//
//  Colors.swift
//  CapCollector
//
//  Created by Christoph on 26.05.20.
//  Copyright © 2020 CH. All rights reserved.
//

import UIKit
import SQLite

extension Database {
    
    enum Colors {
        
        static let table = Table("colors")
        
        static let columnRed = Expression<Double>("red")
        
        static let columnGreen = Expression<Double>("green")
        
        static let columnBlue = Expression<Double>("blue")
        
        static var createQuery: String {
            table.create(ifNotExists: true) { t in
                t.column(Cap.columnId, primaryKey: true)
                t.column(columnRed)
                t.column(columnGreen)
                t.column(columnBlue)
            }
        }
    }
    
    var colors: [Int : UIColor] {
        do {
            let rows = try db.prepare(Database.Colors.table)
            return rows.reduce(into: [:]) { dict, row in
                let id = row[Cap.columnId]
                let r = CGFloat(row[Database.Colors.columnRed])
                let g = CGFloat(row[Database.Colors.columnGreen])
                let b = CGFloat(row[Database.Colors.columnBlue])
                dict[id] = UIColor(red: r, green: g, blue: b, alpha: 1.0)
            }
        } catch {
            log("Failed to load cap colors: \(error)")
            return [:]
        }
    }
    
    var capsWithColors: Set<Int> {
        do {
            let rows = try db.prepare(Database.Colors.table.select(Cap.columnId))
            return Set(rows.map { $0[Cap.columnId]})
        } catch {
            log("Failed to load caps with colors: \(error)")
            return []
        }
    }
    
    var capsWithoutColors: Set<Int> {
        Set(1...capCount).subtracting(capsWithColors)
    }

    func removeColor(for cap: Int) -> Bool {
        do {
            try db.run(Colors.table.filter(Cap.columnId == cap).delete())
            return true
        } catch {
            log("Failed to delete cap color \(cap): \(error)")
            return false
        }
    }
    
    func set(color: UIColor, for cap: Int) -> Bool {
        guard let _ = row(for: cap) else {
            return insert(color: color, for: cap)
        }
        return update(color: color, for: cap)
    }
    
    private func insert(color: UIColor, for cap: Int) -> Bool {
        let (red, green, blue) = color.rgb
        let query = Database.Colors.table.insert(
            Cap.columnId <- cap,
            Database.Colors.columnRed <- red,
            Database.Colors.columnGreen <- green,
            Database.Colors.columnBlue <- blue)
        
        do {
            try db.run(query)
            return true
        } catch {
            log("Failed to insert color for cap \(cap): \(error)")
            return false
        }
    }
    
    private func update(color: UIColor, for cap: Int) -> Bool {
        let (red, green, blue) = color.rgb
        let query = Database.Colors.table.filter(Cap.columnId == cap).update(
            Database.Colors.columnRed <- red,
            Database.Colors.columnGreen <- green,
            Database.Colors.columnBlue <- blue)
        
        do {
            try db.run(query)
            return true
        } catch {
            log("Failed to update color for cap \(cap): \(error)")
            return false
        }
    }
    
    private func row(for cap: Int) -> Row? {
        do {
            return try db.pluck(Database.Colors.table.filter(Cap.columnId == cap))
        } catch {
            log("Failed to get color for cap \(cap): \(error)")
            return nil
        }
    }
    
    func color(for cap: Int) -> UIColor? {
        guard let row = self.row(for: cap) else {
            return nil
        }
        let r = CGFloat(row[Database.Colors.columnRed])
        let g = CGFloat(row[Database.Colors.columnGreen])
        let b = CGFloat(row[Database.Colors.columnBlue])
        return UIColor(red: r, green: g, blue: b, alpha: 1.0)
    }
}