"use client"

import type { ReactNode } from "react"
import { ChevronDownIcon, ChevronUpIcon } from "lucide-react"
import { Button } from "@/components/ui/button"
import { Collapsible, CollapsibleContent, CollapsibleTrigger } from "@/components/ui/collapsible"
import { cn } from "@/lib/utils"
import { fontLibrary, paletteLibrary, themeColors } from "../../../lib/theme"
import type { ColorOverrides, Palette, TemplateContent, TemplateDefinition, TemplateStyle } from "../../../lib/types"
import { Toggle } from "./toggle"

type ThemePatch = Partial<Pick<TemplateContent, "palette" | "fonts" | "colors" | "hidden" | "order" | "style">>

const colorFields: { key: keyof ColorOverrides; label: string }[] = [
    { key: "bg", label: "Hintergrund" },
    { key: "fg", label: "Text" },
    { key: "muted", label: "Nebentext" },
    { key: "surface", label: "Flächen" },
    { key: "accent", label: "Akzent" },
]

const imageOptions: { key: TemplateStyle["images"]; label: string }[] = [
    { key: "original", label: "Original" },
    { key: "mono", label: "Schwarzweiß" },
    { key: "warm", label: "Warm" },
    { key: "soft", label: "Sanft" },
    { key: "contrast", label: "Kontrast" },
]

const choice = (active: boolean) =>
    cn("cursor-pointer rounded-lg border text-left text-sm transition-shadow", active ? "ring-2 ring-ring" : "hover:border-foreground/30")

function Heading({ title, text }: { title: string; text?: string }) {
    return (
        <div className="mb-3">
            <h3 className="text-sm font-medium">{title}</h3>
            {text && <p className="mt-0.5 text-xs text-muted-foreground">{text}</p>}
        </div>
    )
}

function Swatch({ palette, active, label, onClick, small }: { palette: Palette; active: boolean; label: string; onClick: () => void; small?: boolean }) {
    return (
        <button type="button" title={label} aria-pressed={active} onClick={onClick} className={cn(choice(active), "overflow-hidden")}>
            <div className={cn("flex items-end gap-1 p-2", small ? "h-9" : "h-14")} style={{ background: palette.bg }}>
                <span className={cn("rounded-full", small ? "size-3" : "size-4")} style={{ background: palette.fg }} />
                <span className={cn("rounded-full", small ? "size-3" : "size-4")} style={{ background: palette.accent }} />
            </div>
            {!small && <p className="px-2 py-1.5 text-xs">{palette.label}</p>}
        </button>
    )
}

function More({ label, children }: { label: string; children: ReactNode }) {
    return (
        <Collapsible className="mt-2">
            <CollapsibleTrigger className="flex cursor-pointer items-center gap-1 text-xs text-muted-foreground hover:text-foreground [&[data-panel-open]>svg]:rotate-180">
                {label} <ChevronDownIcon className="size-3.5 transition-transform" />
            </CollapsibleTrigger>
            <CollapsibleContent>
                <div className="pt-3">{children}</div>
            </CollapsibleContent>
        </Collapsible>
    )
}

export function DesignPanel({ def, content, onChange }: { def: TemplateDefinition; content: TemplateContent; onChange: (patch: ThemePatch) => void }) {
    const theme = themeColors(def, content)
    const ownPalettes = new Set(def.palettes.map((p) => `${def.key}:${p.key}`))
    const ownFonts = new Set(def.fonts.map((f) => `${def.key}:${f.key}`))
    const customized = Object.values(content.colors).some(Boolean)
    const optional = content.order
        .map((key) => def.sections.find((section) => section.key === key))
        .filter((section) => section !== undefined)

    function setPalette(key: string) {
        // Neue Palette: eigene Farben zurücksetzen, sonst sieht man den Wechsel nicht
        onChange({ palette: key, colors: { bg: "", fg: "", muted: "", surface: "", accent: "" } })
    }

    function move(index: number, offset: number) {
        const keys = optional.map((section) => section.key)
        const [key] = keys.splice(index, 1)
        keys.splice(index + offset, 0, key)
        onChange({ order: keys })
    }

    return (
        <div className="flex flex-col gap-8">
            <section>
                <Heading title="Farbpalette" />
                <div className="grid grid-cols-3 gap-2">
                    {def.palettes.map((p) => (
                        <Swatch key={p.key} palette={p} label={p.label} active={content.palette === p.key} onClick={() => setPalette(p.key)} />
                    ))}
                </div>
                <More label={`Paletten aus anderen Vorlagen (${paletteLibrary.length - def.palettes.length})`}>
                    <div className="grid grid-cols-6 gap-1.5">
                        {paletteLibrary
                            .filter((entry) => !ownPalettes.has(entry.key))
                            .map((entry) => (
                                <Swatch
                                    key={entry.key}
                                    small
                                    palette={entry.palette}
                                    label={`${entry.palette.label} · ${entry.template}`}
                                    active={content.palette === entry.key}
                                    onClick={() => setPalette(entry.key)}
                                />
                            ))}
                    </div>
                </More>
            </section>

            <section>
                <Heading title="Eigene Farben" text="Zum Beispiel die Markenfarben des Kunden. Textfarbe auf dem Akzent wird automatisch gewählt." />
                <div className="grid grid-cols-5 gap-2">
                    {colorFields.map((field) => (
                        <label key={field.key} className="flex flex-col items-center gap-1.5 text-center text-[11px] text-muted-foreground">
                            <input
                                type="color"
                                value={content.colors[field.key] || theme[field.key]}
                                onChange={(event) => onChange({ colors: { ...content.colors, [field.key]: event.target.value } })}
                                className={cn("h-10 w-full cursor-pointer rounded-md border bg-transparent p-1", content.colors[field.key] && "ring-2 ring-ring")}
                            />
                            {field.label}
                        </label>
                    ))}
                </div>
                {customized && (
                    <Button variant="ghost" size="sm" className="mt-2" onClick={() => onChange({ colors: { bg: "", fg: "", muted: "", surface: "", accent: "" } })}>
                        Farben der Palette verwenden
                    </Button>
                )}
            </section>

            <section>
                <Heading title="Schriften" />
                <div className="flex flex-col gap-2">
                    {def.fonts.map((pair) => (
                        <button key={pair.key} type="button" aria-pressed={pair.key === content.fonts} onClick={() => onChange({ fonts: pair.key })} className={cn(choice(pair.key === content.fonts), "px-3 py-2.5")}>
                            {pair.label}
                        </button>
                    ))}
                </div>
                <More label={`Schriften aus anderen Vorlagen (${fontLibrary.length - def.fonts.length})`}>
                    <div className="flex max-h-72 flex-col gap-1 overflow-y-auto pr-1">
                        {fontLibrary
                            .filter((entry) => !ownFonts.has(entry.key))
                            .map((entry) => (
                                <button key={entry.key} type="button" aria-pressed={content.fonts === entry.key} onClick={() => onChange({ fonts: entry.key })} className={cn(choice(content.fonts === entry.key), "px-3 py-2")}>
                                    {entry.label} <span className="text-xs text-muted-foreground">· {entry.template}</span>
                                </button>
                            ))}
                    </div>
                </More>
            </section>

            <section>
                <Heading title="Bildstil" text="Gilt für alle Bilder der Seite." />
                <div className="flex flex-wrap gap-1.5">
                    {imageOptions.map((option) => (
                        <button
                            key={option.key}
                            type="button"
                            aria-pressed={content.style.images === option.key}
                            onClick={() => onChange({ style: { ...content.style, images: option.key } })}
                            className={cn(choice(content.style.images === option.key), "px-3 py-1.5")}
                        >
                            {option.label}
                        </button>
                    ))}
                </div>
            </section>

            <section>
                <Heading title="Bewegung" text="Dezent: nur sanftes Einblenden, keine Bewegungseffekte." />
                <div className="grid grid-cols-2 gap-1.5">
                    {(["full", "subtle"] as const).map((motion) => (
                        <button
                            key={motion}
                            type="button"
                            aria-pressed={content.style.motion === motion}
                            onClick={() => onChange({ style: { ...content.style, motion } })}
                            className={cn(choice(content.style.motion === motion), "px-3 py-2")}
                        >
                            {motion === "full" ? "Voll" : "Dezent"}
                        </button>
                    ))}
                </div>
            </section>

            <section>
                <Heading title="Sektionen" text="Reihenfolge per Pfeil ändern. Ausgeblendete Sektionen behalten ihre Inhalte." />
                <div className="flex flex-col divide-y rounded-lg border">
                    {optional.map((section, index) => (
                        <div key={section.key} className="flex items-center gap-1 pl-1">
                            <div className="flex flex-col">
                                <button type="button" aria-label={`${section.label} nach oben`} disabled={index === 0} onClick={() => move(index, -1)} className="cursor-pointer rounded p-0.5 text-muted-foreground hover:text-foreground disabled:opacity-30">
                                    <ChevronUpIcon className="size-3.5" />
                                </button>
                                <button type="button" aria-label={`${section.label} nach unten`} disabled={index === optional.length - 1} onClick={() => move(index, 1)} className="cursor-pointer rounded p-0.5 text-muted-foreground hover:text-foreground disabled:opacity-30">
                                    <ChevronDownIcon className="size-3.5" />
                                </button>
                            </div>
                            <div className="min-w-0 flex-1">
                                <Toggle
                                    checked={!content.hidden.includes(section.key)}
                                    onChange={(visible) =>
                                        onChange({ hidden: visible ? content.hidden.filter((key) => key !== section.key) : [...content.hidden, section.key] })
                                    }
                                >
                                    {section.label}
                                </Toggle>
                            </div>
                        </div>
                    ))}
                </div>
            </section>
        </div>
    )
}