"use client";

import { useState, useRef, useEffect, useMemo } from "react";
import { Upload, X, Loader2 } from "lucide-react";
import { Button } from "@/components/ui/button";
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog";
import { useToast } from "@/hooks/use-toast";
import { validateFileForUpload, generateFilePreview } from "@/lib/file-utils";
import { COMIC_STYLES } from "@/lib/constants";

interface PageReference {
  pageNumber: number;
  characterImages: string[];
  prompt: string;
  imageUrl?: string;
  style: string;
}

interface GeneratePageModalProps {
  isOpen: boolean;
  onClose: () => void;
  onGenerate: (data: {
    prompt: string;
    style: string;
    characterFiles?: File[];
    characterUrls?: string[];
    isContinuation?: boolean;
  }) => void;
  pageNumber: number;
  allPages: PageReference[];
}

export function GeneratePageModal({
  isOpen,
  onClose,
  onGenerate,
  pageNumber,
  allPages,
}: GeneratePageModalProps) {
  const [prompt, setPrompt] = useState("");
  const [uploadedFiles, setUploadedFiles] = useState<File[]>([]);
  const [selectedExistingCharacters, setSelectedExistingCharacters] = useState<
    string[]
  >([]);
  const [referencePageNumber, setReferencePageNumber] = useState<number>(
    allPages.length > 0 ? allPages.length : 1
  );
  const [pageImage, setPageImage] = useState<string | null>(null);
  const [previews, setPreviews] = useState<string[]>([]);
  const [showPreview, setShowPreview] = useState<number | null>(null);
  const [isGenerating, setIsGenerating] = useState(false);
  const fileInputRef = useRef<HTMLInputElement>(null);
  const { toast } = useToast();

  const referencePage =
    allPages.find((p) => p.pageNumber === referencePageNumber) || null;
  const referenceStyleId = referencePage?.style || "noir";
  const selectedStyleName =
    COMIC_STYLES.find((s) => s.id === referenceStyleId)?.name || "Noir";
  const selectedStyle = useMemo(() => selectedStyleName, [referenceStyleId]);

  useEffect(() => {
    if (isOpen && referencePage) {
      setSelectedExistingCharacters(referencePage.characterImages);
      setPageImage(referencePage.imageUrl || null);
    } else if (isOpen && !referencePage) {
      setPageImage(null);
    }
  }, [isOpen, referencePage]);

  const handleFiles = async (newFiles: FileList | null) => {
    if (!newFiles) return;

    const filesArray = Array.from(newFiles);

    const validationResults = filesArray.map((file) => ({
      file,
      validation: validateFileForUpload(file, true),
    }));

    validationResults.forEach(({ validation }) => {
      if (!validation.valid && validation.error) {
        toast({
          title: "Invalid file",
          description: validation.error,
          variant: "destructive",
          duration: 4000,
        });
      }
    });

    const validFiles = validationResults
      .filter(({ validation }) => validation.valid)
      .map(({ file }) => file);

    if (validFiles.length === 0) return;

    const totalFiles = [...uploadedFiles, ...validFiles].slice(0, 2);
    setUploadedFiles(totalFiles);

    const newPreviews = await Promise.all(
      totalFiles.map((file) => generateFilePreview(file))
    );
    setPreviews(newPreviews);
  };

  const removeFile = (index: number) => {
    const newFiles = uploadedFiles.filter((_, i) => i !== index);
    const newPreviews = previews.filter((_, i) => i !== index);
    setUploadedFiles(newFiles);
    setPreviews(newPreviews);
    setShowPreview(null);
    if (fileInputRef.current) {
      fileInputRef.current.value = "";
    }
  };

  const toggleExistingCharacter = (characterUrl: string) => {
    setSelectedExistingCharacters((prev) =>
      prev.includes(characterUrl)
        ? prev.filter((url) => url !== characterUrl)
        : [...prev, characterUrl]
    );
  };

  const togglePageImage = () => {
    setPageImage((prev) =>
      prev === null && referencePage?.imageUrl ? referencePage.imageUrl : null
    );
  };

  const handleGenerate = async () => {
    if (!prompt.trim()) return;
    setIsGenerating(true);

    const fileDataUrls = await Promise.all(
      uploadedFiles.map((file, index) => {
        return new Promise<string>((resolve) => {
          const reader = new FileReader();
          reader.onload = (e) => {
            const base64 = e.target?.result as string;
            const [header, base64Data] = base64.split(",");
            // Send just the base64 data without the data URL prefix
            resolve(base64Data);
          };
          reader.readAsDataURL(file);
        });
      })
    );

    const allCharacterUrls: string[] = [
      ...selectedExistingCharacters,
      ...fileDataUrls,
      ...(pageImage ? [pageImage] : []),
    ];

    onGenerate({
      prompt,
      style: selectedStyle,
      characterFiles: uploadedFiles.length > 0 ? uploadedFiles : undefined,
      characterUrls: allCharacterUrls,
      isContinuation: false,
    });
  };

  useEffect(() => {
    if (!isOpen) {
      setIsGenerating(false);
      setPrompt("");
      setUploadedFiles([]);
      setSelectedExistingCharacters([]);
      setPageImage(null);
      if (allPages.length > 0) {
        setReferencePageNumber(allPages.length);
      }
    }
  }, [isOpen]);

  return (
    <>
      <Dialog open={isOpen} onOpenChange={onClose}>
        <DialogContent className="border border-border/50 rounded-lg bg-background max-w-lg">
          <DialogHeader>
            <DialogTitle className="text-xl text-white font-heading">
              Generate Page {pageNumber}
            </DialogTitle>
          </DialogHeader>

          <div className="space-y-4 mt-4">
            {/* Reference Page Selection */}
            {allPages.length > 0 && (
              <div className="space-y-2">
                <label className="text-xs text-muted-foreground uppercase tracking-[0.02em] font-medium">
                  Reference Page
                </label>
                <select
                  value={referencePageNumber}
                  onChange={(e) =>
                    setReferencePageNumber(Number(e.target.value))
                  }
                  className="w-full bg-background/80 border border-border/50 rounded-md px-3 py-2 text-sm text-white focus:outline-none focus:ring-2 focus:ring-indigo/50"
                >
                  {allPages.map((page) => (
                    <option key={page.pageNumber} value={page.pageNumber}>
                      Page {page.pageNumber}
                    </option>
                  ))}
                </select>
              </div>
            )}

            <div className="relative glass-panel p-1 rounded-xl group focus-within:border-indigo/30 transition-colors">
              <div className="bg-background/80 rounded-lg p-4 border border-border/50">
                <div className="flex justify-between items-center mb-3">
                  <label className="text-[10px] uppercase text-muted-foreground tracking-[0.02em] font-medium">
                    Prompt
                  </label>
                  <div className="flex items-center gap-2 text-[10px] text-muted-foreground">
                    <span className="capitalize">{selectedStyleName}</span>
                  </div>
                </div>

                <textarea
                  value={prompt}
                  onChange={(e) => setPrompt(e.target.value)}
                  placeholder="Continue the story... Describe what happens next in your comic."
                  className="w-full bg-transparent border-none text-sm text-white placeholder-muted-foreground/50 focus:ring-0 focus:outline-none resize-none h-20 leading-relaxed tracking-tight"
                />

                <div className="mt-3 pt-3 border-t border-border/30 space-y-3">
                  {/* Existing Characters */}
                  {referencePage &&
                    referencePage.characterImages.length > 0 && (
                      <div className="space-y-2">
                        <div className="text-xs text-muted-foreground uppercase tracking-[0.02em] font-medium">
                          Reuse Characters
                        </div>
                        <div className="flex items-center gap-2 flex-wrap">
                          {referencePage.characterImages.map((characterUrl) => {
                            const isSelected =
                              selectedExistingCharacters.includes(characterUrl);
                            return (
                              <button
                                key={characterUrl}
                                onClick={() =>
                                  toggleExistingCharacter(characterUrl)
                                }
                                className={`relative w-8 h-8 rounded-md overflow-hidden border-2 transition-all ${
                                  isSelected
                                    ? "border-indigo shadow-sm shadow-indigo/20"
                                    : "border-border/50 hover:border-indigo/50"
                                }`}
                              >
                                <img
                                  src={characterUrl}
                                  alt="Existing character"
                                  className="w-full h-full object-cover"
                                />
                                {isSelected && (
                                  <div className="absolute inset-0 bg-indigo/20 flex items-center justify-center">
                                    <div className="w-3 h-3 bg-indigo rounded-full flex items-center justify-center">
                                      <div className="w-1 h-1 bg-white rounded-full" />
                                    </div>
                                  </div>
                                )}
                              </button>
                            );
                          })}
                        </div>
                      </div>
                    )}

                  {/* New Character Uploads */}
                  <div className="flex items-center justify-between gap-2">
                    <div className="flex items-center gap-2 flex-1 min-w-0">
                      {uploadedFiles.length > 0 ? (
                        <div className="flex items-center gap-2">
                          {previews.map((preview, index) => (
                            <div key={index} className="relative group/thumb">
                              <button
                                onClick={() => setShowPreview(index)}
                                className="w-8 h-8 rounded-md overflow-hidden border border-border/50 hover:border-indigo/50 transition-colors"
                              >
                                <img
                                  src={preview || "/placeholder.svg"}
                                  alt={`New character ${index + 1}`}
                                  className="w-full h-full object-cover"
                                />
                              </button>
                              <button
                                onClick={(e) => {
                                  e.stopPropagation();
                                  removeFile(index);
                                }}
                                className="absolute -top-1.5 -right-1.5 w-4 h-4 bg-red-500 hover:bg-red-600 rounded-full flex items-center justify-center opacity-0 group-hover/thumb:opacity-100 transition-opacity"
                              >
                                <X className="w-2.5 h-2.5 text-white" />
                              </button>
                            </div>
                          ))}
                          {uploadedFiles.length < 2 && (
                            <button
                              onClick={() => fileInputRef.current?.click()}
                              className="w-8 h-8 rounded-md border border-dashed border-border/50 hover:border-indigo/50 flex items-center justify-center text-muted-foreground hover:text-white transition-colors"
                            >
                              <Upload className="w-3.5 h-3.5" />
                            </button>
                          )}
                        </div>
                      ) : (
                        <button
                          onClick={() => fileInputRef.current?.click()}
                          className="flex items-center gap-2 text-xs text-muted-foreground hover:text-white transition-colors"
                        >
                          <Upload className="w-3.5 h-3.5" />
                          <span>Upload New Characters</span>
                          <span className="text-muted-foreground/50">
                            (Max 2)
                          </span>
                        </button>
                      )}
                    </div>
                  </div>
                </div>

                <input
                  ref={fileInputRef}
                  type="file"
                  accept="image/png,image/jpeg,image/jpg"
                  multiple
                  className="hidden"
                  onChange={(e) => handleFiles(e.target.files)}
                />
              </div>
            </div>

            <Button
              onClick={handleGenerate}
              disabled={!prompt.trim() || isGenerating}
              className="w-full gap-2 bg-white hover:bg-neutral-200 text-black tracking-tight"
            >
              {isGenerating ? (
                <>
                  <Loader2 className="w-4 h-4 animate-spin" />
                  <span>Generating...</span>
                </>
              ) : (
                `Generate Page ${pageNumber}`
              )}
            </Button>
          </div>
        </DialogContent>
      </Dialog>

      {showPreview !== null && previews[showPreview] && (
        <div
          className="fixed inset-0 bg-black/80 backdrop-blur-sm z-[100] flex items-center justify-center p-4"
          onClick={() => setShowPreview(null)}
        >
          <div className="relative max-w-2xl max-h-[80vh] glass-panel p-4 rounded-xl z-[101]">
            <Button
              variant="ghost"
              size="icon"
              className="absolute top-2 right-2 h-8 w-8 hover:bg-white/10 z-[102]"
              onClick={() => setShowPreview(null)}
            >
              <X className="w-4 h-4" />
            </Button>
            <img
              src={previews[showPreview] || "/placeholder.svg"}
              alt="Character preview"
              className="w-full h-full object-contain rounded-lg"
            />
          </div>
        </div>
      )}
    </>
  );
}