package v1

import (
	"net/http"

	"github.com/gin-gonic/gin"

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	"github.com/gochat/gochat/internal/service"
	"github.com/gochat/gochat/pkg/pagination"
	"github.com/gochat/gochat/pkg/response"
)

// PlatformAccountHandler handles Platform API account endpoints (AccessToken auth).
// Reference: Chatwoot Platform::Api::V1::AccountsController — AccessToken authenticated
//
// Uses Permissible system: PlatformApp must have permissible access to operate
// on specific accounts. Create/index auto-permissible.
type PlatformAccountHandler struct {
	accountRepo     *repository.AccountRepo
	permissibleRepo *repository.PermissibleRepo
	accountSvc      *service.AccountService
}

// NewPlatformAccountHandler creates a new PlatformAccount handler.
func NewPlatformAccountHandler(
	accountRepo *repository.AccountRepo,
	permissibleRepo *repository.PermissibleRepo,
	accountSvc *service.AccountService,
) *PlatformAccountHandler {
	return &PlatformAccountHandler{
		accountRepo:     accountRepo,
		permissibleRepo: permissibleRepo,
		accountSvc:      accountSvc,
	}
}

// List returns all accounts the PlatformApp has permissible access to.
// GET /platform/api/v1/accounts
// Reference: Chatwoot Platform::Api::V1::AccountsController#index
func (h *PlatformAccountHandler) List(c *gin.Context) {
	platformAppID := getPlatformAppID(c)
	page := pagination.Parse(c)

	permissibles, err := h.permissibleRepo.FindByPlatformAppID(c.Request.Context(), platformAppID)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusInternalServerError, response.ErrInternal, err.Error())
		return
	}

	var accounts []model.Account
	var total int64
	for _, perm := range permissibles {
		if perm.PermissibleType == model.PermissibleTypeAccount {
			acct, err := h.accountRepo.FindByID(c.Request.Context(), perm.PermissibleID)
			if err != nil {
				continue
			}
			accounts = append(accounts, *acct)
		}
	}
	total = int64(len(accounts))

	start := page.Offset
	if start > len(accounts) {
		start = len(accounts)
	}
	end := start + page.PerPage
	if end > len(accounts) {
		end = len(accounts)
	}

	response.OKWithMeta(c, accounts[start:end], page.Page, page.PerPage, total)
}

// Show retrieves an account by ID.
// GET /platform/api/v1/accounts/:id
// Reference: Chatwoot Platform::Api::V1::AccountsController#show
// Requires: Permissible verification
func (h *PlatformAccountHandler) Show(c *gin.Context) {
	accountID, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account ID")
		return
	}

	platformAppID := getPlatformAppID(c)

	// Verify Permissible access
	perm, err := h.permissibleRepo.FindByPlatformAppAndResource(c.Request.Context(), platformAppID, model.PermissibleTypeAccount, accountID)
	if err != nil || perm == nil {
		response.AbortWithStatusError(c, http.StatusForbidden, response.ErrForbidden, "non permissible resource")
		return
	}

	acct, err := h.accountRepo.FindByID(c.Request.Context(), accountID)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusNotFound, response.ErrNotFound, "account not found")
		return
	}

	response.OK(c, acct)
}

// Create creates a new account and auto-creates Permissible record.
// POST /platform/api/v1/accounts
// Reference: Chatwoot Platform::Api::V1::AccountsController#create
// Auto-permissible: PlatformApp automatically gets access to the created account.
func (h *PlatformAccountHandler) Create(c *gin.Context) {
	platformAppID := getPlatformAppID(c)

	var req struct {
		Name     string `json:"name" binding:"required"`
		Domain   string `json:"domain,omitempty"`
		Locale   string `json:"locale,omitempty"`
		Timezone string `json:"timezone,omitempty"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, err.Error())
		return
	}

	acct := &model.Account{
		Name:     req.Name,
		Domain:   req.Domain,
		Locale:   defaultStr(req.Locale, "en"),
		Timezone: defaultStr(req.Timezone, "UTC"),
		Active:   true,
		Status:   "active",
	}

	if err := h.accountRepo.Create(c.Request.Context(), acct); err != nil {
		response.AbortWithStatusError(c, http.StatusInternalServerError, response.ErrInternal, err.Error())
		return
	}

	// Auto-create Permissible
	perm := &model.Permissible{
		PlatformAppID:   platformAppID,
		PermissibleType: model.PermissibleTypeAccount,
		PermissibleID:   acct.ID,
	}
	if err := h.permissibleRepo.Create(c.Request.Context(), perm); err != nil {
		// Non-critical — log but don't block account creation
	}

	response.Created(c, acct)
}

// Update updates an account.
// PATCH /platform/api/v1/accounts/:id
// Reference: Chatwoot Platform::Api::V1::AccountsController#update
// Requires: Permissible verification
func (h *PlatformAccountHandler) Update(c *gin.Context) {
	accountID, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account ID")
		return
	}

	platformAppID := getPlatformAppID(c)

	// Verify Permissible access
	perm, err := h.permissibleRepo.FindByPlatformAppAndResource(c.Request.Context(), platformAppID, model.PermissibleTypeAccount, accountID)
	if err != nil || perm == nil {
		response.AbortWithStatusError(c, http.StatusForbidden, response.ErrForbidden, "non permissible resource")
		return
	}

	acct, err := h.accountRepo.FindByID(c.Request.Context(), accountID)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusNotFound, response.ErrNotFound, "account not found")
		return
	}

	var req struct {
		Name     string `json:"name,omitempty"`
		Domain   string `json:"domain,omitempty"`
		Locale   string `json:"locale,omitempty"`
		Timezone string `json:"timezone,omitempty"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, err.Error())
		return
	}

	if req.Name != "" {
		acct.Name = req.Name
	}
	if req.Domain != "" {
		acct.Domain = req.Domain
	}
	if req.Locale != "" {
		acct.Locale = req.Locale
	}
	if req.Timezone != "" {
		acct.Timezone = req.Timezone
	}

	if err := h.accountRepo.Update(c.Request.Context(), acct); err != nil {
		response.AbortWithStatusError(c, http.StatusInternalServerError, response.ErrInternal, err.Error())
		return
	}

	response.OK(c, acct)
}

// Destroy deletes an account.
// DELETE /platform/api/v1/accounts/:id
// Reference: Chatwoot Platform::Api::V1::AccountsController#destroy
// Requires: Permissible verification
func (h *PlatformAccountHandler) Destroy(c *gin.Context) {
	accountID, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account ID")
		return
	}

	platformAppID := getPlatformAppID(c)

	// Verify Permissible access
	perm, err := h.permissibleRepo.FindByPlatformAppAndResource(c.Request.Context(), platformAppID, model.PermissibleTypeAccount, accountID)
	if err != nil || perm == nil {
		response.AbortWithStatusError(c, http.StatusForbidden, response.ErrForbidden, "non permissible resource")
		return
	}

	if err := h.accountRepo.Delete(c.Request.Context(), accountID); err != nil {
		response.AbortWithStatusError(c, http.StatusInternalServerError, response.ErrInternal, err.Error())
		return
	}

	response.NoContent(c)
}

// --- Helper ---

func defaultStr(val, fallback string) string {
	if val == "" {
		return fallback
	}
	return val
}