package compute

import (
	"errors"
	"fmt"
	"strings"
	"testing"

	"github.com/Masterminds/semver/v3"
)

func TestRustToolchainConstraint(t *testing.T) {
	const constraint = ">= 1.78 != 1.91.0 < 1.92"

	tests := []struct {
		name              string
		rustVersion       string
		wantErr           bool
		wantErrorContains string
	}{
		{
			name:              "rejects 1.91.0",
			rustVersion:       "1.91.0",
			wantErr:           true,
			wantErrorContains: "not compatible",
		},
		{
			name:        "allows 1.90.1",
			rustVersion: "1.90.1",
			wantErr:     false,
		},
		{
			name:        "allows 1.91.1",
			rustVersion: "1.91.1",
			wantErr:     false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// Parse the Rust version being tested
			v, err := semver.NewVersion(tt.rustVersion)
			if err != nil {
				t.Fatalf("failed to parse version: %v", err)
			}

			// Parse the semver constraint (shared across tests)
			c, err := semver.NewConstraint(constraint)
			if err != nil {
				t.Fatalf("failed to parse constraint: %v", err)
			}

			// Validate version against constraint
			valid, errs := c.Validate(v)

			var resultErr error
			if !valid {
				for _, e := range errs {
					if strings.Contains(e.Error(), "is greater than") {
						resultErr = fmt.Errorf("version '%s' of Rust has not been validated for use with Fastly Compute", v)
					}
					if strings.Contains(e.Error(), "is equal to") {
						resultErr = fmt.Errorf("version '%s' of Rust is not compatible with Fastly Compute", v)
					}
				}
				if resultErr == nil {
					resultErr = fmt.Errorf("the Rust version requirement was not satisfied: '%w'", errors.Join(errs...))
				}
			}

			// Check if error presence matches expectation
			if (resultErr != nil) != tt.wantErr {
				t.Errorf("unexpected error result: got %v, wantErr %v", resultErr, tt.wantErr)
			}

			// If error was expected, check it contains the expected string
			if tt.wantErr && tt.wantErrorContains != "" && !strings.Contains(resultErr.Error(), tt.wantErrorContains) {
				t.Errorf("expected error to contain %q, got %q", tt.wantErrorContains, resultErr.Error())
			}
		})
	}
}