"use client"

import { MessageSquare, PanelRightOpen, Settings2, Shapes } from "lucide-react"
import { usePathname, useRouter } from "next/navigation"
import { useEffect, useRef, useState } from "react"
import {
    CanvasStage,
    DIAGRAM_FILE_ACCEPT,
} from "@/components/canvas/canvas-stage"
import {
    ChatEngineProvider,
    useChatEngine,
} from "@/components/chat/chat-engine"
import { ChatPanel } from "@/components/chat/chat-panel"
import { CompareDialog } from "@/components/chat/compare-dialog"
import { LobbyHero } from "@/components/chat/lobby-hero"
import { SaveDialog } from "@/components/save-dialog"
import { SettingsDialog } from "@/components/settings/settings-dialog"
import { TooltipProvider } from "@/components/ui/tooltip"
import { BrandMark } from "@/components/workspace/brand-mark"
import { IconButton } from "@/components/workspace/icon-button"
import { useDiagram } from "@/contexts/diagram-context"
import { useDictionary } from "@/hooks/use-dictionary"
import {
    debugCellIds,
    debugView,
    setAppShortcutHandler,
    toggleShapesPanel,
} from "@/lib/drawio/editor-bridge"
import { i18n, type Locale } from "@/lib/i18n/config"
import { modKey } from "@/lib/platform"
import { STORAGE_KEYS } from "@/lib/storage"
import { cn, isRealDiagram } from "@/lib/utils"
import { useCanvasStore } from "@/stores/canvas-store"
import { useSettingsStore } from "@/stores/settings-store"
import { useUiStore } from "@/stores/ui-store"
import { useVersionsStore } from "@/stores/versions-store"

const MOBILE_BREAKPOINT = 768
// Gap between the floating panel and the window edge
const PANEL_GAP = 12

function useIsMobile() {
    const [isMobile, setIsMobile] = useState(false)
    useEffect(() => {
        const query = window.matchMedia(
            `(max-width: ${MOBILE_BREAKPOINT - 1}px)`,
        )
        const update = () => setIsMobile(query.matches)
        update()
        query.addEventListener("change", update)
        return () => query.removeEventListener("change", update)
    }, [])
    return isMobile
}

/** Restore the language picked last time (the URL may say otherwise) */
function useSavedLocale() {
    const router = useRouter()
    const pathname = usePathname()
    useEffect(() => {
        const saved = localStorage.getItem(STORAGE_KEYS.locale)
        if (!saved || !i18n.locales.includes(saved as Locale)) return
        const parts = pathname.split("/").filter(Boolean)
        if (parts[0] === saved) return
        parts[0] = saved
        const { search, hash } = window.location
        router.replace(`/${parts.join("/")}${search}${hash}`)
    }, [])
}

// Stores on window in development, for debugging and end-to-end tests
if (typeof window !== "undefined" && process.env.NODE_ENV === "development") {
    ;(window as any).__naiStores = {
        canvas: useCanvasStore,
        versions: useVersionsStore,
        ui: useUiStore,
        settings: useSettingsStore,
        cellIds: debugCellIds,
        view: debugView,
    }
}

/** The diagram's title as a file name, or diagram-YYYY-MM-DD without one */
export function exportFilename(title: string | null): string {
    const name = (title && title !== "New Chat" ? title : "")
        .replace(/[\\/:*?"<>|]+/g, "-")
        .replace(/\s+/g, " ")
        .trim()
        .slice(0, 80)
    // Local date (toISOString would give UTC)
    return name || `diagram-${new Date().toLocaleDateString("sv-SE")}`
}

/** The whole editor: canvas, chat panel, dialogs */
export function Workspace() {
    const hydrate = useSettingsStore((s) => s.hydrate)
    useEffect(() => {
        hydrate()
    }, [hydrate])
    useSavedLocale()

    return (
        <TooltipProvider delayDuration={350}>
            <ChatEngineProvider>
                <WorkspaceLayout />
            </ChatEngineProvider>
        </TooltipProvider>
    )
}

function WorkspaceLayout() {
    const dict = useDictionary()
    const engine = useChatEngine()
    const { chartXML, saveDiagramToFile } = useDiagram()
    const isMobile = useIsMobile()
    const panelWidth = useSettingsStore((s) => s.panelWidth)
    const {
        panelOpen,
        togglePanel,
        setPanelOpen,
        mobileView,
        setMobileView,
        openSettings,
        focusComposer,
        saveDialogOpen,
        setSaveDialogOpen,
    } = useUiStore()
    const [heroDismissed, setHeroDismissed] = useState(false)
    const fileInputRef = useRef<HTMLInputElement>(null)

    // Start screen: nothing said and nothing drawn yet
    const showHero =
        engine.isRestored &&
        engine.messages.length === 0 &&
        !isRealDiagram(chartXML) &&
        !heroDismissed

    // A new conversation brings the start screen back (a new chat gets a
    // new tracing id, also when it was empty before)
    const chatId = engine.langfuseSessionId
    useEffect(() => {
        setHeroDismissed(false)
    }, [chatId])
    const messageCount = engine.messages.length
    const wasEmptyRef = useRef(true)
    useEffect(() => {
        if (messageCount > 0) wasEmptyRef.current = false
        else if (!wasEmptyRef.current) {
            wasEmptyRef.current = true
            setHeroDismissed(false)
        }
    }, [messageCount])

    // Phones: show the canvas while the AI draws and when a new version
    // lands, so the result is visible; the chat tab gets a dot meanwhile
    const isBusy = engine.isBusy
    const versionCount = useVersionsStore((s) => s.versions.length)
    const [chatUnread, setChatUnread] = useState(false)
    const lastVersionCountRef = useRef(versionCount)
    useEffect(() => {
        if (isMobile && isBusy) setMobileView("canvas")
    }, [isMobile, isBusy, setMobileView])
    useEffect(() => {
        const grew = versionCount > lastVersionCountRef.current
        lastVersionCountRef.current = versionCount
        if (isMobile && grew && engine.isRestored) {
            setMobileView("canvas")
            setChatUnread(true)
        }
    }, [versionCount, isMobile, engine.isRestored, setMobileView])
    useEffect(() => {
        if (mobileView === "chat") setChatUnread(false)
    }, [mobileView])

    // ⌘B toggles the panel; ⌘/ asks the AI about the selection; ⌘⇧K
    // shows the shape library
    useEffect(() => {
        const handle = (event: KeyboardEvent) => {
            if (!(event.metaKey || event.ctrlKey)) return false
            if (event.shiftKey && (event.key === "k" || event.key === "K")) {
                toggleShapesPanel()
                return true
            }
            if (event.key === "b" || event.key === "B") {
                if (isMobile) return false
                togglePanel()
                return true
            }
            if (event.key === "/") {
                setHeroDismissed(true)
                focusComposer()
                return true
            }
            return false
        }
        const onKeyDown = (event: KeyboardEvent) => {
            if (handle(event)) event.preventDefault()
        }
        // draw.io takes focus when it (re)loads, e.g. after a language
        // switch; Escape typed there must still close our dialogs.
        // ⌘B stays with draw.io in the canvas (bold, and ⇧ for to back).
        const handleInFrame = (event: KeyboardEvent) => {
            if (event.key === "b" || event.key === "B") return false
            if (event.key === "Escape") {
                const ui = useUiStore.getState()
                if (
                    ui.settingsOpen ||
                    ui.compareVersionId ||
                    ui.saveDialogOpen
                ) {
                    ui.setSettingsOpen(false)
                    ui.closeCompare()
                    ui.setSaveDialogOpen(false)
                    return true
                }
            }
            return handle(event)
        }
        window.addEventListener("keydown", onKeyDown)
        setAppShortcutHandler(handleInFrame)
        return () => {
            window.removeEventListener("keydown", onKeyDown)
            setAppShortcutHandler(null)
        }
    }, [isMobile, togglePanel, focusComposer])

    const openFile = () => fileInputRef.current?.click()
    const dismissHero = () => {
        setHeroDismissed(true)
        setPanelOpen(true)
    }

    const panelVisible = !isMobile && !showHero && panelOpen
    // The panel floats on the right; the canvas ends where it begins
    const canvasRight = panelVisible ? panelWidth + PANEL_GAP * 2 : 0

    return (
        <div
            className="fixed inset-0 overflow-hidden bg-canvas"
            data-testid="workspace"
        >
            {/* One canvas for both layouts: a new one would reload draw.io
                and lose its undo history */}
            <div className="absolute inset-0 flex flex-col">
                <div className="relative min-h-0 flex-1">
                    <CanvasStage
                        className={
                            isMobile
                                ? cn(
                                      "inset-0",
                                      mobileView !== "canvas" && "invisible",
                                  )
                                : "inset-y-0 left-0 transition-[right] duration-300 ease-[var(--ease-out)]"
                        }
                        style={isMobile ? undefined : { right: canvasRight }}
                        compact={isMobile}
                        hideOverlays={!isMobile && showHero}
                    />
                    {isMobile ? (
                        mobileView === "chat" &&
                        (showHero ? (
                            <div className="absolute inset-0 overflow-y-auto bg-canvas">
                                <div className="flex items-center gap-2 px-4 pt-3">
                                    <BrandMark className="size-6" />
                                    <span className="mr-auto text-[13px] font-semibold tracking-[-0.01em]">
                                        Next AI Draw.io
                                    </span>
                                    <IconButton
                                        label={dict.nav.settings}
                                        onClick={() => openSettings()}
                                        data-testid="settings-button"
                                    >
                                        <Settings2 />
                                    </IconButton>
                                </div>
                                <LobbyHero
                                    compact
                                    onOpenFile={openFile}
                                    onDrawYourself={() => {
                                        setHeroDismissed(true)
                                        setMobileView("canvas")
                                    }}
                                />
                            </div>
                        ) : (
                            <ChatPanel mobile onOpenFile={openFile} />
                        ))
                    ) : (
                        <>
                            {panelVisible && (
                                <ChatPanel onOpenFile={openFile} />
                            )}

                            {!showHero && !panelOpen && (
                                <div className="absolute top-3 right-3 z-20 flex items-center gap-1 rounded-xl bg-card p-1 shadow-float animate-fade-in">
                                    <BrandMark className="mx-0.5 size-6" />
                                    <IconButton
                                        label={dict.nav.showPanel}
                                        shortcut={`${modKey}B`}
                                        onClick={() => setPanelOpen(true)}
                                        data-testid="show-panel"
                                    >
                                        <PanelRightOpen />
                                    </IconButton>
                                </div>
                            )}

                            {showHero && (
                                <>
                                    <div className="absolute inset-0 z-10 overflow-y-auto bg-canvas">
                                        <div className="flex min-h-full items-center">
                                            <LobbyHero
                                                onOpenFile={openFile}
                                                onDrawYourself={dismissHero}
                                            />
                                        </div>
                                    </div>
                                    <div className="absolute top-3 left-3 z-20 flex items-center gap-1.5 rounded-xl bg-card py-1 pr-1 pl-1.5 shadow-float">
                                        <BrandMark className="size-6" />
                                        <span className="pr-1 text-[13px] font-semibold tracking-[-0.01em]">
                                            Next AI Draw.io
                                        </span>
                                        <IconButton
                                            label={dict.nav.settings}
                                            onClick={() => openSettings()}
                                            data-testid="settings-button"
                                        >
                                            <Settings2 />
                                        </IconButton>
                                    </div>
                                </>
                            )}
                        </>
                    )}
                </div>
                {isMobile && (
                    <nav className="flex shrink-0 items-center justify-center gap-1 border-t border-border bg-card px-3 pt-1.5 pb-[max(6px,env(safe-area-inset-bottom))]">
                        {(
                            [
                                {
                                    view: "canvas",
                                    label: dict.workspace.mobileCanvas,
                                    icon: <Shapes />,
                                },
                                {
                                    view: "chat",
                                    label: dict.workspace.mobileChat,
                                    icon: <MessageSquare />,
                                },
                            ] as const
                        ).map((item) => (
                            <button
                                key={item.view}
                                type="button"
                                onClick={() => setMobileView(item.view)}
                                aria-pressed={mobileView === item.view}
                                className={cn(
                                    "flex h-10 flex-1 items-center justify-center gap-2 rounded-xl text-[13px] text-muted-foreground [&_svg]:size-4",
                                    mobileView === item.view &&
                                        "bg-accent font-medium text-foreground",
                                )}
                            >
                                {item.icon}
                                {item.label}
                                {item.view === "chat" &&
                                    (isBusy || chatUnread) &&
                                    mobileView !== "chat" && (
                                        <span className="size-1.5 rounded-full bg-marker" />
                                    )}
                            </button>
                        ))}
                    </nav>
                )}
            </div>

            <input
                ref={fileInputRef}
                type="file"
                accept={DIAGRAM_FILE_ACCEPT}
                className="hidden"
                onChange={(event) => {
                    const file = event.target.files?.[0]
                    if (file) {
                        setHeroDismissed(true)
                        engine.openDiagramFile(file)
                    }
                    event.target.value = ""
                }}
            />

            <SettingsDialog />
            <CompareDialog />
            <SaveDialog
                open={saveDialogOpen}
                onOpenChange={setSaveDialogOpen}
                onSave={(filename, format) =>
                    saveDiagramToFile(
                        filename,
                        format,
                        engine.langfuseSessionId,
                        dict.save.savedSuccessfully,
                    )
                }
                defaultFilename={exportFilename(engine.currentTitle)}
            />
        </div>
    )
}