package game

// Regression: returning the equipped ammo stack to the inventory must never
// delete it. The equipment entry may only be cleared once the stack has been
// merged into an inventory stack or placed in a free slot, so a full
// inventory refuses the swap/removal instead of losing the ammo. The previous
// code deleted Equipment[SlotAmmo] and zeroed AmmoQty unconditionally.

import (
	"path/filepath"
	"strings"
	"testing"

	"thehouseoficarus/internal/item"
	"thehouseoficarus/internal/net"
	"thehouseoficarus/internal/player"
)

const (
	hardeningArrowsID = "test_arrows"
	hardeningBoltsID  = "test_bolts"
)

// seedAmmoItems installs two stackable ammo items so a swap has a target.
func seedAmmoItems(t *testing.T, h *harness) {
	t.Helper()
	writeSeedFile(t, filepath.Join(h.dir, "items", hardeningArrowsID+".yaml"),
		[]byte("id: test_arrows\nname: test arrows\nstackable: true\nequipment:\n  type: ammo\n  slot: ammo\n"))
	writeSeedFile(t, filepath.Join(h.dir, "items", hardeningBoltsID+".yaml"),
		[]byte("id: test_bolts\nname: test bolts\nstackable: true\nequipment:\n  type: ammo\n  slot: ammo\n"))
}

// fillAllSlots occupies every inventory slot and returns the session used by
// the wear/remove paths.
func fillAllSlots(p *player.Player) *net.Session {
	for i := 0; i < 28; i++ {
		p.SetInvSlot(i, &player.InventorySlot{ItemID: "filler", Quantity: 1})
	}
	sess := &net.Session{Conn: newChanConn(), Player: p}
	sess.SetState(net.StateGame)
	return sess
}

func TestUnequipAmmoSwapKeepsStackWhenInventoryFull(t *testing.T) {
	h := newHarness(t)
	h.seedAccount("alice")
	p := h.seedCharacter("alice", "alice")
	seedAmmoItems(t, h)
	h.g.RunOnOwner(func() {
		h.g.ItemStore.Reload(h.dir)
		sess := fillAllSlots(p)
		p.SetInvSlot(3, &player.InventorySlot{ItemID: hardeningBoltsID, Quantity: 7})
		p.Equipment[item.SlotAmmo] = hardeningArrowsID
		p.AmmoQty = 42

		h.g.doWear(sess, "test bolts")

		if got := p.Equipment[item.SlotAmmo]; got != hardeningArrowsID {
			t.Errorf("equipped ammo = %q, want %q: a refused swap must not clear equipment", got, hardeningArrowsID)
		}
		if p.AmmoQty != 42 {
			t.Errorf("AmmoQty = %d, want 42", p.AmmoQty)
		}
		bolts := p.InvSlot(3)
		if bolts == nil || bolts.ItemID != hardeningBoltsID || bolts.Quantity != 7 {
			t.Errorf("source stack changed by a refused swap: %+v", bolts)
		}
		if out := sess.Conn.(*chanConn).Bytes(); !strings.Contains(string(out), "inventory is full") {
			t.Errorf("expected a full-inventory message, got %q", out)
		}
	})
}

func TestUnequipAmmoSwapMovesStackToFreeSlot(t *testing.T) {
	h := newHarness(t)
	h.seedAccount("alice")
	p := h.seedCharacter("alice", "alice")
	seedAmmoItems(t, h)
	h.g.RunOnOwner(func() {
		h.g.ItemStore.Reload(h.dir)
		sess := fillAllSlots(p)
		p.SetInvSlot(0, nil)
		p.SetInvSlot(3, &player.InventorySlot{ItemID: hardeningBoltsID, Quantity: 7})
		p.Equipment[item.SlotAmmo] = hardeningArrowsID
		p.AmmoQty = 42

		h.g.doWear(sess, "test bolts")

		if got := p.Equipment[item.SlotAmmo]; got != hardeningBoltsID {
			t.Fatalf("equipped ammo = %q, want %q", got, hardeningBoltsID)
		}
		if p.AmmoQty != 7 {
			t.Errorf("AmmoQty = %d, want 7", p.AmmoQty)
		}
		stored := p.InvSlot(0)
		if stored == nil || stored.ItemID != hardeningArrowsID || stored.Quantity != 42 {
			t.Fatalf("unequipped arrows not stored in the free slot: %+v", stored)
		}
	})
}

func TestRemoveAllAmmoKeepsStackWhenInventoryFull(t *testing.T) {
	h := newHarness(t)
	h.seedAccount("alice")
	p := h.seedCharacter("alice", "alice")
	seedAmmoItems(t, h)
	h.g.RunOnOwner(func() {
		h.g.ItemStore.Reload(h.dir)
		sess := fillAllSlots(p)
		p.Equipment[item.SlotAmmo] = hardeningArrowsID
		p.AmmoQty = 42

		h.g.removeAllAmmo(sess, p, hardeningArrowsID)

		if got := p.Equipment[item.SlotAmmo]; got != hardeningArrowsID {
			t.Errorf("equipped ammo = %q, want %q", got, hardeningArrowsID)
		}
		if p.AmmoQty != 42 {
			t.Errorf("AmmoQty = %d, want 42", p.AmmoQty)
		}
		out := string(sess.Conn.(*chanConn).Bytes())
		if strings.Contains(out, "You remove") {
			t.Errorf("nothing was removed but the removal was reported: %q", out)
		}
		if !strings.Contains(out, "Nowhere to put that!") {
			t.Errorf("expected a failure message, got %q", out)
		}
	})
}

func TestRemoveAllKeepsAmmoWhenInventoryFull(t *testing.T) {
	h := newHarness(t)
	h.seedAccount("alice")
	p := h.seedCharacter("alice", "alice")
	seedAmmoItems(t, h)
	h.g.RunOnOwner(func() {
		h.g.ItemStore.Reload(h.dir)
		sess := fillAllSlots(p)
		p.Equipment[item.SlotAmmo] = hardeningArrowsID
		p.AmmoQty = 42

		h.g.doRemoveAll(sess)

		if got := p.Equipment[item.SlotAmmo]; got != hardeningArrowsID || p.AmmoQty != 42 {
			t.Errorf("remove all lost the equipped ammo: %q x%d", got, p.AmmoQty)
		}
		if got := p.CountItem(hardeningArrowsID); got != 0 {
			t.Errorf("remove all invented %d arrows", got)
		}
	})
}

func TestRemoveAllAmmoMovesStackToFreeSlot(t *testing.T) {
	h := newHarness(t)
	h.seedAccount("alice")
	p := h.seedCharacter("alice", "alice")
	seedAmmoItems(t, h)
	h.g.RunOnOwner(func() {
		h.g.ItemStore.Reload(h.dir)
		sess := fillAllSlots(p)
		p.SetInvSlot(0, nil)
		p.Equipment[item.SlotAmmo] = hardeningArrowsID
		p.AmmoQty = 42

		h.g.removeAllAmmo(sess, p, hardeningArrowsID)

		if _, ok := p.Equipment[item.SlotAmmo]; ok {
			t.Error("equipment entry survived a successful removal")
		}
		if p.AmmoQty != 0 {
			t.Errorf("AmmoQty = %d, want 0", p.AmmoQty)
		}
		stored := p.InvSlot(0)
		if stored == nil || stored.ItemID != hardeningArrowsID || stored.Quantity != 42 {
			t.Fatalf("removed arrows not stored in the free slot: %+v", stored)
		}
		if out := string(sess.Conn.(*chanConn).Bytes()); !strings.Contains(out, "You remove") {
			t.Errorf("removal not reported: %q", out)
		}
	})
}