//
//  DataControllerGET.swift
//  Feels
//
//  SwiftData READ operations.
//

import SwiftData
import Foundation

extension DataController {
    func getEntry(byDate date: Date) -> MoodEntryModel? {
        let startDate = Calendar.current.startOfDay(for: date)
        let endDate = Calendar.current.date(byAdding: .day, value: 1, to: startDate)!

        var descriptor = FetchDescriptor<MoodEntryModel>(
            predicate: #Predicate { entry in
                entry.forDate >= startDate && entry.forDate <= endDate
            },
            sortBy: [SortDescriptor(\.forDate, order: .forward)]
        )
        descriptor.fetchLimit = 1

        return try? modelContext.fetch(descriptor).first
    }

    func getData(startDate: Date, endDate: Date, includedDays: [Int]) -> [MoodEntryModel] {
        let weekDays = includedDays.isEmpty ? [1, 2, 3, 4, 5, 6, 7] : includedDays

        let descriptor = FetchDescriptor<MoodEntryModel>(
            predicate: #Predicate { entry in
                entry.forDate >= startDate &&
                entry.forDate <= endDate &&
                weekDays.contains(entry.weekDay)
            },
            sortBy: [SortDescriptor(\.forDate, order: .forward)]
        )

        return (try? modelContext.fetch(descriptor)) ?? []
    }

    func splitIntoYearMonth(includedDays: [Int]) -> [Int: [Int: [MoodEntryModel]]] {
        let data = getData(
            startDate: Date(timeIntervalSince1970: 0),
            endDate: Date(),
            includedDays: includedDays
        ).sorted { $0.forDate < $1.forDate }

        guard let earliest = data.first,
              let latest = data.last else { return [:] }

        let calendar = Calendar.current
        let earliestYear = calendar.component(.year, from: earliest.forDate)
        let latestYear = calendar.component(.year, from: latest.forDate)

        var result = [Int: [Int: [MoodEntryModel]]]()

        for year in earliestYear...latestYear {
            var monthData = [Int: [MoodEntryModel]]()

            for month in 1...12 {
                var components = DateComponents()
                components.year = year
                components.month = month
                components.day = 1

                guard let startOfMonth = calendar.date(from: components) else { continue }

                let items = getData(
                    startDate: startOfMonth,
                    endDate: startOfMonth.endOfMonth,
                    includedDays: [1, 2, 3, 4, 5, 6, 7]
                )

                if !items.isEmpty {
                    monthData[month] = items
                }
            }

            result[year] = monthData
        }

        return result
    }
}