package handler

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"codeberg.org/VARASYS/ZDDC/zddc/internal/archive"
	"codeberg.org/VARASYS/ZDDC/zddc/internal/config"
	"codeberg.org/VARASYS/ZDDC/zddc/internal/listing"
	"codeberg.org/VARASYS/ZDDC/zddc/internal/zddc"
)

// archiveTestRoot lays down a two-project tree so listings exercise scope and
// ACL cascading. ACLs are written per-test in the helper that calls this.
//
//	<root>/
//	  ProjectA/
//	    2025-01-01_T1 (IFR) - Title/100_~A (IFR) - Title.pdf
//	    2025-01-01_T1 (IFR) - Title/100_A  (IFC) - Title.pdf
//	    2025-02-01_T2 (RTN) - Comments/100_~A+C1 (RTN) - Comments.pdf
//	  ProjectB/
//	    2025-01-01_T3 (IFR) - Title/200_0 (IFR) - Other.pdf
func archiveTestRoot(t *testing.T) (string, *archive.Index) {
	t.Helper()
	root := t.TempDir()

	mk := func(rel string) {
		path := filepath.Join(root, filepath.FromSlash(rel))
		if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
			t.Fatalf("mkdir: %v", err)
		}
		if err := os.WriteFile(path, []byte("x"), 0o644); err != nil {
			t.Fatalf("write %s: %v", path, err)
		}
	}

	mk("ProjectA/2025-01-01_T1 (IFR) - Title/100_~A (IFR) - Title.pdf")
	mk("ProjectA/2025-01-01_T1 (IFR) - Title/100_A (IFC) - Title.pdf")
	mk("ProjectA/2025-02-01_T2 (RTN) - Comments/100_~A+C1 (RTN) - Comments.pdf")
	mk("ProjectB/2025-01-01_T3 (IFR) - Title/200_0 (IFR) - Other.pdf")

	idx, err := archive.BuildIndex(root)
	if err != nil {
		t.Fatalf("BuildIndex: %v", err)
	}
	return root, idx
}

// writeZddc writes a .zddc YAML at <root>/<rel>/.zddc and clears the
// per-directory policy cache so a previous test's permissive .zddc doesn't
// bleed into this one.
func writeZddc(t *testing.T, root, rel, body string) {
	t.Helper()
	dir := filepath.Join(root, filepath.FromSlash(rel))
	if err := os.MkdirAll(dir, 0o755); err != nil {
		t.Fatalf("mkdir %s: %v", dir, err)
	}
	if err := os.WriteFile(filepath.Join(dir, ".zddc"), []byte(body), 0o644); err != nil {
		t.Fatalf("write .zddc: %v", err)
	}
	zddc.InvalidateCache(dir)
}

func archiveCfg(root string) config.Config {
	return config.Config{Root: root, EmailHeader: "X-Auth-Request-Email", IndexPath: ".archive"}
}

func callArchive(t *testing.T, cfg config.Config, idx *archive.Index, email, contextPath, filename string) *httptest.ResponseRecorder {
	t.Helper()
	urlPath := contextPath
	if !strings.HasSuffix(urlPath, "/") {
		urlPath += "/"
	}
	urlPath += ".archive/" + filename
	req := httptest.NewRequest(http.MethodGet, urlPath, nil)
	req = req.WithContext(context.WithValue(req.Context(), EmailKey, email))
	rec := httptest.NewRecorder()
	ServeArchive(cfg, idx, rec, req, contextPath, filename)
	return rec
}

func decodeListing(t *testing.T, body []byte) []listing.FileInfo {
	t.Helper()
	var out []listing.FileInfo
	if err := json.Unmarshal(body, &out); err != nil {
		t.Fatalf("invalid JSON: %v\n%s", err, body)
	}
	return out
}

func names(entries []listing.FileInfo) []string {
	out := make([]string, 0, len(entries))
	for _, e := range entries {
		out = append(out, e.Name)
	}
	return out
}

func contains(xs []string, x string) bool {
	for _, v := range xs {
		if v == x {
			return true
		}
	}
	return false
}

// .archive at any depth serves the SAME global index (modulo ACL). Only the
// URL prefix on the entries differs, so relative ../.archive/ links resolve
// to a working server endpoint no matter which folder the source page sits
// in.
func TestServeArchive_ListingIsGlobalAtEveryDepth(t *testing.T) {
	root, idx := archiveTestRoot(t)
	writeZddc(t, root, ".", `acl:
  allow: ["*"]
`)
	cfg := archiveCfg(root)
	const email = "alice@example.com"

	cases := []struct {
		name        string
		contextPath string
		urlPrefix   string
	}{
		{"root", "/", "/.archive/"},
		{"project depth", "/ProjectA", "/ProjectA/.archive/"},
		{"unrelated project depth", "/ProjectB", "/ProjectB/.archive/"},
	}

	wantNames := []string{"100.html", "100_A.html", "100_~A.html", "200.html", "200_0.html"}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			rec := callArchive(t, cfg, idx, email, c.contextPath, "")
			if rec.Code != http.StatusOK {
				t.Fatalf("status = %d, want 200; body = %s", rec.Code, rec.Body.String())
			}
			got := decodeListing(t, rec.Body.Bytes())
			gotNames := names(got)
			for _, want := range wantNames {
				if !contains(gotNames, want) {
					t.Errorf("missing %q at %s; got %v", want, c.contextPath, gotNames)
				}
			}
			for _, e := range got {
				if !strings.HasPrefix(e.URL, c.urlPrefix) {
					t.Errorf("entry %q URL = %q, want %s prefix", e.Name, e.URL, c.urlPrefix)
				}
			}
		})
	}
}

// Listing endpoint is gated by the contextPath ACL: callers who can't reach
// the directory the .archive virtually sits in get 403 (the directory is
// known to exist; just not accessible).
func TestServeArchive_ListingDeniedByContextPathACL(t *testing.T) {
	root, idx := archiveTestRoot(t)
	writeZddc(t, root, ".", `acl:
  allow: ["alice@example.com"]
`)
	writeZddc(t, root, "ProjectA", `acl:
  deny: ["mallory@example.com"]
  allow: ["alice@example.com"]
`)
	cfg := archiveCfg(root)

	rec := callArchive(t, cfg, idx, "mallory@example.com", "/ProjectA", "")
	if rec.Code != http.StatusForbidden {
		t.Errorf("denied caller got status %d, want 403; body = %s", rec.Code, rec.Body.String())
	}

	rec = callArchive(t, cfg, idx, "alice@example.com", "/ProjectA", "")
	if rec.Code != http.StatusOK {
		t.Errorf("allowed caller got status %d, want 200; body = %s", rec.Code, rec.Body.String())
	}
}

// Listing entries are filtered per-target by ACL: a caller denied at a
// subtree sees no entries from it — even when querying /.archive/ at the
// root where they ARE allowed. Excluding a user from a subdir requires an
// explicit deny there (the cascade is "first explicit match wins, bottom-
// up", so a child allow list doesn't narrow a parent's allow:["*"]).
func TestServeArchive_ListingFiltersEntriesByPerTargetACL(t *testing.T) {
	root, idx := archiveTestRoot(t)
	writeZddc(t, root, ".", `acl:
  allow: ["*"]
`)
	writeZddc(t, root, "ProjectB", `acl:
  deny: ["alice@example.com"]
`)
	cfg := archiveCfg(root)

	rec := callArchive(t, cfg, idx, "alice@example.com", "/", "")
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body = %s", rec.Code, rec.Body.String())
	}
	gotNames := names(decodeListing(t, rec.Body.Bytes()))

	for _, want := range []string{"100.html", "100_A.html", "100_~A.html"} {
		if !contains(gotNames, want) {
			t.Errorf("alice missing accessible entry %q; got %v", want, gotNames)
		}
	}
	for _, hidden := range []string{"200.html", "200_0.html"} {
		if contains(gotNames, hidden) {
			t.Errorf("alice should not see ACL-blocked entry %q; got %v", hidden, gotNames)
		}
	}

	rec = callArchive(t, cfg, idx, "bob@example.com", "/", "")
	gotNames = names(decodeListing(t, rec.Body.Bytes()))
	if !contains(gotNames, "200.html") {
		t.Errorf("bob should see ProjectB entry 200.html; got %v", gotNames)
	}
}

// Direct redirect requests for a tracking number whose target the caller
// can't read return 404 (not 403, not 302) — the file's existence must not
// leak across the ACL boundary.
func TestServeArchive_ResolveACLDeniedReturns404(t *testing.T) {
	root, idx := archiveTestRoot(t)
	writeZddc(t, root, ".", `acl:
  allow: ["*"]
`)
	writeZddc(t, root, "ProjectB", `acl:
  deny: ["alice@example.com"]
`)
	cfg := archiveCfg(root)

	rec := callArchive(t, cfg, idx, "alice@example.com", "/", "200.html")
	if rec.Code != http.StatusNotFound {
		t.Errorf("alice → 200.html: status %d, want 404 (target ACL-denied)", rec.Code)
	}

	for _, fn := range []string{"100.html", "100_A.html", "100_~A.html", "100_~A+C1.html"} {
		rec := callArchive(t, cfg, idx, "alice@example.com", "/", fn)
		if rec.Code != http.StatusFound {
			t.Errorf("alice → %s: status %d, want 302; body = %s", fn, rec.Code, rec.Body.String())
		}
	}

	rec = callArchive(t, cfg, idx, "bob@example.com", "/", "200.html")
	if rec.Code != http.StatusFound {
		t.Errorf("bob → 200.html: status %d, want 302", rec.Code)
	}
}

// Cascade direction sanity check: a denial at the subtree wins over an
// allow at the parent, AND a target-level allow can rescue a user the
// parent didn't mention. Both directions of cascade must be exercised so
// future refactors of the per-target ACL helper can't silently break one.
func TestServeArchive_CascadeDirectionsBothEnforced(t *testing.T) {
	root, idx := archiveTestRoot(t)
	// Root: deny default — only bob is on the list. ProjectA: explicitly
	// allow alice. So alice is rescued at the leaf, mallory stays out
	// everywhere, bob stays in everywhere.
	writeZddc(t, root, ".", `acl:
  allow: ["bob@example.com"]
`)
	writeZddc(t, root, "ProjectA", `acl:
  allow: ["alice@example.com"]
`)
	cfg := archiveCfg(root)

	cases := []struct {
		email      string
		filename   string
		wantStatus int
		why        string
	}{
		{"bob@example.com", "100.html", http.StatusFound, "bob allowed at root → reaches ProjectA target"},
		{"bob@example.com", "200.html", http.StatusFound, "bob allowed at root → reaches ProjectB target"},
		{"alice@example.com", "100.html", http.StatusFound, "alice rescued by ProjectA allow"},
		{"alice@example.com", "200.html", http.StatusNotFound, "alice not in ProjectB chain → 404"},
		// mallory is denied EVERYWHERE — including the /ProjectA contextPath
		// — so she never reaches per-target evaluation; the contextPath
		// gate returns 403. (404 leak-prevention only kicks in once the
		// contextPath itself is reachable.)
		{"mallory@example.com", "100.html", http.StatusForbidden, "mallory blocked at contextPath"},
	}
	for _, c := range cases {
		t.Run(c.email+"_"+c.filename, func(t *testing.T) {
			// Use ProjectA as contextPath: alice is rescued there (so she
			// passes the gate and we get to per-target ACL on the ProjectB
			// resolve), and bob+mallory's behavior is governed by the root
			// rules.
			rec := callArchive(t, cfg, idx, c.email, "/ProjectA", c.filename)
			if rec.Code != c.wantStatus {
				t.Errorf("%s → %s: status %d, want %d (%s)", c.email, c.filename, rec.Code, c.wantStatus, c.why)
			}
		})
	}
}

// Resolved redirect Location header must be the absolute path to the actual
// file under cfg.Root, regardless of which contextPath the caller used to
// reach .archive. So /ProjectA/.archive/100.html and /.archive/100.html
// both 302 to the same file.
func TestServeArchive_ResolveLocationIsAbsoluteAndStableAcrossDepth(t *testing.T) {
	root, idx := archiveTestRoot(t)
	writeZddc(t, root, ".", `acl:
  allow: ["*"]
`)
	cfg := archiveCfg(root)

	wantLocPrefix := "/ProjectA/2025-01-01_T1 (IFR) - Title/100_A"
	for _, ctx := range []string{"/", "/ProjectA", "/ProjectB"} {
		rec := callArchive(t, cfg, idx, "alice@example.com", ctx, "100.html")
		if rec.Code != http.StatusFound {
			t.Errorf("ctx=%s status=%d body=%s", ctx, rec.Code, rec.Body.String())
			continue
		}
		loc := rec.Header().Get("Location")
		if !strings.HasPrefix(loc, wantLocPrefix) {
			t.Errorf("ctx=%s Location=%q, want prefix %q", ctx, loc, wantLocPrefix)
		}
	}
}

// Default-deny: as soon as ANY .zddc exists in the chain, an unmatched
// caller is denied. Verify this applies to listing entries too — a target
// in a directory with a restrictive .zddc is not surfaced to outsiders even
// though the file exists.
func TestServeArchive_DefaultDenyOnceZddcExists(t *testing.T) {
	root, idx := archiveTestRoot(t)
	// Root .zddc allows alice only. No "*" — so anyone else is default-denied.
	writeZddc(t, root, ".", `acl:
  allow: ["alice@example.com"]
`)
	cfg := archiveCfg(root)

	// alice sees everything she's allowed to.
	rec := callArchive(t, cfg, idx, "alice@example.com", "/", "")
	if rec.Code != http.StatusOK {
		t.Fatalf("alice listing: status %d, want 200", rec.Code)
	}
	if len(decodeListing(t, rec.Body.Bytes())) == 0 {
		t.Errorf("alice listing was empty, want entries")
	}

	// Charlie isn't on any list → default-deny at root → 403 even for the listing.
	rec = callArchive(t, cfg, idx, "charlie@example.com", "/", "")
	if rec.Code != http.StatusForbidden {
		t.Errorf("charlie listing: status %d, want 403", rec.Code)
	}

	// Direct resolve also denied (404 to avoid leak).
	rec = callArchive(t, cfg, idx, "charlie@example.com", "/", "100.html")
	// contextPath ACL fires first: at root, charlie is denied → 403.
	if rec.Code != http.StatusForbidden {
		t.Errorf("charlie resolve: status %d, want 403 (denied at contextPath)", rec.Code)
	}
}

// Empty email never matches — even an `allow: ["*"]` policy denies it,
// which is the existing zddc package contract. .archive must honor it.
func TestServeArchive_EmptyEmailDeniedEvenWithStarAllow(t *testing.T) {
	root, idx := archiveTestRoot(t)
	writeZddc(t, root, ".", `acl:
  allow: ["*@example.com"]
`)
	cfg := archiveCfg(root)

	rec := callArchive(t, cfg, idx, "", "/", "")
	if rec.Code != http.StatusForbidden {
		t.Errorf("anonymous listing: status %d, want 403", rec.Code)
	}
}