// MCP tools: all 12 tools exposed to MCP clients.
//
// Food lookup:    search_food, get_food_by_barcode
// Logging:        log_food, log_custom_food, delete_entry
// Summary:        daily_summary, history, list_entries
// Goals:          get_goals, set_goals
// Weight:         log_weight, weight_history
// Future:         bulk_import (stub)

use std::sync::Arc;

use rmcp::{
    ErrorData as McpError, ServerHandler,
    handler::server::{
        router::tool::ToolRouter,
        wrapper::Parameters,
    },
    model::*,
    schemars,
    tool, tool_handler, tool_router,
};
use serde::Deserialize;
use serde_json::{json, Value};
use sqlx::Row;

use crate::api::{OffClient, Product};
use crate::config::Config;
use crate::db::{self, TRACKED_NUTRIENTS};

/// The MCP server handler. Each client session gets its own instance,
/// but they share the same Config (which contains the DB path — the pool
/// is created per-session to keep the struct Clone-able).
#[derive(Clone)]
pub struct NutritionServer {
    config: Arc<Config>,
    off_client: OffClient,
    tool_router: ToolRouter<NutritionServer>,
}

impl NutritionServer {
    pub fn new(config: Arc<Config>) -> Self {
        let off_client = OffClient::new(&config.off_user_agent);
        Self {
            config,
            off_client,
            tool_router: Self::tool_router(),
        }
    }

    /// Get a DB pool. Creates one on demand (cheap — SQLite is file-based).
    async fn pool(&self) -> Result<sqlx::SqlitePool, McpError> {
        db::init_database(&self.config.db_path)
            .await
            .map_err(|e| McpError::internal_error(format!("DB init failed: {e}"), None))
    }
}

// ── Tool parameter structs ──────────────────────────────────────────

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct SearchFoodParams {
    /// Food name to search for (e.g. "chicken breast", "coca cola")
    pub query: String,
    /// Number of results to return (default 10, max 50)
    #[serde(default)]
    pub page_size: Option<u32>,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct BarcodeParams {
    /// Product barcode (EAN-13, UPC, etc.)
    pub barcode: String,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct LogFoodParams {
    /// Product code (barcode) from OFF — use search_food or get_food_by_barcode first
    pub product_code: String,
    /// Amount in grams. If provided, takes precedence over servings.
    #[serde(default)]
    pub grams: Option<f64>,
    /// Number of servings. Uses OFF serving_quantity if available.
    #[serde(default)]
    pub servings: Option<f64>,
    /// Date in YYYY-MM-DD format. Defaults to today.
    #[serde(default)]
    pub date: Option<String>,
    /// Meal type: breakfast, lunch, dinner, snack. Auto-detected from time if omitted.
    #[serde(default)]
    pub meal: Option<String>,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct LogCustomFoodParams {
    /// Food name (e.g. "homemade salad", "restaurant pizza")
    pub name: String,
    /// Calories per 100g
    pub calories: f64,
    /// Nutrients per 100g as JSON object. Keys: protein, carbohydrates, fat, fiber, sugars,
    /// saturated_fat, salt, fructose, alcohol, potassium, calcium, magnesium, cholesterol.
    /// All values in grams or mg (matching OFF _100g units). Calories separate.
    #[serde(default)]
    pub nutriments: Option<Value>,
    /// Amount consumed in grams
    pub grams: f64,
    /// Date in YYYY-MM-DD format. Defaults to today.
    #[serde(default)]
    pub date: Option<String>,
    /// Meal type. Auto-detected from time if omitted.
    #[serde(default)]
    pub meal: Option<String>,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct DeleteEntryParams {
    /// Entry ID (from list_entries)
    pub id: i64,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct DateParams {
    /// Date in YYYY-MM-DD format. Defaults to today.
    #[serde(default)]
    pub date: Option<String>,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct HistoryParams {
    /// Number of days of history (default 7)
    #[serde(default)]
    pub days: Option<u32>,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct SetGoalsParams {
    /// JSON object with nutrient goals. Partial updates are merged with existing goals.
    /// Keys: energy_kcal, protein, carbohydrates, fat, fiber, sugars, saturated_fat,
    /// salt, fructose, alcohol, potassium, calcium, magnesium, cholesterol.
    pub goals: Value,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct LogWeightParams {
    /// Body weight in kilograms
    pub weight_kg: f64,
    /// Date in YYYY-MM-DD format. Defaults to today.
    #[serde(default)]
    pub date: Option<String>,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct WeightHistoryParams {
    /// Number of days of weight history (default 30)
    #[serde(default)]
    pub days: Option<u32>,
}

#[derive(Debug, Deserialize, schemars::JsonSchema)]
pub struct BulkImportParams {
    /// URL to a Parquet file (future: HuggingFace dataset). Not yet implemented.
    #[serde(default)]
    pub parquet_url: Option<String>,
}

// ── Helper functions ────────────────────────────────────────────────

fn today() -> String {
    chrono::Local::now().format("%Y-%m-%d").to_string()
}

fn detect_meal() -> String {
    let hour = chrono::Local::now().format("%H").to_string().parse::<u32>().unwrap_or(12);
    match hour {
        h if h < 11 => "breakfast".to_string(),
        h if h < 15 => "lunch".to_string(),
        h if h < 21 => "dinner".to_string(),
        _ => "snack".to_string(),
    }
}

/// Scale nutrient JSON from per-100g to actual portion.
/// multiplies each numeric value by (grams / 100).
fn scale_nutriments(nutriments: &Value, grams: f64) -> Value {
    let factor = grams / 100.0;
    if let Some(obj) = nutriments.as_object() {
        let scaled: serde_json::Map<String, Value> = obj
            .iter()
            .map(|(k, v)| {
                let scaled_v = if let Some(n) = v.as_f64() {
                    json!(n * factor)
                } else {
                    v.clone()
                };
                (k.clone(), scaled_v)
            })
            .collect();
        Value::Object(scaled)
    } else {
        nutriments.clone()
    }
}

/// Build a summary JSON from a list of entries' nutriments.
/// Sums all tracked nutrients, returns "no data" for missing ones.
fn sum_nutriments(entries_nutriments: &[Value]) -> Value {
    let mut totals: serde_json::Map<String, Value> = serde_json::Map::new();

    for (_, tracked_key) in TRACKED_NUTRIENTS {
        let mut sum = 0.0;
        let mut has_data = false;
        for entry_nutriments in entries_nutriments {
            if let Some(val) = entry_nutriments.get(tracked_key).and_then(|v| v.as_f64()) {
                sum += val;
                has_data = true;
            }
        }
        let display_key = tracked_key.replace("_100g", "");
        totals.insert(
            display_key,
            if has_data { json!(sum) } else { json!("no data") },
        );
    }

    Value::Object(totals)
}

/// Format a product for display in tool results.
fn product_to_json(p: &Product) -> Value {
    let nutriments: Value = serde_json::from_str(&p.nutriments).unwrap_or(json!({}));
    json!({
        "code": p.code,
        "product_name": p.product_name,
        "brands": p.brands,
        "nutriments_per_100g": nutriments,
        "serving_quantity": p.serving_quantity,
        "serving_size": p.serving_size,
        "image_url": p.image_url,
    })
}

fn ok(text: String) -> Result<CallToolResult, McpError> {
    Ok(CallToolResult::success(vec![Content::text(text)]))
}

// ── MCP tool implementations ────────────────────────────────────────

#[tool_router]
impl NutritionServer {
    // ── Food lookup ──────────────────────────────────────────────

    #[tool(
        description = "Search for food products by name using OpenFood Facts full-text search. \
                       Returns products with nutrition data per 100g. Results are cached locally. \
                       Use this when the user mentions a food item by name."
    )]
    async fn search_food(
        &self,
        Parameters(params): Parameters<SearchFoodParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;
        let page_size = params.page_size.unwrap_or(10).min(50);

        // Try cache first (FTS5)
        let cached = OffClient::cache_search(&pool, &params.query, page_size)
            .await
            .map_err(|e| McpError::internal_error(format!("Cache search failed: {e}"), None))?;

        let products = if !cached.is_empty() {
            tracing::debug!("Cache hit for '{}': {} results", params.query, cached.len());
            cached
        } else {
            tracing::debug!("Cache miss for '{}', querying OFF", params.query);
            let results = self
                .off_client
                .search(&params.query, page_size)
                .await
                .map_err(|e| McpError::internal_error(format!("OFF search failed: {e}"), None))?;

            // Cache the results
            let _ = OffClient::cache_products(&pool, &results).await;
            results
        };

        if products.is_empty() {
            return ok(format!("No products found for \"{}\"", params.query));
        }

        let results: Vec<Value> = products.iter().map(product_to_json).collect();
        ok(serde_json::to_string_pretty(&json!({
            "query": params.query,
            "count": results.len(),
            "products": results
        }))
        .unwrap_or_default())
    }

    #[tool(
        description = "Look up a food product by barcode (EAN-13, UPC) using OpenFood Facts API v3. \
                       Returns full nutrition data. Result is cached locally."
    )]
    async fn get_food_by_barcode(
        &self,
        Parameters(params): Parameters<BarcodeParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;

        // Check cache
        if let Some(cached) = OffClient::cache_get(&pool, &params.barcode)
            .await
            .map_err(|e| McpError::internal_error(format!("Cache lookup failed: {e}"), None))?
        {
            return ok(serde_json::to_string_pretty(&product_to_json(&cached)).unwrap_or_default());
        }

        // Query OFF API
        let product = self
            .off_client
            .get_by_barcode(&params.barcode)
            .await
            .map_err(|e| McpError::internal_error(format!("OFF API failed: {e}"), None))?;

        match product {
            Some(p) => {
                let _ = OffClient::cache_products(&pool, std::slice::from_ref(&p)).await;
                ok(serde_json::to_string_pretty(&product_to_json(&p)).unwrap_or_default())
            }
            None => ok(format!(
                "No product found for barcode {}",
                params.barcode
            )),
        }
    }

    // ── Logging ──────────────────────────────────────────────────

    #[tool(
        description = "Log a food item from OpenFood Facts by product code (barcode). \
                       Scales nutrients by portion (grams or servings). \
                       Shows daily summary after logging. \
                       Always search_food or get_food_by_barcode first to get the product_code."
    )]
    async fn log_food(
        &self,
        Parameters(params): Parameters<LogFoodParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;
        let date = params.date.unwrap_or_else(today);
        let meal = params.meal.unwrap_or_else(detect_meal);

        // Get product from cache or OFF
        let product = if let Some(p) = OffClient::cache_get(&pool, &params.product_code)
            .await
            .map_err(|e| McpError::internal_error(format!("Cache lookup failed: {e}"), None))?
        {
            p
        } else {
            self.off_client
                .get_by_barcode(&params.product_code)
                .await
                .map_err(|e| McpError::internal_error(format!("OFF API failed: {e}"), None))?
                .ok_or_else(|| {
                    McpError::invalid_params(
                        format!("Product not found: {}", params.product_code),
                        None,
                    )
                })?
        };

        // Calculate grams
        let grams = if let Some(g) = params.grams {
            g
        } else if let Some(s) = params.servings {
            s * product.serving_quantity.unwrap_or(100.0)
        } else {
            100.0 // default to 100g
        };

        // Scale nutriments
        let nutriments: Value = serde_json::from_str(&product.nutriments).unwrap_or(json!({}));
        let scaled = scale_nutriments(&nutriments, grams);

        // Insert entry
        let result = sqlx::query(
            r#"INSERT INTO entries (date, meal, product_code, food_name, grams, servings, nutriments)
               VALUES (?, ?, ?, ?, ?, ?, ?)"#,
        )
        .bind(&date)
        .bind(&meal)
        .bind(&params.product_code)
        .bind(&product.product_name)
        .bind(grams)
        .bind(params.servings)
        .bind(scaled.to_string())
        .execute(&pool)
        .await
        .map_err(|e| McpError::internal_error(format!("Insert failed: {e}"), None))?;

        let id = result.last_insert_rowid();

        // Get daily summary
        let summary = self.build_daily_summary(&pool, &date).await?;

        ok(format!(
            "✓ Logged: {} ({}g)\n  Entry ID: {}\n  Meal: {}\n  Date: {}\n\n{}",
            product.product_name, grams, id, meal, date, summary
        ))
    }

    #[tool(
        description = "Log a custom food item not in OpenFood Facts (homemade meals, restaurant food). \
                       Provide calories and nutrients per 100g, plus grams consumed."
    )]
    async fn log_custom_food(
        &self,
        Parameters(params): Parameters<LogCustomFoodParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;
        let date = params.date.unwrap_or_else(today);
        let meal = params.meal.unwrap_or_else(detect_meal);

        // Build nutriments JSON — include calories in the energy-kcal_100g field
        let mut nutriments = params.nutriments.unwrap_or(json!({}));
        if let Some(obj) = nutriments.as_object_mut() {
            obj.insert("energy-kcal_100g".to_string(), json!(params.calories));
        } else {
            nutriments = json!({"energy-kcal_100g": params.calories});
        }

        let scaled = scale_nutriments(&nutriments, params.grams);

        let result = sqlx::query(
            r#"INSERT INTO entries (date, meal, food_name, grams, nutriments)
               VALUES (?, ?, ?, ?, ?)"#,
        )
        .bind(&date)
        .bind(&meal)
        .bind(&params.name)
        .bind(params.grams)
        .bind(scaled.to_string())
        .execute(&pool)
        .await
        .map_err(|e| McpError::internal_error(format!("Insert failed: {e}"), None))?;

        let id = result.last_insert_rowid();
        let summary = self.build_daily_summary(&pool, &date).await?;

        ok(format!(
            "✓ Logged: {} ({}g, {} cal/100g)\n  Entry ID: {}\n  Meal: {}\n  Date: {}\n\n{}",
            params.name, params.grams, params.calories, id, meal, date, summary
        ))
    }

    #[tool(
        description = "Delete a food log entry by ID. Use list_entries to find the ID first."
    )]
    async fn delete_entry(
        &self,
        Parameters(params): Parameters<DeleteEntryParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;

        let result = sqlx::query("DELETE FROM entries WHERE id = ?")
            .bind(params.id)
            .execute(&pool)
            .await
            .map_err(|e| McpError::internal_error(format!("Delete failed: {e}"), None))?;

        if result.rows_affected() == 0 {
            return ok(format!("No entry found with ID {}", params.id));
        }

        ok(format!("✓ Deleted entry {}", params.id))
    }

    // ── Summary & History ────────────────────────────────────────

    #[tool(
        description = "Show daily nutrition summary for a date (default: today). \
                       Shows all 14 tracked nutrients vs goals, remaining calories/fructose/salt, \
                       and a list of all entries for the day."
    )]
    async fn daily_summary(
        &self,
        Parameters(params): Parameters<DateParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;
        let date = params.date.unwrap_or_else(today);
        let summary = self.build_daily_summary(&pool, &date).await?;
        ok(summary)
    }

    #[tool(
        description = "Show nutrition history for the last N days (default 7). \
                       Shows daily totals for key nutrients (calories, protein, fructose, salt, potassium)."
    )]
    async fn history(
        &self,
        Parameters(params): Parameters<HistoryParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;
        let days = params.days.unwrap_or(7);

        let rows = sqlx::query(
            r#"SELECT date, nutriments FROM entries
               WHERE date >= date('now', ?)
               ORDER BY date DESC"#,
        )
        .bind(format!("-{} days", days))
        .fetch_all(&pool)
        .await
        .map_err(|e| McpError::internal_error(format!("History query failed: {e}"), None))?;

        // Group by date
        let mut by_date: std::collections::BTreeMap<String, Vec<Value>> = std::collections::BTreeMap::new();
        for row in rows {
            let date: String = row.try_get("date").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let nutriments_str: String = row.try_get("nutriments").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let n: Value = serde_json::from_str(&nutriments_str).unwrap_or(json!({}));
            by_date.entry(date).or_default().push(n);
        }

        let mut days_summary = Vec::new();
        for (date, entries) in by_date.iter().rev() {
            let totals = sum_nutriments(entries);
            days_summary.push(json!({
                "date": date,
                "totals": totals,
                "entries": entries.len(),
            }));
        }

        ok(serde_json::to_string_pretty(&json!({
            "days": days,
            "history": days_summary
        }))
        .unwrap_or_default())
    }

    #[tool(
        description = "List all food log entries for a date (default: today). \
                       Shows entry IDs needed for delete_entry."
    )]
    async fn list_entries(
        &self,
        Parameters(params): Parameters<DateParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;
        let date = params.date.unwrap_or_else(today);

        let rows = sqlx::query(
            r#"SELECT id, meal, food_name, grams, nutriments, created_at
               FROM entries WHERE date = ? ORDER BY created_at"#,
        )
        .bind(&date)
        .fetch_all(&pool)
        .await
        .map_err(|e| McpError::internal_error(format!("List query failed: {e}"), None))?;

        if rows.is_empty() {
            return ok(format!("No entries for {}", date));
        }

        let mut entries = Vec::new();
        for row in rows {
            let id: i64 = row.try_get("id").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let meal: String = row.try_get("meal").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let food_name: String = row.try_get("food_name").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let grams: Option<f64> = row.try_get::<Option<f64>, _>("grams").ok().flatten();
            let created_at: String = row.try_get("created_at").map_err(|e| McpError::internal_error(e.to_string(), None))?;

            entries.push(json!({
                "id": id,
                "meal": meal,
                "food_name": food_name,
                "grams": grams,
                "time": created_at,
            }));
        }

        ok(serde_json::to_string_pretty(&json!({
            "date": date,
            "entries": entries
        }))
        .unwrap_or_default())
    }

    // ── Goals ────────────────────────────────────────────────────

    #[tool(
        description = "Get current daily nutrition goals. Returns all 14 tracked nutrient targets."
    )]
    async fn get_goals(&self) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;

        let row = sqlx::query("SELECT goals FROM daily_goal WHERE id = 1")
            .fetch_one(&pool)
            .await
            .map_err(|e| McpError::internal_error(format!("Goals query failed: {e}"), None))?;

        let goals_str: String = row.try_get("goals").map_err(|e| McpError::internal_error(e.to_string(), None))?;
        let goals: Value = serde_json::from_str(&goals_str).unwrap_or(json!({}));

        ok(serde_json::to_string_pretty(&json!({
            "daily_goals": goals,
            "tracked_nutrients": TRACKED_NUTRIENTS.iter().map(|(display, off)| {
                json!({"display": display, "off_field": off})
            }).collect::<Vec<_>>()
        }))
        .unwrap_or_default())
    }

    #[tool(
        description = "Set daily nutrition goals. Accepts partial updates (merged with existing). \
                       Keys: energy_kcal, protein, carbohydrates, fat, fiber, sugars, saturated_fat, \
                       salt, fructose, alcohol, potassium, calcium, magnesium, cholesterol."
    )]
    async fn set_goals(
        &self,
        Parameters(params): Parameters<SetGoalsParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;

        // Get existing goals
        let row = sqlx::query("SELECT goals FROM daily_goal WHERE id = 1")
            .fetch_one(&pool)
            .await
            .map_err(|e| McpError::internal_error(format!("Goals query failed: {e}"), None))?;

        let existing_str: String = row.try_get("goals").map_err(|e| McpError::internal_error(e.to_string(), None))?;
        let mut existing: Value = serde_json::from_str(&existing_str).unwrap_or(json!({}));

        // Merge new goals into existing
        if let (Some(existing_obj), Some(new_obj)) = (existing.as_object_mut(), params.goals.as_object()) {
            for (k, v) in new_obj {
                existing_obj.insert(k.clone(), v.clone());
            }
        }

        // Save
        sqlx::query("UPDATE daily_goal SET goals = ?, updated_at = datetime('now') WHERE id = 1")
            .bind(existing.to_string())
            .execute(&pool)
            .await
            .map_err(|e| McpError::internal_error(format!("Goals update failed: {e}"), None))?;

        ok(format!("✓ Updated daily goals:\n{}", serde_json::to_string_pretty(&existing).unwrap_or_default()))
    }

    // ── Weight ───────────────────────────────────────────────────

    #[tool(
        description = "Log body weight in kilograms for a date (default: today)."
    )]
    async fn log_weight(
        &self,
        Parameters(params): Parameters<LogWeightParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;
        let date = params.date.unwrap_or_else(today);

        sqlx::query(
            r#"INSERT INTO weight_log (date, weight_kg) VALUES (?, ?)
               ON CONFLICT DO UPDATE SET weight_kg = excluded.weight_kg, created_at = datetime('now')"#,
        )
        .bind(&date)
        .bind(params.weight_kg)
        .execute(&pool)
        .await
        .map_err(|e| McpError::internal_error(format!("Weight insert failed: {e}"), None))?;

        ok(format!("✓ Logged weight: {} kg ({})", params.weight_kg, date))
    }

    #[tool(
        description = "Show weight history for the last N days (default 30)."
    )]
    async fn weight_history(
        &self,
        Parameters(params): Parameters<WeightHistoryParams>,
    ) -> Result<CallToolResult, McpError> {
        let pool = self.pool().await?;
        let days = params.days.unwrap_or(30);

        let rows = sqlx::query(
            r#"SELECT date, weight_kg FROM weight_log
               WHERE date >= date('now', ?)
               ORDER BY date DESC"#,
        )
        .bind(format!("-{} days", days))
        .fetch_all(&pool)
        .await
        .map_err(|e| McpError::internal_error(format!("Weight history query failed: {e}"), None))?;

        if rows.is_empty() {
            return ok(format!("No weight entries in the last {} days", days));
        }

        let mut entries = Vec::new();
        for row in rows {
            let date: String = row.try_get("date").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let weight_kg: f64 = row.try_get("weight_kg").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            entries.push(json!({"date": date, "weight_kg": weight_kg}));
        }

        ok(serde_json::to_string_pretty(&json!({
            "days": days,
            "weight_log": entries
        }))
        .unwrap_or_default())
    }

    // ── Future: Bulk Import ──────────────────────────────────────

    #[tool(
        description = "Bulk import OpenFood Facts data from a Parquet file for offline use. \
                       NOT YET IMPLEMENTED — stub for future offline mode."
    )]
    async fn bulk_import(
        &self,
        Parameters(_params): Parameters<BulkImportParams>,
    ) -> Result<CallToolResult, McpError> {
        ok(
            "Not yet implemented. Future: download HuggingFace Parquet export, \
             extract relevant columns (code, product_name, brands, nutriments, \
             serving_quantity, serving_size, image_url), bulk insert into products \
             table, rebuild FTS5 index."
                .to_string(),
        )
    }
}

// ── Daily summary helper ────────────────────────────────────────────

impl NutritionServer {
    async fn build_daily_summary(&self, pool: &sqlx::SqlitePool, date: &str) -> Result<String, McpError> {
        // Fetch entries
        let rows = sqlx::query(
            r#"SELECT id, meal, food_name, grams, nutriments FROM entries WHERE date = ? ORDER BY created_at"#,
        )
        .bind(date)
        .fetch_all(pool)
        .await
        .map_err(|e| McpError::internal_error(format!("Summary query failed: {e}"), None))?;

        let entry_count = rows.len();
        let mut entries_nutriments: Vec<Value> = Vec::new();
        let mut entry_list: Vec<Value> = Vec::new();

        for row in &rows {
            let id: i64 = row.try_get("id").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let meal: String = row.try_get("meal").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let food_name: String = row.try_get("food_name").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let grams: Option<f64> = row.try_get("grams").unwrap_or(None);
            let nutriments_str: String = row.try_get("nutriments").map_err(|e| McpError::internal_error(e.to_string(), None))?;
            let n: Value = serde_json::from_str(&nutriments_str).unwrap_or(json!({}));
            entries_nutriments.push(n.clone());
            entry_list.push(json!({"id": id, "meal": meal, "food_name": food_name, "grams": grams}));
        }

        let totals = sum_nutriments(&entries_nutriments);

        // Get goals
        let goals_row = sqlx::query("SELECT goals FROM daily_goal WHERE id = 1")
            .fetch_one(pool)
            .await
            .map_err(|e| McpError::internal_error(format!("Goals query failed: {e}"), None))?;
        let goals_str: String = goals_row.try_get("goals").map_err(|e| McpError::internal_error(e.to_string(), None))?;
        let goals: Value = serde_json::from_str(&goals_str).unwrap_or(json!({}));

        // Calculate remaining for key nutrients
        let remaining = |key: &str| -> Value {
            let consumed = totals.get(key).and_then(|v| v.as_f64()).unwrap_or(0.0);
            let goal = goals.get(key).and_then(|v| v.as_f64()).unwrap_or(0.0);
            json!(goal - consumed)
        };

        Ok(serde_json::to_string_pretty(&json!({
            "date": date,
            "entries": entry_count,
            "totals": totals,
            "goals": goals,
            "remaining": {
                "energy_kcal": remaining("energy-kcal"),
                "protein": remaining("protein"),
                "fructose": remaining("fructose"),
                "salt": remaining("salt"),
                "potassium": remaining("potassium"),
            },
            "entry_list": entry_list
        }))
        .unwrap_or_default())
    }
}

// ── ServerHandler impl ──────────────────────────────────────────────

#[tool_handler]
impl ServerHandler for NutritionServer {
    fn get_info(&self) -> ServerInfo {
        ServerInfo {
            server_info: Implementation {
                name: "nutrition-mcp".into(),
                version: "0.1.0".into(),
                title: Some("Nutrition Tracker".into()),
                icons: None,
                website_url: None,
            },
            capabilities: ServerCapabilities::builder()
                .enable_tools()
                .build(),
            instructions: Some(
                "Personal nutrition tracking MCP server. Tools: search_food (find food by name), \
                 get_food_by_barcode (lookup by barcode), log_food (log OFF product with portions), \
                 log_custom_food (log homemade/restaurant food), delete_entry, daily_summary, \
                 history, list_entries, get_goals, set_goals, log_weight, weight_history, \
                 bulk_import (stub). Tracks 14 nutrients including gout (fructose, alcohol) and \
                 hypertension (salt, potassium, calcium, magnesium, cholesterol) markers."
                    .into(),
            ),
            ..Default::default()
        }
    }
}