package casino

import (
	crand "crypto/rand"
	"encoding/binary"
	"fmt"
	"math/rand"
	"reflect"
	"sort"
	"strconv"
	"strings"
	"sync"
)

type Manager struct {
	mu       sync.Mutex
	tables   map[string]*Table
	machines map[string]*Machine
	rng      *rand.Rand
	// seed is the seed the manager's stream was created with, so a test can
	// assert that the entropy path really drew a fresh one.
	seed int64
}

// NewManager returns a Manager with DETERMINISTIC per-game RNG streams
// derived from seed. It is the test seam: a fixed seed must give fixed
// shoes, reels, and spins. Production uses NewManagerEntropy.
func NewManager(seed int64) *Manager { return newManager(seed) }

// NewManagerEntropy returns a Manager whose per-game RNG streams are seeded
// from crypto/rand. Casino outcomes must not be reconstructible from the
// clock: a wall-clock seed lets anyone who knows (or brute-forces) the
// startup nanosecond replay every shoe and reel stream, so a certified
// 0.97-RTP machine becomes an unlimited-credit one. The streams themselves
// stay math/rand (unbiased Intn/Shuffle) and each game keeps its own.
func NewManagerEntropy() *Manager { return newManager(entropySeed()) }

// entropySeed draws a fresh 63-bit seed from crypto/rand. A broken entropy
// source is fatal instead of silently degrading to a reconstructible clock
// seed: the casino's game integrity depends on it.
func entropySeed() int64 {
	var b [8]byte
	if _, err := crand.Read(b[:]); err != nil {
		panic(fmt.Sprintf("casino entropy seed: %v", err))
	}
	// A non-negative 63-bit value: math/rand accepts any int64 seed, and a
	// non-negative seed prints cleanly in diagnostics.
	return int64(binary.LittleEndian.Uint64(b[:]) >> 1)
}

func newManager(seed int64) *Manager {
	return &Manager{
		tables:   make(map[string]*Table),
		machines: make(map[string]*Machine),
		rng:      rand.New(rand.NewSource(seed)),
		seed:     seed,
	}
}

func tableKey(roomID int, tableID string) string {
	return fmt.Sprintf("%d:%s", roomID, tableID)
}

// EnsureMachine returns nil for an invalid or unsupported configuration.
// When a machine already exists for the room/ID, its live rules are
// replaced by the new configuration ONLY while it is idle (no seated
// player, so no wager can be discarded); an occupied machine keeps its
// live rules until it becomes idle again.
func (m *Manager) EnsureMachine(roomID int, cfg MachineConfig) *Machine {
	if cfg.Validate() != nil {
		return nil
	}
	cfg = cfg.Normalize()
	key := tableKey(roomID, cfg.ID)
	m.mu.Lock()
	defer m.mu.Unlock()
	if machine := m.machines[key]; machine != nil {
		// DeepEqual (not ==) so the *bool rule fields compare by value;
		// == would treat every freshly parsed config as different and
		// discard an idle machine on every room load.
		if reflect.DeepEqual(machine.Config, cfg) {
			return machine
		}
		if machine.idle() {
			if next := newMachine(roomID, cfg, rand.New(rand.NewSource(m.rng.Int63()))); next != nil {
				m.machines[key] = next
				return next
			}
			// Fall through to keep the live machine rather than drop a
			// functioning game for an invalid replacement.
		}
		return machine
	}
	// Only the manager consumes its RNG, under m.mu. Each game owns an
	// independent stream protected by that game's lock.
	machine := newMachine(roomID, cfg, rand.New(rand.NewSource(m.rng.Int63())))
	m.machines[key] = machine
	return machine
}

// EnsureTable returns nil for an invalid or unsupported configuration.
// When a table already exists for the room/ID, its live rules are replaced
// only while the table is idle (no seated players, so no wagers can be
// silently discarded); an occupied table keeps its live rules until idle.
func (m *Manager) EnsureTable(roomID int, cfg TableConfig) *Table {
	if cfg.Validate() != nil {
		return nil
	}
	cfg = cfg.Normalize()
	key := tableKey(roomID, cfg.ID)
	m.mu.Lock()
	defer m.mu.Unlock()
	if table := m.tables[key]; table != nil {
		if reflect.DeepEqual(table.Config, cfg) {
			return table
		}
		if table.idle() {
			next := newTable(roomID, cfg, rand.New(rand.NewSource(m.rng.Int63())))
			if next != nil {
				m.tables[key] = next
				return next
			}
			// Fall through to keep the live table rather than drop a
			// functioning game for an invalid replacement.
		}
		return table
	}
	table := newTable(roomID, cfg, rand.New(rand.NewSource(m.rng.Int63())))
	if table == nil {
		return nil
	}
	m.tables[key] = table
	return table
}

func (m *Manager) Table(roomID int, tableID string) *Table {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.tables[tableKey(roomID, tableID)]
}

// snapshotTables copies the live table list under the lock so callers can
// iterate without holding it (table methods take their own locks).
func (m *Manager) snapshotTables() []*Table {
	m.mu.Lock()
	tables := make([]*Table, 0, len(m.tables))
	for _, table := range m.tables {
		tables = append(tables, table)
	}
	m.mu.Unlock()
	return tables
}

func (m *Manager) snapshotMachines() []*Machine {
	m.mu.Lock()
	machines := make([]*Machine, 0, len(m.machines))
	for _, machine := range m.machines {
		machines = append(machines, machine)
	}
	m.mu.Unlock()
	return machines
}

func (m *Manager) Tick() []Event {
	tables := m.snapshotTables()
	sort.Slice(tables, func(i, j int) bool {
		if tables[i].RoomID != tables[j].RoomID {
			return tables[i].RoomID < tables[j].RoomID
		}
		return tables[i].Config.ID < tables[j].Config.ID
	})
	var events []Event
	for _, table := range tables {
		events = append(events, table.tick()...)
	}
	machines := m.snapshotMachines()
	sort.Slice(machines, func(i, j int) bool {
		if machines[i].RoomID != machines[j].RoomID {
			return machines[i].RoomID < machines[j].RoomID
		}
		return machines[i].Config.ID < machines[j].Config.ID
	})
	for _, machine := range machines {
		events = append(events, machine.tick()...)
	}
	return events
}

// withMachine runs fn against the named machine when it exists.
func (m *Manager) withMachine(roomID int, machineID string, fn func(*Machine) []Event) []Event {
	m.mu.Lock()
	machine := m.machines[tableKey(roomID, machineID)]
	m.mu.Unlock()
	if machine == nil {
		return nil
	}
	return fn(machine)
}

func (m *Manager) JoinMachine(roomID int, cfg MachineConfig, name string) []Event {
	machine := m.EnsureMachine(roomID, cfg)
	if machine == nil {
		return []Event{{RoomID: roomID, TableID: cfg.ID, Type: EventResult, PrivateTo: name, Message: "That game is not available here."}}
	}
	return machine.join(name)
}

func (m *Manager) SetMachineBet(roomID int, machineID, name string, amount int, wallet Wallet) []Event {
	return m.withMachine(roomID, machineID, func(machine *Machine) []Event {
		return machine.setBet(name, amount, wallet)
	})
}

func (m *Manager) StartMachine(roomID int, machineID, name string, wallet Wallet) []Event {
	return m.withMachine(roomID, machineID, func(machine *Machine) []Event {
		return machine.start(name, wallet)
	})
}

func (m *Manager) EnableMachineAutoBet(roomID int, machineID, name string, wallet Wallet) []Event {
	return m.withMachine(roomID, machineID, func(machine *Machine) []Event {
		return machine.enableAutoBet(name, wallet)
	})
}

func (m *Manager) StopMachineAutoBet(roomID int, machineID, name string) ([]Event, bool) {
	stopped := false
	events := m.withMachine(roomID, machineID, func(machine *Machine) []Event {
		events, ok := machine.stopAutoBet(name)
		stopped = ok
		return events
	})
	return events, stopped
}

func (m *Manager) LeaveMachine(roomID int, machineID, name string) []Event {
	return m.withMachine(roomID, machineID, func(machine *Machine) []Event {
		return machine.leave(name)
	})
}

func (m *Manager) Join(roomID int, cfg TableConfig, name string) []Event {
	table := m.EnsureTable(roomID, cfg)
	if table == nil {
		return []Event{{RoomID: roomID, TableID: cfg.ID, Type: EventResult, PrivateTo: name, Message: "That game is not available here."}}
	}
	return table.join(name)
}

func (m *Manager) Leave(roomID int, tableID, name string) []Event {
	if table := m.Table(roomID, tableID); table != nil {
		return table.leave(name)
	}
	return nil
}

func (m *Manager) Bet(roomID int, tableID, name, spot string, amount int, wallet Wallet) []Event {
	if table := m.Table(roomID, tableID); table != nil {
		return table.bet(name, spot, amount, wallet)
	}
	return []Event{{RoomID: roomID, TableID: tableID, Type: EventResult, Player: name, PrivateTo: name, Message: "That game is not available here."}}
}

func (m *Manager) Action(roomID int, tableID, name, action string) []Event {
	if table := m.Table(roomID, tableID); table != nil {
		return table.action(name, action)
	}
	return []Event{{RoomID: roomID, TableID: tableID, Type: EventResult, PrivateTo: name, Message: "That game is not available here."}}
}

func (m *Manager) Rebet(roomID int, tableID, name string) (string, int) {
	if table := m.Table(roomID, tableID); table != nil {
		return table.rebet(name)
	}
	return "", 0
}

// MarkDisconnected removes the player from every table and machine,
// forfeiting any wager they had committed, so seats free up immediately.
func (m *Manager) MarkDisconnected(name string) []Event {
	var events []Event
	for _, table := range m.snapshotTables() {
		events = append(events, table.markDisconnected(name)...)
	}
	for _, machine := range m.snapshotMachines() {
		events = append(events, machine.markDisconnected(name)...)
	}
	return events
}

func (m *Manager) Participation(name string) (*Table, bool) {
	m.mu.Lock()
	defer m.mu.Unlock()
	for _, table := range m.tables {
		if table.hasParticipant(name) {
			return table, true
		}
	}
	for _, machine := range m.machines {
		if machine.hasParticipant(name) {
			return nil, true
		}
	}
	return nil, false
}

func (m *Manager) MachineFor(name string) (*Machine, bool) {
	m.mu.Lock()
	defer m.mu.Unlock()
	for _, machine := range m.machines {
		if machine.hasParticipant(name) {
			return machine, true
		}
	}
	return nil, false
}

func (m *Manager) MachineBusy(name string) bool {
	m.mu.Lock()
	defer m.mu.Unlock()
	for _, machine := range m.machines {
		if machine.isBusy(name) {
			return true
		}
	}
	return false
}

// RefundAll resolves every outstanding wager by refunding committed stakes
// to their players and then closing each game's round. Graceful shutdown and
// room eviction use this: rounds cannot settle, so no player may lose a
// stake to the shutdown itself. Refunds go through the wallet (durable,
// journaled) and the refund events are returned for delivery.
//
// It is deliberately NOT a way to clear live tables: every game discards
// the round it refunded (seats keep their last bet only for "rebet", but
// phases, hands, spins, and timers are reset), so a refunded round cannot
// settle later and a second call refunds nothing. A caller that wants the
// games to keep playing must not use this.
func (m *Manager) RefundAll() []Event {
	var events []Event
	for _, table := range m.snapshotTables() {
		events = append(events, table.refundAll()...)
	}
	for _, machine := range m.snapshotMachines() {
		events = append(events, machine.refundAll()...)
	}
	return events
}

// RekeyRooms remaps every room-keyed table and machine per idMap
// (oldID -> newID): both the manager's map keys and each game's RoomID.
// Game state (wagers, rounds) is preserved — the games continue in the
// renamed room. Uses delete-all-then-set-all so a swap cannot clobber.
//
// Callers MUST run on the owner goroutine: each game's RoomID is mutated
// without taking that game's own lock, which is safe only because Tick and
// every command are owner-serialized too.
func (m *Manager) RekeyRooms(idMap map[int]int) {
	if len(idMap) == 0 {
		return
	}
	m.mu.Lock()
	defer m.mu.Unlock()
	// rekey parses a room:table key and returns the remapped key and room ID.
	// strings.Cut/strconv is used instead of fmt.Sscanf because a table or
	// machine ID may legally contain whitespace (validation rejects only
	// surrounding whitespace) and %s would stop at the first space, rebuilding
	// a corrupted key and orphaning the game.
	rekey := func(key string) (string, int, bool) {
		roomStr, tableID, found := strings.Cut(key, ":")
		if !found {
			return "", 0, false
		}
		roomID, err := strconv.Atoi(roomStr)
		if err != nil {
			return "", 0, false
		}
		newID, ok := idMap[roomID]
		if !ok || newID == roomID {
			return "", 0, false
		}
		return fmt.Sprintf("%d:%s", newID, tableID), newID, true
	}
	movedTables := make(map[string]*Table, len(m.tables))
	for key, table := range m.tables {
		if newKey, newRoomID, ok := rekey(key); ok {
			// The Table handle and the game share one *tableBase, so this
			// single assignment updates event routing for both.
			table.RoomID = newRoomID
			movedTables[newKey] = table
			delete(m.tables, key)
		}
	}
	for newKey, table := range movedTables {
		m.tables[newKey] = table
	}
	movedMachines := make(map[string]*Machine, len(m.machines))
	for key, machine := range m.machines {
		if newKey, newRoomID, ok := rekey(key); ok {
			machine.RoomID = newRoomID
			movedMachines[newKey] = machine
			delete(m.machines, key)
		}
	}
	for newKey, machine := range movedMachines {
		m.machines[newKey] = machine
	}
}

// EvictRoom removes every cached table and machine in roomID (graceful
// shutdown semantics for deleted/renumbered rooms): outstanding wagers are
// refunded through each game's refundAll before the entries drop.
func (m *Manager) EvictRoom(roomID int) []Event {
	prefix := fmt.Sprintf("%d:", roomID)
	// Snapshot the games under the manager lock, then refund OUTSIDE it:
	// refundAll appends to the money journal and saves character files, and
	// holding m.mu across that I/O blocks every casino command and Tick.
	type evictable interface{ refundAll() []Event }
	var evicted []evictable
	m.mu.Lock()
	for key, table := range m.tables {
		if strings.HasPrefix(key, prefix) {
			evicted = append(evicted, table)
			delete(m.tables, key)
		}
	}
	for key, machine := range m.machines {
		if strings.HasPrefix(key, prefix) {
			evicted = append(evicted, machine)
			delete(m.machines, key)
		}
	}
	m.mu.Unlock()
	var events []Event
	for _, game := range evicted {
		events = append(events, game.refundAll()...)
	}
	return events
}