package telemetry

import (
	"encoding/json"
	"testing"

	otellog "go.opentelemetry.io/otel/log"
	sdklog "go.opentelemetry.io/otel/sdk/log"
)

func TestMapSeverity(t *testing.T) {
	tests := []struct {
		input string
		want  otellog.Severity
	}{
		{"trace", otellog.SeverityTrace},
		{"debug", otellog.SeverityDebug},
		{"info", otellog.SeverityInfo},
		{"warn", otellog.SeverityWarn},
		{"warning", otellog.SeverityWarn},
		{"error", otellog.SeverityError},
		{"fatal", otellog.SeverityFatal},
		{"panic", otellog.SeverityFatal2},
		{"unknown", otellog.SeverityInfo},
		{"", otellog.SeverityInfo},
		{"INFO", otellog.SeverityInfo},  // uppercase falls to default
		{"PANIC", otellog.SeverityInfo}, // uppercase falls to default
		{"gibberish", otellog.SeverityInfo},
	}

	for _, tc := range tests {
		t.Run("level_"+tc.input, func(t *testing.T) {
			got := mapSeverity(tc.input)
			if got != tc.want {
				t.Errorf("mapSeverity(%q) = %v, want %v", tc.input, got, tc.want)
			}
		})
	}
}

func newTestBridge(t *testing.T) *LogBridge {
	t.Helper()
	provider := sdklog.NewLoggerProvider()
	t.Cleanup(func() {
		_ = provider.Shutdown(t.Context())
	})
	return &LogBridge{provider: provider}
}

func TestLogBridgeWrite(t *testing.T) {
	tests := []struct {
		name  string
		input interface{} // will be marshaled to JSON; use string for raw input
		raw   string      // if non-empty, use this directly instead of marshaling input
	}{
		{
			name: "valid_json_with_message_level_and_extras",
			input: map[string]interface{}{
				"message": "request handled",
				"level":   "info",
				"method":  "GET",
				"status":  float64(200),
			},
		},
		{
			name: "message_only_no_level",
			input: map[string]interface{}{
				"message": "hello world",
			},
		},
		{
			name: "level_only_no_message",
			input: map[string]interface{}{
				"level": "error",
			},
		},
		{
			name:  "empty_json_object",
			input: map[string]interface{}{},
		},
		{
			name: "string_float64_bool_attributes",
			input: map[string]interface{}{
				"message":  "test",
				"level":    "debug",
				"str_val":  "hello",
				"num_val":  float64(3.14),
				"bool_val": true,
			},
		},
		{
			name: "complex_nested_object_attribute",
			input: map[string]interface{}{
				"message": "nested",
				"level":   "warn",
				"nested":  map[string]interface{}{"foo": "bar", "n": float64(1)},
			},
		},
		{
			name: "time_field_skipped_in_attributes",
			input: map[string]interface{}{
				"message": "with time",
				"level":   "info",
				"time":    "2025-01-01T00:00:00Z",
				"extra":   "kept",
			},
		},
		{
			name: "malformed_json",
			raw:  "this is not json at all",
		},
		{
			name: "malformed_json_partial",
			raw:  `{"broken":`,
		},
		{
			name: "array_attribute_marshaled_as_string",
			input: map[string]interface{}{
				"message": "arrays",
				"tags":    []interface{}{"a", "b"},
			},
		},
		{
			name: "null_value_attribute",
			input: map[string]interface{}{
				"message": "nulls",
				"val":     nil,
			},
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			bridge := newTestBridge(t)

			var p []byte
			if tc.raw != "" {
				p = []byte(tc.raw)
			} else {
				var err error
				p, err = json.Marshal(tc.input)
				if err != nil {
					t.Fatalf("failed to marshal test input: %v", err)
				}
			}

			n, err := bridge.Write(p)
			if n != len(p) {
				t.Errorf("Write() returned n=%d, want %d", n, len(p))
			}
			if err != nil {
				t.Errorf("Write() returned err=%v, want nil", err)
			}
		})
	}
}

func TestLogBridgeWriteAlwaysReturnsLenAndNil(t *testing.T) {
	bridge := newTestBridge(t)

	inputs := [][]byte{
		[]byte(`{"message":"ok","level":"info"}`),
		[]byte(`not json`),
		[]byte(`{}`),
		[]byte(``),
		[]byte(`[]`),
	}

	for _, p := range inputs {
		n, err := bridge.Write(p)
		if n != len(p) {
			t.Errorf("Write(%q) n=%d, want %d", string(p), n, len(p))
		}
		if err != nil {
			t.Errorf("Write(%q) err=%v, want nil", string(p), err)
		}
	}
}