Editor for OpenComputers

--[[
Filename: open.lua
Author: quenti77

Description:

--]]

-- Require
local event = require "event"
local component = require "component"
local unicode = require "unicode"
local shell = require "shell"
local fs = require "filesystem"

-- Configuration
local config = {
    defaultColor = {
        back = 0x263238,
        front = 0xC3CEE3
    },

    menuColor = {
        bar = {
            back = 0x304047,
            front = 0xC3CEE3
        },
        quitButton = {
            back = 0xC41F1A,
            front = 0xC3CEE3
        },
        select = {
            back = 0xC7C7C7,
            front = 0x383838
        },
        sub = {
            back = 0xA1A1A1,
            front = 0x252525
        }
    },

    statusColor = {
        bar = {
            back = 0x304047,
            front = 0xC3CEE3,
            normal = 0x3A8C4C,
            updated = 0xF08C65
        }
    },

    editorColor = {
        lineNumber = {
            back = 0x34444c,
            front = 0xC3CEE3
        },
        content = {
            back = 0x263238,
            front = 0xC3CEE3
        }
    },

    modalColor = {
        background = {
            back = 0x485F6A,
            front = 0xC3CEE3
        },

        titleBar = {
            back = 0x34444c,
            front = 0xC3CEE3
        },

        textbox = {
            back = 0xF0F3F5,
            front = 0x383838
        },

        button = {
            success = {
                back = 0x00802B,
                front = 0xC3CEE3
            },
            cancel = {
                back = 0xB30000,
                front = 0xC3CEE3
            }
        }
    },

    screen = {
        width = 154,
        height = 50
    },

    screenRefresh = 0.05
}

-- Menu
local menu = {
    file = {
        x = 1,
        textX = 3,
        width = 8,
        name = "File",
        items = {
            x = 1,
            y = 2,
            width = 11,
            height = 7,
            items = {{
                x = 3,
                y = 2,
                name = "New"
            }, {
                x = 3,
                y = 3,
                name = "Open"
            }, {
                x = 1,
                y = 4,
                name = "-----------"
            }, {
                x = 3,
                y = 5,
                name = "Save"

            }, {
                x = 3,
                y = 6,
                name = "Save As"
            }, {
                x = 1,
                y = 7,
                name = "-----------"
            }, {
                x = 3,
                y = 8,
                name = "Quit"
            }}
        }
    }
}

-- Status
local status = {
    menuOpen = {
        file = false
    },

    filename = nil,
    updated = false,
    blink = false
}

-- File in editor
local files = {
    cursor = {
        line = 1,
        column = 1
    },
    content = nil,
    view = {
        top = 1,
        left = 1
    }
}

-- Modal
local modal = {
    open = false,
    value = "",
    action =  nil,
    title = ""
}

-- Other variable
local running = true
local gpu = component.gpu
local blinkConter = 0

-- Basic function
function checkPos(x, y, xmin, ymin, xmax, ymax)
    return ((x >= xmin and x <= xmax) and (y >= ymin and y <= ymax))
end

-- Display function
function clearScreen()
    gpu.setBackground(config.defaultColor.back)
    gpu.setForeground(config.defaultColor.front)
    gpu.fill(1, 1, config.screen.width, config.screen.height, " ")
end

function menuFile()
    if (status.menuOpen.file) then
        gpu.setBackground(config.menuColor.select.back)
        gpu.setForeground(config.menuColor.select.front)
        gpu.fill(menu.file.x, 1, menu.file.width, 1, " ")
        gpu.set(menu.file.textX, 1, menu.file.name)

        gpu.setBackground(config.menuColor.sub.back)
        gpu.setForeground(config.menuColor.sub.front)
        gpu.fill(menu.file.items.x, menu.file.items.y, menu.file.items.width, menu.file.items.height, " ")

        for i = 1, #menu.file.items.items do
            local item = menu.file.items.items[i]
            gpu.set(item.x, item.y, item.name)
        end
    else
        gpu.setBackground(config.menuColor.bar.back)
        gpu.setForeground(config.menuColor.bar.front)
        gpu.fill(menu.file.x, 1, menu.file.width, 1, " ")
        gpu.set(menu.file.textX, 1, menu.file.name)
    end
end

function menuScreen()
    -- Bar
    gpu.setBackground(config.menuColor.bar.back)
    gpu.setForeground(config.menuColor.bar.front)
    gpu.fill(1, 1, config.screen.width, 1, " ")

    -- X button for close app
    gpu.setBackground(config.menuColor.quitButton.back)
    gpu.setForeground(config.menuColor.quitButton.front)
    gpu.fill(config.screen.width - 2, 1, 3, 1, " ")
    gpu.set(config.screen.width - 1, 1, "×")
end

function statusScreen()
    -- Bar
    gpu.setBackground(config.statusColor.bar.back)
    gpu.setForeground(config.statusColor.bar.front)
    gpu.fill(1, config.screen.height, config.screen.width, 1, " ")

    local textRight = string.format("L: %u ¦ C: %u", files.cursor.line, files.cursor.column)
    local length = unicode.len(textRight)
    gpu.set(config.screen.width - 1 - length, config.screen.height, textRight)

    local textLeft = "Aucun fichier"
    if (status.filename ~= nil) then
        if (unicode.len(status.filename) > 50) then
            textLeft = unicode.sub(status.filename, -50)
        else
            textLeft = status.filename
        end

        gpu.setForeground(config.statusColor.bar.normal)
        if (status.updated) then
            gpu.setForeground(config.statusColor.bar.updated)
        end
    end
    gpu.set(3, config.screen.height, textLeft)
end

function editorScreen()
    local content = files.content
    local contentSize = #content
    local top = files.view.top
    local bottom = top + config.screen.height - 3

    if (bottom > contentSize) then
        bottom = contentSize
    end

    local lengthBottom = unicode.len(string.format("%u", bottom))
    local gutterWidth = lengthBottom + 2
    local width = config.screen.width - gutterWidth - 2

    gpu.setBackground(config.editorColor.lineNumber.back)
    gpu.setForeground(config.editorColor.lineNumber.front)
    gpu.fill(1, 2, gutterWidth, config.screen.height - 2, " ")

    for line = top, bottom do
        gpu.set(2 + lengthBottom - (unicode.len(string.format("%u", line))), line - top + 2, string.format("%u", line))
    end

    gpu.setBackground(config.editorColor.content.back)
    gpu.setForeground(config.editorColor.content.front)
    for line = top, bottom do
        gpu.set(gutterWidth + 2, line - top + 2, unicode.sub(content[line], files.view.left, files.view.left + width))
    end

    -- ColorCursor
    if (status.blink) then
        local t = files.cursor.line - top + 2
        local l = gutterWidth + 1 + files.cursor.column
        gpu.setBackground(config.editorColor.content.front)
        gpu.setForeground(config.editorColor.content.back)
        gpu.set(l, t, unicode.sub(files.content[files.cursor.line], files.cursor.column, files.cursor.column))
    end
end

function modalScreen()
    local x = 15
    local y = config.screen.height / 2 - 2
    local w = config.screen.width - 30
    local h = 6
    local middleW = config.screen.width / 2

    -- Modal
    gpu.setBackground(config.modalColor.background.back)
    gpu.setForeground(config.modalColor.background.front)
    gpu.fill(x, y, w, h, " ")

    -- Titlebar
    gpu.setBackground(config.modalColor.titleBar.back)
    gpu.setForeground(config.modalColor.titleBar.front)
    gpu.fill(x, y, w, 1, " ")
    gpu.set(x + 2, y, modal.title)

    gpu.setBackground(config.menuColor.quitButton.back)
    gpu.setForeground(config.menuColor.quitButton.front)
    gpu.fill(x + w - 3, y, 3, 1, " ")
    gpu.set(x + w - 2, y, "×")

    -- Textbox
    local contentTextbox = modal.value
    if (status.blink) then
        contentTextbox = contentTextbox.."|"
    end

    gpu.setBackground(config.modalColor.textbox.back)
    gpu.setForeground(config.modalColor.textbox.front)
    gpu.fill(x + 2, y + 2, w - 4, 1, " ")
    gpu.set(x + 2, y + 2, contentTextbox)

    -- Buttons
    gpu.setBackground(config.modalColor.button.success.back)
    gpu.setForeground(config.modalColor.button.success.front)
    gpu.fill(middleW - 10, y + 4, 10, 1, " ")
    gpu.set(middleW - 8, y + 4, "  Ok  ")

    gpu.setBackground(config.modalColor.button.cancel.back)
    gpu.setForeground(config.modalColor.button.cancel.front)
    gpu.fill(middleW + 2, y + 4, 10, 1, " ")
    gpu.set(middleW + 4, y + 4, "Cancel")
end

function updateScreen()
    clearScreen()
    menuScreen()
    statusScreen()

    if (files.content ~= nil) then
        editorScreen()
    end

    blinkConter = blinkConter + 1
    if (blinkConter >= 10) then
        blinkConter = 0
        status.blink = not status.blink
    end

    menuFile()

    if (modal.open) then
        modalScreen()
    end
end

function clearContent()
    if (files.content ~= nil) then
        for k, v in pairs(files.content) do
            files.content[k] = nil
        end
        files.content = nil
    end
end

function saveFile(filename)
    local f = io.open(filename, "w")

    if (f ~= nil) then
        for k, v in pairs(files.content) do
            local l = files.content[k]

            f:write(unicode.sub(l, 1, unicode.len(l) - 1).."\n")
        end
        f:close()
    end
end

function openFile(filename)
    if (unicode.sub(filename, 1, 1) ~= "/") then
        filename = "/"..filename
    end

    if (fs.exists(filename) and not fs.isDirectory(filename)) then
        local f = io.open(filename, "r")

        if (f ~= nil) then
            local l = 1

            clearContent()
            files.content = {}

            for line in f:lines() do
                files.content[l] = line.." "
                l = l + 1
            end

            f:close()

            if (#files.content == 0) then
                files.content = {" "}
            end

            files.cursor.line = 1
            files.cursor.column = 1
            files.view.top = 1
            files.view.left = 1

            status.filename = filename
        end
    end
end

function menuFileClick(item)
    local filename = ""
    if (status.filename ~= nil) then
        filename = status.filename
    end

    if (item.name == "New") then
        modal.open = true
        modal.title = "Nouveau fichier ..."
        modal.action = "new"
        modal.value = shell.getWorkingDirectory()
        status.menuOpen.file = false
    elseif (item.name == "Open") then
        modal.open = true
        modal.title = "Ouvrir un fichier ..."
        modal.action = "open"
        modal.value = shell.getWorkingDirectory()
        status.menuOpen.file = false
    elseif (item.name == "Save") then
        if (filename == "") then
            item.name = "Save As"
            menuFileClick(item)
        else
            saveFile(filename)
            status.updated = false
        end

        status.menuOpen.file = false
    elseif (item.name == "Save As") then
        modal.open = true
        modal.title = "Enregistrer sous ..."
        modal.action = "saveAs"

        if (filename == "") then
            modal.value = shell.getWorkingDirectory()
        else
            modal.value = filename
        end

        status.menuOpen.file = false
    elseif (item.name == "Quit") then
        running = false
    end
end

-- Handler event
function unknownEvent()
    --print("Unknown event called")
end

local handler = setmetatable({}, { __index = function() return unknownEvent end })

function modalTouch()
    local filename = modal.value

    if (modal.action == "new") then
        clearContent()
        files.content = {" "}
    elseif (modal.action == "open") then
        openFile(filename)
    elseif (modal.action == "saveAs") then
        saveFile(filename)
    end

    status.filename = filename
    status.updated = false
end

function handler.touch(address, x, y, button, playerName)
    if (checkPos(x, y, config.screen.width - 2, 1, config.screen.width, 1)) then
        running = false
        return true
    end

    if (not modal.open) then
        if (not status.menuOpen.file and checkPos(x, y, menu.file.x, 1, menu.file.width, 1)) then
            status.menuOpen.file = true
            return true
        end
        if (status.menuOpen.file) then
            local itemClicked

            for i = 1, #menu.file.items.items do
                local item = menu.file.items.items[i]

                if (checkPos(x, y, menu.file.items.x, item.y, menu.file.items.width, item.y)) then
                    itemClicked = item
                end
            end

            if (itemClicked ~= nil) then
                menuFileClick(itemClicked)
            else
                status.menuOpen.file = false
            end

            return true
        end

        local content = files.content
        if (content == nil) then
            return true
        end

        local contentSize = #content
        local top = files.view.top
        local bottom = top + config.screen.height - 3

        if (bottom > contentSize) then
            bottom = contentSize
        end

        local lengthBottom = unicode.len(string.format("%u", bottom))
        local gutterWidth = lengthBottom + 2
        local width = config.screen.width - gutterWidth - 2

        if (checkPos(x, y, gutterWidth + 2, 2, config.screen.width, config.screen.height - 2)) then
            local line = top + (y - 2)
            local column = x - gutterWidth - files.view.left

            if (line < 1) then
                line = 1
            end
            if (line > #files.content) then
                line = #files.content
            end

            local columnMax = unicode.len(files.content[line])
            if (column < 1) then
                column = 1
            end
            if (column > columnMax) then
                column = columnMax
            end

            files.cursor.line = line
            files.cursor.column = column

            blinkConter = 0
            status.blink = true
        end
    else
        local xStart = 15
        local yStart = config.screen.height / 2 - 2
        local w = config.screen.width - 30
        local h = 5
        local middleW = config.screen.width / 2

        -- Cancel button
        if (checkPos(x, y, middleW + 2, yStart + 4, middleW + 11, yStart + 5)) then
            modal.open = false
        end

        -- Ok button
        if (checkPos(x, y, middleW - 10, yStart + 4, middleW - 1, yStart + 5)) then
            modalTouch()
            modal.open = false
        end
    end

    return false
end

function handler.scroll(address, x, y, direction, playerName)
    if (not modal.open) then
        local newTop = files.view.top + (direction * -1)
        local maxTop = #files.content - 5

        if (newTop < 1) then
            newTop = 1
        elseif (newTop > maxTop) then
            newTop = maxTop
        end

        files.view.top = newTop
    end
end

function keyEditor(char, code)
    local line = files.cursor.line
    local column = files.cursor.column
    local direction = 0
    local updated = false

    if (files.content == nil) then
        return true
    end

    if (code == 0xC8) then
        -- up
        line = line - 1
    elseif (code == 0xCB) then
        -- left
        column = column - 1
    elseif (code == 0xD0) then
        -- down
        line = line + 1
    elseif (code == 0xCD) then
        -- right
        column = column + 1
    elseif (code == 0x2A or code == 0x36) then
        -- shift
    elseif (code == 0x1D or code == 0x9D) then
        -- ctrl
    elseif (code == 0x38 or code == 0xB8) then
        -- alt
    elseif (code == 0xC7) then
        -- home
        column = 1
    elseif (code == 0x0F) then
        -- tab
        for i = 1, 2 do
            keyEditor(string.byte(" "), 0x39)
        end

        column = column + 2
        updated = true
    elseif (code == 0xCF) then
        -- end
        column = unicode.len(files.content[line])
    elseif (code == 0x1C) then
        -- enter
        local contentLine = files.content[line]
        local saveLine = ""

        if (column > 1) then
            saveLine = unicode.sub(contentLine, 1, column - 1)
        end

        local newLine = unicode.sub(contentLine, column, unicode.len(contentLine))

        local spaces = ""
        local posChar = 1
        local charTest = unicode.sub(saveLine, posChar, posChar)

        while (charTest == " ") do
            spaces = spaces.." "
            posChar = posChar + 1
            charTest = unicode.sub(saveLine, posChar, posChar)
        end

        local countSpace = unicode.len(spaces)

        column = countSpace + 1
        files.content[line] = saveLine.." "

        line = line + 1
        table.insert(files.content, line, spaces..newLine)
        updated = true
    elseif (code == 0x0E) then
        -- backspace
        local lineContent = files.content[line]
        if (column == 1) then
            if (line == 1) then
                return true
            end
            table.remove(files.content, line)
            line = line - 1
            column = unicode.len(files.content[line])

            lineContent = unicode.sub(files.content[line], 1, unicode.len(files.content[line]) - 1)..lineContent
        else
            lineContent = unicode.sub(lineContent, 1, files.cursor.column - 2)..unicode.sub(lineContent, files.cursor.column, unicode.len(lineContent))
            column = column - 1
        end

        files.content[line] = lineContent
        updated = true
    elseif (code == 0xD3) then
        -- del
        local lineContent = files.content[line]
        local sizeLineContent = unicode.len(lineContent)

        if (column == sizeLineContent) then
            local lineDownContent = files.content[line + 1]

            if (lineDownContent ~= nil) then
                lineContent = unicode.sub(lineContent, 1, sizeLineContent - 1)
                files.content[line] = lineContent..lineDownContent
                table.remove(files.content, line + 1)
            end
        else
            local before = ""
            if (column > 1) then
                before = unicode.sub(lineContent, 1, column - 1)
            end

            local after = unicode.sub(lineContent, column + 1, sizeLineContent)
            files.content[line] = before..""..after
        end

        update = true
    else
        local lineContent = files.content[files.cursor.line]
        lineContent = unicode.sub(lineContent, 1, files.cursor.column - 1)..unicode.char(char)..unicode.sub(lineContent, files.cursor.column, unicode.len(lineContent))
        files.content[files.cursor.line] = lineContent

        column = column + 1
        updated = true
    end

    if (line < 1) then
        line = 1
    end
    if (line > #files.content) then
        line = #files.content
    end

    local columnMax = unicode.len(files.content[line])
    if (column < 1) then
        column = 1
    end
    if (column > columnMax) then
        column = columnMax
    end

    if (files.view.top > line) then
        direction = files.view.top - line
    end
    if ((files.view.top + config.screen.height - 3) < line) then
        direction = (files.view.top + config.screen.height - 3) - line
    end

    if (direction ~= 0) then
        handler.scroll(address, 0, 0, direction, playerName)
    end

    files.cursor.line = line
    files.cursor.column = column

    if (updated) then
        status.updated = true
    end
end

function keyModal(char, code)
    if (code == 0xC8) then
        -- up
    elseif (code == 0xCB) then
        -- left
    elseif (code == 0xD0) then
        -- down
    elseif (code == 0xCD) then
        -- right
    elseif (code == 0x2A or code == 0x36) then
        -- shift
    elseif (code == 0x1D or code == 0x9D) then
        -- ctrl
    elseif (code == 0x38 or code == 0xB8) then
        -- alt
    elseif (code == 0xC7) then
        -- home
    elseif (code == 0xCF) then
        -- end
    elseif (code == 0x1C) then
        -- enter
        modalTouch()
        modal.open = false
    elseif (code == 0x0E) then
        -- backspace
        modal.value = unicode.sub(modal.value, 1, unicode.len(modal.value) - 1)
    elseif (code == 0xD3) then
        -- del
    else
        modal.value = modal.value..unicode.char(char)
    end
end

function handler.key_down(address, char, code, playerName)
    if (modal.open) then
        keyModal(char, code)
    else
        keyEditor(char, code)
    end
end

function handleEvent(eventId, ...)
    if (eventId) then
        handler[eventId](...)
        --updateScreen()
    end
end

-- Start app
local args = { ... }

if (#args == 1) then
    openFile(shell.getWorkingDirectory()..args[1])
end

gpu.setResolution(config.screen.width, config.screen.height)

local timerId = event.timer(config.screenRefresh, updateScreen, math.huge)
while running do
    handleEvent(event.pull())
end

-- Stop app
event.cancel(timerId)
clearScreen()
shell.execute("clear")