conquest/src/client/views/console.nim

import strformat, strutils, times
import imguin/[cimgui, glfw_opengl, simple]
import ../utils/appImGui
import ../../common/[types]

const MAX_INPUT_LENGTH = 512
type    
    ConsoleComponent* = ref object of RootObj
        agent*: Agent
        showConsole*: bool
        inputBuffer: array[MAX_INPUT_LENGTH, char]
        console*: ConsoleItems
        history: seq[string]
        historyPosition: int 
        currentInput: string
        textSelect: ptr TextSelect

#[
    Helper functions for text selection
]#
proc getItemText(item: ConsoleItem): cstring = 
    let timestamp = item.timestamp.format("dd-MM-yyyy HH:mm:ss")
    return fmt"[{timestamp}] {$item.itemType} {item.text}".string 

proc getNumLines(data: pointer): csize_t {.cdecl.} =
    if data.isNil:
        return 0
    let console = cast[ConsoleItems](data)
    return console.items.len().csize_t

proc getLineAtIndex(i: csize_t, data: pointer, outLen: ptr csize_t): cstring {.cdecl.} =
    if data.isNil:
        return nil    
    let console = cast[ConsoleItems](data)
    let line = getItemText(console.items[i])
    if not outLen.isNil:
        outLen[] = line.len.csize_t
    return line

proc Console*(agent: Agent): ConsoleComponent =
    result = new ConsoleComponent
    result.agent = agent
    result.showConsole = true
    zeroMem(addr result.inputBuffer[0], MAX_INPUT_LENGTH)
    result.console = new ConsoleItems
    result.console.items = @[]
    result.history = @[]
    result.historyPosition = -1  
    result.currentInput = ""
    result.textSelect = textselect_create(getLineAtIndex, getNumLines, cast[pointer](result.console), 0)

#[
    Text input callback function for managing console history and autocompletion 
]#
proc callback(data: ptr ImGuiInputTextCallbackData): cint {.cdecl.} = 

    let component = cast[ConsoleComponent](data.UserData)
    
    case data.EventFlag: 
    of ImGui_InputTextFlags_CallbackHistory.int32:     
        # Handle command history using arrow-keys 

        # Store current input
        if component.historyPosition == -1: 
            component.currentInput = $(data.Buf)        

        let prev = component.historyPosition

        # Move to a new console history item
        if data.EventKey == ImGuiKey_UpArrow:
            if component.history.len() > 0:
                if component.historyPosition < 0: # We are at the current input and move to the last item in the console history
                    component.historyPosition = component.history.len() - 1 
                else: 
                    component.historyPosition = max(0, component.historyPosition - 1)

        elif data.EventKey == ImGuiKey_DownArrow: 
            if component.historyPosition != -1:
                component.historyPosition = min(component.history.len(), component.historyPosition + 1)
            
            if component.historyPosition == component.history.len(): 
                component.historyPosition = -1

        # Update the text buffer if another item was selected
        if prev != component.historyPosition: 
            let newText = if component.historyPosition == -1:
                component.currentInput
            else:
                component.history[component.historyPosition]

            # Replace text input
            data.ImGuiInputTextCallbackData_DeleteChars(0, data.BufTextLen)
            data.ImGuiInputTextCallbackData_InsertChars(0, newText.cstring, nil)

            # Set the cursor to the end of the updated input text
            data.CursorPos = newText.len().cint 
            data.SelectionStart = newText.len().cint
            data.SelectionEnd = newText.len().cint

        return 0

    of ImGui_InputTextFlags_CallbackCompletion.int32: 
        # Handle Tab-autocompletion
        discard

    else: discard
    
proc draw*(component: ConsoleComponent) =
    igBegin(fmt"[{component.agent.agentId}] {component.agent.username}@{component.agent.hostname}", addr component.showConsole, 0)
    defer: igEnd()
    
    var focusInput = false

    #[
        Console items/text section using ImGuiTextSelect in a child window
        Features: 
            - Horizontal+vertical scrolling,
            - Autoscroll
            - Colored text output
            - Text highlighting, copy/paste

        Problems I encountered with other approaches (Multi-line Text Input, TextEditor, ...):
            - https://github.com/ocornut/imgui/issues/383#issuecomment-2080346129
            - https://github.com/ocornut/imgui/issues/950
        
        Huge thanks to @dinau for implementing ImGuiTextSelect into imguin very rapidly after I requested it.
    ]#
    let consolePadding: float = 10.0f 
    let footerHeight = (consolePadding * 2) + (igGetStyle().ItemSpacing.y + igGetFrameHeightWithSpacing())
    let textSpacing = igGetStyle().ItemSpacing.x    

    # Padding 
    igDummy(vec2(0.0f, consolePadding))
    try: 
        # Set styles of the console window
        igPushStyleColor_Vec4(ImGui_Col_FrameBg.int32, vec4(0.1f, 0.1f, 0.1f, 1.0f))
        igPushStyleColor_Vec4(ImGui_Col_ScrollbarBg.int32, vec4(0.1f, 0.1f, 0.1f, 1.0f))
        igPushStyleColor_Vec4(ImGui_Col_Border.int32, vec4(0.2f, 0.2f, 0.2f, 1.0f))
        igPushStyleVar_Float(ImGui_StyleVar_FrameBorderSize .int32, 1.0f)

        let childWindowFlags = ImGuiChildFlags_NavFlattened.int32 or ImGui_ChildFlags_Borders.int32 or ImGui_ChildFlags_AlwaysUseWindowPadding.int32 or ImGuiChildFlags_FrameStyle.int32
        if igBeginChild_Str("##Console", vec2(-1.0f, -footerHeight), childWindowFlags, ImGuiWindowFlags_HorizontalScrollbar.int32):            
            # Display console items
            for entry in component.console.items:
                let timestamp = entry.timestamp.format("dd-MM-yyyy HH:mm:ss")
                igTextColored(vec4(0.6f, 0.6f, 0.6f, 1.0f), fmt"[{timestamp}]".cstring)
                igSameLine(0.0f, textSpacing)
                igTextColored(vec4(0.0f, 1.0f, 1.0f, 1.0f), $entry.itemType)
                igSameLine(0.0f, textSpacing)
                igTextUnformatted(entry.text.cstring, nil)
            
            component.textSelect.textselect_update()
  
            # Auto-scroll to bottom
            if igGetScrollY() >= igGetScrollMaxY():
                igSetScrollHereY(1.0f)
                    
    except IndexDefect:
        # CTRL+A crashes when no items are in the console
        discard
    
    finally: 
        igPopStyleColor(3)
        igPopStyleVar(1)
        igEndChild()
    
    # Padding 
    igDummy(vec2(0.0f, consolePadding))
    
    #[
        Input field with prompt indicator
    ]#
    igText(fmt"[{component.agent.agentId}]") 
    igSameLine(0.0f, textSpacing)
    
    # Calculate available width for input
    var availableWidth: ImVec2
    igGetContentRegionAvail(addr availableWidth)
    igSetNextItemWidth(availableWidth.x)
    
    let inputFlags = ImGuiInputTextFlags_EnterReturnsTrue.int32 or ImGuiInputTextFlags_EscapeClearsAll.int32 or ImGuiInputTextFlags_CallbackHistory.int32 or ImGuiInputTextFlags_CallbackCompletion.int32
    if igInputText("##Input", addr component.inputBuffer[0], MAX_INPUT_LENGTH, inputFlags, callback, cast[pointer](component)):

        let command = $(addr component.inputBuffer[0]).cstring
        let commandItem = ConsoleItem(
            timestamp: now(),
            itemType: LOG_COMMAND,
            text: command
        )
        component.console.items.add(commandItem)

        # TODO: Handle command execution
        # console.handleCommand(command)

        # Add command to console history
        component.history.add(command)
        component.historyPosition = -1 

        zeroMem(addr component.inputBuffer[0], MAX_INPUT_LENGTH)
        focusInput = true
    
    #[
        Session information (optional footer)
    ]#
    # igSeparator()
    # let sessionInfo = fmt"{component.agent.username}@{component.agent.hostname} [{component.agent.ip}]"
    # igText(sessionInfo)
    
    igSetItemDefaultFocus()
    if focusInput: 
        igSetKeyboardFocusHere(-1)