package msglib

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"strings"
	"testing"
	"time"
)

func TestSelfCheckSendsProtocolEnvelopeAndDecodesResponse(t *testing.T) {
	client := newFakeClient(t, "self_check_ok", Config{})

	got, err := client.SelfCheck(context.Background())
	if err != nil {
		t.Fatalf("SelfCheck returned error: %v", err)
	}
	if got.SidecarName != "MsgLibReadSidecar" {
		t.Fatalf("SidecarName = %q, want MsgLibReadSidecar", got.SidecarName)
	}
	if got.Protocol != Protocol {
		t.Fatalf("Protocol = %q, want %q", got.Protocol, Protocol)
	}
	if got.ProcessBits != 32 || !got.ReadOnly || got.MutatesDB {
		t.Fatalf("unexpected safety fields: bits=%d read_only=%v mutates_db=%v", got.ProcessBits, got.ReadOnly, got.MutatesDB)
	}
}

func TestDisplaySourcesPassesConfiguredPathsAndDecodesMetadata(t *testing.T) {
	cfg := Config{
		SQLiteDLLPath: `C:\fixture\System.Data.SQLite.dll`,
		DBPath:        `C:\fixture\MsgLib.db`,
		Password:      "123",
	}
	client := newFakeClient(t, "display_sources_ok", cfg)

	got, err := client.DisplaySources(context.Background())
	if err != nil {
		t.Fatalf("DisplaySources returned error: %v", err)
	}
	if len(got) != 2 {
		t.Fatalf("len(DisplaySources) = %d, want 2", len(got))
	}
	if got[0].Source != "contacts_roster" || got[0].Table != "TD_Roster" || !got[0].Available {
		t.Fatalf("unexpected first display source: %+v", got[0])
	}
	if strings.Join(got[0].RequiredColumns, ",") != "UserJID,Name" {
		t.Fatalf("required columns = %#v", got[0].RequiredColumns)
	}
	if got[1].Source != "work_group_auth" || got[1].Available {
		t.Fatalf("unexpected second display source: %+v", got[1])
	}
}

func TestDisplayEntitiesPassesBoundedArgsAndDecodesMetadata(t *testing.T) {
	cfg := Config{
		SQLiteDLLPath: `C:\fixture\System.Data.SQLite.dll`,
		DBPath:        `C:\fixture\MsgLib.db`,
		Password:      "123",
	}
	client := newFakeClient(t, "display_entities_ok", cfg)

	got, err := client.DisplayEntities(context.Background(), DisplayEntitiesOptions{EntityType: "contacts", Query: "alice", Limit: 2})
	if err != nil {
		t.Fatalf("DisplayEntities returned error: %v", err)
	}
	if len(got) != 2 {
		t.Fatalf("len(DisplayEntities) = %d, want 2", len(got))
	}
	if got[0].EntityType != "contacts" || got[0].SourceTable != "TD_Roster" || got[0].JID != "alice@example" || got[0].DisplayName != "Alice" {
		t.Fatalf("unexpected first entity: %+v", got[0])
	}
	if got[0].Confidence <= 0 || strings.Join(got[0].MatchedColumns, ",") != "JId,Nick" {
		t.Fatalf("unexpected first entity metadata: %+v", got[0])
	}
	if got[1].SourceTable != "tblRecent" || got[1].JID != "recent@example" || got[1].DisplayName != "Recent Alice" {
		t.Fatalf("unexpected second entity: %+v", got[1])
	}
}

func TestDisplayEntitiesRejectsUnsupportedEntityType(t *testing.T) {
	client := newFakeClient(t, "display_entities_ok", Config{})

	_, err := client.DisplayEntities(context.Background(), DisplayEntitiesOptions{EntityType: "messages", Limit: 5})
	if err == nil {
		t.Fatal("DisplayEntities returned nil error, want unsupported entity_type error")
	}
	if !strings.Contains(err.Error(), "entity_type") {
		t.Fatalf("DisplayEntities error = %v, want entity_type context", err)
	}
}

func TestClientReturnsStructuredSidecarError(t *testing.T) {
	client := newFakeClient(t, "sidecar_error", Config{})

	_, err := client.SelfCheck(context.Background())
	if err == nil {
		t.Fatal("SelfCheck returned nil error, want sidecar error")
	}
	var sidecarErr *SidecarError
	if !errors.As(err, &sidecarErr) {
		t.Fatalf("error %T %[1]v does not wrap *SidecarError", err)
	}
	if sidecarErr.Code != "DB_OPEN_FAILED" || !strings.Contains(sidecarErr.Message, "read-only open failed") {
		t.Fatalf("unexpected sidecar error: %+v", sidecarErr)
	}
}

func TestClientTimeoutStopsSidecar(t *testing.T) {
	client := newFakeClient(t, "hang", Config{Timeout: 150 * time.Millisecond})

	_, err := client.SelfCheck(context.Background())
	if err == nil {
		t.Fatal("SelfCheck returned nil error, want timeout")
	}
	if !errors.Is(err, context.DeadlineExceeded) && !strings.Contains(strings.ToLower(err.Error()), "deadline") {
		t.Fatalf("SelfCheck error = %v, want deadline exceeded", err)
	}
}

func TestConfigFromEnvReadsSidecarShape(t *testing.T) {
	t.Setenv("ISPHERE_MSGLIB_SIDECAR_EXE", `C:\tools\MsgLibReadSidecar.exe`)
	t.Setenv("ISPHERE_MSGLIB_SQLITE_DLL", `C:\tools\System.Data.SQLite.dll`)
	t.Setenv("ISPHERE_MSGLIB_DB", `C:\copy\MsgLib.db`)

	cfg, err := ConfigFromEnv()
	if err != nil {
		t.Fatalf("ConfigFromEnv returned error: %v", err)
	}
	if cfg.SidecarPath != `C:\tools\MsgLibReadSidecar.exe` {
		t.Fatalf("SidecarPath = %q", cfg.SidecarPath)
	}
	if cfg.SQLiteDLLPath != `C:\tools\System.Data.SQLite.dll` || cfg.DBPath != `C:\copy\MsgLib.db` {
		t.Fatalf("unexpected DB config: %+v", cfg)
	}
	if cfg.Password != "123" {
		t.Fatalf("Password = %q, want default 123", cfg.Password)
	}
}

func newFakeClient(t *testing.T, mode string, overrides Config) *Client {
	t.Helper()
	exe, err := os.Executable()
	if err != nil {
		t.Fatalf("os.Executable: %v", err)
	}
	cfg := overrides
	cfg.SidecarPath = exe
	cfg.SidecarArgs = []string{"-test.run=TestFakeSidecarProcess", "--"}
	cfg.ExtraEnv = append(cfg.ExtraEnv, "ISPHERE_MSGLIB_FAKE_SIDECAR=1", "ISPHERE_MSGLIB_FAKE_MODE="+mode)
	if cfg.Timeout == 0 {
		cfg.Timeout = 2 * time.Second
	}
	return NewClient(cfg)
}

func TestFakeSidecarProcess(t *testing.T) {
	if os.Getenv("ISPHERE_MSGLIB_FAKE_SIDECAR") != "1" {
		return
	}
	os.Exit(fakeSidecarMain())
}

func fakeSidecarMain() int {
	mode := os.Getenv("ISPHERE_MSGLIB_FAKE_MODE")
	if mode == "hang" {
		time.Sleep(5 * time.Second)
		return 0
	}

	var req map[string]any
	if err := json.NewDecoder(os.Stdin).Decode(&req); err != nil {
		fmt.Fprintf(os.Stderr, "decode request: %v\n", err)
		return 2
	}
	protocol, _ := req["protocol"].(string)
	op, _ := req["op"].(string)
	requestID, _ := req["request_id"].(string)
	if protocol != Protocol || op == "" || requestID == "" {
		fmt.Fprintf(os.Stderr, "bad envelope: protocol=%q op=%q request_id=%q\n", protocol, op, requestID)
		return 2
	}

	if mode == "sidecar_error" {
		return writeFakeResponse(map[string]any{
			"protocol":   Protocol,
			"request_id": requestID,
			"op":         op,
			"ok":         false,
			"data":       nil,
			"error": map[string]any{
				"code":    "DB_OPEN_FAILED",
				"message": "read-only open failed",
			},
			"warnings": []any{},
		})
	}

	switch op {
	case "self_check":
		return writeFakeResponse(map[string]any{
			"protocol":   Protocol,
			"request_id": requestID,
			"op":         op,
			"ok":         true,
			"data": map[string]any{
				"sidecar_name":    "MsgLibReadSidecar",
				"sidecar_version": "0.1.0",
				"protocol":        Protocol,
				"process_bits":    32,
				"read_only":       true,
				"mutates_db":      false,
			},
			"error":    nil,
			"warnings": []any{},
		})
	case "display_sources":
		args, _ := req["args"].(map[string]any)
		if args["sqlite_dll_path"] != `C:\fixture\System.Data.SQLite.dll` || args["db_path"] != `C:\fixture\MsgLib.db` || args["password"] != "123" {
			fmt.Fprintf(os.Stderr, "bad display_sources args: %#v\n", args)
			return 2
		}
		return writeFakeResponse(map[string]any{
			"protocol":   Protocol,
			"request_id": requestID,
			"op":         op,
			"ok":         true,
			"data": map[string]any{
				"metadata_only":                true,
				"read_only":                    true,
				"message_body_values_returned": false,
				"display_sources": []any{
					map[string]any{"source": "contacts_roster", "table": "TD_Roster", "available": true, "required_columns": []any{"UserJID", "Name"}, "present_columns": []any{"UserJID", "Name", "Mobile"}},
					map[string]any{"source": "work_group_auth", "table": "TD_WorkGroupAuth", "available": false, "required_columns": []any{"GroupJID", "GroupName"}, "present_columns": []any{"GroupJID"}},
				},
			},
			"error":    nil,
			"warnings": []any{},
		})
	case "display_entities":
		args, _ := req["args"].(map[string]any)
		if args["sqlite_dll_path"] != `C:\fixture\System.Data.SQLite.dll` || args["db_path"] != `C:\fixture\MsgLib.db` || args["password"] != "123" || args["entity_type"] != "contacts" || args["query"] != "alice" || args["limit"] != float64(2) {
			fmt.Fprintf(os.Stderr, "bad display_entities args: %#v\n", args)
			return 2
		}
		return writeFakeResponse(map[string]any{
			"protocol":   Protocol,
			"request_id": requestID,
			"op":         op,
			"ok":         true,
			"data": map[string]any{
				"metadata_only": true,
				"read_only":     true,
				"entity_type":   "contacts",
				"limit":         2,
				"result_count":  2,
				"entities": []any{
					map[string]any{"entity_type": "contacts", "source_table": "TD_Roster", "jid": "alice@example", "display_name": "Alice", "confidence": 0.95, "matched_columns": []any{"JId", "Nick"}},
					map[string]any{"entity_type": "contacts", "source_table": "tblRecent", "jid": "recent@example", "display_name": "Recent Alice", "confidence": 0.70, "matched_columns": []any{"PersonId", "PersonName"}},
				},
			},
			"error":    nil,
			"warnings": []any{},
		})
	default:
		fmt.Fprintf(os.Stderr, "unexpected op: %s\n", op)
		return 2
	}
}

func writeFakeResponse(resp map[string]any) int {
	if err := json.NewEncoder(os.Stdout).Encode(resp); err != nil {
		fmt.Fprintf(os.Stderr, "encode response: %v\n", err)
		return 2
	}
	return 0
}