package handlers

import (
	"database/sql"
	"encoding/json"
	"net/http"
	"time"

	"github.com/go-chi/chi/v5"
)

type LegalHandler struct {
	DB *sql.DB
}

func NewLegalHandler(db *sql.DB) *LegalHandler {
	return &LegalHandler{DB: db}
}

type Contract struct {
	ID           string     `json:"id"`
	Title        string     `json:"title"`
	Counterparty string     `json:"counterparty"`
	Type         string     `json:"type"`
	Status       string     `json:"status"`
	Value        float64    `json:"value"`
	Currency     string     `json:"currency"`
	StartDate    *time.Time `json:"start_date"`
	EndDate      *time.Time `json:"end_date"`
	RenewalDate  *time.Time `json:"renewal_date"`
	DocumentURL  string     `json:"document_url"`
	CreatedAt    time.Time  `json:"created_at"`
}

type ContractReminder struct {
	ID         string    `json:"id"`
	ContractID string    `json:"contract_id"`
	Type       string    `json:"type"`
	DueDate    time.Time `json:"due_date"`
	Status     string    `json:"status"`
}

func (h *LegalHandler) ListContracts(w http.ResponseWriter, r *http.Request) {
	status := r.URL.Query().Get("status")
	if status == "" {
		status = "active"
	}

	rows, err := h.DB.Query(`
		SELECT id, title, counterparty, type, status, value, currency,
		       start_date, end_date, renewal_date, document_url, created_at
		FROM boc_contracts
		WHERE status = $1
		ORDER BY renewal_date ASC NULLS LAST
	`, status)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	contracts := []Contract{}
	for rows.Next() {
		var c Contract
		if err := rows.Scan(&c.ID, &c.Title, &c.Counterparty, &c.Type, &c.Status,
			&c.Value, &c.Currency, &c.StartDate, &c.EndDate, &c.RenewalDate,
			&c.DocumentURL, &c.CreatedAt); err != nil {
			continue
		}
		contracts = append(contracts, c)
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"contracts": contracts,
		"total":     len(contracts),
	})
}

func (h *LegalHandler) CreateContract(w http.ResponseWriter, r *http.Request) {
	var req Contract
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request")
		return
	}

	var id string
	err := h.DB.QueryRow(`
		INSERT INTO boc_contracts (title, counterparty, type, status, value, currency,
		                           start_date, end_date, renewal_date, document_url)
		VALUES ($1, $2, $3, 'draft', $4, $5, $6, $7, $8, $9)
		RETURNING id
	`, req.Title, req.Counterparty, req.Type, req.Value, req.Currency,
		req.StartDate, req.EndDate, req.RenewalDate, req.DocumentURL).Scan(&id)

	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to create contract")
		return
	}

	// Create reminder if renewal date is set
	if req.RenewalDate != nil {
		reminderDate := req.RenewalDate.AddDate(0, 0, -30) // 30 days before
		h.DB.Exec(`
			INSERT INTO boc_contract_reminders (contract_id, type, due_date, status)
			VALUES ($1, 'renewal', $2, 'pending')
		`, id, reminderDate)
	}

	writeJSON(w, http.StatusCreated, map[string]interface{}{
		"id":      id,
		"message": "Contract created",
	})
}

func (h *LegalHandler) GetContract(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	var c Contract
	err := h.DB.QueryRow(`
		SELECT id, title, counterparty, type, status, value, currency,
		       start_date, end_date, renewal_date, document_url, created_at
		FROM boc_contracts WHERE id = $1
	`, id).Scan(&c.ID, &c.Title, &c.Counterparty, &c.Type, &c.Status,
		&c.Value, &c.Currency, &c.StartDate, &c.EndDate, &c.RenewalDate,
		&c.DocumentURL, &c.CreatedAt)

	if err == sql.ErrNoRows {
		writeError(w, http.StatusNotFound, "contract not found")
		return
	}
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}

	writeJSON(w, http.StatusOK, c)
}

func (h *LegalHandler) UpdateContract(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	var req Contract
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request")
		return
	}

	_, err := h.DB.Exec(`
		UPDATE boc_contracts
		SET title = $1, counterparty = $2, type = $3, status = $4,
		    value = $5, currency = $6, start_date = $7, end_date = $8,
		    renewal_date = $9, document_url = $10
		WHERE id = $11
	`, req.Title, req.Counterparty, req.Type, req.Status, req.Value, req.Currency,
		req.StartDate, req.EndDate, req.RenewalDate, req.DocumentURL, id)

	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to update contract")
		return
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"message": "Contract updated",
	})
}

func (h *LegalHandler) ListReminders(w http.ResponseWriter, r *http.Request) {
	rows, err := h.DB.Query(`
		SELECT r.id, r.contract_id, r.type, r.due_date, r.status,
		       c.title as contract_title
		FROM boc_contract_reminders r
		JOIN boc_contracts c ON r.contract_id = c.id
		WHERE r.status = 'pending'
		ORDER BY r.due_date ASC
		LIMIT 50
	`)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	reminders := []map[string]interface{}{}
	for rows.Next() {
		var id, contractID, reminderType, status, contractTitle string
		var dueDate time.Time
		if err := rows.Scan(&id, &contractID, &reminderType, &dueDate, &status, &contractTitle); err != nil {
			continue
		}
		reminders = append(reminders, map[string]interface{}{
			"id":             id,
			"contract_id":    contractID,
			"contract_title": contractTitle,
			"type":           reminderType,
			"due_date":       dueDate,
			"status":         status,
		})
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"reminders": reminders,
		"total":     len(reminders),
	})
}