package store

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

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

const ProposalInsertSQL = `INSERT INTO proposals
    (proposal_id, playlist, state, expires_at, revision, match_region, match_protocol)
VALUES ($1, $2, 'OPEN', $3, 0, NULLIF($4, ''), NULLIF($5, 0))`

// CreateProposal atomically claims the queue tickets and creates the proposal.
// Every statement runs inside the same SERIALIZABLE retry callback; callers
// must never publish a proposal from a cache-only candidate list.
func CreateProposal(ctx context.Context, db *sql.DB, proposal domain.Proposal, ticketIDs map[string]string, now time.Time) error {
	if proposal.ProposalID == "" || len(proposal.Participants) == 0 {
		return fmt.Errorf("invalid proposal transaction")
	}
	if !validProposalMatchPlan(proposal) {
		return fmt.Errorf("invalid proposal match plan")
	}
	return RunSerializable(ctx, db, DefaultSerializableAttempts, func(ctx context.Context, tx *sql.Tx) error {
		if _, err := tx.ExecContext(ctx, ProposalInsertSQL, proposal.ProposalID, proposal.Playlist, proposal.ExpiresAt, proposal.Region, proposal.Protocol); err != nil {
			return err
		}
		for _, participant := range proposal.Participants {
			ticketID := ticketIDs[participant.PlayerID]
			if participant.PlayerID == "" || ticketID == "" {
				return fmt.Errorf("missing proposal ticket mapping")
			}
			if _, err := tx.ExecContext(ctx, ProposalParticipantInsertSQL, proposal.ProposalID, participant.PlayerID, ticketID, nullablePlanField(proposal.Region != "", participant.Team), nullablePlanField(proposal.Region != "", participant.Slot)); err != nil {
				return err
			}
			result, err := tx.ExecContext(ctx, QueueTicketProposeSQL, ticketID, participant.PlayerID, string(proposal.Playlist), now)
			if err != nil {
				return err
			}
			changed, err := result.RowsAffected()
			if err != nil {
				return err
			}
			if changed != 1 {
				return fmt.Errorf("queue ticket claim lost")
			}
		}
		return nil
	})
}

func validProposalMatchPlan(proposal domain.Proposal) bool {
	if proposal.Region == "" && proposal.Protocol == 0 {
		return true // Legacy/direct callers have no matcher formation to persist.
	}
	if (proposal.Region != "EU" && proposal.Region != "NA") || proposal.Protocol < 1 {
		return false
	}
	seenSlots := make(map[int]struct{}, len(proposal.Participants))
	teams := [2]int{}
	for _, participant := range proposal.Participants {
		if participant.Team < 0 || participant.Team > 1 || participant.Slot < 0 || participant.Slot > 5 {
			return false
		}
		if _, exists := seenSlots[participant.Slot]; exists {
			return false
		}
		seenSlots[participant.Slot] = struct{}{}
		teams[participant.Team]++
	}
	return teams[0] > 0 && teams[1] > 0
}

func nullablePlanField(enabled bool, value int) any {
	if !enabled {
		return nil
	}
	return value
}