import Foundation
import UIKit

public let kRDEPUBHighlightAttributeName = NSAttributedString.Key("com.RDEpubReader.highlight")

public let kRDEPUBUnderlineAttributeName = NSAttributedString.Key("com.RDEpubReader.underline")

public struct RDEPUBSelection: Codable, Equatable {

    public var bookIdentifier: String?

    public var location: RDEPUBLocation

    public var text: String

    public var rangeInfo: String?

    public var createdAt: Date

    public init(
        bookIdentifier: String? = nil,
        location: RDEPUBLocation,
        text: String,
        rangeInfo: String? = nil,
        createdAt: Date = Date()
    ) {
        self.bookIdentifier = bookIdentifier
        self.location = location
        self.text = text
        self.rangeInfo = rangeInfo?.nilIfEmpty
        self.createdAt = createdAt
    }

    public var isEmpty: Bool {
        text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
    }
}

public enum RDEPUBHighlightStyle: String, Codable {
    case highlight
    case underline
}

public enum RDEPUBAnnotationKind: String, Codable, Equatable {
    case bookmark
    case highlight
    case underline
}

public enum RDEPUBAnnotationMenuAction: Equatable {
    case copy
    case highlight
    case annotate
}

public struct RDEPUBTextOffsetRangeInfo: Codable, Equatable {

    public var kind: String

    public var href: String

    public var start: Int

    public var end: Int

    public init(href: String, start: Int, end: Int) {
        self.kind = "text-offset"
        self.href = href
        self.start = start
        self.end = end
    }

    public var nsRange: NSRange? {
        guard end > start else { return nil }
        return NSRange(location: start, length: end - start)
    }

    public func jsonString() -> String? {
        guard let data = try? JSONEncoder().encode(self) else { return nil }
        return String(data: data, encoding: .utf8)
    }

    public static func decode(from string: String?) -> RDEPUBTextOffsetRangeInfo? {
        guard let string,
              let data = string.data(using: .utf8),
              let rangeInfo = try? JSONDecoder().decode(RDEPUBTextOffsetRangeInfo.self, from: data),
              rangeInfo.kind == "text-offset",
              rangeInfo.end > rangeInfo.start else {
            return nil
        }
        return rangeInfo
    }
}

public struct RDEPUBHighlight: Codable, Equatable {

    public var id: String

    public var bookIdentifier: String?

    public var location: RDEPUBLocation

    public var text: String

    public var rangeInfo: String?

    public var style: RDEPUBHighlightStyle

    public var color: String

    public var note: String?

    public var createdAt: Date

    public init(
        id: String = UUID().uuidString,
        bookIdentifier: String? = nil,
        location: RDEPUBLocation,
        text: String,
        rangeInfo: String? = nil,
        style: RDEPUBHighlightStyle = .highlight,
        color: String = "#F8E16C",
        note: String? = nil,
        createdAt: Date = Date()
    ) {
        self.id = id
        self.bookIdentifier = bookIdentifier
        self.location = location
        self.text = text
        self.rangeInfo = rangeInfo?.nilIfEmpty
        self.style = style
        self.color = color
        self.note = note?.nilIfEmpty
        self.createdAt = createdAt
    }

    public var hasNote: Bool {
        note?.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty == false
    }

    public var uiColor: UIColor {
        UIColor(rdHexString: color, alpha: 0.35)
            ?? UIColor(red: 248 / 255, green: 225 / 255, blue: 108 / 255, alpha: 0.35)
    }

    private enum CodingKeys: String, CodingKey {
        case id
        case bookIdentifier
        case location
        case text
        case rangeInfo
        case style
        case color
        case note
        case createdAt
    }

    public init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        id = try container.decode(String.self, forKey: .id)
        bookIdentifier = try container.decodeIfPresent(String.self, forKey: .bookIdentifier)
        location = try container.decode(RDEPUBLocation.self, forKey: .location)
        text = try container.decode(String.self, forKey: .text)
        rangeInfo = try container.decodeIfPresent(String.self, forKey: .rangeInfo)?.nilIfEmpty
        if let rawStyle = try container.decodeIfPresent(String.self, forKey: .style),
           let decodedStyle = RDEPUBHighlightStyle(rawValue: rawStyle) {
            style = decodedStyle
        } else {
            style = .highlight
        }
        color = try container.decodeIfPresent(String.self, forKey: .color) ?? "#F8E16C"
        note = try container.decodeIfPresent(String.self, forKey: .note)?.nilIfEmpty
        createdAt = try container.decodeIfPresent(Date.self, forKey: .createdAt) ?? Date()
    }

    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(id, forKey: .id)
        try container.encodeIfPresent(bookIdentifier, forKey: .bookIdentifier)
        try container.encode(location, forKey: .location)
        try container.encode(text, forKey: .text)
        try container.encodeIfPresent(rangeInfo, forKey: .rangeInfo)
        try container.encode(style, forKey: .style)
        try container.encode(color, forKey: .color)
        try container.encodeIfPresent(note, forKey: .note)
        try container.encode(createdAt, forKey: .createdAt)
    }

    public var annotation: RDEPUBAnnotation {
        RDEPUBAnnotation(highlight: self)
    }
}

public struct RDEPUBBookmark: Codable, Equatable {

    public var id: String

    public var bookIdentifier: String?

    public var location: RDEPUBLocation

    public var rangeInfo: String?

    public var chapterTitle: String?

    public var note: String?

    public var createdAt: Date

    public init(
        id: String = UUID().uuidString,
        bookIdentifier: String? = nil,
        location: RDEPUBLocation,
        rangeInfo: String? = nil,
        chapterTitle: String? = nil,
        note: String? = nil,
        createdAt: Date = Date()
    ) {
        self.id = id
        self.bookIdentifier = bookIdentifier
        self.location = location
        self.rangeInfo = rangeInfo?.nilIfEmpty
        self.chapterTitle = chapterTitle?.nilIfEmpty
        self.note = note?.nilIfEmpty
        self.createdAt = createdAt
    }

    public var hasNote: Bool {
        note?.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty == false
    }

    public var annotation: RDEPUBAnnotation {
        RDEPUBAnnotation(bookmark: self)
    }
}

public struct RDEPUBAnnotation: Codable, Equatable {
    public var id: String
    public var bookIdentifier: String?
    public var kind: RDEPUBAnnotationKind
    public var location: RDEPUBLocation
    public var text: String?
    public var rangeInfo: String?
    public var color: String?
    public var chapterTitle: String?
    public var note: String?
    public var createdAt: Date

    public init(
        id: String = UUID().uuidString,
        bookIdentifier: String? = nil,
        kind: RDEPUBAnnotationKind,
        location: RDEPUBLocation,
        text: String? = nil,
        rangeInfo: String? = nil,
        color: String? = nil,
        chapterTitle: String? = nil,
        note: String? = nil,
        createdAt: Date = Date()
    ) {
        self.id = id
        self.bookIdentifier = bookIdentifier
        self.kind = kind
        self.location = location
        self.text = text?.nilIfEmpty
        self.rangeInfo = rangeInfo?.nilIfEmpty
        self.color = color?.nilIfEmpty
        self.chapterTitle = chapterTitle?.nilIfEmpty
        self.note = note?.nilIfEmpty
        self.createdAt = createdAt
    }

    public init(highlight: RDEPUBHighlight) {
        self.init(
            id: highlight.id,
            bookIdentifier: highlight.bookIdentifier,
            kind: highlight.style == .underline ? .underline : .highlight,
            location: highlight.location,
            text: highlight.text,
            rangeInfo: highlight.rangeInfo,
            color: highlight.color,
            chapterTitle: nil,
            note: highlight.note,
            createdAt: highlight.createdAt
        )
    }

    public init(bookmark: RDEPUBBookmark) {
        self.init(
            id: bookmark.id,
            bookIdentifier: bookmark.bookIdentifier,
            kind: .bookmark,
            location: bookmark.location,
            text: nil,
            rangeInfo: bookmark.rangeInfo,
            color: nil,
            chapterTitle: bookmark.chapterTitle,
            note: bookmark.note,
            createdAt: bookmark.createdAt
        )
    }

    public var bookmark: RDEPUBBookmark? {
        guard kind == .bookmark else { return nil }
        return RDEPUBBookmark(
            id: id,
            bookIdentifier: bookIdentifier,
            location: location,
            rangeInfo: rangeInfo,
            chapterTitle: chapterTitle,
            note: note,
            createdAt: createdAt
        )
    }

    public var highlight: RDEPUBHighlight? {
        guard kind == .highlight || kind == .underline,
              let text else {
            return nil
        }
        return RDEPUBHighlight(
            id: id,
            bookIdentifier: bookIdentifier,
            location: location,
            text: text,
            rangeInfo: rangeInfo,
            style: kind == .underline ? .underline : .highlight,
            color: color ?? "#F8E16C",
            note: note,
            createdAt: createdAt
        )
    }
}