package main

import (
	"database/sql"
	"errors"
	"fmt"
	"net/http"
	"regexp"
	"strings"

	"github.com/charmbracelet/bubbles/key"
	"github.com/charmbracelet/bubbles/textinput"
	"github.com/charmbracelet/bubbles/viewport"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/microcosm-cc/bluemonday"
	"github.com/muesli/reflow/wordwrap"
)

type model struct {
	wordInput         textinput.Model
	err               error
	currentWord       string
	currentDefinition string
	db                *sql.DB
	c                 *http.Client
	wordAddStatus     string
	p                 bluemonday.Policy
	vp                viewport.Model
	ankiDeck          string
	ankiModel         string
	apiURL            string
}

type (
	errMsg        error
	definitionMsg string
	wordAddedMsg  string
)

func initialModel(c *http.Client, db *sql.DB, apiURL, ankiDeck, ankiModel, firstWord string) model {
	ti := textinput.New()
	ti.Placeholder = ""
	ti.Focus()
	ti.CharLimit = 156
	ti.Width = 36

	vp := viewport.New(80, 30)
	vp.KeyMap = viewport.KeyMap{
		PageDown: key.NewBinding(
			key.WithKeys("pgdown", " ", "f"),
			key.WithHelp("f/pgdn", "page down"),
		),
		PageUp: key.NewBinding(
			key.WithKeys("pgup", "b"),
			key.WithHelp("b/pgup", "page up"),
		),
	}

	if firstWord != "" {
		ti.SetValue(firstWord)
	}

	return model{
		wordInput:     ti,
		err:           nil,
		db:            db,
		c:             c,
		wordAddStatus: "",
		p:             *bluemonday.StrictPolicy(),
		vp:            vp,
		ankiDeck:      ankiDeck,
		ankiModel:     ankiModel,
		apiURL:        apiURL,
		currentWord:   firstWord,
	}
}

func (m model) Init() tea.Cmd {
	cmds := []tea.Cmd{textinput.Blink}
	if m.currentWord != "" {
		cmds = append(cmds, lookupWord(m.db, m.currentWord))
	}
	return tea.Batch(cmds...)
}

func lookupWord(db *sql.DB, word string) tea.Cmd {
	return func() tea.Msg {
		word = strings.TrimSpace(word) // remove leading / trailing whitespace
		row := db.QueryRow(`select definition from words where word = ? limit 1`, word)
		var definition string
		err := row.Scan(&definition)
		if err != nil {
			if errors.Is(err, sql.ErrNoRows) {
				return definitionMsg("")
			}
			return errMsg(fmt.Errorf("looking up '%s': %s", word, err))
		}
		return definitionMsg(definition)
	}
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmd tea.Cmd

	var textPickerLongerCmds []tea.Cmd

	switch msg := msg.(type) {
	case definitionMsg:
		m.currentDefinition = string(msg)
		m.err = nil
		m.vp.SetContent(formatDefinitionForDisplay(m.p, m.currentDefinition, m.vp.Width))
		return m, nil
	case wordAddedMsg:
		m.wordAddStatus = fmt.Sprintf("✅ Added '%s' to Anki", string(msg))
		m.currentWord = ""
		m.currentDefinition = ""
		m.wordInput.SetValue("")
		m.vp.SetContent("")
		m.err = nil
	case tea.WindowSizeMsg:
		// headerHeight is the height of everything above the definition window.
		headerHeight := 11
		m.vp.Width = msg.Width
		m.vp.Height = msg.Height - headerHeight
		m.vp.SetContent(formatDefinitionForDisplay(m.p, m.currentDefinition, m.vp.Width))
	case tea.KeyMsg:
		switch msg.Type {
		case tea.KeyCtrlC:
			return m, tea.Quit
		case tea.KeyEsc:
			m.currentWord = ""
			m.currentDefinition = ""
			m.wordInput.SetValue("")
			m.vp.SetContent("")
		case tea.KeyEnter:
			return m, addCard(m.c, m.apiURL, m.ankiDeck, m.ankiModel, m.currentWord, m.currentDefinition)
		}

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

	if m.wordInput.Value() != m.currentWord {
		m.currentWord = m.wordInput.Value()
		textPickerLongerCmds = append(textPickerLongerCmds, lookupWord(m.db, m.currentWord))
	}

	var vpCmd tea.Cmd
	m.vp, vpCmd = m.vp.Update(msg)
	textPickerLongerCmds = append(textPickerLongerCmds, vpCmd)

	m.wordInput, cmd = m.wordInput.Update(msg)
	textPickerLongerCmds = append(textPickerLongerCmds, cmd)
	return m, tea.Batch(textPickerLongerCmds...)
}

var whitespaceTrimmerRe = regexp.MustCompile(`^[ \t]*$`)

func (m model) View() string {
	return fmt.Sprintf(
		"\x1b[1;30;42mLook up a word:\x1b[0m\n\n%s\n\n\x1b[1;30;42mStatus:\x1b[0m %s\n\n%s\n\n%s\n%s",
		m.wordInput.View(),
		formatStatus(m.err, m.wordAddStatus),
		"(Ctrl-C to quit, Esc to clear, Enter to add to Anki, PgUp/Down to scroll)",
		"\x1b[1;30;42mCurrent definition:\x1b[0m\n",
		m.vp.View(),
	) + "\n"
}

func formatDefinitionForDisplay(policy bluemonday.Policy, definition string, maxWidth int) string {
	// Add a hyphen to the start of each definition
	str := strings.ReplaceAll(definition, "<li class=sense>", "<li class=sense>- ")

	// Italicize examples
	str = strings.ReplaceAll(str, "\t<ul><li><i>", "\n\t<ul><li><i>\x1b[3;39;49m")
	str = strings.ReplaceAll(str, "</i></li></ul></li>", "</i></li></ul></li>\x1b[0m")

	// Remove all HTML tags
	str = policy.Sanitize(str)

	// Add some colour to the start of each definition
	str = strings.ReplaceAll(str, "\t- ", "\x1b[0;33;49m•\x1b[0m ")

	// Replace common HTML entities
	str = strings.ReplaceAll(str, "&#39;", "’")
	str = strings.ReplaceAll(str, "&amp;", "&")

	// Wrap
	width := min(maxWidth, 80)
	return wordwrap.String(str, width)
}

func formatStatus(lastError error, lastSuccess string) string {
	if lastError == nil {
		return lastSuccess
	}
	return fmt.Sprintf("\x1b[0;31;49m%s\x1b[0m", lastError.Error())
}