package rpc

import (
	"errors"

	"github.com/cosmos/cosmos-sdk/client/context"

	ethtypes "github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/eth/filters"
	"github.com/ethereum/go-ethereum/rpc"
)

// PublicFilterAPI is the eth_ prefixed set of APIs in the Web3 JSON-RPC spec.
type PublicFilterAPI struct {
	cliCtx  context.CLIContext
	backend Backend
	filters map[rpc.ID]*Filter // ID to filter; TODO: change to sync.Map in case of concurrent writes
}

// NewPublicEthAPI creates an instance of the public ETH Web3 API.
func NewPublicFilterAPI(cliCtx context.CLIContext, backend Backend) *PublicFilterAPI {
	return &PublicFilterAPI{
		cliCtx:  cliCtx,
		backend: backend,
		filters: make(map[rpc.ID]*Filter),
	}
}

// NewFilter instantiates a new filter.
func (e *PublicFilterAPI) NewFilter(criteria filters.FilterCriteria) rpc.ID {
	id := rpc.NewID()
	e.filters[id] = NewFilter(e.backend, &criteria)
	return id
}

// NewBlockFilter instantiates a new block filter.
func (e *PublicFilterAPI) NewBlockFilter() rpc.ID {
	id := rpc.NewID()
	e.filters[id] = NewBlockFilter(e.backend)
	return id
}

// NewPendingTransactionFilter instantiates a new pending transaction filter.
func (e *PublicFilterAPI) NewPendingTransactionFilter() rpc.ID {
	id := rpc.NewID()
	e.filters[id] = NewPendingTransactionFilter(e.backend)
	return id
}

// UninstallFilter uninstalls a filter with the given ID.
func (e *PublicFilterAPI) UninstallFilter(id rpc.ID) bool {
	e.filters[id].uninstallFilter()
	delete(e.filters, id)
	return true
}

// GetFilterChanges returns an array of changes since the last poll.
// If the filter is a log filter, it returns an array of Logs.
// If the filter is a block filter, it returns an array of block hashes.
// If the filter is a pending transaction filter, it returns an array of transaction hashes.
func (e *PublicFilterAPI) GetFilterChanges(id rpc.ID) (interface{}, error) {
	if e.filters[id] == nil {
		return nil, errors.New("invalid filter ID")
	}
	return e.filters[id].getFilterChanges()
}

// GetFilterLogs returns an array of all logs matching filter with given id.
func (e *PublicFilterAPI) GetFilterLogs(id rpc.ID) ([]*ethtypes.Log, error) {
	return e.filters[id].getFilterLogs()
}

// GetLogs returns logs matching the given argument that are stored within the state.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getlogs
func (e *PublicFilterAPI) GetLogs(criteria filters.FilterCriteria) ([]*ethtypes.Log, error) {
	filter := NewFilter(e.backend, &criteria)
	return filter.getFilterLogs()
}