package postgresflexalpha

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

	"github.com/hashicorp/terraform-plugin-framework/datasource"
	"github.com/hashicorp/terraform-plugin-framework/datasource/schema"
	"github.com/hashicorp/terraform-plugin-framework/diag"
	"github.com/hashicorp/terraform-plugin-framework/types"
	"github.com/hashicorp/terraform-plugin-log/tflog"
	"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"
	postgresflexalpha2 "tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/stackit/internal/services/postgresflexalpha/database/datasources_gen"
	postgresflexUtils "tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/stackit/internal/services/postgresflexalpha/utils"
	"tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/stackit/internal/utils"

	"tf-provider.git.onstackit.cloud/stackit-dev-tools/terraform-provider-stackitprivatepreview/pkg_gen/postgresflexalpha"
)

// Ensure the implementation satisfies the expected interfaces.
var (
	_ datasource.DataSource = &databaseDataSource{}
)

// NewDatabaseDataSource is a helper function to simplify the provider implementation.
func NewDatabaseDataSource() datasource.DataSource {
	return &databaseDataSource{}
}

// dataSourceModel maps the data source schema data.
type dataSourceModel struct {
	postgresflexalpha2.DatabaseModel
	TerraformID types.String `tfsdk:"id"`
}

// databaseDataSource is the data source implementation.
type databaseDataSource struct {
	client       *postgresflexalpha.APIClient
	providerData core.ProviderData
}

// Metadata returns the data source type name.
func (r *databaseDataSource) Metadata(
	_ context.Context,
	req datasource.MetadataRequest,
	resp *datasource.MetadataResponse,
) {
	resp.TypeName = req.ProviderTypeName + "_postgresflexalpha_database"
}

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

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

// Schema defines the schema for the data source.
func (r *databaseDataSource) Schema(ctx context.Context, _ datasource.SchemaRequest, resp *datasource.SchemaResponse) {

	s := postgresflexalpha2.DatabaseDataSourceSchema(ctx)
	s.Attributes["id"] = schema.StringAttribute{
		Description: "Terraform's internal resource ID. It is structured as \\\"`project_id`,`region`,`instance_id`," +
			"`database_id`\\\".\",",
		Computed: true,
	}

	resp.Schema = s
}

// Read fetches the data for the data source.
func (r *databaseDataSource) Read(
	ctx context.Context,
	req datasource.ReadRequest,
	resp *datasource.ReadResponse,
) { // nolint:gocritic // function signature required by Terraform
	var model dataSourceModel
	diags := req.Config.Get(ctx, &model)
	resp.Diagnostics.Append(diags...)
	if resp.Diagnostics.HasError() {
		return
	}

	ctx = core.InitProviderContext(ctx)

	projectId := model.ProjectId.ValueString()
	instanceId := model.InstanceId.ValueString()
	region := r.providerData.GetRegionWithOverride(model.Region)
	ctx = tflog.SetField(ctx, "project_id", projectId)
	ctx = tflog.SetField(ctx, "instance_id", instanceId)
	ctx = tflog.SetField(ctx, "region", region)

	databaseResp, err := r.getDatabaseByNameOrID(ctx, &model, projectId, region, instanceId, &resp.Diagnostics)
	if resp.Diagnostics.HasError() {
		return
	}
	if err != nil {
		handleReadError(ctx, &resp.Diagnostics, err, projectId, instanceId)
		resp.State.RemoveResource(ctx)
		return
	}

	ctx = core.LogResponse(ctx)

	// Map response body to schema and populate Computed attribute values
	err = mapFields(databaseResp, &model, region)
	if err != nil {
		core.LogAndAddError(
			ctx,
			&resp.Diagnostics,
			"Error reading database",
			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, "Postgres Flex database read")
}

// getDatabaseByNameOrID retrieves a single database by ensuring either a unique ID or name is provided.
func (r *databaseDataSource) getDatabaseByNameOrID(
	ctx context.Context,
	model *dataSourceModel,
	projectId, region, instanceId string,
	diags *diag.Diagnostics,
) (*postgresflexalpha.ListDatabase, error) {
	isIdSet := !model.DatabaseId.IsNull() && !model.DatabaseId.IsUnknown()
	isNameSet := !model.Name.IsNull() && !model.Name.IsUnknown()

	if (isIdSet && isNameSet) || (!isIdSet && !isNameSet) {
		diags.AddError(
			"Invalid configuration",
			"Exactly one of 'id' or 'name' must be specified.",
		)
		return nil, nil
	}

	if isIdSet {
		databaseId := model.DatabaseId.ValueInt64()
		ctx = tflog.SetField(ctx, "database_id", databaseId)
		return getDatabaseById(ctx, r.client, projectId, region, instanceId, databaseId)
	}

	databaseName := model.Name.ValueString()
	ctx = tflog.SetField(ctx, "name", databaseName)
	return getDatabaseByName(ctx, r.client, projectId, region, instanceId, databaseName)
}

// handleReadError centralizes API error handling for the Read operation.
func handleReadError(ctx context.Context, diags *diag.Diagnostics, err error, projectId, instanceId string) {
	utils.LogError(
		ctx,
		diags,
		err,
		"Reading database",
		fmt.Sprintf(
			"Could not retrieve database for instance %q in project %q.",
			instanceId,
			projectId,
		),
		map[int]string{
			http.StatusBadRequest: fmt.Sprintf(
				"Invalid request parameters for project %q and instance %q.",
				projectId,
				instanceId,
			),
			http.StatusNotFound: fmt.Sprintf(
				"Database, instance %q, or project %q not found.",
				instanceId,
				projectId,
			),
			http.StatusForbidden: fmt.Sprintf("Forbidden access to project %q.", projectId),
		},
	)
}