package editor

import (
	"fmt"
	"strings"

	"git.gophernest.net/azpect/TextEditor/internal/action"
	"git.gophernest.net/azpect/TextEditor/internal/core"
	"git.gophernest.net/azpect/TextEditor/internal/input"
	"git.gophernest.net/azpect/TextEditor/internal/style"
	tea "github.com/charmbracelet/bubbletea"
)

type Model struct {
	// Buffers
	buffers []*core.Buffer
	//next buffer id?

	// Windows
	windows        []*core.Window
	activeWindowId int

	// Editor wide state
	mode core.Mode

	// Terminal dimensions
	termWidth  int
	termHeight int

	// Input and key handling
	input *input.Handler

	// Insert mode state & repetition (applied to active window)
	insertCount  int
	insertKeys   []string
	insertAction action.Action
	lastFind     core.LastFindCommand

	// Command line state
	command              string
	commandCursor        int
	commandOutput        *core.CommandOutput
	commandHistory       []string
	commandHistoryCursor int

	// Global settings
	settings core.EditorSettings

	// Registers
	registers map[rune]core.Register // name -> register

	// Visual styles
	styles style.Styles

	// Dot operator state
	lastChangeKeys []string
}

// Model.Init: Initialize the model and start any commands that may need to run. Required
// for the bubbletea architecture.
func (m Model) Init() tea.Cmd {
	return nil
}

// Implement action.Model interface

// ==================================================
// Core Data Access
// ==================================================
func (m *Model) Windows() []*core.Window {
	return m.windows
}

func (m *Model) ActiveWindow() *core.Window {
	winId := m.activeWindowId
	for i := range m.Windows() {
		if m.windows[i].Id == winId {
			return m.windows[i]
		}
	}
	panic("Could not find window")
}

func (m *Model) Buffers() []*core.Buffer {
	return m.buffers
}

func (m *Model) SetBuffers(bufs []*core.Buffer) {
	m.buffers = bufs
}

func (m *Model) ActiveBuffer() *core.Buffer {
	win := m.ActiveWindow()
	return win.Buffer
}

// ==================================================
// Insert Mode Methods
// ==================================================
func (m *Model) InsertKeys() []string {
	return m.insertKeys
}

func (m *Model) SetInsertKeys(keys []string) {
	m.insertKeys = keys
}

func (m *Model) SetInsertRecording(count int, act action.Action) {
	m.insertCount = count
	m.insertKeys = []string{}
	m.insertAction = act
}

func (m *Model) SetLastFind(char string, forward, inclusive bool) {
	m.lastFind = core.LastFindCommand{
		Char:      char,
		Forward:   forward,
		Inclusive: inclusive,
	}
}

func (m *Model) GetLastFind() *core.LastFindCommand {
	return &m.lastFind
}

// Does update the '.' register
func (m *Model) SetLastChangeKeys(keys []string) {
	m.lastChangeKeys = keys

	m.SetRegister('.', core.CharwiseRegister, []string{strings.Join(keys, "")})
}

func (m *Model) LastChangeKeys() []string {
	return m.lastChangeKeys
}

func (m *Model) ClearLastChangeKeys() {
	m.lastChangeKeys = []string{}
}

func (m *Model) HandleKey(key string) tea.Cmd {
	return m.input.Handle(m, key)
}

func (m *Model) ExitInsertMode() {
	win := m.ActiveWindow()
	if m.insertCount > 1 {
		m.replayInsert()
	}
	if win.Cursor.Col > 0 {
		win.Cursor.Col--
	}
	m.mode = core.NormalMode
	m.insertCount = 0
	m.insertKeys = nil
}

func (m *Model) replayInsert() {
	win := m.ActiveWindow()
	buf := m.ActiveBuffer()

	// Replay (count - 1) more times
	for i := 1; i < m.insertCount; i++ {
		// For 'o' and 'O', we need to create a new line first
		switch m.insertAction.(type) {
		case action.OpenLineBelow:
			pos := win.Cursor.Line
			buf.InsertLine(pos+1, "")
			win.SetCursorLine(pos + 1)

		case action.OpenLineAbove:
			pos := win.Cursor.Line
			buf.InsertLine(pos, "")

			// 'i' and 'a' don't need setup - just replay keys
		}

		// Replay each recorded keystroke
		for _, key := range m.insertKeys {
			m.processInsertKey(key)
		}
	}
}

// TODO: Fix this shitty shit shit shit
func (m *Model) processInsertKey(key string) {
	win := m.ActiveWindow()
	buf := m.ActiveBuffer()

	col := win.Cursor.Col
	line := win.Cursor.Line
	l := buf.Line(line)

	switch key {
	case "enter":
		if col == len(l) {
			buf.InsertLine(line+1, "")
		} else {
			buf.SetLine(line, l[:col])
			buf.InsertLine(line+1, l[col:])
		}
		win.SetCursorLine(line + 1)
		win.SetCursorCol(0)

	case "backspace":
		if col > 0 {
			buf.SetLine(line, l[:col-1]+l[col:])
			win.SetCursorCol(col - 1)
		} else if line > 0 {
			prevLine := buf.Line(line - 1)
			newCol := len(prevLine)
			buf.SetLine(line-1, prevLine+l)
			buf.DeleteLine(line)
			win.SetCursorLine(line - 1)
			win.SetCursorCol(newCol)
		}

	case "delete":
		if col == len(l) && line < buf.LineCount()-1 {
			nextLine := buf.Line(line + 1)
			buf.SetLine(line, l+nextLine)
			buf.DeleteLine(line + 1)
		} else if col < len(l) {
			buf.SetLine(line, l[:col]+l[col+1:])
		}

	case "tab":
		tabs := strings.Repeat(" ", m.Settings().TabStop)
		if col < len(l) {
			buf.SetLine(line, l[:col]+tabs+l[col:])
		} else {
			buf.SetLine(line, l+tabs)
		}
		win.SetCursorCol(col + len(tabs))

	case "up":
		if line > 0 {
			win.SetCursorLine(line - 1)
		}

	case "down":
		if line+1 < buf.LineCount() {
			win.SetCursorLine(line + 1)
		}

	case "left":
		if col > 0 {
			win.SetCursorCol(col - 1)
		} else if line > 0 {
			prevLine := buf.Line(line - 1)
			win.SetCursorCol(len(prevLine))
			win.SetCursorLine(line - 1)
		}

	case "right":
		if col < len(l) {
			win.SetCursorCol(col + 1)
		} else if line+1 < buf.LineCount() {
			win.SetCursorCol(0)
			win.SetCursorLine(line + 1)
		}

	default:
		if col < len(l) {
			buf.SetLine(line, l[:col]+key+l[col:])
		} else {
			buf.SetLine(line, l+key)
		}
		win.SetCursorCol(col + len(key))
	}
}

// ==================================================
// Command Mode State
// ==================================================
func (m *Model) Command() string {
	return m.command
}

func (m *Model) SetCommand(cmd string) {
	m.command = cmd
}

func (m *Model) CommandCursor() int {
	return m.commandCursor
}

func (m *Model) SetCommandCursor(cur int) {
	if cur < 0 {
		m.commandCursor = 0
	} else if cur >= len(m.command) {
		m.commandCursor = len(m.command)
	} else {
		m.commandCursor = cur
	}
}

func (m *Model) CommandOutput() *core.CommandOutput {
	return m.commandOutput
}

func (m *Model) SetCommandOutput(out *core.CommandOutput) {
	m.commandOutput = out
}

func (m *Model) CommandHistory() []string {
	return m.commandHistory
}

func (m *Model) SetCommandHistory(history []string) {
	m.commandHistory = history
}

func (m *Model) CommandHistoryCursor() int {
	return m.commandHistoryCursor
}

func (m *Model) SetCommandHistoryCursor(cur int) {
	m.commandHistoryCursor = cur
}

// ==================================================
// Editor-wide State
// ==================================================
func (m *Model) Mode() core.Mode {
	return m.mode
}

func (m *Model) SetMode(mode core.Mode) {
	m.mode = mode
}

func (m *Model) Settings() core.EditorSettings {
	return m.settings
}

func (m *Model) SetSettings(s core.EditorSettings) {
	m.settings = s
}

// Model.Styles: Returns the visual styles used for rendering.
func (m *Model) Styles() style.Styles {
	return m.styles
}

// Model.SetStyles: Sets the visual styles used for rendering.
func (m *Model) SetStyles(s style.Styles) {
	m.styles = s
}

// ==================================================
// Registers
// ==================================================
func (m *Model) Registers() map[rune]core.Register {
	return m.registers
}

func (m *Model) GetRegister(name rune) (core.Register, bool) {
	reg, found := m.registers[name]
	return reg, found
}

func (m *Model) SetRegister(name rune, t core.RegisterType, cnt []string) error {
	if _, found := m.GetRegister(name); !found {
		return fmt.Errorf("Register '%c' does not exist.", name)
	}

	// TODO: This might be slow, pointers maybe?
	reg := core.Register{Type: t, Content: cnt}
	m.registers[name] = reg

	return nil
}

func (m *Model) UpdateDefaultRegister(t core.RegisterType, cnt []string) {
	// Shift numbered registers: 0 -> 1 -> 2 -> ... -> 9 -> _ (discarded)
	for i := rune('9'); i > '0'; i-- {
		m.registers[i] = m.registers[i-1]
	}

	// 0 and " both hold the new content independently
	m.SetRegister('0', t, cnt)
	m.SetRegister('"', t, cnt)
}