import UIKit
import PDFKit

enum ExportFormat: String, CaseIterable { case insurance = "PDF"; case arena = "Arena"; case mtgo = "MTGO"; case csv = "CSV" }

// MARK: - EXPORT ENGINE
class ExportEngine {
    static func generateString(cards: [SavedCard], format: ExportFormat) -> String {
        if format == .csv {
            func cleanCSV(_ text: String) -> String { return text.replacingOccurrences(of: "\"", with: "\"\"") }
            var csv = "Count,Name,Set,Number,Condition,Foil,Price,Serialized\n"
            for card in cards {
                let ser = (card.isSerialized ?? false) ? "Yes" : "No"
                let line = "1,\"\(cleanCSV(card.name))\",\(card.setCode),\(card.collectorNumber),\(card.condition),\(card.foilType),\(card.currentValuation ?? 0.0),\(ser)\n"
                csv.append(line)
            }
            return csv
        } else if format == .mtgo {
            return cards.map { "1 \($0.name)" }.joined(separator: "\n")
        } else {
            // Arena
            return cards.map { "1 \($0.name) (\($0.setCode)) \($0.collectorNumber)" }.joined(separator: "\n")
        }
    }

    static func generate(cards: [SavedCard], format: ExportFormat) -> URL? {
        if format == .insurance { return generatePDF(cards: cards) }

        let text = generateString(cards: cards, format: format)
        let filename = format == .csv ? "Collection.csv" : (format == .mtgo ? "MTGO_List.txt" : "Arena_Decklist.txt")
        let path = FileManager.default.temporaryDirectory.appendingPathComponent(filename)
        try? text.write(to: path, atomically: true, encoding: .utf8)
        return path
    }

    private static func generatePDF(cards: [SavedCard]) -> URL? {
        let fmt = UIGraphicsPDFRendererFormat()
        fmt.documentInfo = [kCGPDFContextCreator: "IYmtg"] as [String: Any]
        let url = FileManager.default.temporaryDirectory.appendingPathComponent("Insurance.pdf")

        let totalVal = cards.reduce(0) { $0 + ($1.currentValuation ?? 0) }
        let count = cards.count

        UIGraphicsPDFRenderer(bounds: CGRect(x: 0, y: 0, width: 612, height: 792), format: fmt).writePDF(to: url) { ctx in
            var pageY: CGFloat = 50
            let headerAttrs: [NSAttributedString.Key: Any] = [.font: UIFont.boldSystemFont(ofSize: 24)]
            let subHeaderAttrs: [NSAttributedString.Key: Any] = [.font: UIFont.boldSystemFont(ofSize: 14)]
            let textAttrs: [NSAttributedString.Key: Any] = [.font: UIFont.systemFont(ofSize: 12)]

            func drawHeader() {
                "Insurance Schedule - \(Date().formatted(date: .abbreviated, time: .shortened))".draw(at: CGPoint(x: 50, y: 50), withAttributes: headerAttrs)
            }

            func drawColumnHeaders(y: CGFloat) {
                let hAttrs: [NSAttributedString.Key: Any] = [.font: UIFont.boldSystemFont(ofSize: 10), .foregroundColor: UIColor.darkGray]
                "CARD DETAILS".draw(at: CGPoint(x: 100, y: y), withAttributes: hAttrs)
                "SET / #".draw(at: CGPoint(x: 310, y: y), withAttributes: hAttrs)
                "COND".draw(at: CGPoint(x: 420, y: y), withAttributes: hAttrs)
                "VALUE".draw(at: CGPoint(x: 520, y: y), withAttributes: hAttrs)
            }

            ctx.beginPage()
            drawHeader()

            // Summary Section
            "Policy Holder: __________________________".draw(at: CGPoint(x: 50, y: 90), withAttributes: subHeaderAttrs)
            "Total Items: \(count)".draw(at: CGPoint(x: 50, y: 115), withAttributes: subHeaderAttrs)
            "Total Value: \(cards.first?.currencyCode == "EUR" ? "€" : "$")\(String(format: "%.2f", totalVal))".draw(at: CGPoint(x: 200, y: 115), withAttributes: subHeaderAttrs)
            drawColumnHeaders(y: 135)

            pageY = 150

            for card in cards {
                if pageY + 65 > 740 {
                    ctx.beginPage()
                    drawHeader()
                    drawColumnHeaders(y: 75)
                    pageY = 90
                }

                // Column 0: Image
                if let img = ImageManager.load(name: card.imageFileName) {
                    img.draw(in: CGRect(x: 50, y: pageY, width: 40, height: 56))
                }

                let textY = pageY + 20
                // Column 1: Name (Truncate if long)
                let name = "\(card.name)\((card.isSerialized ?? false) ? " [S]" : "")"
                name.draw(in: CGRect(x: 100, y: textY, width: 200, height: 18), withAttributes: textAttrs)
                // Column 2: Set
                let setInfo = "\(card.setCode.uppercased()) #\(card.collectorNumber)"
                setInfo.draw(at: CGPoint(x: 310, y: textY), withAttributes: textAttrs)
                // Column 3: Condition (Short code)
                let cond = card.condition.components(separatedBy: "(").last?.replacingOccurrences(of: ")", with: "") ?? card.condition
                cond.draw(at: CGPoint(x: 420, y: textY), withAttributes: textAttrs)
                // Column 4: Value
                let val = "\(card.currencyCode == "EUR" ? "€" : "$")\(String(format: "%.2f", card.currentValuation ?? 0.0))"
                val.draw(at: CGPoint(x: 520, y: textY), withAttributes: textAttrs)

                pageY += 65
            }

            // Condensed Summary Section
            ctx.beginPage()
            drawHeader()
            "Condensed Manifest".draw(at: CGPoint(x: 50, y: 90), withAttributes: subHeaderAttrs)
            pageY = 120

            for card in cards {
                if pageY > 740 {
                    ctx.beginPage()
                    drawHeader()
                    "Condensed Manifest (Cont.)".draw(at: CGPoint(x: 50, y: 90), withAttributes: subHeaderAttrs)
                    pageY = 120
                }

                let line = "\(card.name) (\(card.setCode) #\(card.collectorNumber))"
                line.draw(in: CGRect(x: 50, y: pageY, width: 400, height: 18), withAttributes: textAttrs)

                let val = "\(card.currencyCode == "EUR" ? "€" : "$")\(String(format: "%.2f", card.currentValuation ?? 0.0))"
                val.draw(at: CGPoint(x: 500, y: pageY), withAttributes: textAttrs)
                pageY += 20
            }

            // FIX: Ensure Grand Total doesn't fall off the page
            if pageY + 40 > 792 {
                ctx.beginPage()
                drawHeader()
                pageY = 90
            }
            "GRAND TOTAL: \(cards.first?.currencyCode == "EUR" ? "€" : "$")\(String(format: "%.2f", totalVal))".draw(at: CGPoint(x: 400, y: pageY + 20), withAttributes: subHeaderAttrs)
        }
        return url
    }
}