use std::collections::HashMap;

use chrono::{Datelike, NaiveDate};
use common_contracts::dtos::TimeSeriesFinancialDto;
use itertools::Itertools;
use rust_decimal::Decimal;
use rust_decimal::prelude::*;
use rust_decimal_macros::dec;

use crate::{
    error::ProviderError,
    tushare::{
        BalanceSheet, Cashflow, Dividend, FinaIndicator, Income, Repurchase, StkHolderNumber,
    },
};

pub struct TushareFinancials {
    pub balancesheet: Vec<BalanceSheet>,
    pub income: Vec<Income>,
    pub cashflow: Vec<Cashflow>,
    pub fina_indicator: Vec<FinaIndicator>,
    pub repurchase: Vec<Repurchase>,
    pub dividend: Vec<Dividend>,
    pub stk_holdernumber: Vec<StkHolderNumber>,
    pub employees: Option<f64>,
}

pub fn map_financial_statements(
    symbol: &str,
    raw_data: TushareFinancials,
) -> Result<Vec<TimeSeriesFinancialDto>, ProviderError> {
    // 1. Merge all financial data by end_date
    let mut by_date = merge_financial_data(&raw_data);

    // 2. Filter for wanted report dates
    let wanted_dates = filter_wanted_dates(by_date.keys().cloned().collect());
    let statements_with_periods: Vec<(String, HashMap<String, f64>)> = wanted_dates
        .clone()
        .into_iter()
        .filter_map(|d| by_date.remove(&d).map(|m| (d, m)))
        .collect();

    // 3. Transform into a series map (metric -> Vec<{period, value}>)
    let mut series = transform_to_series_with_periods(&statements_with_periods);

    // 4. Process special data (repurchase, dividend, etc.)
    let current_year_str = chrono::Utc::now().year().to_string();
    let latest_current_year_report = wanted_dates.iter().find(|d| d.starts_with(&current_year_str)).cloned();
    process_special_data(&mut series, &raw_data, &current_year_str, latest_current_year_report);

    // 5. Calculate derived metrics
    calculate_derived_metrics(&mut series);
    
    // 6. 扁平化为 TimeSeriesFinancialDto
    flatten_series_to_dtos(symbol, series)
}

fn merge_financial_data(
    raw_data: &TushareFinancials,
) -> HashMap<String, HashMap<String, f64>> {
    let mut by_date: HashMap<String, HashMap<String, f64>> = HashMap::new();

    macro_rules! merge {
        ($rows:expr, $($field:ident),+) => {
            for r in $rows {
                if let Some(end_date) = &r.end_date {
                    let entry = by_date.entry(end_date.clone()).or_default();
                    $(
                        if let Some(val) = r.$field {
                            entry.insert(stringify!($field).to_string(), val);
                        }
                    )+
                }
            }
        };
    }
    
    merge!(&raw_data.balancesheet, money_cap, inventories, accounts_receiv, prepayment, fix_assets, lt_eqt_invest, goodwill, accounts_pay, adv_receipts, contract_liab, st_borr, lt_borr, total_assets);
    merge!(&raw_data.income, revenue, sell_exp, admin_exp, rd_exp, grossprofit_margin, netprofit_margin, n_income);
    merge!(&raw_data.cashflow, n_cashflow_act, c_pay_acq_const_fiolta, depr_fa_coga_dpba, c_paid_to_for_empl);
    merge!(&raw_data.fina_indicator, tax_to_ebt, arturn_days);

    by_date
}

fn filter_wanted_dates(dates: Vec<String>) -> Vec<String> {
    let current_year = chrono::Utc::now().year().to_string();
    let mut all_available_dates = dates;
    all_available_dates.sort_by(|a, b| b.cmp(a)); // Sort descending

    let latest_current_year_report = all_available_dates
        .iter()
        .find(|d| d.starts_with(&current_year))
        .cloned();

    let mut wanted_dates: Vec<String> = Vec::new();
    if let Some(d) = latest_current_year_report {
        wanted_dates.push(d);
    }

    let previous_years_annual_reports = all_available_dates
        .into_iter()
        .filter(|d| d.ends_with("1231") && !d.starts_with(&current_year));
    
    wanted_dates.extend(previous_years_annual_reports);
    wanted_dates
}

#[derive(Debug, Clone)]
struct SeriesPoint { period: String, value: f64 }
type SeriesMap = HashMap<String, Vec<SeriesPoint>>;

fn transform_to_series_with_periods(statements: &[(String, HashMap<String, f64>)]) -> SeriesMap {
    let mut series: SeriesMap = HashMap::new();
    for (period, report) in statements {
             for (key, value) in report {
            series
                .entry(key.clone())
                .or_default()
                .push(SeriesPoint { period: period.clone(), value: *value });
        }
    }
    series
}

fn process_special_data(series: &mut SeriesMap, raw_data: &TushareFinancials, current_year: &str, latest_report: Option<String>) {
    // Employees
    if let Some(employees) = raw_data.employees {
        let prev_year = chrono::Utc::now().year() - 1;
        series.entry("employees".to_string()).or_default().push(SeriesPoint {
            period: format!("{}1231", prev_year),
            value: employees,
        });
    }

    // Holder Numbers（取每期按最新公告日聚合）
    let mut holder_by_period: HashMap<String, (String, f64)> = HashMap::new();
    for r in &raw_data.stk_holdernumber {
        if let (Some(end_date), Some(ann_date), Some(holder_num)) = (&r.end_date, &r.ann_date, r.holder_num) {
            let entry = holder_by_period.entry(end_date.clone()).or_insert((ann_date.clone(), holder_num));
            if ann_date > &entry.0 {
                *entry = (ann_date.clone(), holder_num);
            }
        }
    }
    if !holder_by_period.is_empty() {
        let mut holder_series: Vec<SeriesPoint> = Vec::new();
        for (period, (_ann, num)) in holder_by_period.into_iter() {
            holder_series.push(SeriesPoint { period, value: num });
        }
        series.insert("holder_num".to_string(), holder_series);
    }
    
    // Dividend
    let mut div_by_year: HashMap<String, f64> = HashMap::new();
    for r in &raw_data.dividend {
        if let (Some(pay_date), Some(cash_div), Some(base_share)) = (&r.pay_date, r.cash_div_tax, r.base_share) {
            if pay_date.len() >= 4 {
                let year = &pay_date[..4];
                let amount_billion = (cash_div * base_share) / 10000.0;
                *div_by_year.entry(year.to_string()).or_default() += amount_billion;
            }
        }
    }
    if !div_by_year.is_empty() {
        let div_series = div_by_year.into_iter().map(|(year, amount)| {
            let period_key = if &year == current_year && latest_report.is_some() {
                latest_report.clone().unwrap()
            } else {
                format!("{}1231", year)
            };
            SeriesPoint { period: period_key, value: amount }
        }).collect();
        series.insert("dividend_amount".to_string(), div_series);
    }

    // Repurchase (simplified)
    // A full implementation would be more complex, matching python logic
}


fn calculate_derived_metrics(series: &mut SeriesMap) {
    let periods: Vec<String> = series.values().flatten().map(|p| p.period.clone()).unique().collect();

    let get_value = |key: &str, period: &str, s: &SeriesMap| -> Option<Decimal> {
        s.get(key)
            .and_then(|v| v.iter().find(|p| p.period == period))
            .and_then(|p| Decimal::from_f64(p.value))
    };
    
    let get_avg_value = |key: &str, period: &str, s: &SeriesMap| -> Option<Decimal> {
        let current_val = get_value(key, period, s)?;
        let prev_year = period[..4].parse::<i32>().ok()? - 1;
        let prev_period = format!("{}1231", prev_year);
        let prev_val = get_value(key, &prev_period, s);
        Some( (current_val + prev_val.unwrap_or(current_val)) / dec!(2) )
    };

    let get_cogs = |period: &str, s: &SeriesMap| -> Option<Decimal> {
        let revenue = get_value("revenue", period, s)?;
        let gp_margin_raw = get_value("grossprofit_margin", period, s)?;
        let gp_margin = if gp_margin_raw.abs() > dec!(1) { gp_margin_raw / dec!(100) } else { gp_margin_raw };
        Some(revenue * (dec!(1) - gp_margin))
    };

    let mut new_series: SeriesMap = HashMap::new();

    for period in &periods {
        // Fee Calcs
        let fee_calcs = [
            ("__sell_rate", "sell_exp"), ("__admin_rate", "admin_exp"), ("__rd_rate", "rd_exp"), ("__depr_ratio", "depr_fa_coga_dpba")
        ];
        for (key, num_key) in fee_calcs {
            if let (Some(num), Some(den)) = (get_value(num_key, period, series), get_value("revenue", period, series)) {
                if !den.is_zero() {
                    new_series.entry(key.to_string()).or_default().push(SeriesPoint { period: period.clone(), value: ((num / den) * dec!(100)).to_f64().unwrap() });
        }
    }
        }
        
        // Asset Ratios
        let asset_ratio_keys = [
            ("__money_cap_ratio", "money_cap"), ("__inventories_ratio", "inventories"), ("__ar_ratio", "accounts_receiv"), 
            ("__prepay_ratio", "prepayment"), ("__fix_assets_ratio", "fix_assets"), ("__lt_invest_ratio", "lt_eqt_invest"),
            ("__goodwill_ratio", "goodwill"), ("__ap_ratio", "accounts_pay"), ("__st_borr_ratio", "st_borr"), ("__lt_borr_ratio", "lt_borr"),
        ];
        for (key, num_key) in asset_ratio_keys {
             if let (Some(num), Some(den)) = (get_value(num_key, period, series), get_value("total_assets", period, series)) {
                if !den.is_zero() {
                    new_series.entry(key.to_string()).or_default().push(SeriesPoint { period: period.clone(), value: ((num / den) * dec!(100)).to_f64().unwrap() });
                }
            }
        }

        // Other derived metrics...
        if let Some(tax_to_ebt) = get_value("tax_to_ebt", period, series) {
            let rate = if tax_to_ebt.abs() <= dec!(1) { tax_to_ebt * dec!(100) } else { tax_to_ebt };
            new_series.entry("__tax_rate".to_string()).or_default().push(SeriesPoint { period: period.clone(), value: rate.to_f64().unwrap() });
        }

        if let Some(avg_ap) = get_avg_value("accounts_pay", period, series) {
            if let Some(cogs) = get_cogs(period, series) {
                if !cogs.is_zero() {
                     new_series.entry("payturn_days".to_string()).or_default().push(SeriesPoint { period: period.clone(), value: ((dec!(365) * avg_ap) / cogs).to_f64().unwrap() });
                }
            }
        }
        // ... continue for all other metrics from python
    }
    
    series.extend(new_series);
}

fn flatten_series_to_dtos(symbol: &str, series: SeriesMap) -> Result<Vec<TimeSeriesFinancialDto>, ProviderError> {
    let mut dtos: Vec<TimeSeriesFinancialDto> = Vec::new();
    for (metric_name, data_points) in series {
        for point in data_points {
            let period_date = NaiveDate::parse_from_str(&point.period, "%Y%m%d")
                .map_err(|e| ProviderError::Mapping(format!("Invalid period '{}': {}", point.period, e)))?;
            dtos.push(TimeSeriesFinancialDto {
                symbol: symbol.to_string(),
                metric_name: metric_name.clone(),
                period_date,
                value: point.value,
                source: Some("tushare".to_string()),
            });
    }
}
    Ok(dtos)
}


// （去除旧的 FinancialStatement 映射辅助）