import { useState } from 'react'
import { FlaskConical, Loader2 } from 'lucide-react'
import type { BacktestResult } from '../../lib/api'
import { runBacktest } from '../../lib/api'

interface Props {
  onResult: (result: BacktestResult) => void
}

const INSTRUMENTS = [
  'EUR_USD', 'GBP_USD', 'USD_JPY', 'USD_CHF', 'AUD_USD', 'USD_CAD',
  'GBP_JPY', 'EUR_JPY', 'SPX500_USD', 'NAS100_USD', 'XAU_USD',
]

const GRANULARITIES = ['M1', 'M5', 'M15', 'M30', 'H1', 'H4', 'D']

const HTF_MAP: Record<string, string> = {
  M1: 'M5', M5: 'M15', M15: 'H1', M30: 'H1', H1: 'H4', H4: 'D', D: 'D',
}

export default function BacktestForm({ onResult }: Props) {
  const [loading, setLoading] = useState(false)
  const [error, setError] = useState<string | null>(null)

  const [form, setForm] = useState({
    instrument: 'EUR_USD',
    granularity: 'H1',
    candle_count: 500,
    initial_balance: 10000,
    risk_percent: 1.0,
    rr_ratio: 2.0,
    swing_strength: 5,
    liquidity_tolerance_pips: 2.0,
    spread_pips: 1.5,
  })

  const [strategies, setStrategies] = useState<string[]>(['order_block_sweep'])
  const [filters, setFilters] = useState<string[]>([])
  const [htfEmaFast, setHtfEmaFast] = useState(20)
  const [htfEmaSlow, setHtfEmaSlow] = useState(50)

  const handleChange = (key: string, value: string | number) => {
    setForm((prev) => ({ ...prev, [key]: value }))
  }

  const toggleStrategy = (name: string) => {
    setStrategies((prev) =>
      prev.includes(name) ? prev.filter((s) => s !== name) : [...prev, name]
    )
  }

  const toggleFilter = (name: string) => {
    setFilters((prev) =>
      prev.includes(name) ? prev.filter((f) => f !== name) : [...prev, name]
    )
  }

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault()
    setLoading(true)
    setError(null)
    try {
      const result = await runBacktest({
        ...form,
        strategies,
        filters,
        ...(filters.includes('htf_trend_filter') ? { htf_ema_fast: htfEmaFast, htf_ema_slow: htfEmaSlow } : {}),
      })
      onResult(result)
    } catch (err: unknown) {
      const msg = err instanceof Error ? err.message : 'Erreur inconnue'
      setError(msg)
    } finally {
      setLoading(false)
    }
  }

  const Field = ({
    label, name, type = 'number', options, value, onChange,
  }: {
    label: string; name: string; type?: string; options?: string[]
    value?: number; onChange?: (v: number) => void
  }) => (
    <div>
      <label className="block text-xs text-[#64748b] mb-1">{label}</label>
      {options ? (
        <select
          value={form[name as keyof typeof form]}
          onChange={(e) => handleChange(name, e.target.value)}
          className="w-full bg-[#0f1117] border border-[#2a2d3e] rounded-lg px-3 py-2 text-sm text-white focus:outline-none focus:border-[#6366f1]"
        >
          {options.map((o) => <option key={o} value={o}>{o}</option>)}
        </select>
      ) : (
        <input
          type={type}
          step="any"
          value={value ?? form[name as keyof typeof form]}
          onChange={(e) => {
            const v = parseFloat(e.target.value) || 0
            if (onChange) onChange(v)
            else handleChange(name, v)
          }}
          className="w-full bg-[#0f1117] border border-[#2a2d3e] rounded-lg px-3 py-2 text-sm text-white focus:outline-none focus:border-[#6366f1]"
        />
      )}
    </div>
  )

  const Checkbox = ({
    label, checked, onChange, description,
  }: {
    label: string; checked: boolean; onChange: () => void; description?: string
  }) => (
    <label className="flex items-start gap-2 cursor-pointer group">
      <input
        type="checkbox"
        checked={checked}
        onChange={onChange}
        className="mt-0.5 accent-[#6366f1] w-3.5 h-3.5"
      />
      <div>
        <span className="text-sm text-white group-hover:text-[#6366f1] transition-colors">{label}</span>
        {description && <p className="text-[10px] text-[#64748b] mt-0.5">{description}</p>}
      </div>
    </label>
  )

  return (
    <form onSubmit={handleSubmit} className="bg-[#1a1d27] border border-[#2a2d3e] rounded-xl p-5 space-y-4">
      <h2 className="text-sm font-semibold text-[#64748b] uppercase tracking-wider mb-4">
        Parametres du backtest
      </h2>

      <div className="grid grid-cols-2 gap-3">
        <Field label="Instrument" name="instrument" options={INSTRUMENTS} />
        <Field label="Timeframe" name="granularity" options={GRANULARITIES} />
        <Field label="Nombre de bougies" name="candle_count" />
        <Field label="Capital initial ($)" name="initial_balance" />
        <Field label="Risque par trade (%)" name="risk_percent" />
        <Field label="Ratio R:R" name="rr_ratio" />
        <Field label="Swing strength" name="swing_strength" />
        <Field label="Tolerance liquidite (pips)" name="liquidity_tolerance_pips" />
        <Field label="Spread (pips)" name="spread_pips" />
      </div>

      {/* Limite données info */}
      {(form.granularity === 'M1' || form.granularity === 'M5') && (
        <div className="text-[10px] text-[#64748b] bg-[#0f1117] rounded-lg px-3 py-2 border border-[#2a2d3e]">
          {form.granularity === 'M1' ? 'M1 : donnees limitees a 7 jours' : 'M5 : donnees limitees a 60 jours'}
        </div>
      )}

      {/* Stratégies */}
      <div className="border-t border-[#2a2d3e] pt-3">
        <h3 className="text-[10px] text-[#64748b] uppercase tracking-wider mb-2">Strategies</h3>
        <Checkbox
          label="Order Block + Liquidity Sweep"
          description="ICT : Equal H/L, sweep et entree sur OB"
          checked={strategies.includes('order_block_sweep')}
          onChange={() => toggleStrategy('order_block_sweep')}
        />
      </div>

      {/* Filtres */}
      <div className="border-t border-[#2a2d3e] pt-3">
        <h3 className="text-[10px] text-[#64748b] uppercase tracking-wider mb-2">Filtres</h3>
        <Checkbox
          label="Filtre tendance HTF"
          description={`Trades uniquement dans le sens de la tendance ${HTF_MAP[form.granularity] ?? ''} (EMA cross)`}
          checked={filters.includes('htf_trend_filter')}
          onChange={() => toggleFilter('htf_trend_filter')}
        />
        {filters.includes('htf_trend_filter') && (
          <div className="grid grid-cols-2 gap-3 mt-2 ml-5">
            <Field
              label="EMA rapide"
              name="htf_ema_fast"
              value={htfEmaFast}
              onChange={setHtfEmaFast}
            />
            <Field
              label="EMA lente"
              name="htf_ema_slow"
              value={htfEmaSlow}
              onChange={setHtfEmaSlow}
            />
          </div>
        )}
      </div>

      {error && (
        <div className="text-sm text-[#ef5350] bg-[#ef535020] border border-[#ef535033] rounded-lg px-3 py-2">
          {error}
        </div>
      )}

      <button
        type="submit"
        disabled={loading || strategies.length === 0}
        className="w-full flex items-center justify-center gap-2 py-2.5 bg-[#6366f1] hover:bg-[#4f46e5] text-white text-sm font-medium rounded-lg transition-colors disabled:opacity-60"
      >
        {loading ? (
          <><Loader2 size={16} className="animate-spin" /> Backtesting...</>
        ) : (
          <><FlaskConical size={16} /> Lancer le backtest</>
        )}
      </button>
    </form>
  )
}