package utils

import (
	"fmt"

	authtx "cosmossdk.io/x/auth/tx"
	"cosmossdk.io/x/gov/types"
	v1 "cosmossdk.io/x/gov/types/v1"
	"cosmossdk.io/x/gov/types/v1beta1"

	"github.com/cosmos/cosmos-sdk/client"
	sdk "github.com/cosmos/cosmos-sdk/types"
)

const (
	defaultPage  = 1
	defaultLimit = 30 // should be consistent with https://github.com/cometbft/cometbft/tree/v0.37.x/rpc/core#pagination
)

// Proposer contains metadata of a governance proposal used for querying a
// proposer.
type Proposer struct {
	ProposalID uint64 `json:"proposal_id" yaml:"proposal_id"`
	Proposer   string `json:"proposer" yaml:"proposer"`
}

// NewProposer returns a new Proposer given id and proposer
func NewProposer(proposalID uint64, proposer string) Proposer {
	return Proposer{proposalID, proposer}
}

// String implements the fmt.Stringer interface.
func (p Proposer) String() string {
	return fmt.Sprintf("Proposal with ID %d was proposed by %s", p.ProposalID, p.Proposer)
}

// QueryProposalVotesParams is used to query 'custom/gov/votes'.
type QueryProposalVotesParams struct {
	ProposalID uint64
	Page       int
	Limit      int
}

// QueryVotesByTxQuery will query for votes via a direct txs tags query. It
// will fetch and build votes directly from the returned txs and returns a JSON
// marshaled result or any error that occurred.
func QueryVotesByTxQuery(clientCtx client.Context, params QueryProposalVotesParams) ([]byte, error) {
	var (
		votes      []*v1.Vote
		nextTxPage = defaultPage
		totalLimit = params.Limit * params.Page
	)

	// query interrupted either if we collected enough votes or tx indexer run out of relevant txs
	for len(votes) < totalLimit {
		// Search for both (legacy) votes and weighted votes.
		q := fmt.Sprintf("%s.%s='%d'", types.EventTypeProposalVote, types.AttributeKeyProposalID, params.ProposalID)
		searchResult, err := authtx.QueryTxsByEvents(clientCtx, nextTxPage, defaultLimit, q, "")
		if err != nil {
			return nil, err
		}

		for _, info := range searchResult.Txs {
			for _, msg := range info.GetTx().GetMsgs() {
				if voteMsg, ok := msg.(*v1beta1.MsgVote); ok {
					votes = append(votes, &v1.Vote{
						Voter:      voteMsg.Voter,
						ProposalId: params.ProposalID,
						Options:    v1.NewNonSplitVoteOption(v1.VoteOption(voteMsg.Option)),
					})
				}

				if voteMsg, ok := msg.(*v1.MsgVote); ok {
					votes = append(votes, &v1.Vote{
						Voter:      voteMsg.Voter,
						ProposalId: params.ProposalID,
						Options:    v1.NewNonSplitVoteOption(voteMsg.Option),
					})
				}

				if voteWeightedMsg, ok := msg.(*v1beta1.MsgVoteWeighted); ok {
					votes = append(votes, convertVote(voteWeightedMsg))
				}

				if voteWeightedMsg, ok := msg.(*v1.MsgVoteWeighted); ok {
					votes = append(votes, &v1.Vote{
						Voter:      voteWeightedMsg.Voter,
						ProposalId: params.ProposalID,
						Options:    voteWeightedMsg.Options,
					})
				}
			}
		}
		if len(searchResult.Txs) != defaultLimit {
			break
		}

		nextTxPage++
	}
	start, end := client.Paginate(len(votes), params.Page, params.Limit, 100)
	if start < 0 || end < 0 {
		votes = []*v1.Vote{}
	} else {
		votes = votes[start:end]
	}

	bz, err := clientCtx.LegacyAmino.MarshalJSON(votes)
	if err != nil {
		return nil, err
	}

	return bz, nil
}

// QueryVoteParams is used to query 'custom/gov/vote'
type QueryVoteParams struct {
	ProposalID uint64
	Voter      sdk.AccAddress
}

// QueryVoteByTxQuery will query for a single vote via a direct txs tags query.
func QueryVoteByTxQuery(clientCtx client.Context, params QueryVoteParams) ([]byte, error) {
	voterAddr, err := clientCtx.AddressCodec.BytesToString(params.Voter)
	if err != nil {
		return nil, err
	}

	q1 := fmt.Sprintf("%s.%s='%d'", types.EventTypeProposalVote, types.AttributeKeyProposalID, params.ProposalID)
	q2 := fmt.Sprintf("%s.%s='%s'", sdk.EventTypeMessage, sdk.AttributeKeySender, voterAddr)
	q3 := fmt.Sprintf("%s.%s='%s'", sdk.EventTypeMessage, sdk.AttributeKeySender, params.Voter)
	searchResult, err := authtx.QueryTxsByEvents(clientCtx, defaultPage, defaultLimit, fmt.Sprintf("%s AND (%s OR %s)", q1, q2, q3), "")
	if err != nil {
		return nil, err
	}

	for _, info := range searchResult.Txs {
		for _, msg := range info.GetTx().GetMsgs() {
			// there should only be a single vote under the given conditions
			var vote *v1.Vote
			if voteMsg, ok := msg.(*v1beta1.MsgVote); ok {
				vote = &v1.Vote{
					Voter:      voteMsg.Voter,
					ProposalId: params.ProposalID,
					Options:    v1.NewNonSplitVoteOption(v1.VoteOption(voteMsg.Option)),
				}
			}

			if voteMsg, ok := msg.(*v1.MsgVote); ok {
				vote = &v1.Vote{
					Voter:      voteMsg.Voter,
					ProposalId: params.ProposalID,
					Options:    v1.NewNonSplitVoteOption(voteMsg.Option),
				}
			}

			if voteWeightedMsg, ok := msg.(*v1beta1.MsgVoteWeighted); ok {
				vote = convertVote(voteWeightedMsg)
			}

			if voteWeightedMsg, ok := msg.(*v1.MsgVoteWeighted); ok {
				vote = &v1.Vote{
					Voter:      voteWeightedMsg.Voter,
					ProposalId: params.ProposalID,
					Options:    voteWeightedMsg.Options,
				}
			}

			if vote != nil {
				bz, err := clientCtx.Codec.MarshalJSON(vote)
				if err != nil {
					return nil, err
				}

				return bz, nil
			}
		}
	}

	return nil, fmt.Errorf("address '%s' did not vote on proposalID %d", params.Voter, params.ProposalID)
}

// convertVote converts a MsgVoteWeighted into a *v1.Vote.
func convertVote(v *v1beta1.MsgVoteWeighted) *v1.Vote {
	opts := make([]*v1.WeightedVoteOption, len(v.Options))
	for i, o := range v.Options {
		opts[i] = &v1.WeightedVoteOption{
			Option: v1.VoteOption(o.Option),
			Weight: o.Weight.String(),
		}
	}
	return &v1.Vote{
		Voter:      v.Voter,
		ProposalId: v.ProposalId,
		Options:    opts,
	}
}