//
//  TravelAlbumAIEditResultStore.swift
//  suixinkan
//

import CoreImage
import UIKit

/// AI 修图结果的内存数据源，在相册管理与照片预览之间共享本地演示结果。
@MainActor
final class TravelAlbumAIEditResultStore {
    /// 单张照片的修图记录。
    struct Record {
        var state: TravelAlbumAIEditResultState
        var editedImage: UIImage?
        var atmosphereImage: UIImage?
        var coverImage: UIImage?
    }

    static let shared = TravelAlbumAIEditResultStore()
    static let didChangeNotification = Notification.Name("TravelAlbumAIEditResultStore.didChange")
    static let materialIDUserInfoKey = "materialID"

    private var recordsByMaterialID: [Int: Record] = [:]

    private init() {}

    /// 获取指定照片的修图状态。
    func state(for materialID: Int) -> TravelAlbumAIEditResultState {
        recordsByMaterialID[materialID]?.state ?? TravelAlbumAIEditResultState()
    }

    /// 获取指定照片最新的修图结果。
    func editedImage(for materialID: Int) -> UIImage? {
        recordsByMaterialID[materialID]?.editedImage
    }

    /// 获取指定照片最新的氛围感修图结果。
    func atmosphereImage(for materialID: Int) -> UIImage? {
        recordsByMaterialID[materialID]?.atmosphereImage
    }

    /// 获取指定照片最新的封面模板结果。
    func coverImage(for materialID: Int) -> UIImage? {
        recordsByMaterialID[materialID]?.coverImage
    }

    /// 将照片标记为修图中，已有结果继续保留到新结果完成。
    func startProcessing(materialIDs: [Int]) {
        materialIDs.forEach { materialID in
            var record = recordsByMaterialID[materialID]
                ?? Record(
                    state: TravelAlbumAIEditResultState(),
                    editedImage: nil,
                    atmosphereImage: nil,
                    coverImage: nil
                )
            record.state.startProcessing()
            recordsByMaterialID[materialID] = record
            notifyChange(materialID: materialID)
        }
    }

    /// 保存最新结果并覆盖同一照片之前的修图结果。
    func complete(
        materialID: Int,
        presetID: String,
        atmosphereOptionID: String? = nil,
        coverTemplateID: String? = nil,
        editedImage: UIImage,
        atmosphereImage: UIImage? = nil,
        coverImage: UIImage? = nil
    ) {
        var record = recordsByMaterialID[materialID]
            ?? Record(
                state: TravelAlbumAIEditResultState(),
                editedImage: nil,
                atmosphereImage: nil,
                coverImage: nil
            )
        record.state.complete(
            presetID: presetID,
            atmosphereOptionID: atmosphereOptionID,
            coverTemplateID: coverTemplateID
        )
        record.editedImage = editedImage
        record.atmosphereImage = atmosphereImage
        record.coverImage = coverImage
        recordsByMaterialID[materialID] = record
        notifyChange(materialID: materialID)
    }

    /// 修图失败时恢复按钮可用状态，并保留之前成功的结果。
    func failProcessing(materialID: Int) {
        guard var record = recordsByMaterialID[materialID] else { return }
        record.state.failProcessing()
        recordsByMaterialID[materialID] = record
        notifyChange(materialID: materialID)
    }

    /// 还原为原图时清除该照片的本地修图结果。
    func restoreOriginal(materialID: Int) {
        guard var record = recordsByMaterialID[materialID] else { return }
        record.state.restoreOriginal()
        record.editedImage = nil
        record.atmosphereImage = nil
        record.coverImage = nil
        recordsByMaterialID[materialID] = record
        notifyChange(materialID: materialID)
    }

    /// 切换指定照片当前展示的原图或修图后版本。
    func selectDisplayMode(_ mode: TravelAlbumAIEditResultState.DisplayMode, materialID: Int) {
        guard var record = recordsByMaterialID[materialID] else { return }
        record.state.selectDisplayMode(mode)
        recordsByMaterialID[materialID] = record
        notifyChange(materialID: materialID)
    }

    /// 删除照片时同步清理其本地修图结果。
    func remove(materialID: Int) {
        recordsByMaterialID.removeValue(forKey: materialID)
        notifyChange(materialID: materialID)
    }

    private func notifyChange(materialID: Int) {
        NotificationCenter.default.post(
            name: Self.didChangeNotification,
            object: self,
            userInfo: [Self.materialIDUserInfoKey: materialID]
        )
    }
}

/// 本地 AI 修图效果生成器；后续接入服务端时可替换为结果图片下载。
@MainActor
enum TravelAlbumAIEditImageProcessor {
    private static let context = CIContext()

    /// 根据预设生成演示用修图图片。
    static func render(
        effect: TravelAlbumEditPreset.Effect,
        source: UIImage
    ) -> UIImage {
        guard effect != .original, let ciImage = CIImage(image: source) else { return source }
        let output: CIImage
        switch effect {
        case .original:
            output = ciImage
        case .portrait:
            output = ciImage.applyingFilter("CIColorControls", parameters: [
                kCIInputSaturationKey: 0.86,
                kCIInputBrightnessKey: 0.07,
                kCIInputContrastKey: 1.08,
            ])
        case .vintage:
            output = ciImage.applyingFilter("CISepiaTone", parameters: [kCIInputIntensityKey: 0.45])
        case .brocade:
            output = ciImage.applyingFilter("CIColorControls", parameters: [
                kCIInputSaturationKey: 1.22,
                kCIInputBrightnessKey: 0.04,
                kCIInputContrastKey: 1.1,
            ])
        case .distantMountain:
            output = ciImage.applyingFilter("CIColorControls", parameters: [
                kCIInputSaturationKey: 0.72,
                kCIInputBrightnessKey: 0.1,
                kCIInputContrastKey: 0.9,
            ])
        case .mist:
            output = ciImage.applyingFilter("CIColorControls", parameters: [
                kCIInputSaturationKey: 0.7,
                kCIInputBrightnessKey: 0.14,
                kCIInputContrastKey: 0.82,
            ])
        case .summer:
            output = ciImage.applyingFilter("CISepiaTone", parameters: [kCIInputIntensityKey: 0.24])
        case .rich:
            output = ciImage.applyingFilter("CIColorControls", parameters: [
                kCIInputSaturationKey: 1.38,
                kCIInputBrightnessKey: -0.02,
                kCIInputContrastKey: 1.2,
            ])
        }
        guard let cgImage = context.createCGImage(output, from: output.extent) else { return source }
        return UIImage(cgImage: cgImage, scale: source.scale, orientation: source.imageOrientation)
    }
}

/// 本地封面模板效果生成器，让封面结果在缩略图和预览页中与普通照片明显区分。
@MainActor
enum TravelAlbumCoverTemplateImageProcessor {
    /// 将照片渲染为指定封面排版；无原图时使用稳定的演示背景。
    static func render(
        template: TravelAlbumCoverTemplate,
        source: UIImage?,
        targetSize: CGSize = CGSize(width: 1200, height: 900)
    ) -> UIImage {
        UIGraphicsImageRenderer(size: targetSize).image { context in
            let bounds = CGRect(origin: .zero, size: targetSize)
            UIColor(hex: 0xCAD8E8).setFill()
            context.cgContext.fill(bounds)
            if let source {
                source.draw(in: aspectFillRect(imageSize: source.size, bounds: bounds))
            }

            let unit = min(targetSize.width / 232, targetSize.height / 208)
            switch template.previewStyle {
            case .travelMemoir:
                UIColor.black.withAlphaComponent(0.24).setFill()
                context.cgContext.fill(bounds)
                UIColor.white.setStroke()
                let oval = UIBezierPath(ovalIn: CGRect(
                    x: bounds.midX - 50 * unit,
                    y: 28 * unit,
                    width: 100 * unit,
                    height: 100 * unit
                ))
                oval.lineWidth = 9 * unit
                oval.stroke()
                drawCaption(
                    "TRAVEL\nMEMOIR",
                    in: CGRect(x: 30 * unit, y: bounds.height - 62 * unit, width: bounds.width - 60 * unit, height: 46 * unit),
                    alignment: .center,
                    fontSize: 17 * unit
                )
            case .minimal:
                UIColor.white.withAlphaComponent(0.9).setFill()
                context.cgContext.fill(CGRect(x: bounds.width * 0.55, y: 0, width: bounds.width * 0.45, height: bounds.height))
                drawCaption(
                    "LESS\nIS MORE",
                    in: CGRect(x: bounds.width * 0.62, y: bounds.midY - 27 * unit, width: bounds.width * 0.3, height: 54 * unit),
                    alignment: .left,
                    color: .black,
                    fontSize: 17 * unit
                )
            case .scenicStory:
                UIColor.black.withAlphaComponent(0.2).setFill()
                context.cgContext.fill(bounds)
                UIColor.white.setStroke()
                let inset = 20 * unit
                let frame = UIBezierPath(rect: bounds.insetBy(dx: inset, dy: inset))
                frame.lineWidth = 4 * unit
                frame.stroke()
                drawCaption(
                    "SCENIC STORY",
                    in: CGRect(x: 34 * unit, y: bounds.height - 58 * unit, width: bounds.width - 68 * unit, height: 24 * unit),
                    alignment: .center,
                    fontSize: 17 * unit
                )
            case .film:
                let stripHeight = 24 * unit
                UIColor.black.withAlphaComponent(0.72).setFill()
                context.cgContext.fill(CGRect(x: 0, y: 0, width: bounds.width, height: stripHeight))
                context.cgContext.fill(CGRect(x: 0, y: bounds.height - stripHeight, width: bounds.width, height: stripHeight))
                UIColor.white.withAlphaComponent(0.9).setFill()
                var x = 10 * unit
                while x <= bounds.width - 16 * unit {
                    context.cgContext.fill(CGRect(x: x, y: 6 * unit, width: 14 * unit, height: 10 * unit))
                    context.cgContext.fill(CGRect(
                        x: x,
                        y: bounds.height - 16 * unit,
                        width: 14 * unit,
                        height: 10 * unit
                    ))
                    x += 30 * unit
                }
                drawCaption(
                    "THE JOURNEY",
                    in: CGRect(x: 28 * unit, y: bounds.height - 60 * unit, width: bounds.width - 56 * unit, height: 24 * unit),
                    alignment: .center,
                    fontSize: 17 * unit
                )
            }
        }
    }

    private static func aspectFillRect(imageSize: CGSize, bounds: CGRect) -> CGRect {
        guard imageSize.width > 0, imageSize.height > 0 else { return bounds }
        let scale = max(bounds.width / imageSize.width, bounds.height / imageSize.height)
        let drawSize = CGSize(width: imageSize.width * scale, height: imageSize.height * scale)
        return CGRect(
            x: bounds.midX - drawSize.width / 2,
            y: bounds.midY - drawSize.height / 2,
            width: drawSize.width,
            height: drawSize.height
        )
    }

    private static func drawCaption(
        _ text: String,
        in rect: CGRect,
        alignment: NSTextAlignment,
        color: UIColor = .white,
        fontSize: CGFloat
    ) {
        let paragraph = NSMutableParagraphStyle()
        paragraph.alignment = alignment
        text.draw(
            in: rect,
            withAttributes: [
                .font: UIFont.systemFont(ofSize: fontSize, weight: .bold),
                .foregroundColor: color,
                .paragraphStyle: paragraph,
            ]
        )
    }
}