#!/usr/bin/env node
// gsd-hook-version: 1.30.0
// Claude Code Statusline - GSD Edition
// Shows: model | current task | directory | context usage
//
// SHARED CANONICAL FILE - hardlinked into all harness hooks/ directories.
// Harness config dir is auto-detected from __dirname at runtime.
// Do NOT hardcode harness-specific paths here.

const fs = require('fs');
const path = require('path');
const os = require('os');

// Read JSON from stdin
let input = '';
// Timeout guard: if stdin doesn't close within 3s (e.g. pipe issues on
// Windows/Git Bash), exit silently instead of hanging. See #775.
const stdinTimeout = setTimeout(() => process.exit(0), 3000);
process.stdin.setEncoding('utf8');
process.stdin.on('data', chunk => input += chunk);
process.stdin.on('end', () => {
    clearTimeout(stdinTimeout);
    try {
        const data = JSON.parse(input);
        const model = data.model?.display_name || 'Claude';
        const dir = data.workspace?.current_dir || process.cwd();
        const session = data.session_id || '';
        const remaining = data.context_window?.remaining_percentage;

        // Context window display (shows USED percentage scaled to usable context)
        // Claude Code reserves ~16.5% for autocompact buffer, so usable context
        // is 83.5% of the total window. We normalize to show 100% at that point.
        const AUTO_COMPACT_BUFFER_PCT = 16.5;
        let ctx = '';
        if (remaining != null) {
            // Normalize: subtract buffer from remaining, scale to usable range
            const usableRemaining = Math.max(0, ((remaining - AUTO_COMPACT_BUFFER_PCT) / (100 - AUTO_COMPACT_BUFFER_PCT)) * 100);
            const used = Math.max(0, Math.min(100, Math.round(100 - usableRemaining)));

            // Write context metrics to bridge file for the context-monitor PostToolUse hook.
            // The monitor reads this file to inject agent-facing warnings when context is low.
            if (session) {
                try {
                    const bridgePath = path.join(os.tmpdir(), `claude-ctx-${session}.json`);
                    const bridgeData = JSON.stringify({
                        session_id: session,
                        remaining_percentage: remaining,
                        used_pct: used,
                        timestamp: Math.floor(Date.now() / 1000)
                    });
                    fs.writeFileSync(bridgePath, bridgeData);
                } catch (e) {
                    // Silent fail -- bridge is best-effort, don't break statusline
                }
            }

            // Build progress bar (10 segments)
            const filled = Math.floor(used / 10);
            const bar = '█'.repeat(filled) + '░'.repeat(10 - filled);

            // Color based on usable context thresholds
            if (used < 50) {
                ctx = ` \x1b[32m${bar} ${used}%\x1b[0m`;
            } else if (used < 65) {
                ctx = ` \x1b[33m${bar} ${used}%\x1b[0m`;
            } else if (used < 80) {
                ctx = ` \x1b[38;5;208m${bar} ${used}%\x1b[0m`;
            } else {
                ctx = ` \x1b[5;31m💀 ${bar} ${used}%\x1b[0m`;
            }
        }

        // Current task from todos
        let task = '';
        const homeDir = os.homedir();
        // Derive harness config dir from this file's location at runtime.
        // e.g. /home/user/.claude/hooks/gsd-statusline.js -> /home/user/.claude
        // Respects CLAUDE_CONFIG_DIR for custom config directory setups (#870)
        const harnessDir = path.basename(path.dirname(path.dirname(__filename)));
        const claudeDir = process.env.CLAUDE_CONFIG_DIR || path.join(homeDir, harnessDir);
        const todosDir = path.join(claudeDir, 'todos');
        if (session && fs.existsSync(todosDir)) {
            try {
                const files = fs.readdirSync(todosDir)
                    .filter(f => f.startsWith(session) && f.includes('-agent-') && f.endsWith('.json'))
                    .map(f => ({ name: f, mtime: fs.statSync(path.join(todosDir, f)).mtime }))
                    .sort((a, b) => b.mtime - a.mtime);

                if (files.length > 0) {
                    try {
                        const todos = JSON.parse(fs.readFileSync(path.join(todosDir, files[0].name), 'utf8'));
                        const inProgress = todos.find(t => t.status === 'in_progress');
                        if (inProgress) task = inProgress.activeForm || '';
                    } catch (e) { }
                }
            } catch (e) {
                // Silently fail on file system errors - don't break statusline
            }
        }

        // GSD update available?
        let gsdUpdate = '';
        const cacheFile = path.join(claudeDir, 'cache', 'gsd-update-check.json');
        if (fs.existsSync(cacheFile)) {
            try {
                const cache = JSON.parse(fs.readFileSync(cacheFile, 'utf8'));
                if (cache.update_available) {
                    gsdUpdate = '\x1b[33m⬆ /gsd-update\x1b[0m │ ';
                }
                if (cache.stale_hooks && cache.stale_hooks.length > 0) {
                    gsdUpdate += '\x1b[31m⚠ stale hooks - run /gsd-update\x1b[0m │ ';
                }
            } catch (e) { }
        }

        // Output
        const dirname = path.basename(dir);
        if (task) {
            process.stdout.write(`${gsdUpdate}\x1b[2m${model}\x1b[0m │ \x1b[1m${task}\x1b[0m │ \x1b[2m${dirname}\x1b[0m${ctx}`);
        } else {
            process.stdout.write(`${gsdUpdate}\x1b[2m${model}\x1b[0m │ \x1b[2m${dirname}\x1b[0m${ctx}`);
        }
    } catch (e) {
        // Silent fail - don't break statusline on parse errors
    }
});