package handlers

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

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

type ProjectHandler struct {
	DB *sql.DB
}

func NewProjectHandler(db *sql.DB) *ProjectHandler {
	return &ProjectHandler{DB: db}
}

type Project struct {
	ID          string                 `json:"id"`
	Name        string                 `json:"name"`
	Description string                 `json:"description"`
	CustomerID  *string                `json:"customer_id"`
	Status      string                 `json:"status"`
	Budget      float64                `json:"budget"`
	Spent       float64                `json:"spent"`
	Currency    string                 `json:"currency"`
	StartDate   *time.Time             `json:"start_date"`
	EndDate     *time.Time             `json:"end_date"`
	ManagerID   *string                `json:"manager_id"`
	Progress    float64                `json:"progress"`
	CreatedAt   time.Time              `json:"created_at"`
}

type ProjectTime struct {
	ID          string    `json:"id"`
	ProjectID   string    `json:"project_id"`
	EmployeeID  string    `json:"employee_id"`
	EmployeeName string   `json:"employee_name"`
	Date        time.Time `json:"date"`
	Hours       float64   `json:"hours"`
	Description string    `json:"description"`
	Billable    bool      `json:"billable"`
	HourlyRate  float64   `json:"hourly_rate"`
}

func (h *ProjectHandler) ListProjects(w http.ResponseWriter, r *http.Request) {
	status := r.URL.Query().Get("status")
	if status == "" {
		status = "all"
	}

	var query string
	var args []interface{}
	if status == "all" {
		query = `SELECT id, name, description, customer_id, status, budget, spent, currency, start_date, end_date, manager_id, created_at FROM boc_projects ORDER BY created_at DESC LIMIT 100`
	} else {
		query = `SELECT id, name, description, customer_id, status, budget, spent, currency, start_date, end_date, manager_id, created_at FROM boc_projects WHERE status = $1 ORDER BY created_at DESC LIMIT 100`
		args = append(args, status)
	}

	rows, err := h.DB.Query(query, args...)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	projects := []Project{}
	for rows.Next() {
		var p Project
		if err := rows.Scan(&p.ID, &p.Name, &p.Description, &p.CustomerID, &p.Status, &p.Budget, &p.Spent, &p.Currency, &p.StartDate, &p.EndDate, &p.ManagerID, &p.CreatedAt); err != nil {
			continue
		}
		if p.Budget > 0 {
			p.Progress = (p.Spent / p.Budget) * 100
		}
		projects = append(projects, p)
	}

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

func (h *ProjectHandler) CreateProject(w http.ResponseWriter, r *http.Request) {
	var req Project
	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_projects (name, description, customer_id, status, budget, currency, start_date, end_date, manager_id)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
		RETURNING id
	`, req.Name, req.Description, req.CustomerID, req.Status, req.Budget, req.Currency, req.StartDate, req.EndDate, req.ManagerID).Scan(&id)

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

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

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

	var p Project
	err := h.DB.QueryRow(`
		SELECT id, name, description, customer_id, status, budget, spent, currency, start_date, end_date, manager_id, created_at
		FROM boc_projects WHERE id = $1
	`, id).Scan(&p.ID, &p.Name, &p.Description, &p.CustomerID, &p.Status, &p.Budget, &p.Spent, &p.Currency, &p.StartDate, &p.EndDate, &p.ManagerID, &p.CreatedAt)

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

	if p.Budget > 0 {
		p.Progress = (p.Spent / p.Budget) * 100
	}

	// Get time entries
	rows, err := h.DB.Query(`
		SELECT pt.id, pt.project_id, pt.employee_id, e.first_name || ' ' || e.last_name, pt.date, pt.hours, pt.description, pt.billable, pt.hourly_rate
		FROM boc_project_times pt
		JOIN boc_employees e ON pt.employee_id = e.id
		WHERE pt.project_id = $1
		ORDER BY pt.date DESC
	`, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	times := []ProjectTime{}
	for rows.Next() {
		var t ProjectTime
		if err := rows.Scan(&t.ID, &t.ProjectID, &t.EmployeeID, &t.EmployeeName, &t.Date, &t.Hours, &t.Description, &t.Billable, &t.HourlyRate); err != nil {
			continue
		}
		times = append(times, t)
	}

	// Get expenses
	expenseRows, err := h.DB.Query(`
		SELECT e.id, e.category, e.description, e.amount, e.created_at
		FROM boc_project_expenses pe
		JOIN boc_expenses e ON pe.expense_id = e.id
		WHERE pe.project_id = $1
	`, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer expenseRows.Close()

	expenses := []map[string]interface{}{}
	for expenseRows.Next() {
		var eID, category, description string
		var amount float64
		var createdAt time.Time
		if err := expenseRows.Scan(&eID, &category, &description, &amount, &createdAt); err != nil {
			continue
		}
		expenses = append(expenses, map[string]interface{}{
			"id":          eID,
			"category":    category,
			"description": description,
			"amount":      amount,
			"created_at":  createdAt,
		})
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"project":  p,
		"times":    times,
		"expenses": expenses,
	})
}

func (h *ProjectHandler) AddTime(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")

	var req ProjectTime
	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_project_times (project_id, employee_id, date, hours, description, billable, hourly_rate)
		VALUES ($1, $2, $3, $4, $5, $6, $7)
		RETURNING id
	`, projectID, req.EmployeeID, req.Date, req.Hours, req.Description, req.Billable, req.HourlyRate).Scan(&id)

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

	// Update project spent
	h.DB.Exec(`
		UPDATE boc_projects SET spent = (
			SELECT COALESCE(SUM(pt.hours * pt.hourly_rate), 0) + COALESCE(SUM(pe.amount), 0)
			FROM boc_project_times pt
			LEFT JOIN boc_project_expenses pe ON pe.project_id = pt.project_id
			WHERE pt.project_id = $1
		) WHERE id = $1
	`, projectID)

	writeJSON(w, http.StatusCreated, map[string]interface{}{
		"id":      id,
		"message": "Time entry added",
	})
}

func (h *ProjectHandler) GetProjectSummary(w http.ResponseWriter, r *http.Request) {
	// Summary across all projects
	var totalBudget, totalSpent float64
	err := h.DB.QueryRow(`
		SELECT COALESCE(SUM(budget), 0), COALESCE(SUM(spent), 0)
		FROM boc_projects WHERE status = 'active'
	`).Scan(&totalBudget, &totalSpent)
	if err != nil {
		totalBudget, totalSpent = 0, 0
	}

	var totalHours float64
	err = h.DB.QueryRow(`
		SELECT COALESCE(SUM(hours), 0)
		FROM boc_project_times pt
		JOIN boc_projects p ON pt.project_id = p.id
		WHERE p.status = 'active'
	`).Scan(&totalHours)
	if err != nil {
		totalHours = 0
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"total_budget": totalBudget,
		"total_spent":  totalSpent,
		"remaining":    totalBudget - totalSpent,
		"utilization":  map[string]interface{}{
			"percentage": map[bool]float64{true: (totalSpent / totalBudget) * 100, false: 0}[totalBudget > 0],
		},
		"total_hours": totalHours,
	})
}