import Foundation

/// `visual_timeline.json` (schema 1.1) — the app's primary visual output. Times
/// are seconds relative to session t0. Segments may overlap (crosstalk).
struct VisualTimeline: Codable {
    var schemaVersion = "1.1"
    let sessionId: String
    let app: String
    let adapterVersion: String
    let t0Unix: Double
    let durationSec: Double
    let fpsSampled: Int
    let selfName: String?
    let participants: [Participant]
    let segments: [Segment]
    let visualGaps: [Gap]

    struct Participant: Codable {
        let name: String
        let isSelf: Bool?
        let aliases: [String]?
        enum CodingKeys: String, CodingKey {
            case name
            case isSelf = "is_self"
            case aliases
        }
    }

    struct Segment: Codable, Equatable {
        let start: Double
        let end: Double
        let name: String
        let confidence: Double
        let source: String   // vision | accessibility | fused | mic_vad
    }

    struct Gap: Codable, Equatable {
        let start: Double
        let end: Double
        let reason: String   // minimized | tab_switched
    }

    enum CodingKeys: String, CodingKey {
        case schemaVersion = "schema_version"
        case sessionId = "session_id"
        case app
        case adapterVersion = "adapter_version"
        case t0Unix = "t0_unix"
        case durationSec = "duration_sec"
        case fpsSampled = "fps_sampled"
        case selfName = "self_name"
        case participants
        case segments
        case visualGaps = "visual_gaps"
    }

    /// Write the rich `visual_timeline.json`.
    func write(to url: URL) throws {
        let encoder = JSONEncoder()
        encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
        try encoder.encode(self).write(to: url)
    }

    /// The flat array `label-merge` wants: `[{start,end,name,confidence}]`,
    /// dropping `source`. Slice/rebase to chunk-local seconds happens in Phase 5.
    func flatTimelineData() throws -> Data {
        let flat = segments.map { seg -> [String: Any] in
            ["start": seg.start, "end": seg.end, "name": seg.name, "confidence": seg.confidence]
        }
        return try JSONSerialization.data(withJSONObject: flat, options: [])
    }
}