<?php

declare(strict_types=1);

return [
    'queue' => env('DISCOVERY_QUEUE', env('RECOMMENDATIONS_QUEUE', env('VISION_QUEUE', 'default'))),

    // Versioned from day one for safe future migrations/experiments.
    'profile_version' => env('DISCOVERY_PROFILE_VERSION', 'profile-v1'),
    'event_version' => env('DISCOVERY_EVENT_VERSION', 'event-v1'),
    'algo_version' => env('DISCOVERY_ALGO_VERSION', env('RECOMMENDATIONS_ALGO_VERSION', 'clip-cosine-v1')),
    'cache_version' => env('DISCOVERY_CACHE_VERSION', 'cache-v1'),

    'decay' => [
        // Exponential half-life: score * 0.5 every N hours.
        'half_life_hours' => (float) env('DISCOVERY_DECAY_HALF_LIFE_HOURS', 72),
    ],

    // Baseline event contribution weights.
    'weights' => [
        'view' => (float) env('DISCOVERY_WEIGHT_VIEW', 1.0),
        'click' => (float) env('DISCOVERY_WEIGHT_CLICK', 2.0),
        'favorite' => (float) env('DISCOVERY_WEIGHT_FAVORITE', 4.0),
        'download' => (float) env('DISCOVERY_WEIGHT_DOWNLOAD', 3.0),
    ],

    // Recommendation cache TTL in minutes (schema foundation only for now).
    'cache_ttl_minutes' => (int) env('DISCOVERY_CACHE_TTL_MINUTES', 60),

    // Phase 8B: versioned ranking blend weights.
    // Blend components: w1=interest, w2=recency, w3=popularity, w4=novelty.
    'ranking' => [
        'default_weights' => [
            'version' => env('DISCOVERY_RANKING_WEIGHTS_VERSION', 'rank-w-v1'),
            'w1' => (float) env('DISCOVERY_RANKING_W1', 0.65),
            'w2' => (float) env('DISCOVERY_RANKING_W2', 0.20),
            'w3' => (float) env('DISCOVERY_RANKING_W3', 0.10),
            'w4' => (float) env('DISCOVERY_RANKING_W4', 0.05),
        ],

        // Per-algo overrides for safe rollout by algo_version.
        'algo_weight_sets' => [
            'clip-cosine-v1' => [
                'version' => env('DISCOVERY_RANKING_WEIGHTS_VERSION_CLIP_COSINE_V1', 'rank-w-v1'),
                'w1' => (float) env('DISCOVERY_RANKING_W1_CLIP_COSINE_V1', 0.65),
                'w2' => (float) env('DISCOVERY_RANKING_W2_CLIP_COSINE_V1', 0.20),
                'w3' => (float) env('DISCOVERY_RANKING_W3_CLIP_COSINE_V1', 0.10),
                'w4' => (float) env('DISCOVERY_RANKING_W4_CLIP_COSINE_V1', 0.05),
            ],
            'clip-cosine-v2' => [
                'version' => env('DISCOVERY_RANKING_WEIGHTS_VERSION_CLIP_COSINE_V2', 'rank-w-v2-prod-1'),
                'w1' => (float) env('DISCOVERY_RANKING_W1_CLIP_COSINE_V2', 0.52),
                'w2' => (float) env('DISCOVERY_RANKING_W2_CLIP_COSINE_V2', 0.23),
                'w3' => (float) env('DISCOVERY_RANKING_W3_CLIP_COSINE_V2', 0.15),
                'w4' => (float) env('DISCOVERY_RANKING_W4_CLIP_COSINE_V2', 0.10),
            ],
        ],
    ],

    // Phase 8 production rollout gates (deterministic user bucketing).
    'rollout' => [
        'enabled' => (bool) env('DISCOVERY_ROLLOUT_ENABLED', false),
        'baseline_algo_version' => env('DISCOVERY_ROLLOUT_BASELINE_ALGO_VERSION', 'clip-cosine-v1'),
        'candidate_algo_version' => env('DISCOVERY_ROLLOUT_CANDIDATE_ALGO_VERSION', 'clip-cosine-v2'),

        // One of: g10, g50, g100.
        'active_gate' => env('DISCOVERY_ROLLOUT_ACTIVE_GATE', 'g10'),
        'gates' => [
            'g10' => [
                'name' => '10%',
                'percentage' => (int) env('DISCOVERY_ROLLOUT_GATE_10_PERCENT', 10),
            ],
            'g50' => [
                'name' => '50%',
                'percentage' => (int) env('DISCOVERY_ROLLOUT_GATE_50_PERCENT', 50),
            ],
            'g100' => [
                'name' => '100%',
                'percentage' => (int) env('DISCOVERY_ROLLOUT_GATE_100_PERCENT', 100),
            ],
        ],

        // Emergency rollback toggle: force all traffic to one algo_version.
        'force_algo_version' => env('DISCOVERY_FORCE_ALGO_VERSION', ''),

        // Guardrails (used operationally in runbook and dashboards).
        'monitoring_thresholds' => [
            'ctr_warn_drop_pct' => (float) env('DISCOVERY_ROLLOUT_WARN_CTR_DROP_PCT', 3.0),
            'ctr_rollback_drop_pct' => (float) env('DISCOVERY_ROLLOUT_ROLLBACK_CTR_DROP_PCT', 5.0),
            'long_dwell_warn_drop_pct' => (float) env('DISCOVERY_ROLLOUT_WARN_LONG_DWELL_DROP_PCT', 4.0),
            'long_dwell_rollback_drop_pct' => (float) env('DISCOVERY_ROLLOUT_ROLLBACK_LONG_DWELL_DROP_PCT', 8.0),
            'diversity_warn_concentration_rise_pct' => (float) env('DISCOVERY_ROLLOUT_WARN_DIVERSITY_CONCENTRATION_RISE_PCT', 10.0),
            'diversity_rollback_concentration_rise_pct' => (float) env('DISCOVERY_ROLLOUT_ROLLBACK_DIVERSITY_CONCENTRATION_RISE_PCT', 15.0),
        ],
    ],

    // Offline evaluation objective weights (manual/data-driven tuning).
    'evaluation' => [
        'objective_weights' => [
            'ctr' => (float) env('DISCOVERY_EVAL_WEIGHT_CTR', 0.45),
            'save_rate' => (float) env('DISCOVERY_EVAL_WEIGHT_SAVE_RATE', 0.35),
            'long_dwell_share' => (float) env('DISCOVERY_EVAL_WEIGHT_LONG_DWELL', 0.25),
            'bounce_rate_penalty' => (float) env('DISCOVERY_EVAL_WEIGHT_BOUNCE_PENALTY', 0.15),
        ],
        // Temporary switch: keep save_rate visible but exclude it from objective score.
        'save_rate_informational' => (bool) env('DISCOVERY_EVAL_SAVE_RATE_INFORMATIONAL', true),
    ],
];