package tui

import (
	"fmt"
	"math"
	"strings"
	"time"

	"github.com/charmbracelet/glamour"

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

const staleThresholdDays = 30

type stumbleModel struct {
	entries []*db.Entity
	cursor  int
	width   int
	height  int
	done    bool
}

func newStumbleModel() stumbleModel {
	return stumbleModel{}
}

func (s *stumbleModel) setEntries(entries []*db.Entity) {
	s.entries = entries
	s.cursor = 0
	s.done = len(entries) == 0
}

func (s *stumbleModel) setSize(width, height int) {
	s.width = width
	s.height = height
}

func (s stumbleModel) current() *db.Entity {
	if s.done || len(s.entries) == 0 || s.cursor >= len(s.entries) {
		return nil
	}
	return s.entries[s.cursor]
}

func (s *stumbleModel) advance() {
	s.cursor++
	if s.cursor >= len(s.entries) {
		s.done = true
	}
}

func (s *stumbleModel) removeCurrent() {
	if s.cursor < len(s.entries) {
		s.entries = append(s.entries[:s.cursor], s.entries[s.cursor+1:]...)
		if s.cursor >= len(s.entries) {
			s.done = true
		}
	}
}

func (s stumbleModel) total() int {
	return len(s.entries)
}

func (s stumbleModel) view() string {
	if s.done {
		return s.doneView()
	}

	e := s.current()
	if e == nil {
		return s.doneView()
	}

	w := s.width
	var b strings.Builder

	progress := fmt.Sprintf("stumble [%d/%d]", s.cursor+1, len(s.entries))
	b.WriteString(detailHeaderStyle.Render(progress))
	b.WriteString("\n")
	b.WriteString(separatorStyle.Render(strings.Repeat("─", w)))
	b.WriteString("\n\n")

	glyph := display.DisplayGlyph(e.Glyph, e.CardType)
	title := e.Body
	if e.Title != nil {
		title = *e.Title
	}
	if len(title) > w-6 {
		title = title[:w-9] + "…"
	}
	b.WriteString("  " + glyphStyle.Render(glyph) + " " + title)
	b.WriteString("\n")

	var meta []string
	meta = append(meta, string(e.Glyph))
	if e.CardType != nil {
		meta = append(meta, string(*e.CardType))
	}
	for _, t := range e.Tags {
		meta = append(meta, tagStyle.Render("#"+t))
	}
	meta = append(meta, "captured "+e.CreatedAt.Format("Jan 2"))
	b.WriteString("  " + idStyle.Render(strings.Join(meta, " · ")))
	b.WriteString("\n\n")

	bodyWidth := w - 6
	if bodyWidth < 20 {
		bodyWidth = 20
	}
	r, _ := glamour.NewTermRenderer(
		glamour.WithStylePath(glamourStyle()),
		glamour.WithWordWrap(bodyWidth),
	)
	rendered, err := r.Render(e.Body)
	if err != nil {
		rendered = e.Body
	}
	rendered = strings.TrimRight(rendered, "\n")
	b.WriteString("  " + rendered)
	b.WriteString("\n\n")

	age := daysAgo(e.ModifiedAt)
	ageText := fmt.Sprintf("last touched %d days ago", age)
	b.WriteString("  " + stumbleAgeStyle.Render(ageText))
	b.WriteString("\n")
	b.WriteString(separatorStyle.Render(strings.Repeat("─", w)))

	lines := strings.Split(b.String(), "\n")
	if len(lines) > s.height {
		lines = lines[:s.height]
	}
	return strings.Join(lines, "\n")
}

func (s stumbleModel) doneView() string {
	var b strings.Builder
	b.WriteString("\n\n")
	b.WriteString(detailHeaderStyle.Render("  all caught up"))
	b.WriteString("\n\n")
	reviewed := s.total()
	if reviewed > 0 {
		b.WriteString(idStyle.Render(fmt.Sprintf("  %d entries reviewed", reviewed)))
	} else {
		b.WriteString(idStyle.Render("  no stale entries found"))
	}
	return b.String()
}

func daysAgo(t time.Time) int {
	return int(math.Floor(time.Since(t).Hours() / 24))
}

func staleParams() db.ListParams {
	threshold := time.Now().UTC().AddDate(0, 0, -staleThresholdDays)
	return db.ListParams{
		ModifiedBefore: &threshold,
		Sort:           "modified_at",
		Order:          "asc",
		Limit:          50,
	}
}