package party

import (
	"io/fs"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"testing/fstest"

	"git.golem15.com/golem15/summercms/backpack"
	"git.golem15.com/golem15/summercms/compass"
)

type tracePlugin struct {
	id  string
	req []string
	log *[]string
}

func (p *tracePlugin) ID() string         { return p.id }
func (p *tracePlugin) Requires() []string { return p.req }

func (p *tracePlugin) Register(*backpack.App) error {
	*p.log = append(*p.log, p.id+":register")
	return nil
}

func (p *tracePlugin) Boot(*backpack.App) error {
	*p.log = append(*p.log, p.id+":boot")
	return nil
}

type configPlugin struct {
	id   string
	fsys fs.FS
	got  *int
}

func (p *configPlugin) ID() string         { return p.id }
func (p *configPlugin) Requires() []string { return nil }
func (p *configPlugin) ConfigFS() fs.FS    { return p.fsys }

func (p *configPlugin) Register(app *backpack.App) error {
	if app != nil && app.Config != nil {
		*p.got = app.Config.Int("golem15.hello.posts_per_page")
	}
	return nil
}

func (p *configPlugin) Boot(*backpack.App) error { return nil }

func TestActivateMergesHasConfigBeforeRegister(t *testing.T) {
	dir := t.TempDir()
	if err := os.WriteFile(filepath.Join(dir, "app.yaml"), []byte("name: app\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	cfg, err := compass.Load(dir)
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	var got int
	p := &configPlugin{
		id:  "golem15.hello",
		got: &got,
		fsys: fstest.MapFS{
			"config/config.yaml": {Data: []byte("posts_per_page: 10\n")},
		},
	}
	app := backpack.New(cfg)
	if _, err := activate([]Plugin{p}, app, []string{"golem15.hello"}); err != nil {
		t.Fatalf("activate: %v", err)
	}
	if got != 10 {
		t.Fatalf("posts_per_page during Register = %d, want 10 (HasConfig must merge before Register)", got)
	}
}

func TestActivateMissingRequiresNamesIDsAndSkipsBoot(t *testing.T) {
	var log []string
	p := &tracePlugin{id: "golem15.greeter", req: []string{"golem15.hello"}, log: &log}
	app := backpack.New(&compass.Config{})
	_, err := activate([]Plugin{p}, app, []string{"golem15.greeter"})
	if err == nil {
		t.Fatal("expected missing dependency error")
	}
	msg := err.Error()
	if !strings.Contains(msg, "golem15.greeter") || !strings.Contains(msg, "golem15.hello") {
		t.Fatalf("error %q should name both plugin IDs", msg)
	}
	if strings.Contains(strings.Join(log, ","), "boot") {
		t.Fatalf("Boot ran despite missing dependency: %v", log)
	}
}

func TestActivateCycleNamesIDsAndSkipsBoot(t *testing.T) {
	var log []string
	a := &tracePlugin{id: "golem15.a", req: []string{"golem15.b"}, log: &log}
	b := &tracePlugin{id: "golem15.b", req: []string{"golem15.a"}, log: &log}
	app := backpack.New(&compass.Config{})
	_, err := activate([]Plugin{a, b}, app, []string{"golem15.a", "golem15.b"})
	if err == nil {
		t.Fatal("expected cycle error")
	}
	msg := err.Error()
	if !strings.Contains(msg, "golem15.a") || !strings.Contains(msg, "golem15.b") {
		t.Fatalf("error %q should name cycle members", msg)
	}
	if strings.Contains(strings.Join(log, ","), "boot") || strings.Contains(strings.Join(log, ","), "register") {
		t.Fatalf("lifecycle ran despite cycle: %v", log)
	}
}

func TestActivateDuplicateIDRejected(t *testing.T) {
	var log []string
	a := &tracePlugin{id: "golem15.hello", log: &log}
	dup := &tracePlugin{id: "golem15.hello", log: &log}
	app := backpack.New(&compass.Config{})
	_, err := activate([]Plugin{a, dup}, app, []string{"golem15.hello"})
	if err == nil {
		t.Fatal("expected duplicate id error")
	}
	if !strings.Contains(err.Error(), "golem15.hello") {
		t.Fatalf("error %q should name the duplicate id", err)
	}
}

type bootProbe struct {
	id     string
	req    []string
	log    *[]string
	sawOpt *bool
	booted *[]string
}

func (p *bootProbe) ID() string         { return p.id }
func (p *bootProbe) Requires() []string { return p.req }

func (p *bootProbe) Register(*backpack.App) error {
	*p.log = append(*p.log, p.id+":register")
	return nil
}

func (p *bootProbe) Boot(app *backpack.App) error {
	if p.sawOpt != nil && p.id == "golem15.hello" {
		*p.sawOpt = app.HasPlugin("golem15.optional")
	}
	*p.log = append(*p.log, p.id+":boot")
	if p.booted != nil {
		*p.booted = append(*p.booted, p.id)
	}
	return nil
}

func TestActivateHasPluginSeesNotYetBootedPlugins(t *testing.T) {
	var log []string
	var saw bool
	hello := &bootProbe{id: "golem15.hello", log: &log, sawOpt: &saw}
	opt := &bootProbe{id: "golem15.optional", log: &log}
	app := backpack.New(&compass.Config{})
	if _, err := activate([]Plugin{opt, hello}, app, []string{"golem15.hello", "golem15.optional"}); err != nil {
		t.Fatalf("activate: %v", err)
	}
	if !saw {
		t.Fatal("HasPlugin(golem15.optional) was false during hello Boot; complete set must be visible before Boot")
	}
	want := []string{
		"golem15.hello:register",
		"golem15.optional:register",
		"golem15.hello:boot",
		"golem15.optional:boot",
	}
	if strings.Join(log, ",") != strings.Join(want, ",") {
		t.Fatalf("lifecycle = %v, want %v", log, want)
	}
}

func TestActivateIndependentPluginsKeepManifestOrder(t *testing.T) {
	var log []string
	a := &tracePlugin{id: "golem15.a", log: &log}
	b := &tracePlugin{id: "golem15.b", log: &log}
	c := &tracePlugin{id: "golem15.c", log: &log}
	app := backpack.New(&compass.Config{})
	got, err := activate([]Plugin{c, a, b}, app, []string{"golem15.c", "golem15.a", "golem15.b"})
	if err != nil {
		t.Fatalf("activate: %v", err)
	}
	if len(got) != 3 || got[0].ID() != "golem15.c" || got[1].ID() != "golem15.a" || got[2].ID() != "golem15.b" {
		t.Fatalf("order = %v", idsOf(got))
	}
}

func idsOf(plugins []Plugin) []string {
	out := make([]string, len(plugins))
	for i, p := range plugins {
		out[i] = p.ID()
	}
	return out
}

func TestActivateRunsAllRegisterBeforeAnyBoot(t *testing.T) {
	var log []string
	hello := &tracePlugin{id: "golem15.hello", log: &log}
	greeter := &tracePlugin{id: "golem15.greeter", req: []string{"golem15.hello"}, log: &log}
	app := backpack.New(&compass.Config{})

	got, err := activate([]Plugin{greeter, hello}, app, []string{"golem15.greeter", "golem15.hello"})
	if err != nil {
		t.Fatalf("activate: %v", err)
	}
	if len(got) != 2 {
		t.Fatalf("got %d plugins, want 2", len(got))
	}
	if got[0].ID() != "golem15.hello" || got[1].ID() != "golem15.greeter" {
		t.Fatalf("order = %s, %s", got[0].ID(), got[1].ID())
	}

	want := []string{
		"golem15.hello:register",
		"golem15.greeter:register",
		"golem15.hello:boot",
		"golem15.greeter:boot",
	}
	if strings.Join(log, ",") != strings.Join(want, ",") {
		t.Fatalf("lifecycle = %v, want %v", log, want)
	}
}