// Copyright (c) EZSCALE.
// SPDX-License-Identifier: MPL-2.0

package provider

import (
	"context"
	"encoding/json"
	"fmt"

	"terraform-provider-virtfusion/internal/client"

	"github.com/hashicorp/terraform-plugin-framework/datasource"
	"github.com/hashicorp/terraform-plugin-framework/datasource/schema"
	"github.com/hashicorp/terraform-plugin-framework/types"
)

var (
	_ datasource.DataSource              = &HypervisorGroupResourcesDataSource{}
	_ datasource.DataSourceWithConfigure = &HypervisorGroupResourcesDataSource{}
)

// NewHypervisorGroupResourcesDataSource returns a new hypervisor group resources data source.
func NewHypervisorGroupResourcesDataSource() datasource.DataSource {
	return &HypervisorGroupResourcesDataSource{}
}

// HypervisorGroupResourcesDataSource defines the data source implementation.
type HypervisorGroupResourcesDataSource struct {
	client *client.Client
}

// HypervisorGroupResourcesDataSourceModel describes the data source data model.
type HypervisorGroupResourcesDataSourceModel struct {
	ID       types.Int64 `tfsdk:"id"`
	Results  types.Int64 `tfsdk:"results"`
	CPUCores types.Int64 `tfsdk:"cpu_cores"`
	Memory   types.Int64 `tfsdk:"memory"`
	Storage  types.Int64 `tfsdk:"storage"`
}

func (d *HypervisorGroupResourcesDataSource) Metadata(_ context.Context, req datasource.MetadataRequest, resp *datasource.MetadataResponse) {
	resp.TypeName = req.ProviderTypeName + "_hypervisor_group_resources"
}

func (d *HypervisorGroupResourcesDataSource) Schema(_ context.Context, _ datasource.SchemaRequest, resp *datasource.SchemaResponse) {
	resp.Schema = schema.Schema{
		MarkdownDescription: "Fetches resource information for a VirtFusion hypervisor group.",
		Attributes: map[string]schema.Attribute{
			"id": schema.Int64Attribute{
				MarkdownDescription: "The hypervisor group ID.",
				Required:            true,
			},
			"results": resultsSchemaAttribute(),
			"cpu_cores": schema.Int64Attribute{
				MarkdownDescription: "The number of CPU cores available in the group.",
				Computed:            true,
			},
			"memory": schema.Int64Attribute{
				MarkdownDescription: "The amount of memory available in the group.",
				Computed:            true,
			},
			"storage": schema.Int64Attribute{
				MarkdownDescription: "The amount of storage available in the group.",
				Computed:            true,
			},
		},
	}
}

func (d *HypervisorGroupResourcesDataSource) Configure(_ context.Context, req datasource.ConfigureRequest, resp *datasource.ConfigureResponse) {
	if req.ProviderData == nil {
		return
	}

	c, ok := req.ProviderData.(*client.Client)
	if !ok {
		resp.Diagnostics.AddError(
			"Unexpected Data Source Configure Type",
			fmt.Sprintf("Expected *client.Client, got: %T.", req.ProviderData),
		)
		return
	}

	d.client = c
}

func (d *HypervisorGroupResourcesDataSource) Read(ctx context.Context, req datasource.ReadRequest, resp *datasource.ReadResponse) {
	var data HypervisorGroupResourcesDataSourceModel
	resp.Diagnostics.Append(req.Config.Get(ctx, &data)...)
	if resp.Diagnostics.HasError() {
		return
	}

	rawResp, err := d.client.GetAllPages(ctx, fmt.Sprintf("/compute/hypervisors/groups/%d/resources?%s", data.ID.ValueInt64(), resultsQueryParam(data.Results)))
	if err != nil {
		resp.Diagnostics.AddError("Error Reading Hypervisor Group Resources", err.Error())
		return
	}

	var resourcesResp client.HypervisorGroupResourcesResponse
	if err := json.Unmarshal(rawResp, &resourcesResp); err != nil {
		resp.Diagnostics.AddError("Error Parsing Hypervisor Group Resources Response", err.Error())
		return
	}

	// Aggregate resource totals across all hypervisors in the group.
	var totalCPU, totalMemory, totalStorage int64
	for _, entry := range resourcesResp.Data {
		totalCPU += entry.Resources.CPUCores.Max
		totalMemory += entry.Resources.Memory.Max
		totalStorage += entry.Resources.LocalStorage.Max
	}
	data.CPUCores = types.Int64Value(totalCPU)
	data.Memory = types.Int64Value(totalMemory)
	data.Storage = types.Int64Value(totalStorage)

	resp.Diagnostics.Append(resp.State.Set(ctx, &data)...)
}