package tui

import (
	"fmt"
	"strings"

	"github.com/charmbracelet/lipgloss"

	"git.unkin.net/unkin/forgebot/pkg/models"
)

var columnOrder = []columnDef{
	{status: models.StatusTodo, title: "Todo", extra: ""},
	{status: models.StatusInProgress, title: "In Progress", extra: ""},
	{status: models.StatusInReview, title: "In Review", extra: ""},
	{status: models.StatusDone, title: "Done", extra: string(models.StatusWontdo)},
}

type columnDef struct {
	status models.TaskStatus
	title  string
	extra  string
}

type column struct {
	def    columnDef
	tasks  []models.Task
	cursor int
	offset int
}

type board struct {
	columns   [4]column
	activeCol int
}

func newBoard() board {
	var b board
	for i, def := range columnOrder {
		b.columns[i] = column{def: def}
	}
	return b
}

func (b *board) loadTasks(tasks []models.Task) {
	for i := range b.columns {
		b.columns[i].tasks = nil
	}
	for _, t := range tasks {
		for i := range b.columns {
			col := &b.columns[i]
			if t.Status == col.def.status || string(t.Status) == col.def.extra {
				col.tasks = append(col.tasks, t)
				break
			}
		}
	}
	for i := range b.columns {
		col := &b.columns[i]
		if col.cursor >= len(col.tasks) {
			col.cursor = max(0, len(col.tasks)-1)
		}
	}
}

func (b *board) selectedTask() *models.Task {
	col := &b.columns[b.activeCol]
	if len(col.tasks) == 0 {
		return nil
	}
	return &col.tasks[col.cursor]
}

func (b *board) moveLeft() {
	if b.activeCol > 0 {
		b.activeCol--
	}
}

func (b *board) moveRight() {
	if b.activeCol < len(b.columns)-1 {
		b.activeCol++
	}
}

func (b *board) moveUp() {
	col := &b.columns[b.activeCol]
	if col.cursor > 0 {
		col.cursor--
	}
}

func (b *board) moveDown() {
	col := &b.columns[b.activeCol]
	if col.cursor < len(col.tasks)-1 {
		col.cursor++
	}
}

func (b *board) view(width, height int) string {
	colWidth := width / 4
	if colWidth < 20 {
		colWidth = 20
	}

	cardHeight := height - 4
	if cardHeight < 1 {
		cardHeight = 1
	}

	var cols []string
	for i := range b.columns {
		cols = append(cols, b.renderColumn(i, colWidth, cardHeight))
	}
	return lipgloss.JoinHorizontal(lipgloss.Top, cols...)
}

func (b *board) renderColumn(idx, width, maxHeight int) string {
	col := &b.columns[idx]
	color := statusColors[col.def.status]
	active := idx == b.activeCol

	titleStyle := columnTitleStyle.
		Width(width).
		Align(lipgloss.Center).
		Foreground(color)
	if active {
		titleStyle = titleStyle.Underline(true)
	}

	title := titleStyle.Render(fmt.Sprintf("%s (%d)", col.def.title, len(col.tasks)))

	if col.offset > col.cursor {
		col.offset = col.cursor
	}

	var cards []string
	usedHeight := 0
	visibleStart := col.offset
	for j := visibleStart; j < len(col.tasks); j++ {
		selected := active && j == col.cursor
		card := renderCard(col.tasks[j], width, selected)
		cardLines := strings.Count(card, "\n") + 1
		if usedHeight+cardLines > maxHeight && len(cards) > 0 {
			break
		}
		cards = append(cards, card)
		usedHeight += cardLines
	}

	if col.cursor >= visibleStart+len(cards) && len(col.tasks) > 0 {
		col.offset = col.cursor
		return b.renderColumn(idx, width, maxHeight)
	}

	content := strings.Join(cards, "\n")
	if len(col.tasks) == 0 {
		content = dimStyle.Width(width).Align(lipgloss.Center).Render("empty")
	}

	scrollInfo := ""
	if col.offset > 0 {
		scrollInfo = dimStyle.Render(fmt.Sprintf("↑ %d more", col.offset))
	}
	remaining := len(col.tasks) - visibleStart - len(cards)
	if remaining > 0 {
		if scrollInfo != "" {
			scrollInfo += "  "
		}
		scrollInfo += dimStyle.Render(fmt.Sprintf("↓ %d more", remaining))
	}

	parts := []string{title}
	if scrollInfo != "" {
		parts = append(parts, scrollInfo)
	}
	parts = append(parts, content)

	return lipgloss.JoinVertical(lipgloss.Left, parts...)
}