package tui

import (
	"fmt"
	"strings"

	"github.com/lerko/nib/internal/db"
)

type filterModel struct {
	tags   []db.TagCount
	cursor int
	height int
}

func newFilterModel() filterModel {
	return filterModel{}
}

func (f *filterModel) setTags(tags []db.TagCount) {
	f.tags = tags
	f.cursor = 0
}

func (f *filterModel) setHeight(h int) {
	f.height = h
}

func (f filterModel) selectedTag() string {
	if len(f.tags) == 0 || f.cursor >= len(f.tags) {
		return ""
	}
	return f.tags[f.cursor].Tag
}

func (f filterModel) update(key string) filterModel {
	switch key {
	case "up", "k":
		if f.cursor > 0 {
			f.cursor--
		}
	case "down", "j":
		if f.cursor < len(f.tags)-1 {
			f.cursor++
		}
	}
	return f
}

func (f filterModel) view(width int) string {
	if len(f.tags) == 0 {
		return statusStyle.Render("no tags")
	}

	var b strings.Builder
	b.WriteString(titleStyle.Render("filter by tag"))
	b.WriteString("\n\n")

	visible := f.height - 4
	if visible <= 0 {
		visible = 10
	}

	offset := 0
	if f.cursor >= visible {
		offset = f.cursor - visible + 1
	}
	end := min(offset+visible, len(f.tags))

	for i := offset; i < end; i++ {
		tc := f.tags[i]
		tag := fmt.Sprintf("#%-20s %d", tc.Tag, tc.Count)
		if i == f.cursor {
			b.WriteString(selectedItemStyle.Render(" " + tagStyle.Render(tag)))
		} else {
			b.WriteString(listItemStyle.Render(tagStyle.Render(tag)))
		}
		if i < end-1 {
			b.WriteString("\n")
		}
	}

	return b.String()
}