/**
 * 投递记录控制器
 */

const db = require('../../config/database');

/**
 * 创建投递记录
 */
exports.createApplication = async (req, res) => {
    try {
        const userId = req.user.id;
        const {
            job_type, job_name, company_name, company_short_name,
            city, province, segment_name, application_data
        } = req.body;

        // 验证必填字段
        if (!job_type || !job_name || !company_name) {
            return res.status(400).json({
                success: false,
                message: '岗位类型、岗位名称和企业名称不能为空'
            });
        }

        // 验证job_type
        if (!['transition', 'referral'].includes(job_type)) {
            return res.status(400).json({
                success: false,
                message: '无效的岗位类型'
            });
        }

        // 检查是否已投递过相同岗位
        const [existing] = await db.query(`
            SELECT id FROM job_applications
            WHERE user_id = ? AND job_name = ? AND company_name = ? AND status != 'withdrawn'
        `, [userId, job_name, company_name]);

        if (existing.length > 0) {
            return res.status(400).json({
                success: false,
                message: '您已经投递过该岗位'
            });
        }

        // 插入投递记录
        const [result] = await db.query(`
            INSERT INTO job_applications (
                user_id, job_type, job_name, company_name, company_short_name,
                city, province, segment_name, status, application_data
            ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, 'pending', ?)
        `, [
            userId, job_type, job_name, company_name, company_short_name || null,
            city || null, province || null, segment_name || null,
            application_data ? JSON.stringify(application_data) : null
        ]);

        res.status(201).json({
            success: true,
            message: '投递成功',
            data: {
                id: result.insertId
            }
        });

    } catch (error) {
        console.error('创建投递记录错误:', error);
        res.status(500).json({
            success: false,
            message: '服务器错误'
        });
    }
};

/**
 * 获取投递记录列表
 */
exports.getApplications = async (req, res) => {
    try {
        const userId = req.user.id;
        const { job_type, status, page = 1, limit = 20 } = req.query;

        // 构建查询条件
        let whereClause = 'user_id = ?';
        const params = [userId];

        if (job_type) {
            whereClause += ' AND job_type = ?';
            params.push(job_type);
        }

        if (status) {
            whereClause += ' AND status = ?';
            params.push(status);
        }

        // 计算分页
        const offset = (page - 1) * limit;

        // 查询总数
        const [countResult] = await db.query(
            `SELECT COUNT(*) as total FROM job_applications WHERE ${whereClause}`,
            params
        );
        const total = countResult[0].total;

        // 查询列表
        const [applications] = await db.query(`
            SELECT
                id, job_type, job_name, company_name, company_short_name,
                city, province, segment_name, status, applied_at, updated_at, notes
            FROM job_applications
            WHERE ${whereClause}
            ORDER BY applied_at DESC
            LIMIT ? OFFSET ?
        `, [...params, parseInt(limit), parseInt(offset)]);

        res.json({
            success: true,
            data: {
                list: applications,
                pagination: {
                    page: parseInt(page),
                    limit: parseInt(limit),
                    total,
                    totalPages: Math.ceil(total / limit)
                }
            }
        });

    } catch (error) {
        console.error('获取投递记录错误:', error);
        res.status(500).json({
            success: false,
            message: '服务器错误'
        });
    }
};

/**
 * 获取单个投递记录详情
 */
exports.getApplicationDetail = async (req, res) => {
    try {
        const userId = req.user.id;
        const { id } = req.params;

        const [applications] = await db.query(`
            SELECT * FROM job_applications
            WHERE id = ? AND user_id = ?
        `, [id, userId]);

        if (applications.length === 0) {
            return res.status(404).json({
                success: false,
                message: '投递记录不存在'
            });
        }

        const application = applications[0];

        // 解析JSON字段
        if (application.application_data) {
            try {
                application.application_data = JSON.parse(application.application_data);
            } catch (e) {
                application.application_data = null;
            }
        }

        res.json({
            success: true,
            data: application
        });

    } catch (error) {
        console.error('获取投递详情错误:', error);
        res.status(500).json({
            success: false,
            message: '服务器错误'
        });
    }
};

/**
 * 撤回投递
 */
exports.withdrawApplication = async (req, res) => {
    try {
        const userId = req.user.id;
        const { id } = req.params;

        // 检查投递记录是否存在且属于当前用户
        const [applications] = await db.query(`
            SELECT id, status FROM job_applications
            WHERE id = ? AND user_id = ?
        `, [id, userId]);

        if (applications.length === 0) {
            return res.status(404).json({
                success: false,
                message: '投递记录不存在'
            });
        }

        const application = applications[0];

        // 检查状态是否允许撤回
        if (['offered', 'rejected', 'withdrawn'].includes(application.status)) {
            return res.status(400).json({
                success: false,
                message: '该投递记录无法撤回'
            });
        }

        // 更新状态为撤回
        await db.query(`
            UPDATE job_applications
            SET status = 'withdrawn', updated_at = NOW()
            WHERE id = ?
        `, [id]);

        res.json({
            success: true,
            message: '撤回成功'
        });

    } catch (error) {
        console.error('撤回投递错误:', error);
        res.status(500).json({
            success: false,
            message: '服务器错误'
        });
    }
};

/**
 * 获取投递统计
 */
exports.getStatistics = async (req, res) => {
    try {
        const userId = req.user.id;

        // 统计各状态的投递数量
        const [stats] = await db.query(`
            SELECT
                COUNT(*) as total,
                SUM(CASE WHEN job_type = 'transition' THEN 1 ELSE 0 END) as transition_count,
                SUM(CASE WHEN job_type = 'referral' THEN 1 ELSE 0 END) as referral_count,
                SUM(CASE WHEN status = 'pending' THEN 1 ELSE 0 END) as pending_count,
                SUM(CASE WHEN status = 'reviewing' THEN 1 ELSE 0 END) as reviewing_count,
                SUM(CASE WHEN status = 'interviewed' THEN 1 ELSE 0 END) as interviewed_count,
                SUM(CASE WHEN status = 'offered' THEN 1 ELSE 0 END) as offered_count,
                SUM(CASE WHEN status = 'rejected' THEN 1 ELSE 0 END) as rejected_count
            FROM job_applications
            WHERE user_id = ?
        `, [userId]);

        res.json({
            success: true,
            data: stats[0]
        });

    } catch (error) {
        console.error('获取统计错误:', error);
        res.status(500).json({
            success: false,
            message: '服务器错误'
        });
    }
};