import React, { useState } from "react"
import {
  PiFinnTheHumanLight,
  PiFinnTheHumanBold,
  PiFinnTheHumanFill,
  PiFinnTheHumanDuotone,
} from "react-icons/pi"
import { Play } from "lucide-react"
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select"
import { Button } from "@/components/ui/button"
import { Tabs, TabsList, TabsTrigger, TabsContent } from "@/components/ui/tabs"

import { Footer } from "@/components/footer"
import { Header } from "@/components/header"

// ----------------------------------------------------
// Category + Prompt Mapping
// ----------------------------------------------------
const categories = [
  { value: "lgbtq+", label: "LGBT+", prompt: "The gay people are" },
  { value: "nationality", label: "Nationality", prompt: "The French people are" },
  { value: "race", label: "Race", prompt: "The Black people are" },
]

// ----------------------------------------------------
// Minimal card
// ----------------------------------------------------
function ModelCard({
  Icon,
  title,
  text,
  streaming,
}: {
  Icon: React.ElementType
  title: string
  text: string
  streaming?: boolean
}) {
  return (
    <div className="border border-gray-200 dark:border-gray-700 rounded-lg p-6 flex flex-col min-h-[120px]">
      <div className="flex items-center gap-2 mb-2">
        <Icon className="h-5 w-5" />
        <h3 className="font-semibold">{title}</h3>
      </div>
      {/* If streaming == true, we append "●" at the end to mimic a typing indicator */}
      <div className="min-h-40 w-80 text-left">
        <p className="text-gray-700 dark:text-gray-300 whitespace-pre-wrap break-words">
          {text}
          {streaming && "●"}
          {/* // ⏺ or ⬤ or ● */}
        </p>
      </div>
    </div>
  )
}

// ----------------------------------------------------
// Tab Panel that holds 4 model cards + "Play" button
// ----------------------------------------------------
function TabPanel({
  datasetKey,
  modelKey,
  categoryKey,
  prompt,
}: {
  datasetKey: string
  modelKey: string
  categoryKey: string
  prompt: string
}) {
  // These are the four generation “modes” in sequence
  const modelSequence = [
    { type: "original", title: "Original Model", key: "origin", icon: PiFinnTheHumanLight },
    { type: "origin+steer", title: "Bias Amplified Steering", key: "origin+steer", icon: PiFinnTheHumanBold },
    { type: "trained", title: "Bias Trained Model", key: "trained", icon: PiFinnTheHumanFill },
    { type: "trained-steer", title: "Bias Mitigated Steering", key: "trained-steer", icon: PiFinnTheHumanDuotone },
  ]

  // Holds the partial or final text for each of the 4 slots
  const [outputs, setOutputs] = useState(["", "", "", ""])
  // Which slot is currently streaming? -1 if none
  const [activeIndex, setActiveIndex] = useState(-1)

  // Helper to fetch in streaming chunks
  async function fetchInChunks(genType: string, index: number) {
    const payload = {
      model: modelKey,
      dataset: datasetKey,
      category: categoryKey,
      type: genType,
    }

    const apiBaseUrl = import.meta.env.VITE_API_BASE_URL || ""
    const response = await fetch(`${apiBaseUrl}/api/generate`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    })

    // Stream the response
    const reader = response.body?.getReader()
    if (!reader) return
    const decoder = new TextDecoder("utf-8")
    let partial = ""

    while (true) {
      const { done, value } = await reader.read()
      if (done) break

      // Decode chunk and update partial text
      partial += decoder.decode(value, { stream: true })
      // Update outputs[i] in real-time
      setOutputs((prev) => {
        const copy = [...prev]
        copy[index] = partial
        return copy
      })
    }
  }

  // Called on "Play"
  async function handlePlay() {
    // Reset everything
    setOutputs(["", "", "", ""])
    setActiveIndex(-1)

    // Stream each model's text in sequence
    for (let i = 0; i < modelSequence.length; i++) {
      setActiveIndex(i)
      await fetchInChunks(modelSequence[i].type, i)
      setActiveIndex(-1) // or keep streaming indicator until next loop
    }
  }

  return (
    <div className="space-y-6">
      <div className="grid md:grid-cols-2 gap-6">
        {modelSequence.map((seq, i) => {
          const Icon = seq.icon
          return (
            <ModelCard
              key={seq.type}
              Icon={Icon}
              title={seq.title}
              text={prompt + outputs[i] || ""}
              streaming={i === activeIndex}
            />
          )
        })}
      </div>

      <div className="flex justify-center">
        <Button
          size="lg"
          className="bg-blue-500 hover:bg-blue-600 text-white px-8 rounded-full"
          onClick={handlePlay}
        >
          <Play className="w-5 h-5 mr-2" />
          Play
        </Button>
      </div>
    </div>
  )
}

// ----------------------------------------------------
// Main App
// ----------------------------------------------------
export default function App() {
  const [dataset, setDataset] = useState("Bias (EMGSD)")
  const [model, setModel] = useState("GPT-2")
  const [category, setCategory] = useState(categories[0].value)

  // Convert front-end selection to server keys
  const datasetKey = dataset === "Bias (EMGSD)" ? "emgsd" : "emgsd"
  const modelKey = model === "GPT-2" ? "gpt2" : "gpt2"

  return (
    <div className="min-h-screen flex flex-col dark:bg-transparent">
      <Header />
      {/* Main content */}
      <main className="flex-grow flex flex-col items-center justify-center">
        <div className="text-center space-y-8">
          <div className="space-y-4">
            <h1 className="text-7xl font-mono tracking-tighter text-black dark:text-white">
              CorrSteer
            </h1>
            <p className="text-xl leading-relaxed text-gray-700 dark:text-gray-300 italic px-6">
              Text Classification dataset can be used to <span className="font-bold">Steer</span> LLMs,
              <br />
              <span className="font-bold">Corr</span>elating with SAE features
            </p>
          </div>

          {/* Dropdowns */}
          <div className="grid md:grid-cols-2 gap-8">
            <div className="space-y-2 px-6 mx-8">
              <label className="text-sm font-medium dark:text-gray-300">
                Dataset
              </label>
              <Select value={dataset} onValueChange={setDataset}>
                <SelectTrigger className="dark:bg-gray-800 dark:text-white">
                  <SelectValue />
                </SelectTrigger>
                <SelectContent className="dark:bg-gray-800 dark:text-white">
                  <SelectItem value="Bias (EMGSD)">Bias (EMGSD)</SelectItem>
                </SelectContent>
              </Select>
            </div>

            <div className="space-y-2 px-6 mx-8">
              <label className="text-sm font-medium dark:text-gray-300">
                Language Model
              </label>
              <Select value={model} onValueChange={setModel}>
                <SelectTrigger className="dark:bg-gray-800 dark:text-white">
                  <SelectValue />
                </SelectTrigger>
                <SelectContent className="dark:bg-gray-800 dark:text-white">
                  <SelectItem value="GPT-2">GPT-2</SelectItem>
                </SelectContent>
              </Select>
            </div>
          </div>

          {/* Tabs: 3 categories -> each has its own content */}
          <Tabs value={category} onValueChange={setCategory}>
            <TabsList className="gap-1 bg-transparent">
              {categories.map((cat) => (
                <TabsTrigger
                  key={cat.value}
                  value={cat.value}
                  className="data-[state=active]:bg-blue-400 dark:data-[state=active]:bg-blue-500 data-[state=inactive]:bg-slate-200 dark:data-[state=inactive]:bg-slate-800 data-[state=active]:border-gray-300 px-4 py-2 text-sm"
                >
                  {cat.label}
                </TabsTrigger>
              ))}
            </TabsList>

            {categories.map((cat) => (
              <TabsContent key={cat.value} value={cat.value} className="p-6">
                <TabPanel
                  datasetKey={datasetKey}
                  modelKey={modelKey}
                  categoryKey={category}
                  prompt={cat.prompt}
                />
              </TabsContent>
            ))}
          </Tabs>
        </div>
      </main>
      <Footer />
    </div>
  )
}