package tui

import (
	"fmt"
	"strings"

	"github.com/charmbracelet/bubbles/textinput"
	tea "github.com/charmbracelet/bubbletea"

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

type fillSlot struct {
	Name    string
	Default string
	Value   string
}

type fillModel struct {
	slots    []fillSlot
	active   int
	body     string
	entityID string
	ti       textinput.Model
}

func newFillModel(entityID, body string) fillModel {
	slots := discoverSlots(body)
	m := fillModel{
		slots:    slots,
		body:     body,
		entityID: entityID,
	}
	m.ti = textinput.New()
	m.ti.CharLimit = 200
	if len(slots) > 0 {
		m.ti.Placeholder = slots[0].Name
		m.ti.Focus()
		if slots[0].Default != "" {
			m.ti.SetValue(slots[0].Default)
		}
	}
	return m
}

func discoverSlots(body string) []fillSlot {
	matches := carddata.TemplateSlotRe.FindAllStringSubmatch(body, -1)
	seen := map[string]bool{}
	var slots []fillSlot
	for _, m := range matches {
		name := m[1]
		if !seen[name] {
			seen[name] = true
			slots = append(slots, fillSlot{Name: name})
		}
	}
	return slots
}

func (f fillModel) resolve() string {
	result := f.body
	for _, s := range f.slots {
		val := s.Value
		if val == "" {
			val = "${" + s.Name + "}"
		}
		result = strings.ReplaceAll(result, "${"+s.Name+"}", val)
	}
	return result
}

func (f fillModel) update(msg tea.KeyMsg) (fillModel, tea.Cmd) {
	switch msg.String() {
	case "tab":
		f.commitActive()
		if f.active < len(f.slots)-1 {
			f.active++
		} else {
			f.active = 0
		}
		f.loadActive()
		return f, nil
	case "shift+tab":
		f.commitActive()
		if f.active > 0 {
			f.active--
		} else {
			f.active = len(f.slots) - 1
		}
		f.loadActive()
		return f, nil
	}

	f.ti, _ = f.ti.Update(msg)
	return f, nil
}

func (f *fillModel) commitActive() {
	if f.active < len(f.slots) {
		f.slots[f.active].Value = f.ti.Value()
	}
}

func (f *fillModel) loadActive() {
	if f.active < len(f.slots) {
		s := f.slots[f.active]
		f.ti.SetValue(s.Value)
		f.ti.Placeholder = s.Name
		f.ti.Focus()
	}
}

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

	var b strings.Builder
	header := fmt.Sprintf("⤓ filling   slot %d/%d", f.active+1, len(f.slots))
	b.WriteString(detailHeaderStyle.Render(header))
	b.WriteString("\n\n")

	for i, slot := range f.slots {
		name := detailLabelStyle.Render(slot.Name)
		var val string
		if i == f.active {
			val = f.ti.View()
		} else if slot.Value != "" {
			val = detailValueStyle.Render(slot.Value)
		} else {
			val = idStyle.Render("(empty)")
		}

		if i == f.active {
			b.WriteString(selectedItemStyle.Render(" " + name + "  " + val))
		} else {
			b.WriteString(listItemStyle.Render(name + "  " + val))
		}
		b.WriteString("\n")
	}

	b.WriteString("\n")
	preview := f.resolve()
	if len(preview) > width-4 {
		preview = preview[:width-7] + "…"
	}
	b.WriteString(detailBodyStyle.Render(preview))
	b.WriteString("\n\n")
	b.WriteString(helpStyle.Render("tab:next  shift+tab:prev  enter:copy  esc:cancel"))

	return b.String()
}