package db

import (
	"testing"
)

// builtInTypeID returns the id of the named built-in device type.
func builtInTypeID(t *testing.T, s *Store, name string) int64 {
	t.Helper()
	all, _ := s.ListBuiltInDeviceTypes()
	for _, dt := range all {
		if dt.Name == name {
			return dt.ID
		}
	}
	t.Fatalf("built-in %q not found", name)
	return 0
}

// ------------------------------------------------------ basic solver wins

func TestSolve_BasicNAStoSwitch(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	nasT := builtInTypeID(t, s, "NAS")
	swT := builtInTypeID(t, s, "Switch")
	nas, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "NAS", TypeID: &nasT, X: 0, Y: 0, Width: 100, Height: 35})
	sw, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "Switch", TypeID: &swT, X: 200, Y: 0, Width: 100, Height: 35})
	rj45 := int64(5)
	_, _ = s.CreateConnectionRequirement(p.ID, ConnectionRequirementCreate{
		FromDeviceID: nas.ID, ToDeviceID: sw.ID, PreferredCableTypeID: &rj45,
	})
	res, err := s.Solve(p.ID, false)
	if err != nil {
		t.Fatalf("solve: %v", err)
	}
	if len(res.CablesAdded) != 1 {
		t.Fatalf("cables_added len = %d, want 1", len(res.CablesAdded))
	}
	if res.CablesAdded[0].TypeID != rj45 {
		t.Errorf("cable type = %d, want %d (RJ45)", res.CablesAdded[0].TypeID, rj45)
	}
	if !res.CablesAdded[0].Auto {
		t.Errorf("cable.auto should be true")
	}
	if len(res.Unsatisfied) != 0 {
		t.Errorf("unsatisfied should be empty; got %+v", res.Unsatisfied)
	}
}

func TestSolve_AmbiguousType_RequirementUnsatisfied(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	// Both PCs have Power + USB + HDMI + RJ45 → multiple types match.
	pcT := builtInTypeID(t, s, "PC")
	a, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "A", TypeID: &pcT, X: 0, Y: 0, Width: 100, Height: 35})
	b, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "B", TypeID: &pcT, X: 200, Y: 0, Width: 100, Height: 35})
	_, _ = s.CreateConnectionRequirement(p.ID, ConnectionRequirementCreate{
		FromDeviceID: a.ID, ToDeviceID: b.ID, // no PreferredCableTypeID
	})
	res, _ := s.Solve(p.ID, true)
	if len(res.CablesAdded) != 0 {
		t.Errorf("ambiguous: should not add cables, got %d", len(res.CablesAdded))
	}
	if len(res.Unsatisfied) != 1 || res.Unsatisfied[0].Reason == "" {
		t.Errorf("expected 1 unsatisfied req with non-empty reason; got %+v", res.Unsatisfied)
	}
}

func TestSolve_NoFreePort_RequirementUnsatisfied(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	// Mouse only has 1 USB port. Two USB requirements against it should
	// leave one unsatisfied.
	mouseT := builtInTypeID(t, s, "Mouse")
	pcT := builtInTypeID(t, s, "PC")
	mouse, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "Mouse", TypeID: &mouseT, X: 0, Y: 0, Width: 100, Height: 35})
	pc1, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "PC1", TypeID: &pcT, X: 200, Y: 0, Width: 100, Height: 35})
	pc2, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "PC2", TypeID: &pcT, X: 400, Y: 0, Width: 100, Height: 35})
	usb := int64(2)
	_, _ = s.CreateConnectionRequirement(p.ID, ConnectionRequirementCreate{
		FromDeviceID: mouse.ID, ToDeviceID: pc1.ID, PreferredCableTypeID: &usb,
	})
	_, _ = s.CreateConnectionRequirement(p.ID, ConnectionRequirementCreate{
		FromDeviceID: mouse.ID, ToDeviceID: pc2.ID, PreferredCableTypeID: &usb,
	})
	res, _ := s.Solve(p.ID, true)
	if len(res.CablesAdded) != 1 {
		t.Errorf("expected 1 cable to land (one mouse USB), got %d", len(res.CablesAdded))
	}
	if len(res.Unsatisfied) != 1 {
		t.Errorf("expected 1 unsatisfied; got %d (%+v)", len(res.Unsatisfied), res.Unsatisfied)
	}
}

// ----------------------------------------------- preview vs apply semantics

func TestSolve_PreviewDoesNotWrite(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	nasT := builtInTypeID(t, s, "NAS")
	swT := builtInTypeID(t, s, "Switch")
	nas, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "NAS", TypeID: &nasT, X: 0, Y: 0, Width: 100, Height: 35})
	sw, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "Switch", TypeID: &swT, X: 200, Y: 0, Width: 100, Height: 35})
	rj45 := int64(5)
	_, _ = s.CreateConnectionRequirement(p.ID, ConnectionRequirementCreate{
		FromDeviceID: nas.ID, ToDeviceID: sw.ID, PreferredCableTypeID: &rj45,
	})
	_, _ = s.Solve(p.ID, true) // preview
	cables, _ := s.ListCables(p.ID)
	if len(cables) != 0 {
		t.Errorf("preview wrote %d cables; want 0", len(cables))
	}
}

func TestSolve_ApplyThenIdempotent(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	nasT := builtInTypeID(t, s, "NAS")
	swT := builtInTypeID(t, s, "Switch")
	nas, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "NAS", TypeID: &nasT, X: 0, Y: 0, Width: 100, Height: 35})
	sw, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "Switch", TypeID: &swT, X: 200, Y: 0, Width: 100, Height: 35})
	rj45 := int64(5)
	_, _ = s.CreateConnectionRequirement(p.ID, ConnectionRequirementCreate{
		FromDeviceID: nas.ID, ToDeviceID: sw.ID, PreferredCableTypeID: &rj45,
	})
	r1, _ := s.Solve(p.ID, false)
	if len(r1.CablesAdded) != 1 {
		t.Fatalf("first apply: cables_added=%d, want 1", len(r1.CablesAdded))
	}
	r2, _ := s.Solve(p.ID, false)
	if len(r2.CablesAdded) != 0 {
		t.Errorf("second apply: cables_added=%d, want 0 (idempotent)", len(r2.CablesAdded))
	}
	if len(r2.CablesKept) != 1 {
		t.Errorf("second apply: cables_kept=%d, want 1", len(r2.CablesKept))
	}
}

func TestSolve_ManualCableReservesPort(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	mouseT := builtInTypeID(t, s, "Mouse")
	pcT := builtInTypeID(t, s, "PC")
	mouse, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "Mouse", TypeID: &mouseT, X: 0, Y: 0, Width: 100, Height: 35})
	pc, _ := s.CreateDevice(p.ID, DeviceCreate{Name: "PC", TypeID: &pcT, X: 200, Y: 0, Width: 100, Height: 35})

	// Manual cable USB Mouse↔PC: claims the only mouse USB port.
	ports, _ := s.ListPortsForProject(p.ID)
	var mouseUSB, pcUSB int64
	for _, prt := range ports {
		if prt.DeviceID == mouse.ID && prt.TypeID == 2 {
			mouseUSB = prt.ID
		}
		if prt.DeviceID == pc.ID && prt.TypeID == 2 {
			pcUSB = prt.ID
			break
		}
	}
	usb := int64(2)
	_, _ = s.CreateCable(p.ID, CableCreate{
		TypeID: usb,
		From:   CableEndpoint{PortID: &mouseUSB},
		To:     CableEndpoint{PortID: &pcUSB},
		Auto:   false,
	})

	// Now add a requirement that also wants USB on the mouse → no free port.
	_, _ = s.CreateConnectionRequirement(p.ID, ConnectionRequirementCreate{
		FromDeviceID: mouse.ID, ToDeviceID: pc.ID, PreferredCableTypeID: &usb,
	})
	res, _ := s.Solve(p.ID, true)
	if len(res.Unsatisfied) == 0 {
		t.Errorf("expected unsatisfied req (manual cable should reserve the only mouse USB port)")
	}
}

// -------------------------------------------------------- setup templates

func TestApplyTemplate_LivingRoom(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	tmpls, _ := s.ListSetupTemplates()
	var lr SetupTemplate
	for _, tm := range tmpls {
		if tm.Name == "Living Room" {
			lr = tm
			break
		}
	}
	if lr.ID == 0 {
		t.Fatal("Living Room template not seeded")
	}
	res, err := s.ApplyTemplate(p.ID, lr.ID, ApplyTemplateOptions{})
	if err != nil {
		t.Fatalf("apply: %v", err)
	}
	if len(res.DevicesAdded) != 3 {
		t.Errorf("devices added = %d, want 3 (TV, Soundbar, ChromeCast)", len(res.DevicesAdded))
	}
	if len(res.RequirementsAdded) != 2 {
		t.Errorf("requirements added = %d, want 2 (TV↔Soundbar, TV↔ChromeCast)", len(res.RequirementsAdded))
	}
	// Ports were seeded as part of the device creation.
	ports, _ := s.ListPortsForProject(p.ID)
	if len(ports) < 6 { // TV(3) + Soundbar(2) + ChromeCast(2) = 7
		t.Errorf("ports after template apply = %d, expected ≥6", len(ports))
	}
}

func TestApplyTemplate_HomeOffice_ThenSolve(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	tmpls, _ := s.ListSetupTemplates()
	var ho SetupTemplate
	for _, tm := range tmpls {
		if tm.Name == "Home Office" {
			ho = tm
			break
		}
	}
	if _, err := s.ApplyTemplate(p.ID, ho.ID, ApplyTemplateOptions{}); err != nil {
		t.Fatalf("apply: %v", err)
	}
	res, err := s.Solve(p.ID, false)
	if err != nil {
		t.Fatalf("solve: %v", err)
	}
	if len(res.CablesAdded) != 3 {
		t.Errorf("Home Office should solve to 3 cables (PC↔Screen, PC↔Keyboard, PC↔Mouse); got %d", len(res.CablesAdded))
	}
	if len(res.Unsatisfied) != 0 {
		t.Errorf("unsatisfied = %+v, want []", res.Unsatisfied)
	}
}

func TestApplyTemplate_NameCollisionSkipped(t *testing.T) {
	s := newTestStore(t)
	p, _ := s.CreateProject("LOFT", "", "")
	pcT := builtInTypeID(t, s, "PC")
	// Pre-create a device called "PC" so the Home Office template's PC collides.
	_, _ = s.CreateDevice(p.ID, DeviceCreate{Name: "PC", TypeID: &pcT, X: 0, Y: 0, Width: 100, Height: 35})

	tmpls, _ := s.ListSetupTemplates()
	var ho SetupTemplate
	for _, tm := range tmpls {
		if tm.Name == "Home Office" {
			ho = tm
			break
		}
	}
	res, _ := s.ApplyTemplate(p.ID, ho.ID, ApplyTemplateOptions{})
	if len(res.SkippedDevices) == 0 {
		t.Errorf("expected at least one skipped device for name collision; got %+v", res.SkippedDevices)
	}
	if len(res.RequirementsSkipped) == 0 {
		t.Errorf("PC requirements should be skipped when PC device skipped; got %+v", res.RequirementsSkipped)
	}
}