package pages

import (
	"fmt"
	"log/slog"
	"strings"
	"tasksquire/common"
	"tasksquire/taskwarrior"
	"time"

	"github.com/charmbracelet/bubbles/key"
	"github.com/charmbracelet/bubbles/textinput"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/huh"
	"github.com/charmbracelet/lipgloss"
)

type Mode int

const (
	ModeNormal Mode = iota
	ModeInsert
	ModeAddTag
	ModeAddProject
)

type TaskEditorPage struct {
	common       *common.Common
	task         taskwarrior.Task
	form         *huh.Form
	mode         Mode
	statusline   tea.Model
	nFields      int
	currentField int

	// TODO: rework support for adding tags and projects
	additionalTags    string
	additionalProject string
}

type TaskEditorKeys struct {
	Quit        key.Binding
	Up          key.Binding
	Down        key.Binding
	Select      key.Binding
	ToggleFocus key.Binding
}

func NewTaskEditorPage(common *common.Common, task taskwarrior.Task) *TaskEditorPage {
	p := &TaskEditorPage{
		common: common,
		task:   task,
	}

	if p.task.Uuid == "" {
		p.mode = ModeInsert
	} else {
		p.mode = ModeNormal
	}

	if p.task.Priority == "" {
		p.task.Priority = "(none)"
	}
	if p.task.Project == "" {
		p.task.Project = "(none)"
	}

	priorityOptions := append([]string{"(none)"}, common.TW.GetPriorities()...)
	projectOptions := append([]string{"(none)"}, common.TW.GetProjects()...)
	tagOptions := common.TW.GetTags()

	p.form = huh.NewForm(
		huh.NewGroup(
			huh.NewInput().
				Title("Task").
				Value(&p.task.Description).
				Validate(func(desc string) error {
					if desc == "" {
						return fmt.Errorf("task description is required")
					}
					return nil
				}).
				Inline(true),

			huh.NewSelect[string]().
				Options(huh.NewOptions(priorityOptions...)...).
				Title("Priority").
				Value(&p.task.Priority),

			huh.NewSelect[string]().
				Options(huh.NewOptions(projectOptions...)...).
				Title("Project").
				Value(&p.task.Project),

			huh.NewInput().
				Title("Project").
				Value(&p.additionalProject).
				Validate(func(project string) error {
					if strings.Contains(project, " ") {
						return fmt.Errorf("project name cannot contain spaces")
					}
					return nil
				}).
				Inline(true),

			huh.NewMultiSelect[string]().
				Options(huh.NewOptions(tagOptions...)...).
				// Key("tags").
				Title("Tags").
				Value(&p.task.Tags),

			huh.NewInput().
				Title("Tags").
				Value(&p.additionalTags).
				Inline(true),

			huh.NewInput().
				Title("Due").
				Value(&p.task.Due).
				Validate(validateDate).
				Inline(true),

			huh.NewInput().
				Title("Scheduled").
				Value(&p.task.Scheduled).
				Validate(validateDate).
				Inline(true),

			huh.NewInput().
				Title("Wait").
				Value(&p.task.Wait).
				Validate(validateDate).
				Inline(true),
		),
	).
		WithShowHelp(false).
		WithShowErrors(true).
		// use styles from common
		WithHeight(40).
		WithWidth(50).
		WithTheme(p.common.Styles.Form)

	p.nFields = 6
	p.currentField = 0

	p.statusline = NewStatusLine(common, p.mode)

	return p
}

func (p *TaskEditorPage) SetSize(width, height int) {
	p.common.SetSize(width, height)
}

func (p *TaskEditorPage) Init() tea.Cmd {
	return p.form.Init()
}

func (p *TaskEditorPage) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmds []tea.Cmd

	switch msg := msg.(type) {
	case SwitchModeMsg:
		switch Mode(msg) {
		case ModeNormal:
			p.mode = ModeNormal
		case ModeInsert:
			p.mode = ModeInsert
		}
	}
	switch p.mode {
	case ModeNormal:
		switch msg := msg.(type) {
		case tea.KeyMsg:
			switch {
			case key.Matches(msg, p.common.Keymap.Back):
				model, err := p.common.PopPage()
				if err != nil {
					slog.Error("page stack empty")
					return nil, tea.Quit
				}
				return model, BackCmd
			case key.Matches(msg, p.common.Keymap.Insert):
				return p, p.switchModeCmd(ModeInsert)
			case key.Matches(msg, p.common.Keymap.Ok):
				p.form.State = huh.StateCompleted
			case key.Matches(msg, p.common.Keymap.Down):
				p.form.NextField()
			case key.Matches(msg, p.common.Keymap.Up):
				p.form.PrevField()
			}
		}
	case ModeInsert:
		switch msg := msg.(type) {
		case tea.KeyMsg:
			switch {
			case key.Matches(msg, p.common.Keymap.Back):
				return p, p.switchModeCmd(ModeNormal)
			}
		}

		f, cmd := p.form.Update(msg)
		if f, ok := f.(*huh.Form); ok {
			p.form = f
			cmds = append(cmds, cmd)
		}

	}

	var cmd tea.Cmd
	p.statusline, cmd = p.statusline.Update(msg)
	cmds = append(cmds, cmd)

	if p.form.State == huh.StateCompleted {
		cmds = append(cmds, p.updateTasksCmd)
		model, err := p.common.PopPage()
		if err != nil {
			slog.Error("page stack empty")
			return nil, tea.Quit
		}
		return model, tea.Batch(cmds...)
	}

	return p, tea.Batch(cmds...)
}

func (p *TaskEditorPage) View() string {
	return lipgloss.JoinVertical(
		lipgloss.Left,
		// lipgloss.Place(p.common.Width(), p.common.Height()-1, 0.5, 0.5, p.form.View(), lipgloss.WithWhitespaceBackground(p.common.Styles.Warning.GetForeground())),
		lipgloss.Place(p.common.Width(), p.common.Height()-1, 0.5, 0.5, p.form.View(), lipgloss.WithWhitespaceChars(" . ")),
		p.statusline.View(),
	)
}

func (p *TaskEditorPage) updateTasksCmd() tea.Msg {
	if p.task.Project == "(none)" {
		p.task.Project = ""
	}
	if p.task.Priority == "(none)" {
		p.task.Priority = ""
	}
	if p.additionalTags != "" {
		p.task.Tags = append(p.task.Tags, strings.Split(p.additionalTags, " ")...)
	}
	if p.additionalProject != "" {
		p.task.Project = p.additionalProject
	}
	// tags := p.form.Get("tags").([]string)
	// p.task.Tags = tags
	p.common.TW.ImportTask(&p.task)
	return UpdatedTasksMsg{}
}

func (p *TaskEditorPage) switchModeCmd(mode Mode) tea.Cmd {
	return func() tea.Msg {
		return SwitchModeMsg(mode)
	}
}

type UpdatedTasksMsg struct{}
type SwitchModeMsg Mode

type StatusLine struct {
	common *common.Common
	mode   Mode
	input  textinput.Model
}

func NewStatusLine(common *common.Common, mode Mode) *StatusLine {
	input := textinput.New()
	input.Placeholder = ""
	input.Prompt = ""
	input.Blur()

	return &StatusLine{
		input:  textinput.New(),
		common: common,
		mode:   mode,
	}
}

func (s *StatusLine) Init() tea.Cmd {
	s.input.Blur()
	return nil
}

func (s *StatusLine) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmd tea.Cmd

	switch msg := msg.(type) {
	case SwitchModeMsg:
		s.mode = Mode(msg)
		switch s.mode {
		case ModeNormal:
			s.input.Blur()
		case ModeInsert:
			s.input.Focus()
		}
	case tea.KeyMsg:
		switch {
		case key.Matches(msg, s.common.Keymap.Back):
			s.input.Blur()
		case key.Matches(msg, s.common.Keymap.Input):
			s.input.Focus()
		}
	}

	s.input, cmd = s.input.Update(msg)
	return s, cmd
}

func (s *StatusLine) View() string {
	var mode string
	switch s.mode {
	case ModeNormal:
		mode = s.common.Styles.Main.Render("NORMAL")
	case ModeInsert:
		mode = s.common.Styles.Active.Inline(true).Render("INSERT")
	}
	return lipgloss.JoinHorizontal(lipgloss.Left, mode, s.input.View())
}

// TODO: move this to taskwarrior; add missing date formats
func validateDate(s string) error {
	formats := []string{
		"2006-01-02",
		"2006-01-02T15:04",
		"20060102T150405Z",
	}

	otherFormats := []string{
		"",
		"now",
		"today",
		"sod",
		"eod",
		"yesterday",
		"tomorrow",
		"monday",
		"tuesday",
		"wednesday",
		"thursday",
		"friday",
		"saturday",
		"sunday",
		"mon",
		"tue",
		"wed",
		"thu",
		"fri",
		"sat",
		"sun",
		"soy",
		"eoy",
		"soq",
		"eoq",
		"som",
		"eom",
		"socm",
		"eocm",
		"sow",
		"eow",
		"socw",
		"eocw",
		"soww",
		"eoww",
		"1st",
		"2nd",
		"3rd",
		"4th",
		"5th",
		"6th",
		"7th",
		"8th",
		"9th",
		"10th",
		"11th",
		"12th",
		"13th",
		"14th",
		"15th",
		"16th",
		"17th",
		"18th",
		"19th",
		"20th",
		"21st",
		"22nd",
		"23rd",
		"24th",
		"25th",
		"26th",
		"27th",
		"28th",
		"29th",
		"30th",
		"31st",
	}

	for _, f := range formats {
		if _, err := time.Parse(f, s); err == nil {
			return nil
		}
	}

	for _, f := range otherFormats {
		if s == f {
			return nil
		}
	}

	return fmt.Errorf("invalid date")
}