package graph

import (
	"encoding/json"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"gitlab.com/unboundsoftware/schemas/graph/model"
)

func TestGenerateCosmoRouterConfig(t *testing.T) {
	tests := []struct {
		name      string
		subGraphs []*model.SubGraph
		wantErr   bool
		validate  func(t *testing.T, config string)
	}{
		{
			name: "single subgraph with all fields",
			subGraphs: []*model.SubGraph{
				{
					Service: "test-service",
					URL:     stringPtr("http://localhost:4001/query"),
					WsURL:   stringPtr("ws://localhost:4001/query"),
					Sdl:     "type Query { test: String }",
				},
			},
			wantErr: false,
			validate: func(t *testing.T, config string) {
				var result map[string]interface{}
				err := json.Unmarshal([]byte(config), &result)
				require.NoError(t, err, "Config should be valid JSON")

				assert.Equal(t, "1", result["version"], "Version should be 1")

				subgraphs, ok := result["subgraphs"].([]interface{})
				require.True(t, ok, "subgraphs should be an array")
				require.Len(t, subgraphs, 1, "Should have 1 subgraph")

				sg := subgraphs[0].(map[string]interface{})
				assert.Equal(t, "test-service", sg["name"])
				assert.Equal(t, "http://localhost:4001/query", sg["routing_url"])
				assert.Equal(t, "type Query { test: String }", sg["sdl"])

				subscription, ok := sg["subscription"].(map[string]interface{})
				require.True(t, ok, "Should have subscription config")
				assert.Equal(t, "ws://localhost:4001/query", subscription["url"])
				assert.Equal(t, "ws", subscription["protocol"])
				assert.Equal(t, "graphql-ws", subscription["websocket_subprotocol"])
			},
		},
		{
			name: "multiple subgraphs",
			subGraphs: []*model.SubGraph{
				{
					Service: "service-1",
					URL:     stringPtr("http://localhost:4001/query"),
					Sdl:     "type Query { field1: String }",
				},
				{
					Service: "service-2",
					URL:     stringPtr("http://localhost:4002/query"),
					Sdl:     "type Query { field2: String }",
				},
				{
					Service: "service-3",
					URL:     stringPtr("http://localhost:4003/query"),
					WsURL:   stringPtr("ws://localhost:4003/query"),
					Sdl:     "type Subscription { updates: String }",
				},
			},
			wantErr: false,
			validate: func(t *testing.T, config string) {
				var result map[string]interface{}
				err := json.Unmarshal([]byte(config), &result)
				require.NoError(t, err)

				subgraphs := result["subgraphs"].([]interface{})
				assert.Len(t, subgraphs, 3, "Should have 3 subgraphs")

				// Check first service has no subscription
				sg1 := subgraphs[0].(map[string]interface{})
				assert.Equal(t, "service-1", sg1["name"])
				_, hasSubscription := sg1["subscription"]
				assert.False(t, hasSubscription, "service-1 should not have subscription config")

				// Check third service has subscription
				sg3 := subgraphs[2].(map[string]interface{})
				assert.Equal(t, "service-3", sg3["name"])
				subscription, hasSubscription := sg3["subscription"]
				assert.True(t, hasSubscription, "service-3 should have subscription config")
				assert.NotNil(t, subscription)
			},
		},
		{
			name: "subgraph with no URL",
			subGraphs: []*model.SubGraph{
				{
					Service: "test-service",
					URL:     nil,
					WsURL:   nil,
					Sdl:     "type Query { test: String }",
				},
			},
			wantErr: false,
			validate: func(t *testing.T, config string) {
				var result map[string]interface{}
				err := json.Unmarshal([]byte(config), &result)
				require.NoError(t, err)

				subgraphs := result["subgraphs"].([]interface{})
				sg := subgraphs[0].(map[string]interface{})

				// Should not have routing_url or subscription fields if URLs are nil
				_, hasRoutingURL := sg["routing_url"]
				assert.False(t, hasRoutingURL, "Should not have routing_url when URL is nil")

				_, hasSubscription := sg["subscription"]
				assert.False(t, hasSubscription, "Should not have subscription when WsURL is nil")
			},
		},
		{
			name:      "empty subgraphs",
			subGraphs: []*model.SubGraph{},
			wantErr:   false,
			validate: func(t *testing.T, config string) {
				var result map[string]interface{}
				err := json.Unmarshal([]byte(config), &result)
				require.NoError(t, err)

				subgraphs := result["subgraphs"].([]interface{})
				assert.Len(t, subgraphs, 0, "Should have empty subgraphs array")
			},
		},
		{
			name:      "nil subgraphs",
			subGraphs: nil,
			wantErr:   false,
			validate: func(t *testing.T, config string) {
				var result map[string]interface{}
				err := json.Unmarshal([]byte(config), &result)
				require.NoError(t, err)

				subgraphs := result["subgraphs"].([]interface{})
				assert.Len(t, subgraphs, 0, "Should handle nil subgraphs as empty array")
			},
		},
		{
			name: "complex SDL with multiple types",
			subGraphs: []*model.SubGraph{
				{
					Service: "complex-service",
					URL:     stringPtr("http://localhost:4001/query"),
					Sdl: `
						type Query {
							user(id: ID!): User
							users: [User!]!
						}

						type User {
							id: ID!
							name: String!
							email: String!
						}
					`,
				},
			},
			wantErr: false,
			validate: func(t *testing.T, config string) {
				var result map[string]interface{}
				err := json.Unmarshal([]byte(config), &result)
				require.NoError(t, err)

				subgraphs := result["subgraphs"].([]interface{})
				sg := subgraphs[0].(map[string]interface{})
				sdl := sg["sdl"].(string)

				assert.Contains(t, sdl, "type Query")
				assert.Contains(t, sdl, "type User")
				assert.Contains(t, sdl, "email: String!")
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			config, err := GenerateCosmoRouterConfig(tt.subGraphs)

			if tt.wantErr {
				assert.Error(t, err)
				return
			}

			require.NoError(t, err)
			assert.NotEmpty(t, config, "Config should not be empty")

			if tt.validate != nil {
				tt.validate(t, config)
			}
		})
	}
}

func TestConvertSubGraphsToCosmo(t *testing.T) {
	tests := []struct {
		name      string
		subGraphs []*model.SubGraph
		wantLen   int
		validate  func(t *testing.T, result []map[string]interface{})
	}{
		{
			name: "preserves subgraph order",
			subGraphs: []*model.SubGraph{
				{Service: "alpha", URL: stringPtr("http://a"), Sdl: "a"},
				{Service: "beta", URL: stringPtr("http://b"), Sdl: "b"},
				{Service: "gamma", URL: stringPtr("http://c"), Sdl: "c"},
			},
			wantLen: 3,
			validate: func(t *testing.T, result []map[string]interface{}) {
				assert.Equal(t, "alpha", result[0]["name"])
				assert.Equal(t, "beta", result[1]["name"])
				assert.Equal(t, "gamma", result[2]["name"])
			},
		},
		{
			name: "includes SDL exactly as provided",
			subGraphs: []*model.SubGraph{
				{
					Service: "test",
					URL:     stringPtr("http://test"),
					Sdl:     "type Query { special: String! }",
				},
			},
			wantLen: 1,
			validate: func(t *testing.T, result []map[string]interface{}) {
				assert.Equal(t, "type Query { special: String! }", result[0]["sdl"])
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result := convertSubGraphsToCosmo(tt.subGraphs)
			assert.Len(t, result, tt.wantLen)

			if tt.validate != nil {
				tt.validate(t, result)
			}
		})
	}
}

// Helper function for tests
func stringPtr(s string) *string {
	return &s
}