package network

import (
	"bytes"
	"database/sql"
	"fmt"

	"github.com/status-im/status-go/params"
)

type CombinedNetwork struct {
	Prod *params.Network
	Test *params.Network
}

const baseQuery = "SELECT chain_id, chain_name, rpc_url, fallback_url, block_explorer_url, icon_url, native_currency_name, native_currency_symbol, native_currency_decimals, is_test, layer, enabled, chain_color, short_name, related_chain_id FROM networks"

func newNetworksQuery() *networksQuery {
	buf := bytes.NewBuffer(nil)
	buf.WriteString(baseQuery)
	return &networksQuery{buf: buf}
}

type networksQuery struct {
	buf   *bytes.Buffer
	args  []interface{}
	added bool
}

func (nq *networksQuery) andOrWhere() {
	if nq.added {
		nq.buf.WriteString(" AND")
	} else {
		nq.buf.WriteString(" WHERE")
	}
}

func (nq *networksQuery) filterEnabled(enabled bool) *networksQuery {
	nq.andOrWhere()
	nq.added = true
	nq.buf.WriteString(" enabled = ?")
	nq.args = append(nq.args, enabled)
	return nq
}

func (nq *networksQuery) filterChainID(chainID uint64) *networksQuery {
	nq.andOrWhere()
	nq.added = true
	nq.buf.WriteString(" chain_id = ?")
	nq.args = append(nq.args, chainID)
	return nq
}

func (nq *networksQuery) exec(db *sql.DB, configuredNetworks []params.Network) ([]*params.Network, error) {
	rows, err := db.Query(nq.buf.String(), nq.args...)
	if err != nil {
		return nil, err
	}
	var res []*params.Network
	defer rows.Close()
	for rows.Next() {
		network := params.Network{}
		err := rows.Scan(
			&network.ChainID, &network.ChainName, &network.RPCURL, &network.FallbackURL, &network.BlockExplorerURL, &network.IconURL,
			&network.NativeCurrencyName, &network.NativeCurrencySymbol,
			&network.NativeCurrencyDecimals, &network.IsTest, &network.Layer, &network.Enabled, &network.ChainColor, &network.ShortName,
			&network.RelatedChainID,
		)
		if err != nil {
			return nil, err
		}

		for _, configuredNetwork := range configuredNetworks {
			if configuredNetwork.ChainID == network.ChainID {
				if network.RPCURL == "" {
					network.RPCURL = configuredNetwork.RPCURL
				}
				network.OriginalRPCURL = configuredNetwork.RPCURL
				break
			}
		}

		for _, configuredNetwork := range configuredNetworks {
			if configuredNetwork.ChainID == network.ChainID {
				if network.FallbackURL == "" {
					network.FallbackURL = configuredNetwork.FallbackURL
				}
				network.OriginalFallbackURL = configuredNetwork.FallbackURL
				break
			}
		}
		res = append(res, &network)
	}

	return res, err
}

type Manager struct {
	db                 *sql.DB
	configuredNetworks []params.Network
}

func NewManager(db *sql.DB) *Manager {
	return &Manager{
		db: db,
	}
}

func find(chainID uint64, networks []params.Network) int {
	for i := range networks {
		if networks[i].ChainID == chainID {
			return i
		}
	}
	return -1
}

func (nm *Manager) Init(networks []params.Network) error {
	if networks == nil {
		return nil
	}
	nm.configuredNetworks = networks

	var errors string
	currentNetworks, _ := nm.Get(false)

	// Delete networks which are not supported any more
	for i := range currentNetworks {
		if find(currentNetworks[i].ChainID, networks) == -1 {
			err := nm.Delete(currentNetworks[i].ChainID)
			if err != nil {
				errors += fmt.Sprintf("error deleting network with ChainID: %d, %s", currentNetworks[i].ChainID, err.Error())
			}
		}
	}

	// Add new networks and update related chain id for the old ones
	for i := range networks {
		found := false
		for j := range currentNetworks {
			if currentNetworks[j].ChainID == networks[i].ChainID {
				found = true
				if currentNetworks[j].RelatedChainID != networks[i].RelatedChainID {
					// Update fallback_url if it's different
					err := nm.UpdateRelatedChainID(currentNetworks[j].ChainID, networks[i].RelatedChainID)
					if err != nil {
						errors += fmt.Sprintf("error updating network fallback_url for ChainID: %d, %s", currentNetworks[j].ChainID, err.Error())
					}
				}
				break
			}
		}

		if !found {
			// Add network if doesn't exist
			err := nm.Upsert(&networks[i])
			if err != nil {
				errors += fmt.Sprintf("error inserting network with ChainID: %d, %s", networks[i].ChainID, err.Error())
			}
		}
	}

	if len(errors) > 0 {
		return fmt.Errorf(errors)
	}

	return nil
}

func (nm *Manager) Upsert(network *params.Network) error {
	rpcURL := network.RPCURL
	fallbackURL := network.FallbackURL
	for _, n := range nm.configuredNetworks {
		if n.ChainID == network.ChainID {
			if rpcURL == n.RPCURL {
				rpcURL = ""
			}
			if fallbackURL == n.FallbackURL {
				fallbackURL = ""
			}
			break
		}
	}
	_, err := nm.db.Exec(
		"INSERT OR REPLACE INTO networks (chain_id, chain_name, rpc_url, fallback_url, block_explorer_url, icon_url, native_currency_name, native_currency_symbol, native_currency_decimals, is_test, layer, enabled, chain_color, short_name, related_chain_id) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
		network.ChainID, network.ChainName, rpcURL, fallbackURL, network.BlockExplorerURL, network.IconURL,
		network.NativeCurrencyName, network.NativeCurrencySymbol, network.NativeCurrencyDecimals,
		network.IsTest, network.Layer, network.Enabled, network.ChainColor, network.ShortName,
		network.RelatedChainID,
	)
	return err
}

func (nm *Manager) Delete(chainID uint64) error {
	_, err := nm.db.Exec("DELETE FROM networks WHERE chain_id = ?", chainID)
	return err
}

func (nm *Manager) UpdateRelatedChainID(chainID uint64, relatedChainID uint64) error {
	_, err := nm.db.Exec(`UPDATE networks SET related_chain_id = ? WHERE chain_id = ?`, relatedChainID, chainID)
	return err
}

func (nm *Manager) Find(chainID uint64) *params.Network {
	networks, err := newNetworksQuery().filterChainID(chainID).exec(nm.db, nm.configuredNetworks)
	if len(networks) != 1 || err != nil {
		return nil
	}
	return networks[0]
}

func (nm *Manager) Get(onlyEnabled bool) ([]*params.Network, error) {
	query := newNetworksQuery()
	if onlyEnabled {
		query.filterEnabled(true)
	}

	return query.exec(nm.db, nm.configuredNetworks)
}

func (nm *Manager) GetCombinedNetworks() ([]*CombinedNetwork, error) {
	query := newNetworksQuery()
	networks, err := query.exec(nm.db, nm.configuredNetworks)
	if err != nil {
		return nil, err
	}
	var combinedNetworks []*CombinedNetwork
	for _, network := range networks {
		found := false
		for _, n := range combinedNetworks {
			if (n.Test != nil && network.ChainID == n.Test.RelatedChainID) || (n.Prod != nil && network.ChainID == n.Prod.RelatedChainID) {
				found = true
				if network.IsTest {
					n.Test = network
					break
				} else {
					n.Prod = network
					break
				}
			}
		}

		if found {
			continue
		}

		newCombined := &CombinedNetwork{}
		if network.IsTest {
			newCombined.Test = network
		} else {
			newCombined.Prod = network
		}
		combinedNetworks = append(combinedNetworks, newCombined)
	}

	return combinedNetworks, nil
}

func (nm *Manager) GetConfiguredNetworks() []params.Network {
	return nm.configuredNetworks
}