package networkarearoute

import (
	"context"
	"fmt"
	"net/http"
	"strings"

	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/utils"

	iaasUtils "github.com/stackitcloud/terraform-provider-stackit/stackit/internal/services/iaas/utils"

	"github.com/hashicorp/terraform-plugin-framework/path"
	"github.com/hashicorp/terraform-plugin-framework/resource"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema/stringplanmodifier"
	"github.com/hashicorp/terraform-plugin-framework/schema/validator"
	"github.com/hashicorp/terraform-plugin-framework/types"
	"github.com/hashicorp/terraform-plugin-log/tflog"
	"github.com/stackitcloud/stackit-sdk-go/core/oapierror"
	"github.com/stackitcloud/stackit-sdk-go/services/iaas"
	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/conversion"
	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/core"
	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/validate"
)

// Ensure the implementation satisfies the expected interfaces.
var (
	_ resource.Resource                = &networkAreaRouteResource{}
	_ resource.ResourceWithConfigure   = &networkAreaRouteResource{}
	_ resource.ResourceWithImportState = &networkAreaRouteResource{}
)

type Model struct {
	Id                 types.String `tfsdk:"id"` // needed by TF
	OrganizationId     types.String `tfsdk:"organization_id"`
	NetworkAreaId      types.String `tfsdk:"network_area_id"`
	NetworkAreaRouteId types.String `tfsdk:"network_area_route_id"`
	NextHop            types.String `tfsdk:"next_hop"`
	Prefix             types.String `tfsdk:"prefix"`
	Labels             types.Map    `tfsdk:"labels"`
}

// NewNetworkAreaRouteResource is a helper function to simplify the provider implementation.
func NewNetworkAreaRouteResource() resource.Resource {
	return &networkAreaRouteResource{}
}

// networkResource is the resource implementation.
type networkAreaRouteResource struct {
	client *iaas.APIClient
}

// Metadata returns the resource type name.
func (r *networkAreaRouteResource) Metadata(_ context.Context, req resource.MetadataRequest, resp *resource.MetadataResponse) {
	resp.TypeName = req.ProviderTypeName + "_network_area_route"
}

// Configure adds the provider configured client to the resource.
func (r *networkAreaRouteResource) Configure(ctx context.Context, req resource.ConfigureRequest, resp *resource.ConfigureResponse) {
	providerData, ok := conversion.ParseProviderData(ctx, req.ProviderData, &resp.Diagnostics)
	if !ok {
		return
	}

	apiClient := iaasUtils.ConfigureClient(ctx, &providerData, &resp.Diagnostics)
	if resp.Diagnostics.HasError() {
		return
	}
	r.client = apiClient
	tflog.Info(ctx, "IaaS client configured")
}

// Schema defines the schema for the resource.
func (r *networkAreaRouteResource) Schema(_ context.Context, _ resource.SchemaRequest, resp *resource.SchemaResponse) {
	description := "Network area route resource schema. Must have a `region` specified in the provider configuration."
	resp.Schema = schema.Schema{
		Description:         description,
		MarkdownDescription: description,
		Attributes: map[string]schema.Attribute{
			"id": schema.StringAttribute{
				Description: "Terraform's internal resource ID. It is structured as \"`organization_id`,`network_area_id`,`network_area_route_id`\".",
				Computed:    true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.UseStateForUnknown(),
				},
			},
			"organization_id": schema.StringAttribute{
				Description: "STACKIT organization ID to which the network area is associated.",
				Required:    true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.RequiresReplace(),
				},
				Validators: []validator.String{
					validate.UUID(),
					validate.NoSeparator(),
				},
			},
			"network_area_id": schema.StringAttribute{
				Description: "The network area ID to which the network area route is associated.",
				Required:    true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.UseStateForUnknown(),
					stringplanmodifier.RequiresReplace(),
				},
				Validators: []validator.String{
					validate.UUID(),
					validate.NoSeparator(),
				},
			},
			"network_area_route_id": schema.StringAttribute{
				Description: "The network area route ID.",
				Computed:    true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.UseStateForUnknown(),
					stringplanmodifier.RequiresReplace(),
				},
				Validators: []validator.String{
					validate.UUID(),
					validate.NoSeparator(),
				},
			},
			"next_hop": schema.StringAttribute{
				Description: "The IP address of the routing system, that will route the prefix configured. Should be a valid IPv4 address.",
				Required:    true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.RequiresReplace(),
				},
				Validators: []validator.String{
					validate.IP(false),
				},
			},
			"prefix": schema.StringAttribute{
				Description: "The network, that is reachable though the Next Hop. Should use CIDR notation.",
				Required:    true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.RequiresReplace(),
				},
				Validators: []validator.String{
					validate.CIDR(),
				},
			},
			"labels": schema.MapAttribute{
				Description: "Labels are key-value string pairs which can be attached to a resource container",
				ElementType: types.StringType,
				Optional:    true,
			},
		},
	}
}

// Create creates the resource and sets the initial Terraform state.
func (r *networkAreaRouteResource) Create(ctx context.Context, req resource.CreateRequest, resp *resource.CreateResponse) { // nolint:gocritic // function signature required by Terraform
	// Retrieve values from plan
	var model Model
	diags := req.Plan.Get(ctx, &model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}

	ctx = core.InitProviderContext(ctx)

	organizationId := model.OrganizationId.ValueString()
	ctx = tflog.SetField(ctx, "organization_id", organizationId)
	networkAreaId := model.NetworkAreaId.ValueString()
	ctx = tflog.SetField(ctx, "network_area_id", networkAreaId)

	// Generate API request body from model
	payload, err := toCreatePayload(ctx, &model)
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error creating network area route", fmt.Sprintf("Creating API payload: %v", err))
		return
	}

	// Create new network area route
	routes, err := r.client.CreateNetworkAreaRoute(ctx, organizationId, networkAreaId).CreateNetworkAreaRoutePayload(*payload).Execute()
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error creating network area route", fmt.Sprintf("Calling API: %v", err))
		return
	}

	ctx = core.LogResponse(ctx)

	if routes.Items == nil || len(*routes.Items) == 0 {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error creating network area route.", "Empty response from API")
		return
	}

	if len(*routes.Items) != 1 {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error creating network area route.", "New static route not found or more than 1 route found in API response.")
		return
	}

	// Gets the route ID from the first element, routes.Items[0]
	routeItems := *routes.Items
	route := routeItems[0]
	routeId := *route.RouteId

	ctx = tflog.SetField(ctx, "network_area_route_id", routeId)

	// Map response body to schema
	err = mapFields(ctx, &route, &model)
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error creating network area route.", fmt.Sprintf("Processing API payload: %v", err))
		return
	}
	// Set state to fully populated data
	diags = resp.State.Set(ctx, model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}
	tflog.Info(ctx, "Network area route created")
}

// Read refreshes the Terraform state with the latest data.
func (r *networkAreaRouteResource) Read(ctx context.Context, req resource.ReadRequest, resp *resource.ReadResponse) { // nolint:gocritic // function signature required by Terraform
	var model Model
	diags := req.State.Get(ctx, &model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}
	organizationId := model.OrganizationId.ValueString()
	networkAreaId := model.NetworkAreaId.ValueString()
	networkAreaRouteId := model.NetworkAreaRouteId.ValueString()

	ctx = core.InitProviderContext(ctx)

	ctx = tflog.SetField(ctx, "organization_id", organizationId)
	ctx = tflog.SetField(ctx, "network_area_id", networkAreaId)
	ctx = tflog.SetField(ctx, "network_area_route_id", networkAreaRouteId)

	networkAreaRouteResp, err := r.client.GetNetworkAreaRoute(ctx, organizationId, networkAreaId, networkAreaRouteId).Execute()
	if err != nil {
		oapiErr, ok := err.(*oapierror.GenericOpenAPIError) //nolint:errorlint //complaining that error.As should be used to catch wrapped errors, but this error should not be wrapped
		if ok && oapiErr.StatusCode == http.StatusNotFound {
			resp.State.RemoveResource(ctx)
			return
		}
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error reading network area route.", fmt.Sprintf("Calling API: %v", err))
		return
	}

	ctx = core.LogResponse(ctx)

	// Map response body to schema
	err = mapFields(ctx, networkAreaRouteResp, &model)
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error reading network area route", fmt.Sprintf("Processing API payload: %v", err))
		return
	}
	// Set refreshed state
	diags = resp.State.Set(ctx, model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}
	tflog.Info(ctx, "Network area route read")
}

// Delete deletes the resource and removes the Terraform state on success.
func (r *networkAreaRouteResource) Delete(ctx context.Context, req resource.DeleteRequest, resp *resource.DeleteResponse) { // nolint:gocritic // function signature required by Terraform
	// Retrieve values from state
	var model Model
	diags := req.State.Get(ctx, &model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}

	organizationId := model.OrganizationId.ValueString()
	networkAreaId := model.NetworkAreaId.ValueString()
	networkAreaRouteId := model.NetworkAreaRouteId.ValueString()

	ctx = core.InitProviderContext(ctx)

	ctx = tflog.SetField(ctx, "organization_id", organizationId)
	ctx = tflog.SetField(ctx, "network_area_id", networkAreaId)
	ctx = tflog.SetField(ctx, "network_area_route_id", networkAreaRouteId)

	// Delete existing network
	err := r.client.DeleteNetworkAreaRoute(ctx, organizationId, networkAreaId, networkAreaRouteId).Execute()
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error deleting network area route", fmt.Sprintf("Calling API: %v", err))
		return
	}

	ctx = core.LogResponse(ctx)

	tflog.Info(ctx, "Network area route deleted")
}

// Update updates the resource and sets the updated Terraform state on success.
func (r *networkAreaRouteResource) Update(ctx context.Context, req resource.UpdateRequest, resp *resource.UpdateResponse) { // nolint:gocritic // function signature required by Terraform
	// Retrieve values from plan
	var model Model
	diags := req.Plan.Get(ctx, &model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}

	organizationId := model.OrganizationId.ValueString()
	networkAreaId := model.NetworkAreaId.ValueString()
	networkAreaRouteId := model.NetworkAreaRouteId.ValueString()

	ctx = core.InitProviderContext(ctx)

	ctx = tflog.SetField(ctx, "organization_id", organizationId)
	ctx = tflog.SetField(ctx, "network_area_id", networkAreaId)
	ctx = tflog.SetField(ctx, "network_area_route_id", networkAreaRouteId)

	// Retrieve values from state
	var stateModel Model
	diags = req.State.Get(ctx, &stateModel)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}

	// Generate API request body from model
	payload, err := toUpdatePayload(ctx, &model, stateModel.Labels)
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error updating network area route", fmt.Sprintf("Creating API payload: %v", err))
		return
	}
	// Update existing network area route
	networkAreaRouteResp, err := r.client.UpdateNetworkAreaRoute(ctx, organizationId, networkAreaId, networkAreaRouteId).UpdateNetworkAreaRoutePayload(*payload).Execute()
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error updating network area route", fmt.Sprintf("Calling API: %v", err))
		return
	}

	ctx = core.LogResponse(ctx)

	err = mapFields(ctx, networkAreaRouteResp, &model)
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error updating network area route", fmt.Sprintf("Processing API payload: %v", err))
		return
	}
	diags = resp.State.Set(ctx, model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}
	tflog.Info(ctx, "Network area route updated")
}

// ImportState imports a resource into the Terraform state on success.
// The expected format of the resource import identifier is: organization_id,network_aread_id,network_area_route_id
func (r *networkAreaRouteResource) ImportState(ctx context.Context, req resource.ImportStateRequest, resp *resource.ImportStateResponse) {
	idParts := strings.Split(req.ID, core.Separator)

	if len(idParts) != 3 || idParts[0] == "" || idParts[1] == "" || idParts[2] == "" {
		core.LogAndAddError(ctx, &resp.Diagnostics,
			"Error importing network area route",
			fmt.Sprintf("Expected import identifier with format: [organization_id],[network_area_id],[network_area_route_id]  Got: %q", req.ID),
		)
		return
	}

	organizationId := idParts[0]
	networkAreaId := idParts[1]
	networkAreaRouteId := idParts[2]
	ctx = tflog.SetField(ctx, "organization_id", organizationId)
	ctx = tflog.SetField(ctx, "network_area_id", networkAreaId)
	ctx = tflog.SetField(ctx, "network_area_route_id", networkAreaRouteId)

	resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("organization_id"), organizationId)...)
	resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("network_area_id"), networkAreaId)...)
	resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("network_area_route_id"), networkAreaRouteId)...)
	tflog.Info(ctx, "Network area route state imported")
}

func mapFields(ctx context.Context, networkAreaRoute *iaas.Route, model *Model) error {
	if networkAreaRoute == nil {
		return fmt.Errorf("response input is nil")
	}
	if model == nil {
		return fmt.Errorf("model input is nil")
	}

	var networkAreaRouteId string
	if model.NetworkAreaRouteId.ValueString() != "" {
		networkAreaRouteId = model.NetworkAreaRouteId.ValueString()
	} else if networkAreaRoute.RouteId != nil {
		networkAreaRouteId = *networkAreaRoute.RouteId
	} else {
		return fmt.Errorf("network area route id not present")
	}

	model.Id = utils.BuildInternalTerraformId(model.OrganizationId.ValueString(), model.NetworkAreaId.ValueString(), networkAreaRouteId)

	labels, err := iaasUtils.MapLabels(ctx, networkAreaRoute.Labels, model.Labels)
	if err != nil {
		return err
	}

	model.NetworkAreaRouteId = types.StringValue(networkAreaRouteId)
	model.NextHop = types.StringPointerValue(networkAreaRoute.Nexthop)
	model.Prefix = types.StringPointerValue(networkAreaRoute.Prefix)
	model.Labels = labels
	return nil
}

func toCreatePayload(ctx context.Context, model *Model) (*iaas.CreateNetworkAreaRoutePayload, error) {
	if model == nil {
		return nil, fmt.Errorf("nil model")
	}

	labels, err := conversion.ToStringInterfaceMap(ctx, model.Labels)
	if err != nil {
		return nil, fmt.Errorf("converting to Go map: %w", err)
	}

	return &iaas.CreateNetworkAreaRoutePayload{
		Ipv4: &[]iaas.Route{
			{
				Prefix:  conversion.StringValueToPointer(model.Prefix),
				Nexthop: conversion.StringValueToPointer(model.NextHop),
				Labels:  &labels,
			},
		},
	}, nil
}

func toUpdatePayload(ctx context.Context, model *Model, currentLabels types.Map) (*iaas.UpdateNetworkAreaRoutePayload, error) {
	if model == nil {
		return nil, fmt.Errorf("nil model")
	}

	labels, err := conversion.ToJSONMapPartialUpdatePayload(ctx, currentLabels, model.Labels)
	if err != nil {
		return nil, fmt.Errorf("converting to Go map: %w", err)
	}

	return &iaas.UpdateNetworkAreaRoutePayload{
		Labels: &labels,
	}, nil
}