package testbus

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

	"encoding/json"

	"github.com/novox/mesh-controller/internal/beside"
)

// **The bus the tests run is the bus the mesh runs** (novox/hq ADR 0227 rule 9, to-be 45 §9). The server
// linked into the tests is held to the release the catalogue's bus image is — the catalogue a merge check
// clones beside this one, or the copy captured in testdata/beside (internal/beside, novox/hq issue 432) —
// and, in a merge check that has the facts snapshot, to the release the mesh's bus server says it runs. A
// bus upgrade moves the catalogue's pin; this then fails in the merge check until the tests' pin moves
// with it, so the controller is never tested against a bus the mesh no longer runs, or not yet.
func TestTheBusTheTestsRunIsTheBusTheMeshRuns(t *testing.T) {
	dockerfile := filepath.Join(beside.Catalogue(t), "nats", "Dockerfile")
	raw, err := os.ReadFile(dockerfile)
	if err != nil {
		t.Fatal(err)
	}
	pinned := regexp.MustCompile(`upstream: nats ([0-9.]+)-alpine`).FindSubmatch(raw)
	if pinned == nil {
		t.Fatalf("%s says no release its digest is", dockerfile)
	}
	if string(pinned[1]) != Version {
		t.Errorf("the tests run bus %s and the catalogue's bus image is %s: move go.mod's nats-server pin "+
			"(and `go mod vendor`) with the image", Version, pinned[1])
	}
	path := os.Getenv("MESH_FACTS")
	if path == "" {
		t.Logf("no MESH_FACTS: the bus the mesh runs is compared in a merge check, which has it")
		return
	}
	body, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	// Read as little of the snapshot as this needs (internal/facts holds the whole shape).
	var f struct {
		Taken    string `json:"taken"`
		Versions struct {
			Bus string `json:"bus"`
		} `json:"versions"`
	}
	if err := json.Unmarshal(body, &f); err != nil {
		t.Fatal(err)
	}
	if f.Versions.Bus != "" && strings.TrimPrefix(f.Versions.Bus, "v") != Version {
		t.Errorf("the tests run bus %s and the mesh's bus runs %s (facts of %s)", Version, f.Versions.Bus, f.Taken)
	}
}

// A test's bus is its own: what one test makes, the next never sees.