package tui

import (
	"fmt"

	tea "github.com/charmbracelet/bubbletea"

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

type viewState int

const (
	stateList viewState = iota
	stateDetail
	stateInput
	stateTagFilter
	stateConfirm
	statePromote
)

type viewMode int

const (
	modeStream viewMode = iota
	modeCards
)

type cardsSort int

const (
	sortNewest cardsSort = iota
	sortOldest
	sortMostUsed
)

func (s cardsSort) String() string {
	switch s {
	case sortOldest:
		return "oldest"
	case sortMostUsed:
		return "most used"
	default:
		return "newest"
	}
}

func (s cardsSort) next() cardsSort {
	switch s {
	case sortNewest:
		return sortOldest
	case sortOldest:
		return sortMostUsed
	default:
		return sortNewest
	}
}

type model struct {
	store  *db.Store
	state  viewState
	mode   viewMode
	width  int
	height int

	list     listModel
	cards    cardsModel
	detail   detailModel
	input    inputModel
	filter   filterModel
	promote  promoteModel
	showHelp bool

	filterTag string
	confirmID string
	cardsSort cardsSort

	status string
	err    error
}

func newModel(store *db.Store) model {
	return model{
		store:  store,
		state:  stateList,
		mode:   modeStream,
		list:   newListModel(),
		cards:  newCardsModel(),
		detail: newDetailModel(),
		input:  newInputModel(),
		filter: newFilterModel(),
	}
}

func (m model) Init() tea.Cmd {
	return loadEntities(m.store, m.listParams())
}

func (m model) listParams() db.ListParams {
	p := db.DefaultListParams()
	if m.filterTag != "" {
		p.Tag = &m.filterTag
	}
	if m.mode == modeCards {
		p.CardsOnly = true
		switch m.cardsSort {
		case sortNewest:
			p.Sort = "created"
			p.Order = "desc"
		case sortOldest:
			p.Sort = "created"
			p.Order = "asc"
		case sortMostUsed:
			p.Sort = "use_count"
			p.Order = "desc"
		}
	}
	return p
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.width = msg.Width
		m.height = msg.Height
		m.list.setSize(m.width, m.contentHeight())
		m.cards.setSize(m.width, m.contentHeight())
		m.detail.setSize(m.width, m.contentHeight())
		m.filter.setHeight(m.contentHeight())
		return m, nil

	case entitiesLoadedMsg:
		if m.mode == modeCards {
			m.cards.setEntities(msg.entities)
		} else {
			m.list.setEntities(msg.entities)
		}
		m.err = nil
		return m, nil

	case entityCreatedMsg:
		m.state = stateList
		m.input.reset()
		m.status = "created"
		return m, loadEntities(m.store, m.listParams())

	case entityDeletedMsg:
		m.status = "deleted"
		m.state = stateList
		return m, loadEntities(m.store, m.listParams())

	case entityUpdatedMsg:
		m.status = msg.action
		if m.state == stateDetail {
			m.detail.setEntity(msg.entity)
		}
		return m, loadEntities(m.store, m.listParams())

	case entityPromotedMsg:
		m.status = fmt.Sprintf("promoted → %s", msg.cardType)
		m.state = stateList
		return m, loadEntities(m.store, m.listParams())

	case entityDemotedMsg:
		m.status = "demoted → fluid"
		return m, m.reloadDetail(msg.id)

	case entityCopiedMsg:
		m.status = "copied"
		return m, nil

	case tagsLoadedMsg:
		m.filter.setTags(msg.tags)
		m.state = stateTagFilter
		return m, nil

	case editorFinishedMsg:
		if msg.err != nil {
			m.err = msg.err
		} else {
			m.status = "updated"
		}
		return m, m.reloadAfterEdit()

	case confirmTimeoutMsg:
		if m.state == stateConfirm {
			m.state = stateList
			m.confirmID = ""
		}
		return m, nil

	case errMsg:
		m.err = msg.err
		return m, nil

	case tea.KeyMsg:
		m.err = nil
		switch m.state {
		case stateInput:
			return m.updateInput(msg)
		case stateTagFilter:
			return m.updateTagFilter(msg)
		case stateConfirm:
			return m.updateConfirm(msg)
		case statePromote:
			return m.updatePromote(msg)
		default:
			return m.updateKeys(msg)
		}
	}

	return m, nil
}

func (m model) updateKeys(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	if m.showHelp {
		if msg.String() == "?" || msg.String() == "esc" || msg.String() == "q" {
			m.showHelp = false
		}
		return m, nil
	}

	switch msg.String() {
	case "ctrl+c":
		return m, tea.Quit

	case "q":
		if m.state == stateList {
			return m, tea.Quit
		}
		return m, nil

	case "?":
		m.showHelp = true
		return m, nil

	case "1":
		if m.mode != modeStream {
			m.mode = modeStream
			m.state = stateList
			m.status = ""
			return m, loadEntities(m.store, m.listParams())
		}
		return m, nil

	case "2":
		if m.mode != modeCards {
			m.mode = modeCards
			m.state = stateList
			m.status = ""
			return m, loadEntities(m.store, m.listParams())
		}
		return m, nil

	case "s":
		if m.mode == modeCards && m.state == stateList {
			m.cardsSort = m.cardsSort.next()
			m.status = "sort: " + m.cardsSort.String()
			return m, loadEntities(m.store, m.listParams())
		}
		return m, nil

	case "tab":
		if m.mode == modeCards && m.state == stateList {
			m.cards.setIntent(m.cards.intent.next())
			return m, nil
		}
		return m, nil

	case "a":
		if m.state == stateList {
			m.state = stateInput
			m.input.focus()
			return m, m.input.ti.Focus()
		}

	case "esc":
		if m.state == stateDetail {
			m.state = stateList
			return m, nil
		}
		if m.state == stateList && m.filterTag != "" {
			m.filterTag = ""
			m.status = ""
			return m, loadEntities(m.store, m.listParams())
		}
		return m, nil

	case "enter":
		if m.state == stateList {
			if e := m.selectedEntity(); e != nil {
				m.detail.setEntity(e)
				m.state = stateDetail
			}
		}
		return m, nil

	case "d":
		if m.state == stateList {
			if e := m.selectedEntity(); e != nil {
				m.confirmID = e.ID
				m.state = stateConfirm
				return m, confirmTimeout()
			}
		}
		return m, nil

	case "x":
		if m.state == stateList {
			if e := m.selectedEntity(); e != nil && e.Glyph == db.GlyphTodo {
				return m, toggleTodo(m.store, e)
			}
		}
		return m, nil

	case "!":
		e := m.selectedEntity()
		if e != nil {
			return m, pinEntity(m.store, e)
		}
		return m, nil

	case "#":
		if m.state == stateList {
			if m.filterTag != "" {
				m.filterTag = ""
				m.status = ""
				return m, loadEntities(m.store, m.listParams())
			}
			return m, loadTags(m.store)
		}
		return m, nil

	case "p":
		e := m.selectedEntity()
		if e != nil {
			if e.CardType != nil {
				m.status = "already a card"
				return m, nil
			}
			m.promote = newPromoteModel(e.ID, e.Body)
			m.state = statePromote
			return m, nil
		}
		return m, nil

	case "D":
		if m.state == stateDetail && m.detail.entity != nil {
			if m.detail.entity.CardType == nil {
				m.status = "already fluid"
				return m, nil
			}
			return m, demoteEntity(m.store, m.detail.entity.ID)
		}
		return m, nil

	case "c":
		if m.state == stateDetail && m.detail.entity != nil {
			return m, copyToClipboard(m.store, m.detail.entity)
		}
		return m, nil

	case "e":
		if m.state == stateDetail && m.detail.entity != nil {
			return m, editInEditor(m.store, m.detail.entity)
		}
		return m, nil
	}

	switch m.state {
	case stateList:
		if m.mode == modeCards {
			m.cards = m.cards.update(msg)
		} else {
			m.list = m.list.update(msg)
		}
	case stateDetail:
		m.detail = m.detail.update(msg)
	}
	return m, nil
}

func (m model) updateInput(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	switch msg.String() {
	case "esc":
		m.state = stateList
		m.input.reset()
		return m, nil
	case "enter":
		if e := m.input.submit(); e != nil {
			return m, createEntity(m.store, e)
		}
		return m, nil
	}

	m.input = m.input.updateKey(msg)
	return m, nil
}

func (m model) updateTagFilter(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	switch msg.String() {
	case "esc", "q":
		m.state = stateList
		return m, nil
	case "enter":
		tag := m.filter.selectedTag()
		if tag != "" {
			m.filterTag = tag
			m.state = stateList
			return m, loadEntities(m.store, m.listParams())
		}
		return m, nil
	default:
		m.filter = m.filter.update(msg.String())
		return m, nil
	}
}

func (m model) updateConfirm(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	id := m.confirmID
	m.confirmID = ""
	m.state = stateList

	if msg.String() == "y" && id != "" {
		return m, deleteEntity(m.store, id)
	}
	return m, nil
}

func (m model) updatePromote(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	switch msg.String() {
	case "esc", "q":
		m.state = stateList
		return m, nil
	case "enter":
		ct := m.promote.selectedType()
		return m, promoteEntity(m.store, m.promote.entityID, ct, m.promote.body)
	default:
		m.promote = m.promote.update(msg.String())
		return m, nil
	}
}

func (m model) View() string {
	if m.showHelp {
		return renderHelp(m.width, m.height)
	}

	var content string
	switch m.state {
	case stateList, stateInput, stateConfirm:
		if m.mode == modeCards {
			content = m.cards.view(m.width)
		} else {
			content = m.list.view(m.width)
		}
	case stateDetail:
		content = m.detail.view(m.width)
	case stateTagFilter:
		content = m.filter.view(m.width)
	case statePromote:
		content = m.promote.view(m.width)
	}

	header := m.headerView()
	footer := m.footerView()

	return header + "\n" + content + "\n" + footer
}

func (m model) headerView() string {
	header := titleStyle.Render("nib")

	modeName := "stream"
	if m.mode == modeCards {
		modeName = "cards"
	}
	header += " " + modeStyle.Render(modeName)

	if m.filterTag != "" {
		header += " " + filterPillStyle.Render("#"+m.filterTag)
	}

	if m.mode == modeCards && m.cards.intent != intentAll {
		header += " " + affordanceStyle.Render(m.cards.intent.String())
	}

	if m.mode == modeCards {
		header += " " + idStyle.Render("("+m.cardsSort.String()+")")
	}

	return header
}

func (m model) footerView() string {
	if m.state == stateInput {
		return m.input.view(m.width)
	}

	if m.state == stateConfirm {
		return renderConfirm(m.confirmID)
	}

	if m.err != nil {
		return errorStyle.Render("error: " + m.err.Error())
	}

	if m.status != "" {
		return statusStyle.Render(m.status) + "  " + helpStyle.Render(contextHints(m))
	}

	return renderStatusBar(m, m.width)
}

func (m model) contentHeight() int {
	return m.height - 3
}

func (m model) selectedEntity() *db.Entity {
	switch {
	case m.state == stateDetail:
		return m.detail.entity
	case m.mode == modeCards:
		return m.cards.selected()
	default:
		return m.list.selected()
	}
}

func (m model) reloadDetail(id string) tea.Cmd {
	return tea.Batch(
		loadEntities(m.store, m.listParams()),
		func() tea.Msg {
			e, err := m.store.Get(id)
			if err != nil {
				return errMsg{err}
			}
			return entityUpdatedMsg{e, ""}
		},
	)
}

func (m model) reloadAfterEdit() tea.Cmd {
	if m.detail.entity == nil {
		return loadEntities(m.store, m.listParams())
	}
	return m.reloadDetail(m.detail.entity.ID)
}