import ByreAPI
import SwiftUI

typealias Schedule = Components.Schemas.Schedule
typealias ScheduleSave = Components.Schemas.ScheduleSave
typealias ScheduleEvery = Components.Schemas.ScheduleEvery
typealias Weekday = Components.Schemas.Weekday

private let weekdayNames: [(Weekday, String, String)] = [
    (.mon, "M", "Mon"), (.tue, "T", "Tue"), (.wed, "W", "Wed"), (.thu, "T", "Thu"), (.fri, "F", "Fri"), (.sat, "S", "Sat"), (.sun, "S", "Sun"),
]

private func twoDigits(_ n: Int) -> String {
    n < 10 ? "0\(n)" : "\(n)"
}

private func clock(_ hour: Int, _ minute: Int) -> String {
    "\(hour):\(twoDigits(minute))"
}

private func ordinal(_ n: Int) -> String {
    let suffix = (11...13).contains(n % 100) ? "th" : [1: "st", 2: "nd", 3: "rd"][n % 10] ?? "th"
    return "\(n)\(suffix)"
}

func scheduleTiming(_ sc: Schedule) -> String {
    let at = clock(sc.hour, sc.minute)
    switch sc.every {
    case .hour:
        return "Every hour at :\(twoDigits(sc.minute))"
    case .day:
        return "Daily at \(at)"
    case .week:
        let days = Set(sc.weekdays)
        if days.count == 7 {
            return "Daily at \(at)"
        }
        if days == [.mon, .tue, .wed, .thu, .fri] {
            return "Weekdays at \(at)"
        }
        if days == [.sat, .sun] {
            return "Weekends at \(at)"
        }
        let names = weekdayNames.filter { days.contains($0.0) }.map(\.2)
        return names.count == 1 ? "\(names[0])days at \(at)" : "\(names.joined(separator: ", ")) at \(at)"
    case .month:
        return "Monthly on the \(ordinal(sc.dayOfMonth)) at \(at)"
    }
}

private let nextRunFormat: DateFormatter = {
    let f = DateFormatter()
    f.setLocalizedDateFormatFromTemplate("EEE MMM d jmm")
    return f
}()

struct ScheduleRows: View {
    let project: Project
    @Environment(Store.self) private var store
    @Environment(Overlays.self) private var overlays

    var body: some View {
        let list = store.schedules[project.id] ?? []
        if list.isEmpty {
            Text("No schedules.")
                .foregroundStyle(Palette.muted)
                .padding(.horizontal, 10)
                .padding(.vertical, 6)
        }
        VStack(alignment: .leading, spacing: 0) {
            ForEach(list, id: \.id) { sc in
                HoverRow {
                    Task {
                        await editSchedule(project, sc, store, overlays)
                    }
                } content: {
                    Text(sc.title)
                        .lineLimit(1)
                        .truncationMode(.tail)
                        .frame(maxWidth: .infinity, alignment: .leading)
                    Text(scheduleTiming(sc))
                        .font(Fonts.font(11))
                        .foregroundStyle(Palette.muted)
                    Text("next \(nextRunFormat.string(from: sc.nextRun))")
                        .font(Fonts.font(11))
                        .foregroundStyle(Palette.muted)
                }
                .help(sc.workflow.isEmpty ? "Runs one agent on \(sc.model)" : "Runs workflow \(sc.workflow)")
            }
        }
        .padding(.bottom, 8)
    }
}

@MainActor
@Observable
private final class ScheduleDraft {
    var title: String
    var every: ScheduleEvery
    var weekdays: Set<Weekday>
    var hour: Int
    var minute: Int
    var dayOfMonth: Int
    var workflow: String
    var model: String
    var prompt: String
    var workflows: [String] = []
    var failure = ""

    init(_ sc: Schedule?, defaultModel: String) {
        title = sc?.title ?? ""
        every = sc?.every ?? .week
        weekdays = Set(sc?.weekdays ?? [.mon])
        hour = sc?.hour ?? 9
        minute = sc?.minute ?? 0
        dayOfMonth = sc.map { $0.dayOfMonth == 0 ? 1 : $0.dayOfMonth } ?? 1
        workflow = sc?.workflow ?? ""
        model = sc.map { $0.model.isEmpty ? defaultModel : $0.model } ?? defaultModel
        prompt = sc?.prompt ?? ""
    }

    var valid: Bool {
        !trimmed(title).isEmpty && (every != .week || !weekdays.isEmpty) && (!workflow.isEmpty || !trimmed(prompt).isEmpty)
    }

    var save: ScheduleSave {
        ScheduleSave(
            title: title,
            every: every,
            weekdays: every == .week ? weekdayNames.map(\.0).filter { weekdays.contains($0) } : nil,
            hour: every == .hour ? 0 : hour,
            minute: minute,
            dayOfMonth: every == .month ? dayOfMonth : nil,
            prompt: prompt,
            model: workflow.isEmpty ? model : nil,
            workflow: workflow.isEmpty ? nil : workflow
        )
    }
}

@MainActor
func editSchedule(_ project: Project, _ existing: Schedule?, _ store: Store, _ overlays: Overlays) async {
    let draft = ScheduleDraft(existing, defaultModel: store.defaultModel)
    Task {
        draft.workflows = (try? await store.api.client.listWorkflows().ok.body.json.map(\.name)) ?? []
    }
    while true {
        let buttons = existing == nil
            ? [ModalButton(label: "Cancel", value: "cancel"), ModalButton(label: "Create", value: "save", primary: true)]
            : [ModalButton(label: "Delete", value: "delete", danger: true), ModalButton(label: "Cancel", value: "cancel"), ModalButton(label: "Save", value: "save", primary: true)]
        let choice = await overlays.showModal(ScheduleEditor(draft: draft, project: project), buttons, inPane: true, canSubmit: { draft.valid })
        switch choice {
        case "save":
            do {
                if let existing {
                    _ = try await store.api.client.updateSchedule(path: .init(scheduleId: existing.id), body: .json(draft.save)).ok.body.json
                } else {
                    _ = try await store.api.client.createSchedule(path: .init(projectId: project.id), body: .json(draft.save)).created.body.json
                }
                return
            } catch {
                draft.failure = errorText(error)
            }
        case "delete":
            guard let existing, await overlays.showConfirm(["Delete the schedule \"\(existing.title)\"? Tasks it already created stay."], action: "Delete", danger: true, inPane: true) else {
                continue
            }
            do {
                _ = try await store.api.client.deleteSchedule(path: .init(scheduleId: existing.id)).noContent
            } catch {
                overlays.showAlert(errorText(error))
            }
            return
        default:
            return
        }
    }
}

private struct ScheduleEditor: View {
    @Bindable var draft: ScheduleDraft
    let project: Project

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Schedule a task in \(project.name), started from \(project.defaultBranch). Times are the server's.")
                .foregroundStyle(Palette.muted)
                .fixedSize(horizontal: false, vertical: true)
            TextField("Task title", text: $draft.title)
                .modifier(FieldStyle())
            HStack(alignment: .firstTextBaseline, spacing: 8) {
                Text("Every").foregroundStyle(Palette.muted)
                ChoiceMenu(value: $draft.every, options: [(.hour, "hour"), (.day, "day"), (.week, "week"), (.month, "month")])
                if draft.every == .week {
                    Text("on").foregroundStyle(Palette.muted)
                    HStack(spacing: 4) {
                        ForEach(weekdayNames, id: \.0) { day in
                            dayToggle(day)
                        }
                    }
                }
                if draft.every == .month {
                    Text("on the").foregroundStyle(Palette.muted)
                    ChoiceMenu(value: $draft.dayOfMonth, options: (1...31).map { ($0, ordinal($0)) })
                }
                Text("at").foregroundStyle(Palette.muted)
                if draft.every == .hour {
                    ChoiceMenu(value: $draft.minute, options: (0...59).map { ($0, ":\(twoDigits($0))") })
                } else {
                    ChoiceMenu(value: $draft.hour, options: (0...23).map { ($0, String($0)) })
                    Text(":").foregroundStyle(Palette.muted)
                    ChoiceMenu(value: $draft.minute, options: (0...59).map { ($0, twoDigits($0)) })
                }
            }
            HStack(alignment: .firstTextBaseline, spacing: 8) {
                Text("Run").foregroundStyle(Palette.muted)
                let names = draft.workflow.isEmpty || draft.workflows.contains(draft.workflow) ? draft.workflows : [draft.workflow] + draft.workflows
                ChoiceMenu(value: $draft.workflow, options: [("", "one agent")] + names.map { ($0, "workflow \($0)") })
                if draft.workflow.isEmpty {
                    Text("on").foregroundStyle(Palette.muted)
                    ModelPicker(model: $draft.model)
                }
            }
            Text(draft.workflow.isEmpty ? "The agent's first message: a complete brief, since it sees nothing else." : "The workflow's brief, given to every stage (optional).")
                .foregroundStyle(Palette.muted)
                .fixedSize(horizontal: false, vertical: true)
            PromptEditor(text: $draft.prompt)
            if !draft.failure.isEmpty {
                Text(draft.failure)
                    .foregroundStyle(Palette.danger)
                    .textSelection(.enabled)
                    .fixedSize(horizontal: false, vertical: true)
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }

    private func dayToggle(_ day: (Weekday, String, String)) -> some View {
        let on = draft.weekdays.contains(day.0)
        return Button {
            if on {
                draft.weekdays.remove(day.0)
            } else {
                draft.weekdays.insert(day.0)
            }
        } label: {
            Text(day.1)
                .font(Fonts.font(11, weight: on ? 700 : 400))
                .foregroundStyle(on ? Palette.text : Palette.muted)
                .frame(width: 20, height: 20)
                .background(on ? Palette.accentTint : .clear, in: RoundedRectangle(cornerRadius: 4))
                .overlay(RoundedRectangle(cornerRadius: 4).stroke(on ? Palette.accent : Palette.border))
                .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .help(day.2)
        .accessibilityLabel(day.2)
    }
}