// Theme.swift
// Jarvis — shared design tokens, signal-score fade math, formatting, nav routes.
// Every hex value here is from the spec; nothing is invented.

import SwiftUI

// MARK: - Hex colors

extension Color {
    init(hex: String) {
        let s = hex.trimmingCharacters(in: CharacterSet(charactersIn: "#"))
        var v: UInt64 = 0
        Scanner(string: s).scanHexInt64(&v)
        let r, g, b: Double
        switch s.count {
        case 6:
            r = Double((v >> 16) & 0xFF) / 255
            g = Double((v >> 8) & 0xFF) / 255
            b = Double(v & 0xFF) / 255
        default:
            r = 0; g = 0; b = 0
        }
        self = Color(.sRGB, red: r, green: g, blue: b, opacity: 1)
    }
}

// MARK: - Palette

enum Palette {
    static let orange   = Color("KisaniOrange")     // #FF5C00
    static let black    = Color.black               // #000000
    static let surface  = Color(hex: "111111")
    static let surface2 = Color(hex: "1A1A1A")
    static let hairline = Color(hex: "1A1A1A")

    // health
    static let healthActive  = Color(hex: "2A5A2A")
    static let healthFailing = Color(hex: "AA6600")
    static let healthDead     = Color(hex: "5A1A1A")

    // blocks
    static let consensusBorder = Color(hex: "FF5C00")
    static let consensusFill    = Color(hex: "1F1206")   // dark orange
    static let conflictBorder   = Color(hex: "5A1A1A")   // dark red
    static let conflictFill     = Color(hex: "1A0C0C")   // dark red

    static let cachedGreen = Color(hex: "2A5A2A")
    static let bodyText    = Color(hex: "4A4A4A")
}

// MARK: - Signal-score fade
//
// Spec anchors:
//   stripe : 97 → #FF5C00, fades to #1A1A1A at 0
//   title  : 97 → white,   20 → #444444, 0–19 near invisible
//   score  : 80–100 full orange · 50–79 dimmed orange · 20–49 dark brown · 0–19 near invisible

enum Signal {
    private static func lerp(_ a: (Double, Double, Double),
                             _ b: (Double, Double, Double),
                             _ t: Double) -> Color {
        let t = max(0, min(1, t))
        return Color(.sRGB,
                     red:   a.0 + (b.0 - a.0) * t,
                     green: a.1 + (b.1 - a.1) * t,
                     blue:  a.2 + (b.2 - a.2) * t,
                     opacity: 1)
    }

    /// 3pt left stripe color: #1A1A1A (0) → #FF5C00 (97+).
    static func stripeColor(_ score: Int) -> Color {
        let t = Double(score) / 97.0
        return lerp((0x1A/255, 0x1A/255, 0x1A/255),   // #1A1A1A
                    (0xFF/255, 0x5C/255, 0x00/255),    // #FF5C00
                    t)
    }

    /// Story title color: white (97+) → #444444 (20) → near invisible (0).
    static func titleColor(_ score: Int) -> Color {
        if score >= 97 { return .white }
        if score >= 20 {
            let t = Double(score - 20) / Double(97 - 20)
            return lerp((0x44/255, 0x44/255, 0x44/255), // #444444
                        (1, 1, 1),                       // white
                        t)
        }
        // 0–19 near invisible: #1C1C1C → #444444
        let t = Double(score) / 20.0
        return lerp((0x1C/255, 0x1C/255, 0x1C/255),
                    (0x44/255, 0x44/255, 0x44/255),
                    t)
    }

    /// Signal score number color: stays in orange/brown hue, fades with score.
    /// near-invisible brown (0) → full #FF5C00 (100).
    static func scoreColor(_ score: Int) -> Color {
        let t = Double(score) / 100.0
        return lerp((0x2A/255, 0x18/255, 0x10/255),    // near-invisible brown
                    (0xFF/255, 0x5C/255, 0x00/255),     // #FF5C00
                    t)
    }
}

// MARK: - Topic display

enum Topic {
    static func label(_ slug: String) -> String {
        switch slug.lowercased() {
        case "finance":  return "Finance"
        case "tech":     return "Tech"
        case "politics": return "Politics"
        case "africa":   return "Africa"
        default:         return slug.prefix(1).uppercased() + slug.dropFirst()
        }
    }

    /// Topic pills shown on the home screen.
    static let filters: [(label: String, slug: String?)] = [
        ("All", nil),
        ("Finance", "finance"),
        ("Tech", "tech"),
        ("Politics", "politics"),
        ("Africa", "africa"),
    ]
}

// MARK: - Time formatting

extension Date {
    /// Short relative string e.g. "just now", "3 min", "2 hr", "4 d".
    func timeAgoShort(reference: Date = Date()) -> String {
        let secs = max(0, Int(reference.timeIntervalSince(self)))
        switch secs {
        case 0..<60:        return "just now"
        case 60..<3600:     return "\(secs / 60) min"
        case 3600..<86400:  return "\(secs / 3600) hr"
        default:            return "\(secs / 86400) d"
        }
    }

    /// "08:03" style monospaced clock for timeline / source chips.
    var clockShort: String {
        let f = DateFormatter()
        f.dateFormat = "HH:mm"
        return f.string(from: self)
    }
}

func syncedMinutesAgo(_ date: Date?, reference: Date = Date()) -> String {
    guard let date else { return "never" }
    return date.timeAgoShort(reference: reference)
}

// MARK: - Navigation routes

/// Route into the article reader. Carries the parent story context so the
/// back button can show the truncated headline.
struct ArticleRoute: Hashable {
    let articleId: String
    let storyId: String
    let parentHeadline: String
}