// The main interface/implementation of the editor object
package editor

import (
	"fmt"
	"time"
	doc "timshome.page/gilo/editor/document"
	"timshome.page/gilo/gilo"
	"timshome.page/gilo/key"
	"timshome.page/gilo/terminal"
)

// ----------------------------------------------------------------------------
// !Editor
// ----------------------------------------------------------------------------

type statusMsg struct {
	message string
	created time.Time
}

type editor struct {
	screen    *terminal.Screen
	cursor    *gilo.Point
	offset    *gilo.Point
	document  *doc.Document
	status    *statusMsg
	quitTimes uint8
	renderX   int
}

func NewEditor() *editor {
	screen := terminal.Size()

	// Subtract rows for status bar and message bar/prompt
	screen.Rows -= 2

	cursor := gilo.DefaultPoint()
	offset := gilo.DefaultPoint()
	document := doc.NewDocument()
	status := &statusMsg{
		"",
		time.Now(),
	}

	return &editor{
		screen,
		cursor,
		offset,
		document,
		status,
		gilo.QuitTimes,
		0,
	}
}

func (e *editor) Open(filename string) {
	e.document.Open(filename)
}

func (e *editor) SetStatusMessage(template string, a ...interface{}) {
	e.status = &statusMsg{
		fmt.Sprintf(template, a...),
		time.Now(),
	}
}

func (e *editor) ProcessKeypress() bool {
	ch, _ := terminal.ReadKey()

	return e.processKeypressChar(ch)
}

func (e *editor) save() {
	if e.document.Filename == "" {
		e.document.Filename = e.prompt("Save as: %s (ESC to cancel)", nil)
		if e.document.Filename == "" {
			e.SetStatusMessage("Save aborted")
		}
	}

	size := e.document.Save()

	if size > 0 {
		e.SetStatusMessage("%d bytes written to disk", size)
	} else {
		e.SetStatusMessage("Failed to save file")
	}
}

func (e *editor) prompt(prompt string, callback func(string, string)) string {
	buf := gilo.NewBuffer()

	// Show the prompt message
	e.SetStatusMessage(prompt, "")
	e.RefreshScreen()

	for {
		if buf.Len() > 0 {
			e.SetStatusMessage(prompt, buf.ToString())
			e.RefreshScreen()
		}

		ch, _ := terminal.ReadKey()
		if ch == key.Enter {
			if buf.Len() != 0 {
				e.SetStatusMessage("")
				if callback != nil {
					callback(buf.ToString(), string(ch))
				}

				return buf.ToString()
			}
		} else if key.IsAscii(ch) && !key.IsCtrl(ch) {
			buf.AppendRune(ch)
		} else if ch == key.Backspace || ch == key.Ctrl('h') {
			buf.Truncate(buf.Len() - 1)
		} else if ch == key.Esc {
			k := parseEscapeSequence()
			if k == keyDelete {
				buf.Truncate(buf.Len() - 1)
			} else if k == string(key.Esc) {
				e.SetStatusMessage("")
				if callback != nil {
					callback(buf.ToString(), k)
				}
				return ""
			} else {
				if callback != nil {
					callback(buf.ToString(), k)
				}
			}
		}

		if callback != nil {
			callback(buf.ToString(), string(ch))
		}
	}
}

func (e *editor) find() {
	savedCursor := e.cursor.Clone()
	savedOffset := e.cursor.Clone()

	lastMatch := -1
	direction := 1
	query := e.prompt("Search: %s (Use ESC/Arrows/Enter)", func(query string, ch string) {
		if ch == string(key.Enter) || ch == string(key.Esc) {
			lastMatch = -1
			direction = 1
			return
		} else if ch == keyRight || ch == keyDown {
			direction = 1
		} else if ch == keyLeft || ch == keyUp {
			direction = -1
		} else {
			lastMatch = -1
			direction = 1
		}

		if lastMatch == -1 {
			direction = 1
		}

		current := lastMatch

		for i := 0; i < e.document.RowCount(); i++ {
			current += direction
			if current == -1 {
				current = e.document.RowCount()
			} else if current == e.document.RowCount() {
				current = 0
			}

			row := e.document.GetRow(current)
			matchIndex := row.Search(query)
			if matchIndex != -1 {
				lastMatch = current
				e.cursor.Y = current
				e.cursor.X = row.RenderXtoCursorX(matchIndex)
				e.offset.Y = e.document.RowCount()

				break
			}
		}
	})

	if query == "" {
		e.cursor = savedCursor.Clone()
		e.offset = savedOffset.Clone()

		return
	}
}

func (e *editor) insertChar(ch rune) {
	if e.cursor.Y == e.document.RowCount() {
		e.document.AppendRow("")
	}

	e.document.InsertChar(e.cursor, ch)
	e.cursor.X += 1
}

func (e *editor) delChar() {
	if e.cursor.Y == e.document.RowCount() {
		return
	}

	if e.cursor.X == 0 && e.cursor.Y == 0 {
		return
	}

	if e.cursor.X > 0 {
		at := e.cursor
		at.X -= 1
		e.document.DelChar(at)
	} else {
		// Move cursor to the current end of the previous line
		e.cursor.X = e.document.GetRow(e.cursor.Y - 1).Size()

		// Move the contents of the current row to the previous
		e.document.MergeRows(e.cursor.Y-1, e.cursor.Y)

		e.cursor.Y -= 1
	}
}