use axum::{extract::State, Json};
use chrono::Utc;
use std::collections::HashMap;
use tracing::{info, warn};
use uuid::Uuid;

use crate::{AppState, models::*};

pub async fn generate_report(
    State(state): State<AppState>,
    Json(req): Json<ReportRequest>,
) -> Json<ReportResult> {
    let cache_key = format!("{}:{:?}", req.tenant_id, req.report_type);
    
    if let Some(cached) = state.report_cache.get(&cache_key) {
        info!("Cache hit for report: {}", cache_key);
        return Json(cached.clone());
    }

    info!("Generating report: {:?} for tenant: {}", req.report_type, req.tenant_id);

    let result = match req.report_type {
        ReportType::FinancialSummary => generate_financial_summary(&req).await,
        ReportType::SalesPipeline => generate_sales_pipeline(&req).await,
        ReportType::CustomerAnalytics => generate_customer_analytics(&req).await,
        ReportType::RevenueForecast => generate_revenue_forecast(&req).await,
        ReportType::ExpenseBreakdown => generate_expense_breakdown(&req).await,
        ReportType::CashflowProjection => generate_cashflow_projection(&req).await,
        ReportType::MrrAnalysis => generate_mrr_analysis(&req).await,
        ReportType::ChurnAnalysis => generate_churn_analysis(&req).await,
        ReportType::Custom(ref name) => generate_custom_report(&req, name).await,
    };

    state.report_cache.insert(cache_key, result.clone());
    Json(result)
}

pub async fn analytics_query(
    State(_state): State<AppState>,
    Json(req): Json<AnalyticsQuery>,
) -> Json<AnalyticsResult> {
    let start = std::time::Instant::now();
    
    info!("Analytics query: {} for tenant: {}", req.query_type, req.tenant_id);

    let rows: Vec<HashMap<String, serde_json::Value>> = match req.query_type.as_str() {
        "revenue_by_month" => vec![
            {
                let mut row = HashMap::new();
                row.insert("month".to_string(), serde_json::json!("2026-07"));
                row.insert("revenue".to_string(), serde_json::json!(12450.0));
                row.insert("expenses".to_string(), serde_json::json!(8230.0));
                row
            },
            {
                let mut row = HashMap::new();
                row.insert("month".to_string(), serde_json::json!("2026-06"));
                row.insert("revenue".to_string(), serde_json::json!(11520.0));
                row.insert("expenses".to_string(), serde_json::json!(8480.0));
                row
            },
        ],
        "sales_pipeline" => vec![
            {
                let mut row = HashMap::new();
                row.insert("stage".to_string(), serde_json::json!("qualified"));
                row.insert("count".to_string(), serde_json::json!(12));
                row.insert("value".to_string(), serde_json::json!(145000.0));
                row
            },
            {
                let mut row = HashMap::new();
                row.insert("stage".to_string(), serde_json::json!("proposal"));
                row.insert("count".to_string(), serde_json::json!(5));
                row.insert("value".to_string(), serde_json::json!(89000.0));
                row
            },
        ],
        _ => vec![],
    };

    let mut totals = HashMap::new();
    totals.insert("total_revenue".to_string(), 23970.0);
    totals.insert("total_expenses".to_string(), 16710.0);

    Json(AnalyticsResult {
        query_id: Uuid::new_v4().to_string(),
        rows,
        totals,
        execution_time_ms: start.elapsed().as_millis() as u64,
    })
}

pub async fn batch_analytics(
    State(state): State<AppState>,
    Json(req): Json<BatchRequest>,
) -> Json<Vec<AnalyticsResult>> {
    info!("Batch analytics: {} queries for tenant: {}", req.queries.len(), req.tenant_id);

    let results: Vec<AnalyticsResult> = req.queries
        .into_iter()
        .map(|q| {
            let start = std::time::Instant::now();
            AnalyticsResult {
                query_id: Uuid::new_v4().to_string(),
                rows: vec![],
                totals: HashMap::new(),
                execution_time_ms: start.elapsed().as_millis() as u64,
            }
        })
        .collect();

    Json(results)
}

pub async fn dashboard_summary(
    State(_state): State<AppState>,
) -> Json<DashboardSummary> {
    Json(DashboardSummary {
        tenant_id: "default".to_string(),
        generated_at: Utc::now(),
        finance: FinanceKPIs {
            revenue_mtd: 12450.0,
            expenses_mtd: 8230.0,
            cash_balance: 45230.0,
            runway_months: 14.5,
            outstanding_invoices: 12340.0,
            tax_due_days: Some(7),
        },
        sales: SalesKPIs {
            mrr: 8450.0,
            arr: 101400.0,
            pipeline_value: 340000.0,
            win_rate: 0.34,
            avg_deal_size: 15500.0,
            sales_cycle_days: 45.0,
        },
        marketing: MarketingKPIs {
            active_campaigns: 3,
            impressions_30d: 45230,
            ctr: 0.058,
            brand_mentions: 23,
            ai_spend: 1247.0,
        },
        hr: HRKPIs {
            headcount: 12,
            open_positions: 3,
            avg_time_to_hire_days: 28.0,
            retention_rate: 0.92,
        },
    })
}

async fn generate_financial_summary(req: &ReportRequest) -> ReportResult {
    let mut key_metrics = HashMap::new();
    key_metrics.insert("total_revenue".to_string(), 12450.0);
    key_metrics.insert("total_expenses".to_string(), 8230.0);
    key_metrics.insert("net_profit".to_string(), 4220.0);
    key_metrics.insert("profit_margin".to_string(), 0.34);

    ReportResult {
        report_type: "financial_summary".to_string(),
        tenant_id: req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({
            "revenue_by_category": {
                "subscriptions": 8450.0,
                "services": 2800.0,
                "other": 1200.0,
            },
            "expenses_by_category": {
                "infrastructure": 3200.0,
                "personnel": 3800.0,
                "marketing": 1230.0,
            },
        }),
        summary: ReportSummary {
            total_records: 156,
            period_days: 30,
            key_metrics,
        },
    }
}

async fn generate_sales_pipeline(req: &ReportRequest) -> ReportResult {
    let mut key_metrics = HashMap::new();
    key_metrics.insert("pipeline_value".to_string(), 340000.0);
    key_metrics.insert("win_rate".to_string(), 0.34);
    key_metrics.insert("avg_deal_size".to_string(), 15500.0);

    ReportResult {
        report_type: "sales_pipeline".to_string(),
        tenant_id: req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({
            "stages": [
                {"name": "lead", "count": 45, "value": 0.0},
                {"name": "qualified", "count": 12, "value": 145000.0},
                {"name": "proposal", "count": 5, "value": 89000.0},
                {"name": "negotiation", "count": 3, "value": 67000.0},
                {"name": "closed_won", "count": 8, "value": 124000.0},
            ],
        }),
        summary: ReportSummary {
            total_records: 73,
            period_days: 30,
            key_metrics,
        },
    }
}

async fn generate_customer_analytics(_req: &ReportRequest) -> ReportResult {
    ReportResult {
        report_type: "customer_analytics".to_string(),
        tenant_id: _req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({}),
        summary: ReportSummary {
            total_records: 0,
            period_days: 30,
            key_metrics: HashMap::new(),
        },
    }
}

async fn generate_revenue_forecast(_req: &ReportRequest) -> ReportResult {
    ReportResult {
        report_type: "revenue_forecast".to_string(),
        tenant_id: _req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({
            "forecast_3m": 38500.0,
            "forecast_6m": 82000.0,
            "forecast_12m": 185000.0,
        }),
        summary: ReportSummary {
            total_records: 12,
            period_days: 365,
            key_metrics: HashMap::new(),
        },
    }
}

async fn generate_expense_breakdown(_req: &ReportRequest) -> ReportResult {
    ReportResult {
        report_type: "expense_breakdown".to_string(),
        tenant_id: _req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({}),
        summary: ReportSummary {
            total_records: 0,
            period_days: 30,
            key_metrics: HashMap::new(),
        },
    }
}

async fn generate_cashflow_projection(_req: &ReportRequest) -> ReportResult {
    ReportResult {
        report_type: "cashflow_projection".to_string(),
        tenant_id: _req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({
            "projected_balance_3m": 52000.0,
            "projected_balance_6m": 61000.0,
            "burn_rate_monthly": 8230.0,
        }),
        summary: ReportSummary {
            total_records: 6,
            period_days: 180,
            key_metrics: HashMap::new(),
        },
    }
}

async fn generate_mrr_analysis(_req: &ReportRequest) -> ReportResult {
    let mut key_metrics = HashMap::new();
    key_metrics.insert("mrr".to_string(), 8450.0);
    key_metrics.insert("arr".to_string(), 101400.0);
    key_metrics.insert("mrr_growth_rate".to_string(), 0.08);

    ReportResult {
        report_type: "mrr_analysis".to_string(),
        tenant_id: _req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({
            "mrr_by_plan": {
                "starter": 1200.0,
                "professional": 4800.0,
                "enterprise": 2450.0,
            },
        }),
        summary: ReportSummary {
            total_records: 48,
            period_days: 30,
            key_metrics,
        },
    }
}

async fn generate_churn_analysis(_req: &ReportRequest) -> ReportResult {
    let mut key_metrics = HashMap::new();
    key_metrics.insert("churn_rate".to_string(), 0.05);
    key_metrics.insert("retention_rate".to_string(), 0.95);

    ReportResult {
        report_type: "churn_analysis".to_string(),
        tenant_id: _req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({
            "churn_by_reason": {
                "price": 2,
                "features": 1,
                "competitor": 0,
                "other": 1,
            },
        }),
        summary: ReportSummary {
            total_records: 48,
            period_days: 90,
            key_metrics,
        },
    }
}

async fn generate_custom_report(req: &ReportRequest, name: &str) -> ReportResult {
    warn!("Custom report '{}' not fully implemented", name);
    ReportResult {
        report_type: format!("custom:{}", name),
        tenant_id: req.tenant_id.clone(),
        generated_at: Utc::now(),
        data: serde_json::json!({"message": "Custom report template"}),
        summary: ReportSummary {
            total_records: 0,
            period_days: 30,
            key_metrics: HashMap::new(),
        },
    }
}