// Shared model for the menu bar and the floating panel: herdr's palette and
// status vocabulary, agent rows read from tmux, and the focus action.

import AppKit

// MARK: herdr's palette (catppuccin mocha on dark, latte on light)

func herdrColor(dark: (CGFloat, CGFloat, CGFloat), light: (CGFloat, CGFloat, CGFloat)) -> NSColor {
    NSColor(name: nil) { appearance in
        let isDark = appearance.bestMatch(from: [.darkAqua, .aqua]) == .darkAqua
        let (r, g, b) = isDark ? dark : light
        return NSColor(srgbRed: r / 255, green: g / 255, blue: b / 255, alpha: 1)
    }
}

let herdrRed = herdrColor(dark: (243, 139, 168), light: (210, 15, 57))
let herdrTeal = herdrColor(dark: (148, 226, 213), light: (23, 146, 153))
let herdrYellow = herdrColor(dark: (249, 226, 175), light: (223, 142, 29))
let herdrGreen = herdrColor(dark: (166, 227, 161), light: (64, 160, 43))
let herdrGray = herdrColor(dark: (108, 112, 134), light: (156, 160, 176))
/// Not a status color: marks a high-importance agent.
let herdrPeach = herdrColor(dark: (250, 179, 135), light: (254, 100, 11))

/// herdr's mocha text colors, fixed (not appearance-dependent) for the
/// always-dark floating panel.
func mocha(_ r: CGFloat, _ g: CGFloat, _ b: CGFloat, _ a: CGFloat = 1) -> NSColor {
    NSColor(srgbRed: r / 255, green: g / 255, blue: b / 255, alpha: a)
}
let mochaText = mocha(205, 214, 244)
let mochaSubtext = mocha(166, 173, 200)
let mochaOverlay = mocha(108, 112, 134)
let mochaBlue = mocha(137, 180, 250)
let mochaRed = mocha(243, 139, 168)
let mochaYellow = mocha(249, 226, 175)
let mochaSurface = mocha(69, 71, 90)

// MARK: herdr's status vocabulary

enum Status: String {
    case blocked, done, working, idle, unknown

    var symbol: String {
        switch self {
        case .blocked: return "×"
        case .done: return "✓"
        case .working: return "◐"
        case .idle: return "○"
        case .unknown: return "·"
        }
    }

    var color: NSColor {
        switch self {
        case .blocked: return herdrRed
        case .done: return herdrTeal
        case .working: return herdrYellow
        case .idle: return herdrGreen
        case .unknown: return herdrGray
        }
    }

    var priority: Int {
        switch self {
        case .blocked: return 4
        case .done: return 3
        case .working: return 2
        case .idle: return 1
        case .unknown: return 0
        }
    }
}

/// The agent's importance (`@dingger_importance`, unset for normal): it
/// orders agents within a status, and a low agent makes no sound.
enum Importance: Int {
    case low = 0, normal = 1, high = 2

    init(option: String) {
        switch option {
        case "high": self = .high
        case "low": self = .low
        default: self = .normal
        }
    }
}

struct Row: Equatable {
    let paneId: String
    let agent: String
    /// What the agent works on (its session/task name), if it has one.
    let name: String
    let status: Status
    let session: String
    let window: String
    let since: Int
    /// The pane's working directory, home as "~".
    var path: String = ""
    var importance: Importance = .normal
    /// The draft in the agent's input box, as one line (`@dingger_draft`).
    var draft: String = ""
    /// The user looks at this pane: its window is active in an attached session.
    var attended: Bool = false
    /// What its session spent today (UTC), in dollars (`@dingger_cost`).
    var cost: Double = 0
    /// How full its context window is, in percent (`@dingger_context`), as
    /// pi's footer shows it; nil when unknown.
    var context: Double? = nil

    var location: String { "\(session) · \(window)" }
    /// A draft left behind: where the user looks, they may be typing it.
    var forgottenDraft: Bool { !draft.isEmpty && !attended }
    var waiting: Bool { status == .blocked || status == .done }
    /// Only an agent you have seen can be marked unread (done again).
    var canMarkUnread: Bool { status == .idle }

    /// The row's title text: the agent's name, or its harness when unnamed.
    var label: String {
        guard !name.isEmpty else { return agent }
        return name.count > 80 ? String(name.prefix(79)) + "…" : name
    }

    /// The title's text as plain text: `! ` marks a high agent, `✎ ` a
    /// forgotten draft.
    var markedLabel: String { (importance == .high ? "! " : "") + (forgottenDraft ? "✎ " : "") + label }

    /// The menu's dim second line: where it runs, which harness, whether
    /// it is low, how long it waits, what it spent today, and how full its
    /// context is.
    var subtitle: String {
        var parts = [place]
        if cost >= 0.005 { parts.append(dollars(cost)) }
        if let context { parts.append(contextText(context)) }
        return parts.joined(separator: " · ")
    }

    /// The panel's second line, before its cost and context columns.
    var place: String {
        var parts = [location, agent]
        if importance == .low { parts.append("low") }
        if waiting, since != Int.max {
            parts.append("\(status.rawValue) \(elapsed(sinceMs: since))")
        }
        return parts.joined(separator: " · ")
    }

    /// The panel's row as text: its columns, then cost and context.
    var panelText: String {
        let right = [cost >= 0.005 ? dollars(cost) : nil, context.map(contextText)].compactMap { $0 }
        return "\(status.symbol) \(status.rawValue)\t\(markedLabel)\t\(place)"
            + (right.isEmpty ? "" : "\t" + right.joined(separator: " "))
    }
}

/// "10%".
func contextText(_ value: Double) -> String { "\(Int(value.rounded()))%" }

/// The context meter's color: as pi's footer, yellow above 70% and red
/// above 90%; nil below.
func contextWarning(_ value: Double) -> NSColor? {
    value > 90 ? mochaRed : value > 70 ? mochaYellow : nil
}

/// "$0.42", "$19.85"; whole dollars from $100: "$1,967".
func dollars(_ amount: Double) -> String {
    if amount < 99.995 { return String(format: "$%.2f", amount) }
    let formatter = NumberFormatter()
    formatter.numberStyle = .decimal
    formatter.locale = Locale(identifier: "en_US")
    formatter.maximumFractionDigits = 0
    return "$" + (formatter.string(from: NSNumber(value: amount.rounded())) ?? String(Int(amount.rounded())))
}

/// What pi agents spent today, this week, and this month (UTC), closed
/// agents included, as the daemon counts it (`@dingger_cost_today`, ...).
struct Spend: Equatable {
    let today: Double
    let week: Double
    let month: Double

    var isEmpty: Bool { today < 0.005 && week < 0.005 && month < 0.005 }

    /// "$8.86 today · $457 this week · $8.86 this month"
    var line: String {
        "\(dollars(today)) today · \(dollars(week)) this week · \(dollars(month)) this month"
    }
}

func fetchSpend() -> Spend {
    let amount = { (name: String) in
        Double(tmux(["show-options", "-gv", name])?.trimmingCharacters(in: .whitespacesAndNewlines) ?? "") ?? 0
    }
    return Spend(today: amount("@dingger_cost_today"), week: amount("@dingger_cost_week"),
                 month: amount("@dingger_cost_month"))
}

/// Compact age: "now", "4m", "2h", "3d".
func elapsed(sinceMs: Int) -> String {
    let seconds = max(0, Int(Date().timeIntervalSince1970) - sinceMs / 1000)
    switch seconds {
    case ..<60: return "now"
    case ..<3600: return "\(seconds / 60)m"
    case ..<86400: return "\(seconds / 3600)h"
    default: return "\(seconds / 86400)d"
    }
}

// MARK: tmux and dingger access

let environment = ProcessInfo.processInfo.environment

func run(_ path: String, _ args: [String]) -> String? {
    let process = Process()
    process.executableURL = URL(fileURLWithPath: path)
    process.arguments = args
    let pipe = Pipe()
    process.standardOutput = pipe
    process.standardError = FileHandle.nullDevice
    do {
        try process.run()
    } catch {
        return nil
    }
    let data = pipe.fileHandleForReading.readDataToEndOfFile()
    process.waitUntilExit()
    guard process.terminationStatus == 0 else { return nil }
    return String(data: data, encoding: .utf8)
}

/// Like run(), but reports why a command failed: exit status and stderr.
func runReporting(_ path: String, _ args: [String]) -> (ok: Bool, output: String) {
    let process = Process()
    process.executableURL = URL(fileURLWithPath: path)
    process.arguments = args
    let out = Pipe(), err = Pipe()
    process.standardOutput = out
    process.standardError = err
    do {
        try process.run()
    } catch {
        return (false, "cannot run \(path): \(error.localizedDescription)")
    }
    let stdout = String(data: out.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8) ?? ""
    let stderr = String(data: err.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8) ?? ""
    process.waitUntilExit()
    let text = (stdout + stderr).trimmingCharacters(in: .whitespacesAndNewlines)
    return (process.terminationStatus == 0, text)
}

/// The tmux binary: launchd gives apps a PATH without Homebrew, so look in
/// the usual places.
let tmuxBinary: String = environment["DINGGER_TMUX"]
    ?? ["/opt/homebrew/bin/tmux", "/usr/local/bin/tmux", "/usr/bin/tmux"]
        .first { FileManager.default.isExecutableFile(atPath: $0) } ?? "/opt/homebrew/bin/tmux"

func tmux(_ args: [String]) -> String? {
    var all = ["-u"]
    if let socket = environment["DINGGER_TMUX_SOCKET"] {
        all += ["-L", socket]
    }
    return run(tmuxBinary, all + args)
}

let dinggerBinary = environment["DINGGER_BIN"] ?? (NSHomeDirectory() + "/.local/bin/dingger")

// MARK: restore offer

/// tmux sessions the daemon offers to restore after tmux stopped
/// (`offer.json`, written by `dingger watch`).
struct RestoreOffer: Decodable, Equatable {
    struct Session: Decodable, Equatable {
        let name: String
        let windows: Int
        let panes: Int
        let agents: Int
    }
    let saved_at: Int
    let sessions: [Session]
    let agents: Int
    let interrupted: Int

    /// "Restore 9 sessions · 22 agents"
    var title: String {
        var text = "Restore \(sessions.count) \(sessions.count == 1 ? "session" : "sessions")"
        if agents > 0 { text += " · \(agents) \(agents == 1 ? "agent" : "agents")" }
        return text
    }

    /// "saved 13:01 · 1 was mid-turn"
    var detail: String {
        let formatter = DateFormatter()
        let saved = Date(timeIntervalSince1970: TimeInterval(saved_at) / 1000)
        formatter.dateFormat = Calendar.current.isDateInToday(saved) ? "HH:mm" : "MMM d, HH:mm"
        var parts = ["tmux stopped · saved \(formatter.string(from: saved))"]
        if interrupted > 0 { parts.append("\(interrupted) \(interrupted == 1 ? "was" : "were") mid-turn") }
        return parts.joined(separator: " · ")
    }
}

let stateDirectory = environment["DINGGER_STATE_DIR"] ?? (NSHomeDirectory() + "/.local/state/dingger")

func fetchRestoreOffer() -> RestoreOffer? {
    guard let data = FileManager.default.contents(atPath: stateDirectory + "/offer.json") else { return nil }
    return try? JSONDecoder().decode(RestoreOffer.self, from: data)
}

// MARK: agents on an old extension

/// pi agents on an old dingger extension, as the daemon counts them:
/// `@dingger_outdated` it can reload, `@dingger_outdated_by_hand` it cannot
/// (an extension from before reloads).
struct OutdatedAgents: Equatable {
    let reloadable: Int
    let byHand: Int

    var isEmpty: Bool { reloadable == 0 && byHand == 0 }
    var canReload: Bool { reloadable > 0 }

    private func agents(_ n: Int) -> String { "\(n) \(n == 1 ? "Agent" : "Agents")" }

    /// "Reload 3 Agents on an Old Extension", or "2 Agents Need /reload".
    var title: String {
        canReload ? "Reload \(agents(reloadable)) on an Old Extension" : "\(agents(byHand)) \(byHand == 1 ? "Needs" : "Need") /reload"
    }

    var detail: String {
        guard canReload else { return "their dingger extension is too old to reload them" }
        let when = "each when idle and off screen"
        return byHand > 0 ? "\(when) · \(byHand) more need /reload" : when
    }
}

func fetchOutdated() -> OutdatedAgents {
    let count = { (name: String) in Int(tmux(["show-options", "-gv", name])?.trimmingCharacters(in: .whitespacesAndNewlines) ?? "") ?? 0 }
    return OutdatedAgents(reloadable: count("@dingger_outdated"), byHand: count("@dingger_outdated_by_hand"))
}

/// Run `dingger <args>` through the user's login shell, the way a terminal
/// starts tmux: restored panes inherit this environment (PATH, LANG), and
/// launchd's is bare. DINGGER_RESTORE_DIRECT runs it directly (tests).
func runDinggerInLoginShell(_ args: [String]) -> (ok: Bool, output: String) {
    if environment["DINGGER_RESTORE_DIRECT"] != nil {
        return runReporting(dinggerBinary, args)
    }
    let shell = getpwuid(getuid()).flatMap { String(validatingUTF8: $0.pointee.pw_shell) } ?? "/bin/zsh"
    return runReporting(shell, ["--login", "-i", "-c", "exec \"$0\" \"$@\"", dinggerBinary] + args)
}

private let home = NSHomeDirectory()

/// Every agent pane: herdr's status priority; idle agents with a forgotten
/// draft before the other idle ones; within a status, the more important
/// first, then done and blocked oldest first (the queue),
/// working and idle most recent first (`@dingger_since`: when the pane
/// entered its status); then by place.
func fetchRows() -> [Row] {
    let format = [
        "#{pane_id}", "#{@agent}", "#{@agent_state}", "#{@dingger_since}", "#{@agent_name}",
        "#{session_name}", "#{window_name}", "#{window_panes}", "#{pane_index}", "#{pane_current_path}",
        "#{@dingger_importance}", "#{window_active}", "#{session_attached}", "#{@dingger_draft}", "#{@dingger_cost}", "#{@dingger_context}",
    ].joined(separator: "\t")
    guard let out = tmux(["list-panes", "-a", "-F", format]) else { return [] }
    let lines = out.split(separator: "\n").map {
        $0.split(separator: "\t", omittingEmptySubsequences: false).map(String.init)
    }
    // Looked at in any of its sessions, as the daemon counts it.
    let attended = Set(lines.filter { $0.count >= 16 && $0[11] == "1" && $0[12] != "0" }.map { $0[0] })
    // A pane in several sessions (a session group, a linked window) is
    // listed once, under its first session, as the daemon counts it.
    var listed = Set<String>()
    let rows: [Row] = lines.compactMap { f in
        guard f.count >= 16, !f[1].isEmpty, listed.insert(f[0]).inserted else { return nil }
        let status = Status(rawValue: f[2]) ?? .unknown
        guard status != .unknown else { return nil }
        let window = (Int(f[7]) ?? 1) > 1 ? "\(f[6]).\(f[8])" : f[6]
        return Row(paneId: f[0], agent: f[1], name: f[4], status: status,
                   session: f[5], window: window, since: Int(f[3]) ?? Int.max,
                   path: f[9].hasPrefix(home) ? "~" + f[9].dropFirst(home.count) : f[9],
                   importance: Importance(option: f[10]), draft: f[13], attended: attended.contains(f[0]),
                   cost: Double(f[14]) ?? 0, context: Double(f[15]))
    }
    return rows.sorted(by: listedBefore)
}

/// The list order (see `fetchRows`).
func listedBefore(_ a: Row, _ b: Row) -> Bool {
    if a.status.priority != b.status.priority { return a.status.priority > b.status.priority }
    if a.status == .idle, a.forgottenDraft != b.forgottenDraft { return a.forgottenDraft }
    if a.importance != b.importance { return a.importance.rawValue > b.importance.rawValue }
    if a.since != b.since {
        // Int.max: never stamped; last either way.
        if a.since == Int.max || b.since == Int.max { return a.since < b.since }
        return a.waiting ? a.since < b.since : a.since > b.since
    }
    return a.location < b.location
}

/// Show the pane and mark it attended; the same code path as the tmux
/// status-line click.
func focus(_ paneId: String) {
    let result = runReporting(dinggerBinary, ["focus", "--pane", paneId])
    if !result.ok { log("jump: dingger focus --pane \(paneId) failed: \(result.output)") }
}

/// Mark an idle agent unread: `dingger unread` returns once it shows as
/// done.
func markAgentUnread(_ paneId: String) {
    let result = runReporting(dinggerBinary, ["unread", "--pane", paneId])
    log("unread: \(paneId) \(result.ok ? "marked" : "failed: \(result.output)")")
}

// MARK: rendering

/// herdr-style summary: `×1 ✓3 ◐2` in priority order; `○` when every agent
/// is idle; `·` when there are none.
func title(for rows: [Row]) -> NSAttributedString {
    let font = NSFont.monospacedDigitSystemFont(ofSize: 13, weight: .medium)
    let text = NSMutableAttributedString()
    for status in [Status.blocked, .done, .working] {
        let count = rows.filter { $0.status == status }.count
        guard count > 0 else { continue }
        if text.length > 0 {
            text.append(NSAttributedString(string: " ", attributes: [.font: font]))
        }
        text.append(NSAttributedString(
            string: "\(status.symbol)\(count)",
            attributes: [.font: font, .foregroundColor: status.color]))
    }
    if text.length == 0 {
        let status: Status = rows.isEmpty ? .unknown : .idle
        text.append(NSAttributedString(
            string: status.symbol, attributes: [.font: font, .foregroundColor: status.color]))
    }
    return text
}

func plainTitle(for rows: [Row]) -> String {
    title(for: rows).string
}

/// The title's characters before the name: the status symbol, the
/// importance column, and the draft mark.
func rowTitlePrefix(_ row: Row) -> String {
    "\(row.status.symbol)  " + importanceMark(row) + " " + draftMark(row)
}

/// `✎ ` before the name of an agent with a forgotten draft.
private func draftMark(_ row: Row) -> String { row.forgottenDraft ? "✎ " : "" }

/// The importance column: `!` for a high agent, a blank otherwise, so every
/// name starts in the same place.
private func importanceMark(_ row: Row) -> String { row.importance == .high ? "!" : " " }

/// How much a low agent's name is dimmed: enough to recede, still legible.
let lowImportanceAlpha: CGFloat = 0.5

/// Row title: the colored status symbol, the importance column (a peach `!`
/// for a high agent), `✎` for a forgotten draft, then the agent's name. Unnamed agents show their
/// harness, dimmed, so it never competes with real names; a low agent's name
/// is dimmed.
func rowTitle(_ row: Row, primary: NSColor = .labelColor,
              secondary: NSColor = .secondaryLabelColor) -> NSAttributedString {
    let font = NSFont.menuFont(ofSize: 0)
    let mono = NSFont.monospacedSystemFont(ofSize: font.pointSize, weight: .medium)
    let text = NSMutableAttributedString()
    text.append(NSAttributedString(
        string: "\(row.status.symbol)  ", attributes: [.font: mono, .foregroundColor: row.status.color]))
    text.append(NSAttributedString(
        string: importanceMark(row) + " ",
        attributes: [.font: NSFont.monospacedSystemFont(ofSize: font.pointSize, weight: .heavy),
                     .foregroundColor: herdrPeach]))
    if row.forgottenDraft {
        text.append(NSAttributedString(string: draftMark(row), attributes: [.font: font, .foregroundColor: primary]))
    }
    let labelColor = row.name.isEmpty ? secondary
        : row.importance == .low ? primary.withAlphaComponent(lowImportanceAlpha) : primary
    text.append(NSAttributedString(
        string: row.label, attributes: [.font: font, .foregroundColor: labelColor]))
    return text
}