package dnfbridge

import (
	"fmt"
	"math/rand/v2"

	"longheng.io/server/internal/modules/dnf/dnfenum"
	dnfpvf "longheng.io/server/internal/modules/dnf/pvf"
)

func currentPVPStartMapOrder(source initialEquipmentTextSource) ([]int64, error) {
	text, err := source.ReadText("etc/pvpmapbasicdata.etc")
	if err != nil {
		return nil, err
	}
	doc, err := dnfpvf.Parse("etc/pvpmapbasicdata.etc", text)
	if err != nil {
		return nil, err
	}
	order := doc.Ints("pvp map order")
	// Native map indices address this vector directly; 50000 is the random row.
	if len(order) < 2 || len(order) > 255 || order[0] != 50000 {
		return nil, fmt.Errorf("PVP map order has invalid length %d", len(order))
	}
	seen := make(map[int64]bool, len(order))
	for _, id := range order {
		if id <= 0 || seen[id] {
			return nil, fmt.Errorf("invalid or duplicate PVP map %d", id)
		}
		seen[id] = true
	}
	return order, nil
}

func (s *Service) startCurrentPVPRoomLocked(room *currentPVPRoom, owner *gameSession) error {
	reject := func(code byte, reason string) error {
		s.logGameEvent(owner, "game-pvp-start-rejected", "room_id", room.id, "reason", reason)
		return s.sendGameUpperFailure(owner, uint16(dnfenum.CmdPacketSetPVPReadyState), code)
	}
	if room.started || room.seatFor(owner) != int(room.manager) {
		return nil
	}
	if room.isPractice() {
		// sub_1FD8F50 starts practice locally via manager+164(state 10).
		// It does not send C2S53 or use the ordinary op45 match loader.
		return reject(19, "practice_mode_has_separate_start")
	}
	if room.battleMode == 8 {
		if len(room.totalCombatants()) != 2 {
			return reject(19, "total_match_requires_two_owners")
		}
		if err := s.refreshCurrentPVPTotalRoomLocked(room); err != nil {
			s.logGameEvent(owner, "game-pvp-total-roster-unavailable", "error", err)
			return reject(19, "total_match_roster_unavailable")
		}
	}
	combatants, red, blue := 0, 0, 0
	for seat, member := range room.members {
		if member == nil || room.seatState[seat] == 3 || room.seatState[seat] == 4 {
			continue
		}
		combatants++
		if seat != int(room.manager) && room.ready[seat] == 0 {
			return reject(22, "player_not_ready")
		}
		if room.seatState[seat] == 1 {
			red++
		}
		if room.seatState[seat] == 2 {
			blue++
		}
	}
	if combatants < 2 {
		return reject(22, "fewer_than_two_combatants")
	}
	if (room.battleMode == 2 || room.battleMode == 3 || room.battleMode == 5 || room.battleMode == 8) && (red == 0 || red != blue) {
		return reject(14, "unbalanced_teams")
	}
	if s.pvpMapOrder == nil {
		s.initialEquipmentMu.Lock()
		archive, err := s.initialEquipmentArchiveLocked()
		s.initialEquipmentMu.Unlock()
		if err == nil {
			s.pvpMapOrder, err = currentPVPStartMapOrder(archive)
		}
		if err != nil {
			return reject(19, "runtime_pvp_map_list_unavailable")
		}
	}
	selected := int(room.request.mapIndex)
	if selected < 0 || selected >= len(s.pvpMapOrder) {
		return reject(19, "map_index_out_of_range")
	}
	if selected == 0 {
		selected = 1 + rand.IntN(len(s.pvpMapOrder)-1)
	}
	room.match = &currentPVPMatch{winner: 0xff, startedAt: s.gameplayNow()}
	if room.battleMode == 8 {
		room.match.total = newCurrentPVPTotalMatch()
	}
	room.started = true
	room.ready[room.manager] = 1
	for _, member := range room.members {
		if member == nil {
			continue
		}
		if err := s.sendGameUpperRawClass(member.session, 44, []byte{room.manager, 1}, 0); err != nil {
			return err
		}
		// sub_1D68000 reads precisely u8 selected-map-index + u8 battle-mode.
		if err := s.sendGameUpperRawClass(member.session, 45, []byte{byte(selected), room.battleMode}, 0); err != nil {
			return err
		}
	}
	s.broadcastCurrentPVPPacketLocked(room, nil, currentPVPRoomStateMsgID,
		buildCurrentPVPRoomStateBody(room.id, room.state(), room.manager, room.request.mapIndex, room.battleMode, 0))
	s.logGameEvent(owner, "game-pvp-start-complete", "room_id", room.id, "map_index", selected,
		"map_id", s.pvpMapOrder[selected], "battle_mode", room.battleMode, "combatants", combatants,
		"sequence", "op44_ready_op45_start_op42_started")
	if room.match.total != nil {
		return s.scheduleCurrentPVPTotalPhaseLocked(room, false)
	}
	return nil
}

func (s *Service) handleCurrentPVPMatchSignal(session *gameSession, opcode uint16, body []byte) error {
	if session == nil || !isPVPChannel(session.channel) {
		return nil
	}
	valid := len(body) == 0
	if opcode == uint16(dnfenum.CmdPacketConnectP2pPVP) {
		valid = len(body) > 0 && body[0] <= currentPVPRoomSeatCount && len(body) == 1+2*int(body[0])
		if valid {
			var seen [currentPVPRoomSeatCount]bool
			for i := 1; i < len(body); i += 2 {
				seat := body[i]
				if seat >= currentPVPRoomSeatCount || body[i+1] > 1 || seen[seat] {
					valid = false
					break
				}
				seen[seat] = true
			}
		}
	}
	if !valid {
		return nil
	}
	s.pvpMu.Lock()
	defer s.pvpMu.Unlock()
	if room := session.pvpRoom; room != nil && room.started {
		if room.battleMode == 8 {
			return s.handleCurrentPVPTotalLoadLocked(room, session, opcode)
		}
		// Normal matches advance locally after op45; league-specific replies
		// and generic unsupported-command failures interrupt the native loader.
		s.logGameEvent(session, "game-pvp-match-signal", "room_id", room.id, "opcode", opcode, "body_len", len(body))
	}
	return nil
}