package tui

import (
	tea "github.com/charmbracelet/bubbletea"

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

type viewState int

const (
	stateList viewState = iota
	stateDetail
	stateInput
	stateTagFilter
	stateConfirm
)

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

	list     listModel
	detail   detailModel
	input    inputModel
	filter   filterModel
	showHelp bool

	filterTag string
	confirmID string

	status string
	err    error
}

func newModel(store *db.Store) model {
	return model{
		store:  store,
		state:  stateList,
		list:   newListModel(),
		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
	}
	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.detail.setSize(m.width, m.contentHeight())
		m.filter.setHeight(m.contentHeight())
		return m, nil

	case entitiesLoadedMsg:
		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 = "promoted → snippet"
		return m, m.reloadDetail(msg.id)

	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)
		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 "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.list.selected(); e != nil {
				m.detail.setEntity(e)
				m.state = stateDetail
			}
		}
		return m, nil

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

	case "x":
		if m.state == stateList {
			if e := m.list.selected(); 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":
		if m.state == stateDetail && m.detail.entity != nil {
			if m.detail.entity.CardType != nil {
				m.status = "already a card"
				return m, nil
			}
			return m, promoteEntity(m.store, m.detail.entity.ID)
		}
		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:
		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) View() string {
	if m.showHelp {
		return renderHelp(m.width, m.height)
	}

	var content string
	switch m.state {
	case stateList, stateInput, stateConfirm:
		content = m.list.view(m.width)
	case stateDetail:
		content = m.detail.view(m.width)
	case stateTagFilter:
		content = m.filter.view(m.width)
	}

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

	footer := m.footerView()

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

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 m.state {
	case stateList:
		return m.list.selected()
	case stateDetail:
		return m.detail.entity
	}
	return nil
}

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)
}