// @ts-nocheck


const DEFAULT_THRESHOLD = 24000;
const DEFAULT_KEEP_RECENT = 6;
const TOOL_CONTENT_SOFT = 1800;
const TOOL_CONTENT_HARD = 800;

export function estimateTokens(messages, toolsCount = 0) {
    let chars = 0;
    for (const m of messages) {
        if (typeof m.content === 'string') {
            chars += m.content.length;
        }
        if (m.toolCalls) {
            for (const tc of m.toolCalls) {
                chars += JSON.stringify(tc).length;
            }
        }
        chars += (m.role || '').length + 10;
    }
    chars += toolsCount * 2100;
    return Math.ceil(chars / 3.5);
}

export function compressIfNeeded(messages, opts = {}) {
    const threshold = opts.threshold || DEFAULT_THRESHOLD;
    const keepRecent = opts.keepRecent || DEFAULT_KEEP_RECENT;
    const toolsCount = opts.toolsCount || 0;

    const originalTokens = estimateTokens(messages, toolsCount);

    if (originalTokens <= threshold) {
        return {
            messages,
            compressed: false,
            originalTokens,
            finalTokens: originalTokens,
            hiddenCount: 0,
        };
    }

    
    let working = slimToolMessages(messages, TOOL_CONTENT_SOFT);
    let tokens = estimateTokens(working, toolsCount);
    if (tokens <= threshold) {
        return {
            messages: working,
            compressed: true,
            originalTokens,
            finalTokens: tokens,
            hiddenCount: 0,
        };
    }

    
    working = slimToolMessages(messages, TOOL_CONTENT_HARD);
    tokens = estimateTokens(working, toolsCount);
    if (tokens <= threshold) {
        return {
            messages: working,
            compressed: true,
            originalTokens,
            finalTokens: tokens,
            hiddenCount: 0,
        };
    }

    
    const keepStart = findSafeKeepStart(working, keepRecent);
    const last = working.slice(keepStart);
    const lastUserIdx = (() => {
        for (let i = working.length - 1; i >= 0; i--) {
            if (working[i].role === 'user') return i;
        }
        return -1;
    })();

    const compressed = [];
    if (lastUserIdx >= 0 && lastUserIdx < keepStart) {
        compressed.push(working[lastUserIdx]);
    }

    const middleCount = lastUserIdx >= 0 && lastUserIdx < keepStart
        ? Math.max(0, keepStart - lastUserIdx - 1)
        : Math.max(0, keepStart);

    if (middleCount > 0) {
        compressed.push({
            role: 'system',
            content: `[上下文已压缩] 已隐藏中间 ${middleCount} 条历史消息,只保留完整的最近工具调用组。请根据仍保留的工具结果回答用户;若信息不足请如实说明。`,
            _compressed: true,
        });
    }

    compressed.push(...last);

    const finalTokens = estimateTokens(compressed, toolsCount);

    return {
        messages: compressed,
        compressed: true,
        originalTokens,
        finalTokens,
        hiddenCount: middleCount,
    };
}

function findSafeKeepStart(messages, minKeep) {
    if (!messages.length) return 0;
    let start = Math.max(0, messages.length - minKeep);

    
    while (start > 0 && messages[start].role === 'tool') {
        start--;
    }
    
    
    if (messages[start]?.role === 'tool') {
        while (start > 0 && messages[start].role === 'tool') start--;
    }

    
    

    
    

    
    return start;
}

function slimToolMessages(messages, maxLen) {
    return messages.map(m => {
        if (m.role !== 'tool') return m;
        const content = typeof m.content === 'string' ? m.content : JSON.stringify(m.content ?? '');
        if (content.length <= maxLen) return m;
        return {
            ...m,
            content: slimToolContent(content, maxLen),
        };
    });
}

function slimToolContent(content, maxLen) {
    try {
        const parsed = JSON.parse(content);
        const slim = slimToolObject(parsed);
        const out = JSON.stringify(slim);
        if (out.length <= maxLen) return out;
        return out.slice(0, maxLen) + '…[已截断]';
    } catch (_) {
        return content.slice(0, maxLen) + '…[已截断]';
    }
}

function slimToolObject(obj) {
    if (!obj || typeof obj !== 'object') return obj;
    if (Array.isArray(obj)) {
        return obj.length > 3
            ? [...obj.slice(0, 3), `…另有 ${obj.length - 3} 条已省略`]
            : obj;
    }

    const out = {};
    for (const [k, v] of Object.entries(obj)) {
        
        if (k === '_call' || k === 'guidance' || k === 'assistantGuidance' || k === 'ok' || k === 'error') {
            out[k] = v;
            continue;
        }
        if (k === 'result' && v && typeof v === 'object') {
            out[k] = slimToolObject(v);
            continue;
        }
        if (k === 'overview' || k === 'summary' || k === 'currentEntity' || k === 'lastQueryType') {
            out[k] = typeof v === 'object' ? slimToolObject(v) : v;
            continue;
        }
        if (Array.isArray(v)) {
            if (v.length === 0) {
                out[k] = v;
            } else if (typeof v[0] !== 'object') {
                out[k] = v.length > 8 ? [...v.slice(0, 8), `…+${v.length - 8}`] : v;
            } else {
                out[k] = {
                    _omitted: true,
                    count: v.length,
                    sample: slimToolObject(v[0]),
                };
            }
            continue;
        }
        if (v && typeof v === 'object') {
            out[k] = slimToolObject(v);
            continue;
        }
        out[k] = v;
    }
    return out;
}