botWebWars/backend/app/game.py

import asyncio
import random
import uuid
from typing import Dict, List, Optional, Set, Tuple
from app.config import settings
from app.models import (
    AvailableMovesResponse,
    BattleResult,
    BoardConfig,
    BoardState,
    DIRECTION_OFFSETS,
    MoveCheckResult,
    MoveResponse,
    Party,
    PartyDefeatResult,
    PartyInvite,
    Player,
    PlayerCreate,
    TurnInfo,
)

STANDARD_DIRECTIONS = [
    ("UP", 0, -1),
    ("UP_RIGHT", 1, -1),
    ("RIGHT", 1, 0),
    ("DOWN_RIGHT", 1, 1),
    ("DOWN", 0, 1),
    ("DOWN_LEFT", -1, 1),
    ("LEFT", -1, 0),
    ("UP_LEFT", -1, -1),
]


class GameEngine:
    def __init__(self):
        self._lock = asyncio.Lock()
        self.players: Dict[str, Player] = {}
        self.parties: Dict[str, Party] = {}
        self.invites: Dict[str, PartyInvite] = {}
        self.turn_order: List[str] = []
        self.current_turn_index: int = 0
        self.round_number: int = 1
        self.turn_number: int = 0

        self.config = BoardConfig(
            min_x=settings.GRID_MIN_X,
            max_x=settings.GRID_MAX_X,
            min_y=settings.GRID_MIN_Y,
            max_y=settings.GRID_MAX_Y,
            grid_cells_x=settings.GRID_MAX_X - settings.GRID_MIN_X,
            grid_cells_y=settings.GRID_MAX_Y - settings.GRID_MIN_Y,
        )

    def _get_occupied_coordinates(self) -> Dict[Tuple[int, int], Player]:
        return {(p.x, p.y): p for p in self.players.values()}

    def _find_random_free_position(self) -> Tuple[int, int]:
        occupied = self._get_occupied_coordinates()
        total_possible = (self.config.max_x - self.config.min_x + 1) * (
            self.config.max_y - self.config.min_y + 1
        )

        if len(occupied) >= total_possible:
            return (
                random.randint(self.config.min_x, self.config.max_x),
                random.randint(self.config.min_y, self.config.max_y),
            )

        for _ in range(100):
            rx = random.randint(self.config.min_x, self.config.max_x)
            ry = random.randint(self.config.min_y, self.config.max_y)
            if (rx, ry) not in occupied:
                return (rx, ry)

        all_coords = [
            (x, y)
            for x in range(self.config.min_x, self.config.max_x + 1)
            for y in range(self.config.min_y, self.config.max_y + 1)
            if (x, y) not in occupied
        ]
        return random.choice(all_coords)

    def _get_active_turn_actors(self) -> List[str]:
        # Return actors that can take turns: party leaders and solo players
        actors = []
        for pid in self.turn_order:
            p = self.players.get(pid)
            if not p:
                continue
            if not p.party_id or p.is_party_leader:
                actors.append(pid)
        return actors

    def _get_current_player(self) -> Optional[Player]:
        actors = self._get_active_turn_actors()
        if not actors:
            return None
        safe_index = self.current_turn_index % len(actors)
        player_id = actors[safe_index]
        return self.players.get(player_id)

    def _get_turn_info(self) -> TurnInfo:
        current = self._get_current_player()
        actors = self._get_active_turn_actors()
        return TurnInfo(
            current_player_id=current.id if current else None,
            current_player_name=current.name if current else None,
            round_number=self.round_number,
            turn_number=self.turn_number,
            turn_order=actors,
        )

    def _advance_turn(self):
        actors = self._get_active_turn_actors()
        if not actors:
            self.current_turn_index = 0
            return
        self.turn_number += 1
        self.current_turn_index = (self.current_turn_index + 1) % len(actors)
        if self.current_turn_index == 0:
            self.round_number += 1

    async def register_player(self, player_in: PlayerCreate) -> Player:
        async with self._lock:
            player_id = f"bot_{uuid.uuid4().hex[:8]}"
            x, y = self._find_random_free_position()

            player = Player(
                id=player_id,
                name=player_in.name,
                color=player_in.color,
                x=x,
                y=y,
                score=0,
                party_id=None,
                is_party_leader=False,
            )
            self.players[player_id] = player
            self.turn_order.append(player_id)
            return player

    async def get_player(self, player_id: str) -> Optional[Player]:
        async with self._lock:
            return self.players.get(player_id)

    async def get_all_players(self) -> List[Player]:
        async with self._lock:
            return list(self.players.values())

    async def remove_player(self, player_id: str) -> bool:
        async with self._lock:
            if player_id not in self.players:
                return False

            player = self.players[player_id]

            # If player was in a party, clean up party membership
            if player.party_id and player.party_id in self.parties:
                party = self.parties[player.party_id]
                if player_id in party.member_ids:
                    party.member_ids.remove(player_id)
                if party.leader_id == player_id:
                    if party.member_ids:
                        new_leader_id = random.choice(party.member_ids)
                        party.leader_id = new_leader_id
                        new_lead = self.players.get(new_leader_id)
                        if new_lead:
                            new_lead.is_party_leader = True
                            party.leader_name = new_lead.name
                    else:
                        del self.parties[party.id]
                elif not party.member_ids:
                    del self.parties[party.id]

            del self.players[player_id]

            if player_id in self.turn_order:
                self.turn_order.remove(player_id)

            actors = self._get_active_turn_actors()
            if actors:
                self.current_turn_index %= len(actors)
            else:
                self.current_turn_index = 0

            return True

    async def reset(self) -> None:
        async with self._lock:
            self.players.clear()
            self.parties.clear()
            self.invites.clear()
            self.turn_order.clear()
            self.current_turn_index = 0
            self.round_number = 1
            self.turn_number = 0

    async def get_board_state(self) -> BoardState:
        async with self._lock:
            players_list = list(self.players.values())
            parties_list = list(self.parties.values())
            return BoardState(
                config=self.config,
                player_count=len(players_list),
                players=players_list,
                parties=parties_list,
                turn=self._get_turn_info(),
            )

    # ==========================================
    # Party Logic & Graph Adjacency
    # ==========================================

    @staticmethod
    def _are_adjacent(p1: Player, p2: Player) -> bool:
        # Distance <= 1 (cardinal or diagonal Chebyshev distance)
        return max(abs(p1.x - p2.x), abs(p1.y - p2.y)) <= 1

    def _verify_party_connectivity(self, member_players: List[Player]) -> bool:
        """Verifies all party members form a single connected component where each is within 1 distance."""
        if len(member_players) <= 1:
            return True

        visited: Set[str] = set()
        queue = [member_players[0]]
        visited.add(member_players[0].id)

        while queue:
            curr = queue.pop(0)
            for other in member_players:
                if other.id not in visited and self._are_adjacent(curr, other):
                    visited.add(other.id)
                    queue.append(other)

        return len(visited) == len(member_players)

    async def form_party(
        self, member_ids: List[str], leader_id: str, name: Optional[str] = None
    ) -> Party:
        async with self._lock:
            if len(member_ids) < 2:
                raise ValueError("A party must have at least 2 members")
            if leader_id not in member_ids:
                raise ValueError("Agreed leader must be one of the party members")

            member_players: List[Player] = []
            for mid in member_ids:
                p = self.players.get(mid)
                if not p:
                    raise KeyError(f"Player '{mid}' not found")
                member_players.append(p)

            # Check adjacency / connected link
            if not self._verify_party_connectivity(member_players):
                raise ValueError(
                    "All party members must be linked within 1 distance of each other (directly or via connected teammates)."
                )

            # Clean up any existing party memberships
            for p in member_players:
                if p.party_id and p.party_id in self.parties:
                    old_party = self.parties[p.party_id]
                    if p.id in old_party.member_ids:
                        old_party.member_ids.remove(p.id)
                    if not old_party.member_ids:
                        del self.parties[old_party.id]

            party_id = f"party_{uuid.uuid4().hex[:8]}"
            leader = self.players[leader_id]
            party_name = name or f"Squad {leader.name}"

            party = Party(
                id=party_id,
                name=party_name,
                leader_id=leader_id,
                leader_name=leader.name,
                member_ids=list(member_ids),
            )

            for p in member_players:
                p.party_id = party_id
                p.is_party_leader = p.id == leader_id

            self.parties[party_id] = party
            return party

    async def invite_to_party(
        self,
        inviter_id: str,
        invitee_id: str,
        proposed_leader_id: str,
        party_name: Optional[str] = None,
    ) -> PartyInvite:
        async with self._lock:
            inviter = self.players.get(inviter_id)
            invitee = self.players.get(invitee_id)
            if not inviter or not invitee:
                raise KeyError("Inviter or invitee not found")

            # Must be adjacent to inviter or to at least one member of inviter's party
            eligible_hosts = [inviter]
            if inviter.party_id and inviter.party_id in self.parties:
                party = self.parties[inviter.party_id]
                eligible_hosts = [self.players[mid] for mid in party.member_ids if mid in self.players]

            is_adjacent = any(self._are_adjacent(invitee, host) for host in eligible_hosts)
            if not is_adjacent:
                raise ValueError(
                    f"Bot '{invitee.name}' is too far away. Must be within 1 distance of a party member to join."
                )

            invite_id = f"inv_{uuid.uuid4().hex[:8]}"
            invite = PartyInvite(
                id=invite_id,
                inviter_id=inviter_id,
                invitee_id=invitee_id,
                proposed_leader_id=proposed_leader_id,
                party_id=inviter.party_id,
            )
            self.invites[invite_id] = invite
            return invite

    async def respond_to_invite(self, invite_id: str, accept: bool) -> Optional[Party]:
        async with self._lock:
            invite = self.invites.get(invite_id)
            if not invite:
                raise KeyError(f"Invite '{invite_id}' not found")
            if invite.status != "pending":
                raise ValueError(f"Invite already {invite.status}")

            if not accept:
                invite.status = "rejected"
                return None

            invite.status = "accepted"
            inviter = self.players.get(invite.inviter_id)
            invitee = self.players.get(invite.invitee_id)
            if not inviter or not invitee:
                raise KeyError("Inviter or invitee no longer active")

            # If inviter is already in a party, add invitee to that party
            if inviter.party_id and inviter.party_id in self.parties:
                party = self.parties[inviter.party_id]
                if invitee.id not in party.member_ids:
                    party.member_ids.append(invitee.id)
                invitee.party_id = party.id
                # Set agreed leader
                if invite.proposed_leader_id in party.member_ids:
                    party.leader_id = invite.proposed_leader_id
                    for mid in party.member_ids:
                        p = self.players.get(mid)
                        if p:
                            p.is_party_leader = p.id == party.leader_id
                    party.leader_name = self.players[party.leader_id].name
                return party

            # Otherwise form new party with both
            members = [inviter.id, invitee.id]
            leader_id = invite.proposed_leader_id if invite.proposed_leader_id in members else inviter.id
            party_id = f"party_{uuid.uuid4().hex[:8]}"
            leader = self.players[leader_id]
            party = Party(
                id=party_id,
                name=f"Squad {leader.name}",
                leader_id=leader_id,
                leader_name=leader.name,
                member_ids=members,
            )
            inviter.party_id = party_id
            inviter.is_party_leader = inviter.id == leader_id
            invitee.party_id = party_id
            invitee.is_party_leader = invitee.id == leader_id
            self.parties[party_id] = party
            return party

    async def get_all_parties(self) -> List[Party]:
        async with self._lock:
            return list(self.parties.values())

    async def get_party(self, party_id: str) -> Optional[Party]:
        async with self._lock:
            return self.parties.get(party_id)

    # ==========================================
    # Movement Checking (Single bot or Party)
    # ==========================================

    def _check_move_internal(
        self,
        player: Player,
        dx: int,
        dy: int,
        direction_name: str,
        occupied_map: Dict[Tuple[int, int], Player],
    ) -> MoveCheckResult:
        # If player is part of a party and IS the leader, check if ALL members can translate by (dx, dy)
        if player.party_id and player.party_id in self.parties and player.is_party_leader:
            party = self.parties[player.party_id]
            party_members = [self.players[mid] for mid in party.member_ids if mid in self.players]
            party_member_ids = {m.id for m in party_members}

            for m in party_members:
                tx = m.x + dx
                ty = m.y + dy

                # Wall boundary
                if tx < self.config.min_x or tx > self.config.max_x or ty < self.config.min_y or ty > self.config.max_y:
                    return MoveCheckResult(
                        direction=direction_name,
                        dx=dx,
                        dy=dy,
                        target_x=player.x + dx,
                        target_y=player.y + dy,
                        available=False,
                        reason=f"Party member '{m.name}' would hit boundary wall at ({tx}, {ty}).",
                    )

                # Collision with non-party bot
                occupant = occupied_map.get((tx, ty))
                if occupant is not None and occupant.id not in party_member_ids:
                    return MoveCheckResult(
                        direction=direction_name,
                        dx=dx,
                        dy=dy,
                        target_x=player.x + dx,
                        target_y=player.y + dy,
                        available=False,
                        reason=f"Party member '{m.name}' path blocked by '{occupant.name}' at ({tx}, {ty}).",
                    )

            return MoveCheckResult(
                direction=direction_name,
                dx=dx,
                dy=dy,
                target_x=player.x + dx,
                target_y=player.y + dy,
                available=True,
                reason=None,
            )

        # Single player or non-leader
        target_x = player.x + dx
        target_y = player.y + dy

        if target_x < self.config.min_x or target_x > self.config.max_x or target_y < self.config.min_y or target_y > self.config.max_y:
            return MoveCheckResult(
                direction=direction_name,
                dx=dx,
                dy=dy,
                target_x=target_x,
                target_y=target_y,
                available=False,
                reason=f"Wall collision at ({target_x}, {target_y}).",
            )

        occupant = occupied_map.get((target_x, target_y))
        if occupant is not None and occupant.id != player.id:
            return MoveCheckResult(
                direction=direction_name,
                dx=dx,
                dy=dy,
                target_x=target_x,
                target_y=target_y,
                available=False,
                reason=f"Space occupied by {occupant.name} ({occupant.id}) at ({target_x}, {target_y}).",
            )

        return MoveCheckResult(
            direction=direction_name,
            dx=dx,
            dy=dy,
            target_x=target_x,
            target_y=target_y,
            available=True,
            reason=None,
        )

    async def check_single_move(self, player_id: str, direction_input: str) -> MoveCheckResult:
        async with self._lock:
            player = self.players.get(player_id)
            if not player:
                raise KeyError(f"Player '{player_id}' not found")

            # Non-leaders cannot move independently
            if player.party_id and not player.is_party_leader:
                party = self.parties.get(player.party_id)
                leader_name = party.leader_name if party else "Leader"
                return MoveCheckResult(
                    direction=direction_input,
                    dx=0,
                    dy=0,
                    target_x=player.x,
                    target_y=player.y,
                    available=False,
                    reason=f"Only party leader '{leader_name}' controls movement for the party.",
                )

            normalized = direction_input.strip().upper().replace(" ", "_")
            if normalized not in DIRECTION_OFFSETS:
                raise ValueError(
                    f"Unknown direction '{direction_input}'. Allowed: UP, DOWN, LEFT, RIGHT, UP_LEFT, UP_RIGHT, DOWN_LEFT, DOWN_RIGHT"
                )

            dx, dy = DIRECTION_OFFSETS[normalized]
            occupied = self._get_occupied_coordinates()
            return self._check_move_internal(player, dx, dy, normalized, occupied)

    async def get_available_moves(self, player_id: str) -> AvailableMovesResponse:
        async with self._lock:
            player = self.players.get(player_id)
            if not player:
                raise KeyError(f"Player '{player_id}' not found")

            current_turn_player = self._get_current_player()
            is_turn = current_turn_player is not None and current_turn_player.id == player_id
            occupied = self._get_occupied_coordinates()

            party = self.parties.get(player.party_id) if player.party_id else None
            is_leader = player.is_party_leader or party is None
            member_count = len(party.member_ids) if party else 1

            moves: Dict[str, MoveCheckResult] = {}
            for name, dx, dy in STANDARD_DIRECTIONS:
                if player.party_id and not player.is_party_leader:
                    moves[name] = MoveCheckResult(
                        direction=name,
                        dx=dx,
                        dy=dy,
                        target_x=player.x + dx,
                        target_y=player.y + dy,
                        available=False,
                        reason=f"Only party leader '{party.leader_name if party else 'Leader'}' controls group movement.",
                    )
                else:
                    moves[name] = self._check_move_internal(player, dx, dy, name, occupied)

            return AvailableMovesResponse(
                player_id=player.id,
                player_name=player.name,
                current_x=player.x,
                current_y=player.y,
                is_turn=is_turn and is_leader,
                is_party_leader=player.is_party_leader,
                party_id=player.party_id,
                party_member_count=member_count,
                current_turn_player_id=current_turn_player.id if current_turn_player else None,
                moves=moves,
            )

    async def move_player(
        self, player_id: str, dx: int, dy: int, direction_name: str
    ) -> MoveResponse:
        async with self._lock:
            player = self.players.get(player_id)
            if not player:
                raise KeyError(f"Player '{player_id}' not found")

            # Non-leaders cannot move
            if player.party_id and not player.is_party_leader:
                party = self.parties.get(player.party_id)
                leader_name = party.leader_name if party else "Leader"
                raise PermissionError(
                    f"Party member '{player.name}' cannot move individually. Only party leader '{leader_name}' controls movement for the party."
                )

            current_turn_player = self._get_current_player()
            if not current_turn_player or current_turn_player.id != player_id:
                curr_name = current_turn_player.name if current_turn_player else "Nobody"
                curr_id = current_turn_player.id if current_turn_player else "None"
                raise PermissionError(
                    f"It is not your turn. Current turn belongs to '{curr_name}' ({curr_id})."
                )

            occupied = self._get_occupied_coordinates()
            check = self._check_move_internal(player, dx, dy, direction_name, occupied)

            if not check.available:
                raise ValueError(f"Illegal move: {check.reason}")

            prev_pos = {"x": player.x, "y": player.y}
            affected_players: List[Player] = []

            # If party leader, move all party members in unison
            if player.party_id and player.party_id in self.parties:
                party = self.parties[player.party_id]
                for mid in party.member_ids:
                    m = self.players.get(mid)
                    if m:
                        m.x += dx
                        m.y += dy
                        affected_players.append(m)
            else:
                player.x = check.target_x
                player.y = check.target_y
                affected_players.append(player)

            new_pos = {"x": player.x, "y": player.y}

            self._advance_turn()
            turn_info = self._get_turn_info()

            return MoveResponse(
                success=True,
                player=player,
                direction=direction_name,
                party_moved=bool(player.party_id),
                affected_players=affected_players,
                previous_position=prev_pos,
                new_position=new_pos,
                turn=turn_info,
            )

    async def pass_turn(self, player_id: str) -> TurnInfo:
        async with self._lock:
            player = self.players.get(player_id)
            if not player:
                raise KeyError(f"Player '{player_id}' not found")

            current_turn_player = self._get_current_player()
            if not current_turn_player or current_turn_player.id != player_id:
                curr_name = current_turn_player.name if current_turn_player else "Nobody"
                curr_id = current_turn_player.id if current_turn_player else "None"
                raise PermissionError(
                    f"Cannot pass: it is not your turn. Current turn belongs to '{curr_name}' ({curr_id})."
                )

            self._advance_turn()
            return self._get_turn_info()

    # ==========================================
    # Battle & Party Defeat Logic
    # ==========================================

    async def defeat_party(self, party_id: str) -> PartyDefeatResult:
        """Kills the party leader: score -= 1, respawns at random position, removed from party,

        and randomly assigns a new leader from the remainder of the party.
        """
        async with self._lock:
            party = self.parties.get(party_id)
            if not party:
                raise KeyError(f"Party '{party_id}' not found")

            old_leader_id = party.leader_id
            leader = self.players.get(old_leader_id)
            if not leader:
                raise KeyError(f"Leader '{old_leader_id}' not found")

            # 1. Leader killed: score goes down by 1
            leader.score -= 1

            # 2. Leader is removed from party
            leader.party_id = None
            leader.is_party_leader = False
            if old_leader_id in party.member_ids:
                party.member_ids.remove(old_leader_id)

            # 3. Leader respawns at random free position
            rx, ry = self._find_random_free_position()
            leader.x = rx
            leader.y = ry
            respawn_pos = {"x": rx, "y": ry}

            # 4. New leader is randomly assigned from the remainder of the party
            new_leader_id = None
            new_leader_name = None
            party_dissolved = False

            if len(party.member_ids) > 0:
                new_leader_id = random.choice(party.member_ids)
                party.leader_id = new_leader_id
                new_leader = self.players[new_leader_id]
                new_leader.is_party_leader = True
                new_leader_name = new_leader.name
                party.leader_name = new_leader_name
            else:
                # No members left in party
                del self.parties[party_id]
                party_dissolved = True

            return PartyDefeatResult(
                party_id=party_id,
                killed_leader_id=leader.id,
                killed_leader_name=leader.name,
                killed_leader_new_score=leader.score,
                killed_leader_respawn_position=respawn_pos,
                new_leader_id=new_leader_id,
                new_leader_name=new_leader_name,
                remaining_members=list(party.member_ids),
                party_dissolved=party_dissolved,
            )

    async def battle(self, challenger_id: str, defender_id: str) -> BattleResult:
        """Resolves a battle between two adjacent players/bots.

        The losing party's leader is killed, respawns, score -1, and remainder assigns new leader.
        """
        async with self._lock:
            p1 = self.players.get(challenger_id)
            p2 = self.players.get(defender_id)
            if not p1 or not p2:
                raise KeyError("Both combatants must exist")

            if p1.party_id and p1.party_id == p2.party_id:
                raise ValueError("Cannot battle your own party member")

            if not self._are_adjacent(p1, p2):
                raise ValueError(
                    f"Players are not adjacent. Combat distance must be <= 1 (current distance: ({abs(p1.x - p2.x)}, {abs(p1.y - p2.y)}))"
                )

            # Party size calculation for battle advantage
            size1 = len(self.parties[p1.party_id].member_ids) if p1.party_id and p1.party_id in self.parties else 1
            size2 = len(self.parties[p2.party_id].member_ids) if p2.party_id and p2.party_id in self.parties else 1

            if size1 > size2:
                winner, loser = p1, p2
            elif size2 > size1:
                winner, loser = p2, p1
            else:
                # Tied party sizes: 50/50 roll
                if random.random() < 0.5:
                    winner, loser = p1, p2
                else:
                    winner, loser = p2, p1

            # Winner score +1
            winner.score += 1

            # Resolve defeat for loser
            if loser.party_id and loser.party_id in self.parties:
                # Must release lock temporarily or run defeat internally
                party_id = loser.party_id
                party = self.parties[party_id]
                old_leader_id = party.leader_id
                leader = self.players[old_leader_id]
                leader.score -= 1
                leader.party_id = None
                leader.is_party_leader = False
                if old_leader_id in party.member_ids:
                    party.member_ids.remove(old_leader_id)

                rx, ry = self._find_random_free_position()
                leader.x = rx
                leader.y = ry
                respawn_pos = {"x": rx, "y": ry}

                new_leader_id = None
                new_leader_name = None
                party_dissolved = False

                if len(party.member_ids) > 0:
                    new_leader_id = random.choice(party.member_ids)
                    party.leader_id = new_leader_id
                    new_leader = self.players[new_leader_id]
                    new_leader.is_party_leader = True
                    new_leader_name = new_leader.name
                    party.leader_name = new_leader_name
                else:
                    del self.parties[party_id]
                    party_dissolved = True

                defeat_result = PartyDefeatResult(
                    party_id=party_id,
                    killed_leader_id=leader.id,
                    killed_leader_name=leader.name,
                    killed_leader_new_score=leader.score,
                    killed_leader_respawn_position=respawn_pos,
                    new_leader_id=new_leader_id,
                    new_leader_name=new_leader_name,
                    remaining_members=list(party.member_ids),
                    party_dissolved=party_dissolved,
                )
            else:
                # Solo loser
                loser.score -= 1
                rx, ry = self._find_random_free_position()
                loser.x = rx
                loser.y = ry
                defeat_result = PartyDefeatResult(
                    party_id="none",
                    killed_leader_id=loser.id,
                    killed_leader_name=loser.name,
                    killed_leader_new_score=loser.score,
                    killed_leader_respawn_position={"x": rx, "y": ry},
                    new_leader_id=None,
                    new_leader_name=None,
                    remaining_members=[],
                    party_dissolved=True,
                )

            return BattleResult(
                winner_id=winner.id,
                winner_name=winner.name,
                loser_id=loser.id,
                loser_name=loser.name,
                defeat_details=defeat_result,
            )


# Global game engine instance
game_engine = GameEngine()