package apply

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

	"git.novox.be/novox/mesh-sdk/go/declaration"
	"github.com/novox/mesh-host/internal/store"
)

// R6-A AC3: given two modules declaring one path, when one module's want changes, the shared path is neither removed
// nor taken from the other module (novox/hq ADR 0539 §9).
func TestASharedPathIsNeitherRemovedNorTakenFromTheOtherModule(t *testing.T) {
	dir := t.TempDir()
	shared := filepath.Join(dir, "shared.conf")
	own := filepath.Join(dir, "a-own.conf")
	a := declare(t, `{"id":"a.shared","type":"file","path":"`+shared+`","content":"x\n","module":"a"},
	  {"id":"a.own","type":"file","path":"`+own+`","content":"a\n","module":"a"}`)
	b := declare(t, `{"id":"b.shared","type":"file","path":"`+shared+`","content":"x\n","module":"b"}`)

	state := store.State{}
	var err error
	_, state, err = ApplyModule(context.Background(), archHost(t), a, Scope{Module: "a", Others: b.Resources},
		state, store.OriginDeclared, noServices, nil, nil, nil, nil)
	if err != nil {
		t.Fatal(err)
	}
	_, state, err = ApplyModule(context.Background(), archHost(t), b, Scope{Module: "b", Others: a.Resources},
		state, store.OriginDeclared, noServices, nil, nil, nil, nil)
	if err != nil {
		t.Fatal(err)
	}

	// A's want changes: it no longer declares the shared path, and b still does.
	a2 := declare(t, `{"id":"a.own","type":"file","path":"`+own+`","content":"a\n","module":"a"}`)
	report, state, err := ApplyModule(context.Background(), archHost(t), a2, Scope{Module: "a", Others: b.Resources},
		state, store.OriginDeclared, noServices, nil, nil, nil, nil)
	if err != nil {
		t.Fatal(err)
	}
	if !exists(shared) {
		t.Fatal("the path another module still declares was removed")
	}
	if _, still := state.Find("b.shared"); !still {
		t.Fatal("the other module's record was taken away")
	}
	if _, still := state.Find("a.shared"); still {
		t.Fatal("the module's own record of the shared path was kept")
	}
	if o := outcomeOf(report, "a.shared"); o.Action != "forgotten" {
		t.Fatalf("the shared path: %+v", o)
	}
}

// R6-A AC4: given modules A and B on a node, when A's want is removed, only A's resources are removed and B is
// untouched.
func TestARemovedModuleTakesOnlyItsOwnResources(t *testing.T) {
	dir := t.TempDir()
	fa, fb := filepath.Join(dir, "a.conf"), filepath.Join(dir, "b.conf")
	d := declare(t, `{"id":"a.conf","type":"file","path":"`+fa+`","content":"a\n","module":"a"},
	  {"id":"b.conf","type":"file","path":"`+fb+`","content":"b\n","module":"b"}`)
	_, state, err := Apply(context.Background(), archHost(t), d, store.State{}, store.OriginDeclared, noServices, nil, nil)
	if err != nil {
		t.Fatal(err)
	}
	if rec, _ := state.Find("a.conf"); rec.Module != "a" {
		t.Fatalf("the owner was not recorded: %+v", rec)
	}

	gone := &declaration.Declaration{}
	b := declare(t, `{"id":"b.conf","type":"file","path":"`+fb+`","content":"b\n","module":"b"}`)
	report, state, err := ApplyModule(context.Background(), archHost(t), gone, Scope{Module: "a", Others: b.Resources},
		state, store.OriginDeclared, noServices, nil, nil, nil, nil)
	if err != nil {
		t.Fatal(err)
	}
	if exists(fa) || !exists(fb) {
		t.Fatalf("a's file exists %v, b's file exists %v", exists(fa), exists(fb))
	}
	if o := outcomeOf(report, "a.conf"); o.Action != "removed" {
		t.Fatalf("a's file: %+v", o)
	}
	if _, still := state.Find("b.conf"); !still {
		t.Fatal("b's record was removed")
	}
	if _, still := state.Find("a.conf"); still {
		t.Fatal("a's record is still there")
	}
}

// A record from before the owner was kept is read by its id, so the first removal after the switch is the module's too.
func TestARecordWithoutAnOwnerBelongsToTheModuleItsIdNames(t *testing.T) {
	dir := t.TempDir()
	fa, fb := filepath.Join(dir, "a.conf"), filepath.Join(dir, "b.conf")
	d := declare(t, `{"id":"a.conf","type":"file","path":"`+fa+`","content":"a\n"},
	  {"id":"b.conf","type":"file","path":"`+fb+`","content":"b\n"}`)
	_, state, err := Apply(context.Background(), archHost(t), d, store.State{}, store.OriginDeclared, noServices, nil, nil)
	if err != nil {
		t.Fatal(err)
	}
	for i := range state.Resources {
		state.Resources[i].Module = ""
	}
	_, state, err = ApplyModule(context.Background(), archHost(t), &declaration.Declaration{}, Scope{Module: "a"},
		state, store.OriginDeclared, noServices, nil, nil, nil, nil)
	if err != nil {
		t.Fatal(err)
	}
	if exists(fa) || !exists(fb) {
		t.Fatalf("a's file exists %v, b's file exists %v", exists(fa), exists(fb))
	}
}

// A resource that leaves the node's own composition for its module's own is that module's now: the node's own apply
// leaves it as it is, whatever its type, until the module's own apply takes it (issue 1945, live on 2026-10-25 at 02:32:
// shanks and g14 lost systemd-resolved's guard, its resolver files and sudo's operator file, ace qbittorrent's server,
// because the node's own apply removed every record no longer in it, the others holding the very same resources or not).
//
// And a resource the node's own composition carried for a module a want still places here (a folded module of the old
// form, held) is never removed by the node's own apply when a composition leaves it out: the apply is refused whole and
// says why (issue 774, live on 2026-10-29 at 07:54 UTC on the bus node: the node's own composition, composed without what
// it ran once the kept declaration was read no more, removed the bus server, the proxy and three held modules). Only its
// want's removal lets it go.
func TestAResourceThatMovedToItsModulesCompositionIsLeftByTheNodesOwnApply(t *testing.T) {
	for _, tc := range []struct {
		name    string
		id      string // the resource the node's own composition carried, and no longer does
		moved   bool   // its module's own composition now declares it (Others)
		placed  bool   // a want still places its module here
		refused bool   // the node's own apply is refused whole
		stays   bool   // the resource is still on the machine and recorded
		// wants names the modules whose want says removed (Scope.RemovedByWant); nil leaves the guard to Placed alone.
		wants []string
	}{
		{name: "moved to its module's own composition", id: "systemd-resolved.fact-suffix", moved: true, placed: true, stays: true},
		{name: "a held folded module, in no composition", id: "nats.server-conf", placed: true, refused: true, stays: true},
		{name: "its module's want removed", id: "nats.server-conf"},
		// Issue 774, review of the re-land, round 1: a module folded in the node's own has no want, so Placed does not name
		// it; in the node's own apply only a module a want removed loses its resources.
		{name: "a folded module with no want", id: "nats.server-conf", wants: []string{}, refused: true, stays: true},
		{name: "a folded module a want removed", id: "nats.server-conf", wants: []string{"nats", "old"}},
	} {
		t.Run(tc.name, func(t *testing.T) {
			dir := t.TempDir()
			fact := filepath.Join(dir, "carried")
			gone := filepath.Join(dir, "gone.conf")
			own := declare(t, `{"id":"`+tc.id+`","type":"file","path":"`+fact+`","content":"mesh\n"},
			  {"id":"old.gone","type":"file","path":"`+gone+`","content":"g\n"}`)
			_, state, err := ApplyModule(context.Background(), archHost(t), own, Scope{Module: store.NodeModule},
				state0(), store.OriginDeclared, noServices, nil, nil, nil, nil)
			if err != nil {
				t.Fatal(err)
			}
			module, _ := declaration.ModuleGuess(tc.id)
			scope := Scope{Module: store.NodeModule}
			if tc.moved {
				moved := declare(t, `{"id":"`+tc.id+`","type":"file","path":"`+fact+`","content":"mesh\n","module":"`+module+`"}`)
				scope.Others = moved.Resources
			}
			if tc.placed {
				scope.Placed = map[string]bool{module: true}
			}
			if tc.wants != nil {
				scope.RemovedByWant = map[string]bool{}
				for _, m := range tc.wants {
					scope.RemovedByWant[m] = true
				}
			}
			report, after, err := ApplyModule(context.Background(), archHost(t), &declaration.Declaration{}, scope, state,
				store.OriginDeclared, noServices, nil, nil, nil, nil)
			if tc.refused != (err != nil) {
				t.Fatalf("refused %v, want %v: %v", err != nil, tc.refused, err)
			}
			if tc.refused {
				if !strings.Contains(err.Error(), tc.id+" of "+module) {
					t.Fatalf("the refusal does not name what it kept: %v", err)
				}
				after = state
			}
			if exists(fact) != tc.stays {
				t.Fatalf("the carried resource exists %v, want %v: %+v", exists(fact), tc.stays, outcomeOf(report, tc.id))
			}
			if _, still := after.Find(tc.id); still != tc.stays {
				t.Fatalf("the carried resource's record kept %v, want %v", still, tc.stays)
			}
			if exists(gone) == !tc.refused {
				t.Fatalf("a resource no composition holds any more exists %v, with the apply refused %v", exists(gone), tc.refused)
			}
		})
	}
}

func state0() store.State { return store.State{} }