package cabana_test

import (
	"context"
	"errors"
	"fmt"
	"io/fs"
	"net/http"
	"strings"
	"sync"
	"testing"
	"time"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/cabana"
	"git.golem15.com/golem15/summercms/modules/lagoon"
	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/party"
	"gorm.io/gorm"
)

// Unit tests (plan 05 of phase 19.3) for pact.ReorderAfterSave (D-11): the
// hook runs inside the reorder transaction after the new order is written,
// receives the partition, and its error rolls the reorder back. They reuse
// the partitioned flat acme.shelf fixture of catalog_smoke_test.go.

// hookShelfPlugin is acme.shelf with a pins controller that implements
// pact.ReorderAfterSave through hook.
type hookShelfPlugin struct {
	hook func(ctx context.Context, partition *uint64) error
}

func (hookShelfPlugin) ID() string                   { return "acme.shelf" }
func (hookShelfPlugin) Requires() []string           { return nil }
func (hookShelfPlugin) Register(*backpack.App) error { return nil }
func (hookShelfPlugin) Boot(*backpack.App) error     { return nil }
func (hookShelfPlugin) AdminFS() fs.FS               { return shelfFS }
func (p hookShelfPlugin) AdminControllers() []pact.AdminController {
	return []pact.AdminController{hookedPins{hook: p.hook}}
}
func (hookShelfPlugin) Permissions() []pact.Permission {
	return []pact.Permission{{Code: "acme.shelf.access", Roles: []string{"developer"}}}
}

// hookedPins is shelfPins with the reorder hook.
type hookedPins struct {
	shelfPins
	hook func(ctx context.Context, partition *uint64) error
}

func (h hookedPins) ReorderAfterSave(ctx context.Context, partition *uint64) error {
	return h.hook(ctx, partition)
}

var _ pact.ReorderAfterSave = hookedPins{}

// shelfHookEnv is a logged-in admin over plugin with fresh acme.shelf
// tables, two shelves and three pins (A=1 and B=2 on top, X=7 on low).
type shelfHookEnv struct {
	*conformEnv
	top, low shelfShelf
	a, b, x  uint
}

func newShelfHookEnv(t *testing.T, plugin party.Plugin) *shelfHookEnv {
	t.Helper()
	gdb := adminGorm(t)
	models := []any{&shelfPin{}, &shelfShelf{}}
	if err := gdb.Migrator().DropTable(models...); err != nil {
		t.Fatal(err)
	}
	if err := gdb.AutoMigrate(models...); err != nil {
		t.Fatal(err)
	}
	login := fmt.Sprintf("shelf-hook-%d", time.Now().UnixNano())
	insertAdmin(t, gdb, login, login+"@example.test", adminTestPassword, true, false)
	h, err := paymentsAssemble(t, gdb, []party.Plugin{plugin})
	if err != nil {
		t.Fatal(err)
	}
	env := &shelfHookEnv{conformEnv: &conformEnv{h: h, db: gdb, login: login}, top: shelfShelf{Title: "Top"}, low: shelfShelf{Title: "Low"}}
	if rec := env.send(t, http.MethodPost, "/auth/login", map[string]string{"login": login, "password": adminTestPassword}, false); rec.Code != http.StatusOK {
		t.Fatalf("login status=%d body=%s", rec.Code, rec.Body.String())
	}
	for _, s := range []*shelfShelf{&env.top, &env.low} {
		if err := gdb.Create(s).Error; err != nil {
			t.Fatal(err)
		}
	}
	pins := []shelfPin{{Name: "A", ShelfID: &env.top.ID, SortOrder: 1}, {Name: "B", ShelfID: &env.top.ID, SortOrder: 2}, {Name: "X", ShelfID: &env.low.ID, SortOrder: 7}}
	for i := range pins {
		if err := gdb.Create(&pins[i]).Error; err != nil {
			t.Fatal(err)
		}
	}
	env.a, env.b, env.x = pins[0].ID, pins[1].ID, pins[2].ID
	return env
}

// swap posts B=1, A=2 for the top shelf and returns the status and body.
func (e *shelfHookEnv) swap(t *testing.T) (int, string) {
	t.Helper()
	rec := e.send(t, http.MethodPost, "/acme/shelf/pins/reorder", map[string]any{
		"partition": e.top.ID,
		"nodes": []map[string]any{
			{"id": e.b, "parent_id": nil, "sort_order": 1},
			{"id": e.a, "parent_id": nil, "sort_order": 2},
		},
	}, true)
	return rec.Code, rec.Body.String()
}

// sorts reads the sort values of every pin through db.
func sorts(t *testing.T, db *gorm.DB) map[uint]int {
	t.Helper()
	var all []shelfPin
	if err := db.Order("id").Find(&all).Error; err != nil {
		t.Fatal(err)
	}
	out := map[uint]int{}
	for _, p := range all {
		out[p.ID] = p.SortOrder
	}
	return out
}

func TestReorderHookRunsInTx(t *testing.T) {
	var (
		mu          sync.Mutex
		calls       int
		gotPart     *uint64
		inTx        map[uint]int
		outside     map[uint]int
		hasTx       bool
		afterCommit map[uint]int
	)
	var env *shelfHookEnv
	env = newShelfHookEnv(t, hookShelfPlugin{hook: func(ctx context.Context, partition *uint64) error {
		mu.Lock()
		defer mu.Unlock()
		calls++
		gotPart = partition
		tx, ok := cabana.TxFromContext(ctx)
		hasTx = ok
		if !ok {
			return errors.New("no transaction in the hook context")
		}
		inTx = sorts(t, tx.WithContext(ctx))
		// Another connection still sees the committed order.
		outside = sorts(t, env.db)
		lagoon.AfterCommit(ctx, tx, func(ctx context.Context, db *gorm.DB) {
			mu.Lock()
			defer mu.Unlock()
			afterCommit = sorts(t, db.WithContext(ctx))
		})
		return nil
	}})

	code, body := env.swap(t)
	if code != http.StatusOK {
		t.Fatalf("POST status=%d body=%s", code, body)
	}
	mu.Lock()
	defer mu.Unlock()
	if calls != 1 || !hasTx {
		t.Fatalf("hook calls=%d tx=%t", calls, hasTx)
	}
	if gotPart == nil || *gotPart != uint64(env.top.ID) {
		t.Fatalf("partition = %v, want %d", gotPart, env.top.ID)
	}
	if inTx[env.b] != 1 || inTx[env.a] != 2 || inTx[env.x] != 7 {
		t.Fatalf("hook saw %v through the transaction, want the new order", inTx)
	}
	if outside[env.a] != 1 || outside[env.b] != 2 {
		t.Fatalf("outside the transaction %v, want the old order before commit", outside)
	}
	if afterCommit == nil || afterCommit[env.b] != 1 || afterCommit[env.a] != 2 {
		t.Fatalf("AfterCommit work saw %v, want the committed new order", afterCommit)
	}
	if got := sorts(t, env.db); got[env.b] != 1 || got[env.a] != 2 || got[env.x] != 7 {
		t.Fatalf("stored = %v", got)
	}
}

func TestReorderHookErrorRollsBack(t *testing.T) {
	for _, tc := range []struct {
		name   string
		err    error
		status int
	}{
		{"plain error", errors.New("purge registry unavailable"), http.StatusInternalServerError},
		{"validation error", &cabana.ValidationError{Details: map[string]any{"nodes": []string{"Refused."}}}, http.StatusUnprocessableEntity},
		{"forbidden", &cabana.ForbiddenError{Message: "Locked."}, http.StatusForbidden},
	} {
		t.Run(tc.name, func(t *testing.T) {
			var afterCommitRan bool
			env := newShelfHookEnv(t, hookShelfPlugin{hook: func(ctx context.Context, _ *uint64) error {
				tx, _ := cabana.TxFromContext(ctx)
				lagoon.AfterCommit(ctx, tx, func(context.Context, *gorm.DB) { afterCommitRan = true })
				return tc.err
			}})
			before := sorts(t, env.db)
			code, body := env.swap(t)
			if code != tc.status {
				t.Fatalf("status=%d want %d body=%s", code, tc.status, body)
			}
			if after := sorts(t, env.db); fmt.Sprint(after) != fmt.Sprint(before) {
				t.Fatalf("sort values changed: before %v after %v", before, after)
			}
			if afterCommitRan {
				t.Fatal("AfterCommit work ran after a rolled-back reorder")
			}
			if tc.status == http.StatusInternalServerError && (strings.Contains(body, "purge registry") || !strings.Contains(body, `"error"`)) {
				t.Fatalf("500 body = %s", body)
			}
		})
	}
}

func TestReorderWithoutHookUnchanged(t *testing.T) {
	plain := newShelfHookEnv(t, shelfPlugin{})
	code, plainBody := plain.swap(t)
	if code != http.StatusOK {
		t.Fatalf("POST status=%d body=%s", code, plainBody)
	}
	if got := sorts(t, plain.db); got[plain.b] != 1 || got[plain.a] != 2 || got[plain.x] != 7 {
		t.Fatalf("stored = %v", got)
	}

	// A hook that does nothing answers the same tree.
	hooked := newShelfHookEnv(t, hookShelfPlugin{hook: func(context.Context, *uint64) error { return nil }})
	code, hookedBody := hooked.swap(t)
	if code != http.StatusOK {
		t.Fatalf("hooked POST status=%d body=%s", code, hookedBody)
	}
	if plainBody != hookedBody {
		t.Fatalf("answers differ:\nwithout hook %s\nwith hook    %s", plainBody, hookedBody)
	}
}