#!/bin/bash

# ===========================================
# 学生换班级处理脚本
# 处理类型: CLASS_CHANGE(换班级)
# ===========================================

set -euo pipefail

# Load configuration
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
CONFIG_FILE="${SCRIPT_DIR}/data.conf"

if [[ ! -f "$CONFIG_FILE" ]]; then
    echo "错误：配置文件 $CONFIG_FILE 未找到！"
    exit 1
fi

source "$CONFIG_FILE"

# Create log directory
mkdir -p "$LOG_DIR"

# Log file
LOG_FILE="${LOG_DIR}/process_student_class_change_$(date +%Y%m%d_%H%M%S).log"

# Lock file to prevent multiple instances
LOCK_FILE="${SCRIPT_DIR}/process_student_class_change.lock"

# Functions
log() {
    local level="$1"
    local message="$2"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')
    echo "[$timestamp] [$level] $message" | tee -a "$LOG_FILE"
}

error_exit() {
    local message="$1"
    log "ERROR" "$message"
    # Remove lock file
    [[ -f "$LOCK_FILE" ]] && rm -f "$LOCK_FILE"
    exit 1
}

# 检查脚本是否已在运行
if [[ -f "$LOCK_FILE" ]]; then
    if kill -0 $(cat "$LOCK_FILE") 2>/dev/null; then
        log "INFO" "脚本已在运行 (PID: $(cat "$LOCK_FILE"))"
        exit 1
    else
        log "WARN" "删除过期的锁定文件"
        rm -f "$LOCK_FILE"
    fi
fi

# Create lock file
echo $$ > "$LOCK_FILE"

# 清理函数
cleanup() {
    [[ -f "$LOCK_FILE" ]] && rm -f "$LOCK_FILE"
    log "INFO" "脚本执行完成"
}

trap cleanup EXIT

# Database functions
execute_sql() {
    local sql="$1"
    local result

    result=$(mysql -h"$DB_HOST" -P"$DB_PORT" -u"$DB_USER" -p"$DB_PASS" "$DB_NAME" -e "$sql" 2>&1)
    local exit_code=$?

    if [[ $exit_code -ne 0 ]]; then
        log "ERROR" "SQL执行失败: $sql"
        log "ERROR" "MySQL错误: $result"
        return 1
    fi

    echo "$result"
}

# Process student class change
process_student_class_change() {
    local record_id="$1"
    local student_id="$2"
    local student_no="$3"
    local new_class_id="$4"
    local operator_id="${5:-1}"

    log "INFO" "Processing student class change - ID: $record_id, Student: $student_no ($student_id), New Class ID: $new_class_id"

    # Get new class information
    local class_info_sql="
    SELECT
        c.college_id, c.college_name, c.major_id, c.major_name,
        c.class_code, c.class_name, c.class_type, c.grade,
        c.training_type, c.counselor_id, c.counselor_name,
        c.class_teacher_id, c.class_teacher_name, c.school_system
    FROM xg_class_msg c
    WHERE c.id = $new_class_id AND c.deleted = 0
    "

    local class_info
    class_info=$(execute_sql "$class_info_sql")

    if [[ -z "$class_info" || "$class_info" == *"Empty set"* ]]; then
        log "ERROR" "获取班级ID为 $new_class_id 的班级信息失败"
        return 1
    fi

    # Parse class information (skip header and separator lines, get data row)
    local class_data
    class_data=$(echo "$class_info" | grep -E '^[0-9]' | head -1)

    if [[ -z "$class_data" ]]; then
        log "ERROR" "解析班级信息失败，无法获取数据行"
        return 1
    fi

    # Use cut to extract specific fields reliably
    local college_id=$(echo "$class_data" | cut -f1)
    local college_name=$(echo "$class_data" | cut -f2)
    local major_id=$(echo "$class_data" | cut -f3)
    local major_name=$(echo "$class_data" | cut -f4)
    local class_code=$(echo "$class_data" | cut -f5)
    local class_name=$(echo "$class_data" | cut -f6)
    local class_type=$(echo "$class_data" | cut -f7)
    local grade=$(echo "$class_data" | cut -f8)
    local training_type=$(echo "$class_data" | cut -f9)
    local counselor_id=$(echo "$class_data" | cut -f10)
    local counselor_name=$(echo "$class_data" | cut -f11)
    local class_teacher_id=$(echo "$class_data" | cut -f12)
    local class_teacher_name=$(echo "$class_data" | cut -f13)
    local school_system=$(echo "$class_data" | cut -f14)

    # Handle NULL values for IDs
    local counselor_id_value class_teacher_id_value
    if [[ "$counselor_id" == "NULL" || -z "$counselor_id" ]]; then
        counselor_id_value="NULL"
    else
        counselor_id_value="'$counselor_id'"
    fi

    if [[ "$class_teacher_id" == "NULL" || -z "$class_teacher_id" ]]; then
        class_teacher_id_value="NULL"
    else
        class_teacher_id_value="'$class_teacher_id'"
    fi

    # Start transaction
    local transaction_sql="
    START TRANSACTION;

    -- 1. Backup original data to his tables (ignore if already exists)
    INSERT IGNORE INTO xg_student_msg_his SELECT * FROM xg_student_msg WHERE id = $student_id;
    INSERT IGNORE INTO xg_class_pos_msg_his SELECT * FROM xg_class_pos_msg WHERE student_id = $student_id;

    -- 2. Terminate cadre positions (干部信息终止)
    UPDATE xg_class_pos_msg SET
        is_current = 0,
        cadre_status = '4',  -- 免职
        dismissal_date = CURDATE(),
        dismissal_reason = '学生换班级',
        term_end_date = CURDATE(),
        term_duration = TIMESTAMPDIFF(MONTH, term_start_date, CURDATE()),
        update_by = $operator_id,
        update_time = NOW()
    WHERE student_id = $student_id AND is_current = 1;

    -- 3. Update student information with new class data
    UPDATE xg_student_msg SET
        -- 基础班级信息
        college_id = '$college_id',
        college_name = '$college_name',
        major_id = '$major_id',
        major_name = '$major_name',
        class_id = '$new_class_id',
        class_name = '$class_name',
        grade = '$grade',

        -- 预留字段从班级表关联获取的数据 (7182-7195行)
        school_system = '$school_system',
        academic_level = '$class_type',  -- class_type 对应 academic_level
        training_type = '$training_type',
        counselor_id = $counselor_id_value,
        counselor_name = '$counselor_name',
        class_teacher_id = $class_teacher_id_value,
        class_teacher_name = '$class_teacher_name',

        -- 更新信息
        update_by = $operator_id,
        update_time = NOW()
    WHERE id = $student_id;

    -- 4. Update class change record status
    UPDATE xg_student_class_change SET
        status = '1',  -- 已处理
        update_by = $operator_id,
        update_time = NOW()
    WHERE id = $record_id;

    COMMIT;
    "

    # 执行事务
    if execute_sql "$transaction_sql"; then
        log "INFO" "成功处理学生换班级 - ID: $record_id, 学生: $student_no"
        return 0
    else
        log "ERROR" "处理学生换班级失败 - ID: $record_id, 学生: $student_no"
        return 1
    fi
}

# Main function
main() {
    log "INFO" "启动学生换班级处理守护进程"
    log "INFO" "处理类型: CLASS_CHANGE(换班级)"
    log "INFO" "以连续模式运行，间隔10分钟"

    # 测试数据库连接
    log "INFO" "正在测试数据库连接..."
    if ! execute_sql "SELECT 1;" >/dev/null 2>&1; then
        error_exit "数据库连接失败"
    fi
    log "INFO" "数据库连接成功"

    # Main processing loop
    while true; do
        log "INFO" "开始新的处理周期"

        # 获取未处理的记录
        local query_sql="
        SELECT id, student_id, student_no, new_class_id, update_by
        FROM xg_student_class_change
        WHERE status = '0'
          AND deleted = 0
          AND effective_time <= NOW()
        ORDER BY create_time ASC
        LIMIT $BATCH_SIZE;
        "

        local records
        records=$(execute_sql "$query_sql")

        # 检查是否有记录需要处理
        # 过滤掉MySQL的边框和表头，只保留数据行
        local data_records
        data_records=$(echo "$records" | grep -E '^[0-9]' || true)

        if [[ -z "$data_records" ]]; then
            log "INFO" "未找到未处理的记录，正在等待..."
        else
            log "INFO" "找到待处理记录，开始处理..."
            records="$data_records"

            local processed_count=0
            local failed_count=0

            # Process each record
            while IFS=$'\t' read -r record_id student_id student_no new_class_id operator_id; do
                # Skip empty lines
                [[ -z "$record_id" ]] && continue

                local retry_count=0
                local success=false

                while [[ $retry_count -lt $MAX_RETRY && $success == false ]]; do
                    if process_student_class_change "$record_id" "$student_id" "$student_no" "$new_class_id" "$operator_id"; then
                        success=true
                        ((processed_count++))
                    else
                        ((retry_count++))
                        if [[ $retry_count -lt $MAX_RETRY ]]; then
                            log "WARN" "处理失败，$RETRY_DELAY 秒后重试... (尝试 $retry_count/$MAX_RETRY)"
                            sleep $RETRY_DELAY
                        fi
                    fi
                done

                if [[ $success == false ]]; then
                    ((failed_count++))
                    log "ERROR" "$MAX_RETRY 次尝试后仍处理失败 - ID: $record_id"
                fi

            done <<< "$records"

            log "INFO" "处理周期完成 - 已处理: $processed_count, 失败: $failed_count"
        fi

        # 等待配置的间隔时间后开始下一个周期
        log "INFO" "等待 $CYCLE_INTERVAL 秒后开始下一个处理周期..."
        sleep $CYCLE_INTERVAL
    done
}

# Run main function
main "$@"