package plan

import (
	"os"
	"strings"
	"testing"
	"time"

	"github.com/tegwick/fluid-telegram/internal/spec"
	"github.com/tegwick/fluid-telegram/internal/state"
)

type fake struct {
	botExists bool
	rights    map[int64][]string
	usernames map[int64]string
}

func (f fake) BotExists(string) (bool, error) { return f.botExists, nil }
func (f fake) ChannelAdminRights(id int64) ([]string, error) {
	if r, ok := f.rights[id]; ok {
		return r, nil
	}
	return []string{spec.PostMessages}, nil
}
func (f fake) ChannelUsername(id int64) (string, error) { return f.usernames[id], nil }

func sp() *spec.Presence {
	return &spec.Presence{
		SchemaVersion: "0.1", Campaign: "hall-of-helix", Interface: "i",
		Bot: spec.Bot{Name: "HelixForge", UsernamePreference: []string{"HelixForgeBot"}},
		Channels: map[string]spec.Channel{
			spec.Test: {Title: "t", Visibility: spec.Private},
			spec.Live: {Title: "p", Visibility: spec.Public, UsernamePreference: []string{"hallofhelix"}},
		},
	}
}

func find(p *Plan, kind Kind, target string) *Action {
	for i := range p.Actions {
		if p.Actions[i].Kind == kind && p.Actions[i].Target == target {
			return &p.Actions[i]
		}
	}
	return nil
}

// First run: everything is created, and the public channel is blocked because
// no rendering has been checked yet.
func TestFirstRunCreatesAndBlocksPublic(t *testing.T) {
	p, err := Compute("", sp(), "sha256:x", &state.Resolved{}, fake{})
	if err != nil {
		t.Fatal(err)
	}
	if find(p, Attempt, "bot") == nil {
		t.Error("expected a bot registration attempt")
	}
	if find(p, Create, "channel.test") == nil {
		t.Error("expected the test channel to be created")
	}
	if find(p, Defer, "channel.public") == nil {
		t.Error("public channel must be deferred until the test channel is verified")
	}
	// A first run is not an error state. The bot and the test channel must still
	// be creatable while the public channel waits.
	if p.Blocked() {
		t.Errorf("a first run should not block:\n%s", p.Render())
	}
	if p.Empty() {
		t.Error("a first run has work to do")
	}
}

func provisioned(withTestPublication bool) *state.Resolved {
	rs := &state.Resolved{
		Campaign: "hall-of-helix",
		Bot:      state.Bot{Username: "HelixForgeBot", ID: 42},
		Channels: map[string]state.Channel{
			spec.Test: {ChatID: -100, AdminRights: []string{spec.PostMessages}},
			spec.Live: {ChatID: -200, Username: "hallofhelix", AdminRights: []string{spec.PostMessages}},
		},
	}
	if withTestPublication {
		now := time.Now()
		c := rs.Channels[spec.Test]
		c.TestPublicationAt = &now
		rs.Channels[spec.Test] = c
	}
	return rs
}

// Converged: a second run over an unchanged spec proposes nothing but the
// idempotent profile reassertion.
func TestConvergedRunIsQuiet(t *testing.T) {
	f := fake{botExists: true, usernames: map[int64]string{-200: "hallofhelix"}}
	p, err := Compute("", sp(), "sha256:x", provisioned(true), f)
	if err != nil {
		t.Fatal(err)
	}
	if p.Blocked() {
		t.Fatalf("converged plan should not block:\n%s", p.Render())
	}
	for _, a := range p.Actions {
		if a.Kind == Create || a.Kind == Attempt {
			t.Errorf("unexpected %s of %s on a converged presence", a.Kind, a.Target)
		}
	}
}

// Widened rights are a refusal, not a repair.
func TestWidenedRightsBlock(t *testing.T) {
	f := fake{botExists: true, usernames: map[int64]string{-200: "hallofhelix"},
		rights: map[int64][]string{-200: {spec.PostMessages, "can_delete_messages"}}}
	p, _ := Compute("", sp(), "sha256:x", provisioned(true), f)
	a := find(p, Block, "channel.public.admin")
	if a == nil {
		t.Fatalf("widened rights must block:\n%s", p.Render())
	}
	if !strings.Contains(a.Why, "not allowed to exercise") {
		t.Errorf("block should explain why: %q", a.Why)
	}
}

// A demoted bot blocks too -- losing the right is as much a drift as gaining one.
func TestLostRightsBlock(t *testing.T) {
	f := fake{botExists: true, usernames: map[int64]string{-200: "hallofhelix"},
		rights: map[int64][]string{-100: {}}}
	p, _ := Compute("", sp(), "sha256:x", provisioned(true), f)
	if find(p, Block, "channel.test.admin") == nil {
		t.Fatalf("a demoted bot must block:\n%s", p.Render())
	}
}

// A username that changed underneath us is not reconciled.
func TestUsernameTakeoverBlocks(t *testing.T) {
	f := fake{botExists: true, usernames: map[int64]string{-200: "someoneelse"}}
	p, _ := Compute("", sp(), "sha256:x", provisioned(true), f)
	if find(p, Block, "channel.public.username") == nil {
		t.Fatalf("a changed username must block:\n%s", p.Render())
	}
}

// A missing bot blocks rather than being re-created, which would orphan the
// token already in OpenBao.
func TestMissingBotBlocks(t *testing.T) {
	f := fake{botExists: false}
	p, _ := Compute("", sp(), "sha256:x", provisioned(true), f)
	if find(p, Block, "bot") == nil {
		t.Fatalf("an unreachable bot must block:\n%s", p.Render())
	}
}

// Removing a channel from the spec warns; it never deletes.
func TestRemovedChannelWarnsNeverDeletes(t *testing.T) {
	s := sp()
	delete(s.Channels, spec.Live)
	f := fake{botExists: true}
	p, _ := Compute("", s, "sha256:x", provisioned(true), f)
	a := find(p, Warn, "channel.public")
	if a == nil {
		t.Fatalf("expected a warning:\n%s", p.Render())
	}
	for _, act := range p.Actions {
		if strings.Contains(strings.ToLower(act.Detail), "delete") && act.Kind != Warn {
			t.Errorf("plan proposed a deletion: %+v", act)
		}
	}
}

// Pointing a state file at a different campaign is a mistake, not a rename.
func TestCampaignMismatchBlocks(t *testing.T) {
	rs := provisioned(true)
	rs.Campaign = "some-other-campaign"
	p, _ := Compute("", sp(), "sha256:x", rs, fake{botExists: true})
	if find(p, Block, "campaign") == nil {
		t.Fatalf("campaign mismatch must block:\n%s", p.Render())
	}
}

func TestRenderShowsRefusalsFirst(t *testing.T) {
	rs := provisioned(true)
	rs.Campaign = "some-other-campaign"
	p, _ := Compute("", sp(), "sha256:x", rs, fake{botExists: true})
	out := p.Render()
	if !strings.Contains(out, "nothing will be applied") {
		t.Errorf("a blocked plan should say so:\n%s", out)
	}
	if !strings.Contains(out, "BLOCK") {
		t.Error("expected a BLOCK in the render")
	}
}

// A deferral is not a block: the two must not collapse into each other, or a
// first run can never apply anything.
func TestDeferIsNotBlock(t *testing.T) {
	p, _ := Compute("", sp(), "sha256:x", &state.Resolved{}, fake{})
	if p.Blocked() {
		t.Fatal("a deferral must not block the plan")
	}
	f := fake{botExists: true, usernames: map[int64]string{-200: "someoneelse"}}
	p2, _ := Compute("", sp(), "sha256:x", provisioned(true), f)
	if !p2.Blocked() {
		t.Fatal("real drift must block")
	}
}

// Once the test channel is verified, the public channel stops being deferred.
func TestVerifiedTestChannelReleasesPublic(t *testing.T) {
	f := fake{botExists: true, usernames: map[int64]string{-200: "hallofhelix"}}
	p, _ := Compute("", sp(), "sha256:x", provisioned(true), f)
	if find(p, Defer, "channel.public") != nil {
		t.Errorf("public should no longer be deferred:\n%s", p.Render())
	}
}

// The plan must not promise an action apply will silently skip. The avatar is
// the live case: /setuserpic needs an upload that is not implemented, so the
// plan defers it with an explanation instead of claiming a create.
func TestAvatarIsDeferredNotPromised(t *testing.T) {
	s := sp()
	s.Bot.Avatar = "does-not-exist.png"
	p, _ := Compute("", s, "sha256:x", &state.Resolved{}, fake{})

	if find(p, Create, "bot.avatar") != nil {
		t.Fatal("plan promised an avatar it could not load")
	}
	a := find(p, Defer, "bot.avatar")
	if a == nil {
		t.Fatalf("a missing avatar should defer, not block:\n%s", p.Render())
	}
	if !strings.Contains(a.Why, "not there") {
		t.Errorf("deferral should say the file is missing: %q", a.Why)
	}
	if p.Blocked() {
		t.Error("a missing avatar must not stop everything else applying")
	}
}

// A real image is planned as a create, content-addressed.
func TestAvatarPlannedFromRealFile(t *testing.T) {
	const real = "../../../pr-hall-of-helix/presence/telegram.yaml"
	if _, err := os.Stat(real); err != nil {
		t.Skip("campaign repo not in this checkout")
	}
	s := sp()
	s.Bot.Avatar = "assets/helix-forge.png"
	p, _ := Compute(real, s, "sha256:x", &state.Resolved{}, fake{})
	if p.Avatar == nil {
		t.Fatalf("expected a loaded avatar:\n%s", p.Render())
	}
	if find(p, Create, "bot.avatar") == nil {
		t.Fatalf("expected an avatar create:\n%s", p.Render())
	}

	// Once recorded, the same file must not be re-sent: the digest is what
	// decides, so an unchanged picture is silence.
	rs := &state.Resolved{Bot: state.Bot{AvatarDigest: p.Avatar.Digest}}
	p2, _ := Compute(real, s, "sha256:x", rs, fake{})
	if find(p2, Create, "bot.avatar") != nil || find(p2, Update, "bot.avatar") != nil {
		t.Errorf("an unchanged avatar should propose nothing:\n%s", p2.Render())
	}

	// A different digest means the file was replaced, which is an update.
	rs.Bot.AvatarDigest = "sha256:something-else"
	p3, _ := Compute(real, s, "sha256:x", rs, fake{})
	if find(p3, Update, "bot.avatar") == nil {
		t.Errorf("a replaced avatar should update:\n%s", p3.Render())
	}
}