdateRoute(ctx context.Context, newroute *models.Route) (*models.Route, error) {
	var route models.Route
	err := ds.Tx(func(tx *sql.Tx) error {
		row := ds.db.QueryRow(fmt.Sprintf("%s WHERE app_name=$1 AND path=$2", routeSelector), newroute.AppName, newroute.Path)
		if err := datastoreutil.ScanRoute(row, &route); err == sql.ErrNoRows {
			return models.ErrRoutesNotFound
		} else if err != nil {
			return err
		}

		route.Update(newroute)

		hbyte, err := json.Marshal(route.Headers)
		if err != nil {
			return err
		}

		cbyte, err := json.Marshal(route.Config)
		if err != nil {
			return err
		}

		res, err := tx.Exec(`
		UPDATE routes SET
			image = $3,
			format = $4,
			memory = $5,
			type = $6,
			timeout = $7,
			idle_timeout = $8,
			headers = $9,
			config = $10
		WHERE app_name = $1 AND path = $2;`,
			route.AppName,
			route.Path,
			route.Image,
			route.Format,
			route.Memory,
			route.Type,
			route.Timeout,
			route.IdleTimeout,
			string(hbyte),
			string(cbyte),
		)

		if err != nil {
			return err
		}

		if n, err := res.RowsAffected(); err != nil {
			return err
		} else if n == 0 {
			return models.ErrRoutesNotFound
		}

		return nil
	})

	if err != nil {
		return nil, err
	}
	return &route, nil
}

func (ds *PostgresDatastore) RemoveRoute(ctx context.Context, appName, routePath string) error {
	deleteStm := `DELETE FROM routes WHERE path = $1 AND app_name = $2`
	return datastoreutil.SQLRemoveRoute(ds.db, appName, routePath, deleteStm)
}

func (ds *PostgresDatastore) GetRoute(ctx context.Context, appName, routePath string) (*models.Route, error) {
	rSelectCondition := "%s WHERE app_name=$1 AND path=$2"

	return datastoreutil.SQLGetRoute(ds.db, appName, routePath, rSelectCondition, routeSelector)
}

func (ds *PostgresDatastore) GetRoutes(ctx context.Context, filter *models.RouteFilter) ([]*models.Route, error) {
	whereStm := "WHERE %s $1"
	andStm := " AND %s $%d"

	return datastoreutil.SQLGetRoutes(ds.db, filter, routeSelector, whereStm, andStm)
}

func (ds *PostgresDatastore) GetRoutesByApp(ctx context.Context, appName string, filter *models.RouteFilter) ([]*models.Route, error) {
	defaultFilterQuery := "WHERE app_name = $1"
	whereStm := "WHERE %s $1"
	andStm := " AND %s $%d"

	return datastoreutil.SQLGetRoutesByApp(ds.db, appName, filter, routeSelector, defaultFilterQuery, whereStm, andStm)
}

func (ds *PostgresDatastore) Put(ctx context.Context, key, value []byte) error {
	_, err := ds.db.Exec(`
	    INSERT INTO extras (
			key,
			value
		)
		VALUES ($1, $2)
		ON CONFLICT (key) DO UPDATE SET
			value = $2;
		`, string(key), string(value))

	if err != nil {
		return err
	}

	return nil
}

func (ds *PostgresDatastore) Get(ctx context.Context, key []byte) ([]byte, error) {
	row := ds.db.QueryRow("SELECT value FROM extras WHERE key=$1", key)

	var value string
	err := row.Scan(&value)
	if err == sql.ErrNoRows {
		return nil, nil
	} else if err != nil {
		return nil, err
	}

	return []byte(value), nil
}

func (ds *PostgresDatastore) Tx(f func(*sql.Tx) error) error {
	tx, err := ds.db.Begin()
	if err != nil {
		return err
	}
	err = f(tx)
	if err != nil {
		tx.Rollback()
		return err
	}
	return tx.Commit()
}

func (ds *PostgresDatastore) InsertTask(ctx context.Context, task *models.Task) error {
	err := ds.Tx(func(tx *sql.Tx) error {
		_, err := tx.Exec(
			`INSERT INTO calls (
				id,
				created_at,
				started_at,
				completed_at,
				status,
				app_name,
				path) VALUES ($1, $2, $3, $4, $5, $6, $7);`,
			task.ID,
			task.CreatedAt.String(),
			task.StartedAt.String(),
			task.CompletedAt.String(),
			task.Status,
			task.AppName,
			task.Path,
		)
		return err
	})
	return err
}

func (ds *PostgresDatastore) GetTask(ctx context.Context, callID string) (*models.FnCall, error) {
	whereStm := "%s WHERE id=$1"

	return datastoreutil.SQLGetCall(ds.db, callSelector, callID, whereStm)
}

func (ds *PostgresDatastore) GetTasks(ctx context.Context, filter *models.CallFilter) (models.FnCalls, error) {
	whereStm := "WHERE %s $1"
	andStm := " AND %s $2"

	return datastoreutil.SQLGetCalls(ds.db, callSelector, filter, whereStm, andStm)
}