package stdio

import (
	"bufio"
	"encoding/json"
	"io"
	"testing"
	"time"

	"git.novox.be/novox/mesh-sdk/go/buscalls"
)

// callWith serves one tool that answers the caller CallerOf reads from its arguments, sends it one tools/call
// with the params given, and returns the caller it answered.
func callWith(t *testing.T, params map[string]any) string {
	caller, _ := callAnswering(t, params)
	return caller
}

// callAnswering is callWith answering the call's id CallIDOf read too.
func callAnswering(t *testing.T, params map[string]any) (string, string) {
	servesAlone(t)
	t.Helper()
	inR, inW := io.Pipe()
	outR, outW := io.Pipe()
	go func() {
		_ = ServeOn("tracker", []Tool{{Name: "who", Run: func(args map[string]any) (any, error) {
			return map[string]any{"caller": CallerOf(args), "call": CallIDOf(args)}, nil
		}}}, inR, outW)
	}()
	defer inW.Close()
	b, _ := json.Marshal(map[string]any{"jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": params})
	_, _ = inW.Write(append(b, '\n'))
	lines := bufio.NewScanner(outR)
	done := make(chan [2]string, 1)
	go func() {
		if lines.Scan() {
			var m struct {
				Result struct {
					Content []struct {
						Text string `json:"text"`
					} `json:"content"`
				} `json:"result"`
			}
			_ = json.Unmarshal(lines.Bytes(), &m)
			var answer struct {
				Caller string `json:"caller"`
				Call   string `json:"call"`
			}
			if len(m.Result.Content) > 0 {
				_ = json.Unmarshal([]byte(m.Result.Content[0].Text), &answer)
			}
			done <- [2]string{answer.Caller, answer.Call}
		}
	}()
	select {
	case got := <-done:
		return got[0], got[1]
	case <-time.After(3 * time.Second):
		t.Fatal("the bundle did not answer the call")
		return "", ""
	}
}

// **A tool reads its caller from the runtime, never from the call's arguments** (novox/hq issue 365): the
// runtime names the caller it took from the subject the call arrived on in the call's `_meta`, and CallerOf
// hands it to the tool by the arguments the tool was given.
func TestAToolReadsTheCallerTheRuntimeNamed(t *testing.T) {
	got := callWith(t, map[string]any{"name": "who", "arguments": map[string]any{"title": "x"},
		"_meta": map[string]any{MetaCaller: "shanks.node-tools"}})
	if got != "shanks.node-tools" {
		t.Fatalf("the tool read caller %q, want the one the runtime named", got)
	}
	// The call's id is the runtime's too (ADR 0597 §7): read from `_meta`, never from the arguments, and none when it
	// is not one token.
	for _, c := range []struct {
		args, meta map[string]any
		want       string
	}{
		{map[string]any{}, map[string]any{MetaCaller: "shanks.node-tools", MetaCall: "c-7Hq2"}, "c-7Hq2"},
		{map[string]any{}, map[string]any{MetaCaller: "shanks.node-tools"}, ""},
		{map[string]any{MetaCall: "c-forged"}, map[string]any{}, ""},
		{map[string]any{}, map[string]any{MetaCall: "a b"}, ""},
		{map[string]any{}, map[string]any{MetaCall: 7}, ""},
	} {
		if _, call := callAnswering(t, map[string]any{"name": "who", "arguments": c.args, "_meta": c.meta}); call != c.want {
			t.Errorf("args %v, meta %v: the tool read call %q, want %q", c.args, c.meta, call, c.want)
		}
	}
	if CallIDOf(map[string]any{"x": 1}) != "" || CallIDOf(nil) != "" {
		t.Error("arguments no call was handed have a call id")
	}
	if MetaCall != buscalls.MetaCall {
		t.Errorf("the call id's place is %q here and %q in buscalls", MetaCall, buscalls.MetaCall)
	}
}

// A caller named in the arguments is not the caller: an argument is the caller's to write.
func TestACallerInTheArgumentsIsNeverTheCaller(t *testing.T) {
	got := callWith(t, map[string]any{"name": "who", "arguments": map[string]any{"caller": "novox.node-tools",
		"_meta": map[string]any{MetaCaller: "novox.node-tools"}, MetaCaller: "novox.node-tools"}})
	if got != Unproven {
		t.Fatalf("a caller the arguments claimed was read as %q, want %q", got, Unproven)
	}
	got = callWith(t, map[string]any{"name": "who", "arguments": map[string]any{"caller": "novox.node-tools"},
		"_meta": map[string]any{MetaCaller: "shanks.node-tools"}})
	if got != "shanks.node-tools" {
		t.Fatalf("with a caller in the arguments the tool read %q, want the runtime's", got)
	}
	// A module's trusted list of callers (issue 774, ADR 0563 §8) grants the callers it names as the runtime proved them:
	// a module on any machine, <machine>.<module> exactly, person.<name> exactly; no wildcard, never one unproven.
	callers, err := ParseCallers([]byte(`{"callers":["node-tools","ace.claude-code","person.jo","*"]}`))
	if err != nil {
		t.Fatal(err)
	}
	for caller, want := range map[string]bool{"shanks.node-tools": true, "ace.claude-code": true, "g14.claude-code": false,
		"person.jo": true, "person.node-tools": false, Unproven: false, "": false, "novox.mesh-vault": false} {
		if callers.Allows(caller) != want {
			t.Errorf("%q allowed: %v, want %v", caller, !want, want)
		}
	}
	if _, err := ParseCallers([]byte(`{"callers":["x"],"more":1}`)); err == nil {
		t.Error("a list with a field it does not know was read")
	}
}

// A runtime that names no caller — one from before issue 365, or a call on the subject that names none — is
// said as Unproven, explicitly; a caller that is not a bus user's name is Unproven too.
func TestACallTheRuntimeNamedNoCallerForIsUnproven(t *testing.T) {
	for _, params := range []map[string]any{
		{"name": "who", "arguments": map[string]any{}},
		{"name": "who"},
		{"name": "who", "arguments": map[string]any{}, "_meta": map[string]any{}},
		{"name": "who", "arguments": map[string]any{}, "_meta": map[string]any{MetaCaller: ""}},
		{"name": "who", "arguments": map[string]any{}, "_meta": map[string]any{MetaCaller: "a b"}},
		{"name": "who", "arguments": map[string]any{}, "_meta": map[string]any{MetaCaller: 7}},
	} {
		if got := callWith(t, params); got != Unproven {
			t.Errorf("%v: the tool read caller %q, want %q", params, got, Unproven)
		}
	}
}

// Arguments the runtime never handed a tool have no caller.
func TestArgumentsOfNoCallHaveNoCaller(t *testing.T) {
	if got := CallerOf(map[string]any{"x": 1}); got != Unproven {
		t.Fatalf("CallerOf of a map no call was given answered %q", got)
	}
	if got := CallerOf(nil); got != Unproven {
		t.Fatalf("CallerOf(nil) answered %q", got)
	}
}