import { NextRequest, NextResponse } from 'next/server'
import { prisma } from '@/lib/prisma'
import { auth } from '@/auth'
import PptxGenJS from 'pptxgenjs'

// ─── Color helpers ─────────────────────────────────────────────────────────
const hex = (c: string) => c.replace('#', '').toUpperCase()

interface PptxPalette {
  primary: string; secondary: string; accent: string
  bg: string; text: string; muted: string; isDark: boolean
}

function resolvePalette(theme?: string): PptxPalette {
  const palettes: Record<string, PptxPalette> = {
    'midnight-cathedral': { primary: '0A0F1E', secondary: 'C9A84C', accent: 'E8D5B5', bg: '0A0F1E', text: 'F1F5F9', muted: '94A3B8', isDark: true },
    'aurora-borealis': { primary: '0F0A2A', secondary: '7C3AED', accent: '06B6D4', bg: '0F0A2A', text: 'F1F5F9', muted: '94A3B8', isDark: true },
    'tokyo-neon': { primary: '0A0A0F', secondary: 'FF006E', accent: '3A86FF', bg: '0A0A0F', text: 'F1F5F9', muted: '94A3B8', isDark: true },
    'venture-pitch': { primary: '18181B', secondary: 'F97316', accent: '14B8A6', bg: '18181B', text: 'F1F5F9', muted: '94A3B8', isDark: true },
    'forest-floor': { primary: '0D1B0E', secondary: '22C55E', accent: 'A3B18A', bg: '0D1B0E', text: 'F1F5F9', muted: '94A3B8', isDark: true },
    'steel-glass': { primary: '292524', secondary: 'D4C5A9', accent: '94A3B8', bg: '292524', text: 'F1F5F9', muted: '94A3B8', isDark: true },
    'cyberpunk-terminal': { primary: '0A0A0A', secondary: '00FF41', accent: 'FFA500', bg: '0A0A0A', text: 'F1F5F9', muted: '94A3B8', isDark: true },
    'sunlit-gallery': { primary: 'FAF7F0', secondary: 'D4A574', accent: '5B9BD5', bg: 'FAF7F0', text: '1C1C1C', muted: '64748B', isDark: false },
    'clinical-precision': { primary: 'F8FAFC', secondary: '0891B2', accent: '34D399', bg: 'F8FAFC', text: '0F172A', muted: '64748B', isDark: false },
    'editorial-ink': { primary: 'FFFCF5', secondary: '1A1A2E', accent: '800020', bg: 'FFFCF5', text: '1A1A2E', muted: '64748B', isDark: false },
    'coastal-morning': { primary: 'F0F7FF', secondary: '2563EB', accent: 'F97066', bg: 'F0F7FF', text: '0F172A', muted: '64748B', isDark: false },
    'paper-studio': { primary: 'FEFCF8', secondary: '1E293B', accent: 'C2410C', bg: 'FEFCF8', text: '1E293B', muted: '64748B', isDark: false },
    'architectural-saas': { primary: 'F2F0E9', secondary: 'A47148', accent: '4A4E69', bg: 'F2F0E9', text: '1C1C1C', muted: '64748B', isDark: false },
  }
  const key = (theme || 'architectural-saas').toLowerCase().replace(/[^a-z]/g, '-').replace(/-+/g, '-')
  return palettes[key] ?? palettes['architectural-saas']
}

// ─── PPTX Builder (new JSON format) ────────────────────────────────────────
async function buildPptx(spec: any): Promise<Buffer> {
  const pptx = new PptxGenJS()
  pptx.layout = 'LAYOUT_WIDE'
  pptx.title = spec.title || 'Presentation'
  pptx.subject = spec.title || 'Presentation'

  const p = resolvePalette(spec.theme)
  const W = 13.33, H = 7.5

  for (const slide of (spec.slides ?? [])) {
    const s = pptx.addSlide()
    // PLG watermark — bottom-right corner of LAYOUT_WIDE (13.33"×7.5")
    s.addText('memento-note.com', {
      x: 10.0, y: 7.1, w: 3.0, h: 0.25,
      fontSize: 7, fontFace: 'Arial', color: 'B8B0A8',
      align: 'right', italic: true,
    })

    switch (slide.type) {
      case 'title': {
        s.background = { color: p.isDark ? p.primary : p.secondary }
        s.addShape(pptx.ShapeType.rect, {
          x: 0, y: 0, w: W, h: 0.08,
          fill: { color: p.accent }, line: { type: 'none' },
        })
        s.addText(slide.title || spec.title, {
          x: 1, y: 2, w: W - 2, h: 2,
          fontSize: 42, color: p.isDark ? 'FFFFFF' : 'FFFFFF', bold: true, align: 'center',
        })
        if (slide.subtitle) {
          s.addText(slide.subtitle, {
            x: 1, y: 4.3, w: W - 2, h: 1,
            fontSize: 20, color: 'FFFFFF', align: 'center', transparency: 20,
          })
        }
        s.addShape(pptx.ShapeType.rect, {
          x: 0, y: H - 0.08, w: W, h: 0.08,
          fill: { color: p.accent }, line: { type: 'none' },
        })
        break
      }

      case 'bullets': {
        s.background = { color: p.bg }
        s.addShape(pptx.ShapeType.rect, {
          x: 0, y: 0, w: 0.06, h: H,
          fill: { color: p.secondary }, line: { type: 'none' },
        })
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        s.addShape(pptx.ShapeType.rect, {
          x: 0.5, y: 1.35, w: 0.5, h: 0.06,
          fill: { color: p.accent }, line: { type: 'none' },
        })
        const items = slide.items ?? []
        // Use simpler bullet format - each item as separate text call with bullet option
        items.forEach((item: string, i: number) => {
          s.addText(item, {
            x: 0.5, y: 1.6 + i * 0.45, w: W - 1, h: 0.5,
            fontSize: 17, color: p.text,
            bullet: true,
            paraSpaceAfter: 6,
          })
        })
        break
      }

      case 'chart': {
        s.background = { color: p.bg }
        s.addShape(pptx.ShapeType.rect, {
          x: 0, y: 0, w: 0.06, h: H,
          fill: { color: p.secondary }, line: { type: 'none' },
        })
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        if (slide.subtitle) {
          s.addText(slide.subtitle, {
            x: 0.5, y: 1.2, w: W - 1, h: 0.5,
            fontSize: 12, color: p.muted,
          })
        }
        const data = slide.data ?? []
        if (data.length > 0) {
          const chartType = slide.chartType === 'line' ? pptx.ChartType.line
            : slide.chartType === 'donut' ? pptx.ChartType.doughnut
            : slide.chartType === 'radar' ? pptx.ChartType.radar
            : pptx.ChartType.bar
          const chartData = [{
            name: slide.title,
            labels: data.map((d: any) => d.label),
            values: data.map((d: any) => d.value),
          }]
          s.addChart(chartType, chartData, {
            x: 0.8, y: 1.8, w: W - 1.6, h: H - 2.5,
            showValue: true,
            showTitle: false,
            showLegend: false,
            chartColors: [p.secondary, p.accent, '10B981', 'F59E0B', 'EF4444', '6366F1'],
            valAxisHidden: slide.chartType === 'donut' || slide.chartType === 'radar',
            catAxisHidden: slide.chartType === 'donut',
          })
        }
        break
      }

      case 'stats': {
        s.background = { color: p.bg }
        s.addShape(pptx.ShapeType.rect, {
          x: 0, y: 0, w: 0.06, h: H,
          fill: { color: p.secondary }, line: { type: 'none' },
        })
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        const stats = (slide.stats ?? []).slice(0, 4)
        const statW = (W - 1 - (stats.length - 1) * 0.3) / stats.length
        stats.forEach((st: any, i: number) => {
          const x = 0.5 + i * (statW + 0.3)
          s.addShape(pptx.ShapeType.rect, {
            x, y: 2, w: statW, h: 0.06,
            fill: { color: p.accent }, line: { type: 'none' },
          })
          s.addText(st.value, {
            x, y: 2.3, w: statW, h: 2,
            fontSize: 48, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true, align: 'center',
          })
          s.addText(st.label, {
            x, y: 4.4, w: statW, h: 0.7,
            fontSize: 13, color: p.muted, align: 'center',
          })
        })
        break
      }

      case 'table': {
        s.background = { color: p.bg }
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        const headers = slide.headers ?? []
        const rows = slide.rows ?? []
        if (headers.length > 0) {
          const tableRows = [
            headers.map((h: string) => ({ text: h, options: { bold: true, color: 'FFFFFF', fill: { color: p.secondary } } })),
            ...rows.map((row: string[], ri: number) =>
              row.map((cell: string) => ({ text: cell, options: { fill: { color: ri % 2 === 0 ? 'F8F8F8' : 'FFFFFF' } } }))
            ),
          ]
          s.addTable(tableRows, {
            x: 0.5, y: 1.5, w: W - 1, h: H - 2,
            fontSize: 13, color: p.text,
            border: { type: 'solid', pt: 0.5, color: 'DDDDDD' },
            colW: Array(headers.length).fill((W - 1) / headers.length),
          })
        }
        break
      }

      case 'cards': {
        s.background = { color: p.bg }
        s.addShape(pptx.ShapeType.rect, {
          x: 0, y: 0, w: 0.06, h: H,
          fill: { color: p.secondary }, line: { type: 'none' },
        })
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 26, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        const cards = (slide.cards ?? []).slice(0, 6)
        const cols = cards.length <= 2 ? 2 : cards.length <= 3 ? 3 : cards.length === 4 ? 2 : 3
        const cardW = (W - 1 - (cols - 1) * 0.2) / cols
        const cardH = cards.length > cols ? 2.3 : 3.5
        cards.forEach((card: any, i: number) => {
          const col = i % cols
          const row = Math.floor(i / cols)
          const x = 0.5 + col * (cardW + 0.2)
          const y = 1.5 + row * (cardH + 0.15)
          s.addShape(pptx.ShapeType.roundRect, {
            x, y, w: cardW, h: cardH,
            fill: { color: p.isDark ? '1E1E2E' : 'FFFFFF' },
            line: { color: p.isDark ? '333333' : 'E5E7EB', pt: 1 },
            rectRadius: 0.08,
          })
          s.addShape(pptx.ShapeType.rect, {
            x, y, w: cardW, h: 0.05,
            fill: { color: p.accent }, line: { type: 'none' },
          })
          s.addText(card.title, {
            x: x + 0.15, y: y + 0.25, w: cardW - 0.3, h: 0.6,
            fontSize: 14, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
          })
          s.addText(card.description, {
            x: x + 0.15, y: y + 0.8, w: cardW - 0.3, h: cardH - 1,
            fontSize: 12, color: p.text,
          })
        })
        break
      }

      case 'timeline': {
        s.background = { color: p.bg }
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        const events = (slide.events ?? []).slice(0, 6)
        const evH = Math.min(0.9, (H - 2) / events.length)
        events.forEach((ev: any, i: number) => {
          const y = 1.6 + i * evH
          // Dot
          s.addShape(pptx.ShapeType.ellipse, {
            x: 0.7, y: y + 0.1, w: 0.2, h: 0.2,
            fill: { color: p.accent }, line: { type: 'none' },
          })
          // Line
          if (i < events.length - 1) {
            s.addShape(pptx.ShapeType.rect, {
              x: 0.78, y: y + 0.32, w: 0.04, h: evH - 0.2,
              fill: { color: p.accent }, line: { type: 'none' },
            })
          }
          s.addText(ev.date, {
            x: 1.1, y, w: 2, h: 0.4,
            fontSize: 10, color: p.accent, bold: true,
          })
          s.addText(ev.title, {
            x: 1.1, y: y + 0.3, w: W - 2, h: 0.4,
            fontSize: 14, color: p.text, bold: true,
          })
          if (ev.description) {
            s.addText(ev.description, {
              x: 1.1, y: y + 0.6, w: W - 2, h: 0.3,
              fontSize: 11, color: p.muted,
            })
          }
        })
        break
      }

      case 'quote': {
        const qBg = p.isDark ? '0D1117' : '1A1A2E'
        s.background = { color: qBg }
        s.addText('\u201C', {
          x: 0.5, y: 0.2, w: 2, h: 2,
          fontSize: 96, color: p.accent, bold: true, transparency: 60,
        })
        s.addText(slide.quote, {
          x: 1, y: 1.5, w: W - 2, h: 3.5,
          fontSize: 24, color: 'FFFFFF', italic: true, align: 'left',
        })
        if (slide.author) {
          s.addText(`\u2014 ${slide.author}`, {
            x: 1, y: 5.2, w: W - 2, h: 0.8,
            fontSize: 14, color: p.accent, align: 'left',
          })
        }
        if (slide.context) {
          s.addText(slide.context, {
            x: 1, y: 6, w: W - 2, h: 0.8,
            fontSize: 12, color: 'AAAAAA',
          })
        }
        break
      }

      case 'comparison': {
        s.background = { color: p.bg }
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        const colW = (W - 1.5) / 2
        const colY = 1.5, colH = H - 2
        // Left
        if (slide.left) {
          s.addShape(pptx.ShapeType.roundRect, {
            x: 0.5, y: colY, w: colW, h: colH,
            fill: { color: p.isDark ? '1E1E2E' : 'F8FAFC' },
            line: { color: p.secondary, pt: 1 },
            rectRadius: 0.08,
          })
          s.addText(slide.left.title, {
            x: 0.7, y: colY + 0.15, w: colW - 0.4, h: 0.5,
            fontSize: 14, color: p.secondary, bold: true,
          })
          const lBullets = (slide.left.points ?? []).map((pt: string) => ({
            text: pt, options: { bullet: { type: 'bullet' as const }, paraSpaceAfter: 4 },
          }))
          s.addText(lBullets, {
            x: 0.7, y: colY + 0.7, w: colW - 0.4, h: colH - 1.4,
            fontSize: 13, color: p.text,
          })
          if (slide.left.score) {
            s.addText(slide.left.score, {
              x: 0.7, y: colY + colH - 0.6, w: colW - 0.4, h: 0.5,
              fontSize: 18, color: p.secondary, bold: true, align: 'center',
            })
          }
        }
        // Right
        if (slide.right) {
          const rx = 0.5 + colW + 0.5
          s.addShape(pptx.ShapeType.roundRect, {
            x: rx, y: colY, w: colW, h: colH,
            fill: { color: p.isDark ? '1E1E2E' : 'F8FAFC' },
            line: { color: p.accent, pt: 1 },
            rectRadius: 0.08,
          })
          s.addText(slide.right.title, {
            x: rx + 0.2, y: colY + 0.15, w: colW - 0.4, h: 0.5,
            fontSize: 14, color: p.accent, bold: true,
          })
          const rBullets = (slide.right.points ?? []).map((pt: string) => ({
            text: pt, options: { bullet: { type: 'bullet' as const }, paraSpaceAfter: 4 },
          }))
          s.addText(rBullets, {
            x: rx + 0.2, y: colY + 0.7, w: colW - 0.4, h: colH - 1.4,
            fontSize: 13, color: p.text,
          })
          if (slide.right.score) {
            s.addText(slide.right.score, {
              x: rx + 0.2, y: colY + colH - 0.6, w: colW - 0.4, h: 0.5,
              fontSize: 18, color: p.accent, bold: true, align: 'center',
            })
          }
        }
        break
      }

      case 'equation': {
        s.background = { color: p.bg }
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        const eqs = (slide.equations ?? []).slice(0, 4)
        const eqH = Math.min(1.5, (H - 2.5) / eqs.length)
        eqs.forEach((eq: any, i: number) => {
          const y = 1.8 + i * eqH
          s.addText(eq.latex, {
            x: 1, y, w: W - 2, h: eqH * 0.6,
            fontSize: 28, color: p.text, align: 'center', fontFace: 'Cambria Math',
          })
          if (eq.label) {
            s.addText(eq.label, {
              x: 1, y: y + eqH * 0.6, w: W - 2, h: eqH * 0.3,
              fontSize: 11, color: p.muted, align: 'center',
            })
          }
        })
        if (slide.explanation) {
          s.addText(slide.explanation, {
            x: 1, y: H - 1.2, w: W - 2, h: 0.8,
            fontSize: 12, color: p.muted, align: 'center',
          })
        }
        break
      }

      case 'image': {
        s.background = { color: p.bg }
        s.addText(slide.title, {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        if (slide.url) {
          try {
            s.addImage({
              path: slide.url,
              x: 2, y: 1.5, w: W - 4, h: H - 2.5,
              sizing: { type: 'contain', w: W - 4, h: H - 2.5 },
            })
          } catch { /* image unavailable */ }
        }
        if (slide.caption) {
          s.addText(slide.caption, {
            x: 0.5, y: H - 0.9, w: W - 1, h: 0.7,
            fontSize: 12, color: p.muted, align: 'center',
          })
        }
        break
      }

      case 'summary': {
        s.background = { color: p.bg }
        s.addShape(pptx.ShapeType.rect, {
          x: 0, y: 0, w: 0.06, h: H,
          fill: { color: p.secondary }, line: { type: 'none' },
        })
        s.addText(slide.title || 'En résumé', {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        s.addShape(pptx.ShapeType.rect, {
          x: 0.5, y: 1.35, w: 0.5, h: 0.06,
          fill: { color: p.accent }, line: { type: 'none' },
        })
        const items = (slide.items ?? []).slice(0, 8)
        items.forEach((item: string, i: number) => {
          const y = 1.6 + i * 0.7
          s.addShape(pptx.ShapeType.rect, {
            x: 0.5, y, w: W - 1, h: 0.55,
            fill: { color: i % 2 === 0 ? (p.isDark ? '1E1E2E' : 'F5F5F5') : (p.isDark ? '151525' : 'EBEBEB') },
            line: { type: 'none' },
          })
          s.addText('\u2713', {
            x: 0.7, y, w: 0.5, h: 0.55,
            fontSize: 14, color: p.accent, bold: true, valign: 'middle',
          })
          s.addText(item, {
            x: 1.3, y, w: W - 2, h: 0.55,
            fontSize: 14, color: p.text, valign: 'middle',
          })
        })
        break
      }

      // Fallback: treat as bullets
      default: {
        s.background = { color: p.bg }
        s.addText(slide.title || '', {
          x: 0.5, y: 0.4, w: W - 1, h: 0.9,
          fontSize: 28, color: p.isDark ? 'FFFFFF' : p.secondary, bold: true,
        })
        const content = slide.items || slide.content || []
        if (Array.isArray(content) && content.length) {
          const defBullets = content.map((item: string) => ({
            text: String(item),
            options: { bullet: { type: 'bullet' as const }, paraSpaceAfter: 6 },
          }))
          s.addText(defBullets, {
            x: 0.5, y: 1.5, w: W - 1, h: H - 2,
            fontSize: 17, color: p.text,
          })
        }
      }
    }
  }

  return pptx.write({ outputType: 'nodebuffer' }) as Promise<Buffer>
}

// ─── API Route ─────────────────────────────────────────────────────────────
export async function GET(req: NextRequest) {
  try {
    const session = await auth()
    if (!session?.user?.id) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const canvasId = req.nextUrl.searchParams.get('id')
    if (!canvasId) {
      return NextResponse.json({ error: 'Missing id' }, { status: 400 })
    }

    const canvas = await prisma.canvas.findUnique({
      where: { id: canvasId, userId: session.user.id },
    })
    if (!canvas) {
      return NextResponse.json({ error: 'Not found' }, { status: 404 })
    }

    let parsed: any
    try {
      parsed = JSON.parse(canvas.data)
    } catch {
      return NextResponse.json({ error: 'Invalid canvas data' }, { status: 500 })
    }

    if (parsed.type !== 'slides') {
      return NextResponse.json({ error: 'Not a slides canvas' }, { status: 400 })
    }

    // Support both new format (spec embedded) and legacy (spec at root)
    const spec = parsed.spec || parsed
    if (!spec || !Array.isArray(spec.slides)) {
      return NextResponse.json({ error: 'No slide data found — please regenerate the presentation' }, { status: 400 })
    }

    const buffer = await buildPptx(spec)
    const filename = `${(canvas.name || 'presentation').replace(/[^a-zA-Z0-9-_ ]/g, '_').trim()}.pptx`

    return new NextResponse(new Uint8Array(buffer), {
      headers: {
        'Content-Type': 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
        'Content-Disposition': `attachment; filename="${filename}"`,
        'Content-Length': String(buffer.length),
      },
    })
  } catch (err: any) {
    console.error('[PPTX Export]', err)
    return NextResponse.json({ error: err.message || 'Export failed' }, { status: 500 })
  }
}