//
//  TrefleMapper.swift
//  PlantGuide
//
//  Created on 2026-01-21.
//

import Foundation

// MARK: - TrefleMapper

/// Maps Trefle API DTOs to domain entities.
///
/// This mapper provides conversion functions for transforming Trefle API
/// responses into PlantCareInfo domain entities and related care requirement types.
/// All mapping functions handle nil/missing data gracefully with sensible defaults.
struct TrefleMapper {

    // MARK: - Primary Mapping

    /// Maps a Trefle species DTO to a PlantCareInfo domain entity.
    ///
    /// This function extracts all available care information from the Trefle species data,
    /// including growth requirements, environmental preferences, and blooming seasons.
    ///
    /// - Parameter species: The detailed species information from the Trefle API.
    /// - Returns: A `PlantCareInfo` domain entity populated with care requirements.
    static func mapToPlantCareInfo(from species: TrefleSpeciesDTO) -> PlantCareInfo {
        let growth = species.growth
        let specifications = species.specifications

        return PlantCareInfo(
            id: UUID(),
            scientificName: species.scientificName,
            commonName: species.commonName,
            lightRequirement: mapToLightRequirement(from: growth?.light),
            wateringSchedule: mapToWateringSchedule(from: growth),
            temperatureRange: mapToTemperatureRange(from: growth),
            fertilizerSchedule: mapToFertilizerSchedule(from: growth),
            humidity: mapToHumidityLevel(from: growth?.atmosphericHumidity),
            growthRate: mapToGrowthRate(from: specifications?.growthRate),
            bloomingSeason: mapToBloomingSeason(from: growth?.bloomMonths),
            additionalNotes: buildAdditionalNotes(from: species),
            sourceURL: URL(string: "https://trefle.io/api/v1/species/\(species.id)"),
            trefleID: species.id
        )
    }

    // MARK: - Light Requirement Mapping

    /// Maps a Trefle light scale value to a LightRequirement enum.
    ///
    /// Trefle uses a 0-10 scale where 0 is full shade and 10 is full sun.
    /// This function maps that scale to the app's LightRequirement categories.
    ///
    /// - Parameter light: The Trefle light value (0-10 scale), or nil if not available.
    /// - Returns: The corresponding `LightRequirement` enum value.
    ///            Defaults to `.partialShade` if the input is nil.
    ///
    /// Mapping:
    /// - 0-2: `.fullShade` - Very low light conditions
    /// - 3-4: `.lowLight` - Low light but not complete shade
    /// - 5-6: `.partialShade` - Moderate, indirect light
    /// - 7-10: `.fullSun` - Direct sunlight for most of the day
    static func mapToLightRequirement(from light: Int?) -> LightRequirement {
        guard let light = light else {
            return .partialShade
        }

        switch light {
        case 0...2:
            return .fullShade
        case 3...4:
            return .lowLight
        case 5...6:
            return .partialShade
        case 7...10:
            return .fullSun
        default:
            return .partialShade
        }
    }

    // MARK: - Watering Schedule Mapping

    /// Maps Trefle growth data to a WateringSchedule.
    ///
    /// This function determines watering frequency and amount based on the plant's
    /// atmospheric and soil humidity requirements. Plants with higher humidity needs
    /// typically require more frequent but lighter watering, while those with lower
    /// needs benefit from less frequent but thorough watering.
    ///
    /// - Parameter growth: The Trefle growth data containing humidity requirements.
    /// - Returns: A `WateringSchedule` with appropriate frequency and amount.
    ///            Defaults to weekly/moderate if growth data is nil.
    ///
    /// Mapping based on humidity levels (0-10 scale):
    /// - High humidity (7-10): Weekly frequency with light watering
    /// - Medium humidity (4-6): Twice weekly with moderate watering
    /// - Low humidity (0-3): Weekly with thorough watering
    static func mapToWateringSchedule(from growth: TrefleGrowthDTO?) -> WateringSchedule {
        guard let growth = growth else {
            return WateringSchedule(frequency: .weekly, amount: .moderate)
        }

        // Use atmospheric humidity as primary indicator, fall back to soil humidity
        let humidityLevel = growth.atmosphericHumidity ?? growth.soilHumidity

        guard let humidity = humidityLevel else {
            return WateringSchedule(frequency: .weekly, amount: .moderate)
        }

        switch humidity {
        case 7...10:
            // High humidity plants need frequent, light watering
            return WateringSchedule(frequency: .weekly, amount: .light)
        case 4...6:
            // Medium humidity plants need regular, moderate watering
            return WateringSchedule(frequency: .twiceWeekly, amount: .moderate)
        case 0...3:
            // Low humidity plants (often drought-tolerant) need less frequent but thorough watering
            return WateringSchedule(frequency: .weekly, amount: .thorough)
        default:
            return WateringSchedule(frequency: .weekly, amount: .moderate)
        }
    }

    // MARK: - Temperature Range Mapping

    /// Maps Trefle growth data to a TemperatureRange.
    ///
    /// This function extracts minimum and maximum temperature tolerances from the
    /// Trefle growth data and determines frost tolerance based on whether the plant
    /// can survive temperatures below 0 degrees Celsius.
    ///
    /// - Parameter growth: The Trefle growth data containing temperature information.
    /// - Returns: A `TemperatureRange` with min/max values and frost tolerance.
    ///            Defaults to 15-30 degrees Celsius if growth data is nil.
    static func mapToTemperatureRange(from growth: TrefleGrowthDTO?) -> TemperatureRange {
        guard let growth = growth else {
            return TemperatureRange(
                minimumCelsius: 15.0,
                maximumCelsius: 30.0,
                optimalCelsius: nil,
                frostTolerant: false
            )
        }

        let minTemp = growth.minimumTemperature?.degC ?? 15.0
        let maxTemp = growth.maximumTemperature?.degC ?? 30.0

        // Calculate optimal as midpoint between min and max if both are available
        let optimalTemp: Double?
        if growth.minimumTemperature?.degC != nil && growth.maximumTemperature?.degC != nil {
            optimalTemp = (minTemp + maxTemp) / 2.0
        } else {
            optimalTemp = nil
        }

        // Plant is frost tolerant if it can survive temperatures below 0 degrees Celsius
        let frostTolerant = minTemp < 0.0

        return TemperatureRange(
            minimumCelsius: minTemp,
            maximumCelsius: maxTemp,
            optimalCelsius: optimalTemp,
            frostTolerant: frostTolerant
        )
    }

    // MARK: - Fertilizer Schedule Mapping

    /// Maps Trefle growth data to a FertilizerSchedule.
    ///
    /// This function determines fertilizer frequency and type based on the plant's
    /// soil nutrient requirements. Plants with higher nutrient needs require more
    /// frequent fertilization, while those with lower needs can use organic fertilizers
    /// applied less frequently.
    ///
    /// - Parameter growth: The Trefle growth data containing soil nutrient requirements.
    /// - Returns: A `FertilizerSchedule` with appropriate frequency and type,
    ///            or nil if soil nutrient data is not available.
    ///
    /// Mapping based on soil nutriment levels (0-10 scale):
    /// - High needs (7-10): Biweekly with balanced fertilizer
    /// - Medium needs (4-6): Monthly with balanced fertilizer
    /// - Low needs (0-3): Quarterly with organic fertilizer
    static func mapToFertilizerSchedule(from growth: TrefleGrowthDTO?) -> FertilizerSchedule? {
        guard let soilNutriments = growth?.soilNutriments else {
            return nil
        }

        switch soilNutriments {
        case 7...10:
            // High nutrient needs - frequent balanced fertilization
            return FertilizerSchedule(frequency: .biweekly, type: .balanced)
        case 4...6:
            // Medium nutrient needs - monthly balanced fertilization
            return FertilizerSchedule(frequency: .monthly, type: .balanced)
        case 0...3:
            // Low nutrient needs - occasional organic fertilization
            return FertilizerSchedule(frequency: .quarterly, type: .organic)
        default:
            return FertilizerSchedule(frequency: .monthly, type: .balanced)
        }
    }

    // MARK: - Humidity Level Mapping

    /// Maps a Trefle atmospheric humidity value to a HumidityLevel enum.
    ///
    /// Trefle uses a 0-10 scale for atmospheric humidity requirements.
    /// This function maps that scale to the app's HumidityLevel categories.
    ///
    /// - Parameter humidity: The Trefle atmospheric humidity value (0-10 scale),
    ///                       or nil if not available.
    /// - Returns: The corresponding `HumidityLevel` enum value, or nil if input is nil.
    ///
    /// Mapping:
    /// - 0-2: `.low` - Below 30% humidity
    /// - 3-5: `.moderate` - 30-50% humidity
    /// - 6-8: `.high` - 50-70% humidity
    /// - 9-10: `.veryHigh` - Above 70% humidity
    static func mapToHumidityLevel(from humidity: Int?) -> HumidityLevel? {
        guard let humidity = humidity else {
            return nil
        }

        switch humidity {
        case 0...2:
            return .low
        case 3...5:
            return .moderate
        case 6...8:
            return .high
        case 9...10:
            return .veryHigh
        default:
            return .moderate
        }
    }

    // MARK: - Growth Rate Mapping

    /// Maps a Trefle growth rate string to a GrowthRate enum.
    ///
    /// Trefle provides growth rate as a string (e.g., "slow", "moderate", "rapid").
    /// This function maps those values to the app's GrowthRate enum.
    ///
    /// - Parameter growthRate: The Trefle growth rate string, or nil if not available.
    /// - Returns: The corresponding `GrowthRate` enum value, or nil if input is nil
    ///            or doesn't match a known value.
    static func mapToGrowthRate(from growthRate: String?) -> GrowthRate? {
        guard let growthRate = growthRate?.lowercased() else {
            return nil
        }

        switch growthRate {
        case "slow":
            return .slow
        case "moderate", "medium":
            return .moderate
        case "rapid", "fast":
            return .fast
        default:
            return nil
        }
    }

    // MARK: - Blooming Season Mapping

    /// Maps Trefle bloom months to an array of Season values.
    ///
    /// Trefle provides bloom months as an array of three-letter month abbreviations
    /// (e.g., ["mar", "apr", "may"]). This function converts those months to the
    /// corresponding seasons based on Northern Hemisphere conventions.
    ///
    /// - Parameter bloomMonths: An array of month abbreviations, or nil if not available.
    /// - Returns: An array of unique `Season` values when the plant blooms,
    ///            or nil if bloom month data is not available.
    ///
    /// Month to Season Mapping (Northern Hemisphere):
    /// - December, January, February: `.winter`
    /// - March, April, May: `.spring`
    /// - June, July, August: `.summer`
    /// - September, October, November: `.fall`
    static func mapToBloomingSeason(from bloomMonths: [String]?) -> [Season]? {
        guard let bloomMonths = bloomMonths, !bloomMonths.isEmpty else {
            return nil
        }

        var seasons = Set<Season>()

        for month in bloomMonths {
            if let season = monthToSeason(month.lowercased()) {
                seasons.insert(season)
            }
        }

        guard !seasons.isEmpty else {
            return nil
        }

        // Return seasons in natural order: spring, summer, fall, winter
        let orderedSeasons: [Season] = [.spring, .summer, .fall, .winter]
        return orderedSeasons.filter { seasons.contains($0) }
    }

    // MARK: - Private Helpers

    /// Converts a month abbreviation to its corresponding season.
    ///
    /// - Parameter month: A three-letter month abbreviation (lowercase).
    /// - Returns: The corresponding `Season`, or nil if the abbreviation is not recognized.
    private static func monthToSeason(_ month: String) -> Season? {
        switch month {
        case "dec", "jan", "feb":
            return .winter
        case "mar", "apr", "may":
            return .spring
        case "jun", "jul", "aug":
            return .summer
        case "sep", "oct", "nov":
            return .fall
        default:
            return nil
        }
    }

    /// Builds additional care notes from species data.
    ///
    /// This function compiles relevant information that doesn't fit into other
    /// structured fields, such as pH requirements and toxicity warnings.
    ///
    /// - Parameter species: The Trefle species DTO.
    /// - Returns: A string containing additional care notes, or nil if no relevant data.
    private static func buildAdditionalNotes(from species: TrefleSpeciesDTO) -> String? {
        var notes: [String] = []

        // Add pH range information if available
        if let phMin = species.growth?.phMinimum, let phMax = species.growth?.phMaximum {
            notes.append("Soil pH: \(String(format: "%.1f", phMin)) - \(String(format: "%.1f", phMax))")
        } else if let phMin = species.growth?.phMinimum {
            notes.append("Minimum soil pH: \(String(format: "%.1f", phMin))")
        } else if let phMax = species.growth?.phMaximum {
            notes.append("Maximum soil pH: \(String(format: "%.1f", phMax))")
        }

        // Add toxicity warning if available
        if let toxicity = species.specifications?.toxicity?.lowercased(), toxicity != "none" {
            notes.append("Toxicity: \(toxicity.capitalized)")
        }

        // Add family information for reference
        if let family = species.family {
            notes.append("Family: \(family)")
        }

        return notes.isEmpty ? nil : notes.joined(separator: ". ")
    }
}