/**
 * OpenAI reasoning_effort to Cloud Code thinking configuration.
 * Ported from llm-proxy-rotate AntigravityProvider._get_thinking_config().
 */

export const VALID_REASONING_EFFORTS = new Set([
    'auto',
    'disable',
    'off',
    'none',
    'minimal',
    'low',
    'low_medium',
    'medium',
    'medium_high',
    'high'
]);

export function normalizeReasoningEffort(value) {
    if (value === undefined || value === null) return 'auto';
    if (typeof value !== 'string') return 'auto';

    const normalized = value.trim().toLowerCase() || 'auto';
    return VALID_REASONING_EFFORTS.has(normalized) ? normalized : 'auto';
}

/** Pro tier is encoded in SKU names like gemini-3.1-pro-high / gemini-3.1-pro-low. */
export function isGeminiProTierSku(modelName) {
    return /gemini-3(?:\.\d+)?-pro-(?:high|low)$/i.test(String(modelName || ''));
}

export function getReasoningThinkingConfig(modelName, reasoningEffort) {
    const model = String(modelName || '').toLowerCase();
    const effort = normalizeReasoningEffort(reasoningEffort);

    // Tier SKUs already encode thinking level; extra thinkingConfig causes INVALID_ARGUMENT.
    if (isGeminiProTierSku(model)) {
        return null;
    }

    const isGemini3Flash = /gemini-3(?:\.\d+)?-[^/]*flash/.test(model);
    const isGemini3Pro = /gemini-3(?:\.\d+)?-[^/]*pro/.test(model);
    const isGemini25 = model.includes('gemini-2.5');
    const isClaude = model.includes('claude');

    if (!isGemini3Flash && !isGemini3Pro && !isGemini25 && !isClaude) {
        return null;
    }

    if (isGemini3Flash) {
        let thinkingLevel = 'high';
        if (['disable', 'off', 'none'].includes(effort)) {
            thinkingLevel = 'minimal';
        } else if (['minimal', 'low'].includes(effort)) {
            thinkingLevel = 'low';
        } else if (['low_medium', 'medium'].includes(effort)) {
            thinkingLevel = 'medium';
        }

        return {
            effort,
            mode: 'level',
            config: {
                includeThoughts: true,
                thinkingLevel
            }
        };
    }

    if (isGemini3Pro) {
        const thinkingLevel = [
            'disable', 'off', 'none', 'minimal', 'low', 'low_medium'
        ].includes(effort) ? 'low' : 'high';

        return {
            effort,
            mode: 'level',
            config: {
                includeThoughts: true,
                thinkingLevel
            }
        };
    }

    if (['disable', 'off', 'none'].includes(effort)) {
        return {
            effort,
            mode: 'budget',
            config: isClaude
                ? { include_thoughts: false, thinking_budget: 0 }
                : { includeThoughts: false, thinkingBudget: 0 }
        };
    }

    if (effort === 'auto') {
        return {
            effort,
            mode: 'budget',
            config: isClaude
                ? { include_thoughts: true, thinking_budget: -1 }
                : { includeThoughts: true, thinkingBudget: -1 }
        };
    }

    const budgets = model.includes('gemini-2.5-flash')
        ? {
            minimal: 3072,
            low: 6144,
            low_medium: 9216,
            medium: 12288,
            medium_high: 18432,
            high: 24576
        }
        : {
            minimal: 4096,
            low: 8192,
            low_medium: 12288,
            medium: 16384,
            medium_high: 24576,
            high: isClaude ? 31999 : 32768
        };

    return {
        effort,
        mode: 'budget',
        config: isClaude
            ? { include_thoughts: true, thinking_budget: budgets[effort] }
            : { includeThoughts: true, thinkingBudget: budgets[effort] }
    };
}