feat(db): add usage tracking schema and types

Add database tables for proxy request logs and model pricing.
Extend Provider and error types to support usage statistics.

src-tauri/src/commands/usage.rs

@@ -0,0 +1,152 @@
+//! 使用统计相关命令
+
+use crate::database::Database;
+use crate::error::AppError;
+use crate::services::usage_stats::*;
+use tauri::State;
+
+/// 获取使用量汇总
+#[tauri::command]
+pub fn get_usage_summary(
+    db: State<'_, Database>,
+    start_date: Option<i64>,
+    end_date: Option<i64>,
+) -> Result<UsageSummary, AppError> {
+    db.get_usage_summary(start_date, end_date)
+}
+
+/// 获取每日趋势
+#[tauri::command]
+pub fn get_usage_trends(
+    db: State<'_, Database>,
+    days: u32,
+) -> Result<Vec<DailyStats>, AppError> {
+    db.get_daily_trends(days)
+}
+
+/// 获取 Provider 统计
+#[tauri::command]
+pub fn get_provider_stats(db: State<'_, Database>) -> Result<Vec<ProviderStats>, AppError> {
+    db.get_provider_stats()
+}
+
+/// 获取模型统计
+#[tauri::command]
+pub fn get_model_stats(db: State<'_, Database>) -> Result<Vec<ModelStats>, AppError> {
+    db.get_model_stats()
+}
+
+/// 获取请求日志列表
+#[tauri::command]
+pub fn get_request_logs(
+    db: State<'_, Database>,
+    provider_id: Option<String>,
+    model: Option<String>,
+    status_code: Option<u16>,
+    start_date: Option<i64>,
+    end_date: Option<i64>,
+    limit: u32,
+    offset: u32,
+) -> Result<Vec<RequestLogDetail>, AppError> {
+    let filters = LogFilters {
+        provider_id,
+        model,
+        status_code,
+        start_date,
+        end_date,
+    };
+    db.get_request_logs(&filters, limit, offset)
+}
+
+/// 获取单个请求详情
+#[tauri::command]
+pub fn get_request_detail(
+    db: State<'_, Database>,
+    request_id: String,
+) -> Result<Option<RequestLogDetail>, AppError> {
+    db.get_request_detail(&request_id)
+}
+
+/// 获取模型定价列表
+#[tauri::command]
+pub fn get_model_pricing(db: State<'_, Database>) -> Result<Vec<ModelPricingInfo>, AppError> {
+    let conn = crate::database::lock_conn!(db.conn);
+    
+    let mut stmt = conn.prepare(
+        "SELECT model_id, display_name, input_cost_per_million, output_cost_per_million,
+                cache_read_cost_per_million, cache_creation_cost_per_million
+         FROM model_pricing
+         ORDER BY display_name"
+    )?;
+
+    let rows = stmt.query_map([], |row| {
+        Ok(ModelPricingInfo {
+            model_id: row.get(0)?,
+            display_name: row.get(1)?,
+            input_cost_per_million: row.get(2)?,
+            output_cost_per_million: row.get(3)?,
+            cache_read_cost_per_million: row.get(4)?,
+            cache_creation_cost_per_million: row.get(5)?,
+        })
+    })?;
+
+    let mut pricing = Vec::new();
+    for row in rows {
+        pricing.push(row?);
+    }
+
+    Ok(pricing)
+}
+
+/// 更新模型定价
+#[tauri::command]
+pub fn update_model_pricing(
+    db: State<'_, Database>,
+    model_id: String,
+    display_name: String,
+    input_cost: String,
+    output_cost: String,
+    cache_read_cost: String,
+    cache_creation_cost: String,
+) -> Result<(), AppError> {
+    let conn = crate::database::lock_conn!(db.conn);
+
+    conn.execute(
+        "INSERT OR REPLACE INTO model_pricing (
+            model_id, display_name, input_cost_per_million, output_cost_per_million,
+            cache_read_cost_per_million, cache_creation_cost_per_million
+        ) VALUES (?1, ?2, ?3, ?4, ?5, ?6)",
+        rusqlite::params![
+            model_id,
+            display_name,
+            input_cost,
+            output_cost,
+            cache_read_cost,
+            cache_creation_cost
+        ],
+    )
+    .map_err(|e| AppError::Database(format!("更新模型定价失败: {e}")))?;
+
+    Ok(())
+}
+
+/// 检查 Provider 使用限额
+#[tauri::command]
+pub fn check_provider_limits(
+    db: State<'_, Database>,
+    provider_id: String,
+    app_type: String,
+) -> Result<crate::services::usage_stats::ProviderLimitStatus, AppError> {
+    db.check_provider_limits(&provider_id, &app_type)
+}
+
+/// 模型定价信息
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
+pub struct ModelPricingInfo {
+    pub model_id: String,
+    pub display_name: String,
+    pub input_cost_per_million: String,
+    pub output_cost_per_million: String,
+    pub cache_read_cost_per_million: String,
+    pub cache_creation_cost_per_million: String,
+}