package api

import (
	"go/ast"
	"go/parser"
	"go/token"
	"net/http"
	"strconv"
	"strings"
	"testing"

	"gitea.dooplex.hu/admin/felhom-hub/internal/store"
)

// apiSwitchRoutes reads ServeHTTP's route switch from handler.go: one apiRoute (method + match) per case, in order.
func apiSwitchRoutes(t *testing.T) []apiRoute {
	t.Helper()
	f, err := parser.ParseFile(token.NewFileSet(), "handler.go", nil, 0)
	if err != nil {
		t.Fatal(err)
	}
	var sw *ast.SwitchStmt
	for _, d := range f.Decls {
		if fd, ok := d.(*ast.FuncDecl); ok && fd.Name.Name == "ServeHTTP" && fd.Recv != nil {
			for _, st := range fd.Body.List {
				if s, ok := st.(*ast.SwitchStmt); ok && s.Tag == nil {
					sw = s
					break
				}
			}
		}
	}
	if sw == nil {
		t.Fatal("ServeHTTP route switch not found in handler.go")
	}
	lit := func(e ast.Expr) string {
		bl, ok := e.(*ast.BasicLit)
		if !ok {
			t.Fatalf("route predicate argument is not a literal at %v", e.Pos())
		}
		v, _ := strconv.Unquote(bl.Value)
		return v
	}
	var conj func(e ast.Expr) []ast.Expr
	conj = func(e ast.Expr) []ast.Expr {
		if b, ok := e.(*ast.BinaryExpr); ok && b.Op == token.LAND {
			return append(conj(b.X), conj(b.Y)...)
		}
		return []ast.Expr{e}
	}
	var out []apiRoute
	for _, c := range sw.Body.List {
		cc := c.(*ast.CaseClause)
		if cc.List == nil {
			continue // default: 404
		}
		if len(cc.List) != 1 {
			t.Fatalf("case at %v has %d expressions; one route per case", cc.Pos(), len(cc.List))
		}
		var r apiRoute
		for _, p := range conj(cc.List[0]) {
			switch x := p.(type) {
			case *ast.BinaryExpr:
				if x.Op != token.EQL {
					t.Fatalf("unrecognised predicate at %v", x.Pos())
				}
				if sel, ok := x.Y.(*ast.SelectorExpr); ok && strings.HasPrefix(sel.Sel.Name, "Method") {
					r.Method = strings.ToUpper(strings.TrimPrefix(sel.Sel.Name, "Method"))
				} else {
					r.Exact = lit(x.Y)
				}
			case *ast.CallExpr:
				switch x.Fun.(*ast.SelectorExpr).Sel.Name {
				case "HasPrefix":
					r.Prefix = lit(x.Args[1])
				case "HasSuffix":
					r.Suffix = lit(x.Args[1])
				case "Contains":
					r.Contains = lit(x.Args[1])
				default:
					t.Fatalf("unrecognised predicate at %v", x.Pos())
				}
			default:
				t.Fatalf("unrecognised predicate at %v", p.Pos())
			}
		}
		out = append(out, r)
	}
	return out
}

// TestAPIRouteTable_MatchesSwitch is R-952 for /api/v1: a route added to the switch without deciding who may call it
// fails here. RED-PROOF: delete the GET /customers entry from apiRoutes → FAIL at index 36.
func TestAPIRouteTable_MatchesSwitch(t *testing.T) {
	sw := apiSwitchRoutes(t)
	if len(sw) < 40 {
		t.Fatalf("parsed only %d routes — the parser lost the switch", len(sw))
	}
	n := len(sw)
	if len(apiRoutes) > n {
		n = len(apiRoutes)
	}
	for i := 0; i < n; i++ {
		var a, b apiRoute
		if i < len(sw) {
			a = sw[i]
		}
		if i < len(apiRoutes) {
			b = apiRoutes[i]
			b.Auth, b.Why = "", ""
			if apiRoutes[i].Auth == "" {
				t.Errorf("route %d has no Auth class", i)
			}
			if apiRoutes[i].Auth == authPublic && apiRoutes[i].Why == "" {
				t.Errorf("public route %d has no reason", i)
			}
		}
		if a != b {
			t.Fatalf("route %d: switch has %+v, table has %+v — classify it in routes.go in the switch's order", i, a, b)
		}
	}
}

func apiSample(r apiRoute) string {
	if r.Exact != "" {
		return r.Exact
	}
	id := "c1"
	if strings.Contains(r.Prefix, "hosts/") {
		id = "h1"
	}
	p := r.Prefix + id
	if r.Contains != "" {
		p += r.Contains + "j1"
	}
	return p + r.Suffix
}

// TestAPIRoutes_NoCredential: every non-public route, called with no credential for a customer and a host that
// EXIST (so a 404 cannot stand in for a refusal), answers 401 or 403.
// RED-PROOF: make requireGlobalKey return true → GET /customers answers 200.
func TestAPIRoutes_NoCredential(t *testing.T) {
	h, st, _ := newTestHandler(t)
	st.SaveCustomerConfig(&store.CustomerConfig{CustomerID: "c1", APIKey: "ckey", RetrievalPassword: "pass-phrase"})
	st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "HKEY"})
	n := 0
	for _, r := range apiRoutes {
		if r.Auth == authPublic {
			continue
		}
		n++
		// A body naming the existing household and host, so a route that reads its subject from the body
		// reaches its credential check instead of a 400.
		rr := do(h, r.Method, apiSample(r), "", `{"customer_id":"c1","host_id":"h1"}`)
		if rr.Code != http.StatusUnauthorized && rr.Code != http.StatusForbidden {
			t.Errorf("%s %s (%s) with no credential: %d %q, want 401/403", r.Method, apiSample(r), r.Auth, rr.Code, strings.TrimSpace(rr.Body.String()))
		}
	}
	if n < 40 {
		t.Fatalf("only %d routes checked", n)
	}
}

// TestAPI_AccessTokenIsRefusedEverywhere: an operator access token reaches no box-API route — not a box route, not a
// global-key route, not the public one. RED-PROOF: remove the fhp_ check in ServeHTTP → the public register route
// answers something other than 403.
func TestAPI_AccessTokenIsRefusedEverywhere(t *testing.T) {
	h, st, _ := newTestHandler(t)
	st.SaveCustomerConfig(&store.CustomerConfig{CustomerID: "c1", APIKey: "ckey", RetrievalPassword: "pass-phrase"})
	st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "HKEY"})
	for _, r := range apiRoutes {
		rr := do(h, r.Method, apiSample(r), store.APITokenPrefix+"abcdefghijklmnopqrstuvwxyz234567abcdefghijklmnopqrst", "{}")
		if rr.Code != http.StatusForbidden || !strings.Contains(rr.Body.String(), "access tokens are not accepted") {
			t.Errorf("%s %s with an access token: %d %q", r.Method, apiSample(r), rr.Code, strings.TrimSpace(rr.Body.String()))
		}
	}
}