package views

import (
	"strconv"
	"strings"

	"hearthforge/internal/config"
	"hearthforge/internal/db"
	"hearthforge/internal/util"

	g "maragu.dev/gomponents"
	. "maragu.dev/gomponents/html"
)

// LabelsQueryParam builds the "&labels=1,2" suffix the issue tabs reuse.
func LabelsQueryParam(ids []int64) string {
	if len(ids) == 0 {
		return ""
	}
	parts := make([]string, len(ids))
	for i, id := range ids {
		parts[i] = strconv.FormatInt(id, 10)
	}
	return "&labels=" + strings.Join(parts, ",")
}

// CanEdit reports whether user may edit or delete an issue, a patch or one
// of their comments. Admins always may. Authors may only while it is open.
func CanEdit(user *db.SessionUser, authorID *int64, status string) bool {
	if user == nil {
		return false
	}
	return user.IsAdmin || (authorID != nil && *authorID == user.ID && status == "open")
}

func labelBadge(label db.Label) g.Node {
	return Span(Class("label-badge"),
		Style("background:"+label.Color+";color:"+util.LabelTextColor(label.Color)),
		g.Text(label.Name))
}

// IssueList renders the issue index with status tabs, label filter and pages.
func IssueList(cfg *config.Config, user *db.SessionUser, repo *db.Repo, issues []db.Issue,
	status string, counts map[string]int, page PageInfo, repoLabels []db.Label,
	selectedLabelIDs []int64, labelsByIssueID map[int64][]db.Label,
) g.Node {
	labelsParam := LabelsQueryParam(selectedLabelIDs)
	tab := func(key, label string) g.Node {
		class := "list-tab"
		if status == key {
			class += " active"
		}
		return A(Href("/"+repo.Name+"/issues?status="+key+labelsParam), Class(class),
			g.Text(label+" "),
			g.If(counts[key] > 0, Span(Class("tab-count"), g.Text(strconv.Itoa(counts[key])))),
		)
	}
	selected := make(map[int64]bool, len(selectedLabelIDs))
	for _, id := range selectedLabelIDs {
		selected[id] = true
	}
	return Layout(Page{Title: "Issues — " + repo.Name, User: user, Cfg: cfg},
		Div(Class("container"),
			RepoHeader(repo),
			RepoNav(cfg, repo, "issues", user),
			Div(Class("list-header"),
				Div(Class("list-header-tabs"),
					tab("open", "Open"),
					tab("completed", "Completed"),
					tab("closed", "Closed"),
				),
				Div(Class("list-header-actions"),
					g.If(len(repoLabels) > 0, Details(Class("label-filter"),
						Summary(Class("btn btn-secondary btn-sm"),
							g.Text("Filter by label"),
							g.If(len(selectedLabelIDs) > 0,
								Span(Class("tab-count"), g.Text(strconv.Itoa(len(selectedLabelIDs))))),
						),
						Div(Class("label-filter-popup"),
							Form(Method("GET"), Action("/"+repo.Name+"/issues"),
								Input(Type("hidden"), Name("status"), Value(status)),
								Div(Class("label-filter-list"),
									g.Map(repoLabels, func(label db.Label) g.Node {
										return Label(Class("label-filter-item"),
											Input(Type("checkbox"), Name("labels"),
												Value(strconv.FormatInt(label.ID, 10)),
												g.If(selected[label.ID], Checked())),
											labelBadge(label),
										)
									}),
								),
								Div(Class("label-filter-actions"),
									Button(Type("submit"), Class("btn btn-primary btn-sm"), g.Text("Apply")),
									A(Href("/"+repo.Name+"/issues?status="+status),
										Class("btn btn-secondary btn-sm"), g.Text("Clear")),
								),
							),
						),
					)),
					g.If(user != nil, A(Href("/"+repo.Name+"/issues/new"),
						Class("btn btn-primary btn-sm"), g.Text("New issue"))),
				),
			),
			g.If(len(issues) == 0, Div(Class("empty-state"),
				P(g.Text("No "+status+" issues.")))),
			g.If(len(issues) > 0, Ul(Class("issue-list"),
				g.Map(issues, func(issue db.Issue) g.Node {
					labels := labelsByIssueID[issue.ID]
					return Li(Class("issue-item"),
						Div(Class("issue-main"),
							Span(Class("issue-status-dot "+issue.Status)),
							A(Href("/"+repo.Name+"/issues/"+strconv.FormatInt(issue.Number, 10)),
								Class("issue-title"), g.Text(issue.Title)),
							Span(Class("issue-number"), g.Text("#"+strconv.FormatInt(issue.Number, 10))),
						),
						g.If(len(labels) > 0, Div(Class("issue-labels"),
							g.Map(labels, labelBadge))),
						Div(Class("issue-meta"),
							Avatar(issue.AuthorID, issue.AuthorAvatarVersion, 20),
							Span(Class("issue-author"),
								g.Text("opened by "+util.DisplayName(deref(issue.AuthorUsername), cfg.OwnerDisplayName))),
							g.El("time", DateTime(issue.CreatedAt), g.Text(util.FormatDate(issue.CreatedAt))),
						),
					)
				}),
			)),
			Pagination(page),
		),
	)
}

// NewIssue renders the issue creation form.
func NewIssue(cfg *config.Config, user *db.SessionUser, repo *db.Repo, errMsg, template string,
	labels []db.Label,
) g.Node {
	showLabels := len(labels) > 0 && (user.IsAdmin || repo.AllowUserLabels)
	return Layout(Page{Title: "New issue — " + repo.Name, User: user, Cfg: cfg},
		Div(Class("container"),
			RepoHeader(repo),
			RepoNav(cfg, repo, "issues", user),
			H2(Class("section-title"), g.Text("New issue")),
			g.If(errMsg != "", P(Class("form-error"), g.Text(errMsg))),
			Form(Method("POST"), Action("/"+repo.Name+"/issues"), Class("form-card"),
				Div(Class("form-group"),
					Label(For("title"), g.Text("Title")),
					Input(ID("title"), Name("title"), Type("text"), Required(),
						MaxLength(strconv.Itoa(cfg.MaxTitleBytes)),
						Placeholder("Short, descriptive title")),
				),
				Div(Class("form-group"),
					Label(For("body"), g.Text("Description "),
						Span(Class("text-muted"), g.Text("(Markdown supported, optional)"))),
					Textarea(ID("body"), Name("body"), Rows("10"),
						MaxLength(strconv.Itoa(cfg.MaxTextBodyBytes)),
						Placeholder("Describe the issue..."), g.Text(template)),
				),
				g.If(showLabels, Div(Class("form-group"),
					Span(Class("form-group-label"), g.Text("Labels")),
					Div(Class("label-checkbox-list"),
						g.Map(labels, func(label db.Label) g.Node {
							return Label(Class("label-checkbox-item"),
								Input(Type("checkbox"), Name("label_ids"),
									Value(strconv.FormatInt(label.ID, 10))),
								labelBadge(label),
							)
						}),
					),
				)),
				Div(Class("form-actions"),
					Button(Type("submit"), Class("btn btn-primary"), g.Text("Submit issue")),
					A(Href("/"+repo.Name+"/issues"), Class("btn"), g.Text("Cancel")),
				),
			),
		),
	)
}

// IssueDetail renders one issue with its labels, body, reactions and comments.
func IssueDetail(cfg *config.Config, user *db.SessionUser, repo *db.Repo, issue *db.Issue,
	bodyHTML string, comments []ThreadComment, reactions []ReactionCount,
	commentReactions map[int64][]ReactionCount, issueLabels, repoLabels []db.Label,
) g.Node {
	baseURL := "/" + repo.Name + "/issues/" + strconv.FormatInt(issue.Number, 10)
	isAuthor := user != nil && issue.AuthorID != nil && user.ID == *issue.AuthorID
	canEditIssue := CanEdit(user, issue.AuthorID, issue.Status)
	canManageLabels := user != nil && (user.IsAdmin || (repo.AllowUserLabels && isAuthor))
	isAdmin := user != nil && user.IsAdmin
	closeLabel := "Reopen issue"
	if issue.Status == "open" {
		closeLabel = "Close issue"
	}
	return Layout(Page{Title: issue.Title + " — " + repo.Name, User: user, Cfg: cfg},
		Div(Class("container"),
			RepoHeader(repo),
			RepoNav(cfg, repo, "issues", user),
			Div(Class("issue-detail"),
				Div(Class("issue-detail-header"),
					Span(Class("issue-number"), g.Text("#"+strconv.FormatInt(issue.Number, 10))),
					EditableTitle(cfg, issue.Title, canEditIssue, baseURL+"/edit", "edit_body", issue.Body),
					Span(Class("issue-badge "+issue.Status), g.Text(issue.Status)),
					g.If(canEditIssue, Div(Class("issue-detail-meta-actions"),
						g.If(isAdmin && issue.Status == "open",
							Form(Method("POST"), Action(baseURL+"/complete"), Class("inline-form"),
								Button(Type("submit"), Class("btn btn-sm btn-primary"), g.Text("Completed")),
							)),
						g.If(isAdmin,
							Form(Method("POST"), Action(baseURL+"/close"), Class("inline-form"),
								Button(Type("submit"), Class("btn btn-sm"), g.Text(closeLabel)),
							)),
						Details(Class("confirm-details"),
							Summary(Class("btn btn-sm btn-danger"), g.Text("Delete")),
							Div(Class("confirm-popup"),
								g.Text("Permanently delete this issue?"),
								Form(Method("POST"), Action(baseURL+"/delete"), Class("inline-form"),
									Button(Type("submit"), Class("btn btn-sm btn-danger"), g.Text("Yes, delete")),
								),
							),
						),
					)),
				),

				LabelBadges(issueLabels, repoLabels, canManageLabels, baseURL),

				Div(Class("timeline-item"),
					Div(Class("timeline-author"),
						Avatar(issue.AuthorID, issue.AuthorAvatarVersion, 24),
						Strong(g.Text(util.DisplayName(deref(issue.AuthorUsername), cfg.OwnerDisplayName))),
						Div(Class("timeline-author-right"),
							g.If(canEditIssue, Details(Class("inline-edit-details"),
								Summary(Class("btn btn-xs"),
									Span(Class("when-closed"), g.Text("Edit")),
									Span(Class("when-open"), g.Text("Stop editing")),
								),
							)),
							DateWithEdited(issue.CreatedAt, issue.EditedAt),
						),
					),
					g.If(canEditIssue, Div(Class("inline-edit-form-area"),
						Form(Method("POST"), Action(baseURL+"/edit"), Class("inline-edit-form"),
							Input(Type("hidden"), Name("title"), Value(issue.Title)),
							Div(Class("form-group"),
								Textarea(Class("form-input"), ID("edit-issue-body"), Name("edit_body"),
									Rows("6"), MaxLength(strconv.Itoa(cfg.MaxTextBodyBytes)),
									g.Text(issue.Body)),
							),
							Div(Class("form-actions"),
								Button(Type("submit"), Class("btn btn-sm btn-primary"), g.Text("Save")),
							),
						),
					)),
					// The markdown renderer already sanitised this HTML.
					Div(Class("timeline-body markdown-body"),
						g.If(bodyHTML != "", g.Raw(bodyHTML)),
						g.If(bodyHTML == "", Em(Class("text-muted"), g.Text("No description provided."))),
					),
					ReactionBar(reactions, baseURL+"/react", 0, user),
				),

				CommentThread(cfg, user, comments, commentReactions, baseURL, issue.Status),
			),
		),
	)
}