package handlers

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

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

type HRHandler struct {
	DB *sql.DB
}

func NewHRHandler(db *sql.DB) *HRHandler {
	return &HRHandler{DB: db}
}

type Employee struct {
	ID             string          `json:"id"`
	FirstName      string          `json:"first_name"`
	LastName       string          `json:"last_name"`
	Email          string          `json:"email"`
	Phone          string          `json:"phone"`
	Department     string          `json:"department"`
	Position       string          `json:"position"`
	EmploymentType string          `json:"employment_type"`
	Salary         float64         `json:"salary"`
	Currency       string          `json:"currency"`
	StartDate      *time.Time      `json:"start_date"`
	Status         string          `json:"status"`
	CreatedAt      time.Time       `json:"created_at"`
}

type Leave struct {
	ID          string     `json:"id"`
	EmployeeID  string     `json:"employee_id"`
	Type        string     `json:"type"`
	StartDate   time.Time  `json:"start_date"`
	EndDate     time.Time  `json:"end_date"`
	Days        float64    `json:"days"`
	Status      string     `json:"status"`
	ApprovedBy  *string    `json:"approved_by"`
	ApprovedAt  *time.Time `json:"approved_at"`
}

type Timesheet struct {
	ID          string     `json:"id"`
	EmployeeID  string     `json:"employee_id"`
	Date        time.Time  `json:"date"`
	Hours       float64    `json:"hours"`
	Project     string     `json:"project"`
	Task        string     `json:"task"`
	Description string     `json:"description"`
	Status      string     `json:"status"`
}

func (h *HRHandler) ListEmployees(w http.ResponseWriter, r *http.Request) {
	rows, err := h.DB.Query(`
		SELECT id, first_name, last_name, email, phone, department, position, 
		       employment_type, salary, currency, start_date, status, created_at
		FROM boc_employees
		WHERE status = 'active'
		ORDER BY created_at DESC
	`)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	employees := []Employee{}
	for rows.Next() {
		var e Employee
		if err := rows.Scan(&e.ID, &e.FirstName, &e.LastName, &e.Email, &e.Phone,
			&e.Department, &e.Position, &e.EmploymentType, &e.Salary, &e.Currency,
			&e.StartDate, &e.Status, &e.CreatedAt); err != nil {
			continue
		}
		employees = append(employees, e)
	}

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

func (h *HRHandler) CreateEmployee(w http.ResponseWriter, r *http.Request) {
	var req Employee
	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_employees (first_name, last_name, email, phone, department, position, 
		                           employment_type, salary, currency, start_date, status)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, 'active')
		RETURNING id
	`, req.FirstName, req.LastName, req.Email, req.Phone, req.Department, req.Position,
		req.EmploymentType, req.Salary, req.Currency, req.StartDate).Scan(&id)

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

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

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

	var e Employee
	err := h.DB.QueryRow(`
		SELECT id, first_name, last_name, email, phone, department, position,
		       employment_type, salary, currency, start_date, status, created_at
		FROM boc_employees WHERE id = $1
	`, id).Scan(&e.ID, &e.FirstName, &e.LastName, &e.Email, &e.Phone,
		&e.Department, &e.Position, &e.EmploymentType, &e.Salary, &e.Currency,
		&e.StartDate, &e.Status, &e.CreatedAt)

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

	writeJSON(w, http.StatusOK, e)
}

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

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

	_, err := h.DB.Exec(`
		UPDATE boc_employees
		SET first_name = $1, last_name = $2, email = $3, phone = $4,
		    department = $5, position = $6, employment_type = $7,
		    salary = $8, currency = $9, start_date = $10, status = $11
		WHERE id = $12
	`, req.FirstName, req.LastName, req.Email, req.Phone, req.Department,
		req.Position, req.EmploymentType, req.Salary, req.Currency,
		req.StartDate, req.Status, id)

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

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

func (h *HRHandler) ListLeaves(w http.ResponseWriter, r *http.Request) {
	rows, err := h.DB.Query(`
		SELECT id, employee_id, type, start_date, end_date, days, status, approved_by, approved_at
		FROM boc_leaves
		ORDER BY start_date DESC
		LIMIT 100
	`)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	leaves := []Leave{}
	for rows.Next() {
		var l Leave
		if err := rows.Scan(&l.ID, &l.EmployeeID, &l.Type, &l.StartDate, &l.EndDate,
			&l.Days, &l.Status, &l.ApprovedBy, &l.ApprovedAt); err != nil {
			continue
		}
		leaves = append(leaves, l)
	}

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

func (h *HRHandler) CreateLeave(w http.ResponseWriter, r *http.Request) {
	var req Leave
	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_leaves (employee_id, type, start_date, end_date, days, status)
		VALUES ($1, $2, $3, $4, $5, 'pending')
		RETURNING id
	`, req.EmployeeID, req.Type, req.StartDate, req.EndDate, req.Days).Scan(&id)

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

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

func (h *HRHandler) ListTimesheets(w http.ResponseWriter, r *http.Request) {
	rows, err := h.DB.Query(`
		SELECT id, employee_id, date, hours, project, task, description, status
		FROM boc_timesheets
		ORDER BY date DESC
		LIMIT 100
	`)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	timesheets := []Timesheet{}
	for rows.Next() {
		var t Timesheet
		if err := rows.Scan(&t.ID, &t.EmployeeID, &t.Date, &t.Hours, &t.Project,
			&t.Task, &t.Description, &t.Status); err != nil {
			continue
		}
		timesheets = append(timesheets, t)
	}

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

func (h *HRHandler) CreateTimesheet(w http.ResponseWriter, r *http.Request) {
	var req Timesheet
	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_timesheets (employee_id, date, hours, project, task, description, status)
		VALUES ($1, $2, $3, $4, $5, $6, 'draft')
		RETURNING id
	`, req.EmployeeID, req.Date, req.Hours, req.Project, req.Task, req.Description).Scan(&id)

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

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