package handlers

import (
	"database/sql"
	"fmt"
	"net/http"
	"time"

	"go-crm/internal/templates"

	"github.com/go-chi/chi/v5"
	"golang.org/x/crypto/bcrypt"
)

// package-level globals kept for existing tests; App methods use a.DB directly.
var DB *sql.DB

func (a *App) SignupPage(w http.ResponseWriter, r *http.Request) {
	content := fmt.Sprintf(`
<div class="min-h-[60vh] flex items-center justify-center">
    <div class="w-full max-w-sm">
        <div class="text-center mb-8">
            <div class="inline-flex items-center justify-center w-12 h-12 rounded-xl bg-amber-400/10 border border-amber-400/20 mb-4">
                <svg class="w-6 h-6 text-amber-400" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 10V3L4 14h7v7l9-11h-7z"/></svg>
            </div>
            <h1 class="text-2xl font-bold text-zinc-100 tracking-tight">go-crm</h1>
            <p class="text-sm text-zinc-500 mt-1">Create your account</p>
        </div>
        <div class="card-industrial p-6">
            <form method="POST" action="/auth/signup" class="space-y-4">
                <div>
                    <label class="block text-[10px] font-mono uppercase tracking-wider text-zinc-500 mb-1.5">Email</label>
                    <input type="email" name="email" required class="input-industrial" placeholder="you@company.com">
                </div>
                <div>
                    <label class="block text-[10px] font-mono uppercase tracking-wider text-zinc-500 mb-1.5">Name</label>
                    <input type="text" name="name" required class="input-industrial" placeholder="Your name">
                </div>
                <div>
                    <label class="block text-[10px] font-mono uppercase tracking-wider text-zinc-500 mb-1.5">Password</label>
                    <input type="password" name="password" required class="input-industrial" placeholder="Min 8 characters">
                </div>
                <button type="submit" class="btn-primary w-full justify-center mt-2">Create Account</button>
            </form>
        </div>
        <p class="text-center text-xs text-zinc-500 mt-6">Already have an account? <a href="/auth/login" class="text-amber-400 hover:text-amber-300 transition-colors">Sign in</a></p>
    </div>
</div>`)
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	templates.WriteHTMLPage(w, "Sign Up", "", content)
}

func (a *App) Signup(w http.ResponseWriter, r *http.Request) {
	r.ParseForm()
	email := r.FormValue("email")
	name := r.FormValue("name")
	password := r.FormValue("password")

	if email == "" || name == "" || password == "" {
		http.Error(w, "All fields required", http.StatusBadRequest)
		return
	}

	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		http.Error(w, "Failed to hash password", http.StatusInternalServerError)
		return
	}

	tx, err := a.DB.Begin()
	if err != nil {
		http.Error(w, "Failed to start transaction", http.StatusInternalServerError)
		return
	}
	defer tx.Rollback()

	_, err = tx.Exec(
		"INSERT INTO accounts (email, name, password, created_at) VALUES (?, ?, ?, ?)",
		email, name, string(hashedPassword), time.Now().Unix(),
	)
	if err != nil {
		http.Error(w, "Email already exists", http.StatusBadRequest)
		return
	}

	var accountID int64
	if err = tx.QueryRow("SELECT account_id FROM accounts WHERE email = ?", email).Scan(&accountID); err != nil {
		http.Error(w, "Failed to create account", http.StatusInternalServerError)
		return
	}

	if _, err = tx.Exec(
		"INSERT INTO clients (account_id, name, created_at) VALUES (?, ?, ?)",
		accountID, name, time.Now().Unix(),
	); err != nil {
		http.Error(w, "Failed to create client", http.StatusInternalServerError)
		return
	}

	sessionID := generateSessionID()
	expires := time.Now().Add(24 * time.Hour).Unix()
	if _, err = tx.Exec(
		"INSERT INTO sessions (session_id, account_id, expires) VALUES (?, ?, ?)",
		sessionID, accountID, expires,
	); err != nil {
		http.Error(w, "Failed to create session", http.StatusInternalServerError)
		return
	}

	if err = tx.Commit(); err != nil {
		http.Error(w, "Failed to commit signup", http.StatusInternalServerError)
		return
	}

	http.SetCookie(w, &http.Cookie{Name: "session", Value: sessionID, Path: "/"})
	http.Redirect(w, r, "/", http.StatusFound)
}

func (a *App) LoginPage(w http.ResponseWriter, r *http.Request) {
	content := fmt.Sprintf(`
<div class="min-h-[60vh] flex items-center justify-center">
    <div class="w-full max-w-sm">
        <div class="text-center mb-8">
            <div class="inline-flex items-center justify-center w-12 h-12 rounded-xl bg-amber-400/10 border border-amber-400/20 mb-4">
                <svg class="w-6 h-6 text-amber-400" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 10V3L4 14h7v7l9-11h-7z"/></svg>
            </div>
            <h1 class="text-2xl font-bold text-zinc-100 tracking-tight">go-crm</h1>
            <p class="text-sm text-zinc-500 mt-1">Sign in to your workspace</p>
        </div>
        <div class="card-industrial p-6">
            <form method="POST" action="/auth/login" class="space-y-4">
                <div>
                    <label class="block text-[10px] font-mono uppercase tracking-wider text-zinc-500 mb-1.5">Email</label>
                    <input type="email" name="email" required class="input-industrial" placeholder="you@company.com">
                </div>
                <div>
                    <label class="block text-[10px] font-mono uppercase tracking-wider text-zinc-500 mb-1.5">Password</label>
                    <input type="password" name="password" required class="input-industrial" placeholder="Enter your password">
                </div>
                <button type="submit" class="btn-primary w-full justify-center mt-2">Sign In</button>
            </form>
        </div>
        <p class="text-center text-xs text-zinc-500 mt-6">Don't have an account? <a href="/auth/signup" class="text-amber-400 hover:text-amber-300 transition-colors">Create one</a></p>
    </div>
</div>`)
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	templates.WriteHTMLPage(w, "Sign In", "", content)
}

func (a *App) Login(w http.ResponseWriter, r *http.Request) {
	r.ParseForm()
	email := r.FormValue("email")
	password := r.FormValue("password")

	var accountID int64
	var hashedPassword string
	err := a.DB.QueryRow("SELECT account_id, password FROM accounts WHERE email = ?", email).Scan(&accountID, &hashedPassword)
	if err != nil {
		http.Error(w, "Invalid credentials", http.StatusUnauthorized)
		return
	}

	if err := bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(password)); err != nil {
		http.Error(w, "Invalid credentials", http.StatusUnauthorized)
		return
	}

	sessionID := generateSessionID()
	expires := time.Now().Add(24 * time.Hour).Unix()

	_, err = a.DB.Exec("INSERT INTO sessions (session_id, account_id, expires) VALUES (?, ?, ?)", sessionID, accountID, expires)
	if err != nil {
		http.Error(w, "Failed to create session", http.StatusInternalServerError)
		return
	}

	http.SetCookie(w, &http.Cookie{Name: "session", Value: sessionID, Path: "/"})
	http.Redirect(w, r, "/", http.StatusFound)
}

func (a *App) Logout(w http.ResponseWriter, r *http.Request) {
	cookie, err := r.Cookie("session")
	if err == nil {
		a.DB.Exec("DELETE FROM sessions WHERE session_id = ?", cookie.Value)
	}
	http.SetCookie(w, &http.Cookie{Name: "session", Value: "", Path: "/", MaxAge: -1})
	http.Redirect(w, r, "/auth/login", http.StatusFound)
}

func (a *App) AccountPage(w http.ResponseWriter, r *http.Request) {
	accountID, ok := a.requireAuth(w, r)
	if !ok {
		return
	}

	var name, email string
	err := a.DB.QueryRow("SELECT name, email FROM accounts WHERE account_id = ?", accountID).Scan(&name, &email)
	if err != nil {
		http.Error(w, "Account not found", http.StatusNotFound)
		return
	}

	content := fmt.Sprintf(`
%s
<div class="max-w-lg animate-slide-up">
    <div class="card-industrial p-6">
        <form method="POST" action="/auth/account" class="space-y-4">
            <div>
                <label class="block text-[10px] font-mono uppercase tracking-wider text-zinc-500 mb-1.5">Name</label>
                <input type="text" name="name" value="%s" class="input-industrial">
            </div>
            <div>
                <label class="block text-[10px] font-mono uppercase tracking-wider text-zinc-500 mb-1.5">Email</label>
                <input type="email" value="%s" disabled class="input-industrial opacity-50 cursor-not-allowed">
            </div>
            <div>
                <label class="block text-[10px] font-mono uppercase tracking-wider text-zinc-500 mb-1.5">New Password</label>
                <input type="password" name="password" class="input-industrial" placeholder="Leave blank to keep current">
            </div>
            <div class="pt-2">
                <button type="submit" class="btn-primary">Update Account</button>
            </div>
        </form>
    </div>
</div>`, templates.PageHeader("Account Settings", "Manage your profile and security"), htmlEscape(name), htmlEscape(email))

	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	templates.WriteHTMLPage(w, "Account", "", content)
}

func (a *App) UpdateAccount(w http.ResponseWriter, r *http.Request) {
	accountID, ok := a.requireAuth(w, r)
	if !ok {
		return
	}

	r.ParseForm()
	name := r.FormValue("name")
	password := r.FormValue("password")

	if name != "" {
		a.DB.Exec("UPDATE accounts SET name = ? WHERE account_id = ?", name, accountID)
	}

	if password != "" {
		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
		if err == nil {
			a.DB.Exec("UPDATE accounts SET password = ? WHERE account_id = ?", string(hashedPassword), accountID)
		}
	}

	http.Redirect(w, r, "/auth/account", http.StatusFound)
}

// --- session helpers on App --------------------------------------------------

func (a *App) getSession(r *http.Request) (int64, error) {
	cookie, err := r.Cookie("session")
	if err != nil {
		return 0, err
	}
	var accountID int64
	err = a.DB.QueryRow(
		"SELECT account_id FROM sessions WHERE session_id = ? AND expires > ?",
		cookie.Value, time.Now().Unix(),
	).Scan(&accountID)
	return accountID, err
}

func (a *App) GetAccountID(r *http.Request) (int64, error) {
	return a.getSession(r)
}

func (a *App) requireAuth(w http.ResponseWriter, r *http.Request) (int64, bool) {
	accountID, err := a.getSession(r)
	if err != nil {
		if isAPIRequest(r) {
			w.Header().Set("Content-Type", "application/json; charset=utf-8")
			w.Write([]byte(`{"error":"unauthorized"}`))
		} else {
			http.Redirect(w, r, "/auth/login", http.StatusFound)
		}
		return 0, false
	}
	return accountID, true
}

func (a *App) clientIDForAccount(accountID int64) int64 {
	var clientID int64
	a.DB.QueryRow("SELECT client_id FROM clients WHERE account_id = ? LIMIT 1", accountID).Scan(&clientID)
	return clientID
}

// --- package-level shims kept for existing tests that set the global DB ------

func GetAccountID(r *http.Request) (int64, error) {
	return getSession(r)
}

func getSession(r *http.Request) (int64, error) {
	cookie, err := r.Cookie("session")
	if err != nil {
		return 0, err
	}
	var accountID int64
	err = DB.QueryRow(
		"SELECT account_id FROM sessions WHERE session_id = ? AND expires > ?",
		cookie.Value, time.Now().Unix(),
	).Scan(&accountID)
	return accountID, err
}

func requireAuth(w http.ResponseWriter, r *http.Request) (int64, bool) {
	accountID, err := getSession(r)
	if err != nil {
		if isAPIRequest(r) {
			w.Header().Set("Content-Type", "application/json; charset=utf-8")
			w.Write([]byte(`{"error":"unauthorized"}`))
		} else {
			http.Redirect(w, r, "/auth/login", http.StatusFound)
		}
		return 0, false
	}
	return accountID, true
}

func clientIDForAccount(accountID int64) int64 {
	var clientID int64
	DB.QueryRow("SELECT client_id FROM clients WHERE account_id = ? LIMIT 1", accountID).Scan(&clientID)
	return clientID
}

func isAPIRequest(r *http.Request) bool {
	accept := r.Header.Get("Accept")
	return accept == "application/json" || r.URL.Path == "/leads/qr"
}

func SetupAuthHandlers(db *sql.DB) {
	DB = db
	chi.RegisterMethod("GET")
}

// --- session ID generation ---------------------------------------------------

func generateSessionID() string {
	return time.Now().Format("20060102150405") + "-" + randomString(32)
}

func randomString(n int) string {
	const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	b := make([]byte, n)
	for i := range b {
		b[i] = letters[time.Now().UnixNano()%int64(len(letters))]
	}
	return string(b)
}

// SignupPage, Signup, LoginPage, Login, Logout, AccountPage, UpdateAccount
// are also kept as package-level functions for backward compat with test
// setups that call handlers.Signup directly. They delegate to the globals.

func SignupPage(w http.ResponseWriter, r *http.Request) {
	a := &App{DB: DB, WAConnector: WAConnector}
	a.SignupPage(w, r)
}

func Signup(w http.ResponseWriter, r *http.Request) {
	a := &App{DB: DB, WAConnector: WAConnector}
	a.Signup(w, r)
}

func LoginPage(w http.ResponseWriter, r *http.Request) {
	a := &App{DB: DB, WAConnector: WAConnector}
	a.LoginPage(w, r)
}

func Login(w http.ResponseWriter, r *http.Request) {
	a := &App{DB: DB, WAConnector: WAConnector}
	a.Login(w, r)
}

func Logout(w http.ResponseWriter, r *http.Request) {
	a := &App{DB: DB, WAConnector: WAConnector}
	a.Logout(w, r)
}

func AccountPage(w http.ResponseWriter, r *http.Request) {
	a := &App{DB: DB, WAConnector: WAConnector}
	a.AccountPage(w, r)
}

func UpdateAccount(w http.ResponseWriter, r *http.Request) {
	a := &App{DB: DB, WAConnector: WAConnector}
	a.UpdateAccount(w, r)
}