'use client'

import { useState } from 'react'
import { Badge } from '@/components/ui/badge'
import { Button } from '@/components/ui/button'
import { Card, CardContent, CardFooter, CardHeader, CardTitle } from '@/components/ui/card'
import { BUILD_PART_COST, expandCost, totalQty, upgradeCost } from '@/lib/game/ship-costs'
import type { ShipState, ShipSystemDto } from '@/lib/game/ship'
import { buildGate, effectiveCapacityCap, effectiveLevelCap } from '@/lib/game/tech'

// SHIP SYSTEMS tab — live data. The parent (MissionControl) owns the ship state so the left
// column mirrors actions immediately; this panel applies each action's response directly via
// onChanged (no polling). Buttons are disabled when unaffordable, capped or gated by an
// unresearched tech, using the same pure helpers the API enforces (lib/game/ship-costs.ts +
// lib/game/tech.ts).

interface ShipSystemsPanelProps {
  ship: ShipState | null
  narrow?: boolean
  onChanged: (next: ShipState) => void
  researchedSlugs: Set<string> // slugs of researched techs — raises caps, lifts build gates
}

export function ShipSystemsPanel({ ship, narrow, onChanged, researchedSlugs }: ShipSystemsPanelProps) {
  const [error, setError] = useState<string | null>(null)
  const [busy, setBusy] = useState(false) // one action at a time — turn-based game

  if (!ship) {
    return (
      <div style={{ border: '1px solid var(--border)', background: 'var(--surface)', padding: '0.75rem' }}>
        <span style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.12em' }}>LOADING SHIP SYSTEMS…</span>
      </div>
    )
  }

  const resources = totalQty(ship.inventory, 'resource')
  const parts = totalQty(ship.inventory, 'part')

  async function act(url: string, body: unknown) {
    setBusy(true)
    setError(null)
    try {
      const res = await fetch(url, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) })
      const data = (await res.json()) as ShipState & { error?: string }
      if (!res.ok) throw new Error(data.error ?? `HTTP ${res.status}`)
      onChanged(data) // response is the fresh ship state — apply directly
    } catch (err: unknown) {
      setError(err instanceof Error ? err.message : String(err))
    } finally {
      setBusy(false)
    }
  }

  return (
    <div style={{ display: 'flex', flexDirection: 'column', gap: '0.75rem' }}>
      {error && (
        <div style={{ border: '1px solid var(--border)', background: 'var(--surface)', padding: '0.75rem' }}>
          <span style={{ fontSize: '0.62rem', color: 'var(--color-red)', letterSpacing: '0.08em' }}>{error.toUpperCase()}</span>
        </div>
      )}
      <div style={{ display: 'grid', gridTemplateColumns: narrow ? '1fr' : 'repeat(2, 1fr)', gap: '0.75rem' }}>
        {ship.systems.map((system) => (
          <SystemCard key={system.id} system={system} resources={resources} parts={parts} busy={busy} researchedSlugs={researchedSlugs} onAct={act} />
        ))}
      </div>
    </div>
  )
}

function SystemCard({
  system,
  resources,
  parts,
  busy,
  researchedSlugs,
  onAct,
}: {
  system: ShipSystemDto
  resources: number
  parts: number
  busy: boolean
  researchedSlugs: Set<string>
  onAct: (url: string, body: unknown) => void
}) {
  const maxLevel = effectiveLevelCap(system.type, researchedSlugs)
  const maxCapacity = effectiveCapacityCap(system.type, researchedSlugs)
  const gate = buildGate(system.type, researchedSlugs) // name of the required tech, or null when ungated/researched

  const upgradeDisabled = busy || !system.built || system.level >= maxLevel || resources < upgradeCost(system.level)
  const expandDisabled = busy || !system.built || system.capacity >= maxCapacity || resources < expandCost(system.capacity)
  const buildDisabled = busy || system.built || gate !== null || parts < BUILD_PART_COST

  return (
    <Card>
      <CardHeader>
        <div style={{ display: 'flex', alignItems: 'center' }}>
          <CardTitle>{system.type}</CardTitle>
          <Badge variant={system.built ? 'ACTIVE' : 'OFFLINE'} className="ml-auto">
            {system.built ? `LV ${system.level}` : 'OFFLINE'}
          </Badge>
        </div>
      </CardHeader>
      <CardContent>
        <p style={{ fontSize: '0.65rem', color: 'var(--text-secondary)', letterSpacing: '0.08em' }}>
          {system.built ? `LEVEL ${system.level} · CAPACITY ${system.capacity}` : 'NOT INSTALLED'}
        </p>
        <p style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.08em' }}>
          {system.built
            ? `UPGRADE ${upgradeCost(system.level)}× RES · EXPAND ${expandCost(system.capacity)}× RES`
            : `BUILD ${BUILD_PART_COST}× PARTS`}
        </p>
        {!system.built && gate !== null && (
          <p style={{ fontSize: '0.62rem', color: 'var(--color-red)', letterSpacing: '0.08em' }}>REQUIRES // {gate}</p>
        )}
      </CardContent>
      <CardFooter className="gap-2">
        {system.built ? (
          <>
            <Button variant="OUTLINE" size="SM" disabled={upgradeDisabled} onClick={() => onAct('/api/ship/upgrade', { systemId: system.id })}>
              UPGRADE
            </Button>
            <Button variant="OUTLINE" size="SM" disabled={expandDisabled} onClick={() => onAct('/api/ship/expand', { systemId: system.id })}>
              EXPAND
            </Button>
          </>
        ) : (
          <Button variant="OUTLINE" size="SM" disabled={buildDisabled} onClick={() => onAct('/api/ship/build', { type: system.type })}>
            BUILD NEW
          </Button>
        )}
      </CardFooter>
    </Card>
  )
}