package hcl2template

import (
	"fmt"
	"time"

	"github.com/hashicorp/hcl/v2"
	"github.com/hashicorp/hcl/v2/gohcl"
	"github.com/hashicorp/packer/packer"
)

// OnlyExcept is a struct that is meant to be embedded that contains the
// logic required for "only" and "except" meta-parameters.
type OnlyExcept struct {
	Only   []string `json:"only,omitempty"`
	Except []string `json:"except,omitempty"`
}

// Skip says whether or not to skip the build with the given name.
func (o *OnlyExcept) Skip(n string) bool {
	if len(o.Only) > 0 {
		for _, v := range o.Only {
			if v == n {
				return false
			}
		}

		return true
	}

	if len(o.Except) > 0 {
		for _, v := range o.Except {
			if v == n {
				return true
			}
		}

		return false
	}

	return false
}

// Validate validates that the OnlyExcept settings are correct for a thing.
func (o *OnlyExcept) Validate() hcl.Diagnostics {
	var diags hcl.Diagnostics

	if len(o.Only) > 0 && len(o.Except) > 0 {
		diags = diags.Append(&hcl.Diagnostic{
			Summary:  "only one of 'only' or 'except' may be specified",
			Severity: hcl.DiagError,
		})
	}

	return diags
}

// ProvisionerBlock references a detected but unparsed provisioner
type ProvisionerBlock struct {
	PType       string
	PName       string
	PauseBefore time.Duration
	MaxRetries  int
	Timeout     time.Duration
	OnlyExcept  OnlyExcept
	HCL2Ref
}

func (p *ProvisionerBlock) String() string {
	return fmt.Sprintf(buildProvisionerLabel+"-block %q %q", p.PType, p.PName)
}

func (p *Parser) decodeProvisioner(block *hcl.Block) (*ProvisionerBlock, hcl.Diagnostics) {
	var b struct {
		Name        string   `hcl:"name,optional"`
		PauseBefore string   `hcl:"pause_before,optional"`
		MaxRetries  int      `hcl:"max_retries,optional"`
		Timeout     string   `hcl:"timeout,optional"`
		Only        []string `hcl:"only,optional"`
		Except      []string `hcl:"except,optional"`
		Rest        hcl.Body `hcl:",remain"`
	}
	diags := gohcl.DecodeBody(block.Body, nil, &b)
	if diags.HasErrors() {
		return nil, diags
	}

	provisioner := &ProvisionerBlock{
		PType:      block.Labels[0],
		PName:      b.Name,
		MaxRetries: b.MaxRetries,
		OnlyExcept: OnlyExcept{Only: b.Only, Except: b.Except},
		HCL2Ref:    newHCL2Ref(block, b.Rest),
	}

	diags = diags.Extend(provisioner.OnlyExcept.Validate())
	if diags.HasErrors() {
		return nil, diags
	}

	if b.PauseBefore != "" {
		pauseBefore, err := time.ParseDuration(b.PauseBefore)
		if err != nil {
			return nil, append(diags, &hcl.Diagnostic{
				Summary: "Failed to parse pause_before duration",
				Detail:  err.Error(),
			})
		}
		provisioner.PauseBefore = pauseBefore
	}

	if b.Timeout != "" {
		timeout, err := time.ParseDuration(b.Timeout)
		if err != nil {
			return nil, append(diags, &hcl.Diagnostic{
				Summary: "Failed to parse timeout duration",
				Detail:  err.Error(),
			})
		}
		provisioner.Timeout = timeout
	}

	if !p.ProvisionersSchemas.Has(provisioner.PType) {
		diags = append(diags, &hcl.Diagnostic{
			Summary:  fmt.Sprintf("Unknown "+buildProvisionerLabel+" type %q", provisioner.PType),
			Subject:  block.LabelRanges[0].Ptr(),
			Detail:   fmt.Sprintf("known "+buildProvisionerLabel+"s: %v", p.ProvisionersSchemas.List()),
			Severity: hcl.DiagError,
		})
		return nil, diags
	}
	return provisioner, diags
}

func (cfg *PackerConfig) startProvisioner(source SourceBlock, pb *ProvisionerBlock, ectx *hcl.EvalContext, generatedVars map[string]interface{}) (packer.Provisioner, hcl.Diagnostics) {
	var diags hcl.Diagnostics

	provisioner, err := cfg.provisionersSchemas.Start(pb.PType)
	if err != nil {
		diags = append(diags, &hcl.Diagnostic{
			Summary: fmt.Sprintf("failed loading %s", pb.PType),
			Subject: pb.HCL2Ref.LabelsRanges[0].Ptr(),
			Detail:  err.Error(),
		})
		return nil, diags
	}
	p := &HCL2Provisioner{
		Provisioner:      provisioner,
		provisionerBlock: pb,
		evalContext:      ectx,
		builderVariables: source.builderVariables(),
	}
	err = p.HCL2Prepare(generatedVars)
	if err != nil {
		diags = append(diags, &hcl.Diagnostic{
			Severity: hcl.DiagError,
			Summary:  fmt.Sprintf("Failed preparing %s", pb),
			Detail:   err.Error(),
			Subject:  pb.HCL2Ref.DefRange.Ptr(),
		})
		return nil, diags
	}
	return p, diags
}