package opencode

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"
)

// fakeAPIServer — минимальный фейк opencode serve HTTP API v1.17.
type fakeAPIServer struct {
	messages   []sessionMessage
	failCreate bool
	failVerify bool
}

func (f *fakeAPIServer) handler() http.Handler {
	mux := http.NewServeMux()
	mux.HandleFunc("/api/session", func(w http.ResponseWriter, r *http.Request) {
		if f.failCreate {
			http.Error(w, "boom", http.StatusInternalServerError)
			return
		}
		writeJSON(w, map[string]any{"data": map[string]any{"id": "sess-fake"}})
	})
	mux.HandleFunc("/api/session/{id}/prompt", func(w http.ResponseWriter, _ *http.Request) {
		writeJSON(w, map[string]any{"data": map[string]any{}})
	})
	mux.HandleFunc("/api/session/{id}/wait", func(w http.ResponseWriter, _ *http.Request) {
		writeJSON(w, map[string]any{})
	})
	mux.HandleFunc("/api/session/{id}/interrupt", func(w http.ResponseWriter, _ *http.Request) {
		writeJSON(w, map[string]any{})
	})
	mux.HandleFunc("/api/session/{id}/message", func(w http.ResponseWriter, _ *http.Request) {
		if len(f.messages) == 0 {
			writeJSON(w, map[string]any{"data": []sessionMessage{}})
			return
		}
		writeJSON(w, map[string]any{"data": f.messages})
	})
	return mux
}

func writeJSON(w http.ResponseWriter, v any) {
	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(v)
}

// textPart — анонимная text-часть assistant-сообщения.
func textPart(s string) struct {
	Type string `json:"type"`
	Text string `json:"text"`
} {
	return struct {
		Type string `json:"type"`
		Text string `json:"text"`
	}{Type: "text", Text: s}
}

func fakeClient(t *testing.T, f *fakeAPIServer) *Client {
	t.Helper()
	ts := httptest.NewServer(f.handler())
	t.Cleanup(ts.Close)
	return &Client{BaseURL: ts.URL}
}

func TestClient_CreateSession(t *testing.T) {
	c := fakeClient(t, &fakeAPIServer{})
	id, err := c.CreateSession(context.Background(), "ratatoskr-analyst")
	if err != nil {
		t.Fatalf("CreateSession err: %v", err)
	}
	if id != "sess-fake" {
		t.Errorf("id = %q, want sess-fake", id)
	}
}

func TestClient_CreateSessionFail(t *testing.T) {
	c := fakeClient(t, &fakeAPIServer{failCreate: true})
	if _, err := c.CreateSession(context.Background(), "x"); err == nil {
		t.Fatal("CreateSession должен упасть при 500, а не nil")
	}
}

func TestClient_Verdict(t *testing.T) {
	c := fakeClient(t, &fakeAPIServer{
		messages: []sessionMessage{{Type: "assistant", Content: []struct {
			Type string `json:"type"`
			Text string `json:"text"`
		}{textPart(`{"phase":"ready"}`)}}},
	})
	vd, err := c.Verdict(context.Background(), "sess-fake")
	if err != nil {
		t.Fatalf("Verdict err: %v", err)
	}
	if vd != `{"phase":"ready"}` {
		t.Errorf("verdict = %q, want вердикт модели", vd)
	}
}

func TestClient_VerdictNoText(t *testing.T) {
	c := fakeClient(t, &fakeAPIServer{}) // нет assistant-сообщения с text
	if _, err := c.Verdict(context.Background(), "sess-fake"); err == nil {
		t.Fatal("Verdict должен упасть, когда нет text-части")
	} else {
		var ce *ClientErr
		if !errors.As(err, &ce) {
			t.Errorf("ожидался *ClientErr, got %T", err)
		}
	}
}