// The package defines an extensible TUI via the bubbletea framework.
//
// While the package remains in v0.0.X releases, this TUI may be undocumented.
package issues

import (
	"fmt"
	"strings"

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

// The main bubbletea Model
type Model struct {
	issue      Issue
	collection IssueCollection
	content    string
	Path       string
	selection  int // index for the collection browser
	// viewport viewport.Model
}

func (m Model) Init() tea.Cmd { return m.load }

// Handles quit logic and viewport scroll and size updates
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch msg.String() {
		case "q":
			return m, tea.Quit
		case "k":
			if m.selection+1 < len(m.collection) {
				m.selection = m.selection + 1
			} else {
				m.selection = 0
			}
			return m, m.renderIssueCollection
		case "j":
			if m.selection != 0 {
				m.selection = m.selection - 1
			} else {
				m.selection = len(m.collection) - 1
			}
			return m, m.renderIssueCollection
		case "enter":
			m.Path = m.collection[m.selection].Path
			return m, m.load
		}
	case Issue:
		m.issue = msg
		return m, m.renderIssue
	case IssueCollection:
		m.collection = msg
		return m, m.renderIssueCollection
	case string:
		m.content = msg
		return m, nil
	}

	return m, nil
}

// Handles load logic
func (m Model) load() tea.Msg {
	if IsIssue(m.Path) {
		issue, err := m.issue.NewFromPath(m.Path)

		if err != nil {
			return nil
		}

		return issue
	}

	if IsIssueCollection(m.Path) {
		collection, err := m.collection.NewFromPath(m.Path)

		if err != nil {
			return nil
		}

		return collection
	}

	return nil
}

// [lipgloss] style definitions
var (
	titleStyle = lipgloss.NewStyle().
			Bold(true).
			Underline(true)

	statusStyle = lipgloss.NewStyle().
			Faint(true).
			Italic(true)

	variadicTitleStyle = lipgloss.NewStyle().
				Align(lipgloss.Left).
				Italic(true)

	variadicDataStyle = lipgloss.NewStyle().
				Width(40).
				BorderStyle(lipgloss.ASCIIBorder())

	borderStyle = lipgloss.NewStyle().
			Padding(1, 2).
			Margin(1).
			BorderStyle(lipgloss.NormalBorder())

	indexStyle = lipgloss.NewStyle().
			Italic(true)

	pointerStyle = lipgloss.NewStyle().
			Faint(true)

	collectionStyleLeft = lipgloss.NewStyle().
				Align(lipgloss.Left)
)

// Handles all view logic for [issue.Issue]
func (m Model) renderIssue() tea.Msg {
	var output string
	// title
	output = output + titleStyle.Render(m.issue.Title)

	// status
	output = output + fmt.Sprintf("\n%s", statusStyle.Render(m.issue.Status.Data))

	// variadics
	var tags string
	for _, field := range m.issue.Tags.Fields {
		tags = tags + field.Path + ", "
	}
	tags = strings.TrimRight(tags, ", ")

	var blockedby string
	for _, field := range m.issue.Blockedby.Fields {
		blockedby = blockedby + field.Path + ", "
	}
	blockedby = strings.TrimRight(blockedby, ", ")

	if len(m.issue.Tags.Fields) > 0 {
		output = output + variadicTitleStyle.Render("\n\nTags:")
		output = output + fmt.Sprintf("\n%s", variadicDataStyle.Render(tags))
	}

	if len(m.issue.Blockedby.Fields) > 0 {
		output = output + variadicTitleStyle.Render("\n\nBlockedby:")
		output = output + fmt.Sprintf("\n%s", variadicDataStyle.Render(blockedby))
	}

	// description
	output = output + titleStyle.Render("\n\nDescription:\n")
	output = output + fmt.Sprintf("\n%s", m.issue.Description.Data)

	return borderStyle.Render(output)
}

func (m Model) renderIssueCollection() tea.Msg {
	var output string
	var left string
	output = output + "Issues in " + m.Path + "...\n\n"
	for i, issue := range m.collection {
		// pointer render
		if i == m.selection {
			left = left + pointerStyle.Render("-> ")
		} else {
			left = left + pointerStyle.Render("   ")
		}
		// index render
		left = left + "[" + indexStyle.Render(fmt.Sprintf("%d", i+1)) + "]: "

		// title render
		left = left + fmt.Sprintf("%s\n", titleStyle.Render(issue.Title))
	}

	output = output + collectionStyleLeft.Render(left)
	output = output + "\nj/k: down/up\tenter: select\tq: quit"
	return output
}

// Wraps [issue.Model.renderIssue] in a viewport
func (m Model) View() string {
	if len(m.content) == 0 {
		return "loading..."
	}
	return m.content
}