package irmaclient

import (
	"encoding/json"
	"fmt"
	"github.com/timshannon/bolthold"
	"time"

	"github.com/privacybydesign/irmago"
	"go.etcd.io/bbolt"
)

// This file contains the update mechanism for Client
// as well as updates themselves.

type update struct {
	When    irma.Timestamp
	Number  int
	Success bool
	Error   *string
}

var clientUpdates = []func(client *Client) error{
	// 0: Convert old cardemu.xml Android storage to our own storage format
	nil, // No longer necessary as the Android app was deprecated long ago

	// 1: Adding scheme manager index, signature and public key
	// Check the signatures of all scheme managers, if any is not ok,
	// copy the entire irma_configuration folder from assets
	nil, // made irrelevant by irma_configuration-autocopying

	// 2: Rename config -> preferences
	nil, // No longer necessary

	// 3: Copy new irma_configuration out of assets
	nil, // made irrelevant by irma_configuration-autocopying

	// 4: For each keyshare server, include in its struct the identifier of its scheme manager
	nil, // No longer necessary

	// 5: Remove the test scheme manager which was erroneously included in a production build
	nil, // No longer necessary, also broke many unit tests

	// 6: Remove earlier log items of wrong format
	nil, // No longer necessary

	// 7: Concert log entries to bolthold database
	func(client *Client) error {
		var logs []*LogEntry
		var err error

		start := time.Now()
		fmt.Println(start.UnixNano(), "started")
		if err = client.storage.load(&logs, logsFile); err != nil {
			return err
		}

		loaded := time.Now()
		fmt.Println(loaded.Sub(start), "loaded")

		// Open one bolt transaction to process all our log entries in
		err = client.storage.db.Bolt().Update(func(tx *bbolt.Tx) error {
			for _, log := range logs {
				// As log.Request is a json.RawMessage it would not get updated to the new session request
				// format by re-marshaling the containing struct, as normal struct members would,
				// so update it manually now by marshaling the session request into it.
				req, err := log.SessionRequest()
				if err != nil {
					return err
				}
				log.Request, err = json.Marshal(req)
				if err != nil {
					return err
				}
				if err = client.storage.db.TxUpsert(tx, bolthold.NextSequence(), log); err != nil {
					return err
				}
			}
			return nil
		})

		done := time.Now()
		fmt.Println(done.Sub(loaded), "done converting", len(logs), "logs")

		return err
	},
}

// update performs any function from clientUpdates that has not
// already been executed in the past, keeping track of previously executed updates
// in the file at updatesFile.
func (client *Client) update() error {
	// Load and parse file containing info about already performed updates
	var err error
	if client.updates, err = client.storage.LoadUpdates(); err != nil {
		return err
	}

	// Perform all new updates
	for i := len(client.updates); i < len(clientUpdates); i++ {
		err = nil
		if clientUpdates[i] != nil {
			err = clientUpdates[i](client)
		}
		u := update{
			When:    irma.Timestamp(time.Now()),
			Number:  i,
			Success: err == nil,
		}
		if err != nil {
			str := err.Error()
			u.Error = &str
		}
		client.updates = append(client.updates, u)
		if err != nil {
			break
		}
	}

	storeErr := client.storage.StoreUpdates(client.updates)
	if storeErr != nil {
		return storeErr
	}
	return err
}