package manifest

import (
	"bytes"
	"encoding/json"
	"io/fs"
	"os"
	"path/filepath"
	"reflect"
	"slices"
	"strings"
	"testing"
)

// The controller's manifest reader is mesh-controller internal/catalogue (Manifest, manifest.go: Consumes :521,
// Invokes :590, Streams :613, Reads :659; StreamDeclaration, streams.go), an internal package of another repository.
// These tests decode the manifest strictly into the fields those types name (DisallowUnknownFields) and hold the
// rules of issue 1240 (ADR 0437 §4). The merge gate's module check proves the controller takes the manifest.

type state struct {
	Name    string `json:"name"`
	History int    `json:"history,omitempty"`
}

type artifact struct {
	Name     string `json:"name"`
	Kind     string `json:"kind"`
	Language string `json:"language"`
	System   string `json:"system"`
	From     string `json:"from"`
	Binary   string `json:"binary"`
}

type manifest struct {
	Module       string            `json:"module"`
	Version      string            `json:"version"`
	Slug         string            `json:"slug"`
	Uses         []string          `json:"uses"`
	State        []state           `json:"state"`
	Reads        []string          `json:"reads"`
	OwnSecrets   map[string]string `json:"own-secrets"`
	SecretsOwner string            `json:"secrets-owner"`
	Resources    []map[string]any  `json:"resources"`
	Build        struct {
		Artifacts []artifact `json:"artifacts"`
	} `json:"build"`
}

func load(t *testing.T) (manifest, map[string]json.RawMessage) {
	t.Helper()
	raw, err := os.ReadFile("module.json")
	if err != nil {
		t.Fatal(err)
	}
	var m manifest
	dec := json.NewDecoder(bytes.NewReader(raw))
	dec.DisallowUnknownFields()
	if err := dec.Decode(&m); err != nil {
		t.Fatalf("the controller's reader refuses a key this manifest has: %v", err)
	}
	var top map[string]json.RawMessage
	if err := json.Unmarshal(raw, &top); err != nil {
		t.Fatal(err)
	}
	return m, top
}

func sorted(s []string) []string {
	s = slices.Clone(s)
	slices.Sort(s)
	return s
}

func TestManifestDeclarations(t *testing.T) { // 1240/AC1
	m, top := load(t)
	if m.Module != "mesh-delivery-teller" {
		t.Errorf("module = %q", m.Module)
	}
	if want := []state{{Name: "answers", History: 5}}; !reflect.DeepEqual(m.State, want) {
		t.Errorf("state = %+v, want %+v", m.State, want)
	}
	if want := []string{"mesh-delivery-gate.asks"}; !reflect.DeepEqual(sorted(m.Reads), want) {
		t.Errorf("reads = %v, want %v", m.Reads, want)
	}
	if want := []string{"operator-channel"}; !reflect.DeepEqual(sorted(m.Uses), want) {
		t.Errorf("uses = %v, want %v", m.Uses, want)
	}
	if b, ok := m.OwnSecrets["broker"]; !ok || len(m.OwnSecrets) != 1 || b != "${dir:state}/broker" {
		t.Errorf("own-secrets = %v, want exactly broker", m.OwnSecrets)
	}
	if m.SecretsOwner != "mesh-delivery-teller" {
		t.Errorf("secrets-owner = %q", m.SecretsOwner)
	}
	// No consumes, invokes, emits, streams, bus, seat or tool (ADR 0437 §4).
	for _, k := range []string{"consumes", "invokes", "streams", "logs", "emits", "claims", "provides", "requires", "defines-seats", "tools", "seat", "seats", "bus"} {
		if _, ok := top[k]; ok {
			t.Errorf("the manifest declares %q: the teller has none", k)
		}
	}
}

func TestManifestProcess(t *testing.T) { // 1240/AC1
	m, _ := load(t)
	var procs []map[string]any
	for _, r := range m.Resources {
		if r["type"] == "process" {
			procs = append(procs, r)
		}
		if r["type"] == "tool" || r["type"] == "seat" {
			t.Errorf("resource %v: the teller serves no tool and holds no seat", r)
		}
	}
	if len(procs) != 1 {
		t.Fatalf("%d process resources, want one", len(procs))
	}
	p := procs[0]
	if p["artifact"] != "program" || !reflect.DeepEqual(p["run"], []any{"./mesh-delivery-teller"}) {
		t.Errorf("process = %v", p)
	}
	env, _ := p["env"].(map[string]any)
	if len(env) != 1 || env["MESH_BROKER_FILE"] != "${dir:state}/broker" {
		t.Errorf("env = %v", p["env"])
	}
	if _, bus := p["bus"]; bus {
		t.Errorf("the process declares a bus: it runs on its own broker credential")
	}
	if len(m.Build.Artifacts) != 1 {
		t.Fatalf("artifacts = %+v", m.Build.Artifacts)
	}
	a := m.Build.Artifacts[0]
	if st, err := os.Stat(a.From); err != nil || !st.IsDir() || a.Binary != "mesh-delivery-teller" || !strings.HasSuffix(a.From, a.Binary) {
		t.Errorf("artifact = %+v", a)
	}
}

func TestServesNoRequestSubjectAndHoldsNoTicker(t *testing.T) { // 1240/AC3 (ADR 0437 §8)
	forbidden := []string{"Subscribe(", "QueueSubscribe", "ChanSubscribe", "time.NewTicker", "time.Tick", "time.NewTimer", "time.AfterFunc", "time.After(", "time.Sleep"}
	var files int
	for _, root := range []string{"cmd", "internal"} {
		err := filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
			if os.IsNotExist(err) {
				return fs.SkipDir
			}
			if err != nil || d.IsDir() || !strings.HasSuffix(path, ".go") || strings.HasSuffix(path, "_test.go") {
				return err
			}
			files++
			src, err := os.ReadFile(path)
			if err != nil {
				return err
			}
			for _, f := range forbidden {
				if strings.Contains(string(src), f) {
					t.Errorf("%s holds %s: the teller serves no request subject and holds no timer", path, f)
				}
			}
			return nil
		})
		if err != nil {
			t.Fatal(err)
		}
	}
	if files < 1 {
		t.Fatalf("read %d source files, want the program's", files)
	}
}