//! Curated list of Claude models known to work with this CLI.
//! Centralized so the settings dropdown, defaults, and subagent hints agree.

pub const KNOWN_MODELS: &[(&str, &str)] = &[
    ("claude-sonnet-4-6",         "Sonnet 4.6 — balanced (default)"),
    ("claude-opus-4-7",           "Opus 4.7 — most capable"),
    ("claude-opus-4-6",           "Opus 4.6 — previous flagship"),
    ("claude-haiku-4-5-20251001", "Haiku 4.5 — fast"),
];

pub fn default_model() -> &'static str {
    KNOWN_MODELS[0].0
}

/// Returns true for models that support (and require) adaptive thinking:
/// `thinking: {type: "adaptive"}` with NO `budget_tokens` field.
///
/// Per Anthropic's docs as of 2026-04: Opus 4.6+/Sonnet 4.6+ deprecated
/// the fixed-budget `{type: "enabled", budget_tokens: N}` shape. On those
/// models the deprecated shape is silently accepted but returns no
/// thinking content (observed S172 on Opus 4.7). Older models (Opus 4.5,
/// Sonnet 4.5, Haiku, Opus 3.x) still use the enabled+budget shape.
///
/// Adaptive thinking also auto-enables interleaved thinking — no beta
/// header required.
pub fn model_supports_adaptive_thinking(model: &str) -> bool {
    let m = model.to_ascii_lowercase();
    // Only Opus 4.7+ REQUIRES adaptive. Opus 4.6 supports it optionally
    // but works fine with enabled+budget_tokens (and doesn't support the
    // xhigh effort level that adaptive users expect). Keep 4.6 on the
    // legacy path to avoid effort-mapping headaches.
    if m.contains("opus-4-7") || m.contains("opus-4-8") || m.contains("opus-4-9") {
        return true;
    }
    if m.contains("sonnet-4-7") || m.contains("sonnet-4-8") || m.contains("sonnet-4-9") {
        return true;
    }
    // 5.x and beyond — assume adaptive by default.
    if m.contains("opus-5") || m.contains("sonnet-5") || m.contains("haiku-5") {
        return true;
    }
    false
}

/// Maps a SynapsCLI thinking level to an Anthropic `effort` value for models
/// that use adaptive thinking (Opus 4.6+/Sonnet 4.6+). Effort controls
/// thinking depth when `budget_tokens` is unavailable/deprecated.
///
/// "adaptive" as input means "let the model decide" — returns None so the
/// caller omits `output_config.effort` entirely.
pub fn effort_for_thinking_level(level: &str) -> Option<&'static str> {
    match level {
        "low" => Some("low"),
        "medium" | "med" => Some("medium"),
        "high" => Some("high"),
        "xhigh" => Some("xhigh"),
        "adaptive" => None, // model decides
        _ => Some("high"),  // safe default
    }
}

/// Maps a raw `thinking_budget` value to the user-facing level name.
///
/// `0` is the sentinel for "adaptive" (model decides). Positive values
/// bucket into the four fixed tiers. Single source of truth — consumed by
/// Runtime::thinking_level, the request builders in runtime/api.rs, and
/// the status display.
pub fn thinking_level_for_budget(budget: u32) -> &'static str {
    match budget {
        0 => "adaptive",
        1..=2048 => "low",
        2049..=4096 => "medium",
        4097..=16384 => "high",
        _ => "xhigh",
    }
}

/// Default legacy-model thinking budget used when the "adaptive" sentinel
/// (0) leaks into the non-adaptive request path. Matches the "high" tier.
pub const DEFAULT_LEGACY_ADAPTIVE_FALLBACK: u32 = 16384;

/// Returns true for models that *support* opting into the 1M context window
/// via the `context-1m-2025-08-07` beta header.
///
/// Without that header, all current Claude models operate at the default
/// 200k window — including those documented as "1M tokens", because the
/// extended window is gated behind the beta opt-in. This matches Anthropic's
/// own claude-code logic (`modelSupports1M` in src/utils/context.ts).
pub fn model_supports_1m(model: &str) -> bool {
    let m = model.to_ascii_lowercase();
    // Opus 4.6+, Sonnet 4 family. Newer models (5.x) assumed supported.
    m.contains("opus-4-6") || m.contains("opus-4-7")
        || m.contains("opus-4-8") || m.contains("opus-4-9")
        || m.contains("sonnet-4")
        || m.contains("opus-5") || m.contains("sonnet-5")
}

/// Returns the input context window size for a given model, in tokens.
/// Used as the denominator for the chatui context-usage bar and anywhere
/// else the client needs to know how much prompt the model will accept.
///
/// **All models default to 200k** — matching Anthropic's claude-code
/// behavior. Models that support a larger window (Opus 4.6+, Sonnet 4)
/// require explicit opt-in via the `context-1m-2025-08-07` beta header.
/// Without the header, the model operates in 200k mode (better inference
/// quality — context rot at long contexts is real).
///
/// Use [`model_supports_1m`] to check whether a model *can* opt into 1M;
/// the actual decision happens at request time based on the user's
/// `context_window` setting.
pub fn context_window_for_model(_model: &str) -> u64 {
    200_000
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn default_model_is_first_entry() {
        assert_eq!(default_model(), KNOWN_MODELS[0].0);
    }

    #[test]
    fn known_models_has_expected_ids() {
        let ids: Vec<&str> = KNOWN_MODELS.iter().map(|(id, _)| *id).collect();
        assert!(ids.contains(&"claude-opus-4-7"));
        assert!(ids.contains(&"claude-sonnet-4-6"));
        assert!(ids.contains(&"claude-haiku-4-5-20251001"));
    }

    #[test]
    fn descriptions_are_non_empty() {
        for (_, desc) in KNOWN_MODELS {
            assert!(!desc.is_empty(), "empty description");
        }
    }

    #[test]
    fn context_window_default_is_200k_for_all_models() {
        // Without explicit 1M opt-in (context-1m beta), every model is 200k.
        assert_eq!(context_window_for_model("claude-opus-4-7"), 200_000);
        assert_eq!(context_window_for_model("claude-opus-4-6"), 200_000);
        assert_eq!(context_window_for_model("claude-sonnet-4-6"), 200_000);
        assert_eq!(context_window_for_model("claude-opus-4-5-20251101"), 200_000);
        assert_eq!(context_window_for_model("claude-haiku-4-5-20251001"), 200_000);
    }

    #[test]
    fn model_supports_1m_for_opus_46_and_sonnet_4() {
        assert!(model_supports_1m("claude-opus-4-6"));
        assert!(model_supports_1m("claude-opus-4-7"));
        assert!(model_supports_1m("claude-sonnet-4-6"));
        assert!(model_supports_1m("claude-sonnet-4-5-20250929"));
    }

    #[test]
    fn model_supports_1m_rejects_older_and_haiku() {
        assert!(!model_supports_1m("claude-opus-4-5"));
        assert!(!model_supports_1m("claude-haiku-4-5-20251001"));
        assert!(!model_supports_1m("claude-opus-3-5"));
    }

    #[test]
    fn model_supports_1m_assumed_for_5x() {
        assert!(model_supports_1m("claude-opus-5-0"));
        assert!(model_supports_1m("claude-sonnet-5-1"));
    }

    #[test]
    fn model_supports_1m_case_insensitive() {
        assert!(model_supports_1m("CLAUDE-OPUS-4-6"));
    }

    #[test]
    fn context_window_haiku_is_200k() {
        assert_eq!(context_window_for_model("claude-haiku-4-5-20251001"), 200_000);
    }

    #[test]
    fn context_window_opus3_is_200k() {
        assert_eq!(context_window_for_model("claude-opus-3-5-20250101"), 200_000);
    }

    #[test]
    fn context_window_unknown_defaults_200k() {
        assert_eq!(context_window_for_model("some-future-model"), 200_000);
        assert_eq!(context_window_for_model(""), 200_000);
    }

    #[test]
    fn adaptive_thinking_required_for_opus_4_7_plus() {
        assert!(model_supports_adaptive_thinking("claude-opus-4-7"));
        assert!(model_supports_adaptive_thinking("claude-opus-4-8"));
    }

    #[test]
    fn adaptive_thinking_not_for_opus_4_6() {
        // 4.6 uses enabled+budget_tokens (deprecated but functional)
        assert!(!model_supports_adaptive_thinking("claude-opus-4-6"));
    }

    #[test]
    fn adaptive_thinking_not_for_sonnet_4_6() {
        assert!(!model_supports_adaptive_thinking("claude-sonnet-4-6"));
    }

    #[test]
    fn adaptive_thinking_required_for_sonnet_4_7_plus() {
        assert!(model_supports_adaptive_thinking("claude-sonnet-4-7"));
    }

    #[test]
    fn adaptive_thinking_not_for_older_models() {
        assert!(!model_supports_adaptive_thinking("claude-opus-4-5"));
        assert!(!model_supports_adaptive_thinking("claude-sonnet-4-5"));
        assert!(!model_supports_adaptive_thinking("claude-haiku-4-5-20251001"));
        assert!(!model_supports_adaptive_thinking("claude-opus-3-5"));
    }

    #[test]
    fn adaptive_thinking_assumed_for_5x() {
        assert!(model_supports_adaptive_thinking("claude-opus-5-0"));
        assert!(model_supports_adaptive_thinking("claude-sonnet-5-1"));
    }

    #[test]
    fn adaptive_thinking_case_insensitive() {
        assert!(model_supports_adaptive_thinking("CLAUDE-OPUS-4-7"));
    }
}
