//
//  UsageStats.swift
//  Confab
//
//  All-time usage statistics (aggregated from the messages table)
//
// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
// Copyright (C) 2026 Rune Olsen
//
// This file is part of Confab.
//
// Confab is licensed under the PolyForm Noncommercial License 1.0.0.
// You may use, study, modify, and share it for any noncommercial
// purpose. Commercial use — including selling Confab or any part of
// it, standalone or bundled into another product or service —
// requires a separate commercial license from the copyright holder.
//
// See the LICENSE file or
// <https://polyformproject.org/licenses/noncommercial/1.0.0> for
// the full license text. For commercial licensing, contact Rune
// Olsen via <https://oai.pm>.


import Foundation

struct UsageStats: Sendable {
    var totalMessages: Int
    var totalTokens: Int
    var totalCost: Double
    var hasCostData: Bool
    var firstMessageDate: Date?
    var lastMessageDate: Date?

    nonisolated init(
        totalMessages: Int = 0,
        totalTokens: Int = 0,
        totalCost: Double = 0.0,
        hasCostData: Bool = false,
        firstMessageDate: Date? = nil,
        lastMessageDate: Date? = nil
    ) {
        self.totalMessages = totalMessages
        self.totalTokens = totalTokens
        self.totalCost = totalCost
        self.hasCostData = hasCostData
        self.firstMessageDate = firstMessageDate
        self.lastMessageDate = lastMessageDate
    }

    var totalTokensDisplay: String {
        if totalTokens >= 1_000_000 {
            return String(format: "%.1fM", Double(totalTokens) / 1_000_000)
        } else if totalTokens >= 1000 {
            return String(format: "%.1fK", Double(totalTokens) / 1000)
        } else {
            return "\(totalTokens)"
        }
    }

    var totalCostDisplay: String {
        hasCostData ? String(format: "$%.4f", totalCost) : "N/A"
    }
}

struct ModelUsageStat: Identifiable, Sendable {
    var id: String { modelId }
    let modelId: String
    var messageCount: Int
    var totalTokens: Int
    var totalCost: Double
    var hasCostData: Bool
    var lastUsed: Date

    nonisolated init(
        modelId: String,
        messageCount: Int,
        totalTokens: Int,
        totalCost: Double,
        hasCostData: Bool,
        lastUsed: Date
    ) {
        self.modelId = modelId
        self.messageCount = messageCount
        self.totalTokens = totalTokens
        self.totalCost = totalCost
        self.hasCostData = hasCostData
        self.lastUsed = lastUsed
    }

    var totalTokensDisplay: String {
        if totalTokens >= 1_000_000 {
            return String(format: "%.1fM", Double(totalTokens) / 1_000_000)
        } else if totalTokens >= 1000 {
            return String(format: "%.1fK", Double(totalTokens) / 1000)
        } else {
            return "\(totalTokens)"
        }
    }

    var totalCostDisplay: String {
        hasCostData ? String(format: "$%.4f", totalCost) : "N/A"
    }
}

struct ConversationUsageStat: Identifiable, Sendable {
    let conversationId: UUID
    var id: UUID { conversationId }
    var name: String
    var messageCount: Int
    var totalTokens: Int
    var totalCost: Double
    var hasCostData: Bool

    nonisolated init(
        conversationId: UUID,
        name: String,
        messageCount: Int,
        totalTokens: Int,
        totalCost: Double,
        hasCostData: Bool
    ) {
        self.conversationId = conversationId
        self.name = name
        self.messageCount = messageCount
        self.totalTokens = totalTokens
        self.totalCost = totalCost
        self.hasCostData = hasCostData
    }

    var totalTokensDisplay: String {
        if totalTokens >= 1_000_000 {
            return String(format: "%.1fM", Double(totalTokens) / 1_000_000)
        } else if totalTokens >= 1000 {
            return String(format: "%.1fK", Double(totalTokens) / 1000)
        } else {
            return "\(totalTokens)"
        }
    }

    var totalCostDisplay: String {
        hasCostData ? String(format: "$%.4f", totalCost) : "N/A"
    }
}