package stacks

import (
	"context"
	"go/ast"
	"go/parser"
	"go/token"
	"io"
	"log"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"gitea.dooplex.hu/admin/felhom-controller/internal/config"
	"gopkg.in/yaml.v3"
)

// Slice 3 (v0.235.0) — the pin, the stored definition, and adoption.

const pinTplOld = "services:\n  web:\n    image: nextcloud:31.0.14-apache\n"
const pinTplNew = "services:\n  web:\n    image: nextcloud:34.0.1-apache\n"

// newPinManager builds a Manager with one deployed stack and a catalog cache.
func newPinManager(t *testing.T, liveCompose, catalogCompose, appYAML string) (*Manager, string) {
	t.Helper()
	root := t.TempDir()
	cfg := &config.Config{}
	cfg.Paths.StacksDir = filepath.Join(root, "stacks")
	cfg.Paths.DataDir = filepath.Join(root, "data")
	stackDir := filepath.Join(cfg.Paths.StacksDir, "nextcloud")
	catDir := filepath.Join(cfg.Paths.DataDir, "catalog-cache", "templates", "nextcloud")
	for _, d := range []string{stackDir, catDir} {
		if err := os.MkdirAll(d, 0o755); err != nil {
			t.Fatal(err)
		}
	}
	mustWrite(t, filepath.Join(stackDir, "docker-compose.yml"), liveCompose)
	if catalogCompose != "" {
		mustWrite(t, filepath.Join(catDir, "docker-compose.yml"), catalogCompose)
	}
	mustWrite(t, filepath.Join(stackDir, "app.yaml"), appYAML)

	m := &Manager{
		cfg: cfg, logger: log.New(io.Discard, "", 0), composeCmd: "docker compose",
		encKey: []byte("0123456789abcdef0123456789abcdef"),
		stacks: map[string]*Stack{},
	}
	m.stacks["nextcloud"] = &Stack{
		Name: "nextcloud", Deployed: true,
		ComposePath: filepath.Join(stackDir, "docker-compose.yml"),
		AppConfig:   LoadAppConfig(stackDir),
	}
	return m, stackDir
}

func mustWrite(t *testing.T, path, body string) {
	t.Helper()
	if err := os.WriteFile(path, []byte(body), 0o644); err != nil {
		t.Fatal(err)
	}
}

func readPin(t *testing.T, dir string) *AppConfig {
	t.Helper()
	b, err := os.ReadFile(filepath.Join(dir, "app.yaml"))
	if err != nil {
		t.Fatal(err)
	}
	cfg := &AppConfig{}
	if err := yaml.Unmarshal(b, cfg); err != nil {
		t.Fatal(err)
	}
	return cfg
}

// --- GROUP D: the Update button advances the pin, BEFORE the pull ---

// TestGroupD_UpdateAdvancesThePinAndRendersTheNewDefinition.
//
// The ordering is the assertion that matters: `compose pull` and `up -d` act on the file on disk, so
// the catalog's definition has to BE that file before either runs. A pin set afterwards would pull
// the frozen version and report success — a button that lies.
func TestGroupD_UpdateAdvancesThePinAndRendersTheNewDefinition(t *testing.T) {
	m, stackDir := newPinManager(t, pinTplOld, pinTplNew,
		"deployed: true\nenv: {}\npinned_images:\n    web: nextcloud:31.0.14-apache\n")
	mustWrite(t, AppliedComposePath(stackDir), pinTplOld)

	if err := m.advancePinToCatalog("nextcloud", stackDir); err != nil {
		t.Fatal(err)
	}
	if got := readPin(t, stackDir).PinnedImages["web"]; got != "nextcloud:34.0.1-apache" {
		t.Fatalf("pin = %q, want the catalog's current ref", got)
	}
	live, _ := os.ReadFile(filepath.Join(stackDir, "docker-compose.yml"))
	if !strings.Contains(string(live), "34.0.1-apache") {
		t.Fatalf("the LIVE compose file must carry the new definition BEFORE the pull:\n%s", live)
	}
	applied, _ := os.ReadFile(AppliedComposePath(stackDir))
	if !strings.Contains(string(applied), "34.0.1-apache") {
		t.Fatalf("the new definition must be stored as the applied one:\n%s", applied)
	}
}

// TestGroupD_UpdateRefusesWhenTheCatalogCannotBeRead — a no-op reported as success is worse than a
// refusal. An UNPINNED app is untouched and returns nil: that is pre-v0.235.0 behaviour.
func TestGroupD_UpdateRefusesWhenTheCatalogCannotBeRead(t *testing.T) {
	m, stackDir := newPinManager(t, pinTplOld, "", // no catalog template at all
		"deployed: true\nenv: {}\npinned_images:\n    web: nextcloud:31.0.14-apache\n")
	err := m.advancePinToCatalog("nextcloud", stackDir)
	if err == nil {
		t.Fatal("a pinned app whose catalog definition cannot be read must REFUSE, not silently no-op")
	}
	if !strings.Contains(err.Error(), "catalog") {
		t.Errorf("the refusal must name the cause, got: %v", err)
	}

	m2, dir2 := newPinManager(t, pinTplOld, "", "deployed: true\nenv: {}\n") // unpinned
	if err := m2.advancePinToCatalog("nextcloud", dir2); err != nil {
		t.Fatalf("an UNPINNED app must be left alone and succeed: %v", err)
	}
}

// --- GROUP E: adoption never guesses ---

// TestGroupE_AdoptionSkipsWhatItCannotPinConfidently.
//
// COMPANION RED-PROOF 2 (run 2026-09-06): delete the observationCoversTemplate guard from AdoptPins
// so it pins from whatever it observed. The "incomplete observation" sub-test then fails with a pin
// written from a partial reading. Reverted.
func TestGroupE_AdoptionSkipsWhatItCannotPinConfidently(t *testing.T) {
	twoSvc := "services:\n  web:\n    image: nextcloud:31.0.14-apache\n  db:\n    image: postgres:16-alpine\n"

	t.Run("incomplete observation", func(t *testing.T) {
		m, stackDir := newPinManager(t, twoSvc, twoSvc, `deployed: true
env: {}
installed_images:
    web:
        ref: nextcloud:31.0.14-apache
        digest: sha256:a
        at: "2026-09-01T00:00:00Z"
`)
		m.stacks["nextcloud"].AppConfig = LoadAppConfig(stackDir)
		if n := m.AdoptPins(); n != 0 {
			t.Fatalf("pinned %d, want 0 — only 1 of 2 services was observed", n)
		}
		if got := readPin(t, stackDir).PinnedImages; len(got) != 0 {
			t.Fatalf("no pin may be synthesised from a partial observation, got %+v", got)
		}
	})

	t.Run("complete but running something the template no longer offers", func(t *testing.T) {
		m, stackDir := newPinManager(t, pinTplNew, pinTplNew, `deployed: true
env: {}
installed_images:
    web:
        ref: nextcloud:31.0.14-apache
        digest: sha256:a
        at: "2026-09-01T00:00:00Z"
`)
		m.stacks["nextcloud"].AppConfig = LoadAppConfig(stackDir)
		if n := m.AdoptPins(); n != 0 {
			t.Fatalf("pinned %d, want 0 — we have no stored definition for what it runs", n)
		}
		if got := readPin(t, stackDir).PinnedImages; len(got) != 0 {
			t.Fatalf("no pin may be invented here, got %+v", got)
		}
		if _, err := os.Stat(AppliedComposePath(stackDir)); err == nil {
			t.Fatal("no applied definition may be manufactured by substituting refs into a newer template")
		}
	})

	t.Run("complete and matching — pinned, with the definition stored", func(t *testing.T) {
		m, stackDir := newPinManager(t, pinTplOld, pinTplOld, `deployed: true
env: {}
installed_images:
    web:
        ref: nextcloud:31.0.14-apache
        digest: sha256:a
        at: "2026-09-01T00:00:00Z"
`)
		m.stacks["nextcloud"].AppConfig = LoadAppConfig(stackDir)
		if n := m.AdoptPins(); n != 1 {
			t.Fatalf("pinned %d, want 1", n)
		}
		if got := readPin(t, stackDir).PinnedImages["web"]; got != "nextcloud:31.0.14-apache" {
			t.Fatalf("pin = %q", got)
		}
		stored, err := LoadAppliedDefinition(stackDir)
		if err != nil || !strings.Contains(string(stored), "31.0.14-apache") {
			t.Fatalf("the running definition must be stored: %v %s", err, stored)
		}
		// Idempotent: a second pass must not re-pin.
		if n := m.AdoptPins(); n != 0 {
			t.Errorf("a second adoption pass pinned %d, want 0", n)
		}
	})
}

// TestGroupE_AdoptionTouchesNoContainer — it reads and writes files only.
func TestGroupE_AdoptionTouchesNoContainer(t *testing.T) {
	m, stackDir := newPinManager(t, pinTplOld, pinTplOld, `deployed: true
env: {}
installed_images:
    web:
        ref: nextcloud:31.0.14-apache
        digest: sha256:a
        at: "2026-09-01T00:00:00Z"
`)
	m.stacks["nextcloud"].AppConfig = LoadAppConfig(stackDir)
	m.installedExecFn = func(context.Context, string, []string, string, ...string) (string, error) {
		t.Fatal("adoption must not run any docker command")
		return "", nil
	}
	m.execFn = func(string, ...string) (string, error) {
		t.Fatal("adoption must not run any docker command")
		return "", nil
	}
	m.AdoptPins()
}

// --- GROUP F: a restore's pin survives, and RenderPlanFor reports it ---

// TestGroupF_RestorePinIsReportedToTheSyncer is the unit half of R-441. The live half is the
// measurement in the report; this pins the contract the syncer relies on.
func TestGroupF_RestorePinIsReportedToTheSyncer(t *testing.T) {
	m, stackDir := newPinManager(t, pinTplOld, pinTplNew, "deployed: true\nenv: {}\n")

	// What RecreateStackDefinitionFromUnit does: the unit's compose is already in the stack dir.
	pin, data, err := PinFromCompose(ComposePathIn(stackDir))
	if err != nil {
		t.Fatal(err)
	}
	if err := m.SetPin("nextcloud", stackDir, pin, data); err != nil {
		t.Fatal(err)
	}

	plan := m.RenderPlanFor("nextcloud")
	if !plan.Deployed || len(plan.Pinned) == 0 {
		t.Fatalf("the syncer must be told the app is deployed and pinned: %+v", plan)
	}
	if plan.Pinned["web"] != "nextcloud:31.0.14-apache" {
		t.Errorf("pin = %q, want the unit's captured image", plan.Pinned["web"])
	}
	if plan.AppliedPath == "" {
		t.Fatal("the stored definition must be reported, or the syncer cannot freeze and the catalog wins in 15 minutes (R-441)")
	}
}

// TestSetPin_EmptyPinAndMissingAppYAMLAreRefusedOrNoOps.
func TestSetPin_EmptyPinAndMissingAppYAMLAreRefusedOrNoOps(t *testing.T) {
	m, stackDir := newPinManager(t, pinTplOld, pinTplOld, "deployed: true\nenv: {}\n")
	if err := m.SetPin("nextcloud", stackDir, map[string]string{}, []byte(pinTplOld)); err == nil {
		t.Error("an empty pin must be refused — it would read as UNPINNED and silently unfreeze the app")
	}
	if err := StoreAppliedDefinition(stackDir, nil); err == nil {
		t.Error("an empty applied definition must be refused")
	}
}

// TestSetPin_UnchangedPinDoesNotRewriteAppYAML — app.yaml holds encrypted secrets.
func TestSetPin_UnchangedPinDoesNotRewriteAppYAML(t *testing.T) {
	m, stackDir := newPinManager(t, pinTplOld, pinTplOld,
		"deployed: true\nenv: {}\npinned_images:\n    web: nextcloud:31.0.14-apache\n")
	p := filepath.Join(stackDir, "app.yaml")
	st0, _ := os.Stat(p)
	if err := m.SetPin("nextcloud", stackDir, map[string]string{"web": "nextcloud:31.0.14-apache"}, []byte(pinTplOld)); err != nil {
		t.Fatal(err)
	}
	st1, _ := os.Stat(p)
	if !st0.ModTime().Equal(st1.ModTime()) || st0.Size() != st1.Size() {
		t.Error("an unchanged pin must not rewrite app.yaml")
	}
}

// --- GROUP H: the wiring ---

// TestGroupH_RenderSeamAndAdoptionAreWiredAtStartup.
//
// The render is INERT unless main.go passes the function, and adoption is inert unless it is called.
// An AST walk, NOT a strings.Contains: a commented-out call still contains the string, which is the
// exact shape of the seam-built-but-never-wired class this project has shipped four times.
//
// It also asserts the ORDER, which is load-bearing: syncer.Start() fires an immediate sync, and if
// that runs before adoption every app is still unpinned, so the first sync of every boot would copy
// the catalog verbatim over a deployed app — the behaviour this release removes, once per boot.
func TestGroupH_RenderSeamAndAdoptionAreWiredAtStartup(t *testing.T) {
	src := filepath.Join("..", "..", "cmd", "controller", "main.go")
	fset := token.NewFileSet()
	f, err := parser.ParseFile(fset, src, nil, 0)
	if err != nil {
		t.Skipf("cmd/controller is gitignored in some checkouts: %v", err)
	}
	var seamLine, adoptLine, startLine, backfillLine int
	ast.Inspect(f, func(n ast.Node) bool {
		call, ok := n.(*ast.CallExpr)
		if !ok {
			return true
		}
		sel, ok := call.Fun.(*ast.SelectorExpr)
		if !ok {
			return true
		}
		line := fset.Position(call.Pos()).Line
		switch sel.Sel.Name {
		case "SetRenderPlanFn":
			seamLine = line
		case "AdoptPins":
			adoptLine = line
		case "BackfillInstalledImages":
			backfillLine = line
		case "Start":
			if id, ok := sel.X.(*ast.Ident); ok && id.Name == "syncer" {
				startLine = line
			}
		}
		return true
	})
	if seamLine == 0 {
		t.Fatal("SetRenderPlanFn is never called from cmd/controller — the render is INERT and the syncer copies verbatim")
	}
	if adoptLine == 0 {
		t.Fatal("AdoptPins is never called from cmd/controller — nothing would ever be pinned")
	}
	if backfillLine != 0 && adoptLine < backfillLine {
		t.Errorf("adoption (line %d) must run AFTER the installed-images backfill (line %d) — it needs that observation", adoptLine, backfillLine)
	}
	if startLine == 0 {
		t.Fatal("syncer.Start() is never called")
	}
	if startLine < adoptLine {
		t.Errorf("syncer.Start() (line %d) must come AFTER AdoptPins (line %d): the initial sync would otherwise run while every app is unpinned and overwrite a deployed app's version once per boot", startLine, adoptLine)
	}
}