package config

import (
	"reflect"
	"strings"
	"testing"
)

func TestExtractPathParams(t *testing.T) {
	tests := []struct {
		name       string
		prefix     string
		wantParams []string
		wantErr    bool
		errContain string
	}{
		{
			name:       "no params - simple prefix",
			prefix:     "/api/v1",
			wantParams: nil,
			wantErr:    false,
		},
		{
			name:       "no params - empty prefix",
			prefix:     "",
			wantParams: nil,
			wantErr:    false,
		},
		{
			name:       "single param at end",
			prefix:     "/tibr/{name}",
			wantParams: []string{"name"},
			wantErr:    false,
		},
		{
			name:       "single param in middle",
			prefix:     "/api/{version}/users",
			wantParams: []string{"version"},
			wantErr:    false,
		},
		{
			name:       "multiple params",
			prefix:     "/api/{version}/{resource}",
			wantParams: []string{"version", "resource"},
			wantErr:    false,
		},
		{
			name:       "param with hyphen in name",
			prefix:     "/api/{my-param}",
			wantParams: []string{"my-param"},
			wantErr:    false,
		},
		{
			name:       "param with underscore in name",
			prefix:     "/api/{my_param}",
			wantParams: []string{"my_param"},
			wantErr:    false,
		},
		{
			name:       "unmatched open brace",
			prefix:     "/tibr/{name",
			wantErr:    true,
			errContain: "unmatched '{'",
		},
		{
			name:       "unmatched close brace only",
			prefix:     "/tibr/name}",
			wantErr:    true,
			errContain: "unmatched braces",
		},
		{
			name:       "extra close brace after param",
			prefix:     "/tibr/{name}/}extra",
			wantErr:    true,
			errContain: "unmatched braces",
		},
		{
			name:       "empty param name",
			prefix:     "/tibr/{}",
			wantErr:    true,
			errContain: "empty path parameter",
		},
		{
			name:       "param with slash",
			prefix:     "/tibr/{na/me}",
			wantErr:    true,
			errContain: "invalid path parameter",
		},
		{
			name:       "duplicate param name",
			prefix:     "/api/{id}/sub/{id}",
			wantErr:    true,
			errContain: "duplicate path parameter",
		},
		{
			name:       "multiple duplicate close braces",
			prefix:     "/api/{id}}}",
			wantErr:    true,
			errContain: "unmatched braces",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			params, err := ExtractPathParams(tt.prefix)

			if tt.wantErr {
				if err == nil {
					t.Fatalf("expected error containing %q, got nil", tt.errContain)
				}
				if !strings.Contains(err.Error(), tt.errContain) {
					t.Errorf("error = %q, want error containing %q", err.Error(), tt.errContain)
				}
				return
			}

			if err != nil {
				t.Fatalf("unexpected error: %v", err)
			}

			if !reflect.DeepEqual(params, tt.wantParams) {
				t.Errorf("params = %v, want %v", params, tt.wantParams)
			}
		})
	}
}