package webapi

import (
	"time"

	"github.com/decred/vspd/database"
	"github.com/decred/vspd/rpc"
	"github.com/gin-gonic/gin"
)

// setVoteChoices is the handler for "POST /api/v3/setvotechoices".
func setVoteChoices(c *gin.Context) {
	funcName := "setVoteChoices"

	// Get values which have been added to context by middleware.
	ticket := c.MustGet("Ticket").(database.Ticket)
	knownTicket := c.MustGet("KnownTicket").(bool)
	walletClients := c.MustGet("WalletClients").([]*rpc.WalletRPC)

	// If we cannot set the vote choices on at least one voting wallet right
	// now, don't update the database, just return an error.
	if len(walletClients) == 0 {
		sendError(errInternalError, c)
		return
	}

	if !knownTicket {
		log.Warnf("%s: Unknown ticket (clientIP=%s)", funcName, c.ClientIP())
		sendError(errUnknownTicket, c)
		return
	}

	if ticket.FeeTxStatus == database.NoFee {
		log.Warnf("%s: No fee tx for ticket (clientIP=%s, ticketHash=%s)",
			funcName, c.ClientIP(), ticket.Hash)
		sendError(errFeeNotReceived, c)
		return
	}

	var request setVoteChoicesRequest
	if err := c.ShouldBindJSON(&request); err != nil {
		log.Warnf("%s: Bad request (clientIP=%s): %v", funcName, c.ClientIP(), err)
		sendErrorWithMsg(err.Error(), errBadRequest, c)
		return
	}

	voteChoices := request.VoteChoices
	err := isValidVoteChoices(cfg.NetParams, currentVoteVersion(cfg.NetParams), voteChoices)
	if err != nil {
		log.Warnf("%s: Invalid vote choices (clientIP=%s, ticketHash=%s): %v",
			funcName, c.ClientIP(), ticket.Hash, err)
		sendErrorWithMsg(err.Error(), errInvalidVoteChoices, c)
		return
	}

	// Update VoteChoices in the database before updating the wallets. DB is
	// source of truth and is less likely to error.
	ticket.VoteChoices = voteChoices
	err = db.UpdateTicket(ticket)
	if err != nil {
		log.Errorf("%s: db.UpdateTicket error, failed to set vote choices (ticketHash=%s): %v",
			funcName, ticket.Hash, err)
		sendError(errInternalError, c)
		return
	}

	// Update vote choices on voting wallets. Tickets are only added to voting
	// wallets if their fee is confirmed.
	if ticket.FeeTxStatus == database.FeeConfirmed {
		for agenda, choice := range voteChoices {
			for _, walletClient := range walletClients {
				err = walletClient.SetVoteChoice(agenda, choice, ticket.Hash)
				if err != nil {
					// If this fails, we still want to try the other wallets, so
					// don't return an error response, just log an error.
					log.Errorf("%s: dcrwallet.SetVoteChoice failed (wallet=%s, ticketHash=%s): %v",
						funcName, walletClient.String(), ticket.Hash, err)
				}
			}
		}
	}

	log.Debugf("%s: Vote choices updated (ticketHash=%s)", funcName, ticket.Hash)

	// TODO: DB - error if given timestamp is older than any previous requests

	// TODO: DB - store setvotechoices receipt in log

	sendJSONResponse(setVoteChoicesResponse{
		Timestamp: time.Now().Unix(),
		Request:   request,
	}, c)
}