package api

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"

	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
	"gitea.dooplex.hu/admin/felhom-controller/internal/stacks"
)

// R-609 (v0.261.0) — the 409 carries a machine-readable REASON, additively.
//
// WHY. `UpdateRefusal.Reason` has existed since v0.237.0 and never left the process: the body carried
// only the translated sentence. A caller that is not a person cannot parse a Hungarian sentence, and
// the distinction it needs is not decorative:
//
//	TRANSIENT — busy, updating, deploying, migrating, self_updating → try again later
//	TERMINAL  — held, downgrade                                     → never press this again
//
// An unattended caller that cannot tell them apart either gives up on a passing backup window, or
// presses a terminally-refused button on every pass for ever. `09` §6.2's caller reads exactly this.
//
// The SENTENCE is unchanged and stays where it was, so no page moves — this is purely additive.

// reasonOf pulls `data.reason` out of a refusal body, or "" when absent.
func reasonOf(t *testing.T, resp apiResponse) string {
	t.Helper()
	if resp.Data == nil {
		return ""
	}
	m, ok := resp.Data.(map[string]interface{})
	if !ok {
		t.Fatalf("data is not an object: %#v", resp.Data)
	}
	s, _ := m["reason"].(string)
	return s
}

// TestR609_EveryRefusalCarriesItsReason is table-driven over the refusal paths reachable without
// docker, and it INCLUDES the router's own hold line — which fires before UpdatePreflight and was
// the one that had no reason at all until this test was written.
//
// COMPANION RED-PROOF (run 2026-09-21): drop the `Data:` field from either writeJSON in actionStack's
// update paths. The corresponding row fails with `reason = ""`. Reverted.
func TestR609_EveryRefusalCarriesItsReason(t *testing.T) {
	cases := []struct {
		name       string
		arrange    func(t *testing.T, r *Router, sett *settings.Settings, g *apiFakeGuards, dir string)
		wantReason string
		wantCode   int
	}{
		{
			name: "held — the ROUTER's own line, before the preflight",
			arrange: func(t *testing.T, r *Router, sett *settings.Settings, g *apiFakeGuards, dir string) {
				if err := sett.SetRestoreHold(settings.RestoreHold{
					Stack: "app", At: "2026-09-21T08:00:00Z",
					Reason: settings.HoldReasonUpdateFailed, CopyDate: "2026-09-21T01:30:00Z",
				}); err != nil {
					t.Fatal(err)
				}
			},
			wantReason: "held", wantCode: http.StatusConflict,
		},
		{
			name: "no_backup — nothing on any tier and none can be taken",
			arrange: func(_ *testing.T, _ *Router, _ *settings.Settings, g *apiFakeGuards, _ string) {
				g.points, g.cannotBackUp = nil, true
			},
			wantReason: "no_backup", wantCode: http.StatusConflict,
		},
		{
			name: "self_updating — the controller is swapping itself (v0.261.0)",
			arrange: func(_ *testing.T, r *Router, _ *settings.Settings, _ *apiFakeGuards, _ string) {
				r.stackMgr.SetSelfUpdatingCheck(func() bool { return true })
			},
			wantReason: "self_updating", wantCode: http.StatusConflict,
		},
		{
			name: "downgrade — the box runs something newer than the catalog (R-524)",
			arrange: func(t *testing.T, r *Router, _ *settings.Settings, _ *apiFakeGuards, dir string) {
				setInstalledAndCatalog(t, r, dir, "nginx:1.28", "nginx:1.27")
			},
			wantReason: "downgrade", wantCode: http.StatusConflict,
		},
		{
			name: "not_found — an app that exists nowhere",
			arrange: func(_ *testing.T, _ *Router, _ *settings.Settings, _ *apiFakeGuards, _ string) {},
			wantReason: "not_found", wantCode: http.StatusNotFound,
		},
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			r, sett, g, dir := newSlice4Router(t)
			c.arrange(t, r, sett, g, dir)

			name := "app"
			if c.wantReason == "not_found" {
				name = "no-such-app"
			}
			code, resp := postUpdateNamed(t, r, name)

			if code != c.wantCode {
				t.Errorf("code = %d, want %d (error %q)", code, c.wantCode, resp.Error)
			}
			if resp.OK {
				t.Fatal("a refusal must not answer ok")
			}
			if got := reasonOf(t, resp); got != c.wantReason {
				t.Errorf("reason = %q, want %q", got, c.wantReason)
			}
			// The sentence is the household's and must still be there, in words — never a bare key.
			if resp.Error == "" {
				t.Error("the reason is ADDITIVE: the sentence must still be present")
			}
		})
	}
}

// TestR609_ASuccessfulActionCarriesNoReason — the field is for refusals only, so a caller cannot
// mistake a normal answer for one.
func TestR609_ASuccessfulActionCarriesNoReason(t *testing.T) {
	r, _, _, _ := newSlice4Router(t)
	_, resp := postStopNamed(t, r, "app")
	if got := reasonOf(t, resp); got != "" {
		t.Errorf("a non-refusal must carry no reason, got %q", got)
	}
}

// ── helpers ─────────────────────────────────────────────────────────────────────────────────────

// postUpdateNamed is postUpdate for an arbitrary app name (the not_found row needs one that is absent).
func postUpdateNamed(t *testing.T, r *Router, name string) (int, apiResponse) {
	t.Helper()
	w := httptest.NewRecorder()
	r.actionStack(w, httptest.NewRequest("POST", "/api/stacks/x/action", nil), "update", name)
	var resp apiResponse
	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
		t.Fatalf("non-JSON body %q: %v", w.Body.String(), err)
	}
	return w.Code, resp
}

// postStopNamed exercises a NON-update action, as the control that `reason` is refusal-only.
func postStopNamed(t *testing.T, r *Router, name string) (int, apiResponse) {
	t.Helper()
	w := httptest.NewRecorder()
	r.actionStack(w, httptest.NewRequest("POST", "/api/stacks/x/action", nil), "stop", name)
	var resp apiResponse
	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
		t.Fatalf("non-JSON body %q: %v", w.Body.String(), err)
	}
	return w.Code, resp
}

// setInstalledAndCatalog puts the app AHEAD of the catalog, which is R-524's Ahead arm.
//
// It writes the REAL files the real code reads — `installed_images` into the app's app.yaml and a
// catalog template under <DataDir>/catalog-cache/templates/<app>/ — and then rescans. **No test-only
// seam is added to production code for this**: the whole point of the api tests here is that they go
// through the production handler over a real stacks.Manager, and a setter that only tests call would
// be a second way to reach the state, which is how the two drift apart.
func setInstalledAndCatalog(t *testing.T, r *Router, dir, installed, catalog string) {
	t.Helper()
	appYAML := slice4AppYAML + "installed_images:\n    app:\n        ref: " + installed +
		"\n        digest: sha256:x\n        at: \"2026-09-01T00:00:00Z\"\n"
	if err := os.WriteFile(filepath.Join(dir, "app.yaml"), []byte(appYAML), 0o600); err != nil {
		t.Fatal(err)
	}
	catDir := filepath.Join(r.cfg.Paths.DataDir, "catalog-cache", "templates", "app")
	if err := os.MkdirAll(catDir, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(catDir, "docker-compose.yml"),
		[]byte("services:\n  app:\n    image: "+catalog+"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := r.stackMgr.ScanStacks(); err != nil {
		t.Fatal(err)
	}
	// Positive control: the state this helper claims to create must actually exist, or the row it
	// serves would pass for the wrong reason (a different refusal firing first).
	if got := stacks.CatalogOrder(mustStack(t, r, "app")); got != stacks.UpdateOrderAhead {
		t.Fatalf("fixture did not produce the AHEAD state; CatalogOrder = %v", got)
	}
}

func mustStack(t *testing.T, r *Router, name string) stacks.Stack {
	t.Helper()
	st, ok := r.stackMgr.GetStack(name)
	if !ok {
		t.Fatalf("stack %q missing", name)
	}
	return *st
}