package surf

import (
	"context"
	"database/sql"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/compass"
	"git.golem15.com/golem15/summercms/modules/lagoon"
	"git.golem15.com/golem15/summercms/modules/lagoon/attach"
	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/party"
	_ "github.com/jackc/pgx/v5/stdlib"
	"github.com/testcontainers/testcontainers-go"
	"github.com/testcontainers/testcontainers-go/modules/postgres"
	"gocloud.dev/blob"
	"gocloud.dev/blob/memblob"
	"gorm.io/gorm"
)

// uploadsConfig is an http config with the body limits and the given
// storage.uploads keys set.
func uploadsConfig(t *testing.T, keys map[string]any) *compass.Config {
	t.Helper()
	cfg := writeHTTPConfig(t, "body_limits:\n  default_bytes: 1024\n  upload_bytes: 1024\n")
	for k, v := range keys {
		if err := cfg.Set(k, v); err != nil {
			t.Fatal(err)
		}
	}
	return cfg
}

// uploadsPathPlugin registers GET <path> under the uploads prefix.
type uploadsPathPlugin struct{ path string }

func (uploadsPathPlugin) ID() string                   { return "acme.media" }
func (uploadsPathPlugin) Requires() []string           { return nil }
func (uploadsPathPlugin) Register(*backpack.App) error { return nil }
func (uploadsPathPlugin) Boot(*backpack.App) error     { return nil }
func (p uploadsPathPlugin) Routes(r pact.Router) error {
	r.Get(p.path, func(w http.ResponseWriter, _ *http.Request) { _, _ = w.Write([]byte("plugin")) })
	return nil
}

// uploadsGorm starts a Postgres container with the framework migrations
// (system_files). An unavailable Docker daemon fails the test.
func uploadsGorm(t *testing.T) *gorm.DB {
	t.Helper()
	if testing.Short() {
		t.Skip("requires testcontainers postgres")
	}
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
	t.Cleanup(cancel)
	ctr, err := postgres.Run(ctx,
		"postgres:16-alpine",
		postgres.WithDatabase("uploads"),
		postgres.WithUsername("uploads"),
		postgres.WithPassword("uploads"),
		postgres.BasicWaitStrategies(),
	)
	if err != nil {
		t.Fatalf("postgres: %v", err)
	}
	t.Cleanup(func() { _ = testcontainers.TerminateContainer(ctr) })
	dsn, err := ctr.ConnectionString(ctx, "sslmode=disable")
	if err != nil {
		t.Fatal(err)
	}
	db, err := sql.Open("pgx", dsn)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = db.Close() })
	if err := db.PingContext(ctx); err != nil {
		t.Fatal(err)
	}
	gdb, err := lagoon.Use(ctx, db)
	if err != nil {
		t.Fatal(err)
	}
	if err := lagoon.Migrate(gdb, nil); err != nil {
		t.Fatal(err)
	}
	return gdb
}

type uploadsResponse struct {
	code   int
	header http.Header
	body   string
}

func uploadsDo(h http.Handler, method, target string) uploadsResponse {
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(method, target, nil))
	return uploadsResponse{code: rec.Code, header: rec.Header(), body: rec.Body.String()}
}

// uploadsRoutes returns the routes summercms.surf owns.
func uploadsRoutes(t *testing.T, app *backpack.App, plugins []party.Plugin) []RouteInfo {
	t.Helper()
	rt, err := BuildRouter(app, plugins)
	if err != nil {
		t.Fatal(err)
	}
	var out []RouteInfo
	for _, info := range rt.Routes() {
		if info.PluginID == uploadsPluginID {
			out = append(out, info)
		}
	}
	return out
}

const (
	uploadsPublicDisk  = "abc123xyz.png"
	uploadsPrivateDisk = "def456uvw.png"
	uploadsOrphanDisk  = "ghi789rst.png"
	uploadsPublicBody  = "public-png-bytes"
)

// TestUploadsMount: with storage.uploads.serve off (or absent) no route is
// registered; on, GET <prefix>/{path...} serves a public blob with its
// content type and nosniff, answers HEAD without a body, and 404s a
// private row, a missing row, traversal paths and an unpublished bucket or
// database. A custom prefix is honoured, and a plugin route at or under
// the prefix fails BuildRouter.
func TestUploadsMount(t *testing.T) {
	publicPath := "/storage/uploads/abc/123/xyz/" + uploadsPublicDisk

	t.Run("off registers nothing", func(t *testing.T) {
		for _, keys := range []map[string]any{nil, {"storage.uploads.serve": false}} {
			app := backpack.New(uploadsConfig(t, keys))
			if routes := uploadsRoutes(t, app, nil); len(routes) != 0 {
				t.Fatalf("keys %v: uploads routes %v", keys, routes)
			}
			h, err := Assemble(app, nil)
			if err != nil {
				t.Fatal(err)
			}
			if r := uploadsDo(h, http.MethodGet, publicPath); r.code != http.StatusNotFound {
				t.Fatalf("keys %v: GET %s = %d, want 404", keys, publicPath, r.code)
			}
		}
	})

	t.Run("on registers one GET route", func(t *testing.T) {
		app := backpack.New(uploadsConfig(t, map[string]any{"storage.uploads.serve": true}))
		routes := uploadsRoutes(t, app, nil)
		if len(routes) != 1 || routes[0].Method != http.MethodGet || routes[0].Pattern != "/storage/uploads/{path...}" || !routes[0].Raw {
			t.Fatalf("uploads routes = %+v", routes)
		}
	})

	t.Run("a plugin route at or under the prefix fails BuildRouter", func(t *testing.T) {
		for _, path := range []string{"/storage/uploads/{path...}", "/storage/uploads/avatars/{id}", "/storage/uploads"} {
			app := backpack.New(uploadsConfig(t, map[string]any{"storage.uploads.serve": true}))
			_, err := BuildRouter(app, []party.Plugin{uploadsPathPlugin{path: path}})
			if err == nil || !strings.Contains(err.Error(), "storage.uploads") {
				t.Fatalf("plugin route %s: err = %v, want a refusal naming storage.uploads", path, err)
			}
		}
		// A sibling path and the same path with the key off are fine.
		app := backpack.New(uploadsConfig(t, map[string]any{"storage.uploads.serve": true}))
		if _, err := BuildRouter(app, []party.Plugin{uploadsPathPlugin{path: "/storage/uploadsx/{id}"}}); err != nil {
			t.Fatalf("sibling path: %v", err)
		}
		app = backpack.New(uploadsConfig(t, nil))
		if _, err := BuildRouter(app, []party.Plugin{uploadsPathPlugin{path: "/storage/uploads/avatars/{id}"}}); err != nil {
			t.Fatalf("key off: %v", err)
		}
	})

	t.Run("nothing published answers 404", func(t *testing.T) {
		app := backpack.New(uploadsConfig(t, map[string]any{"storage.uploads.serve": true}))
		h, err := Assemble(app, nil)
		if err != nil {
			t.Fatal(err)
		}
		r := uploadsDo(h, http.MethodGet, publicPath)
		if r.code != http.StatusNotFound || r.header.Get("X-Content-Type-Options") != "nosniff" {
			t.Fatalf("no bucket, no database: %d nosniff=%q", r.code, r.header.Get("X-Content-Type-Options"))
		}
		bucket := memblob.OpenBucket(nil)
		t.Cleanup(func() { _ = bucket.Close() })
		if err := bucket.WriteAll(t.Context(), attach.BlobKey(uploadsPublicDisk), []byte(uploadsPublicBody), nil); err != nil {
			t.Fatal(err)
		}
		if err := app.Publish(bucket); err != nil {
			t.Fatal(err)
		}
		if r := uploadsDo(h, http.MethodGet, publicPath); r.code != http.StatusNotFound {
			t.Fatalf("bucket without a database: %d, want 404", r.code)
		}
	})

	gdb := uploadsGorm(t)
	ctx := t.Context()
	bucket := memblob.OpenBucket(nil)
	t.Cleanup(func() { _ = bucket.Close() })
	pub, priv := true, false
	for _, f := range []attach.File{
		{DiskName: uploadsPublicDisk, FileName: "cover.png", FileSize: 1, ContentType: "image/png", IsPublic: &pub},
		{DiskName: uploadsPrivateDisk, FileName: "secret.png", FileSize: 1, ContentType: "image/png", IsPublic: &priv},
	} {
		if err := gdb.Create(&f).Error; err != nil {
			t.Fatal(err)
		}
	}
	for disk, body := range map[string]string{
		uploadsPublicDisk:  uploadsPublicBody,
		uploadsPrivateDisk: "private-png-bytes",
		uploadsOrphanDisk:  "orphan-png-bytes",
	} {
		if err := bucket.WriteAll(ctx, attach.BlobKey(disk), []byte(body), &blob.WriterOptions{ContentType: "image/png"}); err != nil {
			t.Fatal(err)
		}
	}

	t.Run("database without a bucket answers 404", func(t *testing.T) {
		app := backpack.New(uploadsConfig(t, map[string]any{"storage.uploads.serve": true}))
		if err := app.Publish(gdb); err != nil {
			t.Fatal(err)
		}
		h, err := Assemble(app, nil)
		if err != nil {
			t.Fatal(err)
		}
		if r := uploadsDo(h, http.MethodGet, publicPath); r.code != http.StatusNotFound {
			t.Fatalf("database without a bucket: %d, want 404", r.code)
		}
	})

	serving := func(t *testing.T, prefix string) http.Handler {
		t.Helper()
		keys := map[string]any{"storage.uploads.serve": true}
		if prefix != "" {
			keys["storage.uploads.public_path_prefix"] = prefix
		}
		app := backpack.New(uploadsConfig(t, keys))
		if err := app.Publish(gdb); err != nil {
			t.Fatal(err)
		}
		if err := app.Publish(bucket); err != nil {
			t.Fatal(err)
		}
		h, err := Assemble(app, nil)
		if err != nil {
			t.Fatal(err)
		}
		return h
	}

	t.Run("serves public blobs and refuses the rest", func(t *testing.T) {
		h := serving(t, "")
		r := uploadsDo(h, http.MethodGet, publicPath)
		if r.code != http.StatusOK || r.body != uploadsPublicBody {
			t.Fatalf("GET %s = %d %q", publicPath, r.code, r.body)
		}
		if ct := r.header.Get("Content-Type"); ct != "image/png" {
			t.Fatalf("Content-Type = %q, want image/png", ct)
		}
		if got := r.header.Get("X-Content-Type-Options"); got != "nosniff" {
			t.Fatalf("X-Content-Type-Options = %q, want nosniff", got)
		}
		head := uploadsDo(h, http.MethodHead, publicPath)
		if head.code != http.StatusOK || head.body != "" || head.header.Get("Content-Type") != "image/png" || head.header.Get("X-Content-Type-Options") != "nosniff" {
			t.Fatalf("HEAD %s = %d %q %v", publicPath, head.code, head.body, head.header)
		}
		for _, target := range []string{
			"/storage/uploads/def/456/uvw/" + uploadsPrivateDisk, // is_public false
			"/storage/uploads/ghi/789/rst/" + uploadsOrphanDisk,  // blob without a row
			"/storage/uploads/zzz/999/yyy/zzz999yyy.png",         // neither
			"/storage/uploads/abc/123/" + uploadsPublicDisk,      // partition too short
			"/storage/uploads/def/456/xyz/" + uploadsPublicDisk,  // wrong partition
			"/storage/uploads/abc/123/xyz/..%2f..%2f..%2fsecret", // encoded traversal
			"/storage/uploads/abc/123/xyz/%2e%2e%2f" + uploadsPrivateDisk,
			"/storage/uploads/abc/123/xyz/..%5c" + uploadsPrivateDisk, // encoded backslash
		} {
			r := uploadsDo(h, http.MethodGet, target)
			if r.code != http.StatusNotFound || r.header.Get("X-Content-Type-Options") != "nosniff" {
				t.Fatalf("GET %s = %d nosniff=%q, want 404 with nosniff", target, r.code, r.header.Get("X-Content-Type-Options"))
			}
			if strings.Contains(r.body, "png-bytes") {
				t.Fatalf("GET %s leaked a blob: %q", target, r.body)
			}
		}
		// A raw dot-dot path never reaches the handler: ServeMux answers it
		// with a redirect to the cleaned path, which is then served or
		// refused by the same rules.
		for target, want := range map[string]int{
			"/storage/uploads/abc/123/../../def/456/uvw/" + uploadsPrivateDisk: http.StatusNotFound,
			"/storage/uploads/../../../etc/passwd":                             http.StatusNotFound,
		} {
			r := uploadsDo(h, http.MethodGet, target)
			if strings.Contains(r.body, "png-bytes") {
				t.Fatalf("GET %s leaked a blob: %d %q", target, r.code, r.body)
			}
			if r.code == http.StatusMovedPermanently || r.code == http.StatusTemporaryRedirect || r.code == http.StatusPermanentRedirect {
				loc := r.header.Get("Location")
				if strings.Contains(loc, "..") {
					t.Fatalf("GET %s redirects to %q", target, loc)
				}
				if got := uploadsDo(h, http.MethodGet, loc); got.code != want {
					t.Fatalf("GET %s -> %s = %d, want %d", target, loc, got.code, want)
				}
				continue
			}
			if r.code != want {
				t.Fatalf("GET %s = %d, want %d or a redirect", target, r.code, want)
			}
		}
	})

	t.Run("a custom prefix is honoured", func(t *testing.T) {
		h := serving(t, "/media/files/")
		custom := "/media/files/abc/123/xyz/" + uploadsPublicDisk
		if r := uploadsDo(h, http.MethodGet, custom); r.code != http.StatusOK || r.body != uploadsPublicBody || r.header.Get("X-Content-Type-Options") != "nosniff" {
			t.Fatalf("GET %s = %d %q", custom, r.code, r.body)
		}
		if r := uploadsDo(h, http.MethodGet, publicPath); r.code != http.StatusNotFound {
			t.Fatalf("GET %s under the default prefix = %d, want 404", publicPath, r.code)
		}
	})
}