package bridge

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

	"git.novox.be/novox/mesh-sdk/go/delivery"
)

const head = "0123456789abcdef0123456789abcdef01234567"

// updated is the body of gitea.pull.updated as mesh-catalog modules/gitea/trunk.ts:233-250 (announcementOf) writes
// it: owner, repo, number, base_sha, title, body, base, head (the branch), head_sha, clone_url, html_url, paths,
// paths_truncated, removed, module_dirs, module_dirs_said, merge_check, merge_check_said.
func updated(extra map[string]any) []byte {
	m := map[string]any{
		"owner": "novox", "repo": "mesh-delivery", "number": 12,
		"base_sha": "ffffffffffffffffffffffffffffffffffffffff", "title": "A change", "body": "text", "base": "main",
		"head": "feat/x", "head_sha": head, "clone_url": "https://forge.example/novox/mesh-delivery.git",
		"html_url": "https://forge.example/novox/mesh-delivery/pulls/12",
		"paths":    []string{"modules/a/x.go"}, "paths_truncated": false, "removed": []string{},
		"module_dirs": []string{"modules/a"}, "module_dirs_said": true,
		"merge_check": true, "merge_check_said": true,
	}
	for k, v := range extra {
		if v == nil {
			delete(m, k)
		} else {
			m[k] = v
		}
	}
	b, _ := json.Marshal(m)
	return b
}

// closed is the body of gitea.pull.closed as mesh-catalog modules/gitea/index.ts:127-128 writes it: owner, repo,
// number, title, head, head_sha, base, html_url.
func closed() []byte {
	b, _ := json.Marshal(map[string]any{"owner": "novox", "repo": "mesh-delivery", "number": 12, "title": "A change",
		"head": "feat/x", "head_sha": head, "base": "main", "html_url": "https://forge.example/novox/mesh-delivery/pulls/12"})
	return b
}

const updatedSubject = "mesh.mod.gitea.event.pull.updated"
const closedSubject = "mesh.mod.gitea.event.pull.closed"

func TestUpdatedBecomesAPullMessage(t *testing.T) { // 1235/AC2 (the conversion; the bus is the integration test)
	msg, err := Convert(updatedSubject, updated(nil), nil)
	if err != nil {
		t.Fatal(err)
	}
	if msg.Event != "forge.novox.mesh-delivery.pull" {
		t.Errorf("event = %q", msg.Event)
	}
	f, err := delivery.DecodeForge(msg.Data)
	if err != nil {
		t.Fatal(err)
	}
	want := delivery.Forge{V: delivery.Version, Kind: delivery.ForgePull, Repository: "novox/mesh-delivery", Branch: "feat/x", Number: 12,
		Head: head, Action: delivery.PullUpdated, Dirs: []string{"modules/a"}, DirsKnown: true}
	if !delivery.SameForge(f, want) {
		t.Errorf("message = %+v, want %+v", f, want)
	}
}

func TestDirsNotSaidAreNotKnown(t *testing.T) { // 1235/AC3
	msg, err := Convert(updatedSubject, updated(map[string]any{"module_dirs": nil, "module_dirs_said": nil}), nil)
	if err != nil {
		t.Fatal(err)
	}
	f, _ := delivery.DecodeForge(msg.Data)
	if f.DirsKnown || len(f.Dirs) != 0 {
		t.Errorf("dirs = %v known = %v, want not known", f.Dirs, f.DirsKnown)
	}
	// Said and empty is known and empty, not unknown.
	msg, err = Convert(updatedSubject, updated(map[string]any{"module_dirs": []string{}, "module_dirs_said": true}), nil)
	if err != nil {
		t.Fatal(err)
	}
	f, _ = delivery.DecodeForge(msg.Data)
	if !f.DirsKnown || len(f.Dirs) != 0 {
		t.Errorf("dirs = %v known = %v, want known and empty", f.Dirs, f.DirsKnown)
	}
	// Dirs listed without the forge saying it could read them are not trusted.
	msg, err = Convert(updatedSubject, updated(map[string]any{"module_dirs_said": nil}), nil)
	if err != nil {
		t.Fatal(err)
	}
	if f, _ = delivery.DecodeForge(msg.Data); f.DirsKnown || len(f.Dirs) != 0 {
		t.Errorf("dirs %v known %v without module_dirs_said", f.Dirs, f.DirsKnown)
	}
}

func TestClosedBecomesAClosedPullMessage(t *testing.T) { // 1235/AC4
	msg, err := Convert(closedSubject, closed(), nil)
	if err != nil {
		t.Fatal(err)
	}
	if msg.Event != "forge.novox.mesh-delivery.pull" {
		t.Errorf("event = %q", msg.Event)
	}
	f, err := delivery.DecodeForge(msg.Data)
	if err != nil {
		t.Fatal(err)
	}
	want := delivery.Forge{V: delivery.Version, Kind: delivery.ForgePull, Repository: "novox/mesh-delivery", Branch: "feat/x", Number: 12,
		Head: head, Action: delivery.PullClosed}
	if !delivery.SameForge(f, want) {
		t.Errorf("message = %+v, want %+v", f, want)
	}
}

func TestUnreadableEventsWriteNothing(t *testing.T) { // 1235/AC5
	for name, c := range map[string]struct {
		subject string
		data    []byte
		why     string
	}{
		"no owner":        {updatedSubject, updated(map[string]any{"owner": nil}), "owner"},
		"no repo":         {updatedSubject, updated(map[string]any{"repo": nil}), "repo"},
		"no number":       {updatedSubject, updated(map[string]any{"number": nil}), "number"},
		"number zero":     {updatedSubject, updated(map[string]any{"number": 0}), "number"},
		"short head":      {updatedSubject, updated(map[string]any{"head_sha": "abc123"}), "head"},
		"head not hex":    {updatedSubject, updated(map[string]any{"head_sha": strings.Repeat("g", 40)}), "head"},
		"upper-case head": {updatedSubject, updated(map[string]any{"head_sha": strings.ToUpper(head)}), "head"},
		"no branch":       {updatedSubject, updated(map[string]any{"head": nil}), "branch"},
		"not json":        {updatedSubject, []byte("{"), "json"},
		"closed no head":  {closedSubject, mustDrop(closed(), "head_sha"), "head"},
		"closed no repo":  {closedSubject, mustDrop(closed(), "repo"), "repo"},
	} {
		msg, err := Convert(c.subject, c.data, nil)
		if err == nil {
			t.Errorf("%s: a message %q was made", name, msg.Event)
			continue
		}
		if !errors.Is(err, ErrUnreadable) {
			t.Errorf("%s: error %v is not ErrUnreadable", name, err)
		}
		if !strings.Contains(err.Error(), c.why) || !strings.Contains(err.Error(), c.subject) {
			t.Errorf("%s: error %q names neither its subject nor %q", name, err, c.why)
		}
		if msg.Data != nil {
			t.Errorf("%s: data was made", name)
		}
	}
}

func mustDrop(body []byte, key string) []byte {
	var m map[string]any
	_ = json.Unmarshal(body, &m)
	delete(m, key)
	b, _ := json.Marshal(m)
	return b
}

func TestOtherSubjectsAreNotHandled(t *testing.T) { // 1235
	for _, s := range []string{"mesh.mod.gitea.event.something.else", "mesh.mod.other.event.pull.updated"} {
		if _, err := Convert(s, updated(nil), nil); !errors.Is(err, ErrNotHandled) {
			t.Errorf("%s: err = %v, want ErrNotHandled", s, err)
		}
	}
}

const merge = "89abcdef0123456789abcdef0123456789abcdef"

// mergedBody is gitea.pull.merged as mesh-catalog modules/gitea/index.ts:186-207 writes it.
func mergedBody(extra map[string]any) []byte {
	m := map[string]any{
		"owner": "novox", "repo": "mesh-delivery", "number": 12, "title": "A change", "body": "text",
		"head_sha": head, "head_checks": map[string]string{"mesh/merge-gate": "success"}, "head": "feat/x", "base": "main",
		"merge_commit_sha": merge, "merged_at": "2026-10-19T12:00:00Z", "clone_url": "https://forge.example/novox/mesh-delivery.git",
		"html_url": "https://forge.example/novox/mesh-delivery/pulls/12", "paths": []string{"modules/a/x.go"}, "paths_truncated": false,
		"removed": []string{}, "module_dirs": []string{"modules/a"}, "module_dirs_said": true,
	}
	for k, v := range extra {
		if v == nil {
			delete(m, k)
		} else {
			m[k] = v
		}
	}
	b, _ := json.Marshal(m)
	return b
}

const mergedSubject = "mesh.mod.gitea.event.pull.merged"

type call struct{ owner, repo, sha string }

// treesOf answers as gitea_commit_trees does (issue 1234/AC4: root, and the directory to tree hash, the root spelled "").
func treesOf(calls *[]call, root string, trees map[string]string, err error) Trees {
	return func(owner, repo, sha string) (string, map[string]string, error) {
		*calls = append(*calls, call{owner, repo, sha})
		return root, trees, err
	}
}

func TestMergeIntoMainBecomesAMergedMessage(t *testing.T) { // 1236/AC1
	var calls []call
	answer := map[string]string{"modules/a": "t1", "modules/b": "t2"}
	msg, err := Convert(mergedSubject, mergedBody(nil), treesOf(&calls, "r0", answer, nil))
	if err != nil {
		t.Fatal(err)
	}
	if msg.Event != "forge.novox.mesh-delivery.merged" {
		t.Errorf("event = %q", msg.Event)
	}
	f, err := delivery.DecodeForge(msg.Data)
	if err != nil {
		t.Fatal(err)
	}
	want := delivery.Forge{V: delivery.Version, Kind: delivery.ForgeMerged, Repository: "novox/mesh-delivery", Branch: "feat/x", Number: 12,
		Head: head, Merge: merge, Root: "r0", Trees: answer}
	if !delivery.SameForge(f, want) {
		t.Errorf("message = %+v, want %+v", f, want)
	}
	if len(calls) != 1 || calls[0] != (call{"novox", "mesh-delivery", merge}) {
		t.Errorf("the tool was called %v, want once with novox, mesh-delivery and the merge commit", calls)
	}
}

func TestMergeIntoAnotherBranchIsAClosedPull(t *testing.T) { // 1236/AC2
	var calls []call
	msg, err := Convert(mergedSubject, mergedBody(map[string]any{"base": "feat/y"}), treesOf(&calls, "r0", map[string]string{"a": "t"}, nil))
	if err != nil {
		t.Fatal(err)
	}
	f, err := delivery.DecodeForge(msg.Data)
	if err != nil {
		t.Fatal(err)
	}
	want := delivery.Forge{V: delivery.Version, Kind: delivery.ForgePull, Repository: "novox/mesh-delivery", Branch: "feat/x", Number: 12,
		Head: head, Action: delivery.PullClosed}
	if msg.Event != "forge.novox.mesh-delivery.pull" || !delivery.SameForge(f, want) {
		t.Errorf("event %q message %+v, want a closed pull message", msg.Event, f)
	}
	if len(calls) != 0 {
		t.Errorf("the tool was called for a merge into another branch: %v", calls)
	}
}

func TestTreesRefusedWritesNothingAndSaysWhy(t *testing.T) { // 1236/AC3 (the conversion; the delay is in main_test)
	var calls []call
	msg, err := Convert(mergedSubject, mergedBody(nil), treesOf(&calls, "", nil, errors.New("the listing for novox/mesh-delivery was cut")))
	if !errors.Is(err, ErrRetry) || msg.Data != nil {
		t.Fatalf("err = %v data = %s, want ErrRetry and no message", err, msg.Data)
	}
	for _, w := range []string{"novox/mesh-delivery", merge, "the listing for novox/mesh-delivery was cut"} {
		if !strings.Contains(err.Error(), w) {
			t.Errorf("error %q does not name %q", err, w)
		}
	}
}

func TestNoModuleJSONAnywhereWritesNoMergedMessage(t *testing.T) { // 1236 (notes: a repository with no module.json)
	var calls []call
	msg, err := Convert(mergedSubject, mergedBody(nil), treesOf(&calls, "r0", map[string]string{}, nil))
	if !errors.Is(err, ErrNoModules) || msg.Data != nil {
		t.Errorf("err = %v data = %s", err, msg.Data)
	}
}

func TestMergedWithoutAMergeCommitIsUnreadable(t *testing.T) { // 1236
	var calls []call
	_, err := Convert(mergedSubject, mergedBody(map[string]any{"merge_commit_sha": "abc"}), treesOf(&calls, "r0", map[string]string{"a": "t"}, nil))
	if !errors.Is(err, ErrUnreadable) || len(calls) != 0 {
		t.Errorf("err = %v calls = %v", err, calls)
	}
}

// openAnswer is gitea_open_pulls's answer as mesh-catalog modules/gitea/client.ts:369-381 builds each entry
// (owner, repo, number, base, head, head_sha, html_url, required, statuses, checks, labels) inside {pulls}.
func openAnswer(pulls ...map[string]any) []byte {
	b, _ := json.Marshal(map[string]any{"pulls": pulls})
	return b
}

func openEntry(repo string, number int, base, branch, sha string) map[string]any {
	return map[string]any{"owner": "novox", "repo": repo, "number": number, "base": base, "head": branch, "head_sha": sha,
		"html_url": "https://forge.example/x", "required": []string{"mesh/merge-gate"}, "statuses": []string{}, "checks": map[string]string{}, "labels": []string{}}
}

func TestOpenPullsAreUpdatedPullMessagesWithUnknownDirs(t *testing.T) { // 1237/AC1
	h2 := strings.Repeat("a", 40)
	msgs, skipped, err := OpenPulls(openAnswer(openEntry("mesh-delivery", 12, "main", "feat/x", head), openEntry("mesh-catalog", 300, "main", "feat/x", h2)))
	if err != nil || len(skipped) != 0 || len(msgs) != 2 {
		t.Fatalf("msgs %d skipped %v err %v", len(msgs), skipped, err)
	}
	for i, want := range []delivery.Forge{
		{V: delivery.Version, Kind: delivery.ForgePull, Repository: "novox/mesh-delivery", Branch: "feat/x", Number: 12, Head: head, Action: delivery.PullUpdated},
		{V: delivery.Version, Kind: delivery.ForgePull, Repository: "novox/mesh-catalog", Branch: "feat/x", Number: 300, Head: h2, Action: delivery.PullUpdated},
	} {
		f, err := delivery.DecodeForge(msgs[i].Data)
		if err != nil || !delivery.SameForge(f, want) {
			t.Errorf("message %d = %+v err %v, want %+v", i, f, err, want)
		}
		if f.DirsKnown {
			t.Errorf("message %d says its directories are known", i)
		}
	}
	if msgs[0].Event != "forge.novox.mesh-delivery.pull" || msgs[1].Event != "forge.novox.mesh-catalog.pull" {
		t.Errorf("events %q %q", msgs[0].Event, msgs[1].Event)
	}
}

func TestOpenPullIntoAnotherBranchGetsNoMessage(t *testing.T) { // 1237/AC4
	msgs, skipped, err := OpenPulls(openAnswer(openEntry("mesh-delivery", 12, "feat/y", "feat/x", head)))
	if err != nil || len(msgs) != 0 || len(skipped) != 0 {
		t.Errorf("msgs %d skipped %v err %v, want none", len(msgs), skipped, err)
	}
}

func TestOpenPullsUnreadableEntryIsNamedAndTheRestGo(t *testing.T) { // 1237
	msgs, skipped, err := OpenPulls(openAnswer(openEntry("a", 1, "main", "b", "short"), openEntry("mesh-delivery", 12, "main", "feat/x", head)))
	if err != nil || len(msgs) != 1 || len(skipped) != 1 || !strings.Contains(skipped[0], "novox/a#1") {
		t.Errorf("msgs %d skipped %v err %v", len(msgs), skipped, err)
	}
	for _, bad := range []string{`{"pulls":null}`, `{}`, `[]`, `x`} {
		if _, _, err := OpenPulls([]byte(bad)); err == nil {
			t.Errorf("%s was taken as an answer", bad)
		}
	}
}

func TestOpenMessageNamesEveryOpenPullIntoTheTrunk(t *testing.T) { // 1279/AC6
	h2 := strings.Repeat("a", 40)
	answer := openAnswer(openEntry("mesh-delivery", 12, "main", "feat/x", head), openEntry("mesh-catalog", 300, "main", "feat/x", h2),
		openEntry("mesh-catalog", 301, "feat/y", "feat/z", h2), openEntry("a", 1, "main", "b", "short"))
	m, err := OpenMessage(answer)
	if err != nil || m.Event != "forge.open" {
		t.Fatalf("message %+v err %v", m, err)
	}
	f, err := delivery.DecodeForge(m.Data)
	// Every one into the trunk, whether its head reads or not (it is open); none into another branch; in a fixed order.
	want := []delivery.OpenPull{{Repository: "novox/a", Number: 1}, {Repository: "novox/mesh-catalog", Number: 300}, {Repository: "novox/mesh-delivery", Number: 12}}
	if err != nil || f.Kind != delivery.ForgeOpen || len(f.Open) != 3 || f.Open[0] != want[0] || f.Open[1] != want[1] || f.Open[2] != want[2] {
		t.Errorf("open message = %+v err %v, want %v", f, err, want)
	}
	// Nothing open is a message too: the indexer then drops every candidate.
	m, err = OpenMessage([]byte(`{"pulls":[]}`))
	if f, derr := delivery.DecodeForge(m.Data); err != nil || derr != nil || f.Kind != delivery.ForgeOpen || len(f.Open) != 0 {
		t.Errorf("empty answer: %+v %v %v", f, err, derr)
	}
	for _, bad := range []string{`{"pulls":null}`, `{}`, `x`} {
		if _, err := OpenMessage([]byte(bad)); err == nil {
			t.Errorf("%s was taken as an answer", bad)
		}
	}
}

func TestTrackSaysWhichHeadOfWhichPullRequestWasWritten(t *testing.T) { // 1279/AC6
	pullMsg := func(action string) delivery.Forge {
		return delivery.Forge{Kind: delivery.ForgePull, Repository: "novox/mesh-delivery", Branch: "feat/x", Number: 12, Head: head, Action: action}
	}
	for _, a := range []string{delivery.PullOpened, delivery.PullUpdated} {
		if key, h, ok := Track(pullMsg(a)); key != "novox.mesh-delivery.12" || h != head || !ok {
			t.Errorf("%s: Track = %q %q %v, want the head kept under a bucket key", a, key, h, ok)
		}
	}
	// A closed pull request and a merged one are no longer kept: their key goes.
	if key, h, ok := Track(pullMsg(delivery.PullClosed)); key != "novox.mesh-delivery.12" || h != "" || !ok {
		t.Errorf("closed: Track = %q %q %v", key, h, ok)
	}
	merged := delivery.Forge{Kind: delivery.ForgeMerged, Repository: "novox/mesh-delivery", Branch: "feat/x", Number: 12, Head: head, Merge: "m", Root: "r", Trees: map[string]string{"": "t"}}
	if key, h, ok := Track(merged); key != "novox.mesh-delivery.12" || h != "" || !ok {
		t.Errorf("merged: Track = %q %q %v", key, h, ok)
	}
	// The open message and the rest hold no head.
	if _, _, ok := Track(delivery.Forge{Kind: delivery.ForgeOpen}); ok {
		t.Error("an open message was tracked")
	}
}