// 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 = &ServerDataSource{}
var _ datasource.DataSourceWithConfigure = &ServerDataSource{}

// NewServerDataSource returns a new data source for reading a single server.
func NewServerDataSource() datasource.DataSource {
	return &ServerDataSource{}
}

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

// ServerDataSourceModel describes the data source data model.
type ServerDataSourceModel struct {
	ID           types.Int64  `tfsdk:"id"`
	UUID         types.String `tfsdk:"uuid"`
	Name         types.String `tfsdk:"name"`
	Hostname     types.String `tfsdk:"hostname"`
	OwnerID      types.Int64  `tfsdk:"owner_id"`
	HypervisorID types.Int64  `tfsdk:"hypervisor_id"`
	Suspended    types.Bool   `tfsdk:"suspended"`
	CPUCores     types.Int64  `tfsdk:"cpu_cores"`
	Memory       types.Int64  `tfsdk:"memory"`
	Storage      types.Int64  `tfsdk:"storage"`
}

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

func (d *ServerDataSource) Schema(_ context.Context, _ datasource.SchemaRequest, resp *datasource.SchemaResponse) {
	resp.Schema = schema.Schema{
		MarkdownDescription: "Use this data source to read a single VirtFusion server by ID.",
		Attributes: map[string]schema.Attribute{
			"id": schema.Int64Attribute{
				MarkdownDescription: "The server ID.",
				Required:            true,
			},
			"uuid": schema.StringAttribute{
				MarkdownDescription: "The server UUID.",
				Computed:            true,
			},
			"name": schema.StringAttribute{
				MarkdownDescription: "The server display name.",
				Computed:            true,
			},
			"hostname": schema.StringAttribute{
				MarkdownDescription: "The server hostname.",
				Computed:            true,
			},
			"owner_id": schema.Int64Attribute{
				MarkdownDescription: "The owner (user) ID who owns the server.",
				Computed:            true,
			},
			"hypervisor_id": schema.Int64Attribute{
				MarkdownDescription: "The hypervisor ID where the server is hosted.",
				Computed:            true,
			},
			"suspended": schema.BoolAttribute{
				MarkdownDescription: "Whether the server is suspended.",
				Computed:            true,
			},
			"cpu_cores": schema.Int64Attribute{
				MarkdownDescription: "The number of CPU cores.",
				Computed:            true,
			},
			"memory": schema.Int64Attribute{
				MarkdownDescription: "The memory size in MB.",
				Computed:            true,
			},
			"storage": schema.Int64Attribute{
				MarkdownDescription: "The storage size in GB.",
				Computed:            true,
			},
		},
	}
}

func (d *ServerDataSource) 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. Please report this issue to the provider developers.", req.ProviderData),
		)
		return
	}

	d.client = c
}

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

	result, err := d.client.Get(ctx, fmt.Sprintf("/servers/%d", data.ID.ValueInt64()))
	if err != nil {
		resp.Diagnostics.AddError("Error Reading Server", err.Error())
		return
	}

	var serverResp client.ServerResponse
	if err := json.Unmarshal(result, &serverResp); err != nil {
		resp.Diagnostics.AddError("Error Parsing Server Response", err.Error())
		return
	}

	s := serverResp.Data
	data.ID = types.Int64Value(s.ID)
	data.UUID = types.StringValue(s.UUID)
	data.Name = types.StringValue(s.Name)
	data.Hostname = types.StringValue(s.Hostname)
	data.OwnerID = types.Int64Value(s.OwnerID)
	data.HypervisorID = types.Int64Value(s.HypervisorID)
	data.Suspended = types.BoolValue(s.Suspended)

	// Extract nested resource values from the detailed server response.
	var cpuCores, memory, storage int64
	if s.CPU != nil {
		cpuCores = s.CPU.Cores
	}
	if s.Settings != nil && s.Settings.Resources != nil {
		memory = s.Settings.Resources.Memory
		storage = s.Settings.Resources.Storage
	}
	data.CPUCores = types.Int64Value(cpuCores)
	data.Memory = types.Int64Value(memory)
	data.Storage = types.Int64Value(storage)

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