const LOCAL_STORAGE_KEY = 'nightowl-color-scheme'
const LIGHT = 'light'
const DARK = 'dark'
let store: Storage | null = null
const persistPreference = true
let mode = LIGHT
let automaticInitialization = true
let toggleButtonMode = 'currentState'
interface NightowlOptions {
    defaultMode?: 'light' | 'dark'
    toggleButtonMode?: 'currentState' | 'newState'
}

try {
    store = localStorage
} catch (err) {
    // Do nothing. The user probably blocks cookies.
}

function loadCss() {
    // fix css loading via vite
    // https://github.com/vitejs/vite/issues/8976
    const css = document.createElement('style')
    css.innerHTML = `
    /* Prevent inconsistencies for positioning */
    .nightowl-light body{
        filter: invert(0%);
    }
    
    .nightowl-dark {
    /* Firefox fallback. */
    background-color: #111;
    }

    .nightowl-dark body {
        filter: invert(100%) hue-rotate(180deg);
    }

    /* Do not invert media (revert the invert). */
    .nightowl-dark img, .nightowl-dark video, .nightowl-dark iframe, .nightowl-dark .nightowl-daylight {
        filter: invert(100%) hue-rotate(180deg);
    }

    /* Improve contrast on icons. */
    .nightowl-dark .icon {
        filter: invert(15%) hue-rotate(180deg);
    }

    /* Re-enable code block backgrounds. */
     .nightowl-dark pre {
        filter: invert(6%);
    }

    /* Improve contrast on list item markers. */
    .nightowl-dark li::marker {
        color: #666;
    }
    `
    document.head.appendChild(css)
}

export function createNightowl(options: NightowlOptions) {
    automaticInitialization = false
    if (options.defaultMode === 'dark') {
        mode = DARK
    }
    if (options.toggleButtonMode) {
        toggleButtonMode = options.toggleButtonMode
    }
    if (document.readyState === 'complete') {
        loadCss()
        initializeNightowl()
        initializeSwitcher()
    } else {
        window.addEventListener('load', () => {
            loadCss()
            initializeNightowl()
            initializeSwitcher()
        })
    }
}

window.addEventListener('load', () => {
    if (automaticInitialization) {
        loadCss()
        initializeNightowl()
        initializeSwitcher()
    }
})

function enableDarkMode() {
    mode = DARK
    const htmlElement = document.querySelector('html')
    if (htmlElement) {
        htmlElement.classList.remove('nightowl-light')
        htmlElement.classList.add('nightowl-dark')
    }
}

function enableLightMode() {
    mode = LIGHT
    const htmlElement = document.querySelector('html')
    if (htmlElement) {
        htmlElement.classList.remove('nightowl-dark')
        htmlElement.classList.add('nightowl-light')
    }
}

function toggleMode() {
    mode = mode === DARK ? LIGHT : DARK
    updateMode()
}

function updateMode() {
    if (mode === DARK) {
        enableDarkMode()
    } else {
        enableLightMode()
    }
    setSwitcherIcon()
}

function setSwitcherIcon() {
    const switcher = document.getElementById('nightowl-switcher-default')
    if (switcher) {
        const lightIcon =
            '<svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" style="width: 25px; height:25px;">\n' +
            '  <path stroke-linecap="round" stroke-linejoin="round" d="M12 3v2.25m6.364.386l-1.591 1.591M21 12h-2.25m-.386 6.364l-1.591-1.591M12 18.75V21m-4.773-4.227l-1.591 1.591M5.25 12H3m4.227-4.773L5.636 5.636M15.75 12a3.75 3.75 0 11-7.5 0 3.75 3.75 0 017.5 0z" />\n' +
            '</svg>'
        const darkIcon =
            '<svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" style="width: 25px; height:25px;">\n' +
            '  <path stroke-linecap="round" stroke-linejoin="round" d="M21.752 15.002A9.718 9.718 0 0118 15.75c-5.385 0-9.75-4.365-9.75-9.75 0-1.33.266-2.597.748-3.752A9.753 9.753 0 003 11.25C3 16.635 7.365 21 12.75 21a9.753 9.753 0 009.002-5.998z" />\n' +
            '</svg>'

        if (toggleButtonMode === 'newState') {
            switcher.innerHTML = mode === DARK ? lightIcon : darkIcon
        } else if (toggleButtonMode === 'currentState') {
            switcher.innerHTML = mode === DARK ? darkIcon : lightIcon
        }
    }
}

function initializeSwitcher() {
    const switcher = document.createElement('div')
    console.log(window.innerWidth)
    switcher.id = 'nightowl-switcher-default'
    switcher.style.position = 'fixed'
    switcher.style.left = 'calc(100vw - 100px)'
    switcher.style.top = 'calc(10px)'
    switcher.style.width = '50px'
    switcher.style.height = '50px'
    switcher.style.borderRadius = '50%'
    switcher.style.backgroundColor =
        toggleButtonMode === 'newState' ? 'black' : 'white'
    switcher.style.display = 'flex'
    switcher.style.justifyContent = 'center'
    switcher.style.alignItems = 'center'
    switcher.style.cursor = 'pointer'
    switcher.style.zIndex = '9999'
    switcher.style.boxShadow = '0 0 10px rgba(0,0,0,0.2)'
    switcher.style.transition = 'all 0.3s ease-in-out'
    switcher.style.overflow = 'hidden'
    switcher.style.color = toggleButtonMode === 'newState' ? 'white' : 'black'

    switcher.addEventListener('click', () => {
        toggleMode()
        storeModeInLocalStorage()
    })

    document.body.appendChild(switcher)
    setSwitcherIcon()
}

function initializeColorSchemeChangeListener() {
    // window.matchMedia('(prefers-color-scheme: dark)').addEventListener('change', e => {
    //     const newColorScheme = e.matches ? "dark" : "light";
    // });
}

function checkForRememberedValue() {
    let rememberedValue = null
    try {
        if (store) {
            rememberedValue = store.getItem(LOCAL_STORAGE_KEY)
        }
    } catch (err) {
        // Do nothing. The user probably blocks cookies.
    }

    if (rememberedValue && [DARK, LIGHT].includes(rememberedValue)) {
        mode = rememberedValue
    } else if (hasNativeDarkPrefersColorScheme()) {
        mode = DARK
    }
}

function initializeNightowl() {
    initializeColorSchemeChangeListener()

    checkForRememberedValue()

    updateMode()
}

function storeModeInLocalStorage() {
    if (persistPreference && mode !== null) {
        try {
            if (store) {
                store.setItem(LOCAL_STORAGE_KEY, mode)
            }
        } catch (err) {
            // Do nothing. The user probably blocks cookies.
        }
    }
}

function hasNativeDarkPrefersColorScheme() {
    return (
        window.matchMedia &&
        (window.matchMedia('(prefers-color-scheme: dark)').matches ||
            window.matchMedia('(prefers-color-scheme:dark)').matches)
    )
}