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

package provider

import (
	"context"
	"errors"
	"fmt"

	"terraform-provider-virtfusion/internal/client"

	"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/booldefault"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema/boolplanmodifier"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema/int64planmodifier"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema/listplanmodifier"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema/stringplanmodifier"
	"github.com/hashicorp/terraform-plugin-framework/types"
)

// Ensure provider-defined types fully satisfy framework interfaces.
var (
	_ resource.Resource              = &ServerBuildResource{}
	_ resource.ResourceWithConfigure = &ServerBuildResource{}
)

// NewServerBuildResource creates a new server build resource.
func NewServerBuildResource() resource.Resource {
	return &ServerBuildResource{}
}

// ServerBuildResource defines the resource implementation.
type ServerBuildResource struct {
	client *client.Client
}

// ServerBuildResourceModel describes the resource data model.
type ServerBuildResourceModel struct {
	ID       types.String `tfsdk:"id"`
	ServerID types.Int64  `tfsdk:"server_id"`
	Name     types.String `tfsdk:"name"`
	Hostname types.String `tfsdk:"hostname"`
	OSID     types.Int64  `tfsdk:"osid"`
	VNC      types.Bool   `tfsdk:"vnc"`
	Ipv6     types.Bool   `tfsdk:"ipv6"`
	SSHKeys  types.List   `tfsdk:"ssh_keys"`
	Email    types.Bool   `tfsdk:"email"`
}

func (r *ServerBuildResource) Metadata(_ context.Context, req resource.MetadataRequest, resp *resource.MetadataResponse) {
	resp.TypeName = req.ProviderTypeName + "_server_build"
}

func (r *ServerBuildResource) Schema(_ context.Context, _ resource.SchemaRequest, resp *resource.SchemaResponse) {
	resp.Schema = schema.Schema{
		MarkdownDescription: "Builds a VirtFusion server with an operating system. This is a one-time operation — once a server is built, it stays built.",
		Attributes: map[string]schema.Attribute{
			"id": schema.StringAttribute{
				MarkdownDescription: "The identifier of the server build (same as server_id).",
				Computed:            true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.UseStateForUnknown(),
				},
			},
			"server_id": schema.Int64Attribute{
				MarkdownDescription: "The ID of the server to build.",
				Required:            true,
				PlanModifiers: []planmodifier.Int64{
					int64planmodifier.RequiresReplace(),
				},
			},
			"name": schema.StringAttribute{
				MarkdownDescription: "The name for the server build.",
				Required:            true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.RequiresReplace(),
				},
			},
			"osid": schema.Int64Attribute{
				MarkdownDescription: "The operating system ID to install.",
				Required:            true,
				PlanModifiers: []planmodifier.Int64{
					int64planmodifier.RequiresReplace(),
				},
			},
			"hostname": schema.StringAttribute{
				MarkdownDescription: "The hostname for the server.",
				Optional:            true,
				PlanModifiers: []planmodifier.String{
					stringplanmodifier.RequiresReplace(),
				},
			},
			"vnc": schema.BoolAttribute{
				MarkdownDescription: "Whether to enable VNC access.",
				Optional:            true,
				Computed:            true,
				Default:             booldefault.StaticBool(false),
				PlanModifiers: []planmodifier.Bool{
					boolplanmodifier.RequiresReplace(),
				},
			},
			"ipv6": schema.BoolAttribute{
				MarkdownDescription: "Whether to enable IPv6.",
				Optional:            true,
				Computed:            true,
				Default:             booldefault.StaticBool(false),
				PlanModifiers: []planmodifier.Bool{
					boolplanmodifier.RequiresReplace(),
				},
			},
			"ssh_keys": schema.ListAttribute{
				MarkdownDescription: "List of SSH key IDs to add to the server.",
				Optional:            true,
				ElementType:         types.Int64Type,
				PlanModifiers: []planmodifier.List{
					listplanmodifier.RequiresReplace(),
				},
			},
			"email": schema.BoolAttribute{
				MarkdownDescription: "Whether to send a notification email after build.",
				Optional:            true,
				Computed:            true,
				Default:             booldefault.StaticBool(false),
				PlanModifiers: []planmodifier.Bool{
					boolplanmodifier.RequiresReplace(),
				},
			},
		},
	}
}

func (r *ServerBuildResource) Configure(_ context.Context, req resource.ConfigureRequest, resp *resource.ConfigureResponse) {
	if req.ProviderData == nil {
		return
	}

	c, ok := req.ProviderData.(*client.Client)
	if !ok {
		resp.Diagnostics.AddError(
			"Unexpected Resource Configure Type",
			fmt.Sprintf("Expected *client.Client, got: %T. Please report this issue to the provider developers.", req.ProviderData),
		)
		return
	}

	r.client = c
}

func (r *ServerBuildResource) Create(ctx context.Context, req resource.CreateRequest, resp *resource.CreateResponse) {
	var data ServerBuildResourceModel
	resp.Diagnostics.Append(req.Plan.Get(ctx, &data)...)
	if resp.Diagnostics.HasError() {
		return
	}

	// Build the API request body.
	buildReq := client.ServerBuildRequest{
		Name:              data.Name.ValueString(),
		OperatingSystemID: data.OSID.ValueInt64(),
		VNC:               data.VNC.ValueBool(),
		Ipv6:              data.Ipv6.ValueBool(),
		Email:             data.Email.ValueBool(),
	}

	if !data.Hostname.IsNull() && !data.Hostname.IsUnknown() {
		buildReq.Hostname = data.Hostname.ValueString()
	}

	// Convert ssh_keys from types.List to []int64.
	if !data.SSHKeys.IsNull() && !data.SSHKeys.IsUnknown() {
		var sshKeys []int64
		resp.Diagnostics.Append(data.SSHKeys.ElementsAs(ctx, &sshKeys, false)...)
		if resp.Diagnostics.HasError() {
			return
		}
		buildReq.SSHKeys = sshKeys
	}

	apiPath := fmt.Sprintf("/servers/%d/build", data.ServerID.ValueInt64())
	_, err := r.client.Post(ctx, apiPath, buildReq)
	if err != nil {
		resp.Diagnostics.AddError(
			"Error Building Server",
			fmt.Sprintf("Could not build server %d: %s", data.ServerID.ValueInt64(), err),
		)
		return
	}

	// Set the ID to the server_id.
	data.ID = types.StringValue(fmt.Sprintf("%d", data.ServerID.ValueInt64()))

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

func (r *ServerBuildResource) Read(ctx context.Context, req resource.ReadRequest, resp *resource.ReadResponse) {
	var data ServerBuildResourceModel
	resp.Diagnostics.Append(req.State.Get(ctx, &data)...)
	if resp.Diagnostics.HasError() {
		return
	}

	// Verify the server still exists.
	apiPath := fmt.Sprintf("/servers/%d", data.ServerID.ValueInt64())
	_, err := r.client.Get(ctx, apiPath)
	if err != nil {
		var apiErr *client.APIError
		if errors.As(err, &apiErr) && apiErr.IsNotFound() {
			// Server no longer exists, remove from state.
			resp.State.RemoveResource(ctx)
			return
		}

		resp.Diagnostics.AddError(
			"Error Reading Server",
			fmt.Sprintf("Could not read server %d: %s", data.ServerID.ValueInt64(), err),
		)
		return
	}

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

func (r *ServerBuildResource) Update(ctx context.Context, req resource.UpdateRequest, resp *resource.UpdateResponse) {
	var data ServerBuildResourceModel
	resp.Diagnostics.Append(req.Plan.Get(ctx, &data)...)
	if resp.Diagnostics.HasError() {
		return
	}

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

func (r *ServerBuildResource) Delete(_ context.Context, _ resource.DeleteRequest, _ *resource.DeleteResponse) {
	// No-op: building a server is not reversible. Removing from state only.
}

// ValidateConfig validates the resource configuration.
func (r *ServerBuildResource) ValidateConfig(ctx context.Context, req resource.ValidateConfigRequest, resp *resource.ValidateConfigResponse) {
	var data ServerBuildResourceModel
	resp.Diagnostics.Append(req.Config.Get(ctx, &data)...)
	if resp.Diagnostics.HasError() {
		return
	}

	// Validate server_id is positive.
	if !data.ServerID.IsNull() && !data.ServerID.IsUnknown() && data.ServerID.ValueInt64() <= 0 {
		resp.Diagnostics.AddAttributeError(
			path.Root("server_id"),
			"Invalid Server ID",
			"server_id must be a positive integer.",
		)
	}

	// Validate osid is positive.
	if !data.OSID.IsNull() && !data.OSID.IsUnknown() && data.OSID.ValueInt64() <= 0 {
		resp.Diagnostics.AddAttributeError(
			path.Root("osid"),
			"Invalid OS ID",
			"osid must be a positive integer.",
		)
	}
}