package changelog

import (
	"reflect"
	"strings"
	"testing"
	"time"

	"github.com/carlosframework/platform/internal/docsite"
)

type fakeGit struct {
	tags        []Tag
	firstParent map[string][]Commit // "from..to"
	ranges      map[string][]Commit
	tombstones  map[string]Tag // branch -> tip sha and date
	live        map[string]bool
	docs        map[string][]DocsChange
}

func (g *fakeGit) Tags() ([]Tag, error) { return g.tags, nil }
func (g *fakeGit) FirstParent(to string, exclude []string) ([]Commit, error) {
	return g.firstParent[strings.Join(exclude, ",")+".."+to], nil
}
func (g *fakeGit) Range(from, to string) ([]Commit, error) { return g.ranges[from+".."+to], nil }
func (g *fakeGit) Tombstone(b string) (string, time.Time, bool) {
	t, ok := g.tombstones[b]
	return t.SHA, t.Date, ok
}
func (g *fakeGit) LiveBranch(b string) bool { return g.live[b] }
func (g *fakeGit) DocsChanges(c Commit) ([]DocsChange, error) {
	return g.docs[c.SHA], nil
}

type fakeReleases map[string]string

func (f fakeReleases) Body(tag string) (string, bool, error) {
	b, ok := f[tag]
	return b, ok, nil
}

type fakeDiscussions struct {
	byID     map[int]Discussion
	byBranch map[string][]Discussion
	shows    int
}

func (f *fakeDiscussions) Show(id int) (*Discussion, error) {
	f.shows++
	d, ok := f.byID[id]
	if !ok {
		return nil, nil
	}
	return &d, nil
}
func (f *fakeDiscussions) ForBranch(b string) ([]Discussion, error) { return f.byBranch[b], nil }

var (
	t0 = time.Date(2026, 9, 1, 12, 0, 0, 0, time.UTC)
	t1 = time.Date(2026, 10, 5, 12, 0, 0, 0, time.UTC)
)

const cliPage = "# The CLI\n\n## Your apps\n\n### carlos db\n\ntext\n\n### carlos services\n\ntext\n"

func testSite(t *testing.T) *docsite.Site {
	t.Helper()
	cli := docsite.Parse("cli", cliPage)
	idx := docsite.Parse("index", "# CARLOS\n\nintro\n")
	return &docsite.Site{Index: idx, BySlug: map[string]*docsite.Page{"cli": cli, "index": idx}}
}

func fixture() (*fakeGit, fakeReleases, *fakeDiscussions) {
	squash := Commit{SHA: "s1", Parents: []string{"p0"}, AuthorName: "claude", AuthorEmail: "claude~paul@keymail.dev", Date: t1,
		Message: "deploy-credential: scoped (#229)\n\nSquashed from design-deploy-credential into main."}
	merge := Commit{SHA: "m1", Parents: []string{"s1", "b9"}, AuthorName: "GitHub", AuthorEmail: "noreply@github.com", Date: t1,
		Message: "Merge pull request #417 from carlosframework/availability-tab\n\nissue #5"}
	direct := Commit{SHA: "d1", Parents: []string{"m1"}, AuthorName: "Paul Campbell", AuthorEmail: "paul@tito.io", Date: t1,
		Message: "docs: a direct fix\n\nCo-Authored-By: Claude <noreply@anthropic.com>"}
	old := Commit{SHA: "o1", AuthorName: "Paul Campbell", AuthorEmail: "paul@tito.io", Date: t0, Message: "first (#5)"}
	g := &fakeGit{
		tags: []Tag{{Name: "v0.10.0", SHA: "d1", Date: t1}, {Name: "v0.9.0", SHA: "o1", Date: t0}},
		firstParent: map[string][]Commit{
			"..v0.9.0":        {old},
			"v0.9.0..v0.10.0": {direct, merge, squash},
		},
		ranges: map[string][]Commit{
			"p0..tomb": {
				{SHA: "c2", AuthorName: "codex", AuthorEmail: "codex~paul@keymail.dev", Date: t1, Message: "more, discussion 230"},
				{SHA: "c1", AuthorName: "claude", AuthorEmail: "claude~paul@keymail.dev", Date: t1, Message: "start"},
			},
			"s1..b9": {{SHA: "b9", AuthorName: "Bill Horsman", AuthorEmail: "bill@keymail.dev", Date: t1, Message: "availability"}},
		},
		tombstones: map[string]Tag{"design-deploy-credential": {SHA: "tomb", Date: t1.Add(-time.Minute)}},
		docs: map[string][]DocsChange{
			"s1": {{Page: "cli", Body: cliPage, Added: []int{11}}},
			"d1": {{Page: "cli", Body: "# The CLI\n\n### carlos gone\n\nx\n", Added: []int{5}}, {Page: "index", Body: "# CARLOS\n\nintro\n", Added: []int{3}}},
		},
	}
	rel := fakeReleases{
		"v0.10.0": "carlos v0.10.0 (platform d1, 2026-10-05)\n\n- **CI can deploy.** `carlos services create --role deploy`.\n- **Other.** text\n",
		"v0.9.0":  "First release.\n",
	}
	disc := &fakeDiscussions{
		byID: map[int]Discussion{
			229: {ID: 229, Title: "CI cannot promote", State: "closed", Created: t1.Add(-48 * time.Hour).Unix()},
			230: {ID: 230, Title: "later follow-up", State: "open", Created: t1.Add(-time.Hour * 2).Unix()},
			5:   {ID: 5, Title: "made long after", State: "open", Created: t1.Add(24 * time.Hour).Unix()},
		},
		byBranch: map[string][]Discussion{"design-deploy-credential": {{ID: 231, Title: "review", State: "closed"}}},
	}
	return g, rel, disc
}

func TestBuild(t *testing.T) {
	g, rel, disc := fixture()
	links := Links{"v0.10.0": {"CI can deploy.": {"design-deploy-credential"}}}
	c, err := Build(Sources{g, rel, disc}, testPeople, links, testSite(t))
	if err != nil {
		t.Fatal(err)
	}
	if len(c.Releases) != 2 || c.Releases[0].Tag != "v0.10.0" || c.Releases[1].Tag != "v0.9.0" {
		t.Fatalf("releases out of order: %+v", c.Releases)
	}
	r := c.Releases[0]
	if !r.Published || r.NotesURL != NotesBase+"v0.10.0" || r.Notes.Form != "bullets" {
		t.Fatalf("notes = %+v", r)
	}
	bl := r.Notes.Sections[0].Bullets[0]
	if !reflect.DeepEqual(bl.Branches, []string{"design-deploy-credential"}) || !reflect.DeepEqual(bl.Docs, []string{"/docs/cli#carlos-services"}) {
		t.Fatalf("bullet = %+v", bl)
	}
	if len(r.Changes) != 3 {
		t.Fatalf("changes = %+v", r.Changes)
	}
	direct, merge, squash := r.Changes[0], r.Changes[1], r.Changes[2]

	if squash.Branch != "design-deploy-credential" || squash.BranchURL != RepoURL+"/-/branch/design-deploy-credential" || squash.Commits != 2 {
		t.Errorf("squash = %+v", squash)
	}
	if want := []Credit{{Person: "Paul Campbell", Agents: []string{"claude", "codex"}}}; !reflect.DeepEqual(squash.Credit, want) {
		t.Errorf("squash credit = %+v", squash.Credit)
	}
	var ids []int
	for _, d := range squash.Discussions {
		ids = append(ids, d.ID)
	}
	if !reflect.DeepEqual(ids, []int{229, 230, 231}) {
		t.Errorf("squash discussions = %v", ids)
	}
	if !reflect.DeepEqual(squash.Docs, []string{"/docs/cli#carlos-services"}) {
		t.Errorf("squash docs = %v", squash.Docs)
	}

	if merge.Branch != "availability-tab" || merge.BranchURL != "" || merge.Commits != 1 {
		t.Errorf("merge = %+v", merge)
	}
	if want := []Credit{{Person: "Bill Horsman"}}; !reflect.DeepEqual(merge.Credit, want) {
		t.Errorf("merge credit = %+v", merge.Credit)
	}
	if len(merge.Discussions) != 0 {
		t.Errorf("a #N created after the commit was kept: %+v", merge.Discussions)
	}

	if direct.Branch != "" || direct.BranchURL != "" {
		t.Errorf("direct = %+v", direct)
	}
	if want := []Credit{{Person: "Paul Campbell", Agents: []string{"claude"}}}; !reflect.DeepEqual(direct.Credit, want) {
		t.Errorf("direct credit = %+v", direct.Credit)
	}
	// carlos gone is not a heading today; the index page has no
	// heading above line 3 beyond its h1, so it links the page.
	if !reflect.DeepEqual(direct.Docs, []string{"/docs/"}) {
		t.Errorf("direct docs = %v", direct.Docs)
	}

	if old := c.Releases[1]; old.Notes.Form != "markdown" || len(old.Changes) != 1 || old.Changes[0].Discussions != nil {
		t.Errorf("v0.9.0 = %+v", old)
	}
}

func TestBuildTombstoneNewerThanSquashIsIgnored(t *testing.T) {
	g, rel, disc := fixture()
	g.tombstones["design-deploy-credential"] = Tag{SHA: "tomb", Date: t1.Add(72 * time.Hour)}
	c, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t))
	if err != nil {
		t.Fatal(err)
	}
	sq := c.Releases[0].Changes[2]
	if sq.Commits != 1 || sq.BranchURL == "" {
		t.Fatalf("squash = %+v", sq)
	}
}

func TestBuildUnpublishedAndEmptyRelease(t *testing.T) {
	g, rel, disc := fixture()
	g.tags = append(g.tags, Tag{Name: "v0.10.1", SHA: "d1", Date: t1})
	c, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t))
	if err != nil {
		t.Fatal(err)
	}
	r := c.Releases[0]
	if r.Tag != "v0.10.1" || r.Published || r.Notes != nil || r.NotesURL != "" || r.Changes == nil || len(r.Changes) != 0 {
		t.Fatalf("v0.10.1 = %+v", r)
	}
}

func TestBuildLinksErrors(t *testing.T) {
	g, rel, disc := fixture()
	for name, links := range map[string]Links{
		"unknown lead":   {"v0.10.0": {"Not a bullet.": {"design-deploy-credential"}}},
		"foreign branch": {"v0.10.0": {"Other.": {"some-other-branch"}}},
	} {
		if _, err := Build(Sources{g, rel, disc}, testPeople, links, testSite(t)); err == nil || !strings.Contains(err.Error(), "changelog-links.json") {
			t.Errorf("%s: err = %v", name, err)
		}
	}
}

func TestBuildUnknownPersonFails(t *testing.T) {
	g, rel, disc := fixture()
	g.firstParent["..v0.9.0"] = []Commit{{SHA: "o1", AuthorName: "Stranger", AuthorEmail: "who@example.com", Date: t0, Message: "x"}}
	_, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t))
	if err == nil || !strings.Contains(err.Error(), "who@example.com") {
		t.Fatalf("err = %v", err)
	}
}

func TestCheckPublic(t *testing.T) {
	for _, s := range []string{"live for bill@ on Tito's console", "see github.com/carlosframework/releases and /skills", "a @mention"} {
		ok := &Changelog{Releases: []Release{{Tag: "v1.0.0", Changes: []Change{{Subject: s}}}}}
		if err := CheckPublic(ok, testPeople); err != nil {
			t.Errorf("%q refused: %v", s, err)
		}
	}
	for _, s := range []string{
		"thanks paul@tito.io",
		"by claude~someone@keymail.dev",
		"write to ops@example.org",
		"see https://github.com/carlosframework/platform/pull/409",
		"in github.com/carlosframework/carloku-infrastructure",
		"[contact](mailto:ops&#64;example.org)",
		"[source](https://github.com/carlosframework/plat&#102;orm)",
		"[source](https://github.com/carlosframework/plat%66orm)",
		"write to ops\\@example.org",
		"ops&amp;#64;example.org",
		"see **ops@example**.org now",
		"[source](https://github.com/carlosframework/./platform)",
		"[source](https://github.com/carlosframework/public/../platform.git)",
	} {
		bad := &Changelog{Releases: []Release{{Tag: "v1.0.0", Changes: []Change{{Subject: s}}}}}
		if err := CheckPublic(bad, testPeople); err == nil {
			t.Errorf("%q passed", s)
		}
		inNotes := &Changelog{Releases: []Release{{Tag: "v1.0.0", Notes: &Notes{Form: "markdown", MD: s}}}}
		if err := CheckPublic(inNotes, testPeople); err == nil {
			t.Errorf("%q in notes passed", s)
		}
	}
}

// A branch stacked on one that was squashed first must not count the
// first branch's commits again (4d13aec3 on 99084d7a in this repo).
func TestBuildStackedBranchSubtractsLandedCommits(t *testing.T) {
	g, rel, disc := fixture()
	lib := Commit{SHA: "c1", AuthorName: "claude", AuthorEmail: "claude~paul@keymail.dev", Date: t1, Message: "start"}
	sel := Commit{SHA: "c3", AuthorName: "codex", AuthorEmail: "codex~paul@keymail.dev", Date: t1, Message: "selector"}
	squash2 := Commit{SHA: "s2", Parents: []string{"d1"}, AuthorName: "codex", AuthorEmail: "codex~paul@keymail.dev", Date: t1,
		Message: "genselect\n\nSquashed from feat/genselect into main."}
	g.tags = append(g.tags, Tag{Name: "v0.11.0", SHA: "s2", Date: t1})
	g.firstParent["v0.9.0,v0.10.0..v0.11.0"] = []Commit{squash2}
	g.ranges["d1..tomb2"] = []Commit{sel, lib}
	g.tombstones["feat/genselect"] = Tag{SHA: "tomb2", Date: t1}
	c, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t))
	if err != nil {
		t.Fatal(err)
	}
	ch := c.Releases[0].Changes[0]
	if ch.Commits != 1 || !reflect.DeepEqual(ch.Credit, []Credit{{Person: "Paul Campbell", Agents: []string{"codex"}}}) {
		t.Fatalf("stacked change = %+v", ch)
	}
}

// The website anchors only levels two to four, so an addition under a
// page's h1 links the page (v0.15.0's CLI intro, 4235e9fd).
func TestDocsLinksSkipUnanchoredLevels(t *testing.T) {
	g, rel, disc := fixture()
	g.docs["d1"] = []DocsChange{{Page: "cli", Body: cliPage, Added: []int{2}}}
	c, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t))
	if err != nil {
		t.Fatal(err)
	}
	if got := c.Releases[0].Changes[0].Docs; !reflect.DeepEqual(got, []string{"/docs/cli"}) {
		t.Fatalf("docs = %v", got)
	}
}

func TestDiscussionLookupsAreCached(t *testing.T) {
	g, rel, disc := fixture()
	g.firstParent["..v0.9.0"] = []Commit{
		{SHA: "o1", AuthorName: "Paul Campbell", AuthorEmail: "paul@tito.io", Date: t1, Message: "a #229"},
		{SHA: "o2", AuthorName: "Paul Campbell", AuthorEmail: "paul@tito.io", Date: t1, Message: "b #229"},
	}
	if _, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t)); err != nil {
		t.Fatal(err)
	}
	// 229 once across three messages, 230 from the squash's own commit,
	// 417 and 5 from the merge.
	if disc.shows != 4 {
		t.Fatalf("Show called %d times, want 4", disc.shows)
	}
}

func TestSemverLess(t *testing.T) {
	if !semverLess("v0.9.0", "v0.10.0") || semverLess("v0.22.2", "v0.22.1") || !semverLess("v0.24.1", "v1.0.0") {
		t.Fatal("semver order wrong")
	}
}

func TestRedactQuotedRecords(t *testing.T) {
	g, rel, disc := fixture()
	disc.byBranch["design-deploy-credential"] = []Discussion{{ID: 231, Title: "send as jelly@tito.io (two accounts)", State: "closed"}}
	g.firstParent["v0.9.0..v0.10.0"][0].Message = "docs: thanks to ops@example.org and claude~paul@keymail.dev"
	c, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t))
	if err != nil {
		t.Fatal(err)
	}
	if got := c.Releases[0].Changes[0].Subject; got != "docs: thanks to [address] and [address]" {
		t.Errorf("subject = %q", got)
	}
	ds := c.Releases[0].Changes[2].Discussions
	if ds[len(ds)-1].Title != "send as [address] (two accounts)" {
		t.Errorf("discussions = %+v", ds)
	}
}

// v0.22.1 was tagged and never published; v0.22.2 shipped its change.
// v0.3.0 was cut from a commit v0.2.0 (unpublished) already held.
func TestRangeBases(t *testing.T) {
	earlier := []Release{{Tag: "v0.1.0", Published: true}, {Tag: "v0.2.0"}, {Tag: "v0.3.0", Published: true}}
	if got := RangeBases(true, earlier); !reflect.DeepEqual(got, []string{"v0.1.0", "v0.3.0"}) {
		t.Errorf("published bases = %v", got)
	}
	if got := RangeBases(false, earlier); !reflect.DeepEqual(got, []string{"v0.1.0", "v0.2.0", "v0.3.0"}) {
		t.Errorf("unpublished bases = %v", got)
	}
}

func TestBuildReusesAChangeListedTwice(t *testing.T) {
	g, rel, disc := fixture()
	g.tags = append(g.tags, Tag{Name: "v0.11.0", SHA: "d1", Date: t1})
	rel["v0.11.0"] = "carlos v0.11.0 (platform d1, 2026-10-05)\n\n- **Again.** x\n"
	delete(rel, "v0.10.0")
	g.firstParent["v0.9.0..v0.11.0"] = g.firstParent["v0.9.0..v0.10.0"]
	c, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t))
	if err != nil {
		t.Fatal(err)
	}
	a, b := c.Releases[0].Changes, c.Releases[1].Changes
	if len(a) != 3 || !reflect.DeepEqual(a, b) {
		t.Fatalf("v0.11.0 = %+v\nv0.10.0 = %+v", a, b)
	}
}

func TestDescribe(t *testing.T) {
	own := []Commit{{Message: "later work"}, {Message: "console: the first step\n\nbody"}}
	cases := []struct{ msg, branch, want string }{
		{"park: the engine (Plan 4)\n\nbody", "feat/park", "park: the engine (Plan 4)"},
		{"Merge branch 'tenant-iso-mail' into main\n\nMail: members can't adopt (#216)\n", "tenant-iso-mail", "Mail: members can't adopt (#216)"},
		{"Merge pull request #3 from carlosframework/depth\n\nTenant hibernation", "depth", "Tenant hibernation"},
		{"fix/x\n\nSquashed from fix/x into main.\n\nCo-Authored-By: Claude <noreply@anthropic.com>", "fix/x", "console: the first step"},
		{"fix/x\n\nSquashed from fix/x into main.", "fix/x", "fix/x"},
	}
	for i, c := range cases {
		o := own
		if i == len(cases)-1 {
			o = nil
		}
		if got := Describe(c.msg, c.branch, o); got != c.want {
			t.Errorf("Describe(%q) = %q, want %q", c.msg, got, c.want)
		}
	}
}

func TestBuildPublishedWithEmptyNotes(t *testing.T) {
	g, rel, disc := fixture()
	rel["v0.10.0"] = "\n"
	c, err := Build(Sources{g, rel, disc}, testPeople, nil, testSite(t))
	if err != nil {
		t.Fatal(err)
	}
	if r := c.Releases[0]; !r.Published || r.NotesURL == "" || r.Notes != nil {
		t.Fatalf("v0.10.0 = %+v", r)
	}
}