package store

import (
	"context"
	"database/sql"
	"fmt"
	"time"

	"github.com/cosmic-clash/cosmic-clash/server/domain"
)

const ProposalExpireSQL = `UPDATE proposals
SET state = 'EXPIRED', revision = revision + 1
WHERE proposal_id = $1 AND state = 'OPEN' AND expires_at <= $2`

const ProposalParticipantExpireSQL = `UPDATE proposal_participants
SET response = 'TIMED_OUT', responded_at = $2
WHERE proposal_id = $1 AND response = 'PENDING'`

const ProposalRecoverySelectSQL = `SELECT proposal_id, playlist, state, revision, expires_at
FROM proposals
WHERE proposal_id = $1
  AND EXISTS (SELECT 1 FROM proposal_participants WHERE proposal_id = proposals.proposal_id AND player_id = $2)`

const ProposalParticipantsSelectSQL = `SELECT player_id, response
FROM proposal_participants
WHERE proposal_id = $1
ORDER BY player_id`

// GetProposal recovers the full proposal only after proving the caller is a
// participant. Expiry is advanced in the same transaction as the read so a
// missed event cannot leave a durable proposal indefinitely OPEN.
func GetProposal(ctx context.Context, db *sql.DB, playerID, proposalID string, now time.Time) (domain.Proposal, error) {
	if db == nil || playerID == "" || proposalID == "" || now.IsZero() {
		return domain.Proposal{}, fmt.Errorf("invalid proposal recovery arguments")
	}
	tx, err := db.BeginTx(ctx, nil)
	if err != nil {
		return domain.Proposal{}, err
	}
	defer tx.Rollback()
	if _, err := tx.ExecContext(ctx, ProposalExpireSQL, proposalID, now); err != nil {
		return domain.Proposal{}, err
	}
	if _, err := tx.ExecContext(ctx, ProposalParticipantExpireSQL, proposalID, now); err != nil {
		return domain.Proposal{}, err
	}
	var proposal domain.Proposal
	var playlist, state string
	if err := tx.QueryRowContext(ctx, ProposalRecoverySelectSQL, proposalID, playerID).Scan(&proposal.ProposalID, &playlist, &state, &proposal.Revision, &proposal.ExpiresAt); err != nil {
		return domain.Proposal{}, err
	}
	proposal.Playlist = domain.Playlist(playlist)
	proposal.State = domain.State(state)
	rows, err := tx.QueryContext(ctx, ProposalParticipantsSelectSQL, proposalID)
	if err != nil {
		return domain.Proposal{}, err
	}
	defer rows.Close()
	for rows.Next() {
		var participant domain.ProposalParticipant
		if err := rows.Scan(&participant.PlayerID, &participant.Response); err != nil {
			return domain.Proposal{}, err
		}
		proposal.Participants = append(proposal.Participants, participant)
	}
	if err := rows.Err(); err != nil {
		return domain.Proposal{}, err
	}
	if len(proposal.Participants) == 0 {
		return domain.Proposal{}, fmt.Errorf("proposal has no participants")
	}
	if err := tx.Commit(); err != nil {
		return domain.Proposal{}, err
	}
	return proposal, nil
}