// modules/admin/pages/assets/AddAsset.jsx

import { useState, useRef } from "react";
import { Link, useNavigate } from "react-router-dom";
import { useForm, Controller } from "react-hook-form";
import { z } from "zod";
import { zodResolver } from "@hookform/resolvers/zod";
import { ArrowLeft, ArrowRight, UploadCloud, X, FileVideo, FileText, Image, FileAudio } from "lucide-react";

import { useAssets } from "@/contexts/AdminAssetsContext";
import { useAuth } from "@/contexts/AuthContext";
import { MAX_ASSET_FILE_SIZE_SINGLE, MAX_ASSET_FILE_SIZE_SINGLE_LABEL } from "@/utils/assetUpload.util";
import { formatFileSize } from "@/utils/format.util";
import { useUnsavedChangesGuard } from "@/hooks/useUnsavedChangesGuard";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import { Spinner } from "@/components/ui/spinner";
import { Progress } from "@/components/ui/progress";
import {
    Select,
    SelectContent,
    SelectItem,
    SelectTrigger,
    SelectValue,
} from "@/components/ui/select";

// ─── Derive file_type from MIME type ──────────────────────────────────────────

function resolveFileType(mimeType = "") {
    if (mimeType.startsWith("video/"))  return "video";
    if (mimeType.startsWith("image/"))  return "image";
    if (mimeType.startsWith("audio/"))  return "audio";
    if (mimeType.startsWith("application/") || mimeType.startsWith("text/")) return "document";
    return "document";
}

// ─── Schema ───────────────────────────────────────────────────────────────────

const schema = z.object({
    display_name:     z.string().min(1, "Display name is required."),
    description:      z.string().optional(),
    is_public:        z.enum(["true", "false"]),
    storage_provider: z.enum(["chibisafe", "local", "s3"]),
});

// ─── File type icon ───────────────────────────────────────────────────────────

function FileTypeIcon({ mimeType = "" }) {
    if (mimeType.startsWith("video/")) return <FileVideo className="h-10 w-10 text-blue-400" />;
    if (mimeType.startsWith("image/")) return <Image className="h-10 w-10 text-green-400" />;
    if (mimeType.startsWith("audio/")) return <FileAudio className="h-10 w-10 text-purple-400" />;
    return <FileText className="h-10 w-10 text-orange-400" />;
}

// ─── Drop zone ────────────────────────────────────────────────────────────────

function DropZone({ label, accept, file, onFile, onClear, error }) {
    const inputRef = useRef(null);

    return (
        <div
            onDragOver={(e) => e.preventDefault()}
            onDrop={(e) => { e.preventDefault(); const f = e.dataTransfer.files[0]; if (f) onFile(f); }}
            onClick={() => !file && inputRef.current?.click()}
            className={[
                "rounded-lg border-2 border-dashed transition-colors cursor-pointer",
                error ? "border-destructive/60 bg-destructive/5" : "",
                file ? "border-border bg-muted/30 cursor-default" : "",
                !file && !error ? "border-muted-foreground/30 hover:border-primary/50 hover:bg-muted/20" : "",
            ].join(" ")}
        >
            <input
                ref={inputRef}
                type="file"
                accept={accept}
                className="hidden"
                onChange={(e) => { if (e.target.files[0]) onFile(e.target.files[0]); }}
            />
            {file ? (
                <div className="flex items-center gap-3 p-4">
                    <FileTypeIcon mimeType={file.type} />
                    <div className="flex-1 min-w-0">
                        <p className="text-sm font-medium truncate">{file.name}</p>
                        <p className="text-xs text-muted-foreground">
                            {formatFileSize(file.size)} · {file.type}
                        </p>
                    </div>
                    <Button
                        type="button" variant="ghost" size="icon"
                        onClick={(e) => { e.stopPropagation(); onClear(); }}
                    >
                        <X className="h-4 w-4" />
                    </Button>
                </div>
            ) : (
                <div className="flex flex-col items-center justify-center gap-2 py-10 px-4">
                    <UploadCloud className="h-8 w-8 text-muted-foreground/50" />
                    <p className="text-sm text-muted-foreground text-center">
                        Drag & drop or <span className="text-primary font-medium">browse</span> to upload
                        <br />
                        <span className="text-xs">{label}</span>
                    </p>
                </div>
            )}
        </div>
    );
}

// ─── Field error ──────────────────────────────────────────────────────────────

function FieldError({ message }) {
    if (!message) return null;
    return <p className="text-xs text-destructive mt-1">{message}</p>;
}

// ─── Page ─────────────────────────────────────────────────────────────────────

export default function AddAsset() {
    const navigate = useNavigate();
    const { uploadAsset, loading } = useAssets();
    const { user } = useAuth();

    const fileRef      = useRef(null);
    const thumbnailRef = useRef(null);
    const [thumbKey, setThumbKey] = useState(0);
    const [progress, setProgress] = useState(null); // { phase: 'uploading'|'processing'|'done'|'error', pct } | null

    const {
        register,
        control,
        handleSubmit,
        setValue,
        watch,
        setError,
        clearErrors,
        formState: { errors, isDirty },
    } = useForm({
        resolver: zodResolver(schema),
        defaultValues: {
            display_name:     "",
            description:      "",
            is_public:        "false",
            storage_provider: "s3", // ← changed from "chibisafe"
        },
    });

    const file    = watch("_file");
    const isVideo = file?.type?.startsWith("video/");
    const isAudio = file?.type?.startsWith("audio/");

    // setValue("_file", ...) doesn't mark isDirty (no shouldDirty), so a
    // picked-but-unsubmitted file wouldn't otherwise be caught by the guard.
    const { bypassOnce, dialog: unsavedChangesDialog } = useUnsavedChangesGuard(isDirty || !!file);

    // ── Auto-derive file_type from MIME ───────────────────────────────────────
    const fileType = file ? resolveFileType(file.type) : null;

    const setFile = (f) => {
        if (f.size > MAX_ASSET_FILE_SIZE_SINGLE) {
            setError("_file", { message: `File exceeds the ${MAX_ASSET_FILE_SIZE_SINGLE_LABEL} size limit.` });
            return;
        }
        fileRef.current = f;
        setValue("_file", f);
        if (!watch("display_name")) setValue("display_name", f.name);
        clearErrors("_file");
    };

    const setThumbnail = (f) => {
        thumbnailRef.current = f;
        setValue("_thumbnail", f);
        clearErrors("_thumbnail");
    };

    const onSubmit = async (data) => {
        let hasFileError = false;

        if (!fileRef.current) {
            setError("_file", { message: "A file is required." });
            hasFileError = true;
        }

        if (hasFileError) return;

        setProgress({ phase: "uploading", pct: 0 });
        const result = await uploadAsset({
            file:             fileRef.current,
            thumbnail:        thumbnailRef.current ?? undefined,
            display_name:     data.display_name,
            description:      data.description ?? "",
            file_type:        fileType,
            is_public:        data.is_public === "true",
            storage_provider: data.storage_provider,
            createdBy:        user?.user_id,
            onProgress:       setProgress,
        });
        setProgress(null);

        if (result) { bypassOnce(); navigate("/admin/assets"); }
    };

    const progressLabel = {
        uploading:  "Uploading…",
        processing: "Processing…",
        done:       "Done.",
        error:      "Upload failed.",
    }[progress?.phase];

    return (
        <div className="max-w-2xl mx-auto px-4 py-6 space-y-6">

            {/* ── Header ── */}
            <div className="flex items-center gap-3">
                <Button type="button" variant="ghost" size="icon" onClick={() => navigate("/admin/assets")}>
                    <ArrowLeft className="h-4 w-4" />
                </Button>
                <div>
                    <h1 className="text-xl font-semibold">Add Asset</h1>
                    <p className="text-sm text-muted-foreground">Upload a new file to the asset library.</p>
                </div>
            </div>

            <form onSubmit={handleSubmit(onSubmit)} className="space-y-6">
                <div className="rounded-lg border bg-card p-6 space-y-5">

                    {/* ── File ── */}
                    <div className="space-y-1.5">
                        <Label>File <span className="text-destructive">*</span></Label>
                        <DropZone
                            label="Images, videos, audio, documents"
                            accept="image/*,video/*,audio/*,application/*,text/*"
                            file={fileRef.current}
                            onFile={setFile}
                            onClear={() => {
                                fileRef.current = null;
                                setValue("_file", null);
                                setValue("display_name", "");
                                clearErrors("_file");
                            }}
                            error={errors._file?.message}
                        />
                        <FieldError message={errors._file?.message} />
                        <Link
                            to="/admin/assets/add/bulk"
                            className="inline-flex items-center gap-1 text-xs text-primary hover:underline"
                        >
                            Uploading multiple files? Use Bulk Upload <ArrowRight className="h-3 w-3" />
                        </Link>
                    </div>

                    {/* ── Thumbnail (optional for both video and audio) ── */}
                    {(isVideo || isAudio) && (
                        <div className="space-y-1.5">
                            <Label>
                                Thumbnail{" "}
                                <span className="text-muted-foreground text-xs">
                                    (optional — {isVideo ? "video preview" : "album / cover art"})
                                </span>
                            </Label>
                            <DropZone
                                key={thumbKey}
                                label="JPEG, PNG"
                                accept="image/*"
                                file={thumbnailRef.current}
                                onFile={setThumbnail}
                                onClear={() => {
                                    thumbnailRef.current = null;
                                    setValue("_thumbnail", null);
                                    clearErrors("_thumbnail");
                                    setThumbKey((k) => k + 1);
                                }}
                                error={errors._thumbnail?.message}
                            />
                            <FieldError message={errors._thumbnail?.message} />
                        </div>
                    )}

                    {/* ── Display Name ── */}
                    <div className="space-y-1.5">
                        <Label htmlFor="display_name">
                            Display Name <span className="text-destructive">*</span>
                        </Label>
                        <Input
                            id="display_name"
                            placeholder="Friendly name for this asset"
                            {...register("display_name")}
                        />
                        <FieldError message={errors.display_name?.message} />
                    </div>

                    {/* ── Description ── */}
                    <div className="space-y-1.5">
                        <Label htmlFor="description">Description</Label>
                        <Textarea
                            id="description"
                            placeholder="Optional description"
                            rows={3}
                            {...register("description")}
                        />
                    </div>

                    {/* ── File Type · Access · Storage (one row) ── */}
                    <div className="grid grid-cols-3 gap-4">

                        {/* File Type — auto-derived, disabled */}
                        <div className="space-y-1.5">
                            <Label>File Type</Label>
                            <Select value={fileType ?? ""} disabled>
                                <SelectTrigger className="disabled:opacity-60 disabled:cursor-not-allowed">
                                    <SelectValue placeholder="Auto-detected" />
                                </SelectTrigger>
                                <SelectContent>
                                    <SelectItem value="avatar">Avatar</SelectItem>
                                    <SelectItem value="image">Image</SelectItem>
                                    <SelectItem value="video">Video</SelectItem>
                                    <SelectItem value="audio">Audio</SelectItem>
                                    <SelectItem value="document">Document</SelectItem>
                                </SelectContent>
                            </Select>
                            <p className="text-xs text-muted-foreground">Detected from file</p>
                        </div>

                        {/* Access */}
                        <div className="space-y-1.5">
                            <Label>Access</Label>
                            <Controller
                                name="is_public"
                                control={control}
                                render={({ field }) => (
                                    <Select value={field.value} onValueChange={field.onChange}>
                                        <SelectTrigger><SelectValue /></SelectTrigger>
                                        <SelectContent>
                                            <SelectItem value="false">Private</SelectItem>
                                            <SelectItem value="true">Public</SelectItem>
                                        </SelectContent>
                                    </Select>
                                )}
                            />
                        </div>

                        {/* Storage Provider — TEMPORARY: locked to S3 (see zrok tunnel note above; revert after VPS migration) */}
                        <div className="space-y-1.5">
                            <Label>Storage</Label>
                            <Select value="s3" disabled>
                                <SelectTrigger className="disabled:opacity-60 disabled:cursor-not-allowed"><SelectValue /></SelectTrigger>
                                <SelectContent>
                                    <SelectItem value="s3">S3</SelectItem>
                                </SelectContent>
                            </Select>
                        </div>

                    </div>

                </div>

                {/* ── Upload progress (real — see AdminAssetsContext.uploadAsset) ── */}
                {progress && (
                    <div className="space-y-1.5">
                        <div className="flex items-center justify-between text-xs text-muted-foreground">
                            <span>{progressLabel}</span>
                            <span>{progress.pct ?? 0}%</span>
                        </div>
                        <Progress value={progress.pct ?? 0} />
                    </div>
                )}

                {/* ── Actions ── */}
                <div className="flex justify-end gap-3">
                    <Button
                        type="button"
                        variant="outline"
                        onClick={() => navigate("/admin/assets")}
                        disabled={loading}
                    >
                        Cancel
                    </Button>
                    <Button type="submit" disabled={loading}>
                        {loading && <Spinner className="h-4 w-4 mr-2" />}
                        Upload Asset
                    </Button>
                </div>
            </form>

            {unsavedChangesDialog}
        </div>
    );
}