datasynth_generators/document_flow/

document_flow_je_generator.rs

//! Generate journal entries from document flows.
//!
//! This module creates proper GL entries from P2P and O2C document chains,
//! ensuring that document flow activity is reflected in the general ledger.
//!
//! # P2P Flow JE Mappings
//! - GoodsReceipt → DR Inventory, CR GR/IR Clearing
//! - VendorInvoice → DR GR/IR Clearing (net), DR Input VAT (tax), CR AP (gross)
//! - Payment → DR AP, CR Cash
//!
//! # O2C Flow JE Mappings
//! - Delivery → DR COGS, CR Inventory
//! - CustomerInvoice → DR AR (gross), CR Revenue (net), CR VAT Payable (tax)
//! - CustomerReceipt → DR Cash, CR AR

use std::collections::HashMap;

use chrono::NaiveDate;
use rust_decimal::Decimal;

use datasynth_core::accounts::{
    cash_accounts, control_accounts, expense_accounts, revenue_accounts, tax_accounts,
};
use datasynth_core::models::{
    documents::{CustomerInvoice, Delivery, GoodsReceipt, Payment, VendorInvoice},
    BusinessProcess, JournalEntry, JournalEntryHeader, JournalEntryLine, TransactionSource,
};
use datasynth_core::uuid_factory::{DeterministicUuidFactory, GeneratorType};

use super::{O2CDocumentChain, P2PDocumentChain};

/// Configuration for document flow JE generation.
#[derive(Debug, Clone)]
pub struct DocumentFlowJeConfig {
    /// Inventory account (default: 1200 from control_accounts::INVENTORY)
    pub inventory_account: String,
    /// GR/IR clearing account (default: 2900 from control_accounts::GR_IR_CLEARING)
    pub gr_ir_clearing_account: String,
    /// Accounts payable control account (default: 2000 from control_accounts::AP_CONTROL)
    pub ap_account: String,
    /// Cash/bank account (default: 1000 from cash_accounts::OPERATING_CASH)
    pub cash_account: String,
    /// Accounts receivable control account (default: 1100 from control_accounts::AR_CONTROL)
    pub ar_account: String,
    /// Revenue account (default: 4000 from revenue_accounts::PRODUCT_REVENUE)
    pub revenue_account: String,
    /// COGS account (default: 5000 from expense_accounts::COGS)
    pub cogs_account: String,
    /// VAT output (payable) account for O2C (default: 2110 from tax_accounts::VAT_PAYABLE)
    pub vat_output_account: String,
    /// VAT input (receivable) account for P2P (default: 1160 from tax_accounts::INPUT_VAT)
    pub vat_input_account: String,
    /// Whether to populate FEC auxiliary and lettrage fields on AP/AR lines.
    /// Only relevant for French GAAP / FEC export.
    pub populate_fec_fields: bool,
}

impl Default for DocumentFlowJeConfig {
    fn default() -> Self {
        Self {
            inventory_account: control_accounts::INVENTORY.to_string(),
            gr_ir_clearing_account: control_accounts::GR_IR_CLEARING.to_string(),
            ap_account: control_accounts::AP_CONTROL.to_string(),
            cash_account: cash_accounts::OPERATING_CASH.to_string(),
            ar_account: control_accounts::AR_CONTROL.to_string(),
            revenue_account: revenue_accounts::PRODUCT_REVENUE.to_string(),
            cogs_account: expense_accounts::COGS.to_string(),
            vat_output_account: tax_accounts::VAT_PAYABLE.to_string(),
            vat_input_account: tax_accounts::INPUT_VAT.to_string(),
            populate_fec_fields: false,
        }
    }
}

impl DocumentFlowJeConfig {
    /// Create a config for French GAAP (PCG) with FEC field population enabled.
    pub fn french_gaap() -> Self {
        use datasynth_core::pcg;
        Self {
            inventory_account: pcg::control_accounts::INVENTORY.to_string(),
            gr_ir_clearing_account: pcg::control_accounts::GR_IR_CLEARING.to_string(),
            ap_account: pcg::control_accounts::AP_CONTROL.to_string(),
            cash_account: pcg::cash_accounts::BANK_ACCOUNT.to_string(),
            ar_account: pcg::control_accounts::AR_CONTROL.to_string(),
            revenue_account: pcg::revenue_accounts::PRODUCT_REVENUE.to_string(),
            cogs_account: pcg::expense_accounts::COGS.to_string(),
            vat_output_account: pcg::tax_accounts::OUTPUT_VAT.to_string(),
            vat_input_account: pcg::tax_accounts::INPUT_VAT.to_string(),
            populate_fec_fields: true,
        }
    }
}

impl From<&datasynth_core::FrameworkAccounts> for DocumentFlowJeConfig {
    fn from(fa: &datasynth_core::FrameworkAccounts) -> Self {
        Self {
            inventory_account: fa.inventory.clone(),
            gr_ir_clearing_account: fa.gr_ir_clearing.clone(),
            ap_account: fa.ap_control.clone(),
            cash_account: fa.bank_account.clone(),
            ar_account: fa.ar_control.clone(),
            revenue_account: fa.product_revenue.clone(),
            cogs_account: fa.cogs.clone(),
            vat_output_account: fa.vat_payable.clone(),
            vat_input_account: fa.input_vat.clone(),
            populate_fec_fields: fa.audit_export.fec_enabled,
        }
    }
}

/// Generator for creating JEs from document flows.
pub struct DocumentFlowJeGenerator {
    config: DocumentFlowJeConfig,
    uuid_factory: DeterministicUuidFactory,
    /// Lookup map: partner_id → auxiliary GL account number.
    /// When populated (from vendor/customer master data), `set_auxiliary_fields`
    /// uses the framework-specific auxiliary account (e.g., PCG "4010001", SKR04 "33000001")
    /// instead of the raw partner ID.
    auxiliary_account_lookup: HashMap<String, String>,
}

impl DocumentFlowJeGenerator {
    /// Create a new document flow JE generator with default config and seed 0.
    pub fn new() -> Self {
        Self::with_config_and_seed(DocumentFlowJeConfig::default(), 0)
    }

    /// Create with custom account configuration and seed.
    pub fn with_config_and_seed(config: DocumentFlowJeConfig, seed: u64) -> Self {
        Self {
            config,
            uuid_factory: DeterministicUuidFactory::new(seed, GeneratorType::DocumentFlow),
            auxiliary_account_lookup: HashMap::new(),
        }
    }

    /// Set the auxiliary account lookup map (partner_id → auxiliary GL account).
    ///
    /// When populated, FEC `auxiliary_account_number` fields will use the
    /// framework-specific auxiliary GL account (e.g., PCG "4010001") instead
    /// of the raw partner ID.
    pub fn set_auxiliary_account_lookup(&mut self, lookup: HashMap<String, String>) {
        self.auxiliary_account_lookup = lookup;
    }

    /// Set auxiliary account fields on AP/AR lines when FEC population is enabled.
    ///
    /// Only sets the fields if `populate_fec_fields` is true and the line's
    /// GL account matches the configured AP or AR control account.
    ///
    /// When an auxiliary account lookup is available, uses the framework-specific
    /// auxiliary GL account (e.g., PCG "4010001", SKR04 "33000001") instead of
    /// the raw partner ID.
    fn set_auxiliary_fields(
        &self,
        line: &mut JournalEntryLine,
        partner_id: &str,
        partner_label: &str,
    ) {
        if !self.config.populate_fec_fields {
            return;
        }
        if line.gl_account == self.config.ap_account || line.gl_account == self.config.ar_account {
            // Prefer the framework-specific auxiliary GL account from the lookup map;
            // fall back to the raw partner ID if not found.
            let aux_account = self
                .auxiliary_account_lookup
                .get(partner_id)
                .cloned()
                .unwrap_or_else(|| partner_id.to_string());
            line.auxiliary_account_number = Some(aux_account);
            line.auxiliary_account_label = Some(partner_label.to_string());
        }
    }

    /// Apply lettrage (matching) codes to all AP/AR lines in a set of entries.
    ///
    /// Only sets lettrage if `populate_fec_fields` is true. The lettrage code
    /// is derived from the chain ID (e.g. PO or SO document ID) and the date
    /// is typically the final payment's posting date.
    fn apply_lettrage(
        &self,
        entries: &mut [JournalEntry],
        chain_id: &str,
        lettrage_date: NaiveDate,
    ) {
        if !self.config.populate_fec_fields {
            return;
        }
        let code = format!("LTR-{}", &chain_id[..chain_id.len().min(8)]);
        for entry in entries.iter_mut() {
            for line in entry.lines.iter_mut() {
                if line.gl_account == self.config.ap_account
                    || line.gl_account == self.config.ar_account
                {
                    line.lettrage = Some(code.clone());
                    line.lettrage_date = Some(lettrage_date);
                }
            }
        }
    }

    /// Generate all JEs from a P2P document chain.
    pub fn generate_from_p2p_chain(&mut self, chain: &P2PDocumentChain) -> Vec<JournalEntry> {
        let mut entries = Vec::new();

        // Generate JEs for goods receipts
        for gr in &chain.goods_receipts {
            if let Some(je) = self.generate_from_goods_receipt(gr) {
                entries.push(je);
            }
        }

        // Generate JE for vendor invoice
        if let Some(ref invoice) = chain.vendor_invoice {
            if let Some(je) = self.generate_from_vendor_invoice(invoice) {
                entries.push(je);
            }
        }

        // Generate JE for payment
        if let Some(ref payment) = chain.payment {
            if let Some(je) = self.generate_from_ap_payment(payment) {
                entries.push(je);
            }
        }

        // Generate JEs for remainder payments
        for payment in &chain.remainder_payments {
            if let Some(je) = self.generate_from_ap_payment(payment) {
                entries.push(je);
            }
        }

        // Apply lettrage on complete P2P chains (invoice + payment both present)
        if self.config.populate_fec_fields && chain.is_complete {
            if let Some(ref payment) = chain.payment {
                let posting_date = payment
                    .header
                    .posting_date
                    .unwrap_or(payment.header.document_date);
                self.apply_lettrage(
                    &mut entries,
                    &chain.purchase_order.header.document_id,
                    posting_date,
                );
            }
        }

        entries
    }

    /// Generate all JEs from an O2C document chain.
    pub fn generate_from_o2c_chain(&mut self, chain: &O2CDocumentChain) -> Vec<JournalEntry> {
        let mut entries = Vec::new();

        // Generate JEs for deliveries
        for delivery in &chain.deliveries {
            if let Some(je) = self.generate_from_delivery(delivery) {
                entries.push(je);
            }
        }

        // Generate JE for customer invoice
        if let Some(ref invoice) = chain.customer_invoice {
            if let Some(je) = self.generate_from_customer_invoice(invoice) {
                entries.push(je);
            }
        }

        // Generate JE for customer receipt
        if let Some(ref receipt) = chain.customer_receipt {
            if let Some(je) = self.generate_from_ar_receipt(receipt) {
                entries.push(je);
            }
        }

        // Generate JEs for remainder receipts (follow-up to partial payments)
        for receipt in &chain.remainder_receipts {
            if let Some(je) = self.generate_from_ar_receipt(receipt) {
                entries.push(je);
            }
        }

        // Apply lettrage on complete O2C chains (invoice + receipt both present)
        if self.config.populate_fec_fields && chain.customer_receipt.is_some() {
            if let Some(ref receipt) = chain.customer_receipt {
                let posting_date = receipt
                    .header
                    .posting_date
                    .unwrap_or(receipt.header.document_date);
                self.apply_lettrage(
                    &mut entries,
                    &chain.sales_order.header.document_id,
                    posting_date,
                );
            }
        }

        entries
    }

    /// Generate JE from Goods Receipt.
    /// DR Inventory, CR GR/IR Clearing
    pub fn generate_from_goods_receipt(&mut self, gr: &GoodsReceipt) -> Option<JournalEntry> {
        if gr.items.is_empty() {
            return None;
        }

        let document_id = self.uuid_factory.next();

        // Use the total_value from the GR, or calculate from line items
        let total_amount = if gr.total_value > Decimal::ZERO {
            gr.total_value
        } else {
            gr.items
                .iter()
                .map(|item| item.base.net_amount)
                .sum::<Decimal>()
        };

        if total_amount == Decimal::ZERO {
            return None;
        }

        // Use posting_date or fall back to document_date
        let posting_date = gr.header.posting_date.unwrap_or(gr.header.document_date);

        let mut header = JournalEntryHeader::with_deterministic_id(
            gr.header.company_code.clone(),
            posting_date,
            document_id,
        );
        header.source = TransactionSource::Automated;
        header.business_process = Some(BusinessProcess::P2P);
        header.reference = Some(format!("GR:{}", gr.header.document_id));
        header.header_text = Some(format!(
            "Goods Receipt {} - {}",
            gr.header.document_id,
            gr.vendor_id.as_deref().unwrap_or("Unknown")
        ));

        let mut entry = JournalEntry::new(header);

        // DR Inventory
        let debit_line = JournalEntryLine::debit(
            entry.header.document_id,
            1,
            self.config.inventory_account.clone(),
            total_amount,
        );
        entry.add_line(debit_line);

        // CR GR/IR Clearing
        let credit_line = JournalEntryLine::credit(
            entry.header.document_id,
            2,
            self.config.gr_ir_clearing_account.clone(),
            total_amount,
        );
        entry.add_line(credit_line);

        Some(entry)
    }

    /// Generate JE from Vendor Invoice.
    ///
    /// When the invoice carries tax (`tax_amount > 0`), the entry is split:
    /// - DR GR/IR Clearing = net amount
    /// - DR Input VAT      = tax amount
    /// - CR AP              = gross (payable) amount
    ///
    /// When there is no tax, the original two-line entry is produced:
    /// - DR GR/IR Clearing = payable amount
    /// - CR AP              = payable amount
    pub fn generate_from_vendor_invoice(
        &mut self,
        invoice: &VendorInvoice,
    ) -> Option<JournalEntry> {
        if invoice.payable_amount == Decimal::ZERO {
            return None;
        }

        let document_id = self.uuid_factory.next();

        // Use posting_date or fall back to document_date
        let posting_date = invoice
            .header
            .posting_date
            .unwrap_or(invoice.header.document_date);

        let mut header = JournalEntryHeader::with_deterministic_id(
            invoice.header.company_code.clone(),
            posting_date,
            document_id,
        );
        header.source = TransactionSource::Automated;
        header.business_process = Some(BusinessProcess::P2P);
        header.reference = Some(format!("VI:{}", invoice.header.document_id));
        header.header_text = Some(format!(
            "Vendor Invoice {} - {}",
            invoice.vendor_invoice_number, invoice.vendor_id
        ));

        let mut entry = JournalEntry::new(header);

        let has_vat = invoice.tax_amount > Decimal::ZERO;
        let clearing_amount = if has_vat {
            invoice.net_amount
        } else {
            invoice.payable_amount
        };

        // DR GR/IR Clearing (net amount when VAT present, else payable)
        let debit_line = JournalEntryLine::debit(
            entry.header.document_id,
            1,
            self.config.gr_ir_clearing_account.clone(),
            clearing_amount,
        );
        entry.add_line(debit_line);

        // DR Input VAT (only when tax is non-zero)
        if has_vat {
            let vat_line = JournalEntryLine::debit(
                entry.header.document_id,
                2,
                self.config.vat_input_account.clone(),
                invoice.tax_amount,
            );
            entry.add_line(vat_line);
        }

        // CR Accounts Payable (gross / payable amount)
        let mut credit_line = JournalEntryLine::credit(
            entry.header.document_id,
            if has_vat { 3 } else { 2 },
            self.config.ap_account.clone(),
            invoice.payable_amount,
        );
        self.set_auxiliary_fields(&mut credit_line, &invoice.vendor_id, &invoice.vendor_id);
        entry.add_line(credit_line);

        Some(entry)
    }

    /// Generate JE from AP Payment.
    /// DR AP, CR Cash
    pub fn generate_from_ap_payment(&mut self, payment: &Payment) -> Option<JournalEntry> {
        if payment.amount == Decimal::ZERO {
            return None;
        }

        let document_id = self.uuid_factory.next();

        // Use posting_date or fall back to document_date
        let posting_date = payment
            .header
            .posting_date
            .unwrap_or(payment.header.document_date);

        let mut header = JournalEntryHeader::with_deterministic_id(
            payment.header.company_code.clone(),
            posting_date,
            document_id,
        );
        header.source = TransactionSource::Automated;
        header.business_process = Some(BusinessProcess::P2P);
        header.reference = Some(format!("PAY:{}", payment.header.document_id));
        header.header_text = Some(format!(
            "Payment {} - {}",
            payment.header.document_id, payment.business_partner_id
        ));

        let mut entry = JournalEntry::new(header);

        // DR Accounts Payable
        let mut debit_line = JournalEntryLine::debit(
            entry.header.document_id,
            1,
            self.config.ap_account.clone(),
            payment.amount,
        );
        self.set_auxiliary_fields(
            &mut debit_line,
            &payment.business_partner_id,
            &payment.business_partner_id,
        );
        entry.add_line(debit_line);

        // CR Cash/Bank
        let credit_line = JournalEntryLine::credit(
            entry.header.document_id,
            2,
            self.config.cash_account.clone(),
            payment.amount,
        );
        entry.add_line(credit_line);

        Some(entry)
    }

    /// Generate JE from Delivery.
    /// DR COGS, CR Inventory
    pub fn generate_from_delivery(&mut self, delivery: &Delivery) -> Option<JournalEntry> {
        if delivery.items.is_empty() {
            return None;
        }

        let document_id = self.uuid_factory.next();

        // Calculate total cost from line items
        let total_cost = delivery
            .items
            .iter()
            .map(|item| item.base.net_amount)
            .sum::<Decimal>();

        if total_cost == Decimal::ZERO {
            return None;
        }

        // Use posting_date or fall back to document_date
        let posting_date = delivery
            .header
            .posting_date
            .unwrap_or(delivery.header.document_date);

        let mut header = JournalEntryHeader::with_deterministic_id(
            delivery.header.company_code.clone(),
            posting_date,
            document_id,
        );
        header.source = TransactionSource::Automated;
        header.business_process = Some(BusinessProcess::O2C);
        header.reference = Some(format!("DEL:{}", delivery.header.document_id));
        header.header_text = Some(format!(
            "Delivery {} - {}",
            delivery.header.document_id, delivery.customer_id
        ));

        let mut entry = JournalEntry::new(header);

        // DR COGS
        let debit_line = JournalEntryLine::debit(
            entry.header.document_id,
            1,
            self.config.cogs_account.clone(),
            total_cost,
        );
        entry.add_line(debit_line);

        // CR Inventory
        let credit_line = JournalEntryLine::credit(
            entry.header.document_id,
            2,
            self.config.inventory_account.clone(),
            total_cost,
        );
        entry.add_line(credit_line);

        Some(entry)
    }

    /// Generate JE from Customer Invoice.
    ///
    /// When the invoice carries tax (`total_tax_amount > 0`), the entry is split:
    /// - DR AR          = gross amount
    /// - CR Revenue     = net amount
    /// - CR VAT Payable = tax amount
    ///
    /// When there is no tax, the original two-line entry is produced:
    /// - DR AR      = gross amount
    /// - CR Revenue = gross amount
    pub fn generate_from_customer_invoice(
        &mut self,
        invoice: &CustomerInvoice,
    ) -> Option<JournalEntry> {
        if invoice.total_gross_amount == Decimal::ZERO {
            return None;
        }

        let document_id = self.uuid_factory.next();

        // Use posting_date or fall back to document_date
        let posting_date = invoice
            .header
            .posting_date
            .unwrap_or(invoice.header.document_date);

        let mut header = JournalEntryHeader::with_deterministic_id(
            invoice.header.company_code.clone(),
            posting_date,
            document_id,
        );
        header.source = TransactionSource::Automated;
        header.business_process = Some(BusinessProcess::O2C);
        header.reference = Some(format!("CI:{}", invoice.header.document_id));
        header.header_text = Some(format!(
            "Customer Invoice {} - {}",
            invoice.header.document_id, invoice.customer_id
        ));

        let mut entry = JournalEntry::new(header);

        // DR Accounts Receivable (gross amount)
        let mut debit_line = JournalEntryLine::debit(
            entry.header.document_id,
            1,
            self.config.ar_account.clone(),
            invoice.total_gross_amount,
        );
        self.set_auxiliary_fields(&mut debit_line, &invoice.customer_id, &invoice.customer_id);
        entry.add_line(debit_line);

        // CR Revenue (net amount when VAT present, else gross)
        let revenue_amount = if invoice.total_tax_amount > Decimal::ZERO {
            invoice.total_net_amount
        } else {
            invoice.total_gross_amount
        };
        let credit_line = JournalEntryLine::credit(
            entry.header.document_id,
            2,
            self.config.revenue_account.clone(),
            revenue_amount,
        );
        entry.add_line(credit_line);

        // CR VAT Payable (only when tax is non-zero)
        if invoice.total_tax_amount > Decimal::ZERO {
            let vat_line = JournalEntryLine::credit(
                entry.header.document_id,
                3,
                self.config.vat_output_account.clone(),
                invoice.total_tax_amount,
            );
            entry.add_line(vat_line);
        }

        Some(entry)
    }

    /// Generate JE from AR Receipt (Customer Payment).
    /// DR Cash, CR AR
    pub fn generate_from_ar_receipt(&mut self, payment: &Payment) -> Option<JournalEntry> {
        if payment.amount == Decimal::ZERO {
            return None;
        }

        let document_id = self.uuid_factory.next();

        // Use posting_date or fall back to document_date
        let posting_date = payment
            .header
            .posting_date
            .unwrap_or(payment.header.document_date);

        let mut header = JournalEntryHeader::with_deterministic_id(
            payment.header.company_code.clone(),
            posting_date,
            document_id,
        );
        header.source = TransactionSource::Automated;
        header.business_process = Some(BusinessProcess::O2C);
        header.reference = Some(format!("RCP:{}", payment.header.document_id));
        header.header_text = Some(format!(
            "Customer Receipt {} - {}",
            payment.header.document_id, payment.business_partner_id
        ));

        let mut entry = JournalEntry::new(header);

        // DR Cash/Bank
        let debit_line = JournalEntryLine::debit(
            entry.header.document_id,
            1,
            self.config.cash_account.clone(),
            payment.amount,
        );
        entry.add_line(debit_line);

        // CR Accounts Receivable
        let mut credit_line = JournalEntryLine::credit(
            entry.header.document_id,
            2,
            self.config.ar_account.clone(),
            payment.amount,
        );
        self.set_auxiliary_fields(
            &mut credit_line,
            &payment.business_partner_id,
            &payment.business_partner_id,
        );
        entry.add_line(credit_line);

        Some(entry)
    }
}

impl Default for DocumentFlowJeGenerator {
    fn default() -> Self {
        Self::new()
    }
}

#[cfg(test)]
#[allow(clippy::unwrap_used)]
mod tests {
    use super::*;
    use chrono::NaiveDate;
    use datasynth_core::models::documents::{GoodsReceiptItem, MovementType};

    fn create_test_gr() -> GoodsReceipt {
        let mut gr = GoodsReceipt::from_purchase_order(
            "GR-001".to_string(),
            "1000",
            "PO-001",
            "V-001",
            "P1000",
            "0001",
            2024,
            1,
            NaiveDate::from_ymd_opt(2024, 1, 15).unwrap(),
            "JSMITH",
        );

        let item = GoodsReceiptItem::from_po(
            10,
            "Test Material",
            Decimal::from(100),
            Decimal::from(50),
            "PO-001",
            10,
        )
        .with_movement_type(MovementType::GrForPo);

        gr.add_item(item);
        gr.post("JSMITH", NaiveDate::from_ymd_opt(2024, 1, 15).unwrap());

        gr
    }

    fn create_test_vendor_invoice() -> VendorInvoice {
        use datasynth_core::models::documents::VendorInvoiceItem;

        let mut invoice = VendorInvoice::new(
            "VI-001".to_string(),
            "1000",
            "V-001",
            "INV-12345".to_string(),
            2024,
            1,
            NaiveDate::from_ymd_opt(2024, 1, 20).unwrap(),
            "JSMITH",
        );

        let item = VendorInvoiceItem::from_po_gr(
            10,
            "Test Material",
            Decimal::from(100),
            Decimal::from(50),
            "PO-001",
            10,
            Some("GR-001".to_string()),
            Some(10),
        );

        invoice.add_item(item);
        invoice.post("JSMITH", NaiveDate::from_ymd_opt(2024, 1, 20).unwrap());

        invoice
    }

    fn create_test_payment() -> Payment {
        let mut payment = Payment::new_ap_payment(
            "PAY-001".to_string(),
            "1000",
            "V-001",
            Decimal::from(5000),
            2024,
            2,
            NaiveDate::from_ymd_opt(2024, 2, 15).unwrap(),
            "JSMITH",
        );

        payment.post("JSMITH", NaiveDate::from_ymd_opt(2024, 2, 15).unwrap());

        payment
    }

    #[test]
    fn test_generate_from_goods_receipt() {
        let mut generator = DocumentFlowJeGenerator::new();
        let gr = create_test_gr();

        let je = generator.generate_from_goods_receipt(&gr);

        assert!(je.is_some());
        let je = je.unwrap();

        // Should be balanced
        assert!(je.is_balanced());

        // Should have 2 lines
        assert_eq!(je.line_count(), 2);

        // DR should be inventory, CR should be GR/IR
        assert!(je.total_debit() > Decimal::ZERO);
        assert_eq!(je.total_debit(), je.total_credit());

        // Should reference source document
        assert!(je.header.reference.is_some());
        assert!(je.header.reference.as_ref().unwrap().contains("GR:"));
    }

    #[test]
    fn test_generate_from_vendor_invoice() {
        let mut generator = DocumentFlowJeGenerator::new();
        let invoice = create_test_vendor_invoice();

        let je = generator.generate_from_vendor_invoice(&invoice);

        assert!(je.is_some());
        let je = je.unwrap();

        assert!(je.is_balanced());
        assert_eq!(je.line_count(), 2);
        assert!(je.header.reference.as_ref().unwrap().contains("VI:"));
    }

    #[test]
    fn test_generate_from_ap_payment() {
        let mut generator = DocumentFlowJeGenerator::new();
        let payment = create_test_payment();

        let je = generator.generate_from_ap_payment(&payment);

        assert!(je.is_some());
        let je = je.unwrap();

        assert!(je.is_balanced());
        assert_eq!(je.line_count(), 2);
        assert!(je.header.reference.as_ref().unwrap().contains("PAY:"));
    }

    #[test]
    fn test_all_entries_are_balanced() {
        let mut generator = DocumentFlowJeGenerator::new();

        let gr = create_test_gr();
        let invoice = create_test_vendor_invoice();
        let payment = create_test_payment();

        let entries = vec![
            generator.generate_from_goods_receipt(&gr),
            generator.generate_from_vendor_invoice(&invoice),
            generator.generate_from_ap_payment(&payment),
        ];

        for entry in entries.into_iter().flatten() {
            assert!(
                entry.is_balanced(),
                "Entry {} is not balanced",
                entry.header.document_id
            );
        }
    }

    // ====================================================================
    // FEC compliance tests
    // ====================================================================

    #[test]
    fn test_french_gaap_auxiliary_on_ap_ar_lines_only() {
        // French GAAP config sets auxiliary fields on AP/AR lines only
        let mut generator =
            DocumentFlowJeGenerator::with_config_and_seed(DocumentFlowJeConfig::french_gaap(), 42);

        // Vendor invoice: AP line should have auxiliary, GR/IR line should not
        let invoice = create_test_vendor_invoice();
        let je = generator.generate_from_vendor_invoice(&invoice).unwrap();

        // Line 1 = DR GR/IR Clearing → no auxiliary
        assert!(
            je.lines[0].auxiliary_account_number.is_none(),
            "GR/IR clearing line should not have auxiliary"
        );

        // Line 2 = CR AP → has auxiliary
        assert_eq!(
            je.lines[1].auxiliary_account_number.as_deref(),
            Some("V-001"),
            "AP line should have vendor ID as auxiliary"
        );
        assert_eq!(
            je.lines[1].auxiliary_account_label.as_deref(),
            Some("V-001"),
        );
    }

    #[test]
    fn test_french_gaap_lettrage_on_complete_p2p_chain() {
        use datasynth_core::models::documents::PurchaseOrder;

        let mut generator =
            DocumentFlowJeGenerator::with_config_and_seed(DocumentFlowJeConfig::french_gaap(), 42);

        let po = PurchaseOrder::new(
            "PO-001",
            "1000",
            "V-001",
            2024,
            1,
            NaiveDate::from_ymd_opt(2024, 1, 10).unwrap(),
            "JSMITH",
        );

        let chain = P2PDocumentChain {
            purchase_order: po,
            goods_receipts: vec![create_test_gr()],
            vendor_invoice: Some(create_test_vendor_invoice()),
            payment: Some(create_test_payment()),
            remainder_payments: Vec::new(),
            is_complete: true,
            three_way_match_passed: true,
            payment_timing: None,
        };

        let entries = generator.generate_from_p2p_chain(&chain);
        assert!(!entries.is_empty());

        // All AP lines should share the same lettrage code
        let ap_account = &generator.config.ap_account;
        let mut lettrage_codes: Vec<&str> = Vec::new();
        for entry in &entries {
            for line in &entry.lines {
                if &line.gl_account == ap_account {
                    assert!(
                        line.lettrage.is_some(),
                        "AP line should have lettrage on complete chain"
                    );
                    assert!(line.lettrage_date.is_some());
                    lettrage_codes.push(line.lettrage.as_deref().unwrap());
                } else {
                    assert!(
                        line.lettrage.is_none(),
                        "Non-AP line should not have lettrage"
                    );
                }
            }
        }

        // All AP lettrage codes should be the same
        assert!(!lettrage_codes.is_empty());
        assert!(
            lettrage_codes.iter().all(|c| *c == lettrage_codes[0]),
            "All AP lines should share the same lettrage code"
        );
        assert!(lettrage_codes[0].starts_with("LTR-"));
    }

    #[test]
    fn test_incomplete_chain_has_no_lettrage() {
        use datasynth_core::models::documents::PurchaseOrder;

        let mut generator =
            DocumentFlowJeGenerator::with_config_and_seed(DocumentFlowJeConfig::french_gaap(), 42);

        let po = PurchaseOrder::new(
            "PO-002",
            "1000",
            "V-001",
            2024,
            1,
            NaiveDate::from_ymd_opt(2024, 1, 10).unwrap(),
            "JSMITH",
        );

        // Incomplete chain: no payment
        let chain = P2PDocumentChain {
            purchase_order: po,
            goods_receipts: vec![create_test_gr()],
            vendor_invoice: Some(create_test_vendor_invoice()),
            payment: None,
            remainder_payments: Vec::new(),
            is_complete: false,
            three_way_match_passed: false,
            payment_timing: None,
        };

        let entries = generator.generate_from_p2p_chain(&chain);

        for entry in &entries {
            for line in &entry.lines {
                assert!(
                    line.lettrage.is_none(),
                    "Incomplete chain should have no lettrage"
                );
            }
        }
    }

    #[test]
    fn test_default_config_no_fec_fields() {
        // Default config (non-French) should leave all FEC fields as None
        let mut generator = DocumentFlowJeGenerator::new();

        let invoice = create_test_vendor_invoice();
        let je = generator.generate_from_vendor_invoice(&invoice).unwrap();

        for line in &je.lines {
            assert!(line.auxiliary_account_number.is_none());
            assert!(line.auxiliary_account_label.is_none());
            assert!(line.lettrage.is_none());
            assert!(line.lettrage_date.is_none());
        }
    }

    #[test]
    fn test_auxiliary_lookup_uses_gl_account_instead_of_partner_id() {
        // When auxiliary lookup is populated, FEC auxiliary_account_number should
        // use the framework-specific GL account instead of the raw partner ID.
        let mut generator =
            DocumentFlowJeGenerator::with_config_and_seed(DocumentFlowJeConfig::french_gaap(), 42);

        let mut lookup = HashMap::new();
        lookup.insert("V-001".to_string(), "4010001".to_string());
        generator.set_auxiliary_account_lookup(lookup);

        let invoice = create_test_vendor_invoice();
        let je = generator.generate_from_vendor_invoice(&invoice).unwrap();

        // AP line should use the auxiliary GL account from lookup, not "V-001"
        assert_eq!(
            je.lines[1].auxiliary_account_number.as_deref(),
            Some("4010001"),
            "AP line should use auxiliary GL account from lookup"
        );
        // Label should still be the partner ID (human-readable)
        assert_eq!(
            je.lines[1].auxiliary_account_label.as_deref(),
            Some("V-001"),
        );
    }

    #[test]
    fn test_auxiliary_lookup_fallback_to_partner_id() {
        // When the auxiliary lookup exists but doesn't contain the partner,
        // should fall back to raw partner ID.
        let mut generator =
            DocumentFlowJeGenerator::with_config_and_seed(DocumentFlowJeConfig::french_gaap(), 42);

        // Lookup has a different vendor, not V-001
        let mut lookup = HashMap::new();
        lookup.insert("V-999".to_string(), "4019999".to_string());
        generator.set_auxiliary_account_lookup(lookup);

        let invoice = create_test_vendor_invoice();
        let je = generator.generate_from_vendor_invoice(&invoice).unwrap();

        // V-001 not in lookup, so should fall back to raw partner ID
        assert_eq!(
            je.lines[1].auxiliary_account_number.as_deref(),
            Some("V-001"),
            "Should fall back to partner ID when not in lookup"
        );
    }

    #[test]
    fn test_auxiliary_lookup_works_for_customer_receipt() {
        // Verify the lookup also works for O2C AR receipt lines.
        let mut generator =
            DocumentFlowJeGenerator::with_config_and_seed(DocumentFlowJeConfig::french_gaap(), 42);

        let mut lookup = HashMap::new();
        lookup.insert("C-001".to_string(), "4110001".to_string());
        generator.set_auxiliary_account_lookup(lookup);

        let mut receipt = Payment::new_ar_receipt(
            "RCP-001".to_string(),
            "1000",
            "C-001",
            Decimal::from(3000),
            2024,
            3,
            NaiveDate::from_ymd_opt(2024, 3, 15).unwrap(),
            "JSMITH",
        );
        receipt.post("JSMITH", NaiveDate::from_ymd_opt(2024, 3, 15).unwrap());

        let je = generator.generate_from_ar_receipt(&receipt).unwrap();

        // AR line (line 2 = CR AR) should use the auxiliary GL account from lookup
        assert_eq!(
            je.lines[1].auxiliary_account_number.as_deref(),
            Some("4110001"),
            "AR line should use auxiliary GL account from lookup"
        );
    }

    // ====================================================================
    // VAT / tax splitting tests
    // ====================================================================

    /// Helper: create a customer invoice with tax on its line items.
    fn create_test_customer_invoice_with_tax() -> CustomerInvoice {
        use datasynth_core::models::documents::CustomerInvoiceItem;

        let mut invoice = CustomerInvoice::new(
            "CI-001",
            "1000",
            "C-001",
            2024,
            1,
            NaiveDate::from_ymd_opt(2024, 1, 15).unwrap(),
            NaiveDate::from_ymd_opt(2024, 2, 14).unwrap(),
            "JSMITH",
        );

        // 10 units * 100 = 1000 net, 100 tax => 1100 gross
        let mut item =
            CustomerInvoiceItem::new(1, "Product A", Decimal::from(10), Decimal::from(100));
        item.base.tax_amount = Decimal::from(100);
        invoice.add_item(item);
        invoice.post("JSMITH", NaiveDate::from_ymd_opt(2024, 1, 15).unwrap());

        invoice
    }

    /// Helper: create a customer invoice without any tax.
    fn create_test_customer_invoice_no_tax() -> CustomerInvoice {
        use datasynth_core::models::documents::CustomerInvoiceItem;

        let mut invoice = CustomerInvoice::new(
            "CI-002",
            "1000",
            "C-002",
            2024,
            1,
            NaiveDate::from_ymd_opt(2024, 1, 15).unwrap(),
            NaiveDate::from_ymd_opt(2024, 2, 14).unwrap(),
            "JSMITH",
        );

        let item = CustomerInvoiceItem::new(1, "Product B", Decimal::from(10), Decimal::from(100));
        invoice.add_item(item);
        invoice.post("JSMITH", NaiveDate::from_ymd_opt(2024, 1, 15).unwrap());

        invoice
    }

    /// Helper: create a vendor invoice with tax on its line items.
    fn create_test_vendor_invoice_with_tax() -> VendorInvoice {
        use datasynth_core::models::documents::VendorInvoiceItem;

        let mut invoice = VendorInvoice::new(
            "VI-002".to_string(),
            "1000",
            "V-001",
            "INV-TAX-001".to_string(),
            2024,
            1,
            NaiveDate::from_ymd_opt(2024, 1, 20).unwrap(),
            "JSMITH",
        );

        // 100 qty * 50 price = 5000 net, 500 tax => 5500 gross = payable
        let item = VendorInvoiceItem::from_po_gr(
            10,
            "Test Material",
            Decimal::from(100),
            Decimal::from(50),
            "PO-001",
            10,
            Some("GR-001".to_string()),
            Some(10),
        )
        .with_tax("VAT10", Decimal::from(500));

        invoice.add_item(item);
        invoice.post("JSMITH", NaiveDate::from_ymd_opt(2024, 1, 20).unwrap());

        invoice
    }

    #[test]
    fn test_customer_invoice_with_tax_produces_three_lines() {
        let mut generator = DocumentFlowJeGenerator::new();
        let invoice = create_test_customer_invoice_with_tax();

        assert_eq!(invoice.total_net_amount, Decimal::from(1000));
        assert_eq!(invoice.total_tax_amount, Decimal::from(100));
        assert_eq!(invoice.total_gross_amount, Decimal::from(1100));

        let je = generator.generate_from_customer_invoice(&invoice).unwrap();

        // Should have 3 lines: DR AR, CR Revenue, CR VAT
        assert_eq!(
            je.line_count(),
            3,
            "Expected 3 JE lines for invoice with tax"
        );
        assert!(je.is_balanced(), "Entry must be balanced");

        // Line 1: DR AR = gross (1100)
        assert_eq!(je.lines[0].gl_account, control_accounts::AR_CONTROL);
        assert_eq!(je.lines[0].debit_amount, Decimal::from(1100));
        assert_eq!(je.lines[0].credit_amount, Decimal::ZERO);

        // Line 2: CR Revenue = net (1000)
        assert_eq!(je.lines[1].gl_account, revenue_accounts::PRODUCT_REVENUE);
        assert_eq!(je.lines[1].credit_amount, Decimal::from(1000));
        assert_eq!(je.lines[1].debit_amount, Decimal::ZERO);

        // Line 3: CR VAT Payable = tax (100)
        assert_eq!(je.lines[2].gl_account, tax_accounts::VAT_PAYABLE);
        assert_eq!(je.lines[2].credit_amount, Decimal::from(100));
        assert_eq!(je.lines[2].debit_amount, Decimal::ZERO);
    }

    #[test]
    fn test_customer_invoice_no_tax_produces_two_lines() {
        let mut generator = DocumentFlowJeGenerator::new();
        let invoice = create_test_customer_invoice_no_tax();

        assert_eq!(invoice.total_tax_amount, Decimal::ZERO);
        assert_eq!(invoice.total_net_amount, Decimal::from(1000));
        assert_eq!(invoice.total_gross_amount, Decimal::from(1000));

        let je = generator.generate_from_customer_invoice(&invoice).unwrap();

        // Should have 2 lines (no VAT line)
        assert_eq!(
            je.line_count(),
            2,
            "Expected 2 JE lines for invoice without tax"
        );
        assert!(je.is_balanced(), "Entry must be balanced");

        // Line 1: DR AR = gross (1000)
        assert_eq!(je.lines[0].gl_account, control_accounts::AR_CONTROL);
        assert_eq!(je.lines[0].debit_amount, Decimal::from(1000));

        // Line 2: CR Revenue = gross (1000)  — same as gross when no tax
        assert_eq!(je.lines[1].gl_account, revenue_accounts::PRODUCT_REVENUE);
        assert_eq!(je.lines[1].credit_amount, Decimal::from(1000));
    }

    #[test]
    fn test_vendor_invoice_with_tax_produces_three_lines() {
        let mut generator = DocumentFlowJeGenerator::new();
        let invoice = create_test_vendor_invoice_with_tax();

        assert_eq!(invoice.net_amount, Decimal::from(5000));
        assert_eq!(invoice.tax_amount, Decimal::from(500));
        assert_eq!(invoice.gross_amount, Decimal::from(5500));
        assert_eq!(invoice.payable_amount, Decimal::from(5500));

        let je = generator.generate_from_vendor_invoice(&invoice).unwrap();

        // Should have 3 lines: DR GR/IR, DR Input VAT, CR AP
        assert_eq!(
            je.line_count(),
            3,
            "Expected 3 JE lines for vendor invoice with tax"
        );
        assert!(je.is_balanced(), "Entry must be balanced");

        // Line 1: DR GR/IR Clearing = net (5000)
        assert_eq!(je.lines[0].gl_account, control_accounts::GR_IR_CLEARING);
        assert_eq!(je.lines[0].debit_amount, Decimal::from(5000));
        assert_eq!(je.lines[0].credit_amount, Decimal::ZERO);

        // Line 2: DR Input VAT = tax (500)
        assert_eq!(je.lines[1].gl_account, tax_accounts::INPUT_VAT);
        assert_eq!(je.lines[1].debit_amount, Decimal::from(500));
        assert_eq!(je.lines[1].credit_amount, Decimal::ZERO);

        // Line 3: CR AP = gross (5500)
        assert_eq!(je.lines[2].gl_account, control_accounts::AP_CONTROL);
        assert_eq!(je.lines[2].credit_amount, Decimal::from(5500));
        assert_eq!(je.lines[2].debit_amount, Decimal::ZERO);
    }

    #[test]
    fn test_vendor_invoice_no_tax_produces_two_lines() {
        // The existing create_test_vendor_invoice() has no tax
        let mut generator = DocumentFlowJeGenerator::new();
        let invoice = create_test_vendor_invoice();

        assert_eq!(invoice.tax_amount, Decimal::ZERO);

        let je = generator.generate_from_vendor_invoice(&invoice).unwrap();

        // Should have 2 lines (unchanged behavior)
        assert_eq!(
            je.line_count(),
            2,
            "Expected 2 JE lines for vendor invoice without tax"
        );
        assert!(je.is_balanced(), "Entry must be balanced");

        // Line 1: DR GR/IR Clearing = payable
        assert_eq!(je.lines[0].gl_account, control_accounts::GR_IR_CLEARING);
        assert_eq!(je.lines[0].debit_amount, invoice.payable_amount);

        // Line 2: CR AP = payable
        assert_eq!(je.lines[1].gl_account, control_accounts::AP_CONTROL);
        assert_eq!(je.lines[1].credit_amount, invoice.payable_amount);
    }

    #[test]
    fn test_vat_accounts_configurable() {
        // Verify that VAT accounts can be customized via config
        let mut config = DocumentFlowJeConfig::default();
        config.vat_output_account = "2999".to_string();
        config.vat_input_account = "1999".to_string();

        let mut generator = DocumentFlowJeGenerator::with_config_and_seed(config, 42);

        // Customer invoice with tax
        let ci = create_test_customer_invoice_with_tax();
        let je = generator.generate_from_customer_invoice(&ci).unwrap();
        assert_eq!(
            je.lines[2].gl_account, "2999",
            "VAT output account should be configurable"
        );

        // Vendor invoice with tax
        let vi = create_test_vendor_invoice_with_tax();
        let je = generator.generate_from_vendor_invoice(&vi).unwrap();
        assert_eq!(
            je.lines[1].gl_account, "1999",
            "VAT input account should be configurable"
        );
    }

    #[test]
    fn test_vat_entries_from_framework_accounts() {
        // FrameworkAccounts should propagate VAT accounts into DocumentFlowJeConfig
        let fa = datasynth_core::FrameworkAccounts::us_gaap();
        let config = DocumentFlowJeConfig::from(&fa);

        assert_eq!(config.vat_output_account, tax_accounts::VAT_PAYABLE);
        assert_eq!(config.vat_input_account, tax_accounts::INPUT_VAT);

        let fa_fr = datasynth_core::FrameworkAccounts::french_gaap();
        let config_fr = DocumentFlowJeConfig::from(&fa_fr);

        assert_eq!(config_fr.vat_output_account, "445710");
        assert_eq!(config_fr.vat_input_account, "445660");
    }

    #[test]
    fn test_french_gaap_vat_accounts() {
        let config = DocumentFlowJeConfig::french_gaap();
        assert_eq!(config.vat_output_account, "445710"); // PCG OUTPUT_VAT
        assert_eq!(config.vat_input_account, "445660"); // PCG INPUT_VAT
    }

    #[test]
    fn test_vat_balanced_with_multiple_items() {
        // Multiple line items with different tax amounts must still balance
        use datasynth_core::models::documents::CustomerInvoiceItem;

        let mut invoice = CustomerInvoice::new(
            "CI-003",
            "1000",
            "C-003",
            2024,
            1,
            NaiveDate::from_ymd_opt(2024, 1, 15).unwrap(),
            NaiveDate::from_ymd_opt(2024, 2, 14).unwrap(),
            "JSMITH",
        );

        // Item 1: 500 net, 50 tax
        let mut item1 = CustomerInvoiceItem::new(1, "A", Decimal::from(5), Decimal::from(100));
        item1.base.tax_amount = Decimal::from(50);
        invoice.add_item(item1);

        // Item 2: 300 net, 30 tax
        let mut item2 = CustomerInvoiceItem::new(2, "B", Decimal::from(3), Decimal::from(100));
        item2.base.tax_amount = Decimal::from(30);
        invoice.add_item(item2);

        invoice.post("JSMITH", NaiveDate::from_ymd_opt(2024, 1, 15).unwrap());

        // net=800, tax=80, gross=880
        assert_eq!(invoice.total_net_amount, Decimal::from(800));
        assert_eq!(invoice.total_tax_amount, Decimal::from(80));
        assert_eq!(invoice.total_gross_amount, Decimal::from(880));

        let mut generator = DocumentFlowJeGenerator::new();
        let je = generator.generate_from_customer_invoice(&invoice).unwrap();

        assert_eq!(je.line_count(), 3);
        assert!(je.is_balanced());
        assert_eq!(je.total_debit(), Decimal::from(880));
        assert_eq!(je.total_credit(), Decimal::from(880));
    }
}