package libraryexecutor

import (
	"context"
	"encoding/json"
	"net"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

func shortSocketDir(t *testing.T) string {
	t.Helper()
	// unix socket 路径上限 ~104 字节，TMPDIR（本机是 .hermes/cache/scratch）太长，
	// 测试里用一个短目录并立刻清理。
	dir, err := os.MkdirTemp("/tmp", "kgex-")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { os.RemoveAll(dir) })
	return dir
}

// 可用性必须来自运行时观测，而不是"配置里写了 socket 路径"。
func TestProbeReadsIdentityFromTheAgentOverTheSocket(t *testing.T) {
	root := shortSocketDir(t)
	socket := filepath.Join(root, "agent.sock")
	listener, err := net.Listen("unix", socket)
	if err != nil {
		t.Fatal(err)
	}
	defer listener.Close()
	go func() {
		for {
			conn, acceptErr := listener.Accept()
			if acceptErr != nil {
				return
			}
			var request map[string]any
			_ = json.NewDecoder(conn).Decode(&request)
			payload, _ := json.Marshal(map[string]any{
				"project": "kgmaint-weknora", "archive_root": "/tmp/kg-e2e/archive",
				"journal_root": "/tmp/kg-e2e/journal", "source_app": "kgmaint-app",
				"source_pg": "kgmaint-postgres", "source_es": "WKNFull-elasticsearch",
				"writers": "app", "busy": true, "degraded": "",
			})
			_ = json.NewEncoder(conn).Encode(map[string]any{"ok": true, "action": "health", "payload": json.RawMessage(payload)})
			conn.Close()
		}
	}()

	observation := Probe(context.Background(), "kgmaint-weknora", socket, 2*time.Second, nil)
	if !observation.Reachable {
		t.Fatalf("observation = %+v", observation)
	}
	if observation.Identity.Project != "kgmaint-weknora" || observation.Identity.SourceApp != "kgmaint-app" || !observation.Busy {
		t.Fatalf("identity = %+v", observation.Identity)
	}
	if observation.Instance != "kgmaint-weknora" || observation.ObservedAt.IsZero() {
		t.Fatalf("observation = %+v", observation)
	}
}

func TestProbeReportsUnreachableAgentWithoutFakingSuccess(t *testing.T) {
	observation := Probe(context.Background(), "kgmaint-weknora", filepath.Join(t.TempDir(), "absent.sock"), time.Second, nil)
	if observation.Reachable || observation.Error == "" {
		t.Fatalf("observation = %+v", observation)
	}
	available, reason := Evaluate(observation, Expectation{Instance: "kgmaint-weknora", Project: "kgmaint-weknora"},
		time.Minute, time.Now().UTC())
	if available || !strings.Contains(reason, "不可达") {
		t.Fatalf("available=%v reason=%q", available, reason)
	}
}

func TestEvaluateRejectsEveryIdentityAndFreshnessProblem(t *testing.T) {
	now := time.Date(2026, 10, 29, 8, 0, 0, 0, time.UTC)
	healthy := Observation{
		Instance: "kgmaint-weknora", Reachable: true, ObservedAt: now,
		Identity: Identity{Project: "kgmaint-weknora", SourceApp: "kgmaint-app"},
	}
	want := Expectation{Instance: "kgmaint-weknora", Project: "kgmaint-weknora"}
	if available, reason := Evaluate(healthy, want, 2*time.Minute, now); !available || reason != "" {
		t.Fatalf("healthy executor rejected: %v %q", available, reason)
	}

	tests := []struct {
		name string
		mut  func(*Observation)
		want func(Expectation) Expectation
		text string
	}{
		{name: "missing instance config", want: func(Expectation) Expectation { return expectEmptyInstance },
			text: "LIBRARY_SOURCE_INSTANCE"},
		{name: "row from another instance", mut: func(o *Observation) { o.Instance = "someone-else" },
			text: "另一个实例"},
		{name: "stale", mut: func(o *Observation) { o.ObservedAt = now.Add(-10 * time.Minute) },
			text: "已过期"},
		{name: "unreachable", mut: func(o *Observation) { o.Reachable = false; o.Error = "socket missing" },
			text: "不可达：socket missing"},
		{name: "project not configured", want: func(Expectation) Expectation { return Expectation{Instance: "kgmaint-weknora"} },
			text: "LIBRARY_SOURCE_PROJECT"},
		{name: "wrong source project", mut: func(o *Observation) { o.Identity.Project = "weknora071full" },
			text: "指向的实例不匹配"},
		{name: "degraded", mut: func(o *Observation) { o.Degraded = "写入者恢复失败" },
			text: "降级状态"},
		{name: "busy", mut: func(o *Observation) { o.Busy = true },
			text: "正在执行另一个封存"},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			observation := healthy
			if test.mut != nil {
				test.mut(&observation)
			}
			expectation := want
			if test.want != nil {
				expectation = test.want(want)
			}
			available, reason := Evaluate(observation, expectation, 2*time.Minute, now)
			if available {
				t.Fatalf("accepted: %+v", observation)
			}
			if !strings.Contains(reason, test.text) {
				t.Fatalf("reason = %q, want it to mention %q", reason, test.text)
			}
		})
	}
}

var expectEmptyInstance = Expectation{Project: "kgmaint-weknora"}