package main

import (
	"context"
	"encoding/json"
	"errors"
	"strings"
	"testing"
)

// The machine's images, at 2026-10-04 12:00 (client's Now):
//
//	img1  store/web line, used by the container mesh-web
//	img2  postgres:16, used by the stopped container dev-db
//	web-old  store/web@sha256:old, older than img1: the previous, kept
//	web-older store/web, oldest: removed
//	app-new  store/app@sha256:cur: declared, not running
//	app-mid  local build tag app-build:abc AND store/app@sha256:mid: one image, two names, one line: previous
//	app-old  app-build:old: same line through the local name: removed
//	fresh    other:1, two days old: younger than the floor
//	gone     retired:1, no line in use: removed
const imagesInspect = `[
 {"Id":"sha256:img1","RepoTags":["store:5000/web/site:latest"],"RepoDigests":["store:5000/web/site@sha256:w1"],"Created":"2026-09-20T00:00:00Z","Size":100},
 {"Id":"sha256:img2","RepoTags":["postgres:16"],"RepoDigests":["postgres@sha256:pg"],"Created":"2026-01-01T00:00:00Z","Size":200},
 {"Id":"sha256:webold","RepoTags":[],"RepoDigests":["store:5000/web/site@sha256:w0"],"Created":"2026-09-10T00:00:00Z","Size":100},
 {"Id":"sha256:webolder","RepoTags":[],"RepoDigests":["store:5000/web/site@sha256:wm"],"Created":"2026-09-01T00:00:00Z","Size":100},
 {"Id":"sha256:appnew","RepoTags":[],"RepoDigests":["store:5000/app/server@sha256:cur"],"Created":"2026-09-25T00:00:00Z","Size":50},
 {"Id":"sha256:appmid","RepoTags":["app-build:abc"],"RepoDigests":["store:5000/app/server@sha256:mid"],"Created":"2026-09-20T00:00:00Z","Size":50},
 {"Id":"sha256:appold","RepoTags":["app-build:old"],"RepoDigests":[],"Created":"2026-09-01T00:00:00Z","Size":50},
 {"Id":"sha256:fresh","RepoTags":["other:1"],"RepoDigests":[],"Created":"2026-10-02T00:00:00Z","Size":10},
 {"Id":"sha256:gone","RepoTags":["retired:1"],"RepoDigests":[],"Created":"2026-08-01T00:00:00Z","Size":70}
]`

const ids = "sha256:img1\nsha256:img2\nsha256:webold\nsha256:webolder\nsha256:appnew\nsha256:appmid\nsha256:appold\nsha256:fresh\nsha256:gone\n"

func imagesMachine() *fake {
	f := machine().
		on("docker image ls --quiet --no-trunc", Ran{Stdout: ids}).
		on("docker image inspect", Ran{Stdout: imagesInspect}).
		on("docker image rm", Ran{Stdout: "Deleted"})
	return f
}

func declaring(t *testing.T, answer string) Asker {
	return func(key string, body any) (json.RawMessage, error) {
		if key != "seat:mesh-controller.images" {
			t.Errorf("asked %s", key)
		}
		if b, _ := body.(map[string]any); b["node"] != "laptop" {
			t.Errorf("asked for %v", body)
		}
		wrapped, _ := json.Marshal(map[string]any{"ok": true, "output": "", "answer": json.RawMessage(answer)})
		return wrapped, nil
	}
}

const declaredApp = `{"node":"laptop","sent_known":true,"images":[
 {"image":"store:5000/app/server@sha256:cur","resources":["app.server"],"in":["declaration"]},
 {"image":"docker.io/library/postgres@sha256:pg","resources":["db.server"],"in":["sent"]}]}`

func pruned(t *testing.T, out map[string]any) map[string]*PrunedImage {
	t.Helper()
	got := map[string]*PrunedImage{}
	for _, img := range out["images"].([]*PrunedImage) {
		got[img.ID] = img
	}
	return got
}

func has(why []string, w string) bool {
	for _, x := range why {
		if x == w {
			return true
		}
	}
	return false
}

func TestImagesAreKeptForEachReasonAndTheRestAreCandidates(t *testing.T) {
	f := imagesMachine()
	c := client(f, 1000)
	c.Node, c.Ask = "laptop", declaring(t, declaredApp)
	out, err := c.PruneImages(context.Background(), PruneImagesAsk{DryRun: true, OlderThanDays: 7, Limit: 100})
	if err != nil {
		t.Fatal(err)
	}
	got := pruned(t, out)
	want := map[string]string{
		"img1": keptUsed, "img2": keptUsed, "webold": keptPrevious, "appnew": keptDeclared,
		"appmid": keptPrevious, "fresh": keptYoung,
	}
	for id, w := range want {
		if !got[id].Kept || !has(got[id].Why, w) {
			t.Errorf("%s: kept %v why %v, want %s", id, got[id].Kept, got[id].Why, w)
		}
	}
	if !has(got["img2"].Why, keptDeclared) {
		t.Errorf("postgres named as docker.io/library/postgres@… was not matched: %v", got["img2"].Why)
	}
	for _, id := range []string{"webolder", "appold", "gone"} {
		if got[id].Kept {
			t.Errorf("%s kept: %v", id, got[id].Why)
		}
	}
	if got["appmid"].Line != got["appold"].Line || got["appmid"].Line != got["appnew"].Line {
		t.Errorf("an image with two names did not join its lines: %q %q %q", got["appmid"].Line, got["appold"].Line, got["appnew"].Line)
	}
	if out["bytes_candidate"].(int64) != 220 {
		t.Errorf("bytes %v", out["bytes_candidate"])
	}
	if f.ran("docker image rm") {
		t.Fatal("a dry run removed an image")
	}
}

func TestARealRunRemovesByNameNeverForced(t *testing.T) {
	f := imagesMachine()
	c := client(f, 1000)
	c.Node, c.Ask = "laptop", declaring(t, declaredApp)
	out, err := c.PruneImages(context.Background(), PruneImagesAsk{DryRun: false, Why: "disk", OlderThanDays: 7, Limit: 100})
	if err != nil {
		t.Fatal(err)
	}
	if n := len(out["removed"].([]string)); n != 3 {
		t.Errorf("removed %v", out["removed"])
	}
	for _, call := range f.calls {
		line := strings.Join(call.args, " ")
		if strings.HasPrefix(line, "image rm") {
			if strings.Contains(line, "-f") || strings.Contains(line, "--force") {
				t.Errorf("forced: %s", line)
			}
			if strings.Contains(line, "sha256:img1") || strings.Contains(line, "web/site@sha256:w0") {
				t.Errorf("removed a kept image: %s", line)
			}
		}
	}
}

func TestARefusalIsReportedAndTheRestGoOn(t *testing.T) {
	f := machine().
		on("docker image ls --quiet --no-trunc", Ran{Stdout: ids}).
		on("docker image inspect", Ran{Stdout: imagesInspect}).
		on("docker image rm retired:1", Ran{Status: 1, Stderr: "conflict: unable to remove repository reference"}).
		on("docker image rm", Ran{Stdout: "Deleted"})
	c := client(f, 1000)
	c.Node, c.Ask = "laptop", declaring(t, declaredApp)
	out, err := c.PruneImages(context.Background(), PruneImagesAsk{DryRun: false, Why: "disk", OlderThanDays: 7})
	if err != nil {
		t.Fatal(err)
	}
	if len(out["refused"].([]map[string]string)) != 1 || len(out["removed"].([]string)) != 2 {
		t.Errorf("removed %v refused %v", out["removed"], out["refused"])
	}
}

func TestNoAnswerFromTheControllerRemovesNothing(t *testing.T) {
	for name, c := range map[string]*Client{
		"error": {Node: "laptop", Ask: func(string, any) (json.RawMessage, error) { return nil, errors.New("no responders") }},
		"refused": {Node: "laptop", Ask: func(string, any) (json.RawMessage, error) {
			return json.RawMessage(`{"ok":false,"output":"no such machine"}`), nil
		}},
		"no node": {Ask: declaring(t, declaredApp)},
	} {
		f := imagesMachine()
		cl := client(f, 1000)
		cl.Node, cl.Ask = c.Node, c.Ask
		out, err := cl.PruneImages(context.Background(), PruneImagesAsk{DryRun: false, Why: "disk", OlderThanDays: 7})
		if err != nil {
			t.Fatal(name, err)
		}
		if f.ran("docker image rm") {
			t.Errorf("%s: removed without knowing the declaration", name)
		}
		if out["declaration_known"] != false || out["counts"].(map[string]int)["candidates"] != 0 {
			t.Errorf("%s: %v", name, out["counts"])
		}
	}
}

func TestARealRunWithoutWhyIsRefused(t *testing.T) {
	f := imagesMachine()
	c := client(f, 1000)
	c.Node, c.Ask = "laptop", declaring(t, declaredApp)
	if _, err := c.PruneImages(context.Background(), PruneImagesAsk{DryRun: false, OlderThanDays: 7}); err == nil {
		t.Fatal("a real run without why was accepted")
	}
	if len(f.calls) != 0 {
		t.Fatal("something was asked of the runtime before refusing")
	}
	for _, tool := range tools(c) {
		if tool.Name == "docker_prune_images" {
			if _, err := tool.Run(map[string]any{"dry_run": false}); err == nil {
				t.Fatal("the tool accepted a real run without why")
			}
		}
	}
}

func TestReferencesAreNormalisedAsTheRuntimeReportsThem(t *testing.T) {
	for in, want := range map[string]string{
		"docker.io/library/redis@sha256:x": "redis@sha256:x",
		"redis":                            "redis:latest",
		"store:5000/a/b":                   "store:5000/a/b:latest",
		"store:5000/a/b:1":                 "store:5000/a/b:1",
		"ghcr.io/x/y@sha256:z":             "ghcr.io/x/y@sha256:z",
	} {
		if got := normalRef(in); got != want {
			t.Errorf("%s: %s, want %s", in, got, want)
		}
	}
	if repositoryOf("store:5000/a/b:1") != "store:5000/a/b" || repositoryOf("store:5000/a/b@sha256:z") != "store:5000/a/b" {
		t.Error("repository")
	}
}