package server

import (
	"bytes"
	"html/template"
	"strings"

	"github.com/dal/kaos/internal/supervisor"
	"github.com/dal/kaos/web"
)

// taskCardData wraps a task with UI display info.
type taskCardData struct {
	supervisor.Task
	CanRun bool
	Action string // blocked, review, run, running, question, approve, done
}

// columnData holds data for rendering a single kanban column.
type columnData struct {
	Name  string
	Label string
	Icon  string
	Count int
	Tasks []taskCardData
}

// dashboardData holds data for the full dashboard page.
type dashboardData struct {
	Columns []columnData
}

// taskDetailData holds data for the task detail panel.
type taskDetailData struct {
	Task      supervisor.Task
	Content   string
	HasReport bool
}

// statusIcons maps folder names to emoji icons.
var statusIcons = map[string]string{
	"backlog": "📦",
	"ready":   "📋",
	"active":  "🔄",
	"review":  "👀",
	"done":    "✅",
}

// columnOrder defines the display order of columns.
var columnOrder = []string{"backlog", "ready", "active", "review", "done"}

// templateFuncs provides custom functions for templates.
var templateFuncs = template.FuncMap{
	"joinDeps": func(deps []string) string {
		return strings.Join(deps, ", ")
	},
}

// templates holds the parsed template set.
var templates *template.Template

func init() {
	templates = template.Must(
		template.New("").Funcs(templateFuncs).ParseFS(
			web.TemplatesFS,
			"templates/layout.html",
			"templates/dashboard.html",
			"templates/docs-list.html",
			"templates/docs-view.html",
			"templates/console.html",
			"templates/submit.html",
			"templates/partials/column.html",
			"templates/partials/task-card.html",
			"templates/partials/task-detail.html",
			"templates/partials/search-results.html",
		),
	)
}

// renderDashboard generates the full dashboard HTML page.
func renderDashboard(columns map[string][]supervisor.Task) string {
	// Build set of done task IDs for dependency checking
	doneSet := make(map[string]bool)
	for _, t := range columns["done"] {
		doneSet[t.ID] = true
	}

	data := buildDashboardData(columns, doneSet)

	var buf bytes.Buffer
	if err := templates.ExecuteTemplate(&buf, "layout.html", data); err != nil {
		return "Greška pri renderovanju: " + err.Error()
	}
	return buf.String()
}

// buildDashboardData creates dashboard data with task actions resolved.
func buildDashboardData(columns map[string][]supervisor.Task, doneSet map[string]bool) dashboardData {
	data := dashboardData{}
	for _, col := range columnOrder {
		tasks := columns[col]
		cards := make([]taskCardData, len(tasks))
		for i, t := range tasks {
			action := resolveTaskAction(t, doneSet)
			cards[i] = taskCardData{
				Task:   t,
				CanRun: action == "run",
				Action: action,
			}
		}
		data.Columns = append(data.Columns, columnData{
			Name:  col,
			Label: strings.ToUpper(col),
			Icon:  statusIcons[col],
			Count: len(tasks),
			Tasks: cards,
		})
	}
	return data
}

// renderBoardFragment generates only the board HTML for SSE updates.
func renderBoardFragment(columns map[string][]supervisor.Task) string {
	doneSet := make(map[string]bool)
	for _, t := range columns["done"] {
		doneSet[t.ID] = true
	}

	data := buildDashboardData(columns, doneSet)

	var buf bytes.Buffer
	if err := templates.ExecuteTemplate(&buf, "content", data); err != nil {
		return ""
	}
	return buf.String()
}

// resolveTaskAction determines which action button to show for a task.
func resolveTaskAction(t supervisor.Task, doneSet map[string]bool) string {
	switch t.Status {
	case "backlog":
		for _, dep := range t.DependsOn {
			if !doneSet[dep] {
				return "blocked"
			}
		}
		return "review" // deps met, needs operator review before ready
	case "ready":
		return "run"
	case "active":
		return "running"
	case "review":
		return "approve"
	case "done":
		return "done"
	default:
		return ""
	}
}

// renderDocsList generates the docs listing HTML page.
func renderDocsList(data docsListData) string {
	var buf bytes.Buffer
	if err := templates.ExecuteTemplate(&buf, "docs-list", data); err != nil {
		return "Greška pri renderovanju: " + err.Error()
	}
	return buf.String()
}

// renderDocsView generates the docs view HTML page.
func renderDocsView(data docsViewData) string {
	var buf bytes.Buffer
	if err := templates.ExecuteTemplate(&buf, "docs-view", data); err != nil {
		return "Greška pri renderovanju: " + err.Error()
	}
	return buf.String()
}

// renderConsolePage generates the console HTML page.
func renderConsolePage() string {
	var buf bytes.Buffer
	if err := templates.ExecuteTemplate(&buf, "console", nil); err != nil {
		return "Greška pri renderovanju: " + err.Error()
	}
	return buf.String()
}

// renderSubmitPage generates the submit page HTML.
func renderSubmitPage() string {
	var buf bytes.Buffer
	if err := templates.ExecuteTemplate(&buf, "submit", nil); err != nil {
		return "Greška pri renderovanju: " + err.Error()
	}
	return buf.String()
}

// renderSearchResults generates the search results HTML fragment.
func renderSearchResults(data searchResultsData) string {
	var buf bytes.Buffer
	if err := templates.ExecuteTemplate(&buf, "search-results", data); err != nil {
		return "Greška pri renderovanju: " + err.Error()
	}
	return buf.String()
}

// renderTaskDetail generates HTML fragment for task detail panel.
func renderTaskDetail(t supervisor.Task, content string, hasReport bool) string {
	data := taskDetailData{
		Task:      t,
		Content:   content,
		HasReport: hasReport,
	}

	var buf bytes.Buffer
	if err := templates.ExecuteTemplate(&buf, "task-detail", data); err != nil {
		return "Greška pri renderovanju: " + err.Error()
	}
	return buf.String()
}