/** Script used in the commandline iframe. Communicates with background. */

import * as Messaging from './messaging'
import * as SELF from './commandline_frame'
import './number.clamp'
import state from './state'

let completions = window.document.getElementById("completions") as HTMLElement
let clInput = window.document.getElementById("tridactyl-input") as HTMLInputElement

export let focus = () => clInput.focus()

async function sendExstr(exstr) {
    Messaging.message("commandline_background", "recvExStr", [exstr])
}



/* Process the commandline on enter. */
clInput.addEventListener("keydown", function (keyevent) {
    switch (keyevent.key) {
        case "Enter":
            process()
            break

        case "Escape":
            hide_and_clear()
            break

        // Todo: fish-style history search
        // persistent history
        case "ArrowUp":
            history(-1)
            break

        case "ArrowDown":
            history(1)
            break

        // Clear input on ^C
        // Todo: hard mode: vi style editing on cli, like set -o mode vi
        // should probably just defer to another library
        case "c":
            if (keyevent.ctrlKey) hide_and_clear()

    }
})

let cmdline_history_position = 0
let cmdline_history_current = ""

function hide_and_clear(){
    /** Bug workaround: clInput cannot be cleared during an "Escape"
     * keydown event, presumably due to Firefox's internal handler for
     * Escape. So clear clInput just after :)
     */
    completions.innerHTML = ""
    setTimeout(()=>{clInput.value = ""}, 0)
    sendExstr("hidecmdline")
}

function history(n){
    completions.innerHTML = ""
    if (cmdline_history_position == 0){
        cmdline_history_current = clInput.value 
    }
    let wrapped_ind = state.cmdHistory.length + n - cmdline_history_position
    wrapped_ind = wrapped_ind.clamp(0, state.cmdHistory.length)

    const pot_history = state.cmdHistory[wrapped_ind]
    clInput.value = pot_history == undefined ? cmdline_history_current : pot_history
    cmdline_history_position = cmdline_history_position - n
}

/* Send the commandline to the background script and await response. */
function process() {
    console.log(clInput.value)
    sendExstr("hidecmdline")
    sendExstr(clInput.value)
    if (! browser.extension.inIncognitoContext) {
        state.cmdHistory = state.cmdHistory.concat([clInput.value])
    }
    console.log(state.cmdHistory)
    completions.innerHTML = ""
    clInput.value = ""
    cmdline_history_position = 0
}

export function fillcmdline(newcommand?: string){
    if (newcommand != "") {
        clInput.value = newcommand + " "
    }
    // Focus is lost for some reason.
    focus()
}

export function changecompletions(newcompletions: string) {
    completions.innerHTML = newcompletions
}

function applyWithTmpTextArea(fn) {
    let textarea
    try {
        textarea = document.createElement("textarea")
        // Scratchpad must be `display`ed, but can be tiny and invisible.
        // Being tiny and invisible means it won't make the parent page move.
        textarea.style.cssText = 'visible: invisible; width: 0; height: 0; position: fixed'
        textarea.contentEditable = "true"
        document.documentElement.appendChild(textarea)
        return fn(textarea)
    } finally {
        document.documentElement.removeChild(textarea)
    }
}

export function setClipboard(content: string) {
    return applyWithTmpTextArea(scratchpad => {
        scratchpad.value = content
        scratchpad.select()
        if (document.execCommand("Copy")) {
            // // todo: Maybe we can consider to using some logger and show it with status bar in the future
            console.log('set clipboard:', scratchpad.value)
        } else throw "Failed to copy!"
    })
}

export function getClipboard() {
    return applyWithTmpTextArea(scratchpad => {
        scratchpad.focus()
        document.execCommand("Paste")
        console.log('get clipboard', scratchpad.textContent)
        return scratchpad.textContent
    })
}

Messaging.addListener('commandline_frame', Messaging.attributeCaller(SELF))