"use client";

import { useState, useCallback, useRef } from "react";
import { useRouter } from "next/navigation";
import Link from "next/link";
import { Button } from "@/components/ui/button";
import { Textarea } from "@/components/ui/textarea";
import { useToast } from "@/components/ui/use-toast";
import { cn } from "@/lib/utils";
import {
  ArrowLeft,
  Upload,
  AlertCircle,
  CheckCircle2,
  RefreshCw,
  SkipForward,
  FilePlus2,
  Pencil,
  Film,
} from "lucide-react";
import { parseEdlCsv } from "@/lib/edl-utils";
import type { EdlImportRow } from "@/lib/edl-utils";
import { importShotsFromEdl } from "@/actions/shots";

interface EdlImportClientProps {
  projectId: string;
  projectName: string;
  existingShotCodes: Set<string>;
}

type Step = "input" | "preview" | "result";

const ACTION_STYLES = {
  create: "bg-emerald-500/10 text-emerald-400 border-emerald-500/20",
  update: "bg-blue-500/10 text-blue-400 border-blue-500/20",
  skip:   "bg-zinc-500/10 text-zinc-400 border-zinc-500/20",
};

const ACTION_ICONS = {
  create: FilePlus2,
  update: Pencil,
  skip:   SkipForward,
};

export function EdlImportClient({ projectId, projectName, existingShotCodes }: EdlImportClientProps) {
  const router = useRouter();
  const { toast } = useToast();
  const fileInputRef = useRef<HTMLInputElement>(null);

  const [step, setStep] = useState<Step>("input");
  const [csvText, setCsvText] = useState("");
  const [rows, setRows] = useState<EdlImportRow[]>([]);
  const [parseErrors, setParseErrors] = useState<string[]>([]);
  const [importing, setImporting] = useState(false);
  const [result, setResult] = useState<{ created: string[]; updated: string[]; skipped: string[]; errors: string[] } | null>(null);

  const handleFileUpload = (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (!file) return;
    const reader = new FileReader();
    reader.onload = (ev) => setCsvText(ev.target?.result as string ?? "");
    reader.readAsText(file);
    e.target.value = "";
  };

  const handleParse = useCallback(() => {
    const { rows: parsed, errors } = parseEdlCsv(csvText);
    setParseErrors(errors);

    // Determine action for each row based on existing shots
    const withActions: EdlImportRow[] = parsed.map((row) => ({
      ...row,
      action: existingShotCodes.has(row.shotCode) ? "update" : "create",
    }));

    setRows(withActions);
    if (withActions.length > 0) setStep("preview");
  }, [csvText, existingShotCodes]);

  const toggleAction = (idx: number) => {
    setRows((prev) =>
      prev.map((r, i) => {
        if (i !== idx) return r;
        const cycle: EdlImportRow["action"][] = ["create", "update", "skip"];
        const next = cycle[(cycle.indexOf(r.action) + 1) % cycle.length];
        return { ...r, action: next };
      })
    );
  };

  const setAllAction = (action: EdlImportRow["action"]) => {
    setRows((prev) => prev.map((r) => ({ ...r, action })));
  };

  const handleImport = async () => {
    setImporting(true);
    try {
      const res = await importShotsFromEdl(projectId, rows);
      setResult(res);
      setStep("result");
      if (res.created.length + res.updated.length > 0) {
        toast({
          title: `Import complete`,
          description: `${res.created.length} created, ${res.updated.length} updated`,
        });
      }
    } catch (e) {
      toast({ title: "Import failed", description: e instanceof Error ? e.message : undefined, variant: "destructive" });
    } finally {
      setImporting(false);
    }
  };

  const handleReset = () => {
    setStep("input");
    setCsvText("");
    setRows([]);
    setParseErrors([]);
    setResult(null);
  };

  const counts = {
    create: rows.filter((r) => r.action === "create").length,
    update: rows.filter((r) => r.action === "update").length,
    skip:   rows.filter((r) => r.action === "skip").length,
  };

  return (
    <div className="min-h-screen bg-background">
      <div className="max-w-5xl mx-auto p-6 space-y-6">
        {/* Breadcrumb */}
        <div className="flex items-center gap-2 text-sm text-zinc-500">
          <Link href="/projects" className="hover:text-white transition-colors">Projects</Link>
          <span>/</span>
          <Link href={`/projects/${projectId}`} className="hover:text-white transition-colors">{projectName}</Link>
          <span>/</span>
          <span className="text-zinc-300">Import VFX Pull</span>
        </div>

        {/* Header */}
        <div className="flex items-center gap-3">
          <Button variant="ghost" size="icon" className="h-8 w-8 -ml-2" asChild>
            <Link href={`/projects/${projectId}`}><ArrowLeft className="h-4 w-4" /></Link>
          </Button>
          <div>
            <h1 className="text-xl font-bold text-white">Import VFX Pull CSV</h1>
            <p className="text-sm text-zinc-500 mt-0.5">Paste or upload a Colorfront VFX pull CSV to create or update shots</p>
          </div>
        </div>

        {/* ── STEP 1: Input ─────────────────────────────────────────────────── */}
        {step === "input" && (
          <div className="space-y-4">
            <div className="rounded-xl border border-zinc-800 bg-zinc-900 p-5 space-y-4">
              <div className="flex items-center justify-between">
                <p className="text-sm font-medium text-zinc-300">Paste CSV or upload file</p>
                <div className="flex items-center gap-2">
                  <input
                    ref={fileInputRef}
                    type="file"
                    accept=".csv,text/csv"
                    className="hidden"
                    onChange={handleFileUpload}
                  />
                  <Button
                    variant="outline"
                    size="sm"
                    className="gap-1.5 h-7"
                    onClick={() => fileInputRef.current?.click()}
                  >
                    <Upload className="h-3.5 w-3.5" />
                    Upload .csv
                  </Button>
                </div>
              </div>

              <Textarea
                value={csvText}
                onChange={(e) => setCsvText(e.target.value)}
                placeholder={`Events,"Deliverable Name","Output Name","Source Clip","Timecode Start","Timecode End",Duration,CDL,Status,Trimmed\n000001,VFX_Pull_Default_EXR,"UNG_108_001_010_BG01_TT_v001",A315C001_260313H1,...`}
                className="font-mono text-xs min-h-[280px] bg-zinc-950 border-zinc-700 resize-y"
                spellCheck={false}
              />

              <div className="rounded-lg bg-zinc-950 border border-zinc-800 p-3 text-xs text-zinc-400 space-y-1">
                <p className="font-medium text-zinc-300">Expected format</p>
                <p>Columns required: <span className="font-mono text-amber-400">Output Name</span>, <span className="font-mono text-amber-400">Source Clip</span></p>
                <p>Optional: <span className="font-mono text-zinc-400">Timecode Start, Timecode End, Duration</span></p>
                <p className="mt-1.5">Shot code is derived from the first 4 segments of Output Name, e.g. <span className="font-mono text-zinc-300">UNG_108_030_060_BG01_TT_v001</span> → <span className="font-mono text-emerald-400">UNG_108_030_060</span></p>
                <p>EXR Output = <span className="font-mono text-zinc-300">{"{shot_code}_{source_clip}"}</span></p>
              </div>
            </div>

            <div className="flex justify-end">
              <Button onClick={handleParse} disabled={!csvText.trim()} className="gap-2">
                <Film className="h-4 w-4" />
                Parse &amp; Preview
              </Button>
            </div>
          </div>
        )}

        {/* ── STEP 2: Preview ───────────────────────────────────────────────── */}
        {step === "preview" && (
          <div className="space-y-4">
            {/* Summary bar */}
            <div className="flex flex-wrap items-center gap-3">
              <div className="flex items-center gap-2 px-3 py-1.5 rounded-lg bg-emerald-500/10 border border-emerald-500/20 text-emerald-400 text-sm">
                <FilePlus2 className="h-3.5 w-3.5" />
                {counts.create} to create
              </div>
              <div className="flex items-center gap-2 px-3 py-1.5 rounded-lg bg-blue-500/10 border border-blue-500/20 text-blue-400 text-sm">
                <Pencil className="h-3.5 w-3.5" />
                {counts.update} to update
              </div>
              {counts.skip > 0 && (
                <div className="flex items-center gap-2 px-3 py-1.5 rounded-lg bg-zinc-500/10 border border-zinc-500/20 text-zinc-400 text-sm">
                  <SkipForward className="h-3.5 w-3.5" />
                  {counts.skip} to skip
                </div>
              )}
              <div className="ml-auto flex items-center gap-2">
                <span className="text-xs text-zinc-500">Set all:</span>
                <Button variant="outline" size="sm" className="h-7 text-xs gap-1" onClick={() => setAllAction("create")}>Create</Button>
                <Button variant="outline" size="sm" className="h-7 text-xs gap-1" onClick={() => setAllAction("update")}>Update</Button>
                <Button variant="outline" size="sm" className="h-7 text-xs gap-1" onClick={() => setAllAction("skip")}>Skip</Button>
              </div>
            </div>

            {parseErrors.length > 0 && (
              <div className="rounded-lg bg-red-500/10 border border-red-500/20 p-3 space-y-1">
                <p className="text-xs font-medium text-red-400 flex items-center gap-1.5">
                  <AlertCircle className="h-3.5 w-3.5" /> {parseErrors.length} parse warning{parseErrors.length !== 1 ? "s" : ""}
                </p>
                {parseErrors.map((e, i) => <p key={i} className="text-xs text-red-300 pl-5">{e}</p>)}
              </div>
            )}

            {/* Table */}
            <div className="rounded-xl border border-zinc-800 overflow-hidden">
              <div className="grid grid-cols-[auto_1fr_1fr_1fr_1fr_auto] text-xs font-medium text-zinc-500 uppercase tracking-wider bg-zinc-900 px-4 py-2.5 gap-4 border-b border-zinc-800">
                <span>Action</span>
                <span>Shot Code</span>
                <span>EXR Output</span>
                <span>TC In → Out</span>
                <span>Duration</span>
                <span>Source Clip</span>
              </div>
              <div className="divide-y divide-zinc-800/60 bg-zinc-950/40 max-h-[480px] overflow-y-auto">
                {rows.map((row, i) => {
                  const ActionIcon = ACTION_ICONS[row.action];
                  return (
                    <div
                      key={i}
                      className="grid grid-cols-[auto_1fr_1fr_1fr_1fr_auto] items-center gap-4 px-4 py-3 text-sm"
                    >
                      {/* Action badge — click to cycle */}
                      <button
                        onClick={() => toggleAction(i)}
                        title="Click to cycle: create → update → skip"
                        className={cn(
                          "inline-flex items-center gap-1.5 px-2 py-0.5 rounded border text-xs font-medium transition-colors shrink-0",
                          ACTION_STYLES[row.action]
                        )}
                      >
                        <ActionIcon className="h-3 w-3" />
                        {row.action}
                      </button>

                      <span className="font-mono text-xs text-zinc-200 truncate">{row.shotCode}</span>
                      <span className="font-mono text-xs text-zinc-400 truncate">{row.exrOutput}</span>
                      <span className="font-mono text-xs text-zinc-500 truncate">
                        {row.timecodeStart && row.timecodeEnd
                          ? `${row.timecodeStart} → ${row.timecodeEnd}`
                          : "—"}
                      </span>
                      <span className="font-mono text-xs text-zinc-500">{row.clipDuration || "—"}</span>
                      <span className="font-mono text-xs text-zinc-500 truncate">{row.sourceClip || "—"}</span>
                    </div>
                  );
                })}
              </div>
            </div>

            <div className="flex items-center justify-between">
              <Button variant="outline" onClick={handleReset}>
                <ArrowLeft className="h-4 w-4 mr-1.5" /> Back
              </Button>
              <Button
                onClick={handleImport}
                disabled={importing || (counts.create + counts.update === 0)}
                className="gap-2"
              >
                {importing ? <RefreshCw className="h-4 w-4 animate-spin" /> : <Upload className="h-4 w-4" />}
                {importing ? "Importing…" : `Import ${counts.create + counts.update} shot${counts.create + counts.update !== 1 ? "s" : ""}`}
              </Button>
            </div>
          </div>
        )}

        {/* ── STEP 3: Result ───────────────────────────────────────────────── */}
        {step === "result" && result && (
          <div className="space-y-4">
            <div className="rounded-xl border border-zinc-800 bg-zinc-900 p-6 space-y-5">
              <h2 className="text-base font-semibold text-white flex items-center gap-2">
                <CheckCircle2 className="h-5 w-5 text-emerald-400" />
                Import complete
              </h2>

              {result.created.length > 0 && (
                <div className="space-y-2">
                  <p className="text-xs font-medium text-emerald-400 uppercase tracking-wide">
                    Created ({result.created.length})
                  </p>
                  <div className="flex flex-wrap gap-1.5">
                    {result.created.map((c) => (
                      <span key={c} className="font-mono text-xs px-2 py-0.5 rounded bg-emerald-500/10 border border-emerald-500/20 text-emerald-300">{c}</span>
                    ))}
                  </div>
                </div>
              )}

              {result.updated.length > 0 && (
                <div className="space-y-2">
                  <p className="text-xs font-medium text-blue-400 uppercase tracking-wide">
                    Updated ({result.updated.length})
                  </p>
                  <div className="flex flex-wrap gap-1.5">
                    {result.updated.map((c) => (
                      <span key={c} className="font-mono text-xs px-2 py-0.5 rounded bg-blue-500/10 border border-blue-500/20 text-blue-300">{c}</span>
                    ))}
                  </div>
                </div>
              )}

              {result.skipped.length > 0 && (
                <div className="space-y-2">
                  <p className="text-xs font-medium text-zinc-500 uppercase tracking-wide">
                    Skipped ({result.skipped.length})
                  </p>
                  <div className="flex flex-wrap gap-1.5">
                    {result.skipped.map((c) => (
                      <span key={c} className="font-mono text-xs px-2 py-0.5 rounded bg-zinc-800 border border-zinc-700 text-zinc-400">{c}</span>
                    ))}
                  </div>
                </div>
              )}

              {result.errors.length > 0 && (
                <div className="space-y-2">
                  <p className="text-xs font-medium text-red-400 uppercase tracking-wide flex items-center gap-1.5">
                    <AlertCircle className="h-3.5 w-3.5" /> Errors ({result.errors.length})
                  </p>
                  {result.errors.map((e, i) => (
                    <p key={i} className="text-xs text-red-300 pl-5">{e}</p>
                  ))}
                </div>
              )}
            </div>

            <div className="flex items-center gap-3">
              <Button variant="outline" onClick={handleReset}>
                Import Another
              </Button>
              <Button onClick={() => router.push(`/projects/${projectId}`)}>
                Back to Project
              </Button>
            </div>
          </div>
        )}
      </div>
    </div>
  );
}