import jsPDF from 'jspdf'
import type { DayInfo, Person } from './types'
import { getCellStyle } from './cellColors'

const MONTH_NAMES: Record<number, string> = {
  1: 'Leden', 2: 'Únor', 3: 'Březen', 4: 'Duben', 5: 'Květen', 6: 'Červen',
  7: 'Červenec', 8: 'Srpen', 9: 'Září', 10: 'Říjen', 11: 'Listopad', 12: 'Prosinec',
}

const DAY_NAMES = ['Ne', 'Po', 'Út', 'St', 'Čt', 'Pá', 'So']

function arrayBufferToBase64(buffer: ArrayBuffer): string {
  const bytes = new Uint8Array(buffer)
  const chunks: string[] = []
  for (let i = 0; i < bytes.length; i += 8192) {
    chunks.push(String.fromCharCode.apply(null, bytes.slice(i, i + 8192) as unknown as number[]))
  }
  return btoa(chunks.join(''))
}

async function loadFont(doc: jsPDF) {
  try {
    const res = await fetch('/DejaVuSans.ttf')
    const buf = await res.arrayBuffer()
    const base64 = arrayBufferToBase64(buf)
    doc.addFileToVFS('DejaVuSans.ttf', base64)
    doc.addFont('DejaVuSans.ttf', 'DejaVu', 'normal')
    doc.setFont('DejaVu', 'normal')
    return true
  } catch (e) {
    console.error('Font load failed:', e)
    return false
  }
}

export async function exportMonthPdf(
  month: number,
  year: number,
  dayIndex: DayInfo[],
  people: Person[],
  tunnelClosures: Map<number, string>,
  tunnelColors: Map<number, string>,
) {
  const doc = new jsPDF({ orientation: 'landscape', unit: 'mm', format: 'a4' })
  const hasFont = await loadFont(doc)

  const monthDays = dayIndex.filter(d => d.month === month && d.year === year)
  if (monthDays.length === 0) return

  const firstDayIdx = dayIndex.indexOf(monthDays[0])
  const daysFromPrevMonth = Math.max(0, 34 - monthDays.length)
  const startIdx = Math.max(0, firstDayIdx - daysFromPrevMonth)
  const days = dayIndex.slice(startIdx, startIdx + 34)

  const tkbPeople = people.filter(p => p.group === 'TKB')
  const itPeople = people.filter(p => p.group === 'IT')

  // Layout: fill entire A4 landscape (297 x 210 mm)
  const pageW = 297
  const pageH = 210
  const margin = 3
  const nameColW = 50
  const daysPerPage = 17
  const cellW = (pageW - margin * 2 - nameColW) / daysPerPage

  // Row height to fill full page
  const headerH = 24
  const totalDataRows = tkbPeople.length + itPeople.length + 2
  const availableH = pageH - margin * 2 - headerH
  const rowH = availableH / totalDataRows

  // Font sizes — match day number size for readability
  const nameFontSize = 9
  const cellFontSize = 9
  const sectionFontSize = 10
  const dayNumFontSize = 10
  const dayNameFontSize = 7
  const closureFontSize = 6

  for (let pageNum = 0; pageNum < 2; pageNum++) {
    if (pageNum > 0) doc.addPage()
    const pageDays = days.slice(pageNum * daysPerPage, (pageNum + 1) * daysPerPage)
    if (pageDays.length === 0) continue

    if (hasFont) doc.setFont('DejaVu', 'normal')

    const showNames = pageNum === 0
    const gridStartX = showNames ? margin + nameColW : margin
    const gridW = pageDays.length * cellW
    const totalW = showNames ? nameColW + gridW : gridW
    const startY = margin

    // --- Header area ---

    // Month/year in top-left cell (only page 1)
    if (showNames) {
      doc.setFillColor(255, 255, 255)
      doc.rect(margin, startY, nameColW, headerH, 'F')
      doc.setFontSize(11)
      doc.setTextColor(0)
      doc.text(`${MONTH_NAMES[month]}`, margin + 2, startY + 9)
      doc.setFontSize(10)
      doc.text(`${year}`, margin + 2, startY + 17)
    }

    // Day columns header
    pageDays.forEach((d, i) => {
      const x = gridStartX + i * cellW
      const isOtherMonth = d.month !== month

      // Background
      if (isOtherMonth) {
        doc.setFillColor(235, 235, 235)
        doc.rect(x, startY, cellW, headerH, 'F')
      } else if (d.weekend) {
        doc.setFillColor(230, 230, 230)
        doc.rect(x, startY, cellW, headerH, 'F')
      }

      // Day number
      if (isOtherMonth) {
        doc.setTextColor(180, 180, 180)
      } else {
        doc.setTextColor(d.weekend ? 180 : 0, 0, 0)
      }
      doc.setFontSize(dayNumFontSize)
      doc.text(String(d.day), x + cellW / 2, startY + 7, { align: 'center' })

      // Day name
      const dow = new Date(d.year, d.month - 1, d.day).getDay()
      doc.setFontSize(dayNameFontSize)
      doc.text(DAY_NAMES[dow], x + cellW / 2, startY + 13, { align: 'center' })

      // Tunnel closure
      const closure = tunnelClosures.get(d.idx)
      const closureColor = tunnelColors.get(d.idx)
      if (closure || closureColor) {
        if (closureColor) {
          const rgb = hexToRgb(closureColor)
          doc.setFillColor(rgb.r, rgb.g, rgb.b)
        } else {
          doc.setFillColor(255, 165, 0)
        }
        if (isOtherMonth) {
          // Make closure color lighter for other months
          doc.setGState(doc.GState({ opacity: 0.4 }))
        }
        doc.rect(x, startY + 15, cellW, headerH - 15, 'F')
        if (isOtherMonth) {
          doc.setGState(doc.GState({ opacity: 1 }))
        }
        if (closure) {
          doc.setFontSize(closureFontSize)
          doc.setTextColor(isOtherMonth ? 180 : 0)
          doc.text(closure, x + cellW / 2, startY + 20, { align: 'center' })
        }
      }
    })

    // Header grid lines
    doc.setDrawColor(0, 0, 0)
    doc.setLineWidth(0.2)
    pageDays.forEach((d, i) => {
      const x = gridStartX + i * cellW
      const isOtherMonth = d.month !== month
      doc.setDrawColor(isOtherMonth ? 180 : 0, isOtherMonth ? 180 : 0, isOtherMonth ? 180 : 0)
      doc.line(x, startY, x, startY + headerH)
    })
    // Right edge of last column
    const lastDay = pageDays[pageDays.length - 1]
    const lastIsOther = lastDay && lastDay.month !== month
    doc.setDrawColor(lastIsOther ? 180 : 0, lastIsOther ? 180 : 0, lastIsOther ? 180 : 0)
    doc.line(gridStartX + pageDays.length * cellW, startY, gridStartX + pageDays.length * cellW, startY + headerH)

    doc.setDrawColor(0, 0, 0)
    doc.setLineWidth(0.3)
    doc.line(margin, startY, margin + totalW, startY)
    doc.line(margin, startY + headerH, margin + totalW, startY + headerH)
    if (showNames) doc.line(gridStartX, startY, gridStartX, startY + headerH)

    // --- Data rows ---
    let curY = startY + headerH

    // TKB section header
    doc.setFillColor(79, 70, 229)
    doc.rect(margin, curY, totalW, rowH, 'F')
    doc.setFontSize(sectionFontSize)
    doc.setTextColor(255, 255, 255)
    if (showNames) doc.text('POHOTOVOST TKB', margin + 2, curY + rowH * 0.7)
    curY += rowH

    renderPeople(doc, tkbPeople, pageDays, curY, margin, showNames ? nameColW : 0, gridStartX, cellW, rowH, showNames, nameFontSize, cellFontSize, month)
    curY += tkbPeople.length * rowH

    // IT section header
    doc.setFillColor(13, 148, 136)
    doc.rect(margin, curY, totalW, rowH, 'F')
    doc.setFontSize(sectionFontSize)
    doc.setTextColor(255, 255, 255)
    if (showNames) doc.text('POHOTOVOST IT', margin + 2, curY + rowH * 0.7)
    curY += rowH

    renderPeople(doc, itPeople, pageDays, curY, margin, showNames ? nameColW : 0, gridStartX, cellW, rowH, showNames, nameFontSize, cellFontSize, month)
    curY += itPeople.length * rowH

    // Outer border
    doc.setDrawColor(0, 0, 0)
    doc.setLineWidth(0.3)
    doc.rect(margin, startY, totalW, curY - startY)
    if (showNames) doc.line(gridStartX, startY, gridStartX, curY)
  }

  doc.save(`TKB_Plan_${MONTH_NAMES[month]}_${year}.pdf`)
}

function renderPeople(
  doc: jsPDF, people: Person[], days: DayInfo[],
  startY: number, margin: number, nameColW: number, gridStartX: number,
  cellW: number, rowH: number, showNames: boolean,
  nameFontSize: number, cellFontSize: number, activeMonth: number,
) {
  const totalW = nameColW + days.length * cellW
  const sectionH = people.length * rowH
  const textY = rowH * 0.65

  // Pass 1: Fill backgrounds
  people.forEach((person, pi) => {
    const y = startY + pi * rowH
    days.forEach((d, di) => {
      const x = gridStartX + di * cellW
      const isOtherMonth = d.month !== activeMonth
      const cellData = person.data[String(d.idx)]
      const value = cellData?.v ?? ''
      const manualColor = cellData?.color
      const style = getCellStyle(value || undefined)

      if (isOtherMonth) {
        // Light gray wash for other month cells
        doc.setFillColor(245, 245, 245)
        doc.rect(x, y, cellW, rowH, 'F')
        // If there's a value, draw it faded
        if (manualColor || style) {
          doc.setGState(doc.GState({ opacity: 0.35 }))
          const rgb = hexToRgb(manualColor ?? style!.bg)
          doc.setFillColor(rgb.r, rgb.g, rgb.b)
          doc.rect(x, y, cellW, rowH, 'F')
          doc.setGState(doc.GState({ opacity: 1 }))
        }
      } else if (manualColor) {
        const rgb = hexToRgb(manualColor)
        doc.setFillColor(rgb.r, rgb.g, rgb.b)
        doc.rect(x, y, cellW, rowH, 'F')
      } else if (style) {
        const rgb = hexToRgb(style.bg)
        doc.setFillColor(rgb.r, rgb.g, rgb.b)
        doc.rect(x, y, cellW, rowH, 'F')
      } else if (d.weekend) {
        doc.setFillColor(240, 240, 240)
        doc.rect(x, y, cellW, rowH, 'F')
      }
    })
  })

  // Pass 2: Grid lines — gray for other month columns, black for current month
  doc.setLineWidth(0.15)
  // Horizontal lines (always black)
  doc.setDrawColor(0, 0, 0)
  for (let pi = 0; pi <= people.length; pi++) {
    doc.line(margin, startY + pi * rowH, margin + totalW, startY + pi * rowH)
  }
  // Vertical lines — color depends on which month the column is in
  days.forEach((d, i) => {
    const isOtherMonth = d.month !== activeMonth
    doc.setDrawColor(isOtherMonth ? 190 : 0, isOtherMonth ? 190 : 0, isOtherMonth ? 190 : 0)
    doc.line(gridStartX + i * cellW, startY, gridStartX + i * cellW, startY + sectionH)
  })
  // Right edge
  const lastDay = days[days.length - 1]
  const lastOther = lastDay && lastDay.month !== activeMonth
  doc.setDrawColor(lastOther ? 190 : 0, lastOther ? 190 : 0, lastOther ? 190 : 0)
  doc.line(gridStartX + days.length * cellW, startY, gridStartX + days.length * cellW, startY + sectionH)

  // Name column separator
  if (showNames) {
    doc.setDrawColor(0, 0, 0)
    doc.setLineWidth(0.2)
    doc.line(gridStartX, startY, gridStartX, startY + sectionH)
  }

  // Pass 3: Text
  people.forEach((person, pi) => {
    const y = startY + pi * rowH

    if (showNames) {
      doc.setFontSize(nameFontSize)
      doc.setTextColor(0)
      const displayName = person.name + (person.note ? ` (${person.note})` : '')
      doc.text(displayName, margin + 1, y + textY, { maxWidth: nameColW - 2 })
    }

    days.forEach((d, di) => {
      const x = gridStartX + di * cellW
      const cellData = person.data[String(d.idx)]
      const value = cellData?.v ?? ''
      if (value) {
        const isOtherMonth = d.month !== activeMonth
        const manualColor = cellData?.color
        const style = getCellStyle(value || undefined)
        const textColor = manualColor
          ? (isLightColor(manualColor) ? '#333333' : '#ffffff')
          : (style?.text ?? '#333333')
        const rgb = hexToRgb(textColor)
        if (isOtherMonth) {
          doc.setTextColor(200, 200, 200)
        } else {
          doc.setTextColor(rgb.r, rgb.g, rgb.b)
        }
        doc.setFontSize(cellFontSize)
        doc.text(value, x + cellW / 2, y + textY, { align: 'center' })
      }
    })
  })
}

function hexToRgb(hex: string): { r: number; g: number; b: number } {
  let h = hex.replace('#', '')
  if (h.length === 3) h = h[0] + h[0] + h[1] + h[1] + h[2] + h[2]
  return {
    r: parseInt(h.substring(0, 2), 16) || 0,
    g: parseInt(h.substring(2, 4), 16) || 0,
    b: parseInt(h.substring(4, 6), 16) || 0,
  }
}

function isLightColor(hex: string): boolean {
  const { r, g, b } = hexToRgb(hex)
  return (r * 299 + g * 587 + b * 114) / 1000 > 128
}