package link

import (
	"go/parser"
	"go/token"
	"io/fs"
	"path/filepath"
	"strings"
	"testing"

	"github.com/novox/mesh-controller/internal/broker"
)

// Every subject the controller consumes is a kind with a contract, and every test a contract names
// exists (novox/hq to-be 45 Phase 2, ADR 0227 rule 2).
func TestEveryConsumedKindHasAContract(t *testing.T) {
	// What the controller can be handed, from the subjects it is granted and the ones it derives.
	subjects := []string{EnrolSubject, BuiltSubject, ReportSubject("anchor"), AliveSubject("anchor"),
		ToolsAliveSubject("anchor"), "mesh.mod.postgres.event.provisioner.failing"}
	subjects = append(subjects, broker.ControllerFollows...)
	kinds := map[string]bool{}
	for _, s := range subjects {
		kind, known := kindOfSubject(s)
		if !known {
			if strings.Contains(s, "*") {
				continue // a pattern among the follows; its concrete subject is listed above
			}
			t.Errorf("the controller follows %s and has no kind for it", s)
			continue
		}
		kinds[kind] = true
	}
	for kind := range kinds {
		c, ok := Contracts[kind]
		switch {
		case !ok:
			t.Errorf("the controller consumes %s and no contract says how an older one is told from a newer", kind)
		case (c.Ordered == "") == (c.Unordered == ""):
			t.Errorf("%s's contract says neither, or both, how it is ordered and why it need not be: %+v", kind, c)
		case c.Ordered != "" && len(c.Tests) == 0:
			t.Errorf("%s is ordered and no test delivers the newer and then the older", kind)
		}
	}
	for kind := range Contracts {
		if !kinds[kind] {
			t.Errorf("a contract for %s, which the controller does not consume", kind)
		}
	}

	// Every test named exists in this repository.
	exists := map[string]bool{}
	fset := token.NewFileSet()
	err := filepath.WalkDir("../..", func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() && (d.Name() == "vendor" || d.Name() == ".git") {
			return filepath.SkipDir
		}
		if d.IsDir() || !strings.HasSuffix(path, "_test.go") {
			return nil
		}
		f, err := parser.ParseFile(fset, path, nil, 0)
		if err != nil {
			return err
		}
		for name, obj := range f.Scope.Objects {
			if obj.Kind.String() == "func" && strings.HasPrefix(name, "Test") {
				exists[name] = true
			}
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	for kind, c := range Contracts {
		for _, name := range c.Tests {
			if !exists[name] {
				t.Errorf("%s's contract names %s, which no test in this repository is", kind, name)
			}
		}
	}
}