package inbox

import (
	"fmt"
	"io"
	"time"

	"github.com/charmbracelet/bubbles/list"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)

type EmailItem struct {
	UID       uint32
	From      string
	FromName  string
	Subject   string
	Date      time.Time
	Preview   string
	Account   string
	AccountID string
}

func (e EmailItem) FilterValue() string {
	return fmt.Sprintf("%s %s %s %s", e.Account, e.FromName, e.From, e.Subject)
}

func (e EmailItem) Title() string {
	return fmt.Sprintf("%s · %s - %s", e.Account, e.FromName, e.Subject)
}

func (e EmailItem) Description() string {
	return e.Preview
}

func formatTimeAgo(d time.Duration) string {
	if d < time.Minute {
		return "刚刚"
	}
	if d < time.Hour {
		mins := int(d.Minutes())
		return fmt.Sprintf("%d分钟前", mins)
	}
	if d < 24*time.Hour {
		hours := int(d.Hours())
		return fmt.Sprintf("%d小时前", hours)
	}
	if d < 7*24*time.Hour {
		days := int(d.Hours() / 24)
		return fmt.Sprintf("%d天前", days)
	}
	return d.Truncate(24 * time.Hour).String()
}

type InboxModel struct {
	list          list.Model
	emails        []EmailItem
	loading       bool
	err           error
	selectedEmail *EmailItem
}

func NewInboxModel() *InboxModel {
	l := list.New(nil, emailDelegate{}, 0, 10)
	l.Title = "收件箱"
	l.Styles.Title = inboxTitleStyle
	l.Styles.NoItems = inboxNoItemsStyle
	l.SetShowHelp(true)
	l.SetShowPagination(false)

	return &InboxModel{
		list:   l,
		emails: []EmailItem{},
	}
}

func (m *InboxModel) SetEmails(emails []EmailItem) {
	m.emails = emails
	items := make([]list.Item, len(emails))
	for i, e := range emails {
		items[i] = e
	}
	m.list.SetItems(items)
	m.list.Title = fmt.Sprintf("收件箱 (%d 封新邮件)", len(items))
}

func (m InboxModel) Init() tea.Cmd {
	return nil
}

func (m *InboxModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		if msg.String() == "ctrl+c" {
			return m, tea.Quit
		}
	case tea.WindowSizeMsg:
		m.list.SetWidth(msg.Width)
	}
	var cmd tea.Cmd
	m.list, cmd = m.list.Update(msg)
	return m, cmd
}

func (m InboxModel) View() string {
	if m.loading {
		return loadingStyle.Render("正在加载邮件...")
	}
	if m.err != nil {
		return errorStyle.Render(fmt.Sprintf("错误: %v", m.err))
	}
	return m.list.View()
}

func (m *InboxModel) SetLoading(loading bool) {
	m.loading = loading
}

func (m *InboxModel) SetError(err error) {
	m.err = err
}

func (m InboxModel) SelectedEmail() *EmailItem {
	idx := m.list.Index()
	if idx >= 0 && idx < len(m.emails) {
		return &m.emails[idx]
	}
	return nil
}

var (
	inboxTitleStyle = lipgloss.NewStyle().
			Foreground(lipgloss.Color("86")).
			Bold(true)

	inboxNoItemsStyle = lipgloss.NewStyle().
				Foreground(lipgloss.Color("241")).
				Padding(1, 2)

	loadingStyle = lipgloss.NewStyle().
			Foreground(lipgloss.Color("86")).
			Padding(1, 2)

	errorStyle = lipgloss.NewStyle().
			Foreground(lipgloss.Color("196")).
			Padding(1, 2)
)

type emailDelegate struct{}

func (d emailDelegate) Height() int  { return 1 }
func (d emailDelegate) Spacing() int { return 0 }
func (d emailDelegate) Update(msg tea.Msg, m *list.Model) tea.Cmd {
	return nil
}
func (d emailDelegate) Render(w io.Writer, m list.Model, index int, item list.Item) {
	email, ok := item.(EmailItem)
	if !ok {
		return
	}

	isSelected := index == m.Index()

	titleStyle := emailTitleStyle
	descStyle := emailDescStyle

	if isSelected {
		titleStyle = emailTitleStyleSelected
		descStyle = emailDescStyleSelected
	}

	fmt.Fprintf(w, "%s\n%s", titleStyle.Render(email.Title()), descStyle.Render(email.Description()))
}

var (
	emailTitleStyle = lipgloss.NewStyle().
			Foreground(lipgloss.Color("255"))

	emailTitleStyleSelected = lipgloss.NewStyle().
				Foreground(lipgloss.Color("255")).
				Background(lipgloss.Color("68"))

	emailDescStyle = lipgloss.NewStyle().
			Foreground(lipgloss.Color("241"))

	emailDescStyleSelected = lipgloss.NewStyle().
				Foreground(lipgloss.Color("186")).
				Background(lipgloss.Color("68"))
)