package sqlserverflexalpha

import (
	"context"
	_ "embed"
	"errors"
	"fmt"
	"net/http"
	"strconv"
	"strings"

	"github.com/hashicorp/terraform-plugin-framework/path"
	"github.com/hashicorp/terraform-plugin-framework/resource"
	"github.com/hashicorp/terraform-plugin-framework/resource/identityschema"
	"github.com/hashicorp/terraform-plugin-framework/types"
	"github.com/hashicorp/terraform-plugin-log/tflog"
	"github.com/stackitcloud/stackit-sdk-go/core/config"
	"github.com/stackitcloud/stackit-sdk-go/core/oapierror"

	"tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/pkg_gen/sqlserverflexalpha"
	"tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/stackit/internal/conversion"

	"tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/stackit/internal/core"
	"tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/stackit/internal/utils"

	sqlserverflexalphaGen "tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/stackit/internal/services/sqlserverflexalpha/database/resources_gen"
)

var (
	_ resource.Resource                = &databaseResource{}
	_ resource.ResourceWithConfigure   = &databaseResource{}
	_ resource.ResourceWithImportState = &databaseResource{}
	_ resource.ResourceWithModifyPlan  = &databaseResource{}
	_ resource.ResourceWithIdentity    = &databaseResource{}

	// Define errors
	errDatabaseNotFound = errors.New("database not found")

	// Error message constants
	extractErrorSummary = "extracting failed"
	extractErrorMessage = "Extracting identity data: %v"
)

func NewDatabaseResource() resource.Resource {
	return &databaseResource{}
}

// resourceModel describes the resource data model.
type resourceModel = sqlserverflexalphaGen.DatabaseModel

// DatabaseResourceIdentityModel describes the resource's identity attributes.
type DatabaseResourceIdentityModel struct {
	ProjectID    types.String `tfsdk:"project_id"`
	Region       types.String `tfsdk:"region"`
	InstanceID   types.String `tfsdk:"instance_id"`
	DatabaseName types.String `tfsdk:"database_name"`
}

type databaseResource struct {
	client       *sqlserverflexalpha.APIClient
	providerData core.ProviderData
}

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

//go:embed planModifiers.yaml
var modifiersFileByte []byte

func (r *databaseResource) Schema(ctx context.Context, _ resource.SchemaRequest, resp *resource.SchemaResponse) {
	s := sqlserverflexalphaGen.DatabaseResourceSchema(ctx)

	fields, err := utils.ReadModifiersConfig(modifiersFileByte)
	if err != nil {
		resp.Diagnostics.AddError("error during read modifiers config file", err.Error())
		return
	}

	err = utils.AddPlanModifiersToResourceSchema(fields, &s)
	if err != nil {
		resp.Diagnostics.AddError("error adding plan modifiers", err.Error())
		return
	}
	resp.Schema = s
}

func (r *databaseResource) IdentitySchema(
	_ context.Context,
	_ resource.IdentitySchemaRequest,
	resp *resource.IdentitySchemaResponse,
) {
	resp.IdentitySchema = identityschema.Schema{
		Attributes: map[string]identityschema.Attribute{
			"project_id": identityschema.StringAttribute{
				RequiredForImport: true, // must be set during import by the practitioner
			},
			"region": identityschema.StringAttribute{
				RequiredForImport: true, // can be defaulted by the provider configuration
			},
			"instance_id": identityschema.StringAttribute{
				RequiredForImport: true, // can be defaulted by the provider configuration
			},
			"database_name": identityschema.StringAttribute{
				RequiredForImport: true, // can be defaulted by the provider configuration
			},
		},
	}
}

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

	apiClientConfigOptions := []config.ConfigurationOption{
		config.WithCustomAuth(r.providerData.RoundTripper),
		utils.UserAgentConfigOption(r.providerData.Version),
	}
	if r.providerData.PostgresFlexCustomEndpoint != "" {
		apiClientConfigOptions = append(
			apiClientConfigOptions,
			config.WithEndpoint(r.providerData.PostgresFlexCustomEndpoint),
		)
	} else {
		apiClientConfigOptions = append(apiClientConfigOptions, config.WithRegion(r.providerData.GetRegion()))
	}
	apiClient, err := sqlserverflexalpha.NewAPIClient(apiClientConfigOptions...)
	if err != nil {
		resp.Diagnostics.AddError(
			"Error configuring API client",
			fmt.Sprintf(
				"Configuring client: %v. This is an error related to the provider configuration, not to the resource configuration",
				err,
			),
		)
		return
	}
	r.client = apiClient
	tflog.Info(ctx, "sqlserverflexalpha.Database client configured")
}

func (r *databaseResource) Create(ctx context.Context, req resource.CreateRequest, resp *resource.CreateResponse) {
	var model resourceModel

	diags := req.Plan.Get(ctx, &model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}

	ctx = core.InitProviderContext(ctx)

	projectId := model.ProjectId.ValueString()
	region := model.Region.ValueString()
	instanceId := model.InstanceId.ValueString()

	ctx = tflog.SetField(ctx, "project_id", projectId)
	ctx = tflog.SetField(ctx, "instance_id", instanceId)
	ctx = tflog.SetField(ctx, "region", region)

	// Generate API request body from model
	payload, err := toCreatePayload(&model)
	if err != nil {
		core.LogAndAddError(
			ctx,
			&resp.Diagnostics,
			"Error creating database",
			fmt.Sprintf("Creating API payload: %v", err),
		)
		return
	}
	// Create new database
	databaseResp, err := r.client.CreateDatabaseRequest(
		ctx,
		projectId,
		region,
		instanceId,
	).CreateDatabaseRequestPayload(*payload).Execute()
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error creating database", fmt.Sprintf("Calling API: %v", err))
		return
	}

	ctx = core.LogResponse(ctx)

	if databaseResp == nil || databaseResp.Id == nil {
		core.LogAndAddError(
			ctx,
			&resp.Diagnostics,
			"Error creating database",
			"API didn't return database Id. A database might have been created",
		)
		return
	}

	databaseId := *databaseResp.Id
	databaseName := model.DatabaseName.String()

	ctx = tflog.SetField(ctx, "database_id", databaseId)
	ctx = tflog.SetField(ctx, "database_name", databaseName)

	ctx = core.LogResponse(ctx)

	// Set data returned by API in identity
	identity := DatabaseResourceIdentityModel{
		ProjectID:    types.StringValue(projectId),
		Region:       types.StringValue(region),
		InstanceID:   types.StringValue(instanceId),
		DatabaseName: types.StringValue(databaseName),
	}
	resp.Diagnostics.Append(resp.Identity.Set(ctx, identity)...)
	if resp.Diagnostics.HasError() {
		return
	}

	database, err := r.client.GetDatabaseRequest(ctx, projectId, region, instanceId, databaseName).Execute()
	if err != nil {
		core.LogAndAddError(
			ctx,
			&resp.Diagnostics,
			"Error creating database",
			fmt.Sprintf("Getting database details after creation: %v", err),
		)
		return
	}

	// Map response body to schema
	err = mapResourceFields(database, &model, region)
	if err != nil {
		core.LogAndAddError(
			ctx,
			&resp.Diagnostics,
			"Error creating database",
			fmt.Sprintf("Processing API payload: %v", err),
		)
		return
	}

	// Set state to fully populated data
	resp.Diagnostics.Append(resp.State.Set(ctx, model)...)
	if resp.Diagnostics.HasError() {
		return
	}

	tflog.Info(ctx, "sqlserverflexalpha.Database created")
}

func (r *databaseResource) Read(ctx context.Context, req resource.ReadRequest, resp *resource.ReadResponse) {
	var model resourceModel
	diags := req.State.Get(ctx, &model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}

	// Read identity data
	var identityData DatabaseResourceIdentityModel
	resp.Diagnostics.Append(req.Identity.Get(ctx, &identityData)...)
	if resp.Diagnostics.HasError() {
		return
	}

	ctx = core.InitProviderContext(ctx)

	projectId, region, instanceId, databaseName, errExt := r.extractIdentityData(model, identityData)
	if errExt != nil {
		core.LogAndAddError(
			ctx,
			&resp.Diagnostics,
			extractErrorSummary,
			fmt.Sprintf(extractErrorMessage, errExt),
		)
	}

	ctx = tflog.SetField(ctx, "project_id", projectId)
	ctx = tflog.SetField(ctx, "instance_id", instanceId)
	ctx = tflog.SetField(ctx, "region", region)
	ctx = tflog.SetField(ctx, "database_name", databaseName)

	databaseResp, err := r.client.GetDatabaseRequest(ctx, projectId, region, instanceId, databaseName).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) || errors.Is(err, errDatabaseNotFound) {
			resp.State.RemoveResource(ctx)
			return
		}
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error reading database", fmt.Sprintf("Calling API: %v", err))
		return
	}

	ctx = core.LogResponse(ctx)

	// Map response body to schema
	err = mapResourceFields(databaseResp, &model, region)
	if err != nil {
		core.LogAndAddError(
			ctx,
			&resp.Diagnostics,
			"Error reading database",
			fmt.Sprintf("Processing API payload: %v", err),
		)
		return
	}

	// Set data returned by API in identity
	identity := DatabaseResourceIdentityModel{
		ProjectID:    types.StringValue(projectId),
		Region:       types.StringValue(region),
		InstanceID:   types.StringValue(instanceId),
		DatabaseName: types.StringValue(databaseName),
	}
	resp.Diagnostics.Append(resp.Identity.Set(ctx, identity)...)
	if resp.Diagnostics.HasError() {
		return
	}

	// Set refreshed state
	resp.Diagnostics.Append(resp.State.Set(ctx, &model)...)
	if resp.Diagnostics.HasError() {
		return
	}

	tflog.Info(ctx, "sqlserverflexalpha.Database read")
}

func (r *databaseResource) Update(ctx context.Context, _ resource.UpdateRequest, resp *resource.UpdateResponse) {
	// TODO: Check update api endpoint - not available at the moment, so return an error for now
	core.LogAndAddError(ctx, &resp.Diagnostics, "Error updating database", "Database can't be updated")
}

func (r *databaseResource) Delete(ctx context.Context, req resource.DeleteRequest, resp *resource.DeleteResponse) {
	// nolint:gocritic // function signature required by Terraform
	var model resourceModel
	diags := req.State.Get(ctx, &model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}

	// Read identity data
	var identityData DatabaseResourceIdentityModel
	resp.Diagnostics.Append(req.Identity.Get(ctx, &identityData)...)
	if resp.Diagnostics.HasError() {
		return
	}

	ctx = core.InitProviderContext(ctx)

	projectId, region, instanceId, databaseName, errExt := r.extractIdentityData(model, identityData)
	if errExt != nil {
		core.LogAndAddError(
			ctx,
			&resp.Diagnostics,
			extractErrorSummary,
			fmt.Sprintf(extractErrorMessage, errExt),
		)
	}

	ctx = tflog.SetField(ctx, "project_id", projectId)
	ctx = tflog.SetField(ctx, "instance_id", instanceId)
	ctx = tflog.SetField(ctx, "region", region)
	ctx = tflog.SetField(ctx, "database_name", databaseName)

	// Delete existing record set
	err := r.client.DeleteDatabaseRequestExecute(ctx, projectId, region, instanceId, databaseName)
	if err != nil {
		core.LogAndAddError(ctx, &resp.Diagnostics, "Error deleting database", fmt.Sprintf("Calling API: %v", err))
	}

	ctx = core.LogResponse(ctx)
	resp.State.RemoveResource(ctx)

	tflog.Info(ctx, "sqlserverflexalpha.Database deleted")
}

// ModifyPlan implements resource.ResourceWithModifyPlan.
// Use the modifier to set the effective region in the current plan.
func (r *databaseResource) ModifyPlan(
	ctx context.Context,
	req resource.ModifyPlanRequest,
	resp *resource.ModifyPlanResponse,
) { // nolint:gocritic // function signature required by Terraform
	var configModel resourceModel
	// skip initial empty configuration to avoid follow-up errors
	if req.Config.Raw.IsNull() {
		return
	}
	resp.Diagnostics.Append(req.Config.Get(ctx, &configModel)...)
	if resp.Diagnostics.HasError() {
		return
	}

	var planModel resourceModel
	resp.Diagnostics.Append(req.Plan.Get(ctx, &planModel)...)
	if resp.Diagnostics.HasError() {
		return
	}

	utils.AdaptRegion(ctx, configModel.Region, &planModel.Region, r.providerData.GetRegion(), resp)
	if resp.Diagnostics.HasError() {
		return
	}

	resp.Diagnostics.Append(resp.Plan.Set(ctx, planModel)...)
	if resp.Diagnostics.HasError() {
		return
	}
}

// ImportState imports a resource into the Terraform state on success.
// The expected import identifier format is: [project_id],[region],[instance_id],[database_id]
func (r *databaseResource) ImportState(
	ctx context.Context,
	req resource.ImportStateRequest,
	resp *resource.ImportStateResponse,
) {

	ctx = core.InitProviderContext(ctx)

	if req.ID != "" {

		idParts := strings.Split(req.ID, core.Separator)

		if len(idParts) != 4 || idParts[0] == "" || idParts[1] == "" || idParts[2] == "" || idParts[3] == "" {
			core.LogAndAddError(
				ctx, &resp.Diagnostics,
				"Error importing database",
				fmt.Sprintf(
					"Expected import identifier with format [project_id],[region],[instance_id],[database_name], got %q",
					req.ID,
				),
			)
			return
		}

		databaseId, err := strconv.ParseInt(idParts[3], 10, 64)
		if err != nil {
			core.LogAndAddError(
				ctx,
				&resp.Diagnostics,
				"Error importing database",
				fmt.Sprintf("Invalid database_id format: %q. It must be a valid integer.", idParts[3]),
			)
			return
		}

		resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("project_id"), idParts[0])...)
		resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("region"), idParts[1])...)
		resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("instance_id"), idParts[2])...)
		resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("database_name"), databaseId)...)

		core.LogAndAddWarning(
			ctx,
			&resp.Diagnostics,
			"Sqlserverflexalpha database imported with empty password",
			"The database password is not imported as it is only available upon creation of a new database. The password field will be empty.",
		)
		tflog.Info(ctx, "Sqlserverflexalpha database state imported")
	}

	// If no ID is provided, attempt to read identity attributes from the import configuration
	var identityData DatabaseResourceIdentityModel
	resp.Diagnostics.Append(req.Identity.Get(ctx, &identityData)...)
	if resp.Diagnostics.HasError() {
		return
	}

	projectId := identityData.ProjectID.ValueString()
	region := identityData.Region.ValueString()
	instanceId := identityData.InstanceID.ValueString()
	databaseName := identityData.DatabaseName.ValueString()

	resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("project_id"), projectId)...)
	resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("region"), region)...)
	resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("instance_id"), instanceId)...)
	resp.Diagnostics.Append(resp.State.SetAttribute(ctx, path.Root("database_name"), databaseName)...)

	tflog.Info(ctx, "Sqlserverflexalpha database state imported")
}

// extractIdentityData extracts essential identifiers from the resource model, falling back to the identity model.
func (r *databaseResource) extractIdentityData(
	model resourceModel,
	identity DatabaseResourceIdentityModel,
) (projectId, region, instanceId, databaseName string, err error) {
	if !model.Name.IsNull() && !model.Name.IsUnknown() {
		databaseName = model.Name.ValueString()
	} else {
		if identity.DatabaseName.IsNull() || identity.DatabaseName.IsUnknown() {
			return "", "", "", "", fmt.Errorf("database_name not found in config")
		}
		databaseName = identity.DatabaseName.ValueString()
	}

	if !model.ProjectId.IsNull() && !model.ProjectId.IsUnknown() {
		projectId = model.ProjectId.ValueString()
	} else {
		if identity.ProjectID.IsNull() || identity.ProjectID.IsUnknown() {
			return "", "", "", "", fmt.Errorf("project_id not found in config")
		}
		projectId = identity.ProjectID.ValueString()
	}

	if !model.Region.IsNull() && !model.Region.IsUnknown() {
		region = r.providerData.GetRegionWithOverride(model.Region)
	} else {
		if identity.Region.IsNull() || identity.Region.IsUnknown() {
			return "", "", "", "", fmt.Errorf("region not found in config")
		}
		region = r.providerData.GetRegionWithOverride(identity.Region)
	}

	if !model.InstanceId.IsNull() && !model.InstanceId.IsUnknown() {
		instanceId = model.InstanceId.ValueString()
	} else {
		if identity.InstanceID.IsNull() || identity.InstanceID.IsUnknown() {
			return "", "", "", "", fmt.Errorf("instance_id not found in config")
		}
		instanceId = identity.InstanceID.ValueString()
	}
	return projectId, region, instanceId, databaseName, nil
}